remove obsolete comment

.cargo/config.toml

@@ -1,10 +1,3 @@
 [alias]
 dev = "run --package ruff_dev --bin ruff_dev"
 benchmark = "bench -p ruff_benchmark --bench linter --bench formatter --"
-
-# statically link the C runtime so the executable does not depend on
-# that shared/dynamic library.
-#
-# See: https://github.com/astral-sh/ruff/issues/11503
-[target.'cfg(all(target_env="msvc", target_os = "windows"))']
-rustflags = ["-C", "target-feature=+crt-static"]

.devcontainer/devcontainer.json

@@ -20,7 +20,7 @@
 			"extensions": [
 				"ms-python.python",
 				"rust-lang.rust-analyzer",
-				"fill-labs.dependi",
+				"serayuzgur.crates",
 				"tamasfe.even-better-toml",
 				"Swellaby.vscode-rust-test-adapter",
 				"charliermarsh.ruff"

.editorconfig

@@ -17,7 +17,4 @@ indent_size = 4
 trim_trailing_whitespace = false
 
 [*.md]
-max_line_length = 100
-
-[*.toml]
-indent_size = 4
+max_line_length = 100

.gitattributes

@@ -8,10 +8,6 @@ crates/ruff_linter/resources/test/fixtures/pycodestyle/W391_3.py text eol=crlf
 crates/ruff_python_formatter/resources/test/fixtures/ruff/docstring_code_examples_crlf.py text eol=crlf
 crates/ruff_python_formatter/tests/snapshots/format@docstring_code_examples_crlf.py.snap text eol=crlf
 
-crates/ruff_python_parser/resources/invalid/re_lexing/line_continuation_windows_eol.py text eol=crlf
-crates/ruff_python_parser/resources/invalid/re_lex_logical_token_windows_eol.py text eol=crlf
-crates/ruff_python_parser/resources/invalid/re_lex_logical_token_mac_eol.py text eol=cr
-
 crates/ruff_python_parser/resources/inline linguist-generated=true
 
 ruff.schema.json linguist-generated=true text=auto eol=lf

.github/CODEOWNERS

@@ -15,7 +15,3 @@
 
 # Script for fuzzing the parser
 /scripts/fuzz-parser/ @AlexWaygood
-
-# red-knot
-/crates/red_knot* @carljm @MichaReiser @AlexWaygood @sharkdp
-/crates/ruff_db/ @carljm @MichaReiser @AlexWaygood @sharkdp

.github/renovate.json5

@@ -8,32 +8,15 @@
   semanticCommits: "disabled",
   separateMajorMinor: false,
   prHourlyLimit: 10,
-  enabledManagers: ["github-actions", "pre-commit", "cargo", "pep621", "pip_requirements", "npm"],
+  enabledManagers: ["github-actions", "pre-commit", "cargo", "pep621", "npm"],
   cargo: {
     // See https://docs.renovatebot.com/configuration-options/#rangestrategy
     rangeStrategy: "update-lockfile",
   },
   pep621: {
-    // The default for this package manager is to only search for `pyproject.toml` files
-    // found at the repository root: https://docs.renovatebot.com/modules/manager/pep621/#file-matching
     fileMatch: ["^(python|scripts)/.*pyproject\\.toml$"],
   },
-  pip_requirements: {
-    // The default for this package manager is to run on all requirements.txt files:
-    // https://docs.renovatebot.com/modules/manager/pip_requirements/#file-matching
-    // `fileMatch` doesn't work for excluding files; to exclude `requirements.txt` files
-    // outside the `doc/` directory, we instead have to use `ignorePaths`. Unlike `fileMatch`,
-    // which takes a regex string, `ignorePaths` takes a glob string, so we have to use
-    // a "negative glob pattern".
-    // See:
-    // - https://docs.renovatebot.com/modules/manager/#ignoring-files-that-match-the-default-filematch
-    // - https://docs.renovatebot.com/configuration-options/#ignorepaths
-    // - https://docs.renovatebot.com/string-pattern-matching/#negative-matching
-    ignorePaths: ["!docs/requirements*.txt"]
-  },
   npm: {
-    // The default for this package manager is to only search for `package.json` files
-    // found at the repository root: https://docs.renovatebot.com/modules/manager/npm/#file-matching
     fileMatch: ["^playground/.*package\\.json$"],
   },
   "pre-commit": {
@@ -44,35 +27,9 @@
       // Group upload/download artifact updates, the versions are dependent
       groupName: "Artifact GitHub Actions dependencies",
       matchManagers: ["github-actions"],
-      matchDatasources: ["gitea-tags", "github-tags"],
       matchPackagePatterns: ["actions/.*-artifact"],
       description: "Weekly update of artifact-related GitHub Actions dependencies",
     },
-    {
-      // This package rule disables updates for GitHub runners:
-      // we'd only pin them to a specific version
-      // if there was a deliberate reason to do so
-      groupName: "GitHub runners",
-      matchManagers: ["github-actions"],
-      matchDatasources: ["github-runners"],
-      description: "Disable PRs updating GitHub runners (e.g. 'runs-on: macos-14')",
-      enabled: false,
-    },
-    {
-      // Disable updates of `zip-rs`; intentionally pinned for now due to ownership change
-      // See: https://github.com/astral-sh/uv/issues/3642
-      matchPackagePatterns: ["zip"],
-      matchManagers: ["cargo"],
-      enabled: false,
-    },
-    {
-      // `mkdocs-material` requires a manual update to keep the version in sync
-      // with `mkdocs-material-insider`.
-      // See: https://squidfunk.github.io/mkdocs-material/insiders/upgrade/
-      matchManagers: ["pip_requirements"],
-      matchPackagePatterns: ["mkdocs-material"],
-      enabled: false,
-    },
     {
       groupName: "pre-commit dependencies",
       matchManagers: ["pre-commit"],

.github/workflows/build-docker.yml

@@ -1,290 +0,0 @@
-# Build and publish a Docker image.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a local
-# artifacts job within `cargo-dist`.
-#
-# TODO(charlie): Ideally, the publish step would happen as a publish job within `cargo-dist`, but
-# sharing the built image as an artifact between jobs is challenging.
-name: "[ruff] Build Docker image"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-  pull_request:
-    paths:
-      - .github/workflows/build-docker.yml
-
-env:
-  RUFF_BASE_IMG: ghcr.io/${{ github.repository_owner }}/ruff
-
-jobs:
-  docker-build:
-    name: Build Docker image (ghcr.io/astral-sh/ruff) for ${{ matrix.platform }}
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    strategy:
-      fail-fast: false
-      matrix:
-        platform:
-          - linux/amd64
-          - linux/arm64
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-
-      - uses: docker/setup-buildx-action@v3
-
-      - uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Check tag consistency
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        run: |
-          version=$(grep "version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
-          if [ "${{ fromJson(inputs.plan).announcement_tag }}" != "${version}" ]; then
-            echo "The input tag does not match the version from pyproject.toml:" >&2
-            echo "${{ fromJson(inputs.plan).announcement_tag }}" >&2
-            echo "${version}" >&2
-            exit 1
-          else
-            echo "Releasing ${version}"
-          fi
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Defining this makes sure the org.opencontainers.image.version OCI label becomes the actual release version and not the branch name
-          tags: |
-            type=raw,value=dry-run,enable=${{ inputs.plan == '' || fromJson(inputs.plan).announcement_tag_is_implicit }}
-            type=pep440,pattern={{ version }},value=${{ inputs.plan != '' && fromJson(inputs.plan).announcement_tag || 'dry-run' }},enable=${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-
-      - name: Normalize Platform Pair (replace / with -)
-        run: |
-          platform=${{ matrix.platform }}
-          echo "PLATFORM_TUPLE=${platform//\//-}" >> $GITHUB_ENV
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Build and push by digest
-        id: build
-        uses: docker/build-push-action@v6
-        with:
-          context: .
-          platforms: ${{ matrix.platform }}
-          cache-from: type=gha,scope=ruff-${{ env.PLATFORM_TUPLE }}
-          cache-to: type=gha,mode=min,scope=ruff-${{ env.PLATFORM_TUPLE }}
-          labels: ${{ steps.meta.outputs.labels }}
-          outputs: type=image,name=${{ env.RUFF_BASE_IMG }},push-by-digest=true,name-canonical=true,push=${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-
-      - name: Export digests
-        run: |
-          mkdir -p /tmp/digests
-          digest="${{ steps.build.outputs.digest }}"
-          touch "/tmp/digests/${digest#sha256:}"
-
-      - name: Upload digests
-        uses: actions/upload-artifact@v4
-        with:
-          name: digests-${{ env.PLATFORM_TUPLE }}
-          path: /tmp/digests/*
-          if-no-files-found: error
-          retention-days: 1
-
-  docker-publish:
-    name: Publish Docker image (ghcr.io/astral-sh/ruff)
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-build
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    steps:
-      - name: Download digests
-        uses: actions/download-artifact@v4
-        with:
-          path: /tmp/digests
-          pattern: digests-*
-          merge-multiple: true
-
-      - uses: docker/setup-buildx-action@v3
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          tags: |
-            type=pep440,pattern={{ version }},value=${{ fromJson(inputs.plan).announcement_tag }}
-            type=pep440,pattern={{ major }}.{{ minor }},value=${{ fromJson(inputs.plan).announcement_tag }}
-
-      - uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Create manifest list and push
-        working-directory: /tmp/digests
-        # The jq command expands the docker/metadata json "tags" array entry to `-t tag1 -t tag2 ...` for each tag in the array
-        # The printf will expand the base image with the `<RUFF_BASE_IMG>@sha256:<sha256> ...` for each sha256 in the directory
-        # The final command becomes `docker buildx imagetools create -t tag1 -t tag2 ... <RUFF_BASE_IMG>@sha256:<sha256_1> <RUFF_BASE_IMG>@sha256:<sha256_2> ...`
-        run: |
-          docker buildx imagetools create \
-            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)
-
-  docker-publish-extra:
-    name: Publish additional Docker image based on ${{ matrix.image-mapping }}
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-publish
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    strategy:
-      fail-fast: false
-      matrix:
-        # Mapping of base image followed by a comma followed by one or more base tags (comma separated)
-        # Note, org.opencontainers.image.version label will use the first base tag (use the most specific tag first)
-        image-mapping:
-          - alpine:3.20,alpine3.20,alpine
-          - debian:bookworm-slim,bookworm-slim,debian-slim
-          - buildpack-deps:bookworm,bookworm,debian
-    steps:
-      - uses: docker/setup-buildx-action@v3
-
-      - uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Generate Dynamic Dockerfile Tags
-        shell: bash
-        run: |
-          set -euo pipefail
-
-          # Extract the image and tags from the matrix variable
-          IFS=',' read -r BASE_IMAGE BASE_TAGS <<< "${{ matrix.image-mapping }}"
-
-          # Generate Dockerfile content
-          cat <<EOF > Dockerfile
-          FROM ${BASE_IMAGE}
-          COPY --from=${{ env.RUFF_BASE_IMG }}:latest /ruff /usr/local/bin/ruff
-          ENTRYPOINT []
-          CMD ["/usr/local/bin/ruff"]
-          EOF
-
-          # Initialize a variable to store all tag docker metadata patterns
-          TAG_PATTERNS=""
-
-          # Loop through all base tags and append its docker metadata pattern to the list
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          IFS=','; for TAG in ${BASE_TAGS}; do
-            TAG_PATTERNS="${TAG_PATTERNS}type=pep440,pattern={{ version }},suffix=-${TAG},value=${{ fromJson(inputs.plan).announcement_tag }}\n"
-            TAG_PATTERNS="${TAG_PATTERNS}type=pep440,pattern={{ major }}.{{ minor }},suffix=-${TAG},value=${{ fromJson(inputs.plan).announcement_tag }}\n"
-            TAG_PATTERNS="${TAG_PATTERNS}type=raw,value=${TAG}\n"
-          done
-
-          # Remove the trailing newline from the pattern list
-          TAG_PATTERNS="${TAG_PATTERNS%\\n}"
-
-          # Export image cache name
-          echo "IMAGE_REF=${BASE_IMAGE//:/-}" >> $GITHUB_ENV
-
-          # Export tag patterns using the multiline env var syntax
-          {
-            echo "TAG_PATTERNS<<EOF"
-            echo -e "${TAG_PATTERNS}"
-            echo EOF
-          } >> $GITHUB_ENV
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@v5
-        # ghcr.io prefers index level annotations
-        env:
-          DOCKER_METADATA_ANNOTATIONS_LEVELS: index
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          flavor: |
-            latest=false
-          tags: |
-            ${{ env.TAG_PATTERNS }}
-
-      - name: Build and push
-        uses: docker/build-push-action@v6
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          # We do not really need to cache here as the Dockerfile is tiny
-          #cache-from: type=gha,scope=ruff-${{ env.IMAGE_REF }}
-          #cache-to: type=gha,mode=min,scope=ruff-${{ env.IMAGE_REF }}
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          annotations: ${{ steps.meta.outputs.annotations }}
-
-  # This is effectively a duplicate of `docker-publish` to make https://github.com/astral-sh/ruff/pkgs/container/ruff
-  # show the ruff base image first since GitHub always shows the last updated image digests
-  # This works by annotating the original digests (previously non-annotated) which triggers an update to ghcr.io
-  docker-republish:
-    name: Annotate Docker image (ghcr.io/astral-sh/ruff)
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-publish-extra
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    steps:
-      - name: Download digests
-        uses: actions/download-artifact@v4
-        with:
-          path: /tmp/digests
-          pattern: digests-*
-          merge-multiple: true
-
-      - uses: docker/setup-buildx-action@v3
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@v5
-        env:
-          DOCKER_METADATA_ANNOTATIONS_LEVELS: index
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          tags: |
-            type=pep440,pattern={{ version }},value=${{ fromJson(inputs.plan).announcement_tag }}
-            type=pep440,pattern={{ major }}.{{ minor }},value=${{ fromJson(inputs.plan).announcement_tag }}
-
-      - uses: docker/login-action@v3
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Create manifest list and push
-        working-directory: /tmp/digests
-        # The readarray part is used to make sure the quoting and special characters are preserved on expansion (e.g. spaces)
-        # The jq command expands the docker/metadata json "tags" array entry to `-t tag1 -t tag2 ...` for each tag in the array
-        # The printf will expand the base image with the `<RUFF_BASE_IMG>@sha256:<sha256> ...` for each sha256 in the directory
-        # The final command becomes `docker buildx imagetools create -t tag1 -t tag2 ... <RUFF_BASE_IMG>@sha256:<sha256_1> <RUFF_BASE_IMG>@sha256:<sha256_2> ...`
-        run: |
-          readarray -t lines <<< "$DOCKER_METADATA_OUTPUT_ANNOTATIONS"; annotations=(); for line in "${lines[@]}"; do annotations+=(--annotation "$line"); done
-          docker buildx imagetools create \
-            "${annotations[@]}" \
-            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ env:
   CARGO_TERM_COLOR: always
   RUSTUP_MAX_RETRIES: 10
   PACKAGE_NAME: ruff
-  PYTHON_VERSION: "3.12"
+  PYTHON_VERSION: "3.11"
 
 jobs:
   determine_changes:
@@ -37,7 +37,7 @@ jobs:
         with:
           fetch-depth: 0
 
-      - uses: tj-actions/changed-files@v45
+      - uses: tj-actions/changed-files@v44
         id: changed
         with:
           files_yaml: |
@@ -59,6 +59,7 @@ jobs:
               - "!crates/ruff_python_formatter/**"
               - "!crates/ruff_formatter/**"
               - "!crates/ruff_dev/**"
+              - "!crates/ruff_shrinking/**"
               - scripts/*
               - python/**
               - .github/workflows/ci.yaml
@@ -111,11 +112,11 @@ jobs:
       - name: "Clippy"
         run: cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
       - name: "Clippy (wasm)"
-        run: cargo clippy -p ruff_wasm -p red_knot_wasm --target wasm32-unknown-unknown --all-features --locked -- -D warnings
+        run: cargo clippy -p ruff_wasm --target wasm32-unknown-unknown --all-features --locked -- -D warnings
 
   cargo-test-linux:
     name: "cargo test (linux)"
-    runs-on: depot-ubuntu-22.04-16
+    runs-on: ubuntu-latest
     needs: determine_changes
     if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
     timeout-minutes: 20
@@ -142,13 +143,6 @@ jobs:
 
       # Check for broken links in the documentation.
       - run: cargo doc --all --no-deps
-        env:
-          RUSTDOCFLAGS: "-D warnings"
-      # Use --document-private-items so that all our doc comments are kept in
-      # sync, not just public items. Eventually we should do this for all
-      # crates; for now add crates here as they are warning-clean to prevent
-      # regression.
-      - run: cargo doc --no-deps -p red_knot_python_semantic -p red_knot -p red_knot_test -p ruff_db --document-private-items
         env:
           # Setting RUSTDOCFLAGS because `cargo doc --check` isn't yet implemented (https://github.com/rust-lang/cargo/issues/10025).
           RUSTDOCFLAGS: "-D warnings"
@@ -157,36 +151,9 @@ jobs:
           name: ruff
           path: target/debug/ruff
 
-  cargo-test-linux-release:
-    name: "cargo test (linux, release)"
-    runs-on: depot-ubuntu-22.04-16
-    needs: determine_changes
-    if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
-    timeout-minutes: 20
-    steps:
-      - uses: actions/checkout@v4
-      - name: "Install Rust toolchain"
-        run: rustup show
-      - name: "Install mold"
-        uses: rui314/setup-mold@v1
-      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-nextest
-      - name: "Install cargo insta"
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-insta
-      - uses: Swatinem/rust-cache@v2
-      - name: "Run tests"
-        shell: bash
-        env:
-          NEXTEST_PROFILE: "ci"
-        run: cargo insta test --release --all-features --unreferenced reject --test-runner nextest
-
   cargo-test-windows:
     name: "cargo test (windows)"
-    runs-on: windows-latest-xlarge
+    runs-on: windows-latest
     needs: determine_changes
     if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
     timeout-minutes: 20
@@ -201,9 +168,6 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - name: "Run tests"
         shell: bash
-        env:
-          # Workaround for <https://github.com/nextest-rs/nextest/issues/1493>.
-          RUSTUP_WINDOWS_PATH_ADD_BIN: 1
         run: |
           cargo nextest run --all-features --profile ci
           cargo test --all-features --doc
@@ -220,74 +184,21 @@ jobs:
         run: rustup target add wasm32-unknown-unknown
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version: 18
           cache: "npm"
           cache-dependency-path: playground/package-lock.json
       - uses: jetli/wasm-pack-action@v0.4.0
-        with:
-          version: v0.13.1
       - uses: Swatinem/rust-cache@v2
-      - name: "Test ruff_wasm"
+      - name: "Run wasm-pack"
         run: |
           cd crates/ruff_wasm
           wasm-pack test --node
-      - name: "Test red_knot_wasm"
-        run: |
-          cd crates/red_knot_wasm
-          wasm-pack test --node
 
-  cargo-build-release:
-    name: "cargo build (release)"
-    runs-on: macos-latest
-    if: ${{ github.ref == 'refs/heads/main' }}
-    timeout-minutes: 20
-    steps:
-      - uses: actions/checkout@v4
-      - name: "Install Rust toolchain"
-        run: rustup show
-      - name: "Install mold"
-        uses: rui314/setup-mold@v1
-      - uses: Swatinem/rust-cache@v2
-      - name: "Build"
-        run: cargo build --release --locked
-
-  cargo-build-msrv:
-    name: "cargo build (msrv)"
+  cargo-fuzz:
+    name: "cargo fuzz"
     runs-on: ubuntu-latest
     needs: determine_changes
     if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
-    timeout-minutes: 20
-    steps:
-      - uses: actions/checkout@v4
-      - uses: SebRollen/toml-action@v1.2.0
-        id: msrv
-        with:
-          file: "Cargo.toml"
-          field: "workspace.package.rust-version"
-      - name: "Install Rust toolchain"
-        run: rustup default ${{ steps.msrv.outputs.value }}
-      - name: "Install mold"
-        uses: rui314/setup-mold@v1
-      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-nextest
-      - name: "Install cargo insta"
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-insta
-      - uses: Swatinem/rust-cache@v2
-      - name: "Run tests"
-        shell: bash
-        env:
-          NEXTEST_PROFILE: "ci"
-        run: cargo +${{ steps.msrv.outputs.value }} insta test --all-features --unreferenced reject --test-runner nextest
-
-  cargo-fuzz-build:
-    name: "cargo fuzz build"
-    runs-on: ubuntu-latest
-    needs: determine_changes
-    if: ${{ github.ref == 'refs/heads/main' }}
     timeout-minutes: 10
     steps:
       - uses: actions/checkout@v4
@@ -296,17 +207,14 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "fuzz -> target"
-      - name: "Install cargo-binstall"
-        uses: cargo-bins/cargo-binstall@main
+      - name: "Install cargo-fuzz"
+        uses: taiki-e/install-action@v2
         with:
           tool: cargo-fuzz@0.11.2
-      - name: "Install cargo-fuzz"
-        # Download the latest version from quick install and not the github releases because github releases only has MUSL targets.
-        run: cargo binstall cargo-fuzz --force  --disable-strategies crate-meta-data --no-confirm
       - run: cargo fuzz build -s none
 
   fuzz-parser:
-    name: "fuzz parser"
+    name: "Fuzz the parser"
     runs-on: ubuntu-latest
     needs:
       - cargo-test-linux
@@ -335,7 +243,7 @@ jobs:
           # Make executable, since artifact download doesn't preserve this
           chmod +x ${{ steps.download-cached-binary.outputs.download-path }}/ruff
 
-          python scripts/fuzz-parser/fuzz.py --bin ruff 0-500 --test-executable ${{ steps.download-cached-binary.outputs.download-path }}/ruff
+          python scripts/fuzz-parser/fuzz.py 0-500 --test-executable ${{ steps.download-cached-binary.outputs.download-path }}/ruff
 
   scripts:
     name: "test scripts"
@@ -359,7 +267,7 @@ jobs:
 
   ecosystem:
     name: "ecosystem"
-    runs-on: depot-ubuntu-latest-8
+    runs-on: ubuntu-latest
     needs:
       - cargo-test-linux
       - determine_changes
@@ -380,7 +288,7 @@ jobs:
           name: ruff
           path: target/debug
 
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v3
         name: Download baseline Ruff binary
         with:
           name: ruff
@@ -472,16 +380,22 @@ jobs:
           name: ecosystem-result
           path: ecosystem-result
 
-  cargo-shear:
-    name: "cargo shear"
+  cargo-udeps:
+    name: "cargo udeps"
     runs-on: ubuntu-latest
     needs: determine_changes
     if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
+    timeout-minutes: 20
     steps:
       - uses: actions/checkout@v4
-      - uses: cargo-bins/cargo-binstall@main
-      - run: cargo binstall --no-confirm cargo-shear
-      - run: cargo shear
+      - name: "Install nightly Rust toolchain"
+        # Only pinned to make caching work, update freely
+        run: rustup toolchain install nightly-2023-10-15
+      - uses: Swatinem/rust-cache@v2
+      - name: "Install cargo-udeps"
+        uses: taiki-e/install-action@cargo-udeps
+      - name: "Run cargo-udeps"
+        run: cargo +nightly-2023-10-15 udeps
 
   python-package:
     name: "python package"
@@ -546,8 +460,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
-        with:
-          python-version: "3.13"
       - name: "Add SSH key"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
         uses: webfactory/ssh-agent@v0.9.0
@@ -555,15 +467,13 @@ jobs:
           ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
       - name: "Install Rust toolchain"
         run: rustup show
-      - name: Install uv
-        uses: astral-sh/setup-uv@v3
       - uses: Swatinem/rust-cache@v2
       - name: "Install Insiders dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: uv pip install -r docs/requirements-insiders.txt --system
+        run: pip install -r docs/requirements-insiders.txt
       - name: "Install dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
-        run: uv pip install -r docs/requirements.txt --system
+        run: pip install -r docs/requirements.txt
       - name: "Update README File"
         run: python scripts/transform_readme.py --target mkdocs
       - name: "Generate docs"
@@ -589,12 +499,12 @@ jobs:
         run: rustup show
       - name: "Cache rust"
         uses: Swatinem/rust-cache@v2
-      - name: "Run checks"
+      - name: "Formatter progress"
         run: scripts/formatter_ecosystem_checks.sh
       - name: "Github step summary"
-        run: cat target/formatter-ecosystem/stats.txt > $GITHUB_STEP_SUMMARY
+        run: cat target/progress_projects_stats.txt > $GITHUB_STEP_SUMMARY
       - name: "Remove checkouts from cache"
-        run: rm -r target/formatter-ecosystem
+        run: rm -r target/progress_projects
 
   check-ruff-lsp:
     name: "test ruff-lsp"
@@ -640,7 +550,7 @@ jobs:
           just test
 
   benchmarks:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-latest
     needs: determine_changes
     if: ${{ github.repository == 'astral-sh/ruff' && (needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main') }}
     timeout-minutes: 20
@@ -662,7 +572,7 @@ jobs:
         run: cargo codspeed build --features codspeed -p ruff_benchmark
 
       - name: "Run benchmarks"
-        uses: CodSpeedHQ/action@v3
+        uses: CodSpeedHQ/action@v2
         with:
           run: cargo codspeed run
           token: ${{ secrets.CODSPEED_TOKEN }}

.github/workflows/daily_fuzz.yaml

@@ -1,72 +0,0 @@
-name: Daily parser fuzz
-
-on:
-  workflow_dispatch:
-  schedule:
-    - cron: "0 0 * * *"
-  pull_request:
-    paths:
-      - ".github/workflows/daily_fuzz.yaml"
-
-permissions:
-  contents: read
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
-  cancel-in-progress: true
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-  PACKAGE_NAME: ruff
-  FORCE_COLOR: 1
-
-jobs:
-  fuzz:
-    name: Fuzz
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
-    # Don't run the cron job on forks:
-    if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.12"
-      - name: Install uv
-        run: curl -LsSf https://astral.sh/uv/install.sh | sh
-      - name: Install Python requirements
-        run: uv pip install -r scripts/fuzz-parser/requirements.txt --system
-      - name: "Install Rust toolchain"
-        run: rustup show
-      - name: "Install mold"
-        uses: rui314/setup-mold@v1
-      - uses: Swatinem/rust-cache@v2
-      - name: Build ruff
-        # A debug build means the script runs slower once it gets started,
-        # but this is outweighed by the fact that a release build takes *much* longer to compile in CI
-        run: cargo build --locked
-      - name: Fuzz
-        run: python scripts/fuzz-parser/fuzz.py --bin ruff $(shuf -i 0-9999999999999999999 -n 1000) --test-executable target/debug/ruff
-
-  create-issue-on-failure:
-    name: Create an issue if the daily fuzz surfaced any bugs
-    runs-on: ubuntu-latest
-    needs: fuzz
-    if: ${{ github.repository == 'astral-sh/ruff' && always() && github.event_name == 'schedule' && needs.fuzz.result == 'failure' }}
-    permissions:
-      issues: write
-    steps:
-      - uses: actions/github-script@v7
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            await github.rest.issues.create({
-              owner: "astral-sh",
-              repo: "ruff",
-              title: `Daily parser fuzz failed on ${new Date().toDateString()}`,
-              body: "Runs listed here: https://github.com/astral-sh/ruff/actions/workflows/daily_fuzz.yml",
-              labels: ["bug", "parser", "fuzzer"],
-            })

.github/workflows/docs.yaml

@@ -0,0 +1,55 @@
+name: mkdocs
+
+on:
+  workflow_dispatch:
+    inputs:
+      ref:
+        description: "The commit SHA, tag, or branch to publish. Uses the default branch if not specified."
+        default: ""
+        type: string
+  release:
+    types: [published]
+
+jobs:
+  mkdocs:
+    runs-on: ubuntu-latest
+    env:
+      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
+      MKDOCS_INSIDERS_SSH_KEY_EXISTS: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY != '' }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.ref }}
+      - uses: actions/setup-python@v5
+      - name: "Add SSH key"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        uses: webfactory/ssh-agent@v0.9.0
+        with:
+          ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
+      - name: "Install Rust toolchain"
+        run: rustup show
+      - uses: Swatinem/rust-cache@v2
+      - name: "Install Insiders dependencies"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        run: pip install -r docs/requirements-insiders.txt
+      - name: "Install dependencies"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
+        run: pip install -r docs/requirements.txt
+      - name: "Copy README File"
+        run: |
+          python scripts/transform_readme.py --target mkdocs
+          python scripts/generate_mkdocs.py
+      - name: "Build Insiders docs"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        run: mkdocs build --strict -f mkdocs.insiders.yml
+      - name: "Build docs"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
+        run: mkdocs build --strict -f mkdocs.public.yml
+      - name: "Deploy to Cloudflare Pages"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        uses: cloudflare/wrangler-action@v3.4.1
+        with:
+          apiToken: ${{ secrets.CF_API_TOKEN }}
+          accountId: ${{ secrets.CF_ACCOUNT_ID }}
+          # `github.head_ref` is only set during pull requests and for manual runs or tags we use `main` to deploy to production
+          command: pages deploy site --project-name=astral-docs --branch ${{ github.head_ref || 'main' }} --commit-hash ${GITHUB_SHA}

.github/workflows/notify-dependents.yml

@@ -1,29 +0,0 @@
-# Notify downstream repositories of a new release.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
-name: "[ruff] Notify dependents"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  update-dependents:
-    name: Notify dependents
-    runs-on: ubuntu-latest
-    steps:
-      - name: "Update pre-commit mirror"
-        uses: actions/github-script@v7
-        with:
-          github-token: ${{ secrets.RUFF_PRE_COMMIT_PAT }}
-          script: |
-            github.rest.actions.createWorkflowDispatch({
-              owner: 'astral-sh',
-              repo: 'ruff-pre-commit',
-              workflow_id: 'main.yml',
-              ref: 'main',
-            })

.github/workflows/playground.yaml

@@ -1,16 +1,9 @@
-# Publish the Ruff playground.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
 name: "[Playground] Release"
 
 on:
   workflow_dispatch:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
+  release:
+    types: [published]
 
 env:
   CARGO_INCREMENTAL: 0
@@ -29,7 +22,7 @@ jobs:
         run: rustup target add wasm32-unknown-unknown
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version: 18
           cache: "npm"
           cache-dependency-path: playground/package-lock.json
       - uses: jetli/wasm-pack-action@v0.4.0
@@ -47,7 +40,7 @@ jobs:
         working-directory: playground
       - name: "Deploy to Cloudflare Pages"
         if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@v3.12.1
+        uses: cloudflare/wrangler-action@v3.4.1
         with:
           apiToken: ${{ secrets.CF_API_TOKEN }}
           accountId: ${{ secrets.CF_ACCOUNT_ID }}

.github/workflows/pr-comment.yaml

@@ -17,13 +17,12 @@ jobs:
   comment:
     runs-on: ubuntu-latest
     steps:
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v3
         name: Download pull request number
         with:
           name: pr-number
           run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
           if_no_artifact_found: ignore
-          allow_forks: true
 
       - name: Parse pull request number
         id: pr-number
@@ -33,7 +32,7 @@ jobs:
             echo "pr-number=$(<pr-number)" >> $GITHUB_OUTPUT
           fi
 
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v3
         name: "Download ecosystem results"
         id: download-ecosystem-result
         if: steps.pr-number.outputs.pr-number
@@ -44,20 +43,11 @@ jobs:
           path: pr/ecosystem
           workflow_conclusion: completed
           if_no_artifact_found: ignore
-          allow_forks: true
 
       - name: Generate comment content
         id: generate-comment
         if: steps.download-ecosystem-result.outputs.found_artifact == 'true'
         run: |
-          # Guard against malicious ecosystem results that symlink to a secret
-          # file on this runner
-          if [[ -L pr/ecosystem/ecosystem-result ]]
-          then
-              echo "Error: ecosystem-result cannot be a symlink"
-              exit 1
-          fi
-
           # Note this identifier is used to find the comment to update on
           # subsequent runs
           echo '<!-- generated-comment ecosystem -->' >> comment.txt

.github/workflows/publish-docs.yml

@@ -1,152 +0,0 @@
-# Publish the Ruff documentation.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
-name: mkdocs
-
-on:
-  workflow_dispatch:
-    inputs:
-      ref:
-        description: "The commit SHA, tag, or branch to publish. Uses the default branch if not specified."
-        default: ""
-        type: string
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  mkdocs:
-    runs-on: ubuntu-latest
-    env:
-      MKDOCS_INSIDERS_SSH_KEY_EXISTS: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY != '' }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          ref: ${{ inputs.ref }}
-
-      - uses: actions/setup-python@v5
-        with:
-          python-version: 3.12
-
-      - name: "Set docs version"
-        run: |
-          version="${{ (inputs.plan != '' && fromJson(inputs.plan).announcement_tag) || inputs.ref }}"
-          # if version is missing, use 'latest'
-          if [ -z "$version" ]; then
-            echo "Using 'latest' as version"
-            version="latest"
-          fi
-
-          # Use version as display name for now
-          display_name="$version"
-
-          echo "version=$version" >> $GITHUB_ENV
-          echo "display_name=$display_name" >> $GITHUB_ENV
-
-      - name: "Set branch name"
-        run: |
-          version="${{ env.version }}"
-          display_name="${{ env.display_name }}"
-          timestamp="$(date +%s)"
-
-          # create branch_display_name from display_name by replacing all
-          # characters disallowed in git branch names with hyphens
-          branch_display_name="$(echo "$display_name" | tr -c '[:alnum:]._' '-' | tr -s '-')"
-
-          echo "branch_name=update-docs-$branch_display_name-$timestamp" >> $GITHUB_ENV
-          echo "timestamp=$timestamp" >> $GITHUB_ENV
-
-      - name: "Add SSH key"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        uses: webfactory/ssh-agent@v0.9.0
-        with:
-          ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
-
-      - name: "Install Rust toolchain"
-        run: rustup show
-
-      - uses: Swatinem/rust-cache@v2
-
-      - name: "Install Insiders dependencies"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: pip install -r docs/requirements-insiders.txt
-
-      - name: "Install dependencies"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
-        run: pip install -r docs/requirements.txt
-
-      - name: "Copy README File"
-        run: |
-          python scripts/transform_readme.py --target mkdocs
-          python scripts/generate_mkdocs.py
-
-      - name: "Build Insiders docs"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: mkdocs build --strict -f mkdocs.insiders.yml
-
-      - name: "Build docs"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
-        run: mkdocs build --strict -f mkdocs.public.yml
-
-      - name: "Clone docs repo"
-        run: |
-          version="${{ env.version }}"
-          git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
-
-      - name: "Copy docs"
-        run: rm -rf astral-docs/site/ruff && mkdir -p astral-docs/site && cp -r site/ruff astral-docs/site/
-
-      - name: "Commit docs"
-        working-directory: astral-docs
-        run: |
-          branch_name="${{ env.branch_name }}"
-
-          git config user.name "astral-docs-bot"
-          git config user.email "176161322+astral-docs-bot@users.noreply.github.com"
-
-          git checkout -b $branch_name
-          git add site/ruff
-          git commit -m "Update ruff documentation for $version"
-
-      - name: "Create Pull Request"
-        working-directory: astral-docs
-        env:
-          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
-        run: |
-          version="${{ env.version }}"
-          display_name="${{ env.display_name }}"
-          branch_name="${{ env.branch_name }}"
-
-          # set the PR title
-          pull_request_title="Update ruff documentation for $display_name"
-
-          # Delete any existing pull requests that are open for this version
-          # by checking against pull_request_title because the new PR will
-          # supersede the old one.
-          gh pr list --state open --json title --jq '.[] | select(.title == "$pull_request_title") | .number' | \
-            xargs -I {} gh pr close {}
-
-          # push the branch to GitHub
-          git push origin $branch_name
-
-          # create the PR
-          gh pr create --base main --head $branch_name \
-            --title "$pull_request_title" \
-            --body "Automated documentation update for $display_name" \
-            --label "documentation"
-
-      - name: "Merge Pull Request"
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        working-directory: astral-docs
-        env:
-          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
-        run: |
-          branch_name="${{ env.branch_name }}"
-
-          # auto-merge the PR if the build was triggered by a release. Manual builds should be reviewed by a human.
-          # give the PR a few seconds to be created before trying to auto-merge it
-          sleep 10
-          gh pr merge --squash $branch_name

.github/workflows/publish-pypi.yml

@@ -1,32 +0,0 @@
-# Publish a release to PyPI.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a publish job
-# within `cargo-dist`.
-name: "[ruff] Publish to PyPI"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  pypi-publish:
-    name: Upload to PyPI
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    permissions:
-      # For PyPI's trusted publishing.
-      id-token: write
-    steps:
-      - name: "Install uv"
-        uses: astral-sh/setup-uv@v3
-      - uses: actions/download-artifact@v4
-        with:
-          pattern: wheels-*
-          path: wheels
-          merge-multiple: true
-      - name: Publish to PyPi
-        run: uv publish -v wheels/*

.github/workflows/publish-wasm.yml

@@ -1,55 +0,0 @@
-# Build and publish ruff-api for wasm.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a publish
-# job within `cargo-dist`.
-name: "Build and publish wasm"
-
-on:
-  workflow_dispatch:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-
-jobs:
-  ruff_wasm:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      id-token: write
-    strategy:
-      matrix:
-        target: [web, bundler, nodejs]
-      fail-fast: false
-    steps:
-      - uses: actions/checkout@v4
-      - name: "Install Rust toolchain"
-        run: rustup target add wasm32-unknown-unknown
-      - uses: jetli/wasm-pack-action@v0.4.0
-      - uses: jetli/wasm-bindgen-action@v0.2.0
-      - name: "Run wasm-pack build"
-        run: wasm-pack build --target ${{ matrix.target }} crates/ruff_wasm
-      - name: "Rename generated package"
-        run: | # Replace the package name w/ jq
-          jq '.name="@astral-sh/ruff-wasm-${{ matrix.target }}"' crates/ruff_wasm/pkg/package.json > /tmp/package.json
-          mv /tmp/package.json crates/ruff_wasm/pkg
-      - run: cp LICENSE crates/ruff_wasm/pkg # wasm-pack does not put the LICENSE file in the pkg
-      - uses: actions/setup-node@v4
-        with:
-          node-version: 20
-          registry-url: "https://registry.npmjs.org"
-      - name: "Publish (dry-run)"
-        if: ${{ inputs.plan == '' || fromJson(inputs.plan).announcement_tag_is_implicit }}
-        run: npm publish --dry-run crates/ruff_wasm/pkg
-      - name: "Publish"
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        run: npm publish --provenance --access public crates/ruff_wasm/pkg
-        env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/release.yaml

@@ -1,23 +1,21 @@
-# Build ruff on all platforms.
-#
-# Generates both wheels (for PyPI) and archived binaries (for GitHub releases).
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a local
-# artifacts job within `cargo-dist`.
-name: "Build binaries"
+name: "[ruff] Release"
 
 on:
-  workflow_call:
+  workflow_dispatch:
     inputs:
-      plan:
-        required: true
+      tag:
+        description: "The version to tag, without the leading 'v'. If omitted, will initiate a dry run (no uploads)."
+        type: string
+      sha:
+        description: "The full sha of the commit to be released. If omitted, the latest commit on the default branch will be used."
+        default: ""
         type: string
   pull_request:
     paths:
-      # When we change pyproject.toml, we want to ensure that the maturin builds still work.
+      # When we change pyproject.toml, we want to ensure that the maturin builds still work
       - pyproject.toml
       # And when we change this workflow itself...
-      - .github/workflows/build-binaries.yml
+      - .github/workflows/release.yaml
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -25,7 +23,6 @@ concurrency:
 
 env:
   PACKAGE_NAME: ruff
-  MODULE_NAME: ruff
   PYTHON_VERSION: "3.11"
   CARGO_INCREMENTAL: 0
   CARGO_NET_RETRY: 10
@@ -34,12 +31,11 @@ env:
 
 jobs:
   sdist:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -53,8 +49,8 @@ jobs:
       - name: "Test sdist"
         run: |
           pip install dist/${{ env.PACKAGE_NAME }}-*.tar.gz --force-reinstall
-          ${{ env.MODULE_NAME }} --help
-          python -m ${{ env.MODULE_NAME }} --help
+          ruff --help
+          python -m ruff --help
       - name: "Upload sdist"
         uses: actions/upload-artifact@v4
         with:
@@ -62,12 +58,11 @@ jobs:
           path: dist
 
   macos-x86_64:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: macos-14
+    runs-on: macos-12
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -79,6 +74,11 @@ jobs:
         with:
           target: x86_64
           args: --release --locked --out dist
+      - name: "Test wheel - x86_64"
+        run: |
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ruff --help
+          python -m ruff --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
@@ -86,29 +86,23 @@ jobs:
           path: dist
       - name: "Archive binary"
         run: |
-          TARGET=x86_64-apple-darwin
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-x86_64-apple-darwin.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/x86_64-apple-darwin/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-macos-x86_64
+          name: binaries-macos-x86_64
           path: |
             *.tar.gz
             *.sha256
 
   macos-aarch64:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: macos-14
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -132,24 +126,18 @@ jobs:
           path: dist
       - name: "Archive binary"
         run: |
-          TARGET=aarch64-apple-darwin
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-aarch64-apple-darwin.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/aarch64-apple-darwin/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-aarch64-apple-darwin
+          name: binaries-aarch64-apple-darwin
           path: |
             *.tar.gz
             *.sha256
 
   windows:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: windows-latest
     strategy:
       matrix:
@@ -163,7 +151,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -175,16 +163,13 @@ jobs:
         with:
           target: ${{ matrix.platform.target }}
           args: --release --locked --out dist
-        env:
-          # aarch64 build fails, see https://github.com/PyO3/maturin/issues/2110
-          XWIN_VERSION: 16
       - name: "Test wheel"
         if: ${{ !startsWith(matrix.platform.target, 'aarch64') }}
         shell: bash
         run: |
           python -m pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
-          ${{ env.MODULE_NAME }} --help
-          python -m ${{ env.MODULE_NAME }} --help
+          ruff --help
+          python -m ruff --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
@@ -193,19 +178,18 @@ jobs:
       - name: "Archive binary"
         shell: bash
         run: |
-          ARCHIVE_FILE=ruff-${{ matrix.platform.target }}.zip
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.zip
           7z a $ARCHIVE_FILE ./target/${{ matrix.platform.target }}/release/ruff.exe
           sha256sum $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.platform.target }}
+          name: binaries-${{ matrix.platform.target }}
           path: |
             *.zip
             *.sha256
 
   linux:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -215,7 +199,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -232,36 +216,27 @@ jobs:
         if: ${{ startsWith(matrix.target, 'x86_64') }}
         run: |
           pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
-          ${{ env.MODULE_NAME }} --help
-          python -m ${{ env.MODULE_NAME }} --help
+          ruff --help
+          python -m ruff --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
           name: wheels-${{ matrix.target }}
           path: dist
       - name: "Archive binary"
-        shell: bash
         run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.target }}/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.target }}
+          name: binaries-${{ matrix.target }}
           path: |
             *.tar.gz
             *.sha256
 
   linux-cross:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -283,13 +258,11 @@ jobs:
             arch: ppc64
             # see https://github.com/astral-sh/ruff/issues/10073
             maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
-          - target: arm-unknown-linux-musleabihf
-            arch: arm
 
