Use Invalid context when keyword used as identifier

2024-12-03 16:53:40 +05:30
358 changed files with 5627 additions and 19236 deletions
--- a/.github/workflows/build-binaries.yml
+++ b/.github/workflows/build-binaries.yml
@@ -40,7 +40,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -53,9 +52,9 @@ jobs:
          args: --out dist
      - name: "Test sdist"
        run: |
-          pip install dist/${PACKAGE_NAME}-*.tar.gz --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          pip install dist/${{ env.PACKAGE_NAME }}-*.tar.gz --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
      - name: "Upload sdist"
        uses: actions/upload-artifact@v4
        with:
@@ -69,7 +68,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -111,7 +109,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -125,7 +122,7 @@ jobs:
          args: --release --locked --out dist
      - name: "Test wheel - aarch64"
        run: |
-          pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
          ruff --help
          python -m ruff --help
      - name: "Upload wheels"
@@ -167,7 +164,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -186,9 +182,9 @@ jobs:
        if: ${{ !startsWith(matrix.platform.target, 'aarch64') }}
        shell: bash
        run: |
-          python -m pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          python -m pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
      - name: "Upload wheels"
        uses: actions/upload-artifact@v4
        with:
@@ -220,7 +216,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -236,9 +231,9 @@ jobs:
      - name: "Test wheel"
        if: ${{ startsWith(matrix.target, 'x86_64') }}
        run: |
-          pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
      - name: "Upload wheels"
        uses: actions/upload-artifact@v4
        with:
@@ -295,7 +290,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -360,7 +354,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -426,7 +419,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
--- a/.github/workflows/build-docker.yml
+++ b/.github/workflows/build-docker.yml
@@ -36,7 +36,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          submodules: recursive
-          persist-credentials: false

      - uses: docker/setup-buildx-action@v3

@@ -72,7 +71,7 @@ jobs:
      - name: Normalize Platform Pair (replace / with -)
        run: |
          platform=${{ matrix.platform }}
-          echo "PLATFORM_TUPLE=${platform//\//-}" >> "$GITHUB_ENV"
+          echo "PLATFORM_TUPLE=${platform//\//-}" >> $GITHUB_ENV

      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
      - name: Build and push by digest
@@ -87,10 +86,9 @@ jobs:
          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
-        env:
-          digest: ${{ steps.build.outputs.digest }}
        run: |
          mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digests
@@ -144,7 +142,7 @@ jobs:
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)
+            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)

  docker-publish-extra:
    name: Publish additional Docker image based on ${{ matrix.image-mapping }}
@@ -183,7 +181,7 @@ jobs:
          # Generate Dockerfile content
          cat <<EOF > Dockerfile
          FROM ${BASE_IMAGE}
-          COPY --from=${RUFF_BASE_IMG}:latest /ruff /usr/local/bin/ruff
+          COPY --from=${{ env.RUFF_BASE_IMG }}:latest /ruff /usr/local/bin/ruff
          ENTRYPOINT []
          CMD ["/usr/local/bin/ruff"]
          EOF
@@ -203,14 +201,14 @@ jobs:
          TAG_PATTERNS="${TAG_PATTERNS%\\n}"

          # Export image cache name
-          echo "IMAGE_REF=${BASE_IMAGE//:/-}" >> "$GITHUB_ENV"
+          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"
+          } >> $GITHUB_ENV

      - name: Extract metadata (tags, labels) for Docker
        id: meta
@@ -289,4 +287,4 @@ jobs:
          docker buildx imagetools create \
            "${annotations[@]}" \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)
+            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -32,13 +32,10 @@ jobs:
      # Flag that is raised when any code is changed
      # This is superset of the linter and formatter
      code: ${{ steps.changed.outputs.code_any_changed }}
-      # Flag that is raised when any code that affects the fuzzer is changed
-      fuzz: ${{ steps.changed.outputs.fuzz_any_changed }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
-          persist-credentials: false

      - uses: tj-actions/changed-files@v45
        id: changed
@@ -82,11 +79,6 @@ jobs:
              - python/**
              - .github/workflows/ci.yaml