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -306,8 +279,8 @@ jobs:
         if: matrix.platform.arch != 'ppc64'
         name: Test wheel
         with:
-          arch: ${{ matrix.platform.arch == 'arm' && 'armv6' || matrix.platform.arch }}
-          distro: ${{ matrix.platform.arch == 'arm' && 'bullseye' || 'ubuntu20.04' }}
+          arch: ${{ matrix.platform.arch }}
+          distro: ubuntu20.04
           githubToken: ${{ github.token }}
           install: |
             apt-get update
@@ -322,28 +295,19 @@ jobs:
           name: wheels-${{ matrix.platform.target }}
           path: dist
       - name: "Archive binary"
-        shell: bash
         run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.platform.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.platform.target }}/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.platform.target }}
+          name: binaries-${{ matrix.platform.target }}
           path: |
             *.tar.gz
             *.sha256
 
   musllinux:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -353,7 +317,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -376,35 +340,26 @@ jobs:
             apk add python3
             python -m venv .venv
             .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
-            .venv/bin/${{ env.MODULE_NAME }} --help
+            .venv/bin/ruff check --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
           name: wheels-${{ matrix.target }}
           path: dist
       - name: "Archive binary"
-        shell: bash
         run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.target }}/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.target }}
+          name: binaries-${{ matrix.target }}
           path: |
             *.tar.gz
             *.sha256
 
   musllinux-cross:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -418,7 +373,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          submodules: recursive
+          ref: ${{ inputs.sha }}
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
@@ -442,29 +397,204 @@ jobs:
           run: |
             python -m venv .venv
             .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
-            .venv/bin/${{ env.MODULE_NAME }} --help
+            .venv/bin/ruff check --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
           name: wheels-${{ matrix.platform.target }}
           path: dist
       - name: "Archive binary"
-        shell: bash
         run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.platform.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.platform.target }}/release ruff
           shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
       - name: "Upload binary"
         uses: actions/upload-artifact@v4
         with:
-          name: artifacts-${{ matrix.platform.target }}
+          name: binaries-${{ matrix.platform.target }}
           path: |
             *.tar.gz
             *.sha256
+
+  validate-tag:
+    name: Validate tag
+    runs-on: ubuntu-latest
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main # We checkout the main branch to check for the commit
+      - name: Check main branch
+        if: ${{ inputs.sha }}
+        run: |
+          # Fetch the main branch since a shallow checkout is used by default
+          git fetch origin main --unshallow
+          if ! git branch --contains ${{ inputs.sha }} | grep -E '(^|\s)main$'; then
+            echo "The specified sha is not on the main branch" >&2
+            exit 1
+          fi
+      - name: Check tag consistency
+        run: |
+          # Switch to the commit we want to release
+          git checkout ${{ inputs.sha }}
+          version=$(grep "version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
+          if [ "${{ inputs.tag }}" != "${version}" ]; then
+            echo "The input tag does not match the version from pyproject.toml:" >&2
+            echo "${{ inputs.tag }}" >&2
+            echo "${version}" >&2
+            exit 1
+          else
+            echo "Releasing ${version}"
+          fi
+
+  upload-release:
+    name: Upload to PyPI
+    runs-on: ubuntu-latest
+    needs:
+      - macos-aarch64
+      - macos-x86_64
+      - windows
+      - linux
+      - linux-cross
+      - musllinux
+      - musllinux-cross
+      - validate-tag
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    environment:
+      name: release
+    permissions:
+      # For pypi trusted publishing
+      id-token: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: wheels-*
+          path: wheels
+          merge-multiple: true
+      - name: Publish to PyPi
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          skip-existing: true
+          packages-dir: wheels
+          verbose: true
+
+  tag-release:
+    name: Tag release
+    runs-on: ubuntu-latest
+    needs: upload-release
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    permissions:
+      # For git tag
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - name: git tag
+        run: |
+          git config user.email "hey@astral.sh"
+          git config user.name "Ruff Release CI"
+          git tag -m "v${{ inputs.tag }}" "v${{ inputs.tag }}"
+          # If there is duplicate tag, this will fail. The publish to pypi action will have been a noop (due to skip
+          # existing), so we make a non-destructive exit here
+          git push --tags
+
+  publish-release:
+    name: Publish to GitHub
+    runs-on: ubuntu-latest
+    needs: tag-release
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    permissions:
+      # For GitHub release publishing
+      contents: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: binaries-*
+          path: binaries
+          merge-multiple: true
+      - name: "Publish to GitHub"
+        uses: softprops/action-gh-release@v2
+        with:
+          draft: true
+          files: binaries/*
+          tag_name: v${{ inputs.tag }}
+
+  docker-publish:
+    # This action doesn't need to wait on any other task, it's easy to re-tag if something failed and we're validating
+    # the tag here also
+    name: Push Docker image ghcr.io/astral-sh/ruff
+    runs-on: ubuntu-latest
+    environment:
+      name: release
+    permissions:
+      # For the docker push
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+
+      - uses: docker/setup-buildx-action@v3
+
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/astral-sh/ruff
+
+      - name: Check tag consistency
+        # Unlike validate-tag we don't check if the commit is on the main branch, but it seems good enough since we can
+        # change docker tags
+        if: ${{ inputs.tag }}
+        run: |
+          version=$(grep "version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
+          if [ "${{ inputs.tag }}" != "${version}" ]; then
+            echo "The input tag does not match the version from pyproject.toml:" >&2
+            echo "${{ inputs.tag }}" >&2
+            echo "${version}" >&2
+            exit 1
+          else
+            echo "Releasing ${version}"
+          fi
+
+      - name: "Build and push Docker image"
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          # Reuse the builder
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          push: ${{ inputs.tag != '' }}
+          tags: ghcr.io/astral-sh/ruff:latest,ghcr.io/astral-sh/ruff:${{ inputs.tag || 'dry-run' }}
+          labels: ${{ steps.meta.outputs.labels }}
+
+  # After the release has been published, we update downstream repositories
+  # This is separate because if this fails the release is still fine, we just need to do some manual workflow triggers
+  update-dependents:
+    name: Update dependents
+    runs-on: ubuntu-latest
+    needs: publish-release
+    steps:
+      - name: "Update pre-commit mirror"
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.RUFF_PRE_COMMIT_PAT }}
+          script: |
+            github.rest.actions.createWorkflowDispatch({
+              owner: 'astral-sh',
+              repo: 'ruff-pre-commit',
+              workflow_id: 'main.yml',
+              ref: 'main',
+            })

.github/workflows/release.yml

@@ -1,300 +0,0 @@
-# This file was autogenerated by dist: https://opensource.axo.dev/cargo-dist/
-#
-# Copyright 2022-2024, axodotdev
-# SPDX-License-Identifier: MIT or Apache-2.0
-#
-# CI that:
-#
-# * checks for a Git Tag that looks like a release
-# * builds artifacts with dist (archives, installers, hashes)
-# * uploads those artifacts to temporary workflow zip
-# * on success, uploads the artifacts to a GitHub Release
-#
-# Note that the GitHub Release will be created with a generated
-# title/body based on your changelogs.
-
-name: Release
-permissions:
-  "contents": "write"
-
-# This task will run whenever you workflow_dispatch with a tag that looks like a version
-# like "1.0.0", "v0.1.0-prerelease.1", "my-app/0.1.0", "releases/v1.0.0", etc.
-# Various formats will be parsed into a VERSION and an optional PACKAGE_NAME, where
-# PACKAGE_NAME must be the name of a Cargo package in your workspace, and VERSION
-# must be a Cargo-style SemVer Version (must have at least major.minor.patch).
-#
-# If PACKAGE_NAME is specified, then the announcement will be for that
-# package (erroring out if it doesn't have the given version or isn't dist-able).
-#
-# If PACKAGE_NAME isn't specified, then the announcement will be for all
-# (dist-able) packages in the workspace with that version (this mode is
-# intended for workspaces with only one dist-able package, or with all dist-able
-# packages versioned/released in lockstep).
-#
-# If you push multiple tags at once, separate instances of this workflow will
-# spin up, creating an independent announcement for each one. However, GitHub
-# will hard limit this to 3 tags per commit, as it will assume more tags is a
-# mistake.
-#
-# If there's a prerelease-style suffix to the version, then the release(s)
-# will be marked as a prerelease.
-on:
-  workflow_dispatch:
-    inputs:
-      tag:
-        description: Release Tag
-        required: true
-        default: dry-run
-        type: string
-
-jobs:
-  # Run 'dist plan' (or host) to determine what tasks we need to do
-  plan:
-    runs-on: "ubuntu-20.04"
-    outputs:
-      val: ${{ steps.plan.outputs.manifest }}
-      tag: ${{ (inputs.tag != 'dry-run' && inputs.tag) || '' }}
-      tag-flag: ${{ inputs.tag && inputs.tag != 'dry-run' && format('--tag={0}', inputs.tag) || '' }}
-      publishing: ${{ inputs.tag && inputs.tag != 'dry-run' }}
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-      - name: Install dist
-        # we specify bash to get pipefail; it guards against the `curl` command
-        # failing. otherwise `sh` won't catch that `curl` returned non-0
-        shell: bash
-        run: "curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.25.2-prerelease.3/cargo-dist-installer.sh | sh"
-      - name: Cache dist
-        uses: actions/upload-artifact@v4
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/dist
-      # sure would be cool if github gave us proper conditionals...
-      # so here's a doubly-nested ternary-via-truthiness to try to provide the best possible
-      # functionality based on whether this is a pull_request, and whether it's from a fork.
-      # (PRs run on the *source* but secrets are usually on the *target* -- that's *good*
-      # but also really annoying to build CI around when it needs secrets to work right.)
-      - id: plan
-        run: |
-          dist ${{ (inputs.tag && inputs.tag != 'dry-run' && format('host --steps=create --tag={0}', inputs.tag)) || 'plan' }} --output-format=json > plan-dist-manifest.json
-          echo "dist ran successfully"
-          cat plan-dist-manifest.json
-          echo "manifest=$(jq -c "." plan-dist-manifest.json)" >> "$GITHUB_OUTPUT"
-      - name: "Upload dist-manifest.json"
-        uses: actions/upload-artifact@v4
-        with:
-          name: artifacts-plan-dist-manifest
-          path: plan-dist-manifest.json
-
-  custom-build-binaries:
-    needs:
-      - plan
-    if: ${{ needs.plan.outputs.publishing == 'true' || fromJson(needs.plan.outputs.val).ci.github.pr_run_mode == 'upload' || inputs.tag == 'dry-run' }}
-    uses: ./.github/workflows/build-binaries.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-build-docker:
-    needs:
-      - plan
-    if: ${{ needs.plan.outputs.publishing == 'true' || fromJson(needs.plan.outputs.val).ci.github.pr_run_mode == 'upload' || inputs.tag == 'dry-run' }}
-    uses: ./.github/workflows/build-docker.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    permissions:
-      "contents": "read"
-      "packages": "write"
-
-  # Build and package all the platform-agnostic(ish) things
-  build-global-artifacts:
-    needs:
-      - plan
-      - custom-build-binaries
-      - custom-build-docker
-    runs-on: "ubuntu-20.04"
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      BUILD_MANIFEST_NAME: target/distrib/global-dist-manifest.json
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-      - name: Install cached dist
-        uses: actions/download-artifact@v4
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/
-      - run: chmod +x ~/.cargo/bin/dist
-      # Get all the local artifacts for the global tasks to use (for e.g. checksums)
-      - name: Fetch local artifacts
-        uses: actions/download-artifact@v4
-        with:
-          pattern: artifacts-*
-          path: target/distrib/
-          merge-multiple: true
-      - id: cargo-dist
-        shell: bash
-        run: |
-          dist build ${{ needs.plan.outputs.tag-flag }} --output-format=json "--artifacts=global" > dist-manifest.json
-          echo "dist ran successfully"
-
-          # Parse out what we just built and upload it to scratch storage
-          echo "paths<<EOF" >> "$GITHUB_OUTPUT"
-          jq --raw-output ".upload_files[]" dist-manifest.json >> "$GITHUB_OUTPUT"
-          echo "EOF" >> "$GITHUB_OUTPUT"
-
-          cp dist-manifest.json "$BUILD_MANIFEST_NAME"
-      - name: "Upload artifacts"
-        uses: actions/upload-artifact@v4
-        with:
-          name: artifacts-build-global
-          path: |
-            ${{ steps.cargo-dist.outputs.paths }}
-            ${{ env.BUILD_MANIFEST_NAME }}
-  # Determines if we should publish/announce
-  host:
-    needs:
-      - plan
-      - custom-build-binaries
-      - custom-build-docker
-      - build-global-artifacts
-    # Only run if we're "publishing", and only if local and global didn't fail (skipped is fine)
-    if: ${{ always() && needs.plan.outputs.publishing == 'true' && (needs.build-global-artifacts.result == 'skipped' || needs.build-global-artifacts.result == 'success') && (needs.custom-build-binaries.result == 'skipped' || needs.custom-build-binaries.result == 'success') && (needs.custom-build-docker.result == 'skipped' || needs.custom-build-docker.result == 'success') }}
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    runs-on: "ubuntu-20.04"
-    outputs:
-      val: ${{ steps.host.outputs.manifest }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-      - name: Install cached dist
-        uses: actions/download-artifact@v4
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/
-      - run: chmod +x ~/.cargo/bin/dist
-      # Fetch artifacts from scratch-storage
-      - name: Fetch artifacts
-        uses: actions/download-artifact@v4
-        with:
-          pattern: artifacts-*
-          path: target/distrib/
-          merge-multiple: true
-      # This is a harmless no-op for GitHub Releases, hosting for that happens in "announce"
-      - id: host
-        shell: bash
-        run: |
-          dist host ${{ needs.plan.outputs.tag-flag }} --steps=upload --steps=release --output-format=json > dist-manifest.json
-          echo "artifacts uploaded and released successfully"
-          cat dist-manifest.json
-          echo "manifest=$(jq -c "." dist-manifest.json)" >> "$GITHUB_OUTPUT"
-      - name: "Upload dist-manifest.json"
-        uses: actions/upload-artifact@v4
-        with:
-          # Overwrite the previous copy
-          name: artifacts-dist-manifest
-          path: dist-manifest.json
-
-  custom-publish-pypi:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-pypi.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "id-token": "write"
-      "packages": "write"
-
-  custom-publish-wasm:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-wasm.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "contents": "read"
-      "id-token": "write"
-      "packages": "write"
-
-  # Create a GitHub Release while uploading all files to it
-  announce:
-    needs:
-      - plan
-      - host
-      - custom-publish-pypi
-      - custom-publish-wasm
-    # use "always() && ..." to allow us to wait for all publish jobs while
-    # still allowing individual publish jobs to skip themselves (for prereleases).
-    # "host" however must run to completion, no skipping allowed!
-    if: ${{ always() && needs.host.result == 'success' && (needs.custom-publish-pypi.result == 'skipped' || needs.custom-publish-pypi.result == 'success') && (needs.custom-publish-wasm.result == 'skipped' || needs.custom-publish-wasm.result == 'success') }}
-    runs-on: "ubuntu-20.04"
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-      # Create a GitHub Release while uploading all files to it
-      - name: "Download GitHub Artifacts"
-        uses: actions/download-artifact@v4
-        with:
-          pattern: artifacts-*
-          path: artifacts
-          merge-multiple: true
-      - name: Cleanup
-        run: |
-          # Remove the granular manifests
-          rm -f artifacts/*-dist-manifest.json
-      - name: Create GitHub Release
-        env:
-          PRERELEASE_FLAG: "${{ fromJson(needs.host.outputs.val).announcement_is_prerelease && '--prerelease' || '' }}"
-          ANNOUNCEMENT_TITLE: "${{ fromJson(needs.host.outputs.val).announcement_title }}"
-          ANNOUNCEMENT_BODY: "${{ fromJson(needs.host.outputs.val).announcement_github_body }}"
-          RELEASE_COMMIT: "${{ github.sha }}"
-        run: |
-          # Write and read notes from a file to avoid quoting breaking things
-          echo "$ANNOUNCEMENT_BODY" > $RUNNER_TEMP/notes.txt
-
-          gh release create "${{ needs.plan.outputs.tag }}" --target "$RELEASE_COMMIT" $PRERELEASE_FLAG --title "$ANNOUNCEMENT_TITLE" --notes-file "$RUNNER_TEMP/notes.txt" artifacts/*
-
-  custom-notify-dependents:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/notify-dependents.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-publish-docs:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/publish-docs.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-publish-playground:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/publish-playground.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit

.github/workflows/sync_typeshed.yaml

@@ -1,80 +0,0 @@
-name: Sync typeshed
-
-on:
-  workflow_dispatch:
-  schedule:
-    # Run on the 1st and the 15th of every month:
-    - cron: "0 0 1,15 * *"
-
-env:
-  FORCE_COLOR: 1
-  GH_TOKEN: ${{ github.token }}
-
-jobs:
-  sync:
-    name: Sync typeshed
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
-    # Don't run the cron job on forks:
-    if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
-    permissions:
-      contents: write
-      pull-requests: write
-    steps:
-      - uses: actions/checkout@v4
-        name: Checkout Ruff
-        with:
-          path: ruff
-      - uses: actions/checkout@v4
-        name: Checkout typeshed
-        with:
-          repository: python/typeshed
-          path: typeshed
-      - name: Setup git
-        run: |
-          git config --global user.name typeshedbot
-          git config --global user.email '<>'
-      - name: Sync typeshed
-        id: sync
-        run: |
-          rm -rf ruff/crates/red_knot_vendored/vendor/typeshed
-          mkdir ruff/crates/red_knot_vendored/vendor/typeshed
-          cp typeshed/README.md ruff/crates/red_knot_vendored/vendor/typeshed
-          cp typeshed/LICENSE ruff/crates/red_knot_vendored/vendor/typeshed
-          cp -r typeshed/stdlib ruff/crates/red_knot_vendored/vendor/typeshed/stdlib
-          rm -rf ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/@tests
-          git -C typeshed rev-parse HEAD > ruff/crates/red_knot_vendored/vendor/typeshed/source_commit.txt
-      - name: Commit the changes
-        id: commit
-        if: ${{ steps.sync.outcome == 'success' }}
-        run: |
-          cd ruff
-          git checkout -b typeshedbot/sync-typeshed
-          git add .
-          git diff --staged --quiet || git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)"
-      - name: Create a PR
-        if: ${{ steps.sync.outcome == 'success' && steps.commit.outcome == 'success' }}
-        run: |
-          cd ruff
-          git push --force origin typeshedbot/sync-typeshed
-          gh pr list --repo $GITHUB_REPOSITORY --head typeshedbot/sync-typeshed --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
-          gh pr create --title "Sync vendored typeshed stubs" --body "Close and reopen this PR to trigger CI" --label "internal"
-
-  create-issue-on-failure:
-    name: Create an issue if the typeshed sync failed
-    runs-on: ubuntu-latest
-    needs: [sync]
-    if: ${{ github.repository == 'astral-sh/ruff' && always() && github.event_name == 'schedule' && needs.sync.result == 'failure' }}
-    permissions:
-      issues: write
-    steps:
-      - uses: actions/github-script@v7
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            await github.rest.issues.create({
-              owner: "astral-sh",
-              repo: "ruff",
-              title: `Automated typeshed sync failed on ${new Date().toDateString()}`,
-              body: "Runs are listed here: https://github.com/astral-sh/ruff/actions/workflows/sync_typeshed.yaml",
-            })

.gitignore

@@ -21,14 +21,6 @@ flamegraph.svg
 # `CARGO_TARGET_DIR=target-llvm-lines RUSTFLAGS="-Csymbol-mangling-version=v0" cargo llvm-lines -p ruff --lib`
 /target*
 
-# samply profiles
-profile.json
-
-# tracing-flame traces
-tracing.folded
-tracing-flamechart.svg
-tracing-flamegraph.svg
-
 ###
 # Rust.gitignore
 ###

.markdownlint.yaml

@@ -14,9 +14,6 @@ MD041: false
 # MD013/line-length
 MD013: false
 
-# MD014/commands-show-output
-MD014: false
-
 # MD024/no-duplicate-heading
 MD024:
   # Allow when nested under different parents e.g. CHANGELOG.md

.pre-commit-config.yaml

@@ -1,13 +1,9 @@
-fail_fast: false
+fail_fast: true
 
 exclude: |
   (?x)^(
-    crates/red_knot_vendored/vendor/.*|
-    crates/red_knot_workspace/resources/.*|
     crates/ruff_linter/resources/.*|
     crates/ruff_linter/src/rules/.*/snapshots/.*|
-    crates/ruff_notebook/resources/.*|
-    crates/ruff_server/resources/.*|
     crates/ruff/resources/.*|
     crates/ruff_python_formatter/resources/.*|
     crates/ruff_python_formatter/tests/snapshots/.*|
@@ -17,18 +13,17 @@ exclude: |
 
 repos:
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.23
+    rev: v0.16
     hooks:
       - id: validate-pyproject
 
   - repo: https://github.com/executablebooks/mdformat
-    rev: 0.7.18
+    rev: 0.7.17
     hooks:
       - id: mdformat
         additional_dependencies:
           - mdformat-mkdocs
           - mdformat-admon
-          - mdformat-footnote
         exclude: |
           (?x)^(
             docs/formatter/black\.md
@@ -36,7 +31,7 @@ repos:
           )$
 
   - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.42.0
+    rev: v0.39.0
     hooks:
       - id: markdownlint-fix
         exclude: |
@@ -45,21 +40,8 @@ repos:
             | docs/\w+\.md
           )$
 
-  - repo: https://github.com/adamchainz/blacken-docs
-    rev: 1.19.1
-    hooks:
-      - id: blacken-docs
-        args: ["--pyi", "--line-length", "130"]
-        files: '^crates/.*/resources/mdtest/.*\.md'
-        exclude: |
-          (?x)^(
-            .*?invalid(_.+)*_syntax\.md
-          )$
-        additional_dependencies:
-          - black==24.10.0
-
   - repo: https://github.com/crate-ci/typos
-    rev: v1.27.3
+    rev: v1.20.9
     hooks:
       - id: typos
 
@@ -73,17 +55,22 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.7.4
+    rev: v0.4.1
     hooks:
       - id: ruff-format
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
         types_or: [python, pyi]
         require_serial: true
+        exclude: |
+          (?x)^(
+            crates/ruff_linter/resources/.*|
+            crates/ruff_python_formatter/resources/.*
+          )$
 
   # Prettier
-  - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.3.3
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v3.1.0
     hooks:
       - id: prettier
         types: [yaml]

.prettierignore

@@ -1,2 +0,0 @@
-# Auto-generated by `cargo-dist`.
-.github/workflows/release.yml

.vscode/extensions.json

@@ -1,5 +0,0 @@
-{
-    "recommendations": [
-        "rust-lang.rust-analyzer"
-    ]
-}

.vscode/settings.json

@@ -1,6 +0,0 @@
-{
-    "rust-analyzer.check.extraArgs": [
-        "--all-features"
-    ],
-    "rust-analyzer.check.command": "clippy",
-}

BREAKING_CHANGES.md

@@ -1,88 +1,5 @@
 # Breaking Changes
 
-## 0.8.0
-
-- **Default to Python 3.9**
-
-    Ruff now defaults to Python 3.9 instead of 3.8 if no explicit Python version is configured using [`ruff.target-version`](https://docs.astral.sh/ruff/settings/#target-version) or [`project.requires-python`](https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#python-requires) ([#13896](https://github.com/astral-sh/ruff/pull/13896))
-
-- **Changed location of `pydoclint` diagnostics**
-
-    [`pydoclint`](https://docs.astral.sh/ruff/rules/#pydoclint-doc) diagnostics now point to the first-line of the problematic docstring. Previously, this was not the case.
-
-    If you've opted into these preview rules but have them suppressed using
-    [`noqa`](https://docs.astral.sh/ruff/linter/#error-suppression) comments in
-    some places, this change may mean that you need to move the `noqa` suppression
-    comments. Most users should be unaffected by this change.
-
-- **Use XDG (i.e. `~/.local/bin`) instead of the Cargo home directory in the standalone installer**
-
-    Previously, Ruff's installer used `$CARGO_HOME` or `~/.cargo/bin` for its target install directory. Now, Ruff will be installed into `$XDG_BIN_HOME`, `$XDG_DATA_HOME/../bin`, or `~/.local/bin` (in that order).
-
-    This change is only relevant to users of the standalone Ruff installer (using the shell or PowerShell script). If you installed Ruff using uv or pip, you should be unaffected.
-
-- **Changes to the line width calculation**
-
-    Ruff now uses a new version of the [unicode-width](https://github.com/unicode-rs/unicode-width) Rust crate to calculate the line width. In very rare cases, this may lead to lines containing Unicode characters being reformatted, or being considered too long when they were not before ([`E501`](https://docs.astral.sh/ruff/rules/line-too-long/)).
-
-## 0.7.0
-
-- The pytest rules `PT001` and `PT023` now default to omitting the decorator parentheses when there are no arguments
-    ([#12838](https://github.com/astral-sh/ruff/pull/12838), [#13292](https://github.com/astral-sh/ruff/pull/13292)).
-    This was a change that we attempted to make in Ruff v0.6.0, but only partially made due to an error on our part.
-    See the [blog post](https://astral.sh/blog/ruff-v0.7.0) for more details.
-- The `useless-try-except` rule (in our `tryceratops` category) has been recoded from `TRY302` to
-    `TRY203` ([#13502](https://github.com/astral-sh/ruff/pull/13502)). This ensures Ruff's code is consistent with
-    the same rule in the [`tryceratops`](https://github.com/guilatrova/tryceratops) linter.
-- The `lint.allow-unused-imports` setting has been removed ([#13677](https://github.com/astral-sh/ruff/pull/13677)). Use
-    [`lint.pyflakes.allow-unused-imports`](https://docs.astral.sh/ruff/settings/#lint_pyflakes_allowed-unused-imports)
-    instead.
-
-## 0.6.0
-
-- Detect imports in `src` layouts by default for `isort` rules ([#12848](https://github.com/astral-sh/ruff/pull/12848))
-
-- The pytest rules `PT001` and `PT023` now default to omitting the decorator parentheses when there are no arguments ([#12838](https://github.com/astral-sh/ruff/pull/12838)).
-
-- Lint and format Jupyter Notebook by default ([#12878](https://github.com/astral-sh/ruff/pull/12878)).
-
-    You can disable specific rules for notebooks using [`per-file-ignores`](https://docs.astral.sh/ruff/settings/#lint_per-file-ignores):
-
-    ```toml
-    [tool.ruff.lint.per-file-ignores]
-    "*.ipynb" = ["E501"] # disable line-too-long in notebooks
-    ```
-
-    If you'd prefer to either only lint or only format Jupyter Notebook files, you can use the
-    section-specific `exclude` option to do so. For example, the following would only lint Jupyter
-    Notebook files and not format them:
-
-    ```toml
-    [tool.ruff.format]
-    exclude = ["*.ipynb"]
-    ```
-
-    And, conversely, the following would only format Jupyter Notebook files and not lint them:
-
-    ```toml
-    [tool.ruff.lint]
-    exclude = ["*.ipynb"]
-    ```
-
-    You can completely disable Jupyter Notebook support by updating the [`extend-exclude`](https://docs.astral.sh/ruff/settings/#extend-exclude) setting:
-
-    ```toml
-    [tool.ruff]
-    extend-exclude = ["*.ipynb"]
-    ```
-
-## 0.5.0
-
-- Follow the XDG specification to discover user-level configurations on macOS (same as on other Unix platforms)
-- Selecting `ALL` now excludes deprecated rules
-- The released archives now include an extra level of nesting, which can be removed with `--strip-components=1` when untarring.
-- The release artifact's file name no longer includes the version tag. This enables users to install via `/latest` URLs on GitHub.
-
 ## 0.3.0
 
 ### Ruff 2024.2 style

CONTRIBUTING.md

@@ -2,6 +2,35 @@
 
 Welcome! We're happy to have you here. Thank you in advance for your contribution to Ruff.
 
+- [The Basics](#the-basics)
+    - [Prerequisites](#prerequisites)
+    - [Development](#development)
+    - [Project Structure](#project-structure)
+    - [Example: Adding a new lint rule](#example-adding-a-new-lint-rule)
+        - [Rule naming convention](#rule-naming-convention)
+        - [Rule testing: fixtures and snapshots](#rule-testing-fixtures-and-snapshots)
+    - [Example: Adding a new configuration option](#example-adding-a-new-configuration-option)
+- [MkDocs](#mkdocs)
+- [Release Process](#release-process)
+    - [Creating a new release](#creating-a-new-release)
+- [Ecosystem CI](#ecosystem-ci)
+- [Benchmarking and Profiling](#benchmarking-and-profiling)
+    - [CPython Benchmark](#cpython-benchmark)
+    - [Microbenchmarks](#microbenchmarks)
+        - [Benchmark-driven Development](#benchmark-driven-development)
+        - [PR Summary](#pr-summary)
+        - [Tips](#tips)
+    - [Profiling Projects](#profiling-projects)
+        - [Linux](#linux)
+        - [Mac](#mac)
+- [`cargo dev`](#cargo-dev)
+- [Subsystems](#subsystems)
+    - [Compilation Pipeline](#compilation-pipeline)
+    - [Import Categorization](#import-categorization)
+        - [Project root](#project-root)
+        - [Package root](#package-root)
+        - [Import categorization](#import-categorization-1)
+
 ## The Basics
 
 Ruff welcomes contributions in the form of pull requests.
@@ -29,14 +58,16 @@ You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
 cargo install cargo-insta
 ```
 
-You'll need [uv](https://docs.astral.sh/uv/getting-started/installation/) (or `pipx` and `pip`) to
-run Python utility commands.
+And you'll need pre-commit to run some validation checks:
+
+```shell
+pipx install pre-commit  # or `pip install pre-commit` if you have a virtualenv
+```
 
 You can optionally install pre-commit hooks to automatically run the validation checks
 when making a commit:
 
 ```shell
-uv tool install pre-commit
 pre-commit install
 ```
 
@@ -64,14 +95,12 @@ and that it passes both the lint and test validation checks:
 ```shell
 cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
 RUFF_UPDATE_SCHEMA=1 cargo test  # Rust testing and updating ruff.schema.json
-uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
 ```
 
 These checks will run on GitHub Actions when you open your pull request, but running them locally
 will save you time and expedite the merge process.
 
-If you're using VS Code, you can also install the recommended [rust-analyzer](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer) extension to get these checks while editing.
-
 Note that many code changes also require updating the snapshot tests, which is done interactively
 after running `cargo test` like so:
 
@@ -249,7 +278,7 @@ These represent, respectively: the schema used to parse the `pyproject.toml` fil
 intermediate representation; and the final, internal representation used to power Ruff.
 
 To add a new configuration option, you'll likely want to modify these latter few files (along with
-`args.rs`, if appropriate). If you want to pattern-match against an existing example, grep for
+`arg.rs`, if appropriate). If you want to pattern-match against an existing example, grep for
 `dummy_variable_rgx`, which defines a regular expression to match against acceptable unused
 variables (e.g., `_`).
 
@@ -265,20 +294,26 @@ To preview any changes to the documentation locally:
 
 1. Install the [Rust toolchain](https://www.rust-lang.org/tools/install).
 
+1. Install MkDocs and Material for MkDocs with:
+
+    ```shell
+    pip install -r docs/requirements.txt
+    ```
+
 1. Generate the MkDocs site with:
 
     ```shell
-    uv run --no-project --isolated --with-requirements docs/requirements.txt scripts/generate_mkdocs.py
+    python scripts/generate_mkdocs.py
     ```
 
 1. Run the development server with:
 
     ```shell
     # For contributors.
-    uvx --with-requirements docs/requirements.txt -- mkdocs serve -f mkdocs.public.yml
+    mkdocs serve -f mkdocs.public.yml
 
     # For members of the Astral org, which has access to MkDocs Insiders via sponsorship.
-    uvx --with-requirements docs/requirements-insiders.txt -- mkdocs serve -f mkdocs.insiders.yml
+    mkdocs serve -f mkdocs.insiders.yml
     ```
 
 The documentation should then be available locally at
@@ -296,63 +331,41 @@ even patch releases may contain [non-backwards-compatible changes](https://semve
 ### Creating a new release
 
 1. Install `uv`: `curl -LsSf https://astral.sh/uv/install.sh | sh`
-
-1. Run `./scripts/release.sh`; this command will:
-
+1. Run `./scripts/release/bump.sh`; this command will:
     - Generate a temporary virtual environment with `rooster`
     - Generate a changelog entry in `CHANGELOG.md`
     - Update versions in `pyproject.toml` and `Cargo.toml`
     - Update references to versions in the `README.md` and documentation
     - Display contributors for the release
-
 1. The changelog should then be editorialized for consistency
-
     - Often labels will be missing from pull requests they will need to be manually organized into the proper section
     - Changes should be edited to be user-facing descriptions, avoiding internal details
-
 1. Highlight any breaking changes in `BREAKING_CHANGES.md`
-
 1. Run `cargo check`. This should update the lock file with new versions.
-
 1. Create a pull request with the changelog and version updates
-
 1. Merge the PR
-
-1. Run the [release workflow](https://github.com/astral-sh/ruff/actions/workflows/release.yml) with:
-
+1. Run the [release workflow](https://github.com/astral-sh/ruff/actions/workflows/release.yaml) with:
     - The new version number (without starting `v`)
-
+    - The commit hash of the merged release pull request on `main`
 1. The release workflow will do the following:
-
     1. Build all the assets. If this fails (even though we tested in step 4), we haven't tagged or
-        uploaded anything, you can restart after pushing a fix. If you just need to rerun the build,
-        make sure you're [re-running all the failed
-        jobs](https://docs.github.com/en/actions/managing-workflow-runs/re-running-workflows-and-jobs#re-running-failed-jobs-in-a-workflow) and not just a single failed job.
+        uploaded anything, you can restart after pushing a fix.
     1. Upload to PyPI.
     1. Create and push the Git tag (as extracted from `pyproject.toml`). We create the Git tag only
         after building the wheels and uploading to PyPI, since we can't delete or modify the tag ([#4468](https://github.com/astral-sh/ruff/issues/4468)).
     1. Attach artifacts to draft GitHub release
     1. Trigger downstream repositories. This can fail non-catastrophically, as we can run any
         downstream jobs manually if needed.
-
-1. Verify the GitHub release:
-
-    1. The Changelog should match the content of `CHANGELOG.md`
-    1. Append the contributors from the `scripts/release.sh` script
-
+1. Publish the GitHub release
+    1. Open the draft release in the GitHub release section
+    1. Copy the changelog for the release into the GitHub release
+        - See previous releases for formatting of section headers
+    1. Append the contributors from the `bump.sh` script
 1. If needed, [update the schemastore](https://github.com/astral-sh/ruff/blob/main/scripts/update_schemastore.py).
-
     1. One can determine if an update is needed when
         `git diff old-version-tag new-version-tag -- ruff.schema.json` returns a non-empty diff.
     1. Once run successfully, you should follow the link in the output to create a PR.
-
-1. If needed, update the [`ruff-lsp`](https://github.com/astral-sh/ruff-lsp) and
-    [`ruff-vscode`](https://github.com/astral-sh/ruff-vscode) repositories and follow
-    the release instructions in those repositories. `ruff-lsp` should always be updated
-    before `ruff-vscode`.
-
-    This step is generally not required for a patch release, but should always be done
-    for a minor release.
+1. If needed, update the `ruff-lsp` and `ruff-vscode` repositories.
 
 ## Ecosystem CI
 
@@ -360,8 +373,9 @@ GitHub Actions will run your changes against a number of real-world projects fro
 report on any linter or formatter differences. You can also run those checks locally via:
 
 ```shell
-uvx --from ./python/ruff-ecosystem ruff-ecosystem check ruff "./target/debug/ruff"
-uvx --from ./python/ruff-ecosystem ruff-ecosystem format ruff "./target/debug/ruff"
+pip install -e ./python/ruff-ecosystem
+ruff-ecosystem check ruff "./target/debug/ruff"
+ruff-ecosystem format ruff "./target/debug/ruff"
 ```
 
 See the [ruff-ecosystem package](https://github.com/astral-sh/ruff/tree/main/python/ruff-ecosystem) for more details.
@@ -374,7 +388,7 @@ We have several ways of benchmarking and profiling Ruff:
 - Microbenchmarks which run the linter or the formatter on individual files. These run on pull requests.
 - Profiling the linter on either the microbenchmarks or entire projects
 
-> **Note**
+> \[!NOTE\]
 > When running benchmarks, ensure that your CPU is otherwise idle (e.g., close any background
 > applications, like web browsers). You may also want to switch your CPU to a "performance"
 > mode, if it exists, especially when benchmarking short-lived processes.
@@ -388,18 +402,12 @@ which makes it a good target for benchmarking.
 git clone --branch 3.10 https://github.com/python/cpython.git crates/ruff_linter/resources/test/cpython
 ```
 
-Install `hyperfine`:
-
-```shell
-cargo install hyperfine
-```
-
 To benchmark the release build:
 
 ```shell
 cargo build --release && hyperfine --warmup 10 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ -e"
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ -e"
 
 Benchmark 1: ./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache
   Time (mean ± σ):     293.8 ms ±   3.2 ms    [User: 2384.6 ms, System: 90.3 ms]
@@ -418,7 +426,7 @@ To benchmark against the ecosystem's existing tools:
 
 ```shell
 hyperfine --ignore-failure --warmup 5 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
   "pyflakes crates/ruff_linter/resources/test/cpython" \
   "autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython" \
   "pycodestyle crates/ruff_linter/resources/test/cpython" \
@@ -464,7 +472,7 @@ To benchmark a subset of rules, e.g. `LineTooLong` and `DocLineTooLong`:
 
 ```shell
 cargo build --release && hyperfine --warmup 10 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
 ```
 
 You can run `poetry install` from `./scripts/benchmarks` to create a working environment for the
@@ -521,8 +529,6 @@ You can run the benchmarks with
 cargo benchmark
 ```
 
-`cargo benchmark` is an alias for `cargo bench -p ruff_benchmark --bench linter --bench formatter --`
-
 #### Benchmark-driven Development
 
 Ruff uses [Criterion.rs](https://bheisler.github.io/criterion.rs/book/) for benchmarks. You can use
@@ -561,7 +567,7 @@ cargo install critcmp
 
 #### Tips
 
-- Use `cargo bench -p ruff_benchmark <filter>` to only run specific benchmarks. For example: `cargo bench -p ruff_benchmark lexer`
+- Use `cargo bench -p ruff_benchmark <filter>` to only run specific benchmarks. For example: `cargo benchmark lexer`
     to only run the lexer benchmarks.
 - Use `cargo bench -p ruff_benchmark -- --quiet` for a more cleaned up output (without statistical relevance)
 - Use `cargo bench -p ruff_benchmark -- --quick` to get faster results (more prone to noise)
@@ -631,11 +637,11 @@ Otherwise, follow the instructions from the linux section.
 `cargo dev` is a shortcut for `cargo run --package ruff_dev --bin ruff_dev`. You can run some useful
 utils with it:
 
-- `cargo dev print-ast <file>`: Print the AST of a python file using Ruff's
-    [Python parser](https://github.com/astral-sh/ruff/tree/main/crates/ruff_python_parser).
-    For `if True: pass # comment`, you can see the syntax tree, the byte offsets for start and
-    stop of each node and also how the `:` token, the comment and whitespace are not represented
-    anymore:
+- `cargo dev print-ast <file>`: Print the AST of a python file using the
+    [RustPython parser](https://github.com/astral-sh/ruff/tree/main/crates/ruff_python_parser) that is
+    mainly used in Ruff. For `if True: pass # comment`, you can see the syntax tree, the byte offsets
+    for start and stop of each node and also how the `:` token, the comment and whitespace are not
+    represented anymore:
 
 ```text
 [
@@ -898,11 +904,15 @@ There are three ways in which an import can be categorized as "first-party":
     package (e.g., `from foo import bar` or `import foo.bar`), they'll be classified as first-party
     automatically. This check is as simple as comparing the first segment of the current file's
     module path to the first segment of the import.
-1. **Source roots**: Ruff supports a [`src`](https://docs.astral.sh/ruff/settings/#src) setting, which
+1. **Source roots**: Ruff supports a `[src](https://docs.astral.sh/ruff/settings/#src)` setting, which
     sets the directories to scan when identifying first-party imports. The algorithm is
     straightforward: given an import, like `import foo`, iterate over the directories enumerated in
     the `src` setting and, for each directory, check for the existence of a subdirectory `foo` or a
     file `foo.py`.
 
-By default, `src` is set to the project root, along with `"src"` subdirectory in the project root.
-This ensures that Ruff supports both flat and "src" layouts out of the box.
+By default, `src` is set to the project root. In the above example, we'd want to set
+`src = ["./src"]` to ensure that we locate `./my_project/src/foo` and thus categorize `import foo`
+as first-party in `baz.py`. In practice, for this limited example, setting `src = ["./src"]` is
+unnecessary, as all imports within `./my_project/src/foo` would be categorized as first-party via
+the same-package heuristic; but if your project contains multiple packages, you'll want to set `src`
+explicitly.

Cargo.toml

@@ -4,7 +4,7 @@ resolver = "2"
 
 [workspace.package]
 edition = "2021"
-rust-version = "1.80"
+rust-version = "1.71"
 homepage = "https://docs.astral.sh/ruff"
 documentation = "https://docs.astral.sh/ruff"
 repository = "https://github.com/astral-sh/ruff"
@@ -12,123 +12,86 @@ authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
 license = "MIT"
 
 [workspace.dependencies]
-ruff = { path = "crates/ruff" }
-ruff_cache = { path = "crates/ruff_cache" }
-ruff_db = { path = "crates/ruff_db", default-features = false }
-ruff_diagnostics = { path = "crates/ruff_diagnostics" }
-ruff_formatter = { path = "crates/ruff_formatter" }
-ruff_graph = { path = "crates/ruff_graph" }
-ruff_index = { path = "crates/ruff_index" }
-ruff_linter = { path = "crates/ruff_linter" }
-ruff_macros = { path = "crates/ruff_macros" }
-ruff_notebook = { path = "crates/ruff_notebook" }
-ruff_python_ast = { path = "crates/ruff_python_ast" }
-ruff_python_codegen = { path = "crates/ruff_python_codegen" }
-ruff_python_formatter = { path = "crates/ruff_python_formatter" }
-ruff_python_index = { path = "crates/ruff_python_index" }
-ruff_python_literal = { path = "crates/ruff_python_literal" }
-ruff_python_parser = { path = "crates/ruff_python_parser" }
-ruff_python_semantic = { path = "crates/ruff_python_semantic" }
-ruff_python_stdlib = { path = "crates/ruff_python_stdlib" }
-ruff_python_trivia = { path = "crates/ruff_python_trivia" }
-ruff_server = { path = "crates/ruff_server" }
-ruff_source_file = { path = "crates/ruff_source_file" }
-ruff_text_size = { path = "crates/ruff_text_size" }
-red_knot_vendored = { path = "crates/red_knot_vendored" }
-ruff_workspace = { path = "crates/ruff_workspace" }
-
-red_knot_python_semantic = { path = "crates/red_knot_python_semantic" }
-red_knot_server = { path = "crates/red_knot_server" }
-red_knot_test = { path = "crates/red_knot_test" }
-red_knot_workspace = { path = "crates/red_knot_workspace", default-features = false }
-
 aho-corasick = { version = "1.1.3" }
 annotate-snippets = { version = "0.9.2", features = ["color"] }
 anyhow = { version = "1.0.80" }
-assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
 bincode = { version = "1.3.3" }
 bitflags = { version = "2.5.0" }
 bstr = { version = "1.9.1" }
 cachedir = { version = "0.3.1" }
-camino = { version = "1.1.7" }
 chrono = { version = "0.4.35", default-features = false, features = ["clock"] }
 clap = { version = "4.5.3", features = ["derive"] }
-clap_complete_command = { version = "0.6.0" }
+clap_complete_command = { version = "0.5.1" }
 clearscreen = { version = "3.0.0" }
 codspeed-criterion-compat = { version = "2.6.0", default-features = false }
 colored = { version = "2.1.0" }
 console_error_panic_hook = { version = "0.1.7" }
 console_log = { version = "1.0.0" }
 countme = { version = "3.0.1" }
-compact_str = "0.8.0"
 criterion = { version = "0.5.1", default-features = false }
-crossbeam = { version = "0.8.4" }
-dashmap = { version = "6.0.1" }
-dir-test = { version = "0.4.0" }
-dunce = { version = "1.0.5" }
+crossbeam-channel = { version = "0.5.12" }
+dashmap = { version = "5.5.3" }
+dirs = { version = "5.0.0" }
 drop_bomb = { version = "0.1.5" }
 env_logger = { version = "0.11.0" }
-etcetera = { version = "0.8.0" }
-fern = { version = "0.7.0" }
+fern = { version = "0.6.1" }
 filetime = { version = "0.2.23" }
+fs-err = { version = "2.11.0" }
 glob = { version = "0.3.1" }
 globset = { version = "0.4.14" }
-globwalk = { version = "0.9.1" }
-hashbrown = { version = "0.15.0", default-features = false, features = [
-    "raw-entry",
-    "inline-more",
-] }
+hashbrown = "0.14.3"
+hexf-parse = { version = "0.2.1" }
 ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
 imperative = { version = "1.0.4" }
-indexmap = { version = "2.6.0" }
+indexmap = { version = "2.2.6" }
 indicatif = { version = "0.17.8" }
 indoc = { version = "2.0.4" }
-insta = { version = "1.35.1" }
+insta = { version = "1.35.1", feature = ["filters", "glob"] }
 insta-cmd = { version = "0.6.0" }
 is-macro = { version = "0.3.5" }
 is-wsl = { version = "0.4.0" }
-itertools = { version = "0.13.0" }
+itertools = { version = "0.12.1" }
 js-sys = { version = "0.3.69" }
 jod-thread = { version = "0.1.2" }
+lexical-parse-float = { version = "0.8.0", features = ["format"] }
 libc = { version = "0.2.153" }
 libcst = { version = "1.1.0", default-features = false }
 log = { version = "0.4.17" }
 lsp-server = { version = "0.7.6" }
-lsp-types = { git = "https://github.com/astral-sh/lsp-types.git", rev = "3512a9f", features = [
-    "proposed",
-] }
+lsp-types = { version = "0.95.0", features = ["proposed"] }
 matchit = { version = "0.8.1" }
 memchr = { version = "2.7.1" }
 mimalloc = { version = "0.1.39" }
 natord = { version = "1.0.9" }
-notify = { version = "7.0.0" }
-ordermap = { version = "0.5.0" }
+notify = { version = "6.1.1" }
+num_cpus = { version = "1.16.0" }
+once_cell = { version = "1.19.0" }
 path-absolutize = { version = "3.1.1" }
 path-slash = { version = "0.2.1" }
 pathdiff = { version = "0.2.1" }
-pep440_rs = { version = "0.7.1" }
+parking_lot = "0.12.1"
+pep440_rs = { version = "0.6.0", features = ["serde"] }
 pretty_assertions = "1.3.0"
 proc-macro2 = { version = "1.0.79" }
-pyproject-toml = { version = "0.13.4" }
-quick-junit = { version = "0.5.0" }
+pyproject-toml = { version = "0.9.0" }
+quick-junit = { version = "0.4.0" }
 quote = { version = "1.0.23" }
 rand = { version = "0.8.5" }
 rayon = { version = "1.10.0" }
 regex = { version = "1.10.2" }
-rustc-hash = { version = "2.0.0" }
-salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "254c749b02cde2fd29852a7463a33e800b771758" }
+result-like = { version = "0.5.0" }
+rustc-hash = { version = "1.1.0" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
 serde-wasm-bindgen = { version = "0.6.4" }
 serde_json = { version = "1.0.113" }
 serde_test = { version = "1.0.152" }
-serde_with = { version = "3.6.0", default-features = false, features = [
-    "macros",
-] }
+serde_with = { version = "3.6.0", default-features = false, features = ["macros"] }
 shellexpand = { version = "3.0.0" }
+shlex = { version = "1.3.0" }
 similar = { version = "2.4.0", features = ["inline"] }
 smallvec = { version = "1.13.2" }
 static_assertions = "1.1.0"
@@ -137,44 +100,30 @@ strum_macros = { version = "0.26.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
-thiserror = { version = "2.0.0" }
-tikv-jemallocator = { version = "0.6.0" }
+thiserror = { version = "1.0.58" }
+tikv-jemallocator = { version = "0.5.0" }
 toml = { version = "0.8.11" }
 tracing = { version = "0.1.40" }
-tracing-flame = { version = "0.2.0" }
 tracing-indicatif = { version = "0.3.6" }
-tracing-subscriber = { version = "0.3.18", default-features = false, features = [
-    "env-filter",
-    "fmt",
-] }
-tracing-tree = { version = "0.4.0" }
+tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+tracing-tree = { version = "0.3.0" }
 typed-arena = { version = "2.0.2" }
 unic-ucd-category = { version = "0.9" }
 unicode-ident = { version = "1.0.12" }
-unicode-width = { version = "0.2.0" }
+unicode-width = { version = "0.1.11" }
 unicode_names2 = { version = "1.2.2" }
 unicode-normalization = { version = "0.1.23" }
 ureq = { version = "2.9.6" }
 url = { version = "2.5.0" }
-uuid = { version = "1.6.1", features = [
-    "v4",
-    "fast-rng",
-    "macro-diagnostics",
-    "js",
-] }
+uuid = { version = "1.6.1", features = ["v4", "fast-rng", "macro-diagnostics", "js"] }
 walkdir = { version = "2.3.2" }
 wasm-bindgen = { version = "0.2.92" }
 wasm-bindgen-test = { version = "0.3.42" }
 wild = { version = "2" }
-zip = { version = "0.6.6", default-features = false }
 
 [workspace.lints.rust]
 unsafe_code = "warn"
 unreachable_pub = "warn"
-unexpected_cfgs = { level = "warn", check-cfg = [
-    "cfg(fuzzing)",
-    "cfg(codspeed)",
-] }
 
 [workspace.lints.clippy]
 pedantic = { level = "warn", priority = -2 }
@@ -183,16 +132,14 @@ char_lit_as_u8 = "allow"
 collapsible_else_if = "allow"
 collapsible_if = "allow"
 implicit_hasher = "allow"
-map_unwrap_or = "allow"
 match_same_arms = "allow"
 missing_errors_doc = "allow"
 missing_panics_doc = "allow"
 module_name_repetitions = "allow"
 must_use_candidate = "allow"
 similar_names = "allow"
-single_match_else = "allow"
 too_many_lines = "allow"
-# Without the hashes we run into a `rustfmt` bug in some snapshot tests, see #13250
+# To allow `#[allow(clippy::all)]` in `crates/ruff_python_parser/src/python.rs`.
 needless_raw_string_hashes = "allow"
 # Disallowed restriction lints
 print_stdout = "warn"
@@ -205,10 +152,6 @@ get_unwrap = "warn"
 rc_buffer = "warn"
 rc_mutex = "warn"
 rest_pat_in_fully_bound_structs = "warn"
-# nursery rules
-redundant_clone = "warn"
-debug_assert_with_mut_call = "warn"
-unused_peekable = "warn"
 
 [profile.release]
 # Note that we set these explicitly, and these values
@@ -243,64 +186,3 @@ opt-level = 1
 [profile.profiling]
 inherits = "release"
 debug = 1
-
-# The profile that 'cargo dist' will build with.
-[profile.dist]
-inherits = "release"
-
-# Config for 'dist'
-[workspace.metadata.dist]
-# The preferred dist version to use in CI (Cargo.toml SemVer syntax)
-cargo-dist-version = "0.25.2-prerelease.3"
-# CI backends to support
-ci = "github"
-# The installers to generate for each app
-installers = ["shell", "powershell"]
-# The archive format to use for windows builds (defaults .zip)
-windows-archive = ".zip"
-# The archive format to use for non-windows builds (defaults .tar.xz)
-unix-archive = ".tar.gz"
-# Target platforms to build apps for (Rust target-triple syntax)
-targets = [
-    "aarch64-apple-darwin",
-    "aarch64-pc-windows-msvc",
-    "aarch64-unknown-linux-gnu",
-    "aarch64-unknown-linux-musl",
-    "arm-unknown-linux-musleabihf",
-    "armv7-unknown-linux-gnueabihf",
-    "armv7-unknown-linux-musleabihf",
-    "i686-pc-windows-msvc",
-    "i686-unknown-linux-gnu",
-    "i686-unknown-linux-musl",
-    "powerpc64-unknown-linux-gnu",
-    "powerpc64le-unknown-linux-gnu",
-    "s390x-unknown-linux-gnu",
-    "x86_64-apple-darwin",
-    "x86_64-pc-windows-msvc",
-    "x86_64-unknown-linux-gnu",
-    "x86_64-unknown-linux-musl",
-]
-# Whether to auto-include files like READMEs, LICENSEs, and CHANGELOGs (default true)
-auto-includes = false
-# Whether dist should create a Github Release or use an existing draft
-create-release = true
-# Which actions to run on pull requests
-pr-run-mode = "skip"
-# Whether CI should trigger releases with dispatches instead of tag pushes
-dispatch-releases = true
-# Which phase dist should use to create the GitHub release
-github-release = "announce"
-# Whether CI should include auto-generated code to build local artifacts
-build-local-artifacts = false
-# Local artifacts jobs to run in CI
-local-artifacts-jobs = ["./build-binaries", "./build-docker"]
-# Publish jobs to run in CI
-publish-jobs = ["./publish-pypi", "./publish-wasm"]
-# Post-announce jobs to run in CI
-post-announce-jobs = ["./notify-dependents", "./publish-docs", "./publish-playground"]
-# Custom permissions for GitHub Jobs
-github-custom-job-permissions = { "build-docker" = { packages = "write", contents = "read" }, "publish-wasm" = { contents = "read", id-token = "write", packages = "write" } }
-# Whether to install an updater program
-install-updater = false
-# Path that installers should place binaries in
-install-path = ["$XDG_BIN_HOME/", "$XDG_DATA_HOME/../bin", "~/.local/bin"]

Dockerfile

@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM ubuntu AS build
+FROM --platform=$BUILDPLATFORM ubuntu as build
 ENV HOME="/root"
 WORKDIR $HOME
 

LICENSE

@@ -1371,28 +1371,3 @@ are:
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.
   """
-
-- pydoclint, licensed as follows:
-  """
-    MIT License
-
-    Copyright (c) 2023 jsh9
-
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included in all
-    copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-    SOFTWARE.
-  """

README.md

@@ -28,15 +28,15 @@ An extremely fast Python linter and code formatter, written in Rust.
 - ⚡️ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
 - 🐍 Installable via `pip`
 - 🛠️ `pyproject.toml` support
-- 🤝 Python 3.13 compatibility
-- ⚖️ Drop-in parity with [Flake8](https://docs.astral.sh/ruff/faq/#how-does-ruffs-linter-compare-to-flake8), isort, and [Black](https://docs.astral.sh/ruff/faq/#how-does-ruffs-formatter-compare-to-black)
+- 🤝 Python 3.12 compatibility
+- ⚖️ Drop-in parity with [Flake8](https://docs.astral.sh/ruff/faq/#how-does-ruff-compare-to-flake8), isort, and Black
 - 📦 Built-in caching, to avoid re-analyzing unchanged files
 - 🔧 Fix support, for automatic error correction (e.g., automatically remove unused imports)
 - 📏 Over [800 built-in rules](https://docs.astral.sh/ruff/rules/), with native re-implementations
     of popular Flake8 plugins, like flake8-bugbear
 - ⌨️ First-party [editor integrations](https://docs.astral.sh/ruff/integrations/) for
-    [VS Code](https://github.com/astral-sh/ruff-vscode) and [more](https://docs.astral.sh/ruff/editors/setup)
-- 🌎 Monorepo-friendly, with [hierarchical and cascading configuration](https://docs.astral.sh/ruff/configuration/#config-file-discovery)
+    [VS Code](https://github.com/astral-sh/ruff-vscode) and [more](https://github.com/astral-sh/ruff-lsp)
+- 🌎 Monorepo-friendly, with [hierarchical and cascading configuration](https://docs.astral.sh/ruff/configuration/#pyprojecttoml-discovery)
 
 Ruff aims to be orders of magnitude faster than alternative tools while integrating more
 functionality behind a single, common interface.
@@ -110,7 +110,7 @@ For more, see the [documentation](https://docs.astral.sh/ruff/).
 1. [Who's Using Ruff?](#whos-using-ruff)
 1. [License](#license)
 
-## Getting Started<a id="getting-started"></a>
+## Getting Started
 
 For more, see the [documentation](https://docs.astral.sh/ruff/).
 
@@ -119,25 +119,7 @@ For more, see the [documentation](https://docs.astral.sh/ruff/).
 Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:
 
 ```shell
-# With pip.
 pip install ruff
-
-# With pipx.
-pipx install ruff
-```
-
-Starting with version `0.5.0`, Ruff can be installed with our standalone installers:
-
-```shell
-# On macOS and Linux.
-curl -LsSf https://astral.sh/ruff/install.sh | sh
-
-# On Windows.
-powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
-
-# For a specific version.
-curl -LsSf https://astral.sh/ruff/0.8.0/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.8.0/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -170,7 +152,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.8.0
+  rev: v0.4.2
   hooks:
     # Run the linter.
     - id: ruff
@@ -179,10 +161,11 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
     - id: ruff-format
 ```
 
-Ruff can also be used as a [VS Code extension](https://github.com/astral-sh/ruff-vscode) or with [various other editors](https://docs.astral.sh/ruff/editors/setup).
+Ruff can also be used as a [VS Code extension](https://github.com/astral-sh/ruff-vscode) or
+alongside any other editor through the [Ruff LSP](https://github.com/astral-sh/ruff-lsp).
 
 Ruff can also be used as a [GitHub Action](https://github.com/features/actions) via
-[`ruff-action`](https://github.com/astral-sh/ruff-action):
+[`ruff-action`](https://github.com/chartboost/ruff-action):
 
 ```yaml
 name: Ruff
@@ -192,10 +175,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: astral-sh/ruff-action@v1
+      - uses: chartboost/ruff-action@v1
 ```
 
-### Configuration<a id="configuration"></a>
+### Configuration
 
 Ruff can be configured through a `pyproject.toml`, `ruff.toml`, or `.ruff.toml` file (see:
 [_Configuration_](https://docs.astral.sh/ruff/configuration/), or [_Settings_](https://docs.astral.sh/ruff/settings/)
@@ -238,8 +221,8 @@ exclude = [
 line-length = 88
 indent-width = 4
 
-# Assume Python 3.9
-target-version = "py39"
+# Assume Python 3.8
+target-version = "py38"
 
 [lint]
 # Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
@@ -283,15 +266,10 @@ The remaining configuration options can be provided through a catch-all `--confi
 ruff check --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"
 ```
 
-To opt in to the latest lint rules, formatter style changes, interface updates, and more, enable
-[preview mode](https://docs.astral.sh/ruff/rules/) by setting `preview = true` in your configuration
-file or passing `--preview` on the command line. Preview mode enables a collection of unstable
-features that may change prior to stabilization.
-
 See `ruff help` for more on Ruff's top-level commands, or `ruff help check` and `ruff help format`
 for more on the linting and formatting commands, respectively.
 
-## Rules<a id="rules"></a>
+## Rules
 
 <!-- Begin section: Rules -->
 
@@ -351,6 +329,7 @@ quality tools, including:
 - [flake8-super](https://pypi.org/project/flake8-super/)
 - [flake8-tidy-imports](https://pypi.org/project/flake8-tidy-imports/)
 - [flake8-todos](https://pypi.org/project/flake8-todos/)
+- [flake8-trio](https://pypi.org/project/flake8-trio/)
 - [flake8-type-checking](https://pypi.org/project/flake8-type-checking/)
 - [flake8-use-pathlib](https://pypi.org/project/flake8-use-pathlib/)
 - [flynt](https://pypi.org/project/flynt/) ([#2102](https://github.com/astral-sh/ruff/issues/2102))
@@ -367,21 +346,21 @@ quality tools, including:
 
 For a complete enumeration of the supported rules, see [_Rules_](https://docs.astral.sh/ruff/rules/).
 
-## Contributing<a id="contributing"></a>
+## Contributing
 
 Contributions are welcome and highly appreciated. To get started, check out the
 [**contributing guidelines**](https://docs.astral.sh/ruff/contributing/).
 
 You can also join us on [**Discord**](https://discord.com/invite/astral-sh).
 
-## Support<a id="support"></a>
+## Support
 
 Having trouble? Check out the existing issues on [**GitHub**](https://github.com/astral-sh/ruff/issues),
 or feel free to [**open a new one**](https://github.com/astral-sh/ruff/issues/new).
 
 You can also ask for help on [**Discord**](https://discord.com/invite/astral-sh).
 
-## Acknowledgements<a id="acknowledgements"></a>
+## Acknowledgements
 
 Ruff's linter draws on both the APIs and implementation details of many other
 tools in the Python ecosystem, especially [Flake8](https://github.com/PyCQA/flake8), [Pyflakes](https://github.com/PyCQA/pyflakes),
@@ -405,7 +384,7 @@ Ruff is the beneficiary of a large number of [contributors](https://github.com/a
 
 Ruff is released under the MIT license.
 
-## Who's Using Ruff?<a id="whos-using-ruff"></a>
+## Who's Using Ruff?
 
 Ruff is used by a number of major open-source projects and companies, including:
 
@@ -417,16 +396,13 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Babel](https://github.com/python-babel/babel)
 - Benchling ([Refac](https://github.com/benchling/refac))
 - [Bokeh](https://github.com/bokeh/bokeh)
-- CrowdCent ([NumerBlox](https://github.com/crowdcent/numerblox)) <!-- typos: ignore -->
 - [Cryptography (PyCA)](https://github.com/pyca/cryptography)
 - CERN ([Indico](https://getindico.io/))
 - [DVC](https://github.com/iterative/dvc)
 - [Dagger](https://github.com/dagger/dagger)
 - [Dagster](https://github.com/dagster-io/dagster)
 - Databricks ([MLflow](https://github.com/mlflow/mlflow))
-- [Dify](https://github.com/langgenius/dify)
 - [FastAPI](https://github.com/tiangolo/fastapi)
-- [Godot](https://github.com/godotengine/godot)
 - [Gradio](https://github.com/gradio-app/gradio)
 - [Great Expectations](https://github.com/great-expectations/great_expectations)
 - [HTTPX](https://github.com/encode/httpx)
@@ -435,7 +411,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - Hugging Face ([Transformers](https://github.com/huggingface/transformers),
     [Datasets](https://github.com/huggingface/datasets),
     [Diffusers](https://github.com/huggingface/diffusers))
-- IBM ([Qiskit](https://github.com/Qiskit/qiskit))
 - ING Bank ([popmon](https://github.com/ing-bank/popmon), [probatus](https://github.com/ing-bank/probatus))
 - [Ibis](https://github.com/ibis-project/ibis)
 - [ivy](https://github.com/unifyai/ivy)
@@ -450,10 +425,9 @@ Ruff is used by a number of major open-source projects and companies, including:
 - Microsoft ([Semantic Kernel](https://github.com/microsoft/semantic-kernel),
     [ONNX Runtime](https://github.com/microsoft/onnxruntime),
     [LightGBM](https://github.com/microsoft/LightGBM))
-- Modern Treasury ([Python SDK](https://github.com/Modern-Treasury/modern-treasury-python))
+- Modern Treasury ([Python SDK](https://github.com/Modern-Treasury/modern-treasury-python-sdk))
 - Mozilla ([Firefox](https://github.com/mozilla/gecko-dev))
 - [Mypy](https://github.com/python/mypy)
-- [Nautobot](https://github.com/nautobot/nautobot)
 - Netflix ([Dispatch](https://github.com/Netflix/dispatch))
 - [Neon](https://github.com/neondatabase/neon)
 - [Nokia](https://nokia.com/)
@@ -461,7 +435,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [NumPyro](https://github.com/pyro-ppl/numpyro)
 - [ONNX](https://github.com/onnx/onnx)
 - [OpenBB](https://github.com/OpenBB-finance/OpenBBTerminal)
-- [Open Wine Components](https://github.com/Open-Wine-Components/umu-launcher)
 - [PDM](https://github.com/pdm-project/pdm)
 - [PaddlePaddle](https://github.com/PaddlePaddle/Paddle)
 - [Pandas](https://github.com/pandas-dev/pandas)
@@ -489,7 +462,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Sphinx](https://github.com/sphinx-doc/sphinx)
 - [Stable Baselines3](https://github.com/DLR-RM/stable-baselines3)
 - [Starlette](https://github.com/encode/starlette)
-- [Streamlit](https://github.com/streamlit/streamlit)
 - [The Algorithms](https://github.com/TheAlgorithms/Python)
 - [Vega-Altair](https://github.com/altair-viz/altair)
 - WordPress ([Openverse](https://github.com/WordPress/openverse))
@@ -525,7 +497,7 @@ If you're using Ruff, consider adding the Ruff badge to your project's `README.m
 <a href="https://github.com/astral-sh/ruff"><img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json" alt="Ruff" style="max-width:100%;"></a>
 ```
 
-## License<a id="license"></a>
+## License
 
 This repository is licensed under the [MIT License](https://github.com/astral-sh/ruff/blob/main/LICENSE)
 

_typos.toml

@@ -1,11 +1,6 @@
 [files]
 # https://github.com/crate-ci/typos/issues/868
-extend-exclude = [
-  "crates/red_knot_vendored/vendor/**/*",
-  "**/resources/**/*",
-  "**/snapshots/**/*",
-  "crates/red_knot_workspace/src/workspace/pyproject/package_name.rs"
-]
+extend-exclude = ["**/resources/**/*", "**/snapshots/**/*"]
 
 [default.extend-words]
 "arange" = "arange"  # e.g. `numpy.arange`
@@ -13,15 +8,12 @@ hel = "hel"
 whos = "whos"
 spawnve = "spawnve"
 ned = "ned"
-pn = "pn"  # `import panel as pn` is a thing
+pn = "pn"  # `import panel as pd` is a thing
 poit = "poit"
 BA = "BA" # acronym for "Bad Allowed", used in testing.
-jod = "jod" # e.g., `jod-thread`
-Numer = "Numer" # Library name 'NumerBlox' in "Who's Using Ruff?"
 
 [default]
 extend-ignore-re = [
   # Line ignore with trailing "spellchecker:disable-line"
-  "(?Rm)^.*#\\s*spellchecker:disable-line$",
-  "LICENSEs",
+  "(?Rm)^.*#\\s*spellchecker:disable-line$"
 ]

clippy.toml

@@ -1,21 +1,7 @@
 doc-valid-idents = [
-  "..",
-  "CodeQL",
-  "FastAPI",
-  "IPython",
-  "LangChain",
-  "LibCST",
-  "McCabe",
-  "NumPy",
-  "SCREAMING_SNAKE_CASE",
-  "SQLAlchemy",
   "StackOverflow",
-  "PyCharm",
-]
-
-ignore-interior-mutability = [
-  # Interned is read-only. The wrapped `Rc` never gets updated.
-  "ruff_formatter::format_element::Interned",
-  # The expression is read-only.
-  "ruff_python_ast::hashable::HashableExpr",
+  "CodeQL",
+  "IPython",
+  "NumPy",
+  "..",
 ]

crates/red_knot/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "red_knot"
-version = "0.0.0"
+version = "0.1.0"
 edition.workspace = true
 rust-version.workspace = true
 homepage.workspace = true
@@ -12,29 +12,34 @@ license.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-red_knot_python_semantic = { workspace = true }
-red_knot_workspace = { workspace = true, features = ["zstd"] }
-red_knot_server = { workspace = true }
-ruff_db = { workspace = true, features = ["os", "cache"] }
+ruff_python_parser = { path = "../ruff_python_parser" }
+ruff_python_ast = { path = "../ruff_python_ast" }
+ruff_python_trivia = { path = "../ruff_python_trivia" }
+ruff_text_size = { path = "../ruff_text_size" }
+ruff_index = { path = "../ruff_index" }
+ruff_notebook = { path = "../ruff_notebook" }
 
 anyhow = { workspace = true }
-chrono = { workspace = true }
-clap = { workspace = true, features = ["wrap_help"] }
-colored = { workspace = true }
-countme = { workspace = true, features = ["enable"] }
-crossbeam = { workspace = true }
-ctrlc = { version = "3.4.4" }
+bitflags = { workspace = true }
+ctrlc = "3.4.4"
+crossbeam-channel = { workspace = true }
+dashmap = { workspace = true }
+hashbrown = { workspace = true }
+indexmap = { workspace = true }
+log = { workspace = true }
+notify = { workspace = true }
+parking_lot = { workspace = true }
 rayon = { workspace = true }
-salsa = { workspace = true }
-tracing = { workspace = true, features = ["release_max_level_debug"] }
-tracing-subscriber = { workspace = true, features = ["env-filter", "fmt"] }
-tracing-flame = { workspace = true }
+rustc-hash = { workspace = true }
+smallvec = { workspace = true }
+smol_str = "0.2.1"
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }
 tracing-tree = { workspace = true }
 
 [dev-dependencies]
-filetime = { workspace = true }
+textwrap = "0.16.1"
 tempfile = { workspace = true }
-ruff_db = { workspace = true, features = ["testing"] }
 
 [lints]
 workspace = true

crates/red_knot/docs/tracing.md

@@ -1,128 +0,0 @@
-# Tracing
-
-Traces are a useful tool to narrow down the location of a bug or, at least, to understand why the compiler is doing a particular thing.
-Note, tracing messages with severity `debug` or greater are user-facing. They should be phrased accordingly.
-Tracing spans are only shown when using `-vvv`.
-
-## Verbosity levels
-
-The CLI supports different verbosity levels.
-
-- default: Only show errors and warnings.
-- `-v` activates `info!`: Show generally useful information such as paths of configuration files, detected platform, etc., but it's not a lot of messages, it's something you'll activate in CI by default. cargo build e.g. shows you which packages are fresh.
-- `-vv` activates `debug!` and timestamps: This should be enough information to get to the bottom of bug reports. When you're processing many packages or files, you'll get pages and pages of output, but each line is link to a specific action or state change.
-- `-vvv` activates `trace!` (only in debug builds) and shows tracing-spans: At this level, you're logging everything. Most of this is wasted, it's really slow, we dump e.g. the entire resolution graph. Only useful to developers, and you almost certainly want to use `RED_KNOT_LOG` to filter it down to the area your investigating.
-
-## Better logging with `RED_KNOT_LOG` and `RAYON_NUM_THREADS`
-
-By default, the CLI shows messages from the `ruff` and `red_knot` crates. Tracing messages from other crates are not shown.
-The `RED_KNOT_LOG` environment variable allows you to customize which messages are shown by specifying one
-or more [filter directives](https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#directives).
-
-The `RAYON_NUM_THREADS` environment variable, meanwhile, can be used to control the level of concurrency red-knot uses.
-By default, red-knot will attempt to parallelize its work so that multiple files are checked simultaneously,
-but this can result in a confused logging output where messages from different threads are intertwined.
-To switch off concurrency entirely and have more readable logs, use `RAYON_NUM_THREADS=1`.
-
-### Examples
-
-#### Show all debug messages
-
-Shows debug messages from all crates.
-
-```bash
-RED_KNOT_LOG=debug
-```
-
-#### Show salsa query execution messages
-
-Show the salsa `execute: my_query` messages in addition to all red knot messages.
-
-```bash
-RED_KNOT_LOG=ruff=trace,red_knot=trace,salsa=info
-```
-
-#### Show typing traces
-
-Only show traces for the `red_knot_python_semantic::types` module.
-
-```bash
-RED_KNOT_LOG="red_knot_python_semantic::types"
-```
-
-Note: Ensure that you use `-vvv` to see tracing spans.
-
-#### Show messages for a single file
-
-Shows all messages that are inside of a span for a specific file.
-
-```bash
-RED_KNOT_LOG=red_knot[{file=/home/micha/astral/test/x.py}]=trace
-```
-
-**Note**: Tracing still shows all spans because tracing can't know at the time of entering the span
-whether one if its children has the file `x.py`.
-
-**Note**: Salsa currently logs the entire memoized values. In our case, the source text and parsed AST.
-This very quickly leads to extremely long outputs.
-
-## Tracing and Salsa
-
-Be mindful about using `tracing` in Salsa queries, especially when using `warn` or `error` because it isn't guaranteed
-that the query will execute after restoring from a persistent cache. In which case the user won't see the message.
-
-For example, don't use `tracing` to show the user a message when generating a lint violation failed
-because the message would only be shown when linting the file the first time, but not on subsequent analysis
-runs or when restoring from a persistent cache. This can be confusing for users because they
-don't understand why a specific lint violation isn't raised. Instead, change your
-query to return the failure as part of the query's result or use a Salsa accumulator.
-
-## Tracing in tests
-
-You can use `ruff_db::testing::setup_logging` or `ruff_db::testing::setup_logging_with_filter` to set up logging in tests.
-
-```rust
-use ruff_db::testing::setup_logging;
-
-#[test]
-fn test() {
-  let _logging = setup_logging();
-
-  tracing::info!("This message will be printed to stderr");
-}
-```
-
-Note: Most test runners capture stderr and only show its output when a test fails.
-
-Note also that `setup_logging` only sets up logging for the current thread because [`set_global_default`](https://docs.rs/tracing/latest/tracing/subscriber/fn.set_global_default.html) can only be
-called **once**.
-
-## Release builds
-
-`trace!` events are removed in release builds.
-
-## Profiling
-
-Red Knot generates a folded stack trace  to the current directory named `tracing.folded` when setting the environment variable `RED_KNOT_LOG_PROFILE` to `1` or `true`.
-
-```bash
-RED_KNOT_LOG_PROFILE=1 red_knot -- --current-directory=../test -vvv
-```
-
-You can convert the textual representation into a visual one using `inferno`.
-
-```shell
-cargo install inferno
-```
-
-```shell
-# flamegraph
-cat tracing.folded | inferno-flamegraph > tracing-flamegraph.svg
-
-# flamechart
-cat tracing.folded | inferno-flamegraph --flamechart > tracing-flamechart.svg
-```
-
-![Example flamegraph](./tracing-flamegraph.png)
-
-See [`tracing-flame`](https://crates.io/crates/tracing-flame) for more details.

crates/red_knot/src/ast_ids.rs

@@ -0,0 +1,415 @@
+use std::any::type_name;
+use std::fmt::{Debug, Formatter};
+use std::hash::{Hash, Hasher};
+use std::marker::PhantomData;
+
+use rustc_hash::FxHashMap;
+
+use ruff_index::{Idx, IndexVec};
+use ruff_python_ast::visitor::preorder;
+use ruff_python_ast::visitor::preorder::{PreorderVisitor, TraversalSignal};
+use ruff_python_ast::{
+    AnyNodeRef, AstNode, ExceptHandler, ExceptHandlerExceptHandler, Expr, MatchCase, ModModule,
+    NodeKind, Parameter, Stmt, StmtAnnAssign, StmtAssign, StmtAugAssign, StmtClassDef,
+    StmtFunctionDef, StmtGlobal, StmtImport, StmtImportFrom, StmtNonlocal, StmtTypeAlias,
+    TypeParam, TypeParamParamSpec, TypeParamTypeVar, TypeParamTypeVarTuple, WithItem,
+};
+use ruff_text_size::{Ranged, TextRange};
+
+/// A type agnostic ID that uniquely identifies an AST node in a file.
+#[ruff_index::newtype_index]
+pub struct AstId;
+
+/// A typed ID that uniquely identifies an AST node in a file.
+///
+/// This is different from [`AstId`] in that it is a combination of ID and the type of the node the ID identifies.
+/// Typing the ID prevents mixing IDs of different node types and allows to restrict the API to only accept
+/// nodes for which an ID has been created (not all AST nodes get an ID).
+pub struct TypedAstId<N: HasAstId> {
+    erased: AstId,
+    _marker: PhantomData<fn() -> N>,
+}
+
+impl<N: HasAstId> TypedAstId<N> {
+    /// Upcasts this ID from a more specific node type to a more general node type.
+    pub fn upcast<M: HasAstId>(self) -> TypedAstId<M>
+    where
+        N: Into<M>,
+    {
+        TypedAstId {
+            erased: self.erased,
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl<N: HasAstId> Copy for TypedAstId<N> {}
+impl<N: HasAstId> Clone for TypedAstId<N> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<N: HasAstId> PartialEq for TypedAstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.erased == other.erased
+    }
+}
+
+impl<N: HasAstId> Eq for TypedAstId<N> {}
+impl<N: HasAstId> Hash for TypedAstId<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.erased.hash(state);
+    }
+}
+
+impl<N: HasAstId> Debug for TypedAstId<N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("TypedAstId")
+            .field(&self.erased)
+            .field(&type_name::<N>())
+            .finish()
+    }
+}
+
+pub struct AstIds {
+    ids: IndexVec<AstId, NodeKey>,
+    reverse: FxHashMap<NodeKey, AstId>,
+}
+
+impl AstIds {
+    // TODO rust analyzer doesn't allocate an ID for every node. It only allocates ids for
+    //  nodes with a corresponding HIR element, that is nodes that are definitions.
+    pub fn from_module(module: &ModModule) -> Self {
+        let mut visitor = AstIdsVisitor::default();
+
+        // TODO: visit_module?
+        // Make sure we visit the root
+        visitor.create_id(module);
+        visitor.visit_body(&module.body);
+
+        while let Some(deferred) = visitor.deferred.pop() {
+            match deferred {
+                DeferredNode::FunctionDefinition(def) => {
+                    def.visit_preorder(&mut visitor);
+                }
+                DeferredNode::ClassDefinition(def) => def.visit_preorder(&mut visitor),
+            }
+        }
+
+        AstIds {
+            ids: visitor.ids,
+            reverse: visitor.reverse,
+        }
+    }
+
+    /// Returns the ID to the root node.
+    pub fn root(&self) -> NodeKey {
+        self.ids[AstId::new(0)]
+    }
+
+    /// Returns the [`TypedAstId`] for a node.
+    pub fn ast_id<N: HasAstId>(&self, node: &N) -> TypedAstId<N> {
+        let key = node.syntax_node_key();
+        TypedAstId {
+            erased: self.reverse.get(&key).copied().unwrap(),
+            _marker: PhantomData,
+        }
+    }
+
+    /// Returns the [`TypedAstId`] for the node identified with the given [`TypedNodeKey`].
+    pub fn ast_id_for_key<N: HasAstId>(&self, node: &TypedNodeKey<N>) -> TypedAstId<N> {
+        let ast_id = self.ast_id_for_node_key(node.inner);
+
+        TypedAstId {
+            erased: ast_id,
+            _marker: PhantomData,
+        }
+    }
+
+    /// Returns the untyped [`AstId`] for the node identified by the given `node` key.
+    pub fn ast_id_for_node_key(&self, node: NodeKey) -> AstId {
+        self.reverse
+            .get(&node)
+            .copied()
+            .expect("Can't find node in AstIds map.")
+    }
+
+    /// Returns the [`TypedNodeKey`] for the node identified by the given [`TypedAstId`].
+    pub fn key<N: HasAstId>(&self, id: TypedAstId<N>) -> TypedNodeKey<N> {
+        let syntax_key = self.ids[id.erased];
+
+        TypedNodeKey::new(syntax_key).unwrap()
+    }
+
+    pub fn node_key<H: HasAstId>(&self, id: TypedAstId<H>) -> NodeKey {
+        self.ids[id.erased]
+    }
+}
+
+impl std::fmt::Debug for AstIds {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut map = f.debug_map();
+        for (key, value) in self.ids.iter_enumerated() {
+            map.entry(&key, &value);
+        }
+
+        map.finish()
+    }
+}
+
+impl PartialEq for AstIds {
+    fn eq(&self, other: &Self) -> bool {
+        self.ids == other.ids
+    }
+}
+
+impl Eq for AstIds {}
+
+#[derive(Default)]
+struct AstIdsVisitor<'a> {
+    ids: IndexVec<AstId, NodeKey>,
+    reverse: FxHashMap<NodeKey, AstId>,
+    deferred: Vec<DeferredNode<'a>>,
+}
+
+impl<'a> AstIdsVisitor<'a> {
+    fn create_id<A: HasAstId>(&mut self, node: &A) {
+        let node_key = node.syntax_node_key();
+
+        let id = self.ids.push(node_key);
+        self.reverse.insert(node_key, id);
+    }
+}
+
+impl<'a> PreorderVisitor<'a> for AstIdsVisitor<'a> {
+    fn visit_stmt(&mut self, stmt: &'a Stmt) {
+        match stmt {
+            Stmt::FunctionDef(def) => {
+                self.create_id(def);
+                self.deferred.push(DeferredNode::FunctionDefinition(def));
+                return;
+            }
+            // TODO defer visiting the assignment body, type alias parameters etc?
+            Stmt::ClassDef(def) => {
+                self.create_id(def);
+                self.deferred.push(DeferredNode::ClassDefinition(def));
+                return;
+            }
+            Stmt::Expr(_) => {
+                // Skip
+                return;
+            }
+            Stmt::Return(_) => {}
+            Stmt::Delete(_) => {}
+            Stmt::Assign(assignment) => self.create_id(assignment),
+            Stmt::AugAssign(assignment) => {
+                self.create_id(assignment);
+            }
+            Stmt::AnnAssign(assignment) => self.create_id(assignment),
+            Stmt::TypeAlias(assignment) => self.create_id(assignment),
+            Stmt::For(_) => {}
+            Stmt::While(_) => {}
+            Stmt::If(_) => {}
+            Stmt::With(_) => {}
+            Stmt::Match(_) => {}
+            Stmt::Raise(_) => {}
+            Stmt::Try(_) => {}
+            Stmt::Assert(_) => {}
+            Stmt::Import(import) => self.create_id(import),
+            Stmt::ImportFrom(import_from) => self.create_id(import_from),
+            Stmt::Global(global) => self.create_id(global),
+            Stmt::Nonlocal(non_local) => self.create_id(non_local),
+            Stmt::Pass(_) => {}
+            Stmt::Break(_) => {}
+            Stmt::Continue(_) => {}
+            Stmt::IpyEscapeCommand(_) => {}
+        }
+
+        preorder::walk_stmt(self, stmt);
+    }
+
+    fn visit_expr(&mut self, _expr: &'a Expr) {}
+
+    fn visit_parameter(&mut self, parameter: &'a Parameter) {
+        self.create_id(parameter);
+        preorder::walk_parameter(self, parameter);
+    }
+
+    fn visit_except_handler(&mut self, except_handler: &'a ExceptHandler) {
+        match except_handler {
+            ExceptHandler::ExceptHandler(except_handler) => {
+                self.create_id(except_handler);
+            }
+        }
+
+        preorder::walk_except_handler(self, except_handler);
+    }
+
+    fn visit_with_item(&mut self, with_item: &'a WithItem) {
+        self.create_id(with_item);
+        preorder::walk_with_item(self, with_item);
+    }
+
+    fn visit_match_case(&mut self, match_case: &'a MatchCase) {
+        self.create_id(match_case);
+        preorder::walk_match_case(self, match_case);
+    }
+
+    fn visit_type_param(&mut self, type_param: &'a TypeParam) {
+        self.create_id(type_param);
+    }
+}
+
+enum DeferredNode<'a> {
+    FunctionDefinition(&'a StmtFunctionDef),
+    ClassDefinition(&'a StmtClassDef),
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct TypedNodeKey<N: AstNode> {
+    /// The type erased node key.
+    inner: NodeKey,
+    _marker: PhantomData<fn() -> N>,
+}
+
+impl<N: AstNode> TypedNodeKey<N> {
+    pub fn from_node(node: &N) -> Self {
+        let inner = NodeKey {
+            kind: node.as_any_node_ref().kind(),
+            range: node.range(),
+        };
+        Self {
+            inner,
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn new(node_key: NodeKey) -> Option<Self> {
+        N::can_cast(node_key.kind).then_some(TypedNodeKey {
+            inner: node_key,
+            _marker: PhantomData,
+        })
+    }
+
+    pub fn resolve<'a>(&self, root: AnyNodeRef<'a>) -> Option<N::Ref<'a>> {
+        let node_ref = self.inner.resolve(root)?;
+
+        Some(N::cast_ref(node_ref).unwrap())
+    }
+
+    pub fn resolve_unwrap<'a>(&self, root: AnyNodeRef<'a>) -> N::Ref<'a> {
+        self.resolve(root).expect("node should resolve")
+    }
+
+    pub fn erased(&self) -> &NodeKey {
+        &self.inner
+    }
+}
+
+struct FindNodeKeyVisitor<'a> {
+    key: NodeKey,
+    result: Option<AnyNodeRef<'a>>,
+}
+
+impl<'a> PreorderVisitor<'a> for FindNodeKeyVisitor<'a> {
+    fn enter_node(&mut self, node: AnyNodeRef<'a>) -> TraversalSignal {
+        if self.result.is_some() {
+            return TraversalSignal::Skip;
+        }
+
+        if node.range() == self.key.range && node.kind() == self.key.kind {
+            self.result = Some(node);
+            TraversalSignal::Skip
+        } else if node.range().contains_range(self.key.range) {
+            TraversalSignal::Traverse
+        } else {
+            TraversalSignal::Skip
+        }
+    }
+
+    fn visit_body(&mut self, body: &'a [Stmt]) {
+        // TODO it would be more efficient to use binary search instead of linear
+        for stmt in body {
+            if stmt.range().start() > self.key.range.end() {
+                break;
+            }
+
+            self.visit_stmt(stmt);
+        }
+    }
+}
+
+// TODO an alternative to this is to have a `NodeId` on each node (in increasing order depending on the position).
+//  This would allow to reduce the size of this to a u32.
+//  What would be nice if we could use an `Arc::weak_ref` here but that only works if we use
+//   `Arc` internally
+// TODO: Implement the logic to resolve a node, given a db (and the correct file).
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct NodeKey {
+    kind: NodeKind,
+    range: TextRange,
+}
+
+impl NodeKey {
+    pub fn resolve<'a>(&self, root: AnyNodeRef<'a>) -> Option<AnyNodeRef<'a>> {
+        // We need to do a binary search here. Only traverse into a node if the range is withint the node
+        let mut visitor = FindNodeKeyVisitor {
+            key: *self,
+            result: None,
+        };
+
+        if visitor.enter_node(root) == TraversalSignal::Traverse {
+            root.visit_preorder(&mut visitor);
+        }
+
+        visitor.result
+    }
+}
+
+/// Marker trait implemented by AST nodes for which we extract the `AstId`.
+pub trait HasAstId: AstNode {
+    fn node_key(&self) -> TypedNodeKey<Self>
+    where
+        Self: Sized,
+    {
+        TypedNodeKey {
+            inner: self.syntax_node_key(),
+            _marker: PhantomData,
+        }
+    }
+
+    fn syntax_node_key(&self) -> NodeKey {
+        NodeKey {
+            kind: self.as_any_node_ref().kind(),
+            range: self.range(),
+        }
+    }
+}
+
+impl HasAstId for StmtFunctionDef {}
+impl HasAstId for StmtClassDef {}
+impl HasAstId for StmtAnnAssign {}
+impl HasAstId for StmtAugAssign {}
+impl HasAstId for StmtAssign {}
+impl HasAstId for StmtTypeAlias {}
+
+impl HasAstId for ModModule {}
+
+impl HasAstId for StmtImport {}
+
+impl HasAstId for StmtImportFrom {}
+
+impl HasAstId for Parameter {}
+
+impl HasAstId for TypeParam {}
+impl HasAstId for Stmt {}
+impl HasAstId for TypeParamTypeVar {}
+impl HasAstId for TypeParamTypeVarTuple {}
+impl HasAstId for TypeParamParamSpec {}
+impl HasAstId for StmtGlobal {}
+impl HasAstId for StmtNonlocal {}
+
+impl HasAstId for ExceptHandlerExceptHandler {}
+impl HasAstId for WithItem {}
+impl HasAstId for MatchCase {}

crates/red_knot/src/cache.rs

@@ -0,0 +1,158 @@
+use std::fmt::Formatter;
+use std::hash::Hash;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use dashmap::mapref::entry::Entry;
+
+use crate::FxDashMap;
+
+/// Simple key value cache that locks on a per-key level.
+pub struct KeyValueCache<K, V> {
+    map: FxDashMap<K, V>,
+    statistics: CacheStatistics,
+}
+
+impl<K, V> KeyValueCache<K, V>
+where
+    K: Eq + Hash + Clone,
+    V: Clone,
+{
+    pub fn try_get(&self, key: &K) -> Option<V> {
+        if let Some(existing) = self.map.get(key) {
+            self.statistics.hit();
+            Some(existing.clone())
+        } else {
+            self.statistics.miss();
+            None
+        }
+    }
+
+    pub fn get<F>(&self, key: &K, compute: F) -> V
+    where
+        F: FnOnce(&K) -> V,
+    {
+        match self.map.entry(key.clone()) {
+            Entry::Occupied(cached) => {
+                self.statistics.hit();
+
+                cached.get().clone()
+            }
+            Entry::Vacant(vacant) => {
+                self.statistics.miss();
+
+                let value = compute(key);
+                vacant.insert(value.clone());
+                value
+            }
+        }
+    }
+
+    pub fn set(&mut self, key: K, value: V) {
+        self.map.insert(key, value);
+    }
+
+    pub fn remove(&mut self, key: &K) -> Option<V> {
+        self.map.remove(key).map(|(_, value)| value)
+    }
+
+    pub fn clear(&mut self) {
+        self.map.clear();
+        self.map.shrink_to_fit();
+    }
+
+    pub fn statistics(&self) -> Option<Statistics> {
+        self.statistics.to_statistics()
+    }
+}
+
+impl<K, V> Default for KeyValueCache<K, V>
+where
+    K: Eq + Hash,
+    V: Clone,
+{
+    fn default() -> Self {
+        Self {
+            map: FxDashMap::default(),
+            statistics: CacheStatistics::default(),
+        }
+    }
+}
+
+impl<K, V> std::fmt::Debug for KeyValueCache<K, V>
+where
+    K: std::fmt::Debug + Eq + Hash,
+    V: std::fmt::Debug,
+{
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut debug = f.debug_map();
+
+        for entry in &self.map {
+            debug.entry(&entry.value(), &entry.key());
+        }
+
+        debug.finish()
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Statistics {
+    pub hits: usize,
+    pub misses: usize,
+}
+
+impl Statistics {
+    #[allow(clippy::cast_precision_loss)]
+    pub fn hit_rate(&self) -> Option<f64> {
+        if self.hits + self.misses == 0 {
+            return None;
+        }
+
+        Some((self.hits as f64) / (self.hits + self.misses) as f64)
+    }
+}
+
+#[cfg(debug_assertions)]
+pub type CacheStatistics = DebugStatistics;
+
+#[cfg(not(debug_assertions))]
+pub type CacheStatistics = ReleaseStatistics;
+
+#[derive(Debug, Default)]
+pub struct DebugStatistics {
+    hits: AtomicUsize,
+    misses: AtomicUsize,
+}
+
+impl DebugStatistics {
+    // TODO figure out appropriate Ordering
+    pub fn hit(&self) {
+        self.hits.fetch_add(1, Ordering::SeqCst);
+    }
+
+    pub fn miss(&self) {
+        self.misses.fetch_add(1, Ordering::SeqCst);
+    }
+
+    pub fn to_statistics(&self) -> Option<Statistics> {
+        let hits = self.hits.load(Ordering::SeqCst);
+        let misses = self.misses.load(Ordering::SeqCst);
+
+        Some(Statistics { hits, misses })
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct ReleaseStatistics;
+
+impl ReleaseStatistics {
+    #[inline]
+    pub const fn hit(&self) {}
+
+    #[inline]
+    pub const fn miss(&self) {}
+
+    #[inline]
+    pub const fn to_statistics(&self) -> Option<Statistics> {
+        None
+    }
+}

crates/red_knot/src/cancellation.rs

@@ -0,0 +1,66 @@
+use std::sync::{Arc, Condvar, Mutex};
+
+#[derive(Debug, Default)]
+pub struct CancellationTokenSource {
+    signal: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl CancellationTokenSource {
+    pub fn new() -> Self {
+        Self {
+            signal: Arc::new((Mutex::new(false), Condvar::default())),
+        }
+    }
+
+    #[tracing::instrument(level = "trace")]
+    pub fn cancel(&self) {
+        let (cancelled, condvar) = &*self.signal;
+
+        let mut cancelled = cancelled.lock().unwrap();
+
+        if *cancelled {
+            return;
+        }
+
+        *cancelled = true;
+        condvar.notify_all();
+    }
+
+    pub fn is_cancelled(&self) -> bool {
+        let (cancelled, _) = &*self.signal;
+
+        *cancelled.lock().unwrap()
+    }
+
+    pub fn token(&self) -> CancellationToken {
+        CancellationToken {
+            signal: self.signal.clone(),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct CancellationToken {
+    signal: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl CancellationToken {
+    /// Returns `true` if cancellation has been requested.
+    pub fn is_cancelled(&self) -> bool {
+        let (cancelled, _) = &*self.signal;
+
+        *cancelled.lock().unwrap()
+    }
+
+    pub fn wait(&self) {
+        let (bool, condvar) = &*self.signal;
+
+        let lock = condvar
+            .wait_while(bool.lock().unwrap(), |bool| !*bool)
+            .unwrap();
+
+        debug_assert!(*lock);
+
+        drop(lock);
+    }
+}