-            fuzz:
-              - fuzz/Cargo.toml
-              - fuzz/Cargo.lock
-              - fuzz/fuzz_targets/**
-
            code:
              - "**/*"
              - "!**/*.md"
@@ -100,8 +92,6 @@ jobs:
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup component add rustfmt
      - run: cargo fmt --all --check
@@ -114,8 +104,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: |
          rustup component add clippy
@@ -134,8 +122,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
@@ -180,8 +166,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
@@ -209,8 +193,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install cargo nextest"
@@ -235,8 +217,6 @@ jobs:
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup target add wasm32-unknown-unknown
      - uses: actions/setup-node@v4
@@ -264,8 +244,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Install mold"
@@ -282,8 +260,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: SebRollen/toml-action@v1.2.0
        id: msrv
        with:
@@ -312,12 +288,10 @@ jobs:
    name: "cargo fuzz build"
    runs-on: ubuntu-latest
    needs: determine_changes
-    if: ${{ github.ref == 'refs/heads/main' || needs.determine_changes.outputs.fuzz == 'true' }}
+    if: ${{ github.ref == 'refs/heads/main' }}
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - uses: Swatinem/rust-cache@v2
@@ -344,8 +318,6 @@ jobs:
      FORCE_COLOR: 1
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: astral-sh/setup-uv@v4
      - uses: actions/download-artifact@v4
        name: Download Ruff binary to test
@@ -376,8 +348,6 @@ jobs:
    timeout-minutes: 5
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup component add rustfmt
      - uses: Swatinem/rust-cache@v2
@@ -402,8 +372,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -514,8 +482,6 @@ jobs:
    if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: cargo-bins/cargo-binstall@main
      - run: cargo binstall --no-confirm cargo-shear
      - run: cargo shear
@@ -526,8 +492,6 @@ jobs:
    timeout-minutes: 20
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -553,8 +517,6 @@ jobs:
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ env.PYTHON_VERSION }}
@@ -586,8 +548,6 @@ jobs:
      MKDOCS_INSIDERS_SSH_KEY_EXISTS: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY != '' }}
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: actions/setup-python@v5
        with:
          python-version: "3.13"
@@ -628,8 +588,6 @@ jobs:
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup show
      - name: "Cache rust"
@@ -657,7 +615,6 @@ jobs:
      - uses: actions/checkout@v4
        name: "Download ruff-lsp source"
        with:
-          persist-credentials: false
          repository: "astral-sh/ruff-lsp"

      - uses: actions/setup-python@v5
@@ -693,8 +650,6 @@ jobs:
    steps:
      - name: "Checkout Branch"
        uses: actions/checkout@v4
-        with:
-          persist-credentials: false

      - name: "Install Rust toolchain"
        run: rustup show
--- a/.github/workflows/daily_fuzz.yaml
+++ b/.github/workflows/daily_fuzz.yaml
@@ -32,8 +32,6 @@ jobs:
    if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - uses: astral-sh/setup-uv@v4
      - name: "Install Rust toolchain"
        run: rustup show
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -26,7 +26,6 @@ jobs:
      - uses: actions/checkout@v4
        with:
          ref: ${{ inputs.ref }}
-          persist-credentials: true

      - uses: actions/setup-python@v5
        with:
@@ -49,11 +48,13 @@ jobs:

      - 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 '-')"
+          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
@@ -91,7 +92,9 @@ jobs:
        run: mkdocs build --strict -f mkdocs.public.yml

      - name: "Clone docs repo"
-        run: git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
+        run: |
+          version="${{ 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/
@@ -99,10 +102,12 @@ jobs:
      - 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 checkout -b $branch_name
          git add site/ruff
          git commit -m "Update ruff documentation for $version"

@@ -111,8 +116,12 @@ jobs:
        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}""
+          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
@@ -121,12 +130,12 @@ jobs:
            xargs -I {} gh pr close {}

          # push the branch to GitHub
-          git push origin "${branch_name}"
+          git push origin $branch_name

          # create the PR
-          gh pr create --base main --head "${branch_name}" \
+          gh pr create --base main --head $branch_name \
            --title "$pull_request_title" \
-            --body "Automated documentation update for "${display_name}"" \
+            --body "Automated documentation update for $display_name" \
            --label "documentation"

      - name: "Merge Pull Request"
@@ -135,7 +144,9 @@ jobs:
        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}"
+          gh pr merge --squash $branch_name
--- a/.github/workflows/publish-playground.yml
+++ b/.github/workflows/publish-playground.yml
@@ -25,8 +25,6 @@ jobs:
      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup target add wasm32-unknown-unknown
      - uses: actions/setup-node@v4
--- a/.github/workflows/publish-wasm.yml
+++ b/.github/workflows/publish-wasm.yml
@@ -30,8 +30,6 @@ jobs:
      fail-fast: false
    steps:
      - uses: actions/checkout@v4
-        with:
-          persist-credentials: false
      - name: "Install Rust toolchain"
        run: rustup target add wasm32-unknown-unknown
      - uses: jetli/wasm-pack-action@v0.4.0
--- a/.github/workflows/sync_typeshed.yaml
+++ b/.github/workflows/sync_typeshed.yaml
@@ -25,13 +25,11 @@ jobs:
        name: Checkout Ruff
        with:
          path: ruff
-          persist-credentials: true
      - uses: actions/checkout@v4
        name: Checkout typeshed
        with:
          repository: python/typeshed
          path: typeshed
-          persist-credentials: false
      - name: Setup git
        run: |
          git config --global user.name typeshedbot
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -59,7 +59,7 @@ repos:
          - black==24.10.0