crates/red_knot/src/db.rs

@@ -0,0 +1,178 @@
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::files::FileId;
+use crate::lint::{Diagnostics, LintSyntaxStorage};
+use crate::module::{Module, ModuleData, ModuleName, ModuleResolver, ModuleSearchPath};
+use crate::parse::{Parsed, ParsedStorage};
+use crate::source::{Source, SourceStorage};
+use crate::symbols::{SymbolId, SymbolTable, SymbolTablesStorage};
+use crate::types::{Type, TypeStore};
+
+pub trait SourceDb {
+    // queries
+    fn file_id(&self, path: &std::path::Path) -> FileId;
+
+    fn file_path(&self, file_id: FileId) -> Arc<std::path::Path>;
+
+    fn source(&self, file_id: FileId) -> Source;
+
+    fn parse(&self, file_id: FileId) -> Parsed;
+
+    fn lint_syntax(&self, file_id: FileId) -> Diagnostics;
+}
+
+pub trait SemanticDb: SourceDb {
+    // queries
+    fn resolve_module(&self, name: ModuleName) -> Option<Module>;
+
+    fn file_to_module(&self, file_id: FileId) -> Option<Module>;
+
+    fn path_to_module(&self, path: &Path) -> Option<Module>;
+
+    fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable>;
+
+    fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type;
+
+    // mutations
+
+    fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)>;
+
+    fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>);
+}
+
+pub trait Db: SemanticDb {}
+
+#[derive(Debug, Default)]
+pub struct SourceJar {
+    pub sources: SourceStorage,
+    pub parsed: ParsedStorage,
+    pub lint_syntax: LintSyntaxStorage,
+}
+
+#[derive(Debug, Default)]
+pub struct SemanticJar {
+    pub module_resolver: ModuleResolver,
+    pub symbol_tables: SymbolTablesStorage,
+    pub type_store: TypeStore,
+}
+
+/// Gives access to a specific jar in the database.
+///
+/// Nope, the terminology isn't borrowed from Java but from Salsa <https://salsa-rs.github.io/salsa/>,
+/// which is an analogy to storing the salsa in different jars.
+///
+/// The basic idea is that each crate can define its own jar and the jars can be combined to a single
+/// database in the top level crate. Each crate also defines its own `Database` trait. The combination of
+/// `Database` trait and the jar allows to write queries in isolation without having to know how they get composed at the upper levels.
+///
+/// Salsa further defines a `HasIngredient` trait which slices the jar to a specific storage (e.g. a specific cache).
+/// We don't need this just jet because we write our queries by hand. We may want a similar trait if we decide
+/// to use a macro to generate the queries.
+pub trait HasJar<T> {
+    /// Gives a read-only reference to the jar.
+    fn jar(&self) -> &T;
+
+    /// Gives a mutable reference to the jar.
+    fn jar_mut(&mut self) -> &mut T;
+}
+
+#[cfg(test)]
+pub(crate) mod tests {
+    use crate::db::{HasJar, SourceDb, SourceJar};
+    use crate::files::{FileId, Files};
+    use crate::lint::{lint_syntax, Diagnostics};
+    use crate::module::{
+        add_module, file_to_module, path_to_module, resolve_module, set_module_search_paths,
+        Module, ModuleData, ModuleName, ModuleSearchPath,
+    };
+    use crate::parse::{parse, Parsed};
+    use crate::source::{source_text, Source};
+    use crate::symbols::{symbol_table, SymbolId, SymbolTable};
+    use crate::types::{infer_symbol_type, Type};
+    use std::path::Path;
+    use std::sync::Arc;
+
+    use super::{SemanticDb, SemanticJar};
+
+    // This can be a partial database used in a single crate for testing.
+    // It would hold fewer data than the full database.
+    #[derive(Debug, Default)]
+    pub(crate) struct TestDb {
+        files: Files,
+        source: SourceJar,
+        semantic: SemanticJar,
+    }
+
+    impl HasJar<SourceJar> for TestDb {
+        fn jar(&self) -> &SourceJar {
+            &self.source
+        }
+
+        fn jar_mut(&mut self) -> &mut SourceJar {
+            &mut self.source
+        }
+    }
+
+    impl HasJar<SemanticJar> for TestDb {
+        fn jar(&self) -> &SemanticJar {
+            &self.semantic
+        }
+
+        fn jar_mut(&mut self) -> &mut SemanticJar {
+            &mut self.semantic
+        }
+    }
+
+    impl SourceDb for TestDb {
+        fn file_id(&self, path: &Path) -> FileId {
+            self.files.intern(path)
+        }
+
+        fn file_path(&self, file_id: FileId) -> Arc<Path> {
+            self.files.path(file_id)
+        }
+
+        fn source(&self, file_id: FileId) -> Source {
+            source_text(self, file_id)
+        }
+
+        fn parse(&self, file_id: FileId) -> Parsed {
+            parse(self, file_id)
+        }
+
+        fn lint_syntax(&self, file_id: FileId) -> Diagnostics {
+            lint_syntax(self, file_id)
+        }
+    }
+
+    impl SemanticDb for TestDb {
+        fn resolve_module(&self, name: ModuleName) -> Option<Module> {
+            resolve_module(self, name)
+        }
+
+        fn file_to_module(&self, file_id: FileId) -> Option<Module> {
+            file_to_module(self, file_id)
+        }
+
+        fn path_to_module(&self, path: &Path) -> Option<Module> {
+            path_to_module(self, path)
+        }
+
+        fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type {
+            infer_symbol_type(self, file_id, symbol_id)
+        }
+
+        fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable> {
+            symbol_table(self, file_id)
+        }
+
+        fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)> {
+            add_module(self, path)
+        }
+
+        fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>) {
+            set_module_search_paths(self, paths);
+        }
+    }
+}

crates/red_knot/src/files.rs

@@ -0,0 +1,148 @@
+use std::fmt::{Debug, Formatter};
+use std::hash::{Hash, Hasher};
+use std::path::Path;
+use std::sync::Arc;
+
+use hashbrown::hash_map::RawEntryMut;
+use parking_lot::RwLock;
+use rustc_hash::FxHasher;
+
+use ruff_index::{newtype_index, IndexVec};
+
+type Map<K, V> = hashbrown::HashMap<K, V, ()>;
+
+#[newtype_index]
+pub struct FileId;
+
+// TODO we'll need a higher level virtual file system abstraction that allows testing if a file exists
+// or retrieving its content (ideally lazily and in a way that the memory can be retained later)
+// I suspect that we'll end up with a FileSystem trait and our own Path abstraction.
+#[derive(Clone, Default)]
+pub struct Files {
+    inner: Arc<RwLock<FilesInner>>,
+}
+
+impl Files {
+    #[tracing::instrument(level = "debug", skip(self))]
+    pub fn intern(&self, path: &Path) -> FileId {
+        self.inner.write().intern(path)
+    }
+
+    pub fn try_get(&self, path: &Path) -> Option<FileId> {
+        self.inner.read().try_get(path)
+    }
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    pub fn path(&self, id: FileId) -> Arc<Path> {
+        self.inner.read().path(id)
+    }
+}
+
+impl Debug for Files {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let files = self.inner.read();
+        let mut debug = f.debug_map();
+        for item in files.iter() {
+            debug.entry(&item.0, &item.1);
+        }
+
+        debug.finish()
+    }
+}
+
+impl PartialEq for Files {
+    fn eq(&self, other: &Self) -> bool {
+        self.inner.read().eq(&other.inner.read())
+    }
+}
+
+impl Eq for Files {}
+
+#[derive(Default)]
+struct FilesInner {
+    by_path: Map<FileId, ()>,
+    // TODO should we use a map here to reclaim the space for removed files?
+    // TODO I think we should use our own path abstraction here to avoid having to normalize paths
+    // and dealing with non-utf paths everywhere.
+    by_id: IndexVec<FileId, Arc<Path>>,
+}
+
+impl FilesInner {
+    /// Inserts the path and returns a new id for it or returns the id if it is an existing path.
+    // TODO should this accept Path or PathBuf?
+    pub(crate) fn intern(&mut self, path: &Path) -> FileId {
+        let mut hasher = FxHasher::default();
+        path.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        let entry = self
+            .by_path
+            .raw_entry_mut()
+            .from_hash(hash, |existing_file| &*self.by_id[*existing_file] == path);
+
+        match entry {
+            RawEntryMut::Occupied(entry) => *entry.key(),
+            RawEntryMut::Vacant(entry) => {
+                let id = self.by_id.push(Arc::from(path));
+                entry.insert_with_hasher(hash, id, (), |_| hash);
+                id
+            }
+        }
+    }
+
+    pub(crate) fn try_get(&self, path: &Path) -> Option<FileId> {
+        let mut hasher = FxHasher::default();
+        path.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        Some(
+            *self
+                .by_path
+                .raw_entry()
+                .from_hash(hash, |existing_file| &*self.by_id[*existing_file] == path)?
+                .0,
+        )
+    }
+
+    /// Returns the path for the file with the given id.
+    pub(crate) fn path(&self, id: FileId) -> Arc<Path> {
+        self.by_id[id].clone()
+    }
+
+    pub(crate) fn iter(&self) -> impl Iterator<Item = (FileId, Arc<Path>)> + '_ {
+        self.by_path.keys().map(|id| (*id, self.by_id[*id].clone()))
+    }
+}
+
+impl PartialEq for FilesInner {
+    fn eq(&self, other: &Self) -> bool {
+        self.by_id == other.by_id
+    }
+}
+
+impl Eq for FilesInner {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    #[test]
+    fn insert_path_twice_same_id() {
+        let files = Files::default();
+        let path = PathBuf::from("foo/bar");
+        let id1 = files.intern(&path);
+        let id2 = files.intern(&path);
+        assert_eq!(id1, id2);
+    }
+
+    #[test]
+    fn insert_different_paths_different_ids() {
+        let files = Files::default();
+        let path1 = PathBuf::from("foo/bar");
+        let path2 = PathBuf::from("foo/bar/baz");
+        let id1 = files.intern(&path1);
+        let id2 = files.intern(&path2);
+        assert_ne!(id1, id2);
+    }
+}

crates/red_knot/src/hir.rs

@@ -0,0 +1,67 @@
+//! Key observations
+//!
+//! The HIR avoids allocations to large extends by:
+//! * Using an arena per node type
+//! * using ids and id ranges to reference items.
+//!
+//! Using separate arena per node type has the advantage that the IDs are relatively stable, because
+//! they only change when a node of the same kind has been added or removed. (What's unclear is if that matters or if
+//! it still triggers a re-compute because the AST-id in the node has changed).
+//!
+//! The HIR does not store all details. It mainly stores the *public* interface. There's a reference
+//! back to the AST node to get more details.
+//!
+//!
+
+use crate::ast_ids::{HasAstId, TypedAstId};
+use crate::files::FileId;
+use std::fmt::Formatter;
+use std::hash::{Hash, Hasher};
+
+pub struct HirAstId<N: HasAstId> {
+    file_id: FileId,
+    node_id: TypedAstId<N>,
+}
+
+impl<N: HasAstId> Copy for HirAstId<N> {}
+impl<N: HasAstId> Clone for HirAstId<N> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<N: HasAstId> PartialEq for HirAstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.file_id == other.file_id && self.node_id == other.node_id
+    }
+}
+
+impl<N: HasAstId> Eq for HirAstId<N> {}
+
+impl<N: HasAstId> std::fmt::Debug for HirAstId<N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("HirAstId")
+            .field("file_id", &self.file_id)
+            .field("node_id", &self.node_id)
+            .finish()
+    }
+}
+
+impl<N: HasAstId> Hash for HirAstId<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.file_id.hash(state);
+        self.node_id.hash(state);
+    }
+}
+
+impl<N: HasAstId> HirAstId<N> {
+    pub fn upcast<M: HasAstId>(self) -> HirAstId<M>
+    where
+        N: Into<M>,
+    {
+        HirAstId {
+            file_id: self.file_id,
+            node_id: self.node_id.upcast(),
+        }
+    }
+}

crates/red_knot/src/hir/definition.rs

@@ -0,0 +1,556 @@
+use std::ops::{Index, Range};
+
+use ruff_index::{newtype_index, IndexVec};
+use ruff_python_ast::visitor::preorder;
+use ruff_python_ast::visitor::preorder::PreorderVisitor;
+use ruff_python_ast::{
+    Decorator, ExceptHandler, ExceptHandlerExceptHandler, Expr, MatchCase, ModModule, Stmt,
+    StmtAnnAssign, StmtAssign, StmtClassDef, StmtFunctionDef, StmtGlobal, StmtImport,
+    StmtImportFrom, StmtNonlocal, StmtTypeAlias, TypeParam, TypeParamParamSpec, TypeParamTypeVar,
+    TypeParamTypeVarTuple, WithItem,
+};
+
+use crate::ast_ids::{AstIds, HasAstId};
+use crate::files::FileId;
+use crate::hir::HirAstId;
+use crate::Name;
+
+#[newtype_index]
+pub struct FunctionId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Function {
+    ast_id: HirAstId<StmtFunctionDef>,
+    name: Name,
+    parameters: Range<ParameterId>,
+    type_parameters: Range<TypeParameterId>, // TODO: type_parameters, return expression, decorators
+}
+
+#[newtype_index]
+pub struct ParameterId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Parameter {
+    kind: ParameterKind,
+    name: Name,
+    default: Option<()>, // TODO use expression HIR
+    ast_id: HirAstId<ruff_python_ast::Parameter>,
+}
+
+// TODO or should `Parameter` be an enum?
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub enum ParameterKind {
+    PositionalOnly,
+    Arguments,
+    Vararg,
+    KeywordOnly,
+    Kwarg,
+}
+
+#[newtype_index]
+pub struct ClassId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Class {
+    name: Name,
+    ast_id: HirAstId<StmtClassDef>,
+    // TODO type parameters, inheritance, decorators, members
+}
+
+#[newtype_index]
+pub struct AssignmentId;
+
+// This can have more than one name...
+// but that means we can't implement `name()` on `ModuleItem`.
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Assignment {
+    // TODO: Handle multiple names  / targets
+    name: Name,
+    ast_id: HirAstId<StmtAssign>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct AnnotatedAssignment {
+    name: Name,
+    ast_id: HirAstId<StmtAnnAssign>,
+}
+
+#[newtype_index]
+pub struct AnnotatedAssignmentId;
+
+#[newtype_index]
+pub struct TypeAliasId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeAlias {
+    name: Name,
+    ast_id: HirAstId<StmtTypeAlias>,
+    parameters: Range<TypeParameterId>,
+}
+
+#[newtype_index]
+pub struct TypeParameterId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum TypeParameter {
+    TypeVar(TypeParameterTypeVar),
+    ParamSpec(TypeParameterParamSpec),
+    TypeVarTuple(TypeParameterTypeVarTuple),
+}
+
+impl TypeParameter {
+    pub fn ast_id(&self) -> HirAstId<TypeParam> {
+        match self {
+            TypeParameter::TypeVar(type_var) => type_var.ast_id.upcast(),
+            TypeParameter::ParamSpec(param_spec) => param_spec.ast_id.upcast(),
+            TypeParameter::TypeVarTuple(type_var_tuple) => type_var_tuple.ast_id.upcast(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterTypeVar {
+    name: Name,
+    ast_id: HirAstId<TypeParamTypeVar>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterParamSpec {
+    name: Name,
+    ast_id: HirAstId<TypeParamParamSpec>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterTypeVarTuple {
+    name: Name,
+    ast_id: HirAstId<TypeParamTypeVarTuple>,
+}
+
+#[newtype_index]
+pub struct GlobalId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Global {
+    // TODO track names
+    ast_id: HirAstId<StmtGlobal>,
+}
+
+#[newtype_index]
+pub struct NonLocalId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct NonLocal {
+    // TODO track names
+    ast_id: HirAstId<StmtNonlocal>,
+}
+
+pub enum DefinitionId {
+    Function(FunctionId),
+    Parameter(ParameterId),
+    Class(ClassId),
+    Assignment(AssignmentId),
+    AnnotatedAssignment(AnnotatedAssignmentId),
+    Global(GlobalId),
+    NonLocal(NonLocalId),
+    TypeParameter(TypeParameterId),
+    TypeAlias(TypeAlias),
+}
+
+pub enum DefinitionItem {
+    Function(Function),
+    Parameter(Parameter),
+    Class(Class),
+    Assignment(Assignment),
+    AnnotatedAssignment(AnnotatedAssignment),
+    Global(Global),
+    NonLocal(NonLocal),
+    TypeParameter(TypeParameter),
+    TypeAlias(TypeAlias),
+}
+
+// The closest is rust-analyzers item-tree. It only represents "Items" which make the public interface of a module
+// (it excludes any other statement or expressions). rust-analyzer uses it as the main input to the name resolution
+// algorithm
+// > It is the input to the name resolution algorithm, as well as to the queries defined in `adt.rs`,
+// > `data.rs`, and most things in `attr.rs`.
+//
+// > One important purpose of this layer is to provide an "invalidation barrier" for incremental
+// > computations: when typing inside an item body, the `ItemTree` of the modified file is typically
+// > unaffected, so we don't have to recompute name resolution results or item data (see `data.rs`).
+//
+// I haven't fully figured this out but I think that this composes the "public" interface of a module?
+// But maybe that's too optimistic.
+//
+//
+#[derive(Debug, Clone, Default, Eq, PartialEq)]
+pub struct Definitions {
+    functions: IndexVec<FunctionId, Function>,
+    parameters: IndexVec<ParameterId, Parameter>,
+    classes: IndexVec<ClassId, Class>,
+    assignments: IndexVec<AssignmentId, Assignment>,
+    annotated_assignments: IndexVec<AnnotatedAssignmentId, AnnotatedAssignment>,
+    type_aliases: IndexVec<TypeAliasId, TypeAlias>,
+    type_parameters: IndexVec<TypeParameterId, TypeParameter>,
+    globals: IndexVec<GlobalId, Global>,
+    non_locals: IndexVec<NonLocalId, NonLocal>,
+}
+
+impl Definitions {
+    pub fn from_module(module: &ModModule, ast_ids: &AstIds, file_id: FileId) -> Self {
+        let mut visitor = DefinitionsVisitor {
+            definitions: Definitions::default(),
+            ast_ids,
+            file_id,
+        };
+
+        visitor.visit_body(&module.body);
+
+        visitor.definitions
+    }
+}
+
+impl Index<FunctionId> for Definitions {
+    type Output = Function;
+
+    fn index(&self, index: FunctionId) -> &Self::Output {
+        &self.functions[index]
+    }
+}
+
+impl Index<ParameterId> for Definitions {
+    type Output = Parameter;
+
+    fn index(&self, index: ParameterId) -> &Self::Output {
+        &self.parameters[index]
+    }
+}
+
+impl Index<ClassId> for Definitions {
+    type Output = Class;
+
+    fn index(&self, index: ClassId) -> &Self::Output {
+        &self.classes[index]
+    }
+}
+
+impl Index<AssignmentId> for Definitions {
+    type Output = Assignment;
+
+    fn index(&self, index: AssignmentId) -> &Self::Output {
+        &self.assignments[index]
+    }
+}
+
+impl Index<AnnotatedAssignmentId> for Definitions {
+    type Output = AnnotatedAssignment;
+
+    fn index(&self, index: AnnotatedAssignmentId) -> &Self::Output {
+        &self.annotated_assignments[index]
+    }
+}
+
+impl Index<TypeAliasId> for Definitions {
+    type Output = TypeAlias;
+
+    fn index(&self, index: TypeAliasId) -> &Self::Output {
+        &self.type_aliases[index]
+    }
+}
+
+impl Index<GlobalId> for Definitions {
+    type Output = Global;
+
+    fn index(&self, index: GlobalId) -> &Self::Output {
+        &self.globals[index]
+    }
+}
+
+impl Index<NonLocalId> for Definitions {
+    type Output = NonLocal;
+
+    fn index(&self, index: NonLocalId) -> &Self::Output {
+        &self.non_locals[index]
+    }
+}
+
+impl Index<TypeParameterId> for Definitions {
+    type Output = TypeParameter;
+
+    fn index(&self, index: TypeParameterId) -> &Self::Output {
+        &self.type_parameters[index]
+    }
+}
+
+struct DefinitionsVisitor<'a> {
+    definitions: Definitions,
+    ast_ids: &'a AstIds,
+    file_id: FileId,
+}
+
+impl DefinitionsVisitor<'_> {
+    fn ast_id<N: HasAstId>(&self, node: &N) -> HirAstId<N> {
+        HirAstId {
+            file_id: self.file_id,
+            node_id: self.ast_ids.ast_id(node),
+        }
+    }
+
+    fn lower_function_def(&mut self, function: &StmtFunctionDef) -> FunctionId {
+        let name = Name::new(&function.name);
+
+        let first_type_parameter_id = self.definitions.type_parameters.next_index();
+        let mut last_type_parameter_id = first_type_parameter_id;
+
+        if let Some(type_params) = &function.type_params {
+            for parameter in &type_params.type_params {
+                let id = self.lower_type_parameter(parameter);
+                last_type_parameter_id = id;
+            }
+        }
+
+        let parameters = self.lower_parameters(&function.parameters);
+
+        self.definitions.functions.push(Function {
+            name,
+            ast_id: self.ast_id(function),
+            parameters,
+            type_parameters: first_type_parameter_id..last_type_parameter_id,
+        })
+    }
+
+    fn lower_parameters(&mut self, parameters: &ruff_python_ast::Parameters) -> Range<ParameterId> {
+        let first_parameter_id = self.definitions.parameters.next_index();
+        let mut last_parameter_id = first_parameter_id;
+
+        for parameter in &parameters.posonlyargs {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::PositionalOnly,
+                name: Name::new(&parameter.parameter.name),
+                default: None,
+                ast_id: self.ast_id(&parameter.parameter),
+            });
+        }
+
+        if let Some(vararg) = &parameters.vararg {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::Vararg,
+                name: Name::new(&vararg.name),
+                default: None,
+                ast_id: self.ast_id(vararg),
+            });
+        }
+
+        for parameter in &parameters.kwonlyargs {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::KeywordOnly,
+                name: Name::new(&parameter.parameter.name),
+                default: None,
+                ast_id: self.ast_id(&parameter.parameter),
+            });
+        }
+
+        if let Some(kwarg) = &parameters.kwarg {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::KeywordOnly,
+                name: Name::new(&kwarg.name),
+                default: None,
+                ast_id: self.ast_id(kwarg),
+            });
+        }
+
+        first_parameter_id..last_parameter_id
+    }
+
+    fn lower_class_def(&mut self, class: &StmtClassDef) -> ClassId {
+        let name = Name::new(&class.name);
+
+        self.definitions.classes.push(Class {
+            name,
+            ast_id: self.ast_id(class),
+        })
+    }
+
+    fn lower_assignment(&mut self, assignment: &StmtAssign) {
+        // FIXME handle multiple names
+        if let Some(Expr::Name(name)) = assignment.targets.first() {
+            self.definitions.assignments.push(Assignment {
+                name: Name::new(&name.id),
+                ast_id: self.ast_id(assignment),
+            });
+        }
+    }
+
+    fn lower_annotated_assignment(&mut self, annotated_assignment: &StmtAnnAssign) {
+        if let Expr::Name(name) = &*annotated_assignment.target {
+            self.definitions
+                .annotated_assignments
+                .push(AnnotatedAssignment {
+                    name: Name::new(&name.id),
+                    ast_id: self.ast_id(annotated_assignment),
+                });
+        }
+    }
+
+    fn lower_type_alias(&mut self, type_alias: &StmtTypeAlias) {
+        if let Expr::Name(name) = &*type_alias.name {
+            let name = Name::new(&name.id);
+
+            let lower_parameters_id = self.definitions.type_parameters.next_index();
+            let mut last_parameter_id = lower_parameters_id;
+
+            if let Some(type_params) = &type_alias.type_params {
+                for type_parameter in &type_params.type_params {
+                    let id = self.lower_type_parameter(type_parameter);
+                    last_parameter_id = id;
+                }
+            }
+
+            self.definitions.type_aliases.push(TypeAlias {
+                name,
+                ast_id: self.ast_id(type_alias),
+                parameters: lower_parameters_id..last_parameter_id,
+            });
+        }
+    }
+
+    fn lower_type_parameter(&mut self, type_parameter: &TypeParam) -> TypeParameterId {
+        match type_parameter {
+            TypeParam::TypeVar(type_var) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::TypeVar(TypeParameterTypeVar {
+                        name: Name::new(&type_var.name),
+                        ast_id: self.ast_id(type_var),
+                    }))
+            }
+            TypeParam::ParamSpec(param_spec) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::ParamSpec(TypeParameterParamSpec {
+                        name: Name::new(&param_spec.name),
+                        ast_id: self.ast_id(param_spec),
+                    }))
+            }
+            TypeParam::TypeVarTuple(type_var_tuple) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::TypeVarTuple(TypeParameterTypeVarTuple {
+                        name: Name::new(&type_var_tuple.name),
+                        ast_id: self.ast_id(type_var_tuple),
+                    }))
+            }
+        }
+    }
+
+    fn lower_import(&mut self, _import: &StmtImport) {
+        // TODO
+    }
+
+    fn lower_import_from(&mut self, _import_from: &StmtImportFrom) {
+        // TODO
+    }
+
+    fn lower_global(&mut self, global: &StmtGlobal) -> GlobalId {
+        self.definitions.globals.push(Global {
+            ast_id: self.ast_id(global),
+        })
+    }
+
+    fn lower_non_local(&mut self, non_local: &StmtNonlocal) -> NonLocalId {
+        self.definitions.non_locals.push(NonLocal {
+            ast_id: self.ast_id(non_local),
+        })
+    }
+
+    fn lower_except_handler(&mut self, _except_handler: &ExceptHandlerExceptHandler) {
+        // TODO
+    }
+
+    fn lower_with_item(&mut self, _with_item: &WithItem) {
+        // TODO
+    }
+
+    fn lower_match_case(&mut self, _match_case: &MatchCase) {
+        // TODO
+    }
+}
+
+impl PreorderVisitor<'_> for DefinitionsVisitor<'_> {
+    fn visit_stmt(&mut self, stmt: &Stmt) {
+        match stmt {
+            // Definition statements
+            Stmt::FunctionDef(definition) => {
+                self.lower_function_def(definition);
+                self.visit_body(&definition.body);
+            }
+            Stmt::ClassDef(definition) => {
+                self.lower_class_def(definition);
+                self.visit_body(&definition.body);
+            }
+            Stmt::Assign(assignment) => {
+                self.lower_assignment(assignment);
+            }
+            Stmt::AnnAssign(annotated_assignment) => {
+                self.lower_annotated_assignment(annotated_assignment);
+            }
+            Stmt::TypeAlias(type_alias) => {
+                self.lower_type_alias(type_alias);
+            }
+
+            Stmt::Import(import) => self.lower_import(import),
+            Stmt::ImportFrom(import_from) => self.lower_import_from(import_from),
+            Stmt::Global(global) => {
+                self.lower_global(global);
+            }
+            Stmt::Nonlocal(non_local) => {
+                self.lower_non_local(non_local);
+            }
+
+            // Visit the compound statement bodies because they can contain other definitions.
+            Stmt::For(_)
+            | Stmt::While(_)
+            | Stmt::If(_)
+            | Stmt::With(_)
+            | Stmt::Match(_)
+            | Stmt::Try(_) => {
+                preorder::walk_stmt(self, stmt);
+            }
+
+            // Skip over simple statements because they can't contain any other definitions.
+            Stmt::Return(_)
+            | Stmt::Delete(_)
+            | Stmt::AugAssign(_)
+            | Stmt::Raise(_)
+            | Stmt::Assert(_)
+            | Stmt::Expr(_)
+            | Stmt::Pass(_)
+            | Stmt::Break(_)
+            | Stmt::Continue(_)
+            | Stmt::IpyEscapeCommand(_) => {
+                // No op
+            }
+        }
+    }
+
+    fn visit_expr(&mut self, _: &'_ Expr) {}
+
+    fn visit_decorator(&mut self, _decorator: &'_ Decorator) {}
+
+    fn visit_except_handler(&mut self, except_handler: &'_ ExceptHandler) {
+        match except_handler {
+            ExceptHandler::ExceptHandler(except_handler) => {
+                self.lower_except_handler(except_handler);
+            }
+        }
+    }
+
+    fn visit_with_item(&mut self, with_item: &'_ WithItem) {
+        self.lower_with_item(with_item);
+    }
+
+    fn visit_match_case(&mut self, match_case: &'_ MatchCase) {
+        self.lower_match_case(match_case);
+        self.visit_body(&match_case.body);
+    }
+}

crates/red_knot/src/lib.rs

@@ -0,0 +1,102 @@
+use std::hash::BuildHasherDefault;
+use std::ops::Deref;
+use std::path::{Path, PathBuf};
+
+use rustc_hash::{FxHashSet, FxHasher};
+
+use crate::files::FileId;
+
+pub mod ast_ids;
+pub mod cache;
+pub mod cancellation;
+pub mod db;
+pub mod files;
+pub mod hir;
+pub mod lint;
+pub mod module;
+mod parse;
+pub mod program;
+pub mod source;
+mod symbols;
+mod types;
+pub mod watch;
+
+pub(crate) type FxDashMap<K, V> = dashmap::DashMap<K, V, BuildHasherDefault<FxHasher>>;
+#[allow(unused)]
+pub(crate) type FxDashSet<V> = dashmap::DashSet<V, BuildHasherDefault<FxHasher>>;
+pub(crate) type FxIndexSet<V> = indexmap::set::IndexSet<V, BuildHasherDefault<FxHasher>>;
+
+#[derive(Debug)]
+pub struct Workspace {
+    /// TODO this should be a resolved path. We should probably use a newtype wrapper that guarantees that
+    /// PATH is a UTF-8 path and is normalized.
+    root: PathBuf,
+    /// The files that are open in the workspace.
+    ///
+    /// * Editor: The files that are actively being edited in the editor (the user has a tab open with the file).
+    /// * CLI: The resolved files passed as arguments to the CLI.
+    open_files: FxHashSet<FileId>,
+}
+
+impl Workspace {
+    pub fn new(root: PathBuf) -> Self {
+        Self {
+            root,
+            open_files: FxHashSet::default(),
+        }
+    }
+
+    pub fn root(&self) -> &Path {
+        self.root.as_path()
+    }
+
+    // TODO having the content in workspace feels wrong.
+    pub fn open_file(&mut self, file_id: FileId) {
+        self.open_files.insert(file_id);
+    }
+
+    pub fn close_file(&mut self, file_id: FileId) {
+        self.open_files.remove(&file_id);
+    }
+
+    // TODO introduce an `OpenFile` type instead of using an anonymous tuple.
+    pub fn open_files(&self) -> impl Iterator<Item = FileId> + '_ {
+        self.open_files.iter().copied()
+    }
+
+    pub fn is_file_open(&self, file_id: FileId) -> bool {
+        self.open_files.contains(&file_id)
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct Name(smol_str::SmolStr);
+
+impl Name {
+    #[inline]
+    pub fn new(name: &str) -> Self {
+        Self(smol_str::SmolStr::new(name))
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+}
+
+impl Deref for Name {
+    type Target = str;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.as_str()
+    }
+}
+
+impl<T> From<T> for Name
+where
+    T: Into<smol_str::SmolStr>,
+{
+    fn from(value: T) -> Self {
+        Self(value.into())
+    }
+}

crates/red_knot/src/lint.rs

@@ -0,0 +1,125 @@
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::StringLiteral;
+
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SourceDb, SourceJar};
+use crate::files::FileId;
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn lint_syntax<Db>(db: &Db, file_id: FileId) -> Diagnostics
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let storage = &db.jar().lint_syntax;
+
+    storage.get(&file_id, |file_id| {
+        let mut diagnostics = Vec::new();
+
+        let source = db.source(*file_id);
+        lint_lines(source.text(), &mut diagnostics);
+
+        let parsed = db.parse(*file_id);
+
+        if parsed.errors().is_empty() {
+            let ast = parsed.ast();
+
+            let mut visitor = SyntaxLintVisitor {
+                diagnostics,
+                source: source.text(),
+            };
+            visitor.visit_body(&ast.body);
+            diagnostics = visitor.diagnostics;
+        } else {
+            diagnostics.extend(parsed.errors().iter().map(std::string::ToString::to_string));
+        }
+
+        Diagnostics::from(diagnostics)
+    })
+}
+
+pub(crate) fn lint_lines(source: &str, diagnostics: &mut Vec<String>) {
+    for (line_number, line) in source.lines().enumerate() {
+        if line.len() < 88 {
+            continue;
+        }
+
+        let char_count = line.chars().count();
+        if char_count > 88 {
+            diagnostics.push(format!(
+                "Line {} is too long ({} characters)",
+                line_number + 1,
+                char_count
+            ));
+        }
+    }
+}
+
+#[derive(Debug)]
+struct SyntaxLintVisitor<'a> {
+    diagnostics: Vec<String>,
+    source: &'a str,
+}
+
+impl Visitor<'_> for SyntaxLintVisitor<'_> {
+    fn visit_string_literal(&mut self, string_literal: &'_ StringLiteral) {
+        // A very naive implementation of use double quotes
+        let text = &self.source[string_literal.range];
+
+        if text.starts_with('\'') {
+            self.diagnostics
+                .push("Use double quotes for strings".to_string());
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum Diagnostics {
+    Empty,
+    List(Arc<Vec<String>>),
+}
+
+impl Diagnostics {
+    pub fn as_slice(&self) -> &[String] {
+        match self {
+            Diagnostics::Empty => &[],
+            Diagnostics::List(list) => list.as_slice(),
+        }
+    }
+}
+
+impl Deref for Diagnostics {
+    type Target = [String];
+    fn deref(&self) -> &Self::Target {
+        self.as_slice()
+    }
+}
+
+impl From<Vec<String>> for Diagnostics {
+    fn from(value: Vec<String>) -> Self {
+        if value.is_empty() {
+            Diagnostics::Empty
+        } else {
+            Diagnostics::List(Arc::new(value))
+        }
+    }
+}
+
+#[derive(Default, Debug)]
+pub struct LintSyntaxStorage(KeyValueCache<FileId, Diagnostics>);
+
+impl Deref for LintSyntaxStorage {
+    type Target = KeyValueCache<FileId, Diagnostics>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for LintSyntaxStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/logging.rs

@@ -1,254 +0,0 @@
-//! Sets up logging for Red Knot
-
-use anyhow::Context;
-use colored::Colorize;
-use std::fmt;
-use std::fs::File;
-use std::io::BufWriter;
-use tracing::{Event, Subscriber};
-use tracing_subscriber::filter::LevelFilter;
-use tracing_subscriber::fmt::format::Writer;
-use tracing_subscriber::fmt::{FmtContext, FormatEvent, FormatFields};
-use tracing_subscriber::registry::LookupSpan;
-use tracing_subscriber::EnvFilter;
-
-/// Logging flags to `#[command(flatten)]` into your CLI
-#[derive(clap::Args, Debug, Clone, Default)]
-#[command(about = None, long_about = None)]
-pub(crate) struct Verbosity {
-    #[arg(
-        long,
-        short = 'v',
-        help = "Use verbose output (or `-vv` and `-vvv` for more verbose output)",
-        action = clap::ArgAction::Count,
-        global = true,
-    )]
-    verbose: u8,
-}
-
-impl Verbosity {
-    /// Returns the verbosity level based on the number of `-v` flags.
-    ///
-    /// Returns `None` if the user did not specify any verbosity flags.
-    pub(crate) fn level(&self) -> VerbosityLevel {
-        match self.verbose {
-            0 => VerbosityLevel::Default,
-            1 => VerbosityLevel::Verbose,
-            2 => VerbosityLevel::ExtraVerbose,
-            _ => VerbosityLevel::Trace,
-        }
-    }
-}
-
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-pub(crate) enum VerbosityLevel {
-    /// Default output level. Only shows Ruff and Red Knot events up to the [`WARN`](tracing::Level::WARN).
-    Default,
-
-    /// Enables verbose output. Emits Ruff and Red Knot events up to the [`INFO`](tracing::Level::INFO).
-    /// Corresponds to `-v`.
-    Verbose,
-
-    /// Enables a more verbose tracing format and emits Ruff and Red Knot events up to [`DEBUG`](tracing::Level::DEBUG).
-    /// Corresponds to `-vv`
-    ExtraVerbose,
-
-    /// Enables all tracing events and uses a tree-like output format. Corresponds to `-vvv`.
-    Trace,
-}
-
-impl VerbosityLevel {
-    const fn level_filter(self) -> LevelFilter {
-        match self {
-            VerbosityLevel::Default => LevelFilter::WARN,
-            VerbosityLevel::Verbose => LevelFilter::INFO,
-            VerbosityLevel::ExtraVerbose => LevelFilter::DEBUG,
-            VerbosityLevel::Trace => LevelFilter::TRACE,
-        }
-    }
-
-    pub(crate) const fn is_trace(self) -> bool {
-        matches!(self, VerbosityLevel::Trace)
-    }
-
-    pub(crate) const fn is_extra_verbose(self) -> bool {
-        matches!(self, VerbosityLevel::ExtraVerbose)
-    }
-}
-
-pub(crate) fn setup_tracing(level: VerbosityLevel) -> anyhow::Result<TracingGuard> {
-    use tracing_subscriber::prelude::*;
-
-    // The `RED_KNOT_LOG` environment variable overrides the default log level.
-    let filter = if let Ok(log_env_variable) = std::env::var("RED_KNOT_LOG") {
-        EnvFilter::builder()
-            .parse(log_env_variable)
-            .context("Failed to parse directives specified in RED_KNOT_LOG environment variable.")?
-    } else {
-        match level {
-            VerbosityLevel::Default => {
-                // Show warning traces
-                EnvFilter::default().add_directive(LevelFilter::WARN.into())
-            }
-            level => {
-                let level_filter = level.level_filter();
-
-                // Show info|debug|trace events, but allow `RED_KNOT_LOG` to override
-                let filter = EnvFilter::default().add_directive(
-                    format!("red_knot={level_filter}")
-                        .parse()
-                        .expect("Hardcoded directive to be valid"),
-                );
-
-                filter.add_directive(
-                    format!("ruff={level_filter}")
-                        .parse()
-                        .expect("Hardcoded directive to be valid"),
-                )
-            }
-        }
-    };
-
-    let (profiling_layer, guard) = setup_profile();
-
-    let registry = tracing_subscriber::registry()
-        .with(filter)
-        .with(profiling_layer);
-
-    if level.is_trace() {
-        let subscriber = registry.with(
-            tracing_tree::HierarchicalLayer::default()
-                .with_indent_lines(true)
-                .with_indent_amount(2)
-                .with_bracketed_fields(true)
-                .with_thread_ids(true)
-                .with_targets(true)
-                .with_writer(std::io::stderr)
-                .with_timer(tracing_tree::time::Uptime::default()),
-        );
-
-        subscriber.init();
-    } else {
-        let subscriber = registry.with(
-            tracing_subscriber::fmt::layer()
-                .event_format(RedKnotFormat {
-                    display_level: true,
-                    display_timestamp: level.is_extra_verbose(),
-                    show_spans: false,
-                })
-                .with_writer(std::io::stderr),
-        );
-
-        subscriber.init();
-    }
-
-    Ok(TracingGuard {
-        _flame_guard: guard,
-    })
-}
-
-#[allow(clippy::type_complexity)]
-fn setup_profile<S>() -> (
-    Option<tracing_flame::FlameLayer<S, BufWriter<File>>>,
-    Option<tracing_flame::FlushGuard<BufWriter<File>>>,
-)
-where
-    S: Subscriber + for<'span> LookupSpan<'span>,
-{
-    if let Ok("1" | "true") = std::env::var("RED_KNOT_LOG_PROFILE").as_deref() {
-        let (layer, guard) = tracing_flame::FlameLayer::with_file("tracing.folded")
-            .expect("Flame layer to be created");
-        (Some(layer), Some(guard))
-    } else {
-        (None, None)
-    }
-}
-
-pub(crate) struct TracingGuard {
-    _flame_guard: Option<tracing_flame::FlushGuard<BufWriter<File>>>,
-}
-
-struct RedKnotFormat {
-    display_timestamp: bool,
-    display_level: bool,
-    show_spans: bool,
-}
-
-/// See <https://docs.rs/tracing-subscriber/0.3.18/src/tracing_subscriber/fmt/format/mod.rs.html#1026-1156>
-impl<S, N> FormatEvent<S, N> for RedKnotFormat
-where
-    S: Subscriber + for<'a> LookupSpan<'a>,
-    N: for<'a> FormatFields<'a> + 'static,
-{
-    fn format_event(
-        &self,
-        ctx: &FmtContext<'_, S, N>,
-        mut writer: Writer<'_>,
-        event: &Event<'_>,
-    ) -> fmt::Result {
-        let meta = event.metadata();
-        let ansi = writer.has_ansi_escapes();
-
-        if self.display_timestamp {
-            let timestamp = chrono::Local::now()
-                .format("%Y-%m-%d %H:%M:%S.%f")
-                .to_string();
-            if ansi {
-                write!(writer, "{} ", timestamp.dimmed())?;
-            } else {
-                write!(
-                    writer,
-                    "{} ",
-                    chrono::Local::now().format("%Y-%m-%d %H:%M:%S.%f")
-                )?;
-            }
-        }
-
-        if self.display_level {
-            let level = meta.level();
-            // Same colors as tracing
-            if ansi {
-                let formatted_level = level.to_string();
-                match *level {
-                    tracing::Level::TRACE => {
-                        write!(writer, "{} ", formatted_level.purple().bold())?;
-                    }
-                    tracing::Level::DEBUG => write!(writer, "{} ", formatted_level.blue().bold())?,
-                    tracing::Level::INFO => write!(writer, "{} ", formatted_level.green().bold())?,
-                    tracing::Level::WARN => write!(writer, "{} ", formatted_level.yellow().bold())?,
-                    tracing::Level::ERROR => write!(writer, "{} ", level.to_string().red().bold())?,
-                }
-            } else {
-                write!(writer, "{level} ")?;
-            }
-        }
-
-        if self.show_spans {
-            let span = event.parent();
-            let mut seen = false;
-
-            let span = span
-                .and_then(|id| ctx.span(id))
-                .or_else(|| ctx.lookup_current());
-
-            let scope = span.into_iter().flat_map(|span| span.scope().from_root());
-
-            for span in scope {
-                seen = true;
-                if ansi {
-                    write!(writer, "{}:", span.metadata().name().bold())?;
-                } else {
-                    write!(writer, "{}:", span.metadata().name())?;
-                }
-            }
-
-            if seen {
-                writer.write_char(' ')?;
-            }
-        }
-
-        ctx.field_format().format_fields(writer.by_ref(), event)?;
-
-        writeln!(writer)
-    }
-}

crates/red_knot/src/main.rs

@@ -1,199 +1,62 @@
-use std::process::{ExitCode, Termination};
+#![allow(clippy::dbg_macro)]
+
+use std::collections::hash_map::Entry;
+use std::path::Path;
 use std::sync::Mutex;
 
-use anyhow::{anyhow, Context};
-use clap::Parser;
-use colored::Colorize;
-use crossbeam::channel as crossbeam_channel;
-use red_knot_python_semantic::SitePackages;
-use red_knot_server::run_server;
-use red_knot_workspace::db::RootDatabase;
-use red_knot_workspace::watch;
-use red_knot_workspace::watch::WorkspaceWatcher;
-use red_knot_workspace::workspace::settings::Configuration;
-use red_knot_workspace::workspace::WorkspaceMetadata;
-use ruff_db::diagnostic::Diagnostic;
-use ruff_db::system::{OsSystem, System, SystemPath, SystemPathBuf};
-use salsa::plumbing::ZalsaDatabase;
-use target_version::TargetVersion;
+use rustc_hash::FxHashMap;
+use tracing::subscriber::Interest;
+use tracing::{Level, Metadata};
+use tracing_subscriber::filter::LevelFilter;
+use tracing_subscriber::layer::{Context, Filter, SubscriberExt};
+use tracing_subscriber::{Layer, Registry};
+use tracing_tree::time::Uptime;
 
-use crate::logging::{setup_tracing, Verbosity};
-
-mod logging;
-mod target_version;
-mod verbosity;
-
-#[derive(Debug, Parser)]
-#[command(
-    author,
-    name = "red-knot",
-    about = "An extremely fast Python type checker."
-)]
-#[command(version)]
-struct Args {
-    #[command(subcommand)]
-    pub(crate) command: Option<Command>,
-
-    #[arg(
-        long,
-        help = "Changes the current working directory.",
-        long_help = "Changes the current working directory before any specified operations. This affects the workspace and configuration discovery.",
-        value_name = "PATH"
-    )]
-    current_directory: Option<SystemPathBuf>,
-
-    #[arg(
-        long,
-        help = "Path to the virtual environment the project uses",
-        long_help = "\
-Path to the virtual environment the project uses. \
-If provided, red-knot will use the `site-packages` directory of this virtual environment \
-to resolve type information for the project's third-party dependencies.",
-        value_name = "PATH"
-    )]
-    venv_path: Option<SystemPathBuf>,
-
-    #[arg(
-        long,
-        value_name = "DIRECTORY",
-        help = "Custom directory to use for stdlib typeshed stubs"
-    )]
-    custom_typeshed_dir: Option<SystemPathBuf>,
-
-    #[arg(
-        long,
-        value_name = "PATH",
-        help = "Additional path to use as a module-resolution source (can be passed multiple times)"
-    )]
-    extra_search_path: Option<Vec<SystemPathBuf>>,
-
-    #[arg(
-        long,
-        help = "Python version to assume when resolving types",
-        value_name = "VERSION"
-    )]
-    target_version: Option<TargetVersion>,
-
-    #[clap(flatten)]
-    verbosity: Verbosity,
-
-    #[arg(
-        long,
-        help = "Run in watch mode by re-running whenever files change",
-        short = 'W'
-    )]
-    watch: bool,
-}
-
-impl Args {
-    fn to_configuration(&self, cli_cwd: &SystemPath) -> Configuration {
-        let mut configuration = Configuration::default();
-
-        if let Some(target_version) = self.target_version {
-            configuration.target_version = Some(target_version.into());
-        }
-
-        if let Some(venv_path) = &self.venv_path {
-            configuration.search_paths.site_packages = Some(SitePackages::Derived {
-                venv_path: SystemPath::absolute(venv_path, cli_cwd),
-            });
-        }
-
-        if let Some(custom_typeshed_dir) = &self.custom_typeshed_dir {
-            configuration.search_paths.custom_typeshed =
-                Some(SystemPath::absolute(custom_typeshed_dir, cli_cwd));
-        }
-
-        if let Some(extra_search_paths) = &self.extra_search_path {
-            configuration.search_paths.extra_paths = extra_search_paths
-                .iter()
-                .map(|path| Some(SystemPath::absolute(path, cli_cwd)))
-                .collect();
-        }
-
-        configuration
-    }
-}
-
-#[derive(Debug, clap::Subcommand)]
-pub enum Command {
-    /// Start the language server
-    Server,
-}
+use red_knot::cancellation::CancellationTokenSource;
+use red_knot::db::{HasJar, SourceDb, SourceJar};
+use red_knot::files::FileId;
+use red_knot::module::{ModuleSearchPath, ModuleSearchPathKind};
+use red_knot::program::check::{CheckError, RayonCheckScheduler};
+use red_knot::program::{FileChange, FileChangeKind, Program};
+use red_knot::watch::FileWatcher;
+use red_knot::Workspace;
 
 #[allow(clippy::print_stdout, clippy::unnecessary_wraps, clippy::print_stderr)]
-pub fn main() -> ExitStatus {
-    run().unwrap_or_else(|error| {
-        use std::io::Write;
+fn main() -> anyhow::Result<()> {
+    setup_tracing();
 
-        // Use `writeln` instead of `eprintln` to avoid panicking when the stderr pipe is broken.
-        let mut stderr = std::io::stderr().lock();
+    let arguments: Vec<_> = std::env::args().collect();
 
-        // This communicates that this isn't a linter error but Red Knot itself hard-errored for
-        // some reason (e.g. failed to resolve the configuration)
-        writeln!(stderr, "{}", "Red Knot failed".red().bold()).ok();
-        // Currently we generally only see one error, but e.g. with io errors when resolving
-        // the configuration it is help to chain errors ("resolving configuration failed" ->
-        // "failed to read file: subdir/pyproject.toml")
-        for cause in error.chain() {
-            writeln!(stderr, "  {} {cause}", "Cause:".bold()).ok();
-        }
-
-        ExitStatus::Error
-    })
-}
-
-fn run() -> anyhow::Result<ExitStatus> {
-    let args = Args::parse_from(std::env::args());
-
-    if matches!(args.command, Some(Command::Server)) {
-        return run_server().map(|()| ExitStatus::Success);
+    if arguments.len() < 2 {
+        eprintln!("Usage: red_knot <path>");
+        return Err(anyhow::anyhow!("Invalid arguments"));
     }
 
-    let verbosity = args.verbosity.level();
-    countme::enable(verbosity.is_trace());
-    let _guard = setup_tracing(verbosity)?;
+    let entry_point = Path::new(&arguments[1]);
 
-    // The base path to which all CLI arguments are relative to.
-    let cli_base_path = {
-        let cwd = std::env::current_dir().context("Failed to get the current working directory")?;
-        SystemPathBuf::from_path_buf(cwd)
-            .map_err(|path| {
-                anyhow!(
-                    "The current working directory `{}` contains non-Unicode characters. Red Knot only supports Unicode paths.",
-                    path.display()
-                )
-            })?
-    };
+    if !entry_point.exists() {
+        eprintln!("The entry point does not exist.");
+        return Err(anyhow::anyhow!("Invalid arguments"));
+    }
 
-    let cwd = args
-        .current_directory
-        .as_ref()
-        .map(|cwd| {
-            if cwd.as_std_path().is_dir() {
-                Ok(SystemPath::absolute(cwd, &cli_base_path))
-            } else {
-                Err(anyhow!(
-                    "Provided current-directory path `{cwd}` is not a directory"
-                ))
-            }
-        })
-        .transpose()?
-        .unwrap_or_else(|| cli_base_path.clone());
+    if !entry_point.is_file() {
+        eprintln!("The entry point is not a file.");
+        return Err(anyhow::anyhow!("Invalid arguments"));
+    }
 
-    let system = OsSystem::new(cwd.clone());
-    let cli_configuration = args.to_configuration(&cwd);
-    let workspace_metadata = WorkspaceMetadata::discover(
-        system.current_directory(),
-        &system,
-        Some(&cli_configuration),
-    )?;
+    let workspace_folder = entry_point.parent().unwrap();
+    let workspace = Workspace::new(workspace_folder.to_path_buf());
 
-    // TODO: Use the `program_settings` to compute the key for the database's persistent
-    //   cache and load the cache if it exists.
-    let mut db = RootDatabase::new(workspace_metadata, system)?;
+    let workspace_search_path = ModuleSearchPath::new(
+        workspace.root().to_path_buf(),
+        ModuleSearchPathKind::FirstParty,
+    );
+    let mut program = Program::new(workspace, vec![workspace_search_path]);
 
-    let (main_loop, main_loop_cancellation_token) = MainLoop::new(cli_configuration);
+    let entry_id = program.file_id(entry_point);
+    program.workspace_mut().open_file(entry_id);
+
+    let (main_loop, main_loop_cancellation_token) = MainLoop::new();
 
     // Listen to Ctrl+C and abort the watch mode.
     let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
@@ -205,162 +68,134 @@ fn run() -> anyhow::Result<ExitStatus> {
         }
     })?;
 
-    let exit_status = if args.watch {
-        main_loop.watch(&mut db)?
-    } else {
-        main_loop.run(&mut db)
-    };
+    let file_changes_notifier = main_loop.file_changes_notifier();
 
-    tracing::trace!("Counts for entire CLI run:\n{}", countme::get_all());
+    // Watch for file changes and re-trigger the analysis.
+    let mut file_watcher = FileWatcher::new(
+        move |changes| {
+            file_changes_notifier.notify(changes);
+        },
+        program.files().clone(),
+    )?;
 
-    std::mem::forget(db);
+    file_watcher.watch_folder(workspace_folder)?;
 
-    Ok(exit_status)
-}
+    main_loop.run(&mut program);
 
-#[derive(Copy, Clone)]
-pub enum ExitStatus {
-    /// Checking was successful and there were no errors.
-    Success = 0,
+    let source_jar: &SourceJar = program.jar();
 
-    /// Checking was successful but there were errors.
-    Failure = 1,
+    dbg!(source_jar.parsed.statistics());
+    dbg!(source_jar.sources.statistics());
 
-    /// Checking failed.
-    Error = 2,
-}
-
-impl Termination for ExitStatus {
-    fn report(self) -> ExitCode {
-        ExitCode::from(self as u8)
-    }
+    Ok(())
 }
 
 struct MainLoop {
-    /// Sender that can be used to send messages to the main loop.
-    sender: crossbeam_channel::Sender<MainLoopMessage>,
-
-    /// Receiver for the messages sent **to** the main loop.
-    receiver: crossbeam_channel::Receiver<MainLoopMessage>,
-
-    /// The file system watcher, if running in watch mode.
-    watcher: Option<WorkspaceWatcher>,
-
-    cli_configuration: Configuration,
+    orchestrator_sender: crossbeam_channel::Sender<OrchestratorMessage>,
+    main_loop_receiver: crossbeam_channel::Receiver<MainLoopMessage>,
 }
 
 impl MainLoop {
-    fn new(cli_configuration: Configuration) -> (Self, MainLoopCancellationToken) {
-        let (sender, receiver) = crossbeam_channel::bounded(10);
+    fn new() -> (Self, MainLoopCancellationToken) {
+        let (orchestrator_sender, orchestrator_receiver) = crossbeam_channel::bounded(1);
+        let (main_loop_sender, main_loop_receiver) = crossbeam_channel::bounded(1);
+
+        let mut orchestrator = Orchestrator {
+            pending_analysis: None,
+            receiver: orchestrator_receiver,
+            sender: main_loop_sender.clone(),
+            aggregated_changes: AggregatedChanges::default(),
+        };
+
+        std::thread::spawn(move || {
+            orchestrator.run();
+        });
 
         (
             Self {
-                sender: sender.clone(),
-                receiver,
-                watcher: None,
-                cli_configuration,
+                orchestrator_sender,
+                main_loop_receiver,
+            },
+            MainLoopCancellationToken {
+                sender: main_loop_sender,
             },
-            MainLoopCancellationToken { sender },
         )
     }
 
-    fn watch(mut self, db: &mut RootDatabase) -> anyhow::Result<ExitStatus> {
-        tracing::debug!("Starting watch mode");
-        let sender = self.sender.clone();
-        let watcher = watch::directory_watcher(move |event| {
-            sender.send(MainLoopMessage::ApplyChanges(event)).unwrap();
-        })?;
-
-        self.watcher = Some(WorkspaceWatcher::new(watcher, db));
-
-        self.run(db);
-
-        Ok(ExitStatus::Success)
+    fn file_changes_notifier(&self) -> FileChangesNotifier {
+        FileChangesNotifier {
+            sender: self.orchestrator_sender.clone(),
+        }
     }
 
-    fn run(mut self, db: &mut RootDatabase) -> ExitStatus {
-        self.sender.send(MainLoopMessage::CheckWorkspace).unwrap();
+    fn run(self, program: &mut Program) {
+        self.orchestrator_sender
+            .send(OrchestratorMessage::Run)
+            .unwrap();
 
-        let result = self.main_loop(db);
+        for message in &self.main_loop_receiver {
+            tracing::trace!("Main Loop: Tick");
 
-        tracing::debug!("Exiting main loop");
-
-        result
-    }
-
-    fn main_loop(&mut self, db: &mut RootDatabase) -> ExitStatus {
-        // Schedule the first check.
-        tracing::debug!("Starting main loop");
-
-        let mut revision = 0u64;
-
-        while let Ok(message) = self.receiver.recv() {
             match message {
-                MainLoopMessage::CheckWorkspace => {
-                    let db = db.snapshot();
-                    let sender = self.sender.clone();
+                MainLoopMessage::CheckProgram => {
+                    // Remove mutability from program.
+                    let program = &*program;
+                    let run_cancellation_token_source = CancellationTokenSource::new();
+                    let run_cancellation_token = run_cancellation_token_source.token();
+                    let sender = &self.orchestrator_sender;
 
-                    // Spawn a new task that checks the workspace. This needs to be done in a separate thread
-                    // to prevent blocking the main loop here.
-                    rayon::spawn(move || {
-                        if let Ok(result) = db.check() {
-                            // Send the result back to the main loop for printing.
-                            sender
-                                .send(MainLoopMessage::CheckCompleted { result, revision })
-                                .unwrap();
+                    sender
+                        .send(OrchestratorMessage::CheckProgramStarted {
+                            cancellation_token: run_cancellation_token_source,
+                        })
+                        .unwrap();
+
+                    rayon::in_place_scope(|scope| {
+                        let scheduler = RayonCheckScheduler::new(program, scope);
+
+                        let result = program.check(&scheduler, run_cancellation_token);
+                        match result {
+                            Ok(result) => sender
+                                .send(OrchestratorMessage::CheckProgramCompleted(result))
+                                .unwrap(),
+                            Err(CheckError::Cancelled) => sender
+                                .send(OrchestratorMessage::CheckProgramCancelled)
+                                .unwrap(),
                         }
                     });
                 }
-
-                MainLoopMessage::CheckCompleted {
-                    result,
-                    revision: check_revision,
-                } => {
-                    let has_diagnostics = !result.is_empty();
-                    if check_revision == revision {
-                        #[allow(clippy::print_stdout)]
-                        for diagnostic in result {
-                            println!("{}", diagnostic.display(db));
-                        }
-                    } else {
-                        tracing::debug!(
-                            "Discarding check result for outdated revision: current: {revision}, result revision: {check_revision}"
-                        );
-                    }
-
-                    if self.watcher.is_none() {
-                        return if has_diagnostics {
-                            ExitStatus::Failure
-                        } else {
-                            ExitStatus::Success
-                        };
-                    }
-
-                    tracing::trace!("Counts after last check:\n{}", countme::get_all());
-                }
-
                 MainLoopMessage::ApplyChanges(changes) => {
-                    revision += 1;
-                    // Automatically cancels any pending queries and waits for them to complete.
-                    db.apply_changes(changes, Some(&self.cli_configuration));
-                    if let Some(watcher) = self.watcher.as_mut() {
-                        watcher.update(db);
-                    }
-                    self.sender.send(MainLoopMessage::CheckWorkspace).unwrap();
+                    program.apply_changes(changes.iter());
+                }
+                MainLoopMessage::CheckCompleted(diagnostics) => {
+                    dbg!(diagnostics);
                 }
                 MainLoopMessage::Exit => {
-                    // Cancel any pending queries and wait for them to complete.
-                    // TODO: Don't use Salsa internal APIs
-                    //  [Zulip-Thread](https://salsa.zulipchat.com/#narrow/stream/333573-salsa-3.2E0/topic/Expose.20an.20API.20to.20cancel.20other.20queries)
-                    let _ = db.zalsa_mut();
-                    return ExitStatus::Success;
+                    return;
                 }
             }
-
-            tracing::debug!("Waiting for next main loop message.");
         }
+    }
+}
 
-        ExitStatus::Success
+impl Drop for MainLoop {
+    fn drop(&mut self) {
+        self.orchestrator_sender
+            .send(OrchestratorMessage::Shutdown)
+            .unwrap();
+    }
+}
+
+#[derive(Debug, Clone)]
+struct FileChangesNotifier {
+    sender: crossbeam_channel::Sender<OrchestratorMessage>,
+}
+
+impl FileChangesNotifier {
+    fn notify(&self, changes: Vec<FileChange>) {
+        self.sender
+            .send(OrchestratorMessage::FileChanges(changes))
+            .unwrap();
     }
 }
 
@@ -375,14 +210,260 @@ impl MainLoopCancellationToken {
     }
 }
 
+struct Orchestrator {
+    aggregated_changes: AggregatedChanges,
+    pending_analysis: Option<PendingAnalysisState>,
+
+    /// Sends messages to the main loop.
+    sender: crossbeam_channel::Sender<MainLoopMessage>,
+    /// Receives messages from the main loop.
+    receiver: crossbeam_channel::Receiver<OrchestratorMessage>,
+}
+
+impl Orchestrator {
+    fn run(&mut self) {
+        while let Ok(message) = self.receiver.recv() {
+            match message {
+                OrchestratorMessage::Run => {
+                    self.pending_analysis = None;
+                    self.sender.send(MainLoopMessage::CheckProgram).unwrap();
+                }
+
+                OrchestratorMessage::CheckProgramStarted { cancellation_token } => {
+                    debug_assert!(self.pending_analysis.is_none());
+
+                    self.pending_analysis = Some(PendingAnalysisState { cancellation_token });
+                }
+
+                OrchestratorMessage::CheckProgramCompleted(diagnostics) => {
+                    self.pending_analysis
+                        .take()
+                        .expect("Expected a pending analysis.");
+
+                    self.sender
+                        .send(MainLoopMessage::CheckCompleted(diagnostics))
+                        .unwrap();
+                }
+
+                OrchestratorMessage::CheckProgramCancelled => {
+                    self.pending_analysis
+                        .take()
+                        .expect("Expected a pending analysis.");
+
+                    self.debounce_changes();
+                }
+
+                OrchestratorMessage::FileChanges(changes) => {
+                    // Request cancellation, but wait until all analysis tasks have completed to
+                    // avoid stale messages in the next main loop.
+                    let pending = if let Some(pending_state) = self.pending_analysis.as_ref() {
+                        pending_state.cancellation_token.cancel();
+                        true
+                    } else {
+                        false
+                    };
+
+                    self.aggregated_changes.extend(changes);
+
+                    // If there are no pending analysis tasks, apply the file changes. Otherwise
+                    // keep running until all file checks have completed.
+                    if !pending {
+                        self.debounce_changes();
+                    }
+                }
+                OrchestratorMessage::Shutdown => {
+                    return self.shutdown();
+                }
+            }
+        }
+    }
+
+    fn debounce_changes(&mut self) {
+        debug_assert!(self.pending_analysis.is_none());
+
+        loop {
+            // Consume possibly incoming file change messages before running a new analysis, but don't wait for more than 100ms.
+            crossbeam_channel::select! {
+                recv(self.receiver) -> message => {
+                    match message {
+                        Ok(OrchestratorMessage::Shutdown) => {
+                            return self.shutdown();
+                        }
+                        Ok(OrchestratorMessage::FileChanges(file_changes)) => {
+                            self.aggregated_changes.extend(file_changes);
+                        }
+
+                        Ok(OrchestratorMessage::CheckProgramStarted {..}| OrchestratorMessage::CheckProgramCompleted(_) | OrchestratorMessage::CheckProgramCancelled) => unreachable!("No program check should be running while debouncing changes."),
+                        Ok(OrchestratorMessage::Run) => unreachable!("The orchestrator is already running."),
+
+                        Err(_) => {
+                            // There are no more senders, no point in waiting for more messages
+                            return;
+                        }
+                    }
+                },
+                default(std::time::Duration::from_millis(100)) => {
+                    // No more file changes after 100 ms, send the changes and schedule a new analysis
+                    self.sender.send(MainLoopMessage::ApplyChanges(std::mem::take(&mut self.aggregated_changes))).unwrap();
+                    self.sender.send(MainLoopMessage::CheckProgram).unwrap();
+                    return;
+                }
+            }
+        }
+    }
+
+    #[allow(clippy::unused_self)]
+    fn shutdown(&self) {
+        tracing::trace!("Shutting down orchestrator.");
+    }
+}
+
+#[derive(Debug)]
+struct PendingAnalysisState {
+    cancellation_token: CancellationTokenSource,
+}
+
 /// Message sent from the orchestrator to the main loop.
 #[derive(Debug)]
 enum MainLoopMessage {
-    CheckWorkspace,
-    CheckCompleted {
-        result: Vec<Box<dyn Diagnostic>>,
-        revision: u64,
-    },
-    ApplyChanges(Vec<watch::ChangeEvent>),
+    CheckProgram,
+    CheckCompleted(Vec<String>),
+    ApplyChanges(AggregatedChanges),
     Exit,
 }
+
+#[derive(Debug)]
+enum OrchestratorMessage {
+    Run,
+    Shutdown,
+
+    CheckProgramStarted {
+        cancellation_token: CancellationTokenSource,
+    },
+    CheckProgramCompleted(Vec<String>),
+    CheckProgramCancelled,
+
+    FileChanges(Vec<FileChange>),
+}
+
+#[derive(Default, Debug)]
+struct AggregatedChanges {
+    changes: FxHashMap<FileId, FileChangeKind>,
+}
+
+impl AggregatedChanges {
+    fn add(&mut self, change: FileChange) {
+        match self.changes.entry(change.file_id()) {
+            Entry::Occupied(mut entry) => {
+                let merged = entry.get_mut();
+
+                match (merged, change.kind()) {
+                    (FileChangeKind::Created, FileChangeKind::Deleted) => {
+                        // Deletion after creations means that ruff never saw the file.
+                        entry.remove();
+                    }
+                    (FileChangeKind::Created, FileChangeKind::Modified) => {
+                        // No-op, for ruff, modifying a file that it doesn't yet know that it exists is still considered a creation.
+                    }
+
+                    (FileChangeKind::Modified, FileChangeKind::Created) => {
+                        // Uhh, that should probably not happen. Continue considering it a modification.
+                    }
+
+                    (FileChangeKind::Modified, FileChangeKind::Deleted) => {
+                        *entry.get_mut() = FileChangeKind::Deleted;
+                    }
+
+                    (FileChangeKind::Deleted, FileChangeKind::Created) => {
+                        *entry.get_mut() = FileChangeKind::Modified;
+                    }
+
+                    (FileChangeKind::Deleted, FileChangeKind::Modified) => {
+                        // That's weird, but let's consider it a modification.
+                        *entry.get_mut() = FileChangeKind::Modified;
+                    }
+
+                    (FileChangeKind::Created, FileChangeKind::Created)
+                    | (FileChangeKind::Modified, FileChangeKind::Modified)
+                    | (FileChangeKind::Deleted, FileChangeKind::Deleted) => {
+                        // No-op transitions. Some of them should be impossible but we handle them anyway.
+                    }
+                }
+            }
+            Entry::Vacant(entry) => {
+                entry.insert(change.kind());
+            }
+        }
+    }
+
+    fn extend<I>(&mut self, changes: I)
+    where
+        I: IntoIterator<Item = FileChange>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let iter = changes.into_iter();
+        self.changes.reserve(iter.len());
+
+        for change in iter {
+            self.add(change);
+        }
+    }
+
+    fn iter(&self) -> impl Iterator<Item = FileChange> + '_ {
+        self.changes
+            .iter()
+            .map(|(id, kind)| FileChange::new(*id, *kind))
+    }
+}
+
+fn setup_tracing() {
+    let subscriber = Registry::default().with(
+        tracing_tree::HierarchicalLayer::default()
+            .with_indent_lines(true)
+            .with_indent_amount(2)
+            .with_bracketed_fields(true)
+            .with_thread_ids(true)
+            .with_targets(true)
+            .with_writer(|| Box::new(std::io::stderr()))
+            .with_timer(Uptime::default())
+            .with_filter(LoggingFilter {
+                trace_level: Level::TRACE,
+            }),
+    );
+
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+}
+
+struct LoggingFilter {
+    trace_level: Level,
+}
+
+impl LoggingFilter {
+    fn is_enabled(&self, meta: &Metadata<'_>) -> bool {
+        let filter = if meta.target().starts_with("red_knot") || meta.target().starts_with("ruff") {
+            self.trace_level
+        } else {
+            Level::INFO
+        };
+
+        meta.level() <= &filter
+    }
+}
+
+impl<S> Filter<S> for LoggingFilter {
+    fn enabled(&self, meta: &Metadata<'_>, _cx: &Context<'_, S>) -> bool {
+        self.is_enabled(meta)
+    }
+
+    fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest {
+        if self.is_enabled(meta) {
+            Interest::always()
+        } else {
+            Interest::never()
+        }
+    }
+
+    fn max_level_hint(&self) -> Option<LevelFilter> {
+        Some(LevelFilter::from_level(self.trace_level))
+    }
+}

crates/red_knot/src/parse.rs

@@ -0,0 +1,95 @@
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use ruff_python_ast as ast;
+use ruff_python_parser::{Mode, ParseError};
+use ruff_text_size::{Ranged, TextRange};
+
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SourceDb, SourceJar};
+use crate::files::FileId;
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Parsed {
+    inner: Arc<ParsedInner>,
+}
+
+#[derive(Debug, PartialEq)]
+struct ParsedInner {
+    ast: ast::ModModule,
+    errors: Vec<ParseError>,
+}
+
+impl Parsed {
+    fn new(ast: ast::ModModule, errors: Vec<ParseError>) -> Self {
+        Self {
+            inner: Arc::new(ParsedInner { ast, errors }),
+        }
+    }
+
+    pub(crate) fn from_text(text: &str) -> Self {
+        let result = ruff_python_parser::parse(text, Mode::Module);
+
+        let (module, errors) = match result {
+            Ok(ast::Mod::Module(module)) => (module, vec![]),
+            Ok(ast::Mod::Expression(expression)) => (
+                ast::ModModule {
+                    range: expression.range(),
+                    body: vec![ast::Stmt::Expr(ast::StmtExpr {
+                        range: expression.range(),
+                        value: expression.body,
+                    })],
+                },
+                vec![],
+            ),
+            Err(errors) => (
+                ast::ModModule {
+                    range: TextRange::default(),
+                    body: Vec::new(),
+                },
+                vec![errors],
+            ),
+        };
+
+        Parsed::new(module, errors)
+    }
+
+    pub fn ast(&self) -> &ast::ModModule {
+        &self.inner.ast
+    }
+
+    pub fn errors(&self) -> &[ParseError] {
+        &self.inner.errors
+    }
+}
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn parse<Db>(db: &Db, file_id: FileId) -> Parsed
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let parsed = db.jar();
+
+    parsed.parsed.get(&file_id, |file_id| {
+        let source = db.source(*file_id);
+
+        Parsed::from_text(source.text())
+    })
+}
+
+#[derive(Debug, Default)]
+pub struct ParsedStorage(KeyValueCache<FileId, Parsed>);
+
+impl Deref for ParsedStorage {
+    type Target = KeyValueCache<FileId, Parsed>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for ParsedStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/program/check.rs

@@ -0,0 +1,306 @@
+use crate::cancellation::CancellationToken;
+use crate::db::{SemanticDb, SourceDb};
+use crate::files::FileId;
+use crate::lint::Diagnostics;
+use crate::program::Program;
+use rayon::max_num_threads;
+use rustc_hash::FxHashSet;
+use std::num::NonZeroUsize;
+
+impl Program {
+    /// Checks all open files in the workspace and its dependencies.
+    #[tracing::instrument(level = "debug", skip_all)]
+    pub fn check(
+        &self,
+        scheduler: &dyn CheckScheduler,
+        cancellation_token: CancellationToken,
+    ) -> Result<Vec<String>, CheckError> {
+        let check_loop = CheckFilesLoop::new(scheduler, cancellation_token);
+
+        check_loop.run(self.workspace().open_files.iter().copied())
+    }
+
+    /// Checks a single file and its dependencies.
+    #[tracing::instrument(level = "debug", skip(self, scheduler, cancellation_token))]
+    pub fn check_file(
+        &self,
+        file: FileId,
+        scheduler: &dyn CheckScheduler,
+        cancellation_token: CancellationToken,
+    ) -> Result<Vec<String>, CheckError> {
+        let check_loop = CheckFilesLoop::new(scheduler, cancellation_token);
+
+        check_loop.run([file].into_iter())
+    }
+
+    #[tracing::instrument(level = "debug", skip(self, context))]
+    fn do_check_file(
+        &self,
+        file: FileId,
+        context: &CheckContext,
+    ) -> Result<Diagnostics, CheckError> {
+        context.cancelled_ok()?;
+
+        let symbol_table = self.symbol_table(file);
+        let dependencies = symbol_table.dependencies();
+
+        if !dependencies.is_empty() {
+            let module = self.file_to_module(file);
+
+            // TODO scheduling all dependencies here is wasteful if we don't infer any types on them
+            //  but I think that's unlikely, so it is okay?
+            //  Anyway, we need to figure out a way to retrieve the dependencies of a module
+            //  from the persistent cache. So maybe it should be a separate query after all.
+            for dependency in dependencies {
+                let dependency_name = dependency.module_name(self, module);
+
+                if let Some(dependency_name) = dependency_name {
+                    // TODO We may want to have a different check functions for non-first-party
+                    //   files because we only need to index them and not check them.
+                    //   Supporting non-first-party code also requires supporting typing stubs.
+                    if let Some(dependency) = self.resolve_module(dependency_name) {
+                        if dependency.path(self).root().kind().is_first_party() {
+                            context.schedule_check_file(dependency.path(self).file());
+                        }
+                    }
+                }
+            }
+        }
+
+        let mut diagnostics = Vec::new();
+
+        if self.workspace().is_file_open(file) {
+            diagnostics.extend_from_slice(&self.lint_syntax(file));
+        }
+
+        Ok(Diagnostics::from(diagnostics))
+    }
+}
+
+/// Schedules checks for files.
+pub trait CheckScheduler {
+    /// Schedules a check for a file.
+    ///
+    /// The check can either be run immediately on the current thread or the check can be queued
+    /// in a thread pool and ran asynchronously.
+    ///
+    /// The order in which scheduled checks are executed is not guaranteed.
+    ///
+    /// The implementation should call [`CheckFileTask::run`] to execute the check.
+    fn check_file(&self, file_task: CheckFileTask);
+
+    /// The maximum number of checks that can be run concurrently.
+    ///
+    /// Returns `None` if the checks run on the current thread (no concurrency).
+    fn max_concurrency(&self) -> Option<NonZeroUsize>;
+}
+
+/// Scheduler that runs checks on a rayon thread pool.
+pub struct RayonCheckScheduler<'program, 'scope_ref, 'scope> {
+    program: &'program Program,
+    scope: &'scope_ref rayon::Scope<'scope>,
+}
+
+impl<'program, 'scope_ref, 'scope> RayonCheckScheduler<'program, 'scope_ref, 'scope> {
+    pub fn new(program: &'program Program, scope: &'scope_ref rayon::Scope<'scope>) -> Self {
+        Self { program, scope }
+    }
+}
+
+impl<'program, 'scope_ref, 'scope> CheckScheduler
+    for RayonCheckScheduler<'program, 'scope_ref, 'scope>
+where
+    'program: 'scope,
+{
+    fn check_file(&self, check_file_task: CheckFileTask) {
+        let child_span =
+            tracing::trace_span!("check_file", file_id = check_file_task.file_id.as_u32());
+        let program = self.program;
+
+        self.scope
+            .spawn(move |_| child_span.in_scope(|| check_file_task.run(program)));
+    }
+
+    fn max_concurrency(&self) -> Option<NonZeroUsize> {
+        Some(NonZeroUsize::new(max_num_threads()).unwrap_or(NonZeroUsize::MIN))
+    }
+}
+
+/// Scheduler that runs all checks on the current thread.
+pub struct SameThreadCheckScheduler<'a> {
+    program: &'a Program,
+}
+
+impl<'a> SameThreadCheckScheduler<'a> {
+    pub fn new(program: &'a Program) -> Self {
+        Self { program }
+    }
+}
+
+impl CheckScheduler for SameThreadCheckScheduler<'_> {
+    fn check_file(&self, task: CheckFileTask) {
+        task.run(self.program);
+    }
+
+    fn max_concurrency(&self) -> Option<NonZeroUsize> {
+        None
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum CheckError {
+    Cancelled,
+}
+
+#[derive(Debug)]
+pub struct CheckFileTask {
+    file_id: FileId,
+    context: CheckContext,
+}
+
+impl CheckFileTask {
+    /// Runs the check and communicates the result to the orchestrator.
+    pub fn run(self, program: &Program) {
+        match program.do_check_file(self.file_id, &self.context) {
+            Ok(diagnostics) => self
+                .context
+                .sender
+                .send(CheckFileMessage::Completed(diagnostics))
+                .unwrap(),
+            Err(CheckError::Cancelled) => self
+                .context
+                .sender
+                .send(CheckFileMessage::Cancelled)
+                .unwrap(),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct CheckContext {
+    cancellation_token: CancellationToken,
+    sender: crossbeam_channel::Sender<CheckFileMessage>,
+}
+
+impl CheckContext {
+    fn new(
+        cancellation_token: CancellationToken,
+        sender: crossbeam_channel::Sender<CheckFileMessage>,
+    ) -> Self {
+        Self {
+            cancellation_token,
+            sender,
+        }
+    }
+
+    /// Queues a new file for checking using the [`CheckScheduler`].
+    #[allow(unused)]
+    fn schedule_check_file(&self, file_id: FileId) {
+        self.sender.send(CheckFileMessage::Queue(file_id)).unwrap();
+    }
+
+    /// Returns `true` if the check has been cancelled.
+    fn is_cancelled(&self) -> bool {
+        self.cancellation_token.is_cancelled()
+    }
+
+    fn cancelled_ok(&self) -> Result<(), CheckError> {
+        if self.is_cancelled() {
+            Err(CheckError::Cancelled)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+struct CheckFilesLoop<'a> {
+    scheduler: &'a dyn CheckScheduler,
+    cancellation_token: CancellationToken,
+    pending: usize,
+    queued_files: FxHashSet<FileId>,
+}
+
+impl<'a> CheckFilesLoop<'a> {
+    fn new(scheduler: &'a dyn CheckScheduler, cancellation_token: CancellationToken) -> Self {
+        Self {
+            scheduler,
+            cancellation_token,
+
+            queued_files: FxHashSet::default(),
+            pending: 0,
+        }
+    }
+
+    fn run(mut self, files: impl Iterator<Item = FileId>) -> Result<Vec<String>, CheckError> {
+        let (sender, receiver) = if let Some(max_concurrency) = self.scheduler.max_concurrency() {
+            crossbeam_channel::bounded(max_concurrency.get())
+        } else {
+            // The checks run on the current thread. That means it is necessary to store all messages
+            // or we risk deadlocking when the main loop never gets a chance to read the messages.
+            crossbeam_channel::unbounded()
+        };
+
+        let context = CheckContext::new(self.cancellation_token.clone(), sender.clone());
+
+        for file in files {
+            self.queue_file(file, context.clone())?;
+        }
+
+        self.run_impl(receiver, &context)
+    }
+
+    fn run_impl(
+        mut self,
+        receiver: crossbeam_channel::Receiver<CheckFileMessage>,
+        context: &CheckContext,
+    ) -> Result<Vec<String>, CheckError> {
+        if self.cancellation_token.is_cancelled() {
+            return Err(CheckError::Cancelled);
+        }
+
+        let mut result = Vec::default();
+
+        for message in receiver {
+            match message {
+                CheckFileMessage::Completed(diagnostics) => {
+                    result.extend_from_slice(&diagnostics);
+
+                    self.pending -= 1;
+
+                    if self.pending == 0 {
+                        break;
+                    }
+                }
+                CheckFileMessage::Queue(id) => {
+                    self.queue_file(id, context.clone())?;
+                }
+                CheckFileMessage::Cancelled => {
+                    return Err(CheckError::Cancelled);
+                }
+            }
+        }
+
+        Ok(result)
+    }
+
+    fn queue_file(&mut self, file_id: FileId, context: CheckContext) -> Result<(), CheckError> {
+        if context.is_cancelled() {
+            return Err(CheckError::Cancelled);
+        }
+
+        if self.queued_files.insert(file_id) {
+            self.pending += 1;
+
+            self.scheduler
+                .check_file(CheckFileTask { file_id, context });
+        }
+
+        Ok(())
+    }
+}
+
+enum CheckFileMessage {
+    Completed(Diagnostics),
+    Queue(FileId),
+    Cancelled,
+}

crates/red_knot/src/program/mod.rs

@@ -0,0 +1,176 @@
+pub mod check;
+
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::db::{Db, HasJar, SemanticDb, SemanticJar, SourceDb, SourceJar};
+use crate::files::{FileId, Files};
+use crate::lint::{lint_syntax, Diagnostics, LintSyntaxStorage};
+use crate::module::{
+    add_module, file_to_module, path_to_module, resolve_module, set_module_search_paths, Module,
+    ModuleData, ModuleName, ModuleResolver, ModuleSearchPath,
+};
+use crate::parse::{parse, Parsed, ParsedStorage};
+use crate::source::{source_text, Source, SourceStorage};
+use crate::symbols::{symbol_table, SymbolId, SymbolTable, SymbolTablesStorage};
+use crate::types::{infer_symbol_type, Type, TypeStore};
+use crate::Workspace;
+
+#[derive(Debug)]
+pub struct Program {
+    files: Files,
+    source: SourceJar,
+    semantic: SemanticJar,
+    workspace: Workspace,
+}
+
+impl Program {
+    pub fn new(workspace: Workspace, module_search_paths: Vec<ModuleSearchPath>) -> Self {
+        Self {
+            source: SourceJar {
+                sources: SourceStorage::default(),
+                parsed: ParsedStorage::default(),
+                lint_syntax: LintSyntaxStorage::default(),
+            },
+            semantic: SemanticJar {
+                module_resolver: ModuleResolver::new(module_search_paths),
+                symbol_tables: SymbolTablesStorage::default(),
+                type_store: TypeStore::default(),
+            },
+            files: Files::default(),
+            workspace,
+        }
+    }
+
+    pub fn apply_changes<I>(&mut self, changes: I)
+    where
+        I: IntoIterator<Item = FileChange>,
+    {
+        for change in changes {
+            self.semantic
+                .module_resolver
+                .remove_module(&self.file_path(change.id));
+            self.semantic.symbol_tables.remove(&change.id);
+            self.source.sources.remove(&change.id);
+            self.source.parsed.remove(&change.id);
+            self.source.lint_syntax.remove(&change.id);
+            // TODO: remove all dependent modules as well
+            self.semantic.type_store.remove_module(change.id);
+        }
+    }
+
+    pub fn files(&self) -> &Files {
+        &self.files
+    }
+
+    pub fn workspace(&self) -> &Workspace {
+        &self.workspace
+    }
+
+    pub fn workspace_mut(&mut self) -> &mut Workspace {
+        &mut self.workspace
+    }
+}
+
+impl SourceDb for Program {
+    fn file_id(&self, path: &Path) -> FileId {
+        self.files.intern(path)
+    }
+
+    fn file_path(&self, file_id: FileId) -> Arc<Path> {
+        self.files.path(file_id)
+    }
+
+    fn source(&self, file_id: FileId) -> Source {
+        source_text(self, file_id)
+    }
+
+    fn parse(&self, file_id: FileId) -> Parsed {
+        parse(self, file_id)
+    }
+
+    fn lint_syntax(&self, file_id: FileId) -> Diagnostics {
+        lint_syntax(self, file_id)
+    }
+}
+
+impl SemanticDb for Program {
+    fn resolve_module(&self, name: ModuleName) -> Option<Module> {
+        resolve_module(self, name)
+    }
+
+    fn file_to_module(&self, file_id: FileId) -> Option<Module> {
+        file_to_module(self, file_id)
+    }
+
+    fn path_to_module(&self, path: &Path) -> Option<Module> {
+        path_to_module(self, path)
+    }
+
+    fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable> {
+        symbol_table(self, file_id)
+    }
+
+    fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type {
+        infer_symbol_type(self, file_id, symbol_id)
+    }
+
+    // Mutations
+
+    fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)> {
+        add_module(self, path)
+    }
+
+    fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>) {
+        set_module_search_paths(self, paths);
+    }
+}
+
+impl Db for Program {}
+
+impl HasJar<SourceJar> for Program {
+    fn jar(&self) -> &SourceJar {
+        &self.source
+    }
+
+    fn jar_mut(&mut self) -> &mut SourceJar {
+        &mut self.source
+    }
+}
+
+impl HasJar<SemanticJar> for Program {
+    fn jar(&self) -> &SemanticJar {
+        &self.semantic
+    }
+
+    fn jar_mut(&mut self) -> &mut SemanticJar {
+        &mut self.semantic
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct FileChange {
+    id: FileId,
+    kind: FileChangeKind,
+}
+
+impl FileChange {
+    pub fn new(file_id: FileId, kind: FileChangeKind) -> Self {
+        Self { id: file_id, kind }
+    }
+
+    pub fn file_id(&self) -> FileId {
+        self.id
+    }
+
+    pub fn kind(&self) -> FileChangeKind {
+        self.kind
+    }
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum FileChangeKind {
+    Created,
+    Modified,
+    Deleted,
+}

crates/red_knot/src/source.rs

@@ -0,0 +1,96 @@
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SourceDb, SourceJar};
+use ruff_notebook::Notebook;
+use ruff_python_ast::PySourceType;
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use crate::files::FileId;
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn source_text<Db>(db: &Db, file_id: FileId) -> Source
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let sources = &db.jar().sources;
+
+    sources.get(&file_id, |file_id| {
+        let path = db.file_path(*file_id);
+
+        let source_text = std::fs::read_to_string(&path).unwrap_or_else(|err| {
+            tracing::error!("Failed to read file '{path:?}: {err}'. Falling back to empty text");
+            String::new()
+        });
+
+        let python_ty = PySourceType::from(&path);
+
+        let kind = match python_ty {
+            PySourceType::Python => {
+                SourceKind::Python(Arc::from(source_text))
+            }
+            PySourceType::Stub => SourceKind::Stub(Arc::from(source_text)),
+            PySourceType::Ipynb => {
+                let notebook = Notebook::from_source_code(&source_text).unwrap_or_else(|err| {
+                    // TODO should this be changed to never fail?
+                    // or should we instead add a diagnostic somewhere? But what would we return in this case?
+                    tracing::error!(
+                        "Failed to parse notebook '{path:?}: {err}'. Falling back to an empty notebook"
+                    );
+                    Notebook::from_source_code("").unwrap()
+                });
+
+                SourceKind::IpyNotebook(Arc::new(notebook))
+            }
+        };
+
+        Source { kind }
+    })
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum SourceKind {
+    Python(Arc<str>),
+    Stub(Arc<str>),
+    IpyNotebook(Arc<Notebook>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Source {
+    kind: SourceKind,
+}
+
+impl Source {
+    pub fn python<T: Into<Arc<str>>>(source: T) -> Self {
+        Self {
+            kind: SourceKind::Python(source.into()),
+        }
+    }
+    pub fn kind(&self) -> &SourceKind {
+        &self.kind
+    }
+
+    pub fn text(&self) -> &str {
+        match &self.kind {
+            SourceKind::Python(text) => text,
+            SourceKind::Stub(text) => text,
+            SourceKind::IpyNotebook(notebook) => notebook.source_code(),
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct SourceStorage(pub(crate) KeyValueCache<FileId, Source>);
+
+impl Deref for SourceStorage {
+    type Target = KeyValueCache<FileId, Source>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for SourceStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/symbols.rs