  - repo: https://github.com/crate-ci/typos
-    rev: v1.28.2
+    rev: v1.28.1
    hooks:
      - id: typos

@@ -73,7 +73,7 @@ repos:
        pass_filenames: false # This makes it a lot faster

  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.8.2
+    rev: v0.8.1
    hooks:
      - id: ruff-format
      - id: ruff
@@ -83,23 +83,10 @@ repos:

  # Prettier
  - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.4.2
+    rev: v3.4.1
    hooks:
      - id: prettier
        types: [yaml]

-  - repo: https://github.com/woodruffw/zizmor-pre-commit
-    rev: v0.8.0
-    hooks:
-      - id: zizmor
-        # `release.yml` is autogenerated by `dist`; security issues need to be fixed there
-        # (https://opensource.axo.dev/cargo-dist/)
-        exclude: .github/workflows/release.yml
-
-  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.30.0
-    hooks:
-      - id: check-github-workflows
-
 ci:
  skip: [cargo-fmt, dev-generate-all]
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,77 +1,5 @@
 # Changelog

-## 0.8.3
-
-### Preview features
-
- Fix fstring formatting removing overlong implicit concatenated string in expression part ([#14811](https://github.com/astral-sh/ruff/pull/14811))
- \[`airflow`\] Add fix to remove deprecated keyword arguments (`AIR302`) ([#14887](https://github.com/astral-sh/ruff/pull/14887))
- \[`airflow`\]: Extend rule to include deprecated names for Airflow 3.0 (`AIR302`) ([#14765](https://github.com/astral-sh/ruff/pull/14765) and [#14804](https://github.com/astral-sh/ruff/pull/14804))
- \[`flake8-bugbear`\] Improve error messages for `except*` (`B025`, `B029`, `B030`, `B904`) ([#14815](https://github.com/astral-sh/ruff/pull/14815))
- \[`flake8-bugbear`\] `itertools.batched()` without explicit `strict` (`B911`) ([#14408](https://github.com/astral-sh/ruff/pull/14408))
- \[`flake8-use-pathlib`\] Dotless suffix passed to `Path.with_suffix()` (`PTH210`) ([#14779](https://github.com/astral-sh/ruff/pull/14779))
- \[`pylint`\] Include parentheses and multiple comparators in check for `boolean-chained-comparison` (`PLR1716`) ([#14781](https://github.com/astral-sh/ruff/pull/14781))
- \[`ruff`\] Do not simplify `round()` calls (`RUF046`) ([#14832](https://github.com/astral-sh/ruff/pull/14832))
- \[`ruff`\] Don't emit `used-dummy-variable` on function parameters (`RUF052`) ([#14818](https://github.com/astral-sh/ruff/pull/14818))
- \[`ruff`\] Implement `if-key-in-dict-del` (`RUF051`) ([#14553](https://github.com/astral-sh/ruff/pull/14553))
- \[`ruff`\] Mark autofix for `RUF052` as always unsafe ([#14824](https://github.com/astral-sh/ruff/pull/14824))
- \[`ruff`\] Teach autofix for `used-dummy-variable` about TypeVars etc. (`RUF052`) ([#14819](https://github.com/astral-sh/ruff/pull/14819))
-
-### Rule changes
-
- \[`flake8-bugbear`\] Offer unsafe autofix for `no-explicit-stacklevel` (`B028`) ([#14829](https://github.com/astral-sh/ruff/pull/14829))
- \[`flake8-pyi`\] Skip all type definitions in `string-or-bytes-too-long` (`PYI053`) ([#14797](https://github.com/astral-sh/ruff/pull/14797))
- \[`pyupgrade`\] Do not report when a UTF-8 comment is followed by a non-UTF-8 one (`UP009`) ([#14728](https://github.com/astral-sh/ruff/pull/14728))
- \[`pyupgrade`\] Mark fixes for `convert-typed-dict-functional-to-class` and `convert-named-tuple-functional-to-class` as unsafe if they will remove comments (`UP013`, `UP014`) ([#14842](https://github.com/astral-sh/ruff/pull/14842))
-
-### Bug fixes
-
- Raise syntax error for mixing `except` and `except*` ([#14895](https://github.com/astral-sh/ruff/pull/14895))
- \[`flake8-bugbear`\] Fix `B028` to allow `stacklevel` to be explicitly assigned as a positional argument ([#14868](https://github.com/astral-sh/ruff/pull/14868))