@@ -0,0 +1,816 @@
+#![allow(dead_code)]
+
+use std::hash::{Hash, Hasher};
+use std::iter::{Copied, DoubleEndedIterator, FusedIterator};
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use hashbrown::hash_map::{Keys, RawEntryMut};
+use rustc_hash::{FxHashMap, FxHasher};
+
+use ruff_index::{newtype_index, IndexVec};
+use ruff_python_ast as ast;
+use ruff_python_ast::visitor::preorder::PreorderVisitor;
+
+use crate::ast_ids::TypedNodeKey;
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SemanticDb, SemanticJar};
+use crate::files::FileId;
+use crate::module::{Module, ModuleName};
+use crate::Name;
+
+#[allow(unreachable_pub)]
+#[tracing::instrument(level = "debug", skip(db))]
+pub fn symbol_table<Db>(db: &Db, file_id: FileId) -> Arc<SymbolTable>
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    let jar = db.jar();
+
+    jar.symbol_tables.get(&file_id, |_| {
+        let parsed = db.parse(file_id);
+        Arc::from(SymbolTable::from_ast(parsed.ast()))
+    })
+}
+
+type Map<K, V> = hashbrown::HashMap<K, V, ()>;
+
+#[newtype_index]
+pub(crate) struct ScopeId;
+
+impl ScopeId {
+    pub(crate) fn scope(self, table: &SymbolTable) -> &Scope {
+        &table.scopes_by_id[self]
+    }
+}
+
+#[newtype_index]
+pub struct SymbolId;
+
+impl SymbolId {
+    pub(crate) fn symbol(self, table: &SymbolTable) -> &Symbol {
+        &table.symbols_by_id[self]
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub(crate) enum ScopeKind {
+    Module,
+    Annotation,
+    Class,
+    Function,
+}
+
+#[derive(Debug)]
+pub(crate) struct Scope {
+    name: Name,
+    kind: ScopeKind,
+    child_scopes: Vec<ScopeId>,
+    // symbol IDs, hashed by symbol name
+    symbols_by_name: Map<SymbolId, ()>,
+}
+
+impl Scope {
+    pub(crate) fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    pub(crate) fn kind(&self) -> ScopeKind {
+        self.kind
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct Symbol {
+    name: Name,
+}
+
+impl Symbol {
+    pub(crate) fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+// TODO storing TypedNodeKey for definitions means we have to search to find them again in the AST;
+// this is at best O(log n). If looking up definitions is a bottleneck we should look for
+// alternatives here.
+#[derive(Debug)]
+pub(crate) enum Definition {
+    // For the import cases, we don't need reference to any arbitrary AST subtrees (annotations,
+    // RHS), and referencing just the import statement node is imprecise (a single import statement
+    // can assign many symbols, we'd have to re-search for the one we care about), so we just copy
+    // the small amount of information we need from the AST.
+    Import(ImportDefinition),
+    ImportFrom(ImportFromDefinition),
+    ClassDef(TypedNodeKey<ast::StmtClassDef>),
+    FunctionDef(TypedNodeKey<ast::StmtFunctionDef>),
+    Assignment(TypedNodeKey<ast::StmtAssign>),
+    AnnotatedAssignment(TypedNodeKey<ast::StmtAnnAssign>),
+    // TODO with statements, except handlers, function args...
+}
+
+#[derive(Debug)]
+pub(crate) struct ImportDefinition {
+    pub(crate) module: Name,
+}
+
+#[derive(Debug)]
+pub(crate) struct ImportFromDefinition {
+    pub(crate) module: Option<Name>,
+    pub(crate) name: Name,
+    pub(crate) level: u32,
+}
+
+#[derive(Debug, Clone)]
+pub(crate) enum Dependency {
+    Module(Name),
+    Relative { level: u32, module: Option<Name> },
+}
+
+impl Dependency {
+    pub(crate) fn module_name<Db>(&self, db: &Db, relative_to: Option<Module>) -> Option<ModuleName>
+    where
+        Db: SemanticDb + HasJar<SemanticJar>,
+    {
+        match self {
+            Dependency::Module(name) => Some(ModuleName::new(name.as_str())),
+            Dependency::Relative { level, module } => {
+                relative_to?.relative_name(db, *level, module.as_deref())
+            }
+        }
+    }
+}
+
+/// Table of all symbols in all scopes for a module.
+#[derive(Debug)]
+pub struct SymbolTable {
+    scopes_by_id: IndexVec<ScopeId, Scope>,
+    symbols_by_id: IndexVec<SymbolId, Symbol>,
+    defs: FxHashMap<SymbolId, Vec<Definition>>,
+    dependencies: Vec<Dependency>,
+}
+
+impl SymbolTable {
+    pub(crate) fn from_ast(module: &ast::ModModule) -> Self {
+        let root_scope_id = SymbolTable::root_scope_id();
+        let mut builder = SymbolTableBuilder {
+            table: SymbolTable::new(),
+            scopes: vec![root_scope_id],
+        };
+        builder.visit_body(&module.body);
+        builder.table
+    }
+
+    pub(crate) fn new() -> Self {
+        let mut table = SymbolTable {
+            scopes_by_id: IndexVec::new(),
+            symbols_by_id: IndexVec::new(),
+            defs: FxHashMap::default(),
+            dependencies: Vec::new(),
+        };
+        table.scopes_by_id.push(Scope {
+            name: Name::new("<module>"),
+            kind: ScopeKind::Module,
+            child_scopes: Vec::new(),
+            symbols_by_name: Map::default(),
+        });
+        table
+    }
+
+    pub(crate) fn dependencies(&self) -> &[Dependency] {
+        &self.dependencies
+    }
+
+    pub(crate) const fn root_scope_id() -> ScopeId {
+        ScopeId::from_usize(0)
+    }
+
+    pub(crate) fn root_scope(&self) -> &Scope {
+        &self.scopes_by_id[SymbolTable::root_scope_id()]
+    }
+
+    pub(crate) fn symbol_ids_for_scope(&self, scope_id: ScopeId) -> Copied<Keys<SymbolId, ()>> {
+        self.scopes_by_id[scope_id].symbols_by_name.keys().copied()
+    }
+
+    pub(crate) fn symbols_for_scope(
+        &self,
+        scope_id: ScopeId,
+    ) -> SymbolIterator<Copied<Keys<SymbolId, ()>>> {
+        SymbolIterator {
+            table: self,
+            ids: self.symbol_ids_for_scope(scope_id),
+        }
+    }
+
+    pub(crate) fn root_symbol_ids(&self) -> Copied<Keys<SymbolId, ()>> {
+        self.symbol_ids_for_scope(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn root_symbols(&self) -> SymbolIterator<Copied<Keys<SymbolId, ()>>> {
+        self.symbols_for_scope(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn child_scope_ids_of(&self, scope_id: ScopeId) -> &[ScopeId] {
+        &self.scopes_by_id[scope_id].child_scopes
+    }
+
+    pub(crate) fn child_scopes_of(&self, scope_id: ScopeId) -> ScopeIterator<&[ScopeId]> {
+        ScopeIterator {
+            table: self,
+            ids: self.child_scope_ids_of(scope_id),
+        }
+    }
+
+    pub(crate) fn root_child_scope_ids(&self) -> &[ScopeId] {
+        self.child_scope_ids_of(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn root_child_scopes(&self) -> ScopeIterator<&[ScopeId]> {
+        self.child_scopes_of(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn symbol_id_by_name(&self, scope_id: ScopeId, name: &str) -> Option<SymbolId> {
+        let scope = &self.scopes_by_id[scope_id];
+        let hash = SymbolTable::hash_name(name);
+        let name = Name::new(name);
+        scope
+            .symbols_by_name
+            .raw_entry()
+            .from_hash(hash, |symid| self.symbols_by_id[*symid].name == name)
+            .map(|(symbol_id, ())| *symbol_id)
+    }
+
+    pub(crate) fn symbol_by_name(&self, scope_id: ScopeId, name: &str) -> Option<&Symbol> {
+        Some(&self.symbols_by_id[self.symbol_id_by_name(scope_id, name)?])
+    }
+
+    pub(crate) fn root_symbol_id_by_name(&self, name: &str) -> Option<SymbolId> {
+        self.symbol_id_by_name(SymbolTable::root_scope_id(), name)
+    }
+
+    pub(crate) fn root_symbol_by_name(&self, name: &str) -> Option<&Symbol> {
+        self.symbol_by_name(SymbolTable::root_scope_id(), name)
+    }
+
+    pub(crate) fn defs(&self, symbol_id: SymbolId) -> &[Definition] {
+        self.defs
+            .get(&symbol_id)
+            .map(std::vec::Vec::as_slice)
+            .unwrap_or_default()
+    }
+
+    fn add_symbol_to_scope(&mut self, scope_id: ScopeId, name: &str) -> SymbolId {
+        let hash = SymbolTable::hash_name(name);
+        let scope = &mut self.scopes_by_id[scope_id];
+        let name = Name::new(name);
+
+        let entry = scope
+            .symbols_by_name
+            .raw_entry_mut()
+            .from_hash(hash, |existing| self.symbols_by_id[*existing].name == name);
+
+        match entry {
+            RawEntryMut::Occupied(entry) => *entry.key(),
+            RawEntryMut::Vacant(entry) => {
+                let id = self.symbols_by_id.push(Symbol { name });
+                entry.insert_with_hasher(hash, id, (), |_| hash);
+                id
+            }
+        }
+    }
+
+    fn add_child_scope(
+        &mut self,
+        parent_scope_id: ScopeId,
+        name: &str,
+        kind: ScopeKind,
+    ) -> ScopeId {
+        let new_scope_id = self.scopes_by_id.push(Scope {
+            name: Name::new(name),
+            kind,
+            child_scopes: Vec::new(),
+            symbols_by_name: Map::default(),
+        });
+        let parent_scope = &mut self.scopes_by_id[parent_scope_id];
+        parent_scope.child_scopes.push(new_scope_id);
+        new_scope_id
+    }
+
+    fn hash_name(name: &str) -> u64 {
+        let mut hasher = FxHasher::default();
+        name.hash(&mut hasher);
+        hasher.finish()
+    }
+}
+
+pub(crate) struct SymbolIterator<'a, I> {
+    table: &'a SymbolTable,
+    ids: I,
+}
+
+impl<'a, I> Iterator for SymbolIterator<'a, I>
+where
+    I: Iterator<Item = SymbolId>,
+{
+    type Item = &'a Symbol;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next()?;
+        Some(&self.table.symbols_by_id[id])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.ids.size_hint()
+    }
+}
+
+impl<'a, I> FusedIterator for SymbolIterator<'a, I> where
+    I: Iterator<Item = SymbolId> + FusedIterator
+{
+}
+
+impl<'a, I> DoubleEndedIterator for SymbolIterator<'a, I>
+where
+    I: Iterator<Item = SymbolId> + DoubleEndedIterator,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next_back()?;
+        Some(&self.table.symbols_by_id[id])
+    }
+}
+
+pub(crate) struct ScopeIterator<'a, I> {
+    table: &'a SymbolTable,
+    ids: I,
+}
+
+impl<'a, I> Iterator for ScopeIterator<'a, I>
+where
+    I: Iterator<Item = ScopeId>,
+{
+    type Item = &'a Scope;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next()?;
+        Some(&self.table.scopes_by_id[id])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.ids.size_hint()
+    }
+}
+
+impl<'a, I> FusedIterator for ScopeIterator<'a, I> where I: Iterator<Item = ScopeId> + FusedIterator {}
+
+impl<'a, I> DoubleEndedIterator for ScopeIterator<'a, I>
+where
+    I: Iterator<Item = ScopeId> + DoubleEndedIterator,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next_back()?;
+        Some(&self.table.scopes_by_id[id])
+    }
+}
+
+struct SymbolTableBuilder {
+    table: SymbolTable,
+    scopes: Vec<ScopeId>,
+}
+
+impl SymbolTableBuilder {
+    fn add_symbol(&mut self, identifier: &str) -> SymbolId {
+        self.table.add_symbol_to_scope(self.cur_scope(), identifier)
+    }
+
+    fn add_symbol_with_def(&mut self, identifier: &str, definition: Definition) -> SymbolId {
+        let symbol_id = self.add_symbol(identifier);
+        self.table
+            .defs
+            .entry(symbol_id)
+            .or_default()
+            .push(definition);
+        symbol_id
+    }
+
+    fn push_scope(&mut self, child_of: ScopeId, name: &str, kind: ScopeKind) -> ScopeId {
+        let scope_id = self.table.add_child_scope(child_of, name, kind);
+        self.scopes.push(scope_id);
+        scope_id
+    }
+
+    fn pop_scope(&mut self) -> ScopeId {
+        self.scopes
+            .pop()
+            .expect("Scope stack should never be empty")
+    }
+
+    fn cur_scope(&self) -> ScopeId {
+        *self
+            .scopes
+            .last()
+            .expect("Scope stack should never be empty")
+    }
+
+    fn with_type_params(
+        &mut self,
+        name: &str,
+        params: &Option<Box<ast::TypeParams>>,
+        nested: impl FnOnce(&mut Self),
+    ) {
+        if let Some(type_params) = params {
+            self.push_scope(self.cur_scope(), name, ScopeKind::Annotation);
+            for type_param in &type_params.type_params {
+                let name = match type_param {
+                    ast::TypeParam::TypeVar(ast::TypeParamTypeVar { name, .. }) => name,
+                    ast::TypeParam::ParamSpec(ast::TypeParamParamSpec { name, .. }) => name,
+                    ast::TypeParam::TypeVarTuple(ast::TypeParamTypeVarTuple { name, .. }) => name,
+                };
+                self.add_symbol(name);
+            }
+        }
+        nested(self);
+        if params.is_some() {
+            self.pop_scope();
+        }
+    }
+}
+
+impl PreorderVisitor<'_> for SymbolTableBuilder {
+    fn visit_expr(&mut self, expr: &ast::Expr) {
+        if let ast::Expr::Name(ast::ExprName { id, .. }) = expr {
+            self.add_symbol(id);
+        }
+        ast::visitor::preorder::walk_expr(self, expr);
+    }
+
+    fn visit_stmt(&mut self, stmt: &ast::Stmt) {
+        // TODO need to capture more definition statements here
+        match stmt {
+            ast::Stmt::ClassDef(node) => {
+                let def = Definition::ClassDef(TypedNodeKey::from_node(node));
+                self.add_symbol_with_def(&node.name, def);
+                self.with_type_params(&node.name, &node.type_params, |builder| {
+                    builder.push_scope(builder.cur_scope(), &node.name, ScopeKind::Class);
+                    ast::visitor::preorder::walk_stmt(builder, stmt);
+                    builder.pop_scope();
+                });
+            }
+            ast::Stmt::FunctionDef(node) => {
+                let def = Definition::FunctionDef(TypedNodeKey::from_node(node));
+                self.add_symbol_with_def(&node.name, def);
+                self.with_type_params(&node.name, &node.type_params, |builder| {
+                    builder.push_scope(builder.cur_scope(), &node.name, ScopeKind::Function);
+                    ast::visitor::preorder::walk_stmt(builder, stmt);
+                    builder.pop_scope();
+                });
+            }
+            ast::Stmt::Import(ast::StmtImport { names, .. }) => {
+                for alias in names {
+                    let symbol_name = if let Some(asname) = &alias.asname {
+                        asname.id.as_str()
+                    } else {
+                        alias.name.id.split('.').next().unwrap()
+                    };
+
+                    let module = Name::new(&alias.name.id);
+
+                    let def = Definition::Import(ImportDefinition {
+                        module: module.clone(),
+                    });
+                    self.add_symbol_with_def(symbol_name, def);
+                    self.table.dependencies.push(Dependency::Module(module));
+                }
+            }
+            ast::Stmt::ImportFrom(ast::StmtImportFrom {
+                module,
+                names,
+                level,
+                ..
+            }) => {
+                let module = module.as_ref().map(|m| Name::new(&m.id));
+
+                for alias in names {
+                    let symbol_name = if let Some(asname) = &alias.asname {
+                        asname.id.as_str()
+                    } else {
+                        alias.name.id.as_str()
+                    };
+                    let def = Definition::ImportFrom(ImportFromDefinition {
+                        module: module.clone(),
+                        name: Name::new(&alias.name.id),
+                        level: *level,
+                    });
+                    self.add_symbol_with_def(symbol_name, def);
+                }
+
+                let dependency = if let Some(module) = module {
+                    if *level == 0 {
+                        Dependency::Module(module)
+                    } else {
+                        Dependency::Relative {
+                            level: *level,
+                            module: Some(module),
+                        }
+                    }
+                } else {
+                    Dependency::Relative {
+                        level: *level,
+                        module,
+                    }
+                };
+
+                self.table.dependencies.push(dependency);
+            }
+            _ => {
+                ast::visitor::preorder::walk_stmt(self, stmt);
+            }
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct SymbolTablesStorage(KeyValueCache<FileId, Arc<SymbolTable>>);
+
+impl Deref for SymbolTablesStorage {
+    type Target = KeyValueCache<FileId, Arc<SymbolTable>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for SymbolTablesStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use textwrap::dedent;
+
+    use crate::parse::Parsed;
+    use crate::symbols::ScopeKind;
+
+    use super::{SymbolId, SymbolIterator, SymbolTable};
+
+    mod from_ast {
+        use super::*;
+
+        fn parse(code: &str) -> Parsed {
+            Parsed::from_text(&dedent(code))
+        }
+
+        fn names<I>(it: SymbolIterator<I>) -> Vec<&str>
+        where
+            I: Iterator<Item = SymbolId>,
+        {
+            let mut symbols: Vec<_> = it.map(|sym| sym.name.as_str()).collect();
+            symbols.sort_unstable();
+            symbols
+        }
+
+        #[test]
+        fn empty() {
+            let parsed = parse("");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()).len(), 0);
+        }
+
+        #[test]
+        fn simple() {
+            let parsed = parse("x");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["x"]);
+            assert_eq!(
+                table.defs(table.root_symbol_id_by_name("x").unwrap()).len(),
+                0
+            );
+        }
+
+        #[test]
+        fn annotation_only() {
+            let parsed = parse("x: int");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["int", "x"]);
+            // TODO record definition
+        }
+
+        #[test]
+        fn import() {
+            let parsed = parse("import foo");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+            assert_eq!(
+                table
+                    .defs(table.root_symbol_id_by_name("foo").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn import_sub() {
+            let parsed = parse("import foo.bar");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+        }
+
+        #[test]
+        fn import_as() {
+            let parsed = parse("import foo.bar as baz");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["baz"]);
+        }
+
+        #[test]
+        fn import_from() {
+            let parsed = parse("from bar import foo");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+            assert_eq!(
+                table
+                    .defs(table.root_symbol_id_by_name("foo").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn class_scope() {
+            let parsed = parse(
+                "
+                class C:
+                    x = 1
+                y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["C", "y"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let c_scope = scopes[0].scope(&table);
+            assert_eq!(c_scope.kind(), ScopeKind::Class);
+            assert_eq!(c_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(
+                table.defs(table.root_symbol_id_by_name("C").unwrap()).len(),
+                1
+            );
+        }
+
+        #[test]
+        fn func_scope() {
+            let parsed = parse(
+                "
+                def func():
+                    x = 1
+                y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func", "y"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let func_scope = scopes[0].scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Function);
+            assert_eq!(func_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(
+                table
+                    .defs(table.root_symbol_id_by_name("func").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn dupes() {
+            let parsed = parse(
+                "
+                def func():
+                    x = 1
+                def func():
+                    y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 2);
+            let func_scope_1 = scopes[0].scope(&table);
+            let func_scope_2 = scopes[1].scope(&table);
+            assert_eq!(func_scope_1.kind(), ScopeKind::Function);
+            assert_eq!(func_scope_1.name(), "func");
+            assert_eq!(func_scope_2.kind(), ScopeKind::Function);
+            assert_eq!(func_scope_2.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(names(table.symbols_for_scope(scopes[1])), vec!["y"]);
+            assert_eq!(
+                table
+                    .defs(table.root_symbol_id_by_name("func").unwrap())
+                    .len(),
+                2
+            );
+        }
+
+        #[test]
+        fn generic_func() {
+            let parsed = parse(
+                "
+                def func[T]():
+                    x = 1
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let ann_scope_id = scopes[0];
+            let ann_scope = ann_scope_id.scope(&table);
+            assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
+            assert_eq!(ann_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
+            let scopes = table.child_scope_ids_of(ann_scope_id);
+            assert_eq!(scopes.len(), 1);
+            let func_scope_id = scopes[0];
+            let func_scope = func_scope_id.scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Function);
+            assert_eq!(func_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
+        }
+
+        #[test]
+        fn generic_class() {
+            let parsed = parse(
+                "
+                class C[T]:
+                    x = 1
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["C"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let ann_scope_id = scopes[0];
+            let ann_scope = ann_scope_id.scope(&table);
+            assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
+            assert_eq!(ann_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
+            let scopes = table.child_scope_ids_of(ann_scope_id);
+            assert_eq!(scopes.len(), 1);
+            let func_scope_id = scopes[0];
+            let func_scope = func_scope_id.scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Class);
+            assert_eq!(func_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
+        }
+    }
+
+    #[test]
+    fn insert_same_name_symbol_twice() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let symbol_id_1 = table.add_symbol_to_scope(root_scope_id, "foo");
+        let symbol_id_2 = table.add_symbol_to_scope(root_scope_id, "foo");
+        assert_eq!(symbol_id_1, symbol_id_2);
+    }
+
+    #[test]
+    fn insert_different_named_symbols() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let symbol_id_1 = table.add_symbol_to_scope(root_scope_id, "foo");
+        let symbol_id_2 = table.add_symbol_to_scope(root_scope_id, "bar");
+        assert_ne!(symbol_id_1, symbol_id_2);
+    }
+
+    #[test]
+    fn add_child_scope_with_symbol() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let foo_symbol_top = table.add_symbol_to_scope(root_scope_id, "foo");
+        let c_scope = table.add_child_scope(root_scope_id, "C", ScopeKind::Class);
+        let foo_symbol_inner = table.add_symbol_to_scope(c_scope, "foo");
+        assert_ne!(foo_symbol_top, foo_symbol_inner);
+    }
+
+    #[test]
+    fn scope_from_id() {
+        let table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let scope = root_scope_id.scope(&table);
+        assert_eq!(scope.name.as_str(), "<module>");
+        assert_eq!(scope.kind, ScopeKind::Module);
+    }
+
+    #[test]
+    fn symbol_from_id() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let foo_symbol_id = table.add_symbol_to_scope(root_scope_id, "foo");
+        let symbol = foo_symbol_id.symbol(&table);
+        assert_eq!(symbol.name.as_str(), "foo");
+    }
+}

crates/red_knot/src/target_version.rs

@@ -1,62 +0,0 @@
-/// Enumeration of all supported Python versions
-///
-/// TODO: unify with the `PythonVersion` enum in the linter/formatter crates?
-#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
-pub enum TargetVersion {
-    Py37,
-    Py38,
-    #[default]
-    Py39,
-    Py310,
-    Py311,
-    Py312,
-    Py313,
-}
-
-impl TargetVersion {
-    const fn as_str(self) -> &'static str {
-        match self {
-            Self::Py37 => "py37",
-            Self::Py38 => "py38",
-            Self::Py39 => "py39",
-            Self::Py310 => "py310",
-            Self::Py311 => "py311",
-            Self::Py312 => "py312",
-            Self::Py313 => "py313",
-        }
-    }
-}
-
-impl std::fmt::Display for TargetVersion {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(self.as_str())
-    }
-}
-
-impl From<TargetVersion> for red_knot_python_semantic::PythonVersion {
-    fn from(value: TargetVersion) -> Self {
-        match value {
-            TargetVersion::Py37 => Self::PY37,
-            TargetVersion::Py38 => Self::PY38,
-            TargetVersion::Py39 => Self::PY39,
-            TargetVersion::Py310 => Self::PY310,
-            TargetVersion::Py311 => Self::PY311,
-            TargetVersion::Py312 => Self::PY312,
-            TargetVersion::Py313 => Self::PY313,
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::target_version::TargetVersion;
-    use red_knot_python_semantic::PythonVersion;
-
-    #[test]
-    fn same_default_as_python_version() {
-        assert_eq!(
-            PythonVersion::from(TargetVersion::default()),
-            PythonVersion::default()
-        );
-    }
-}

crates/red_knot/src/types.rs

@@ -0,0 +1,554 @@
+#![allow(dead_code)]
+use crate::ast_ids::NodeKey;
+use crate::files::FileId;
+use crate::module::ModuleName;
+use crate::symbols::SymbolId;
+use crate::{FxDashMap, FxHashSet, FxIndexSet, Name};
+use ruff_index::{newtype_index, IndexVec};
+use rustc_hash::FxHashMap;
+
+pub(crate) mod infer;
+
+pub(crate) use infer::infer_symbol_type;
+
+/// unique ID for a type
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Type {
+    /// the dynamic or gradual type: a statically-unknown set of values
+    Any,
+    /// the empty set of values
+    Never,
+    /// unknown type (no annotation)
+    /// equivalent to Any, or to object in strict mode
+    Unknown,
+    /// name is not bound to any value
+    Unbound,
+    /// a specific function object
+    Function(FunctionTypeId),
+    /// a specific class object
+    Class(ClassTypeId),
+    /// the set of Python objects with the given class in their __class__'s method resolution order
+    Instance(ClassTypeId),
+    Union(UnionTypeId),
+    Intersection(IntersectionTypeId),
+    // TODO protocols, callable types, overloads, generics, type vars
+}
+
+impl Type {
+    fn display<'a>(&'a self, store: &'a TypeStore) -> DisplayType<'a> {
+        DisplayType { ty: self, store }
+    }
+}
+
+// TODO: currently calling `get_function` et al and holding on to the `FunctionTypeRef` will lock a
+// shard of this dashmap, for as long as you hold the reference. This may be a problem. We could
+// switch to having all the arenas hold Arc, or we could see if we can split up ModuleTypeStore,
+// and/or give it inner mutability and finer-grained internal locking.
+#[derive(Debug, Default)]
+pub struct TypeStore {
+    modules: FxDashMap<FileId, ModuleTypeStore>,
+}
+
+impl TypeStore {
+    pub fn remove_module(&self, file_id: FileId) {
+        self.modules.remove(&file_id);
+    }
+
+    pub fn cache_symbol_type(&self, file_id: FileId, symbol_id: SymbolId, ty: Type) {
+        self.add_or_get_module(file_id)
+            .symbol_types
+            .insert(symbol_id, ty);
+    }
+
+    pub fn cache_node_type(&self, file_id: FileId, node_key: NodeKey, ty: Type) {
+        self.add_or_get_module(file_id)
+            .node_types
+            .insert(node_key, ty);
+    }
+
+    pub fn get_cached_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Option<Type> {
+        self.try_get_module(file_id)?
+            .symbol_types
+            .get(&symbol_id)
+            .copied()
+    }
+
+    pub fn get_cached_node_type(&self, file_id: FileId, node_key: &NodeKey) -> Option<Type> {
+        self.try_get_module(file_id)?
+            .node_types
+            .get(node_key)
+            .copied()
+    }
+
+    fn add_or_get_module(&self, file_id: FileId) -> ModuleStoreRefMut {
+        self.modules
+            .entry(file_id)
+            .or_insert_with(|| ModuleTypeStore::new(file_id))
+    }
+
+    fn get_module(&self, file_id: FileId) -> ModuleStoreRef {
+        self.try_get_module(file_id).expect("module should exist")
+    }
+
+    fn try_get_module(&self, file_id: FileId) -> Option<ModuleStoreRef> {
+        self.modules.get(&file_id)
+    }
+
+    fn add_function(&self, file_id: FileId, name: &str) -> FunctionTypeId {
+        self.add_or_get_module(file_id).add_function(name)
+    }
+
+    fn add_class(&self, file_id: FileId, name: &str) -> ClassTypeId {
+        self.add_or_get_module(file_id).add_class(name)
+    }
+
+    fn add_union(&self, file_id: FileId, elems: &[Type]) -> UnionTypeId {
+        self.add_or_get_module(file_id).add_union(elems)
+    }
+
+    fn add_intersection(
+        &self,
+        file_id: FileId,
+        positive: &[Type],
+        negative: &[Type],
+    ) -> IntersectionTypeId {
+        self.add_or_get_module(file_id)
+            .add_intersection(positive, negative)
+    }
+
+    fn get_function(&self, id: FunctionTypeId) -> FunctionTypeRef {
+        FunctionTypeRef {
+            module_store: self.get_module(id.file_id),
+            function_id: id.func_id,
+        }
+    }
+
+    fn get_class(&self, id: ClassTypeId) -> ClassTypeRef {
+        ClassTypeRef {
+            module_store: self.get_module(id.file_id),
+            class_id: id.class_id,
+        }
+    }
+
+    fn get_union(&self, id: UnionTypeId) -> UnionTypeRef {
+        UnionTypeRef {
+            module_store: self.get_module(id.file_id),
+            union_id: id.union_id,
+        }
+    }
+
+    fn get_intersection(&self, id: IntersectionTypeId) -> IntersectionTypeRef {
+        IntersectionTypeRef {
+            module_store: self.get_module(id.file_id),
+            intersection_id: id.intersection_id,
+        }
+    }
+
+    fn record_symbol_dependency(&self, from: (FileId, SymbolId), to: (FileId, SymbolId)) {
+        let (from_file_id, from_symbol_id) = from;
+        self.add_or_get_module(from_file_id)
+            .symbol_dependencies
+            .entry(from_symbol_id)
+            .or_default()
+            .insert(to);
+    }
+
+    fn record_module_dependency(&self, from: (FileId, SymbolId), to: ModuleName) {
+        let (from_file_id, from_symbol_id) = from;
+        self.add_or_get_module(from_file_id)
+            .module_dependencies
+            .entry(from_symbol_id)
+            .or_default()
+            .insert(to);
+    }
+}
+
+type ModuleStoreRef<'a> = dashmap::mapref::one::Ref<
+    'a,
+    FileId,
+    ModuleTypeStore,
+    std::hash::BuildHasherDefault<rustc_hash::FxHasher>,
+>;
+
+type ModuleStoreRefMut<'a> = dashmap::mapref::one::RefMut<
+    'a,
+    FileId,
+    ModuleTypeStore,
+    std::hash::BuildHasherDefault<rustc_hash::FxHasher>,
+>;
+
+#[derive(Debug)]
+pub(crate) struct FunctionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    function_id: ModuleFunctionTypeId,
+}
+
+impl<'a> std::ops::Deref for FunctionTypeRef<'a> {
+    type Target = FunctionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_function(self.function_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct ClassTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    class_id: ModuleClassTypeId,
+}
+
+impl<'a> std::ops::Deref for ClassTypeRef<'a> {
+    type Target = ClassType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_class(self.class_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct UnionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    union_id: ModuleUnionTypeId,
+}
+
+impl<'a> std::ops::Deref for UnionTypeRef<'a> {
+    type Target = UnionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_union(self.union_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct IntersectionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    intersection_id: ModuleIntersectionTypeId,
+}
+
+impl<'a> std::ops::Deref for IntersectionTypeRef<'a> {
+    type Target = IntersectionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_intersection(self.intersection_id)
+    }
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct FunctionTypeId {
+    file_id: FileId,
+    func_id: ModuleFunctionTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct ClassTypeId {
+    file_id: FileId,
+    class_id: ModuleClassTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct UnionTypeId {
+    file_id: FileId,
+    union_id: ModuleUnionTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct IntersectionTypeId {
+    file_id: FileId,
+    intersection_id: ModuleIntersectionTypeId,
+}
+
+#[newtype_index]
+struct ModuleFunctionTypeId;
+
+#[newtype_index]
+struct ModuleClassTypeId;
+
+#[newtype_index]
+struct ModuleUnionTypeId;
+
+#[newtype_index]
+struct ModuleIntersectionTypeId;
+
+#[derive(Debug)]
+struct ModuleTypeStore {
+    file_id: FileId,
+    /// arena of all function types defined in this module
+    functions: IndexVec<ModuleFunctionTypeId, FunctionType>,
+    /// arena of all class types defined in this module
+    classes: IndexVec<ModuleClassTypeId, ClassType>,
+    /// arenda of all union types created in this module
+    unions: IndexVec<ModuleUnionTypeId, UnionType>,
+    /// arena of all intersection types created in this module
+    intersections: IndexVec<ModuleIntersectionTypeId, IntersectionType>,
+    /// cached types of symbols in this module
+    symbol_types: FxHashMap<SymbolId, Type>,
+    /// cached types of AST nodes in this module
+    node_types: FxHashMap<NodeKey, Type>,
+    // the inferred type for symbol K depends on the type of symbols in V
+    symbol_dependencies: FxHashMap<SymbolId, FxHashSet<(FileId, SymbolId)>>,
+    // the inferred type for symbol K depends on the modules in V; this type of dependency is
+    // recorded when e.g. the target symbol doesn't exist in the module, so we can't record a
+    // dependency on a symbol, but if the module changes it could still change our resolution)
+    module_dependencies: FxHashMap<SymbolId, FxHashSet<ModuleName>>,
+}
+
+impl ModuleTypeStore {
+    fn new(file_id: FileId) -> Self {
+        Self {
+            file_id,
+            functions: IndexVec::default(),
+            classes: IndexVec::default(),
+            unions: IndexVec::default(),
+            intersections: IndexVec::default(),
+            symbol_types: FxHashMap::default(),
+            node_types: FxHashMap::default(),
+            symbol_dependencies: FxHashMap::default(),
+            module_dependencies: FxHashMap::default(),
+        }
+    }
+
+    fn add_function(&mut self, name: &str) -> FunctionTypeId {
+        let func_id = self.functions.push(FunctionType {
+            name: Name::new(name),
+        });
+        FunctionTypeId {
+            file_id: self.file_id,
+            func_id,
+        }
+    }
+
+    fn add_class(&mut self, name: &str) -> ClassTypeId {
+        let class_id = self.classes.push(ClassType {
+            name: Name::new(name),
+        });
+        ClassTypeId {
+            file_id: self.file_id,
+            class_id,
+        }
+    }
+
+    fn add_union(&mut self, elems: &[Type]) -> UnionTypeId {
+        let union_id = self.unions.push(UnionType {
+            elements: elems.iter().copied().collect(),
+        });
+        UnionTypeId {
+            file_id: self.file_id,
+            union_id,
+        }
+    }
+
+    fn add_intersection(&mut self, positive: &[Type], negative: &[Type]) -> IntersectionTypeId {
+        let intersection_id = self.intersections.push(IntersectionType {
+            positive: positive.iter().copied().collect(),
+            negative: negative.iter().copied().collect(),
+        });
+        IntersectionTypeId {
+            file_id: self.file_id,
+            intersection_id,
+        }
+    }
+
+    fn get_function(&self, func_id: ModuleFunctionTypeId) -> &FunctionType {
+        &self.functions[func_id]
+    }
+
+    fn get_class(&self, class_id: ModuleClassTypeId) -> &ClassType {
+        &self.classes[class_id]
+    }
+
+    fn get_union(&self, union_id: ModuleUnionTypeId) -> &UnionType {
+        &self.unions[union_id]
+    }
+
+    fn get_intersection(&self, intersection_id: ModuleIntersectionTypeId) -> &IntersectionType {
+        &self.intersections[intersection_id]
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+struct DisplayType<'a> {
+    ty: &'a Type,
+    store: &'a TypeStore,
+}
+
+impl std::fmt::Display for DisplayType<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self.ty {
+            Type::Any => f.write_str("Any"),
+            Type::Never => f.write_str("Never"),
+            Type::Unknown => f.write_str("Unknown"),
+            Type::Unbound => f.write_str("Unbound"),
+            // TODO functions and classes should display using a fully qualified name
+            Type::Class(class_id) => {
+                f.write_str("Literal[")?;
+                f.write_str(self.store.get_class(*class_id).name())?;
+                f.write_str("]")
+            }
+            Type::Instance(class_id) => f.write_str(self.store.get_class(*class_id).name()),
+            Type::Function(func_id) => f.write_str(self.store.get_function(*func_id).name()),
+            Type::Union(union_id) => self
+                .store
+                .get_module(union_id.file_id)
+                .get_union(union_id.union_id)
+                .display(f, self.store),
+            Type::Intersection(int_id) => self
+                .store
+                .get_module(int_id.file_id)
+                .get_intersection(int_id.intersection_id)
+                .display(f, self.store),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct ClassType {
+    name: Name,
+}
+
+impl ClassType {
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct FunctionType {
+    name: Name,
+}
+
+impl FunctionType {
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct UnionType {
+    // the union type includes values in any of these types
+    elements: FxIndexSet<Type>,
+}
+
+impl UnionType {
+    fn display(&self, f: &mut std::fmt::Formatter<'_>, store: &TypeStore) -> std::fmt::Result {
+        f.write_str("(")?;
+        let mut first = true;
+        for ty in &self.elements {
+            if !first {
+                f.write_str(" | ")?;
+            };
+            first = false;
+            write!(f, "{}", ty.display(store))?;
+        }
+        f.write_str(")")
+    }
+}
+
+// Negation types aren't expressible in annotations, and are most likely to arise from type
+// narrowing along with intersections (e.g. `if not isinstance(...)`), so we represent them
+// directly in intersections rather than as a separate type. This sacrifices some efficiency in the
+// case where a Not appears outside an intersection (unclear when that could even happen, but we'd
+// have to represent it as a single-element intersection if it did) in exchange for better
+// efficiency in the not-within-intersection case.
+#[derive(Debug)]
+pub(crate) struct IntersectionType {
+    // the intersection type includes only values in all of these types
+    positive: FxIndexSet<Type>,
+    // negated elements of the intersection, e.g.
+    negative: FxIndexSet<Type>,
+}
+
+impl IntersectionType {
+    fn display(&self, f: &mut std::fmt::Formatter<'_>, store: &TypeStore) -> std::fmt::Result {
+        f.write_str("(")?;
+        let mut first = true;
+        for (neg, ty) in self
+            .positive
+            .iter()
+            .map(|ty| (false, ty))
+            .chain(self.negative.iter().map(|ty| (true, ty)))
+        {
+            if !first {
+                f.write_str(" & ")?;
+            };
+            first = false;
+            if neg {
+                f.write_str("~")?;
+            };
+            write!(f, "{}", ty.display(store))?;
+        }
+        f.write_str(")")
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::files::Files;
+    use crate::types::{Type, TypeStore};
+    use crate::FxIndexSet;
+    use std::path::Path;
+
+    #[test]
+    fn add_class() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let id = store.add_class(file_id, "C");
+        assert_eq!(store.get_class(id).name(), "C");
+        let inst = Type::Instance(id);
+        assert_eq!(format!("{}", inst.display(&store)), "C");
+    }
+
+    #[test]
+    fn add_function() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let id = store.add_function(file_id, "func");
+        assert_eq!(store.get_function(id).name(), "func");
+        let func = Type::Function(id);
+        assert_eq!(format!("{}", func.display(&store)), "func");
+    }
+
+    #[test]
+    fn add_union() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let c1 = store.add_class(file_id, "C1");
+        let c2 = store.add_class(file_id, "C2");
+        let elems = vec![Type::Instance(c1), Type::Instance(c2)];
+        let id = store.add_union(file_id, &elems);
+        assert_eq!(
+            store.get_union(id).elements,
+            elems.into_iter().collect::<FxIndexSet<_>>()
+        );
+        let union = Type::Union(id);
+        assert_eq!(format!("{}", union.display(&store)), "(C1 | C2)");
+    }
+
+    #[test]
+    fn add_intersection() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let c1 = store.add_class(file_id, "C1");
+        let c2 = store.add_class(file_id, "C2");
+        let c3 = store.add_class(file_id, "C3");
+        let pos = vec![Type::Instance(c1), Type::Instance(c2)];
+        let neg = vec![Type::Instance(c3)];
+        let id = store.add_intersection(file_id, &pos, &neg);
+        assert_eq!(
+            store.get_intersection(id).positive,
+            pos.into_iter().collect::<FxIndexSet<_>>()
+        );
+        assert_eq!(
+            store.get_intersection(id).negative,
+            neg.into_iter().collect::<FxIndexSet<_>>()
+        );
+        let intersection = Type::Intersection(id);
+        assert_eq!(
+            format!("{}", intersection.display(&store)),
+            "(C1 & C2 & ~C3)"
+        );
+    }
+}

crates/red_knot/src/types/infer.rs

@@ -0,0 +1,164 @@
+#![allow(dead_code)]
+use crate::db::{HasJar, SemanticDb, SemanticJar};
+use crate::module::ModuleName;
+use crate::symbols::{Definition, ImportFromDefinition, SymbolId};
+use crate::types::Type;
+use crate::FileId;
+use ruff_python_ast::AstNode;
+
+#[tracing::instrument(level = "trace", skip(db))]
+pub fn infer_symbol_type<Db>(db: &Db, file_id: FileId, symbol_id: SymbolId) -> Type
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    let symbols = db.symbol_table(file_id);
+    let defs = symbols.defs(symbol_id);
+
+    if let Some(ty) = db
+        .jar()
+        .type_store
+        .get_cached_symbol_type(file_id, symbol_id)
+    {
+        return ty;
+    }
+
+    // TODO handle multiple defs, conditional defs...
+    assert_eq!(defs.len(), 1);
+
+    let ty = match &defs[0] {
+        Definition::ImportFrom(ImportFromDefinition {
+            module,
+            name,
+            level,
+        }) => {
+            // TODO relative imports
+            assert!(matches!(level, 0));
+            let module_name = ModuleName::new(module.as_ref().expect("TODO relative imports"));
+            if let Some(module) = db.resolve_module(module_name.clone()) {
+                let remote_file_id = module.path(db).file();
+                let remote_symbols = db.symbol_table(remote_file_id);
+                if let Some(remote_symbol_id) = remote_symbols.root_symbol_id_by_name(name) {
+                    // TODO integrate this into module and symbol-resolution APIs (requiring a
+                    // "requester" argument) so that it doesn't have to be remembered
+                    db.jar().type_store.record_symbol_dependency(
+                        (file_id, symbol_id),
+                        (remote_file_id, remote_symbol_id),
+                    );
+                    db.infer_symbol_type(remote_file_id, remote_symbol_id)
+                } else {
+                    db.jar()
+                        .type_store
+                        .record_module_dependency((file_id, symbol_id), module_name);
+                    Type::Unknown
+                }
+            } else {
+                db.jar()
+                    .type_store
+                    .record_module_dependency((file_id, symbol_id), module_name);
+                Type::Unknown
+            }
+        }
+        Definition::ClassDef(node_key) => {
+            if let Some(ty) = db
+                .jar()
+                .type_store
+                .get_cached_node_type(file_id, node_key.erased())
+            {
+                ty
+            } else {
+                let parsed = db.parse(file_id);
+                let ast = parsed.ast();
+                let node = node_key.resolve_unwrap(ast.as_any_node_ref());
+
+                let store = &db.jar().type_store;
+                let ty = Type::Class(store.add_class(file_id, &node.name.id));
+                store.cache_node_type(file_id, *node_key.erased(), ty);
+                ty
+            }
+        }
+        _ => todo!("other kinds of definitions"),
+    };
+
+    db.jar()
+        .type_store
+        .cache_symbol_type(file_id, symbol_id, ty);
+    ty
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::db::tests::TestDb;
+    use crate::db::{HasJar, SemanticDb, SemanticJar};
+    use crate::module::{ModuleName, ModuleSearchPath, ModuleSearchPathKind};
+    use crate::types::Type;
+
+    // TODO with virtual filesystem we shouldn't have to write files to disk for these
+    // tests
+
+    struct TestCase {
+        temp_dir: tempfile::TempDir,
+        db: TestDb,
+
+        src: ModuleSearchPath,
+    }
+
+    fn create_test() -> std::io::Result<TestCase> {
+        let temp_dir = tempfile::tempdir()?;
+
+        let src = temp_dir.path().join("src");
+        std::fs::create_dir(&src)?;
+        let src = ModuleSearchPath::new(src.canonicalize()?, ModuleSearchPathKind::FirstParty);
+
+        let roots = vec![src.clone()];
+
+        let mut db = TestDb::default();
+        db.set_module_search_paths(roots);
+
+        Ok(TestCase { temp_dir, db, src })
+    }
+
+    #[test]
+    fn follow_import_to_class() -> std::io::Result<()> {
+        let TestCase {
+            src,
+            db,
+            temp_dir: _temp_dir,
+        } = create_test()?;
+
+        let a_path = src.path().join("a.py");
+        let b_path = src.path().join("b.py");
+        std::fs::write(a_path, "from b import C as D")?;
+        std::fs::write(b_path, "class C: pass")?;
+        let a_file = db
+            .resolve_module(ModuleName::new("a"))
+            .expect("module should be found")
+            .path(&db)
+            .file();
+        let a_syms = db.symbol_table(a_file);
+        let d_sym = a_syms
+            .root_symbol_id_by_name("D")
+            .expect("D symbol should be found");
+
+        let ty = db.infer_symbol_type(a_file, d_sym);
+
+        let b_file = db
+            .resolve_module(ModuleName::new("b"))
+            .expect("module should be found")
+            .path(&db)
+            .file();
+        let b_syms = db.symbol_table(b_file);
+        let c_sym = b_syms
+            .root_symbol_id_by_name("C")
+            .expect("C symbol should be found");
+
+        let jar = HasJar::<SemanticJar>::jar(&db);
+
+        assert!(matches!(ty, Type::Class(_)));
+        assert_eq!(format!("{}", ty.display(&jar.type_store)), "Literal[C]");
+        assert_eq!(
+            jar.type_store.get_module(a_file).symbol_dependencies[&d_sym],
+            [(b_file, c_sym)].iter().copied().collect()
+        );
+        Ok(())
+    }
+}

crates/red_knot/src/verbosity.rs

@@ -1 +0,0 @@
-

crates/red_knot/src/watch.rs

@@ -0,0 +1,78 @@
+use anyhow::Context;
+use std::path::Path;
+
+use crate::files::Files;
+use crate::program::{FileChange, FileChangeKind};
+use notify::event::{CreateKind, RemoveKind};
+use notify::{recommended_watcher, Event, EventKind, RecommendedWatcher, RecursiveMode, Watcher};
+
+pub struct FileWatcher {
+    watcher: RecommendedWatcher,
+}
+
+pub trait EventHandler: Send + 'static {
+    fn handle(&self, changes: Vec<FileChange>);
+}
+
+impl<F> EventHandler for F
+where
+    F: Fn(Vec<FileChange>) + Send + 'static,
+{
+    fn handle(&self, changes: Vec<FileChange>) {
+        let f = self;
+        f(changes);
+    }
+}
+
+impl FileWatcher {
+    pub fn new<E>(handler: E, files: Files) -> anyhow::Result<Self>
+    where
+        E: EventHandler,
+    {
+        Self::from_handler(Box::new(handler), files)
+    }
+
+    fn from_handler(handler: Box<dyn EventHandler>, files: Files) -> anyhow::Result<Self> {
+        let watcher = recommended_watcher(move |changes: notify::Result<Event>| {
+            match changes {
+                Ok(event) => {
+                    // TODO verify that this handles all events correctly
+                    let change_kind = match event.kind {
+                        EventKind::Create(CreateKind::File) => FileChangeKind::Created,
+                        EventKind::Modify(_) => FileChangeKind::Modified,
+                        EventKind::Remove(RemoveKind::File) => FileChangeKind::Deleted,
+                        _ => {
+                            return;
+                        }
+                    };
+
+                    let mut changes = Vec::new();
+
+                    for path in event.paths {
+                        if path.is_file() {
+                            let id = files.intern(&path);
+                            changes.push(FileChange::new(id, change_kind));
+                        }
+                    }
+
+                    if !changes.is_empty() {
+                        handler.handle(changes);
+                    }
+                }
+                // TODO proper error handling
+                Err(err) => {
+                    panic!("Error: {err}");
+                }
+            }
+        })
+        .context("Failed to create file watcher.")?;
+
+        Ok(Self { watcher })
+    }
+
+    pub fn watch_folder(&mut self, path: &Path) -> anyhow::Result<()> {
+        self.watcher.watch(path, RecursiveMode::Recursive)?;
+
+        Ok(())
+    }
+}

crates/red_knot_python_semantic/Cargo.toml

@@ -1,54 +0,0 @@
-[package]
-name = "red_knot_python_semantic"
-version = "0.0.0"
-publish = false
-authors = { workspace = true }
-edition = { workspace = true }
-rust-version = { workspace = true }
-homepage = { workspace = true }
-documentation = { workspace = true }
-repository = { workspace = true }
-license = { workspace = true }
-
-[dependencies]
-ruff_db = { workspace = true }
-ruff_index = { workspace = true }
-ruff_python_ast = { workspace = true }
-ruff_python_parser = { workspace = true }
-ruff_python_stdlib = { workspace = true }
-ruff_source_file = { workspace = true }
-ruff_text_size = { workspace = true }
-ruff_python_literal = { workspace = true }
-
-anyhow = { workspace = true }
-bitflags = { workspace = true }
-camino = { workspace = true }
-compact_str = { workspace = true }
-countme = { workspace = true }
-indexmap = { workspace = true }
-itertools = { workspace = true }
-ordermap = { workspace = true }
-salsa = { workspace = true }
-thiserror = { workspace = true }
-tracing = { workspace = true }
-rustc-hash = { workspace = true }
-hashbrown = { workspace = true }
-serde = { workspace = true, optional = true }
-smallvec = { workspace = true }
-static_assertions = { workspace = true }
-test-case = { workspace = true }
-memchr = { workspace = true }
-
-[dev-dependencies]
-ruff_db = { workspace = true, features = ["os", "testing"] }
-ruff_python_parser = { workspace = true }
-red_knot_test = { workspace = true }
-red_knot_vendored = { workspace = true }
-
-anyhow = { workspace = true }
-dir-test = { workspace = true }
-insta = { workspace = true }
-tempfile = { workspace = true }
-
-[lints]
-workspace = true

crates/red_knot_python_semantic/build.rs

@@ -1,4 +0,0 @@
-/// Rebuild the crate if a test file is added or removed from
-pub fn main() {
-    println!("cargo::rerun-if-changed=resources/mdtest");
-}

crates/red_knot_python_semantic/resources/README.md

@@ -1,4 +0,0 @@
-Markdown files within the `mdtest/` subdirectory are tests of type inference and type checking;
-executed by the `tests/mdtest.rs` integration test.
-
-See `crates/red_knot_test/README.md` for documentation of this test format.

crates/red_knot_python_semantic/resources/mdtest/.mdformat.toml

@@ -1 +0,0 @@
-wrap = 100

crates/red_knot_python_semantic/resources/mdtest/annotations/never.md

@@ -1,62 +0,0 @@
-# NoReturn & Never
-
-`NoReturn` is used to annotate the return type for functions that never return. `Never` is the
-bottom type, representing the empty set of Python objects. These two annotations can be used
-interchangeably.
-
-## Function Return Type Annotation
-
-```py
-from typing import NoReturn
-
-def stop() -> NoReturn:
-    raise RuntimeError("no way")
-
-# revealed: Never
-reveal_type(stop())
-```
-
-## Assignment
-
-```py
-from typing import NoReturn, Never, Any
-
-# error: [invalid-type-parameter] "Type `typing.Never` expected no type parameter"
-x: Never[int]
-a1: NoReturn
-# TODO: Test `Never` is only available in python >= 3.11
-a2: Never
-b1: Any
-b2: int
-
-def f():
-    # revealed: Never
-    reveal_type(a1)
-    # revealed: Never
-    reveal_type(a2)
-
-    # Never is assignable to all types.
-    v1: int = a1
-    v2: str = a1
-    # Other types are not assignable to Never except for Never (and Any).
-    v3: Never = b1
-    v4: Never = a2
-    v5: Any = b2
-    # error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `Never`"
-    v6: Never = 1
-```
-
-## Typing Extensions
-
-```py
-from typing_extensions import NoReturn, Never
-
-x: NoReturn
-y: Never
-
-def f():
-    # revealed: Never
-    reveal_type(x)
-    # revealed: Never
-    reveal_type(y)
-```

crates/red_knot_python_semantic/resources/mdtest/annotations/optional.md

@@ -1,47 +0,0 @@
-# Optional
-
-## Annotation
-
-`typing.Optional` is equivalent to using the type with a None in a Union.
-
-```py
-from typing import Optional
-
-a: Optional[int]
-a1: Optional[bool]
-a2: Optional[Optional[bool]]
-a3: Optional[None]
-
-def f():
-    # revealed: int | None
-    reveal_type(a)
-    # revealed: bool | None
-    reveal_type(a1)
-    # revealed: bool | None
-    reveal_type(a2)
-    # revealed: None
-    reveal_type(a3)
-```
-
-## Assignment
-
-```py
-from typing import Optional
-
-a: Optional[int] = 1
-a = None
-# error: [invalid-assignment] "Object of type `Literal[""]` is not assignable to `int | None`"
-a = ""
-```
-
-## Typing Extensions
-
-```py
-from typing_extensions import Optional
-
-a: Optional[int]
-
-def f():
-    # revealed: int | None
-    reveal_type(a)
-```

crates/red_knot_python_semantic/resources/mdtest/annotations/starred.md

@@ -1,18 +0,0 @@
-# Starred expression annotations
-
-Type annotations for `*args` can be starred expressions themselves:
-
-```py
-from typing_extensions import TypeVarTuple
-
-Ts = TypeVarTuple("Ts")
-
-def append_int(*args: *Ts) -> tuple[*Ts, int]:
-    # TODO: should show some representation of the variadic generic type
-    reveal_type(args)  # revealed: @Todo(function parameter type)
-
-    return (*args, 1)
-
-# TODO should be tuple[Literal[True], Literal["a"], int]
-reveal_type(append_int(True, "a"))  # revealed: @Todo(full tuple[...] support)
-```

crates/red_knot_python_semantic/resources/mdtest/annotations/string.md

@@ -1,218 +0,0 @@
-# String annotations
-
-## Simple
-
-```py
-def f() -> "int":
-    return 1
-
-reveal_type(f())  # revealed: int
-```
-
-## Nested
-
-```py
-def f() -> "'int'":
-    return 1
-
-reveal_type(f())  # revealed: int
-```
-
-## Type expression
-
-```py
-def f1() -> "int | str":
-    return 1
-
-def f2() -> "tuple[int, str]":
-    return 1
-
-reveal_type(f1())  # revealed: int | str
-reveal_type(f2())  # revealed: tuple[int, str]
-```
-
-## Partial
-
-```py
-def f() -> tuple[int, "str"]:
-    return 1
-
-reveal_type(f())  # revealed: tuple[int, str]
-```
-
-## Deferred
-
-```py
-def f() -> "Foo":
-    return Foo()
-
-class Foo:
-    pass
-
-reveal_type(f())  # revealed: Foo
-```
-
-## Deferred (undefined)
-
-```py
-# error: [unresolved-reference]
-def f() -> "Foo":
-    pass
-
-reveal_type(f())  # revealed: Unknown
-```
-
-## Partial deferred
-
-```py
-def f() -> int | "Foo":
-    return 1
-
-class Foo:
-    pass
-
-reveal_type(f())  # revealed: int | Foo
-```
-
-## `typing.Literal`
-
-```py
-from typing import Literal
-
-def f1() -> Literal["Foo", "Bar"]:
-    return "Foo"
-
-def f2() -> 'Literal["Foo", "Bar"]':
-    return "Foo"
-
-class Foo:
-    pass
-
-reveal_type(f1())  # revealed: Literal["Foo", "Bar"]
-reveal_type(f2())  # revealed: Literal["Foo", "Bar"]
-```
-
-## Various string kinds
-
-```py
-# error: [annotation-raw-string] "Type expressions cannot use raw string literal"
-def f1() -> r"int":
-    return 1
-
-# error: [annotation-f-string] "Type expressions cannot use f-strings"
-def f2() -> f"int":
-    return 1
-
-# error: [annotation-byte-string] "Type expressions cannot use bytes literal"
-def f3() -> b"int":
-    return 1
-
-def f4() -> "int":
-    return 1
-
-# error: [annotation-implicit-concat] "Type expressions cannot span multiple string literals"
-def f5() -> "in" "t":
-    return 1
-
-# error: [annotation-escape-character] "Type expressions cannot contain escape characters"
-def f6() -> "\N{LATIN SMALL LETTER I}nt":
-    return 1
-
-# error: [annotation-escape-character] "Type expressions cannot contain escape characters"
-def f7() -> "\x69nt":
-    return 1
-
-def f8() -> """int""":
-    return 1
-
-def f9() -> "b'int'":
-    return 1
-
-reveal_type(f1())  # revealed: Unknown
-reveal_type(f2())  # revealed: Unknown
-reveal_type(f3())  # revealed: Unknown
-reveal_type(f4())  # revealed: int
-reveal_type(f5())  # revealed: Unknown
-reveal_type(f6())  # revealed: Unknown
-reveal_type(f7())  # revealed: Unknown
-reveal_type(f8())  # revealed: int
-reveal_type(f9())  # revealed: Unknown
-```
-
-## Various string kinds in `typing.Literal`
-
-```py
-from typing import Literal
-
-def f() -> Literal["a", r"b", b"c", "d" "e", "\N{LATIN SMALL LETTER F}", "\x67", """h"""]:
-    return "normal"
-
-reveal_type(f())  # revealed: Literal["a", "b", "de", "f", "g", "h"] | Literal[b"c"]
-```
-
-## Class variables
-
-```py
-MyType = int
-
-class Aliases:
-    MyType = str
-
-    forward: "MyType"
-    not_forward: MyType
-
-reveal_type(Aliases.forward)  # revealed: str
-reveal_type(Aliases.not_forward)  # revealed: str
-```
-
-## Annotated assignment
-
-```py
-a: "int" = 1
-b: "'int'" = 1
-c: "Foo"
-# error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `Foo`"
-d: "Foo" = 1
-
-class Foo:
-    pass
-
-c = Foo()
-
-reveal_type(a)  # revealed: Literal[1]
-reveal_type(b)  # revealed: Literal[1]
-reveal_type(c)  # revealed: Foo
-reveal_type(d)  # revealed: Foo
-```
-
-## Parameter
-
-TODO: Add tests once parameter inference is supported
-
-## Invalid expressions
-
-The expressions in these string annotations aren't valid expressions in this context but we
-shouldn't panic.
-
-```py
-a: "1 or 2"
-b: "(x := 1)"
-c: "1 + 2"
-d: "lambda x: x"
-e: "x if True else y"
-f: "{'a': 1, 'b': 2}"
-g: "{1, 2}"
-h: "[i for i in range(5)]"
-i: "{i for i in range(5)}"
-j: "{i: i for i in range(5)}"
-k: "(i for i in range(5))"
-l: "await 1"
-# error: [forward-annotation-syntax-error]
-m: "yield 1"
-# error: [forward-annotation-syntax-error]
-n: "yield from 1"
-o: "1 < 2"
-p: "call()"
-r: "[1, 2]"
-s: "(1, 2)"
-```

crates/red_knot_python_semantic/resources/mdtest/annotations/union.md

@@ -1,61 +0,0 @@
-# Union
-
-## Annotation
-
-`typing.Union` can be used to construct union types same as `|` operator.
-
-```py
-from typing import Union
-
-a: Union[int, str]
-a1: Union[int, bool]
-a2: Union[int, Union[float, str]]
-a3: Union[int, None]
-a4: Union[Union[float, str]]
-a5: Union[int]
-a6: Union[()]
-
-def f():
-    # revealed: int | str
-    reveal_type(a)
-    # Since bool is a subtype of int we simplify to int here. But we do allow assigning boolean values (see below).
-    # revealed: int
-    reveal_type(a1)
-    # revealed: int | float | str
-    reveal_type(a2)
-    # revealed: int | None
-    reveal_type(a3)
-    # revealed: float | str
-    reveal_type(a4)
-    # revealed: int
-    reveal_type(a5)
-    # revealed: Never
-    reveal_type(a6)
-```
-
-## Assignment
-
-```py
-from typing import Union
-
-a: Union[int, str]
-a = 1
-a = ""
-a1: Union[int, bool]
-a1 = 1
-a1 = True
-# error: [invalid-assignment] "Object of type `Literal[b""]` is not assignable to `int | str`"
-a = b""
-```
-
-## Typing Extensions
-
-```py
-from typing_extensions import Union
-
-a: Union[int, str]
-
-def f():
-    # revealed: int | str
-    reveal_type(a)
-```

crates/red_knot_python_semantic/resources/mdtest/assignment/annotations.md

@@ -1,138 +0,0 @@
-# Assignment with annotations
-
-## Annotation only transparent to local inference
-
-```py
-x = 1
-x: int
-y = x
-
-reveal_type(y)  # revealed: Literal[1]
-```
-
-## Violates own annotation
-
-```py
-x: int = "foo"  # error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `int`"
-```
-
-## Violates previous annotation
-
-```py
-x: int
-x = "foo"  # error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `int`"
-```
-
-## Tuple annotations are understood
-
-```py path=module.py
-from typing_extensions import Unpack
-
-a: tuple[()] = ()
-b: tuple[int] = (42,)
-c: tuple[str, int] = ("42", 42)
-d: tuple[tuple[str, str], tuple[int, int]] = (("foo", "foo"), (42, 42))
-e: tuple[str, ...] = ()
-# TODO: we should not emit this error
-# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[tuple]` is possibly unbound"
-f: tuple[str, *tuple[int, ...], bytes] = ("42", b"42")
-g: tuple[str, Unpack[tuple[int, ...]], bytes] = ("42", b"42")
-h: tuple[list[int], list[int]] = ([], [])
-i: tuple[str | int, str | int] = (42, 42)
-j: tuple[str | int] = (42,)
-```
-
-```py path=script.py
-from module import a, b, c, d, e, f, g, h, i, j
-
-reveal_type(a)  # revealed: tuple[()]
-reveal_type(b)  # revealed: tuple[int]
-reveal_type(c)  # revealed: tuple[str, int]
-reveal_type(d)  # revealed: tuple[tuple[str, str], tuple[int, int]]
-
-# TODO: homogenous tuples, PEP-646 tuples
-reveal_type(e)  # revealed: @Todo(full tuple[...] support)
-reveal_type(f)  # revealed: @Todo(full tuple[...] support)
-reveal_type(g)  # revealed: @Todo(full tuple[...] support)
-
-# TODO: support more kinds of type expressions in annotations
-reveal_type(h)  # revealed: @Todo(full tuple[...] support)
-
-reveal_type(i)  # revealed: tuple[str | int, str | int]
-reveal_type(j)  # revealed: tuple[str | int]
-```
-
-## Incorrect tuple assignments are complained about
-
-```py
-# error: [invalid-assignment] "Object of type `tuple[Literal[1], Literal[2]]` is not assignable to `tuple[()]`"
-a: tuple[()] = (1, 2)
-
-# error: [invalid-assignment] "Object of type `tuple[Literal["foo"]]` is not assignable to `tuple[int]`"
-b: tuple[int] = ("foo",)
-
-# error: [invalid-assignment] "Object of type `tuple[list, Literal["foo"]]` is not assignable to `tuple[str | int, str]`"
-c: tuple[str | int, str] = ([], "foo")
-```
-
-## PEP-604 annotations are supported
-
-```py
-def foo() -> str | int | None:
-    return None
-
-reveal_type(foo())  # revealed: str | int | None
-
-def bar() -> str | str | None:
-    return None
-
-reveal_type(bar())  # revealed: str | None
-
-def baz() -> str | str:
-    return "Hello, world!"
-
-reveal_type(baz())  # revealed: str
-```
-
-## Attribute expressions in type annotations are understood
-
-```py
-import builtins
-
-int = "foo"
-a: builtins.int = 42
-
-# error: [invalid-assignment] "Object of type `Literal["bar"]` is not assignable to `int`"
-b: builtins.int = "bar"
-
-c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = ((42, 42), 42)
-
-# error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `tuple[tuple[int, int], int]`"
-c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = "foo"
-```
-
-## Future annotations are deferred
-
-```py
-from __future__ import annotations
-
-x: Foo
-
-class Foo:
-    pass
-
-x = Foo()
-reveal_type(x)  # revealed: Foo
-```
-
-## Annotations in stub files are deferred
-
-```pyi path=main.pyi
-x: Foo
-
-class Foo:
-    pass
-
-x = Foo()
-reveal_type(x)  # revealed: Foo
-```

crates/red_knot_python_semantic/resources/mdtest/assignment/augmented.md

@@ -1,182 +0,0 @@
-# Augmented assignment
-
-## Basic
-
-```py
-x = 3
-x -= 1
-reveal_type(x)  # revealed: Literal[2]
-
-x = 1.0
-x /= 2
-reveal_type(x)  # revealed: float
-```
-
-## Dunder methods
-
-```py
-class C:
-    def __isub__(self, other: int) -> str:
-        return "Hello, world!"
-
-x = C()
-x -= 1
-reveal_type(x)  # revealed: str
-
-class C:
-    def __iadd__(self, other: str) -> float:
-        return 1.0
-
-x = C()
-x += "Hello"
-reveal_type(x)  # revealed: float
-```
-
-## Unsupported types
-
-```py
-class C:
-    def __isub__(self, other: str) -> int:
-        return 42
-
-x = C()
-x -= 1
-
-# TODO: should error, once operand type check is implemented
-reveal_type(x)  # revealed: int
-```
-
-## Method union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    if bool_instance():
-        def __iadd__(self, other: int) -> str:
-            return "Hello, world!"
-    else:
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-f = Foo()
-f += 12
-
-reveal_type(f)  # revealed: str | int
-```
-
-## Partially bound `__iadd__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    if bool_instance():
-        def __iadd__(self, other: str) -> int:
-            return 42
-
-f = Foo()
-
-# TODO: We should emit an `unsupported-operator` error here, possibly with the information
-# that `Foo.__iadd__` may be unbound as additional context.
-f += "Hello, world!"
-
-reveal_type(f)  # revealed: int | Unknown
-```
-
-## Partially bound with `__add__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    def __add__(self, other: str) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: str) -> int:
-            return 42
-
-f = Foo()
-f += "Hello, world!"
-
-reveal_type(f)  # revealed: int | str
-```
-
-## Partially bound target union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    def __add__(self, other: int) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-if bool_instance():
-    f = Foo()
-else:
-    f = 42.0
-f += 12
-
-reveal_type(f)  # revealed: int | str | float
-```
-
-## Target union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    def __iadd__(self, other: int) -> str:
-        return "Hello, world!"
-
-if flag:
-    f = Foo()
-else:
-    f = 42.0
-f += 12
-
-reveal_type(f)  # revealed: str | float
-```
-
-## Partially bound target union with `__add__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    def __add__(self, other: int) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-class Bar:
-    def __add__(self, other: int) -> bytes:
-        return b"Hello, world!"
-
-    def __iadd__(self, other: int) -> float:
-        return 42.0
-
-if flag:
-    f = Foo()
-else:
-    f = Bar()
-f += 12
-
-reveal_type(f)  # revealed: int | str | float
-```

crates/red_knot_python_semantic/resources/mdtest/assignment/multi_target.md

@@ -1,9 +0,0 @@
-# Multi-target assignment
-
-## Basic
-
-```py
-x = y = 1
-reveal_type(x)  # revealed: Literal[1]
-reveal_type(y)  # revealed: Literal[1]
-```

crates/red_knot_python_semantic/resources/mdtest/assignment/unbound.md

@@ -1,60 +0,0 @@
-# Unbound
-
-## Unbound
-
-```py
-x = foo  # error: [unresolved-reference] "Name `foo` used when not defined"
-foo = 1
-
-# No error `unresolved-reference` diagnostic is reported for `x`. This is
-# desirable because we would get a lot of cascading errors even though there
-# is only one root cause (the unbound variable `foo`).
-
-# revealed: Unknown
-reveal_type(x)
-```
-
-Note: in this particular example, one could argue that the most likely error would be a wrong order
-of the `x`/`foo` definitions, and so it could be desirable to infer `Literal[1]` for the type of
-`x`. On the other hand, there might be a variable `fob` a little higher up in this file, and the
-actual error might have been just a typo. Inferring `Unknown` thus seems like the safest option.
-
-## Unbound class variable
-
-Name lookups within a class scope fall back to globals, but lookups of class attributes don't.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-x = 1
-
-class C:
-    y = x
-    if flag:
-        x = 2
-
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C]` is possibly unbound"
-reveal_type(C.x)  # revealed: Literal[2]
-reveal_type(C.y)  # revealed: Literal[1]
-```
-
-## Possibly unbound in class and global scope
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance():
-    x = "abc"
-
-class C:
-    if bool_instance():
-        x = 1
-
-    # error: [possibly-unresolved-reference]
-    y = x
-
-reveal_type(C.y)  # revealed: Literal[1] | Literal["abc"]
-```

crates/red_knot_python_semantic/resources/mdtest/assignment/walrus.md

@@ -1,17 +0,0 @@
-# Walrus operator
-
-## Basic
-
-```py
-x = (y := 1) + 1
-reveal_type(x)  # revealed: Literal[2]
-reveal_type(y)  # revealed: Literal[1]
-```
-
-## Walrus self-addition
-
-```py
-x = 0
-(x := x + 1)
-reveal_type(x)  # revealed: Literal[1]
-```

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -1,136 +0,0 @@
-# Class attributes
-
-## Union of attributes
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-if flag:
-    class C1:
-        x = 1
-
-else:
-    class C1:
-        x = 2
-
-class C2:
-    if flag:
-        x = 3
-    else:
-        x = 4
-
-reveal_type(C1.x)  # revealed: Literal[1, 2]
-reveal_type(C2.x)  # revealed: Literal[3, 4]
-```
-
-## Inherited attributes
-
-```py
-class A:
-    X = "foo"
-
-class B(A): ...
-class C(B): ...
-
-reveal_type(C.X)  # revealed: Literal["foo"]
-```
-
-## Inherited attributes (multiple inheritance)
-
-```py
-class O: ...
-
-class F(O):
-    X = 56
-
-class E(O):
-    X = 42
-
-class D(O): ...
-class C(D, F): ...
-class B(E, D): ...
-class A(B, C): ...
-
-# revealed: tuple[Literal[A], Literal[B], Literal[E], Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(A.__mro__)
-
-# `E` is earlier in the MRO than `F`, so we should use the type of `E.X`
-reveal_type(A.X)  # revealed: Literal[42]
-```
-
-## Unions with possibly unbound paths
-
-### Definite boundness within a class
-
-In this example, the `x` attribute is not defined in the `C2` element of the union:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1:
-    x = 1
-
-class C2: ...
-
-class C3:
-    x = 3
-
-flag1 = bool_instance()
-flag2 = bool_instance()
-
-C = C1 if flag1 else C2 if flag2 else C3
-
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-reveal_type(C.x)  # revealed: Literal[1, 3]
-```
-
-### Possibly-unbound within a class
-
-We raise the same diagnostic if the attribute is possibly-unbound in at least one element of the
-union:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1:
-    x = 1
-
-class C2:
-    if bool_instance():
-        x = 2
-
-class C3:
-    x = 3
-
-flag1 = bool_instance()
-flag2 = bool_instance()
-
-C = C1 if flag1 else C2 if flag2 else C3
-
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-reveal_type(C.x)  # revealed: Literal[1, 2, 3]
-```
-
-## Unions with all paths unbound
-
-If the symbol is unbound in all elements of the union, we detect that:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1: ...
-class C2: ...
-
-flag = bool_instance()
-
-C = C1 if flag else C2
-
-# error: [unresolved-attribute] "Type `Literal[C1, C2]` has no attribute `x`"
-reveal_type(C.x)  # revealed: Unknown
-```

crates/red_knot_python_semantic/resources/mdtest/binary/booleans.md

@@ -1,48 +0,0 @@
-## Binary operations on booleans
-
-## Basic Arithmetic
-
-We try to be precise and all operations except for division will result in Literal type.
-
-```py
-a = True
-b = False
-
-reveal_type(a + a)  # revealed: Literal[2]
-reveal_type(a + b)  # revealed: Literal[1]
-reveal_type(b + a)  # revealed: Literal[1]
-reveal_type(b + b)  # revealed: Literal[0]
-
-reveal_type(a - a)  # revealed: Literal[0]
-reveal_type(a - b)  # revealed: Literal[1]
-reveal_type(b - a)  # revealed: Literal[-1]
-reveal_type(b - b)  # revealed: Literal[0]
-
-reveal_type(a * a)  # revealed: Literal[1]
-reveal_type(a * b)  # revealed: Literal[0]
-reveal_type(b * a)  # revealed: Literal[0]
-reveal_type(b * b)  # revealed: Literal[0]
-
-reveal_type(a % a)  # revealed: Literal[0]
-reveal_type(b % a)  # revealed: Literal[0]
-
-reveal_type(a // a)  # revealed: Literal[1]
-reveal_type(b // a)  # revealed: Literal[0]
-
-reveal_type(a**a)  # revealed: Literal[1]
-reveal_type(a**b)  # revealed: Literal[1]
-reveal_type(b**a)  # revealed: Literal[0]
-reveal_type(b**b)  # revealed: Literal[1]
-
-# Division
-reveal_type(a / a)  # revealed: float
-reveal_type(b / a)  # revealed: float
-b / b  # error: [division-by-zero] "Cannot divide object of type `Literal[False]` by zero"
-a / b  # error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
-
-# bitwise OR
-reveal_type(a | a)  # revealed: Literal[True]
-reveal_type(a | b)  # revealed: Literal[True]
-reveal_type(b | a)  # revealed: Literal[True]
-reveal_type(b | b)  # revealed: Literal[False]
-```

crates/red_knot_python_semantic/resources/mdtest/binary/instances.md

@@ -1,435 +0,0 @@
-# Binary operations on instances
-
-Binary operations in Python are implemented by means of magic double-underscore methods.
-
-For references, see:
-
-- <https://snarky.ca/unravelling-binary-arithmetic-operations-in-python/>
-- <https://docs.python.org/3/reference/datamodel.html#emulating-numeric-types>
-
-## Operations
-
-We support inference for all Python's binary operators: `+`, `-`, `*`, `@`, `/`, `//`, `%`, `**`,
-`<<`, `>>`, `&`, `^`, and `|`.
-
-```py
-class A:
-    def __add__(self, other) -> A:
-        return self
-
-    def __sub__(self, other) -> A:
-        return self
-
-    def __mul__(self, other) -> A:
-        return self
-
-    def __matmul__(self, other) -> A:
-        return self
-
-    def __truediv__(self, other) -> A:
-        return self
-
-    def __floordiv__(self, other) -> A:
-        return self
-
-    def __mod__(self, other) -> A:
-        return self
-
-    def __pow__(self, other) -> A:
-        return self
-
-    def __lshift__(self, other) -> A:
-        return self
-
-    def __rshift__(self, other) -> A:
-        return self
-
-    def __and__(self, other) -> A:
-        return self
-
-    def __xor__(self, other) -> A:
-        return self
-
-    def __or__(self, other) -> A:
-        return self
-
-class B: ...
-
-reveal_type(A() + B())  # revealed: A
-reveal_type(A() - B())  # revealed: A
-reveal_type(A() * B())  # revealed: A
-reveal_type(A() @ B())  # revealed: A
-reveal_type(A() / B())  # revealed: A
-reveal_type(A() // B())  # revealed: A
-reveal_type(A() % B())  # revealed: A
-reveal_type(A() ** B())  # revealed: A
-reveal_type(A() << B())  # revealed: A
-reveal_type(A() >> B())  # revealed: A
-reveal_type(A() & B())  # revealed: A
-reveal_type(A() ^ B())  # revealed: A
-reveal_type(A() | B())  # revealed: A
-```
-
-## Reflected
-
-We also support inference for reflected operations:
-
-```py
-class A:
-    def __radd__(self, other) -> A:
-        return self
-
-    def __rsub__(self, other) -> A:
-        return self
-
-    def __rmul__(self, other) -> A:
-        return self
-
-    def __rmatmul__(self, other) -> A:
-        return self
-
-    def __rtruediv__(self, other) -> A:
-        return self
-
-    def __rfloordiv__(self, other) -> A:
-        return self
-
-    def __rmod__(self, other) -> A:
-        return self
-
-    def __rpow__(self, other) -> A:
-        return self
-
-    def __rlshift__(self, other) -> A:
-        return self
-
-    def __rrshift__(self, other) -> A:
-        return self
-
-    def __rand__(self, other) -> A:
-        return self
-
-    def __rxor__(self, other) -> A:
-        return self
-
-    def __ror__(self, other) -> A:
-        return self
-
-class B: ...
-
-reveal_type(B() + A())  # revealed: A
-reveal_type(B() - A())  # revealed: A
-reveal_type(B() * A())  # revealed: A
-reveal_type(B() @ A())  # revealed: A
-reveal_type(B() / A())  # revealed: A
-reveal_type(B() // A())  # revealed: A
-reveal_type(B() % A())  # revealed: A
-reveal_type(B() ** A())  # revealed: A
-reveal_type(B() << A())  # revealed: A
-reveal_type(B() >> A())  # revealed: A
-reveal_type(B() & A())  # revealed: A
-reveal_type(B() ^ A())  # revealed: A
-reveal_type(B() | A())  # revealed: A
-```
-
-## Returning a different type
-
-The magic methods aren't required to return the type of `self`:
-
-```py
-class A:
-    def __add__(self, other) -> int:
-        return 1
-
-    def __rsub__(self, other) -> int:
-        return 1
-
-class B: ...
-
-reveal_type(A() + B())  # revealed: int
-reveal_type(B() - A())  # revealed: int
-```
-
-## Non-reflected precedence in general
-
-In general, if the left-hand side defines `__add__` and the right-hand side defines `__radd__` and
-the right-hand side is not a subtype of the left-hand side, `lhs.__add__` will take precedence:
-
-```py
-class A:
-    def __add__(self, other: B) -> int:
-        return 42
-
-class B:
-    def __radd__(self, other: A) -> str:
-        return "foo"
-
-reveal_type(A() + B())  # revealed:  int
-
-# Edge case: C is a subtype of C, *but* if the two sides are of *equal* types,
-# the lhs *still* takes precedence
-class C:
-    def __add__(self, other: C) -> int:
-        return 42
-
-    def __radd__(self, other: C) -> str:
-        return "foo"
-
-reveal_type(C() + C())  # revealed: int
-```
-
-## Reflected precedence for subtypes (in some cases)
-
-If the right-hand operand is a subtype of the left-hand operand and has a different implementation
-of the reflected method, the reflected method on the right-hand operand takes precedence.
-
-```py
-class A:
-    def __add__(self, other) -> str:
-        return "foo"
-
-    def __radd__(self, other) -> str:
-        return "foo"
-
-class MyString(str): ...
-
-class B(A):
-    def __radd__(self, other) -> MyString:
-        return MyString()
-
-reveal_type(A() + B())  # revealed: MyString
-
-# N.B. Still a subtype of `A`, even though `A` does not appear directly in the class's `__bases__`
-class C(B): ...
-
-reveal_type(A() + C())  # revealed: MyString
-```
-
-## Reflected precedence 2
-
-If the right-hand operand is a subtype of the left-hand operand, but does not override the reflected
-method, the left-hand operand's non-reflected method still takes precedence:
-
-```py
-class A:
-    def __add__(self, other) -> str:
-        return "foo"
-
-    def __radd__(self, other) -> int:
-        return 42
-
-class B(A): ...
-
-reveal_type(A() + B())  # revealed: str
-```
-
-## Only reflected supported
-
-For example, at runtime, `(1).__add__(1.2)` is `NotImplemented`, but `(1.2).__radd__(1) == 2.2`,
-meaning that `1 + 1.2` succeeds at runtime (producing `2.2`). The runtime tries the second one only
-if the first one returns `NotImplemented` to signal failure.
-
-Typeshed and other stubs annotate dunder-method calls that would return `NotImplemented` as being
-"illegal" calls. `int.__add__` is annotated as only "accepting" `int`s, even though it
-strictly-speaking "accepts" any other object without raising an exception -- it will simply return
-`NotImplemented`, allowing the runtime to try the `__radd__` method of the right-hand operand as
-well.
-
-```py
-class A:
-    def __sub__(self, other: A) -> A:
-        return A()
-
-class B:
-    def __rsub__(self, other: A) -> B:
-        return B()
-
-# TODO: this should be `B` (the return annotation of `B.__rsub__`),
-# because `A.__sub__` is annotated as only accepting `A`,
-# but `B.__rsub__` will accept `A`.
-reveal_type(A() - B())  # revealed: A
-```
-
-## Callable instances as dunders
-
-Believe it or not, this is supported at runtime:
-
-```py
-class A:
-    def __call__(self, other) -> int:
-        return 42
-
-class B:
-    __add__ = A()
-
-reveal_type(B() + B())  # revealed: int
-```
-
-## Integration test: numbers from typeshed
-
-```py
-reveal_type(3j + 3.14)  # revealed: complex
-reveal_type(4.2 + 42)  # revealed: float
-reveal_type(3j + 3)  # revealed: complex
-
-# TODO should be complex, need to check arg type and fall back to `rhs.__radd__`
-reveal_type(3.14 + 3j)  # revealed: float
-
-# TODO should be float, need to check arg type and fall back to `rhs.__radd__`
-reveal_type(42 + 4.2)  # revealed: int
-
-# TODO should be complex, need to check arg type and fall back to `rhs.__radd__`
-reveal_type(3 + 3j)  # revealed: int
-
-def returns_int() -> int:
-    return 42
-
-def returns_bool() -> bool:
-    return True
-
-x = returns_bool()
-y = returns_int()
-
-reveal_type(x + y)  # revealed: int
-reveal_type(4.2 + x)  # revealed: float
-
-# TODO should be float, need to check arg type and fall back to `rhs.__radd__`
-reveal_type(y + 4.12)  # revealed: int
-```
-
-## With literal types
-
-When we have a literal type for one operand, we're able to fall back to the instance handling for
-its instance super-type.
-
-```py
-class A:
-    def __add__(self, other) -> A:
-        return self
-
-    def __radd__(self, other) -> A:
-        return self
-
-reveal_type(A() + 1)  # revealed: A
-# TODO should be `A` since `int.__add__` doesn't support `A` instances
-reveal_type(1 + A())  # revealed: int
-
-reveal_type(A() + "foo")  # revealed: A
-# TODO should be `A` since `str.__add__` doesn't support `A` instances
-# TODO overloads
-reveal_type("foo" + A())  # revealed: @Todo(return type)
-
-reveal_type(A() + b"foo")  # revealed: A
-# TODO should be `A` since `bytes.__add__` doesn't support `A` instances
-reveal_type(b"foo" + A())  # revealed: bytes
-
-reveal_type(A() + ())  # revealed: A
-# TODO this should be `A`, since `tuple.__add__` doesn't support `A` instances
-reveal_type(() + A())  # revealed: @Todo(return type)
-
-literal_string_instance = "foo" * 1_000_000_000
-# the test is not testing what it's meant to be testing if this isn't a `LiteralString`:
-reveal_type(literal_string_instance)  # revealed: LiteralString
-
-reveal_type(A() + literal_string_instance)  # revealed: A
-# TODO should be `A` since `str.__add__` doesn't support `A` instances
-# TODO overloads
-reveal_type(literal_string_instance + A())  # revealed: @Todo(return type)
-```
-
-## Operations involving instances of classes inheriting from `Any`
-
-`Any` and `Unknown` represent a set of possible runtime objects, wherein the bounds of the set are
-unknown. Whether the left-hand operand's dunder or the right-hand operand's reflected dunder depends
-on whether the right-hand operand is an instance of a class that is a subclass of the left-hand
-operand's class and overrides the reflected dunder. In the following example, because of the
-unknowable nature of `Any`/`Unknown`, we must consider both possibilities: `Any`/`Unknown` might
-resolve to an unknown third class that inherits from `X` and overrides `__radd__`; but it also might
-not. Thus, the correct answer here for the `reveal_type` is `int | Unknown`.
-
-```py
-from does_not_exist import Foo  # error: [unresolved-import]
-
-reveal_type(Foo)  # revealed: Unknown
-
-class X:
-    def __add__(self, other: object) -> int:
-        return 42
-
-class Y(Foo): ...
-
-# TODO: Should be `int | Unknown`; see above discussion.
-reveal_type(X() + Y())  # revealed: int
-```
-
-## Unsupported
-
-### Dunder as instance attribute
-
-The magic method must exist on the class, not just on the instance:
-
-```py
-def add_impl(self, other) -> int:
-    return 1
-
-class A:
-    def __init__(self):
-        self.__add__ = add_impl
-
-# error: [unsupported-operator] "Operator `+` is unsupported between objects of type `A` and `A`"
-# revealed: Unknown
-reveal_type(A() + A())
-```
-
-### Missing dunder
-
-```py
-class A: ...
-
-# error: [unsupported-operator]
-# revealed: Unknown
-reveal_type(A() + A())
-```
-
-### Wrong position
-
-A left-hand dunder method doesn't apply for the right-hand operand, or vice versa:
-
-```py
-class A:
-    def __add__(self, other) -> int: ...
-
-class B:
-    def __radd__(self, other) -> int: ...
-
-class C: ...
-
-# error: [unsupported-operator]
-# revealed: Unknown
-reveal_type(C() + A())
-
-# error: [unsupported-operator]
-# revealed: Unknown
-reveal_type(B() + C())
-```
-
-### Reflected dunder is not tried between two objects of the same type
-
-For the specific case where the left-hand operand is the exact same type as the right-hand operand,
-the reflected dunder of the right-hand operand is not tried; the runtime short-circuits after trying
-the unreflected dunder of the left-hand operand. For context, see
-[this mailing list discussion](https://mail.python.org/archives/list/python-dev@python.org/thread/7NZUCODEAPQFMRFXYRMGJXDSIS3WJYIV/).
-
-```py
-class Foo:
-    def __radd__(self, other: Foo) -> Foo:
-        return self
-
-# error: [unsupported-operator]
-# revealed: Unknown
-reveal_type(Foo() + Foo())
-```
-
-### Wrong type
-
-TODO: check signature and error if `other` is the wrong type

crates/red_knot_python_semantic/resources/mdtest/binary/integers.md

@@ -1,70 +0,0 @@
-# Binary operations on integers
-
-## Basic Arithmetic
-
-```py
-reveal_type(2 + 1)  # revealed: Literal[3]
-reveal_type(3 - 4)  # revealed: Literal[-1]
-reveal_type(3 * -1)  # revealed: Literal[-3]
-reveal_type(-3 // 3)  # revealed: Literal[-1]
-reveal_type(-3 / 3)  # revealed: float
-reveal_type(5 % 3)  # revealed: Literal[2]
-```
-
-## Power
-
-For power if the result fits in the int literal type it will be a Literal type. Otherwise the
-outcome is int.
-
-```py
-largest_u32 = 4_294_967_295
-reveal_type(2**2)  # revealed: Literal[4]
-reveal_type(1 ** (largest_u32 + 1))  # revealed: int
-reveal_type(2**largest_u32)  # revealed: int
-```
-
-## Division by Zero
-
-This error is really outside the current Python type system, because e.g. `int.__truediv__` and
-friends are not annotated to indicate that it's an error, and we don't even have a facility to
-permit such an annotation. So arguably divide-by-zero should be a lint error rather than a type
-checker error. But we choose to go ahead and error in the cases that are very likely to be an error:
-dividing something typed as `int` or `float` by something known to be `Literal[0]`.
-
-This isn't _definitely_ an error, because the object typed as `int` or `float` could be an instance
-of a custom subclass which overrides division behavior to handle zero without error. But if this
-unusual case occurs, the error can be avoided by explicitly typing the dividend as that safe custom
-subclass; we only emit the error if the LHS type is exactly `int` or `float`, not if its a subclass.
-
-```py
-a = 1 / 0  # error: "Cannot divide object of type `Literal[1]` by zero"
-reveal_type(a)  # revealed: float
-
-b = 2 // 0  # error: "Cannot floor divide object of type `Literal[2]` by zero"
-reveal_type(b)  # revealed: int
-
-c = 3 % 0  # error: "Cannot reduce object of type `Literal[3]` modulo zero"
-reveal_type(c)  # revealed: int
-
-# error: "Cannot divide object of type `int` by zero"
-# revealed: float
-reveal_type(int() / 0)
-
-# error: "Cannot divide object of type `Literal[1]` by zero"
-# revealed: float
-reveal_type(1 / False)
-# error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
-True / False
-# error: [division-by-zero] "Cannot divide object of type `Literal[True]` by zero"
-bool(1) / False
-
-# error: "Cannot divide object of type `float` by zero"
-# revealed: float
-reveal_type(1.0 / 0)
-
-class MyInt(int): ...
-
-# No error for a subclass of int
-# revealed: float
-reveal_type(MyInt(3) / 0)
-```

crates/red_knot_python_semantic/resources/mdtest/boolean/short_circuit.md

@@ -1,78 +0,0 @@
-# Short-Circuit Evaluation
-
-## Not all boolean expressions must be evaluated
-
-In `or` expressions, if the left-hand side is truthy, the right-hand side is not evaluated.
-Similarly, in `and` expressions, if the left-hand side is falsy, the right-hand side is not
-evaluated.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance() or (x := 1):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if bool_instance() and (x := 1):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## First expression is always evaluated
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if (x := 1) or bool_instance():
-    reveal_type(x)  # revealed: Literal[1]
-
-if (x := 1) and bool_instance():
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## Statically known truthiness
-
-```py
-if True or (x := 1):
-    # TODO: infer that the second arm is never executed, and raise `unresolved-reference`.
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if True and (x := 1):
-    # TODO: infer that the second arm is always executed, do not raise a diagnostic
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## Later expressions can always use variables from earlier expressions
-
-```py
-def bool_instance() -> bool:
-    return True
-
-bool_instance() or (x := 1) or reveal_type(x)  # revealed: Literal[1]
-
-# error: [unresolved-reference]
-bool_instance() or reveal_type(y) or (y := 1)  # revealed: Unknown
-```
-
-## Nested expressions
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance() or ((x := 1) and bool_instance()):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if ((y := 1) and bool_instance()) or bool_instance():
-    reveal_type(y)  # revealed: Literal[1]
-
-# error: [possibly-unresolved-reference]
-if (bool_instance() and (z := 1)) or reveal_type(z):  # revealed: Literal[1]
-    # error: [possibly-unresolved-reference]
-    reveal_type(z)  # revealed: Literal[1]
-```

crates/red_knot_python_semantic/resources/mdtest/call/callable_instance.md

@@ -1,75 +0,0 @@
-# Callable instance
-
-## Dunder call
-
-```py
-class Multiplier:
-    def __init__(self, factor: float):
-        self.factor = factor
-
-    def __call__(self, number: float) -> float:
-        return number * self.factor
-
-a = Multiplier(2.0)(3.0)
-reveal_type(a)  # revealed: float
-
-class Unit: ...
-
-b = Unit()(3.0)  # error: "Object of type `Unit` is not callable"
-reveal_type(b)  # revealed: Unknown
-```
-
-## Possibly unbound `__call__` method
-
-```py
-def flag() -> bool: ...
-
-class PossiblyNotCallable:
-    if flag():
-        def __call__(self) -> int: ...
-
-a = PossiblyNotCallable()
-result = a()  # error: "Object of type `PossiblyNotCallable` is not callable (possibly unbound `__call__` method)"
-reveal_type(result)  # revealed: int
-```
-
-## Possibly unbound callable
-
-```py
-def flag() -> bool: ...
-
-if flag():
-    class PossiblyUnbound:
-        def __call__(self) -> int: ...
-
-# error: [possibly-unresolved-reference]
-a = PossiblyUnbound()
-reveal_type(a())  # revealed: int
-```
-
-## Non-callable `__call__`
-
-```py
-class NonCallable:
-    __call__ = 1
-
-a = NonCallable()
-# error: "Object of type `NonCallable` is not callable"
-reveal_type(a())  # revealed: Unknown
-```
-
-## Possibly non-callable `__call__`
-
-```py
-def flag() -> bool: ...
-
-class NonCallable:
-    if flag():
-        __call__ = 1
-    else:
-        def __call__(self) -> int: ...
-
-a = NonCallable()
-# error: "Object of type `Literal[1] | Literal[__call__]` is not callable (due to union element `Literal[1]`)"
-reveal_type(a())  # revealed: Unknown | int
-```

crates/red_knot_python_semantic/resources/mdtest/call/constructor.md

@@ -1,7 +0,0 @@
-# Constructor
-
-```py
-class Foo: ...
-
-reveal_type(Foo())  # revealed: Foo
-```

crates/red_knot_python_semantic/resources/mdtest/call/function.md

@@ -1,70 +0,0 @@
-# Call expression
-
-## Simple
-
-```py
-def get_int() -> int:
-    return 42
-
-reveal_type(get_int())  # revealed: int
-```
-
-## Async
-
-```py
-async def get_int_async() -> int:
-    return 42
-
-# TODO: we don't yet support `types.CoroutineType`, should be generic `Coroutine[Any, Any, int]`
-reveal_type(get_int_async())  # revealed: @Todo(generic types.CoroutineType)
-```
-
-## Generic
-
-```py
-def get_int[T]() -> int:
-    return 42
-
-reveal_type(get_int())  # revealed: int
-```
-
-## Decorated
-
-```py
-from typing import Callable
-
-def foo() -> int:
-    return 42
-
-# TODO: This should be resolved once we understand `Callable` annotations
-# error: [annotation-with-invalid-expression]
-def decorator(func) -> Callable[[], int]:
-    return foo
-
-@decorator
-def bar() -> str:
-    return "bar"
-
-# TODO: should reveal `int`, as the decorator replaces `bar` with `foo`
-reveal_type(bar())  # revealed: @Todo(return type)
-```
-
-## Invalid callable
-
-```py
-nonsense = 123
-x = nonsense()  # error: "Object of type `Literal[123]` is not callable"
-```
-
-## Potentially unbound function
-
-```py
-def flag() -> bool: ...
-
-if flag():
-    def foo() -> int:
-        return 42
-
-# error: [possibly-unresolved-reference]
-reveal_type(foo())  # revealed: int
-```

crates/red_knot_python_semantic/resources/mdtest/call/union.md

@@ -1,104 +0,0 @@
-# Unions in calls
-
-## Union of return types
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-if flag:
-
-    def f() -> int:
-        return 1
-
-else:
-
-    def f() -> str:
-        return "foo"
-
-reveal_type(f())  # revealed: int | str
-```
-
-## Calling with an unknown union
-
-```py
-from nonexistent import f  # error: [unresolved-import] "Cannot resolve import `nonexistent`"
-
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-if flag:
-
-    def f() -> int:
-        return 1
-
-reveal_type(f())  # revealed: Unknown | int
-```
-
-## Non-callable elements in a union
-
-Calling a union with a non-callable element should emit a diagnostic.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-if flag:
-    f = 1
-else:
-
-    def f() -> int:
-        return 1
-
-x = f()  # error: "Object of type `Literal[1] | Literal[f]` is not callable (due to union element `Literal[1]`)"
-reveal_type(x)  # revealed: Unknown | int
-```
-
-## Multiple non-callable elements in a union
-
-Calling a union with multiple non-callable elements should mention all of them in the diagnostic.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-
-if flag:
-    f = 1
-elif flag2:
-    f = "foo"
-else:
-
-    def f() -> int:
-        return 1
-
-# error: "Object of type `Literal[1] | Literal["foo"] | Literal[f]` is not callable (due to union elements Literal[1], Literal["foo"])"
-# revealed: Unknown | int
-reveal_type(f())
-```
-
-## All non-callable union elements
-
-Calling a union with no callable elements can emit a simpler diagnostic.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-if flag:
-    f = 1
-else:
-    f = "foo"
-
-x = f()  # error: "Object of type `Literal[1] | Literal["foo"]` is not callable"
-reveal_type(x)  # revealed: Unknown
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/byte_literals.md

@@ -1,43 +0,0 @@
-# Comparison: Byte literals
-
-These tests assert that we infer precise `Literal` types for comparisons between objects inferred as
-having `Literal` bytes types:
-
-```py
-reveal_type(b"abc" == b"abc")  # revealed: Literal[True]
-reveal_type(b"abc" == b"ab")  # revealed: Literal[False]
-
-reveal_type(b"abc" != b"abc")  # revealed: Literal[False]
-reveal_type(b"abc" != b"ab")  # revealed: Literal[True]
-
-reveal_type(b"abc" < b"abd")  # revealed: Literal[True]
-reveal_type(b"abc" < b"abb")  # revealed: Literal[False]
-
-reveal_type(b"abc" <= b"abc")  # revealed: Literal[True]
-reveal_type(b"abc" <= b"abb")  # revealed: Literal[False]
-
-reveal_type(b"abc" > b"abd")  # revealed: Literal[False]
-reveal_type(b"abc" > b"abb")  # revealed: Literal[True]
-
-reveal_type(b"abc" >= b"abc")  # revealed: Literal[True]
-reveal_type(b"abc" >= b"abd")  # revealed: Literal[False]
-
-reveal_type(b"" in b"")  # revealed: Literal[True]
-reveal_type(b"" in b"abc")  # revealed: Literal[True]
-reveal_type(b"abc" in b"")  # revealed: Literal[False]
-reveal_type(b"ab" in b"abc")  # revealed: Literal[True]
-reveal_type(b"abc" in b"abc")  # revealed: Literal[True]
-reveal_type(b"d" in b"abc")  # revealed: Literal[False]
-reveal_type(b"ac" in b"abc")  # revealed: Literal[False]
-reveal_type(b"\x81\x82" in b"\x80\x81\x82")  # revealed: Literal[True]
-reveal_type(b"\x82\x83" in b"\x80\x81\x82")  # revealed: Literal[False]
-
-reveal_type(b"ab" not in b"abc")  # revealed: Literal[False]
-reveal_type(b"ac" not in b"abc")  # revealed: Literal[True]
-
-reveal_type(b"abc" is b"abc")  # revealed: bool
-reveal_type(b"abc" is b"ab")  # revealed: Literal[False]
-
-reveal_type(b"abc" is not b"abc")  # revealed: bool
-reveal_type(b"abc" is not b"ab")  # revealed: Literal[True]
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/identity.md

@@ -1,40 +0,0 @@
-# Identity tests
-
-```py
-class A: ...
-
-def get_a() -> A: ...
-def get_object() -> object: ...
-
-a1 = get_a()
-a2 = get_a()
-
-n1 = None
-n2 = None
-
-o = get_object()
-
-reveal_type(a1 is a1)  # revealed: bool
-reveal_type(a1 is a2)  # revealed: bool
-
-reveal_type(n1 is n1)  # revealed: Literal[True]
-reveal_type(n1 is n2)  # revealed: Literal[True]
-
-reveal_type(a1 is n1)  # revealed: Literal[False]
-reveal_type(n1 is a1)  # revealed: Literal[False]
-
-reveal_type(a1 is o)  # revealed: bool
-reveal_type(n1 is o)  # revealed: bool
-
-reveal_type(a1 is not a1)  # revealed: bool
-reveal_type(a1 is not a2)  # revealed: bool
-
-reveal_type(n1 is not n1)  # revealed: Literal[False]
-reveal_type(n1 is not n2)  # revealed: Literal[False]
-
-reveal_type(a1 is not n1)  # revealed: Literal[True]
-reveal_type(n1 is not a1)  # revealed: Literal[True]
-
-reveal_type(a1 is not o)  # revealed: bool
-reveal_type(n1 is not o)  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/instances/membership_test.md

@@ -1,160 +0,0 @@
-# Comparison: Membership Test
-
-In Python, the term "membership test operators" refers to the operators `in` and `not in`. To
-customize their behavior, classes can implement one of the special methods `__contains__`,
-`__iter__`, or `__getitem__`.
-
-For references, see:
-
-- <https://docs.python.org/3/reference/expressions.html#membership-test-details>
-- <https://docs.python.org/3/reference/datamodel.html#object.__contains__>
-- <https://snarky.ca/unravelling-membership-testing/>
-
-## Implements `__contains__`
-
-Classes can support membership tests by implementing the `__contains__` method:
-
-```py
-class A:
-    def __contains__(self, item: str) -> bool:
-        return True
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-# TODO: should emit diagnostic, need to check arg type, will fail
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Implements `__iter__`
-
-Classes that don't implement `__contains__`, but do implement `__iter__`, also support containment
-checks; the needle will be sought in their iterated items:
-
-```py
-class StringIterator:
-    def __next__(self) -> str:
-        return "foo"
-
-class A:
-    def __iter__(self) -> StringIterator:
-        return StringIterator()
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Implements `__getitems__`
-
-The final fallback is to implement `__getitem__` for integer keys. Python will call `__getitem__`
-with `0`, `1`, `2`... until either the needle is found (leading the membership test to evaluate to
-`True`) or `__getitem__` raises `IndexError` (the raised exception is swallowed, but results in the
-membership test evaluating to `False`).
-
-```py
-class A:
-    def __getitem__(self, key: int) -> str:
-        return "foo"
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Wrong Return Type
-
-Python coerces the results of containment checks to `bool`, even if `__contains__` returns a
-non-bool:
-
-```py
-class A:
-    def __contains__(self, item: str) -> str:
-        return "foo"
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-```
-
-## Literal Result for `in` and `not in`
-
-`__contains__` with a literal return type may result in a `BooleanLiteral` outcome.
-
-```py
-from typing import Literal
-
-class AlwaysTrue:
-    def __contains__(self, item: int) -> Literal[1]:
-        return 1
-
-class AlwaysFalse:
-    def __contains__(self, item: int) -> Literal[""]:
-        return ""
-
-reveal_type(42 in AlwaysTrue())  # revealed: Literal[True]
-reveal_type(42 not in AlwaysTrue())  # revealed: Literal[False]
-
-reveal_type(42 in AlwaysFalse())  # revealed: Literal[False]
-reveal_type(42 not in AlwaysFalse())  # revealed: Literal[True]
-```
-
-## No Fallback for `__contains__`
-
-If `__contains__` is implemented, checking membership of a type it doesn't accept is an error; it
-doesn't result in a fallback to `__iter__` or `__getitem__`:
-
-```py
-class CheckContains: ...
-class CheckIter: ...
-class CheckGetItem: ...
-
-class CheckIterIterator:
-    def __next__(self) -> CheckIter:
-        return CheckIter()
-
-class A:
-    def __contains__(self, item: CheckContains) -> bool:
-        return True
-
-    def __iter__(self) -> CheckIterIterator:
-        return CheckIterIterator()
-
-    def __getitem__(self, key: int) -> CheckGetItem:
-        return CheckGetItem()
-
-reveal_type(CheckContains() in A())  # revealed: bool
-
-# TODO: should emit diagnostic, need to check arg type,
-# should not fall back to __iter__ or __getitem__
-reveal_type(CheckIter() in A())  # revealed: bool
-reveal_type(CheckGetItem() in A())  # revealed: bool
-
-class B:
-    def __iter__(self) -> CheckIterIterator:
-        return CheckIterIterator()
-
-    def __getitem__(self, key: int) -> CheckGetItem:
-        return CheckGetItem()
-
-reveal_type(CheckIter() in B())  # revealed: bool
-# Always use `__iter__`, regardless of iterated type; there's no NotImplemented
-# in this case, so there's no fallback to `__getitem__`
-reveal_type(CheckGetItem() in B())  # revealed: bool
-```
-
-## Invalid Old-Style Iteration
-
-If `__getitem__` is implemented but does not accept integer arguments, then the membership test is
-not supported and should trigger a diagnostic.
-
-```py
-class A:
-    def __getitem__(self, key: str) -> str:
-        return "foo"
-
-# TODO should emit a diagnostic
-reveal_type(42 in A())  # revealed: bool
-reveal_type("hello" in A())  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/instances/rich_comparison.md

@@ -1,328 +0,0 @@
-# Comparison: Rich Comparison
-
-Rich comparison operations (`==`, `!=`, `<`, `<=`, `>`, `>=`) in Python are implemented through
-double-underscore methods that allow customization of comparison behavior.
-
-For references, see:
-
-- <https://docs.python.org/3/reference/datamodel.html#object.__lt__>
-- <https://snarky.ca/unravelling-rich-comparison-operators/>
-
-## Rich Comparison Dunder Implementations For Same Class
-
-Classes can support rich comparison by implementing dunder methods like `__eq__`, `__ne__`, etc. The
-most common case involves implementing these methods for the same type:
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: A) -> int:
-        return 42
-
-    def __ne__(self, other: A) -> float:
-        return 42.0
-
-    def __lt__(self, other: A) -> str:
-        return "42"
-
-    def __le__(self, other: A) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: A) -> list:
-        return [42]
-
-    def __ge__(self, other: A) -> set:
-        return {42}
-
-reveal_type(A() == A())  # revealed: int
-reveal_type(A() != A())  # revealed: float
-reveal_type(A() < A())  # revealed: str
-reveal_type(A() <= A())  # revealed: bytes
-reveal_type(A() > A())  # revealed: list
-reveal_type(A() >= A())  # revealed: set
-```
-
-## Rich Comparison Dunder Implementations for Other Class
-
-In some cases, classes may implement rich comparison dunder methods for comparisons with a different
-type:
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: B) -> int:
-        return 42
-
-    def __ne__(self, other: B) -> float:
-        return 42.0
-
-    def __lt__(self, other: B) -> str:
-        return "42"
-
-    def __le__(self, other: B) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: B) -> list:
-        return [42]
-
-    def __ge__(self, other: B) -> set:
-        return {42}
-
-class B: ...
-
-reveal_type(A() == B())  # revealed: int
-reveal_type(A() != B())  # revealed: float
-reveal_type(A() < B())  # revealed: str
-reveal_type(A() <= B())  # revealed: bytes
-reveal_type(A() > B())  # revealed: list
-reveal_type(A() >= B())  # revealed: set
-```
-
-## Reflected Comparisons
-
-Fallback to the right-hand side’s comparison methods occurs when the left-hand side does not define
-them. Note: class `B` has its own `__eq__` and `__ne__` methods to override those of `object`, but
-these methods will be ignored here because they require a mismatched operand type.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: B) -> int:
-        return 42
-
-    def __ne__(self, other: B) -> float:
-        return 42.0
-
-    def __lt__(self, other: B) -> str:
-        return "42"
-
-    def __le__(self, other: B) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: B) -> list:
-        return [42]
-
-    def __ge__(self, other: B) -> set:
-        return {42}
-
-class B:
-    # To override builtins.object.__eq__ and builtins.object.__ne__
-    # TODO these should emit an invalid override diagnostic
-    def __eq__(self, other: str) -> B:
-        return B()
-
-    def __ne__(self, other: str) -> B:
-        return B()
-
-# TODO: should be `int` and `float`.
-# Need to check arg type and fall back to `rhs.__eq__` and `rhs.__ne__`.
-#
-# Because `object.__eq__` and `object.__ne__` accept `object` in typeshed,
-# this can only happen with an invalid override of these methods,
-# but we still support it.
-reveal_type(B() == A())  # revealed: B
-reveal_type(B() != A())  # revealed: B
-
-reveal_type(B() < A())  # revealed: list
-reveal_type(B() <= A())  # revealed: set
-
-reveal_type(B() > A())  # revealed: str
-reveal_type(B() >= A())  # revealed: bytes
-
-class C:
-    def __gt__(self, other: C) -> int:
-        return 42
-
-    def __ge__(self, other: C) -> float:
-        return 42.0
-
-reveal_type(C() < C())  # revealed: int
-reveal_type(C() <= C())  # revealed: float
-```
-
-## Reflected Comparisons with Subclasses
-
-When subclasses override comparison methods, these overridden methods take precedence over those in
-the parent class. Class `B` inherits from `A` and redefines comparison methods to return types other
-than `A`.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: A) -> A:
-        return A()
-
-    def __ne__(self, other: A) -> A:
-        return A()
-
-    def __lt__(self, other: A) -> A:
-        return A()
-
-    def __le__(self, other: A) -> A:
-        return A()
-
-    def __gt__(self, other: A) -> A:
-        return A()
-
-    def __ge__(self, other: A) -> A:
-        return A()
-
-class B(A):
-    def __eq__(self, other: A) -> int:
-        return 42
-
-    def __ne__(self, other: A) -> float:
-        return 42.0
-
-    def __lt__(self, other: A) -> str:
-        return "42"
-
-    def __le__(self, other: A) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: A) -> list:
-        return [42]
-
-    def __ge__(self, other: A) -> set:
-        return {42}
-
-reveal_type(A() == B())  # revealed: int
-reveal_type(A() != B())  # revealed: float
-
-reveal_type(A() < B())  # revealed: list
-reveal_type(A() <= B())  # revealed: set
-
-reveal_type(A() > B())  # revealed: str
-reveal_type(A() >= B())  # revealed: bytes
-```
-
-## Reflected Comparisons with Subclass But Falls Back to LHS
-
-In the case of a subclass, the right-hand side has priority. However, if the overridden dunder
-method has an mismatched type to operand, the comparison will fall back to the left-hand side.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __lt__(self, other: A) -> A:
-        return A()
-
-    def __gt__(self, other: A) -> A:
-        return A()
-
-class B(A):
-    def __lt__(self, other: int) -> B:
-        return B()
-
-    def __gt__(self, other: int) -> B:
-        return B()
-
-# TODO: should be `A`, need to check argument type and fall back to LHS method
-reveal_type(A() < B())  # revealed: B
-reveal_type(A() > B())  # revealed: B
-```
-
-## Operations involving instances of classes inheriting from `Any`
-
-`Any` and `Unknown` represent a set of possible runtime objects, wherein the bounds of the set are
-unknown. Whether the left-hand operand's dunder or the right-hand operand's reflected dunder depends
-on whether the right-hand operand is an instance of a class that is a subclass of the left-hand
-operand's class and overrides the reflected dunder. In the following example, because of the
-unknowable nature of `Any`/`Unknown`, we must consider both possibilities: `Any`/`Unknown` might
-resolve to an unknown third class that inherits from `X` and overrides `__gt__`; but it also might
-not. Thus, the correct answer here for the `reveal_type` is `int | Unknown`.
-
-(This test is referenced from `mdtest/binary/instances.md`)
-
-```py
-from does_not_exist import Foo  # error: [unresolved-import]
-
-reveal_type(Foo)  # revealed: Unknown
-
-class X:
-    def __lt__(self, other: object) -> int:
-        return 42
-
-class Y(Foo): ...
-
-# TODO: Should be `int | Unknown`; see above discussion.
-reveal_type(X() < Y())  # revealed: int
-```
-
-## Equality and Inequality Fallback
-
-This test confirms that `==` and `!=` comparisons default to identity comparisons (`is`, `is not`)
-when argument types do not match the method signature.
-
-Please refer to the [docs](https://docs.python.org/3/reference/datamodel.html#object.__eq__)
-
-```py
-from __future__ import annotations
-
-class A:
-    # TODO both these overrides should emit invalid-override diagnostic
-    def __eq__(self, other: int) -> A:
-        return A()
-
-    def __ne__(self, other: int) -> A:
-        return A()
-
-# TODO: it should be `bool`, need to check arg type and fall back to `is` and `is not`
-reveal_type(A() == A())  # revealed: A
-reveal_type(A() != A())  # revealed: A
-```
-
-## Object Comparisons with Typeshed
-
-```py
-class A: ...
-
-reveal_type(A() == object())  # revealed: bool
-reveal_type(A() != object())  # revealed: bool
-reveal_type(object() == A())  # revealed: bool
-reveal_type(object() != A())  # revealed: bool
-
-# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `object`"
-# revealed: Unknown
-reveal_type(A() < object())
-```
-
-## Numbers Comparison with typeshed
-
-```py
-reveal_type(1 == 1.0)  # revealed: bool
-reveal_type(1 != 1.0)  # revealed: bool
-reveal_type(1 < 1.0)  # revealed: bool
-reveal_type(1 <= 1.0)  # revealed: bool
-reveal_type(1 > 1.0)  # revealed: bool
-reveal_type(1 >= 1.0)  # revealed: bool
-
-reveal_type(1 == 2j)  # revealed: bool
-reveal_type(1 != 2j)  # revealed: bool
-
-# TODO: should be Unknown and emit diagnostic,
-# need to check arg type and should be failed
-reveal_type(1 < 2j)  # revealed: bool
-reveal_type(1 <= 2j)  # revealed: bool
-reveal_type(1 > 2j)  # revealed: bool
-reveal_type(1 >= 2j)  # revealed: bool
-
-def bool_instance() -> bool:
-    return True
-
-def int_instance() -> int:
-    return 42
-
-x = bool_instance()
-y = int_instance()
-
-reveal_type(x < y)  # revealed: bool
-reveal_type(y < x)  # revealed: bool
-reveal_type(4.2 < x)  # revealed: bool
-reveal_type(x < 4.2)  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/integers.md

@@ -1,29 +0,0 @@
-# Comparison: Integers
-
-## Integer literals
-
-```py
-reveal_type(1 == 1 == True)  # revealed: Literal[True]
-reveal_type(1 == 1 == 2 == 4)  # revealed: Literal[False]
-reveal_type(False < True <= 2 < 3 != 6)  # revealed: Literal[True]
-reveal_type(1 < 1)  # revealed: Literal[False]
-reveal_type(1 > 1)  # revealed: Literal[False]
-reveal_type(1 is 1)  # revealed: bool
-reveal_type(1 is not 1)  # revealed: bool
-reveal_type(1 is 2)  # revealed: Literal[False]
-reveal_type(1 is not 7)  # revealed: Literal[True]
-# TODO: should be Unknown, and emit diagnostic, once we check call argument types
-reveal_type(1 <= "" and 0 < 1)  # revealed: bool
-```
-
-## Integer instance
-
-```py
-# TODO: implement lookup of `__eq__` on typeshed `int` stub.
-def int_instance() -> int:
-    return 42
-
-reveal_type(1 == int_instance())  # revealed: bool
-reveal_type(9 < int_instance())  # revealed: bool
-reveal_type(int_instance() < int_instance())  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/intersections.md

@@ -1,155 +0,0 @@
-# Comparison: Intersections
-
-## Positive contributions
-
-If we have an intersection type `A & B` and we get a definitive true/false answer for one of the
-types, we can infer that the result for the intersection type is also true/false:
-
-```py
-class Base: ...
-
-class Child1(Base):
-    def __eq__(self, other) -> Literal[True]:
-        return True
-
-class Child2(Base): ...
-
-def get_base() -> Base: ...
-
-x = get_base()
-c1 = Child1()
-
-# Create an intersection type through narrowing:
-if isinstance(x, Child1):
-    if isinstance(x, Child2):
-        reveal_type(x)  # revealed: Child1 & Child2
-
-        reveal_type(x == 1)  # revealed: Literal[True]
-
-        # Other comparison operators fall back to the base type:
-        reveal_type(x > 1)  # revealed: bool
-        reveal_type(x is c1)  # revealed: bool
-```
-
-## Negative contributions
-
-Negative contributions to the intersection type only allow simplifications in a few special cases
-(equality and identity comparisons).
-
-### Equality comparisons
-
-#### Literal strings
-
-```py
-x = "x" * 1_000_000_000
-y = "y" * 1_000_000_000
-reveal_type(x)  # revealed: LiteralString
-
-if x != "abc":
-    reveal_type(x)  # revealed: LiteralString & ~Literal["abc"]
-
-    reveal_type(x == "abc")  # revealed: Literal[False]
-    reveal_type("abc" == x)  # revealed: Literal[False]
-    reveal_type(x == "something else")  # revealed: bool
-    reveal_type("something else" == x)  # revealed: bool
-
-    reveal_type(x != "abc")  # revealed: Literal[True]
-    reveal_type("abc" != x)  # revealed: Literal[True]
-    reveal_type(x != "something else")  # revealed: bool
-    reveal_type("something else" != x)  # revealed: bool
-
-    reveal_type(x == y)  # revealed: bool
-    reveal_type(y == x)  # revealed: bool
-    reveal_type(x != y)  # revealed: bool
-    reveal_type(y != x)  # revealed: bool
-
-    reveal_type(x >= "abc")  # revealed: bool
-    reveal_type("abc" >= x)  # revealed: bool
-
-    reveal_type(x in "abc")  # revealed: bool
-    reveal_type("abc" in x)  # revealed: bool
-```
-
-#### Integers
-
-```py
-def get_int() -> int: ...
-
-x = get_int()
-
-if x != 1:
-    reveal_type(x)  # revealed: int & ~Literal[1]
-
-    reveal_type(x != 1)  # revealed: Literal[True]
-    reveal_type(x != 2)  # revealed: bool
-
-    reveal_type(x == 1)  # revealed: Literal[False]
-    reveal_type(x == 2)  # revealed: bool
-```
-
-### Identity comparisons
-
-```py
-class A: ...
-
-def get_object() -> object: ...
-
-o = object()
-
-a = A()
-n = None
-
-if o is not None:
-    reveal_type(o)  # revealed: object & ~None
-
-    reveal_type(o is n)  # revealed: Literal[False]
-    reveal_type(o is not n)  # revealed: Literal[True]
-```
-
-## Diagnostics
-
-### Unsupported operators for positive contributions
-
-Raise an error if any of the positive contributions to the intersection type are unsupported for the
-given operator:
-
-```py
-class Container:
-    def __contains__(self, x) -> bool: ...
-
-class NonContainer: ...
-
-def get_object() -> object: ...
-
-x = get_object()
-
-if isinstance(x, Container):
-    if isinstance(x, NonContainer):
-        reveal_type(x)  # revealed: Container & NonContainer
-
-        # error: [unsupported-operator] "Operator `in` is not supported for types `int` and `NonContainer`"
-        reveal_type(2 in x)  # revealed: bool
-```
-
-### Unsupported operators for negative contributions
-
-Do *not* raise an error if any of the negative contributions to the intersection type are
-unsupported for the given operator:
-
-```py
-class Container:
-    def __contains__(self, x) -> bool: ...
-
-class NonContainer: ...
-
-def get_object() -> object: ...
-
-x = get_object()
-
-if isinstance(x, Container):
-    if not isinstance(x, NonContainer):
-        reveal_type(x)  # revealed: Container & ~NonContainer
-
-        # No error here!
-        reveal_type(2 in x)  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/non_bool_returns.md

@@ -1,41 +0,0 @@
-# Comparison: Non boolean returns
-
-Walking through examples:
-
-- `a = A() < B() < C()`
-
-    1. `A() < B() and B() < C()` - split in N comparison
-    1. `A()` and `B()` - evaluate outcome types
-    1. `bool` and `bool` - evaluate truthiness
-    1. `A | B` - union of "first true" types
-
-- `b = 0 < 1 < A() < 3`
-
-    1. `0 < 1 and 1 < A() and A() < 3` - split in N comparison
-    1. `True` and `bool` and `A` - evaluate outcome types
-    1. `True` and `bool` and `bool` - evaluate truthiness
-    1. `bool | A` - union of "true" types
-
-- `c = 10 < 0 < A() < B() < C()` short-circuit to False
-
-```py
-from __future__ import annotations
-
-class A:
-    def __lt__(self, other) -> A: ...
-
-class B:
-    def __lt__(self, other) -> B: ...
-
-class C:
-    def __lt__(self, other) -> C: ...
-
-x = A() < B() < C()
-reveal_type(x)  # revealed: A | B
-
-y = 0 < 1 < A() < 3
-reveal_type(y)  # revealed: bool | A
-
-z = 10 < 0 < A() < B() < C()
-reveal_type(z)  # revealed: Literal[False]
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/strings.md

@@ -1,20 +0,0 @@
-# Comparison: Strings
-
-## String literals
-
-```py
-def str_instance() -> str: ...
-
-reveal_type("abc" == "abc")  # revealed: Literal[True]
-reveal_type("ab_cd" <= "ab_ce")  # revealed: Literal[True]
-reveal_type("abc" in "ab cd")  # revealed: Literal[False]
-reveal_type("" not in "hello")  # revealed: Literal[False]
-reveal_type("--" is "--")  # revealed: bool
-reveal_type("A" is "B")  # revealed: Literal[False]
-reveal_type("--" is not "--")  # revealed: bool
-reveal_type("A" is not "B")  # revealed: Literal[True]
-reveal_type(str_instance() < "...")  # revealed: bool
-
-# ensure we're not comparing the interned salsa symbols, which compare by order of declaration.
-reveal_type("ab" < "ab_cd")  # revealed: Literal[True]
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/tuples.md

@@ -1,341 +0,0 @@
-# Comparison: Tuples
-
-## Heterogeneous
-
-For tuples like `tuple[int, str, Literal[1]]`
-
-### Value Comparisons
-
-"Value Comparisons" refers to the operators: `==`, `!=`, `<`, `<=`, `>`, `>=`
-
-#### Results without Ambiguity
-
-Cases where the result can be definitively inferred as a `BooleanLiteral`.
-
-```py
-a = (1, "test", (3, 13), True)
-b = (1, "test", (3, 14), False)
-
-reveal_type(a == a)  # revealed: Literal[True]
-reveal_type(a != a)  # revealed: Literal[False]
-reveal_type(a < a)  # revealed: Literal[False]
-reveal_type(a <= a)  # revealed: Literal[True]
-reveal_type(a > a)  # revealed: Literal[False]
-reveal_type(a >= a)  # revealed: Literal[True]
-
-reveal_type(a == b)  # revealed: Literal[False]
-reveal_type(a != b)  # revealed: Literal[True]
-reveal_type(a < b)  # revealed: Literal[True]
-reveal_type(a <= b)  # revealed: Literal[True]
-reveal_type(a > b)  # revealed: Literal[False]
-reveal_type(a >= b)  # revealed: Literal[False]
-```
-
-Even when tuples have different lengths, comparisons should be handled appropriately.
-
-```py path=different_length.py
-a = (1, 2, 3)
-b = (1, 2, 3, 4)
-
-reveal_type(a == b)  # revealed: Literal[False]
-reveal_type(a != b)  # revealed: Literal[True]
-reveal_type(a < b)  # revealed: Literal[True]
-reveal_type(a <= b)  # revealed: Literal[True]
-reveal_type(a > b)  # revealed: Literal[False]
-reveal_type(a >= b)  # revealed: Literal[False]
-
-c = ("a", "b", "c", "d")
-d = ("a", "b", "c")
-
-reveal_type(c == d)  # revealed: Literal[False]
-reveal_type(c != d)  # revealed: Literal[True]
-reveal_type(c < d)  # revealed: Literal[False]
-reveal_type(c <= d)  # revealed: Literal[False]
-reveal_type(c > d)  # revealed: Literal[True]
-reveal_type(c >= d)  # revealed: Literal[True]
-```
-
-#### Results with Ambiguity
-
-```py
-def bool_instance() -> bool:
-    return True
-
-def int_instance() -> int:
-    return 42
-
-a = (bool_instance(),)
-b = (int_instance(),)
-
-reveal_type(a == a)  # revealed: bool
-reveal_type(a != a)  # revealed: bool
-reveal_type(a < a)  # revealed: bool
-reveal_type(a <= a)  # revealed: bool
-reveal_type(a > a)  # revealed: bool
-reveal_type(a >= a)  # revealed: bool
-
-reveal_type(a == b)  # revealed: bool
-reveal_type(a != b)  # revealed: bool
-reveal_type(a < b)  # revealed: bool
-reveal_type(a <= b)  # revealed: bool
-reveal_type(a > b)  # revealed: bool
-reveal_type(a >= b)  # revealed: bool
-```
-
-#### Comparison Unsupported
-
-If two tuples contain types that do not support comparison, the result may be `Unknown`. However,
-`==` and `!=` are exceptions and can still provide definite results.
-
-```py
-a = (1, 2)
-b = (1, "hello")
-
-# TODO: should be Literal[False], once we implement (in)equality for mismatched literals
-reveal_type(a == b)  # revealed: bool
-
-# TODO: should be Literal[True], once we implement (in)equality for mismatched literals
-reveal_type(a != b)  # revealed: bool
-
-# TODO: should be Unknown and add more informative diagnostics
-reveal_type(a < b)  # revealed: bool
-reveal_type(a <= b)  # revealed: bool
-reveal_type(a > b)  # revealed: bool
-reveal_type(a >= b)  # revealed: bool
-```
-
-However, if the lexicographic comparison completes without reaching a point where str and int are
-compared, Python will still produce a result based on the prior elements.
-
-```py path=short_circuit.py
-a = (1, 2)
-b = (999999, "hello")
-
-reveal_type(a == b)  # revealed: Literal[False]
-reveal_type(a != b)  # revealed: Literal[True]
-reveal_type(a < b)  # revealed: Literal[True]
-reveal_type(a <= b)  # revealed: Literal[True]
-reveal_type(a > b)  # revealed: Literal[False]
-reveal_type(a >= b)  # revealed: Literal[False]
-```
-
-#### Matryoshka Tuples
-
-```py
-a = (1, True, "Hello")
-b = (a, a, a)
-c = (b, b, b)
-
-reveal_type(c == c)  # revealed: Literal[True]
-reveal_type(c != c)  # revealed: Literal[False]
-reveal_type(c < c)  # revealed: Literal[False]
-reveal_type(c <= c)  # revealed: Literal[True]
-reveal_type(c > c)  # revealed: Literal[False]
-reveal_type(c >= c)  # revealed: Literal[True]
-```
-
-#### Non Boolean Rich Comparisons
-
-Rich comparison methods defined in a class affect tuple comparisons as well. Proper type inference
-should be possible even in cases where these methods return non-boolean types.
-
-Note: Tuples use lexicographic comparisons. If the `==` result for all paired elements in the tuple
-is True, the comparison then considers the tuple’s length. Regardless of the return type of the
-dunder methods, the final result can still be a boolean value.
-
-(+cpython: For tuples, `==` and `!=` always produce boolean results, regardless of the return type
-of the dunder methods.)
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, o: object) -> str:
-        return "hello"
-
-    def __ne__(self, o: object) -> bytes:
-        return b"world"
-
-    def __lt__(self, o: A) -> float:
-        return 3.14
-
-    def __le__(self, o: A) -> complex:
-        return complex(0.5, -0.5)
-
-    def __gt__(self, o: A) -> tuple:
-        return (1, 2, 3)
-
-    def __ge__(self, o: A) -> list:
-        return [1, 2, 3]
-
-a = (A(), A())
-
-reveal_type(a == a)  # revealed: bool
-reveal_type(a != a)  # revealed: bool
-reveal_type(a < a)  # revealed: float | Literal[False]
-reveal_type(a <= a)  # revealed: complex | Literal[True]
-reveal_type(a > a)  # revealed: tuple | Literal[False]
-reveal_type(a >= a)  # revealed: list | Literal[True]
-
-# If lexicographic comparison is finished before comparing A()
-b = ("1_foo", A())
-c = ("2_bar", A())
-
-reveal_type(b == c)  # revealed: Literal[False]
-reveal_type(b != c)  # revealed: Literal[True]
-reveal_type(b < c)  # revealed: Literal[True]
-reveal_type(b <= c)  # revealed: Literal[True]
-reveal_type(b > c)  # revealed: Literal[False]
-reveal_type(b >= c)  # revealed: Literal[False]
-
-class B:
-    def __lt__(self, o: B) -> set:
-        return set()
-
-reveal_type((A(), B()) < (A(), B()))  # revealed: float | set | Literal[False]
-```
-
-#### Special Handling of Eq and NotEq in Lexicographic Comparisons
-
-> Example: `(int_instance(), "foo") == (int_instance(), "bar")`
-
-`Eq` and `NotEq` have unique behavior compared to other operators in lexicographic comparisons.
-Specifically, for `Eq`, if any non-equal pair exists within the tuples being compared, we can
-immediately conclude that the tuples are not equal. Conversely, for `NotEq`, if any non-equal pair
-exists, we can determine that the tuples are unequal.
-
-In contrast, with operators like `<` and `>`, the comparison must consider each pair of elements
-sequentially, and the final outcome might remain ambiguous until all pairs are compared.
-
-```py
-def str_instance() -> str:
-    return "hello"
-
-def int_instance() -> int:
-    return 42
-
-reveal_type("foo" == "bar")  # revealed: Literal[False]
-reveal_type(("foo",) == ("bar",))  # revealed: Literal[False]
-reveal_type((4, "foo") == (4, "bar"))  # revealed: Literal[False]
-reveal_type((int_instance(), "foo") == (int_instance(), "bar"))  # revealed: Literal[False]
-
-a = (str_instance(), int_instance(), "foo")
-
-reveal_type(a == a)  # revealed: bool
-reveal_type(a != a)  # revealed: bool
-reveal_type(a < a)  # revealed: bool
-reveal_type(a <= a)  # revealed: bool
-reveal_type(a > a)  # revealed: bool
-reveal_type(a >= a)  # revealed: bool
-
-b = (str_instance(), int_instance(), "bar")
-
-reveal_type(a == b)  # revealed: Literal[False]
-reveal_type(a != b)  # revealed: Literal[True]
-reveal_type(a < b)  # revealed: bool
-reveal_type(a <= b)  # revealed: bool
-reveal_type(a > b)  # revealed: bool
-reveal_type(a >= b)  # revealed: bool
-
-c = (str_instance(), int_instance(), "foo", "different_length")
-reveal_type(a == c)  # revealed: Literal[False]
-reveal_type(a != c)  # revealed: Literal[True]
-reveal_type(a < c)  # revealed: bool
-reveal_type(a <= c)  # revealed: bool
-reveal_type(a > c)  # revealed: bool
-reveal_type(a >= c)  # revealed: bool
-```
-
-#### Error Propagation
-
-Errors occurring within a tuple comparison should propagate outward. However, if the tuple
-comparison can clearly conclude before encountering an error, the error should not be raised.
-
-```py
-def int_instance() -> int:
-    return 42
-
-def str_instance() -> str:
-    return "hello"
-
-class A: ...
-
-# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`"
-A() < A()
-# error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`"
-A() <= A()
-# error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`"
-A() > A()
-# error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`"
-A() >= A()
-
-a = (0, int_instance(), A())
-
-# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-reveal_type(a < a)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-reveal_type(a <= a)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-reveal_type(a > a)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-reveal_type(a >= a)  # revealed: Unknown
-
-# Comparison between `a` and `b` should only involve the first elements, `Literal[0]` and `Literal[99999]`,
-# and should terminate immediately.
-b = (99999, int_instance(), A())
-
-reveal_type(a < b)  # revealed: Literal[True]
-reveal_type(a <= b)  # revealed: Literal[True]
-reveal_type(a > b)  # revealed: Literal[False]
-reveal_type(a >= b)  # revealed: Literal[False]
-```
-
-### Membership Test Comparisons
-
-"Membership Test Comparisons" refers to the operators `in` and `not in`.
-
-```py
-def int_instance() -> int:
-    return 42
-
-a = (1, 2)
-b = ((3, 4), (1, 2))
-c = ((1, 2, 3), (4, 5, 6))
-d = ((int_instance(), int_instance()), (int_instance(), int_instance()))
-
-reveal_type(a in b)  # revealed: Literal[True]
-reveal_type(a not in b)  # revealed: Literal[False]
-
-reveal_type(a in c)  # revealed: Literal[False]
-reveal_type(a not in c)  # revealed: Literal[True]
-
-reveal_type(a in d)  # revealed: bool
-reveal_type(a not in d)  # revealed: bool
-```
-
-### Identity Comparisons
-
-"Identity Comparisons" refers to `is` and `is not`.
-
-```py
-a = (1, 2)
-b = ("a", "b")
-c = (1, 2, 3)
-
-reveal_type(a is (1, 2))  # revealed: bool
-reveal_type(a is not (1, 2))  # revealed: bool
-
-# TODO should be Literal[False] once we implement comparison of mismatched literal types
-reveal_type(a is b)  # revealed: bool
-# TODO should be Literal[True] once we implement comparison of mismatched literal types
-reveal_type(a is not b)  # revealed: bool
-
-reveal_type(a is c)  # revealed: Literal[False]
-reveal_type(a is not c)  # revealed: Literal[True]
-```
-
-## Homogeneous
-
-For tuples like `tuple[int, ...]`, `tuple[Any, ...]`
-
-// TODO

crates/red_knot_python_semantic/resources/mdtest/comparison/unions.md

@@ -1,88 +0,0 @@
-# Comparison: Unions
-
-## Union on one side of the comparison
-
-Comparisons on union types need to consider all possible cases:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-one_or_two = 1 if flag else 2
-
-reveal_type(one_or_two <= 2)  # revealed: Literal[True]
-reveal_type(one_or_two <= 1)  # revealed: bool
-reveal_type(one_or_two <= 0)  # revealed: Literal[False]
-
-reveal_type(2 >= one_or_two)  # revealed: Literal[True]
-reveal_type(1 >= one_or_two)  # revealed: bool
-reveal_type(0 >= one_or_two)  # revealed: Literal[False]
-
-reveal_type(one_or_two < 1)  # revealed: Literal[False]
-reveal_type(one_or_two < 2)  # revealed: bool
-reveal_type(one_or_two < 3)  # revealed: Literal[True]
-
-reveal_type(one_or_two > 0)  # revealed: Literal[True]
-reveal_type(one_or_two > 1)  # revealed: bool
-reveal_type(one_or_two > 2)  # revealed: Literal[False]
-
-reveal_type(one_or_two == 3)  # revealed: Literal[False]
-reveal_type(one_or_two == 1)  # revealed: bool
-
-reveal_type(one_or_two != 3)  # revealed: Literal[True]
-reveal_type(one_or_two != 1)  # revealed: bool
-
-a_or_ab = "a" if flag else "ab"
-
-reveal_type(a_or_ab in "ab")  # revealed: Literal[True]
-reveal_type("a" in a_or_ab)  # revealed: Literal[True]
-
-reveal_type("c" not in a_or_ab)  # revealed: Literal[True]
-reveal_type("a" not in a_or_ab)  # revealed: Literal[False]
-
-reveal_type("b" in a_or_ab)  # revealed: bool
-reveal_type("b" not in a_or_ab)  # revealed: bool
-
-one_or_none = 1 if flag else None
-
-reveal_type(one_or_none is None)  # revealed: bool
-reveal_type(one_or_none is not None)  # revealed: bool
-```
-
-## Union on both sides of the comparison
-
-With unions on both sides, we need to consider the full cross product of options when building the
-resulting (union) type:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag_s, flag_l = bool_instance(), bool_instance()
-small = 1 if flag_s else 2
-large = 2 if flag_l else 3
-
-reveal_type(small <= large)  # revealed: Literal[True]
-reveal_type(small >= large)  # revealed: bool
-
-reveal_type(small < large)  # revealed: bool
-reveal_type(small > large)  # revealed: Literal[False]
-```
-
-## Unsupported operations
-
-Make sure we emit a diagnostic if *any* of the possible comparisons is unsupported. For now, we fall
-back to `bool` for the result type instead of trying to infer something more precise from the other
-(supported) variants:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-x = [1, 2] if flag else 1
-
-result = 1 in x  # error: "Operator `in` is not supported"
-reveal_type(result)  # revealed: bool
-```

crates/red_knot_python_semantic/resources/mdtest/comparison/unsupported.md

@@ -1,42 +0,0 @@
-# Comparison: Unsupported operators
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-a = 1 in 7  # error: "Operator `in` is not supported for types `Literal[1]` and `Literal[7]`"
-reveal_type(a)  # revealed: bool
-
-b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
-reveal_type(b)  # revealed: bool
-
-# TODO: should error, once operand type check is implemented
-# ("Operator `<` is not supported for types `object` and `int`")
-c = object() < 5
-# TODO: should be Unknown, once operand type check is implemented
-reveal_type(c)  # revealed: bool
-
-# TODO: should error, once operand type check is implemented
-# ("Operator `<` is not supported for types `int` and `object`")
-d = 5 < object()
-# TODO: should be Unknown, once operand type check is implemented
-reveal_type(d)  # revealed: bool
-
-flag = bool_instance()
-int_literal_or_str_literal = 1 if flag else "foo"
-# error: "Operator `in` is not supported for types `Literal[42]` and `Literal[1]`, in comparing `Literal[42]` with `Literal[1] | Literal["foo"]`"
-e = 42 in int_literal_or_str_literal
-reveal_type(e)  # revealed: bool
-
-# TODO: should error, need to check if __lt__ signature is valid for right operand
-# error may be "Operator `<` is not supported for types `int` and `str`, in comparing `tuple[Literal[1], Literal[2]]` with `tuple[Literal[1], Literal["hello"]]`
-f = (1, 2) < (1, "hello")
-# TODO: should be Unknown, once operand type check is implemented
-reveal_type(f)  # revealed: bool
-
-# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[bool, A]` with `tuple[bool, A]`"
-g = (bool_instance(), A()) < (bool_instance(), A())
-reveal_type(g)  # revealed: Unknown
-```

crates/red_knot_python_semantic/resources/mdtest/conditional/if_expression.md

@@ -1,49 +0,0 @@
-# If expressions
-
-## Simple if-expression
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-x = 1 if flag else 2
-reveal_type(x)  # revealed: Literal[1, 2]
-```
-
-## If-expression with walrus operator
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-y = 0
-z = 0
-x = (y := 1) if flag else (z := 2)
-reveal_type(x)  # revealed: Literal[1, 2]
-reveal_type(y)  # revealed: Literal[0, 1]
-reveal_type(z)  # revealed: Literal[0, 2]
-```
-
-## Nested if-expression
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-x = 1 if flag else 2 if flag2 else 3
-reveal_type(x)  # revealed: Literal[1, 2, 3]
-```
-
-## None
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-x = 1 if flag else None
-reveal_type(x)  # revealed: Literal[1] | None
-```

crates/red_knot_python_semantic/resources/mdtest/conditional/if_statement.md

@@ -1,130 +0,0 @@
-# If statements
-
-## Simple if
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-y = 1
-y = 2
-
-if flag:
-    y = 3
-
-reveal_type(y)  # revealed: Literal[2, 3]
-```
-
-## Simple if-elif-else
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-y = 1
-y = 2
-if flag:
-    y = 3
-elif flag2:
-    y = 4
-else:
-    r = y
-    y = 5
-    s = y
-x = y
-
-reveal_type(x)  # revealed: Literal[3, 4, 5]
-
-# revealed: Literal[2]
-# error: [possibly-unresolved-reference]
-reveal_type(r)
-
-# revealed: Literal[5]
-# error: [possibly-unresolved-reference]
-reveal_type(s)
-```
-
-## Single symbol across if-elif-else
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-
-if flag:
-    y = 1
-elif flag2:
-    y = 2
-else:
-    y = 3
-reveal_type(y)  # revealed: Literal[1, 2, 3]
-```
-
-## if-elif-else without else assignment
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-y = 0
-if flag:
-    y = 1
-elif flag2:
-    y = 2
-else:
-    pass
-reveal_type(y)  # revealed: Literal[0, 1, 2]
-```
-
-## if-elif-else with intervening assignment
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-y = 0
-if flag:
-    y = 1
-    z = 3
-elif flag2:
-    y = 2
-else:
-    pass
-reveal_type(y)  # revealed: Literal[0, 1, 2]
-```
-
-## Nested if statement
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-y = 0
-if flag:
-    if flag2:
-        y = 1
-reveal_type(y)  # revealed: Literal[0, 1]
-```
-
-## if-elif without else
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag, flag2 = bool_instance(), bool_instance()
-y = 1
-y = 2
-if flag:
-    y = 3
-elif flag2:
-    y = 4
-
-reveal_type(y)  # revealed: Literal[2, 3, 4]
-```

crates/red_knot_python_semantic/resources/mdtest/conditional/match.md

@@ -1,41 +0,0 @@
-# Pattern matching
-
-## With wildcard
-
-```py
-match 0:
-    case 1:
-        y = 2
-    case _:
-        y = 3
-
-reveal_type(y)  # revealed: Literal[2, 3]
-```
-
-## Without wildcard
-
-```py
-match 0:
-    case 1:
-        y = 2
-    case 2:
-        y = 3
-
-# revealed: Literal[2, 3]
-# error: [possibly-unresolved-reference]
-reveal_type(y)
-```
-
-## Basic match
-
-```py
-y = 1
-y = 2
-match 0:
-    case 1:
-        y = 3
-    case 2:
-        y = 4
-
-reveal_type(y)  # revealed: Literal[2, 3, 4]
-```

crates/red_knot_python_semantic/resources/mdtest/declaration/error.md

@@ -1,51 +0,0 @@
-# Errors while declaring
-
-## Violates previous assignment
-
-```py
-x = 1
-x: str  # error: [invalid-declaration] "Cannot declare type `str` for inferred type `Literal[1]`"
-```
-
-## Incompatible declarations
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-if flag:
-    x: str
-else:
-    x: int
-x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
-```
-
-## Partial declarations
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-if flag:
-    x: int
-x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: Unknown, int"
-```
-
-## Incompatible declarations with bad assignment
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-if flag:
-    x: str
-else:
-    x: int
-
-# error: [conflicting-declarations]
-# error: [invalid-assignment]
-x = b"foo"
-```

crates/red_knot_python_semantic/resources/mdtest/exception/basic.md

@@ -1,60 +0,0 @@
-# Exception Handling
-
-## Single Exception
-
-```py
-import re
-
-try:
-    help()
-except NameError as e:
-    reveal_type(e)  # revealed: NameError
-except re.error as f:
-    reveal_type(f)  # revealed: error
-```
-
-## Unknown type in except handler does not cause spurious diagnostic
-
-```py
-from nonexistent_module import foo  # error: [unresolved-import]
-
-try:
-    help()
-except foo as e:
-    reveal_type(foo)  # revealed: Unknown
-    reveal_type(e)  # revealed: Unknown
-```
-
-## Multiple Exceptions in a Tuple
-
-```py
-EXCEPTIONS = (AttributeError, TypeError)
-
-try:
-    help()
-except (RuntimeError, OSError) as e:
-    reveal_type(e)  # revealed: RuntimeError | OSError
-except EXCEPTIONS as f:
-    reveal_type(f)  # revealed: AttributeError | TypeError
-```
-
-## Dynamic exception types
-
-```py
-def foo(
-    x: type[AttributeError],
-    y: tuple[type[OSError], type[RuntimeError]],
-    z: tuple[type[BaseException], ...],
-):
-    try:
-        help()
-    except x as e:
-        # TODO: should be `AttributeError`
-        reveal_type(e)  # revealed: @Todo(exception type)
-    except y as f:
-        # TODO: should be `OSError | RuntimeError`
-        reveal_type(f)  # revealed: @Todo(exception type)
-    except z as g:
-        # TODO: should be `BaseException`
-        reveal_type(g)  # revealed: @Todo(exception type)
-```