- \[`flake8-bugbear`\] Skip `B028` if `warnings.warn` is called with `*args` or `**kwargs` ([#14870](https://github.com/astral-sh/ruff/pull/14870))
- \[`flake8-comprehensions`\] Skip iterables with named expressions in `unnecessary-map` (`C417`) ([#14827](https://github.com/astral-sh/ruff/pull/14827))
- \[`flake8-pyi`\] Also remove `self` and `cls`'s annotation (`PYI034`) ([#14801](https://github.com/astral-sh/ruff/pull/14801))
- \[`flake8-pytest-style`\] Fix `pytest-parametrize-names-wrong-type` (`PT006`) to edit both `argnames` and `argvalues` if both of them are single-element tuples/lists ([#14699](https://github.com/astral-sh/ruff/pull/14699))
- \[`perflint`\] Improve autofix for `PERF401` ([#14369](https://github.com/astral-sh/ruff/pull/14369))
- \[`pylint`\] Fix `PLW1508` false positive for default string created via a mult operation ([#14841](https://github.com/astral-sh/ruff/pull/14841))
-
-## 0.8.2
-
-### Preview features
-
- \[`airflow`\] Avoid deprecated values (`AIR302`) ([#14582](https://github.com/astral-sh/ruff/pull/14582))
- \[`airflow`\] Extend removed names for `AIR302` ([#14734](https://github.com/astral-sh/ruff/pull/14734))
- \[`ruff`\] Extend `unnecessary-regular-expression` to non-literal strings (`RUF055`) ([#14679](https://github.com/astral-sh/ruff/pull/14679))
- \[`ruff`\] Implement `used-dummy-variable` (`RUF052`) ([#14611](https://github.com/astral-sh/ruff/pull/14611))
- \[`ruff`\] Implement `unnecessary-cast-to-int` (`RUF046`) ([#14697](https://github.com/astral-sh/ruff/pull/14697))
-
-### Rule changes
-
- \[`airflow`\] Check `AIR001` from builtin or providers `operators` module ([#14631](https://github.com/astral-sh/ruff/pull/14631))
- \[`flake8-pytest-style`\] Remove `@` in `pytest.mark.parametrize` rule messages ([#14770](https://github.com/astral-sh/ruff/pull/14770))
- \[`pandas-vet`\] Skip rules if the `panda` module hasn't been seen ([#14671](https://github.com/astral-sh/ruff/pull/14671))
- \[`pylint`\] Fix false negatives for `ascii` and `sorted` in `len-as-condition` (`PLC1802`) ([#14692](https://github.com/astral-sh/ruff/pull/14692))
- \[`refurb`\] Guard `hashlib` imports and mark `hashlib-digest-hex` fix as safe (`FURB181`) ([#14694](https://github.com/astral-sh/ruff/pull/14694))
-
-### Configuration
-
- \[`flake8-import-conventions`\] Improve syntax check for aliases supplied in configuration for `unconventional-import-alias` (`ICN001`) ([#14745](https://github.com/astral-sh/ruff/pull/14745))
-
-### Bug fixes
-
- Revert: [pyflakes] Avoid false positives in `@no_type_check` contexts (`F821`, `F722`) (#14615) ([#14726](https://github.com/astral-sh/ruff/pull/14726))
- \[`pep8-naming`\] Avoid false positive for `class Bar(type(foo))` (`N804`) ([#14683](https://github.com/astral-sh/ruff/pull/14683))
- \[`pycodestyle`\] Handle f-strings properly for `invalid-escape-sequence` (`W605`) ([#14748](https://github.com/astral-sh/ruff/pull/14748))
- \[`pylint`\] Ignore `@overload` in `PLR0904` ([#14730](https://github.com/astral-sh/ruff/pull/14730))
- \[`refurb`\] Handle non-finite decimals in `verbose-decimal-constructor` (`FURB157`) ([#14596](https://github.com/astral-sh/ruff/pull/14596))
- \[`ruff`\] Avoid emitting `assignment-in-assert` when all references to the assigned variable are themselves inside `assert`s (`RUF018`) ([#14661](https://github.com/astral-sh/ruff/pull/14661))
-
-### Documentation
-
- Improve docs for `flake8-use-pathlib` rules ([#14741](https://github.com/astral-sh/ruff/pull/14741))
- Improve error messages and docs for `flake8-comprehensions` rules ([#14729](https://github.com/astral-sh/ruff/pull/14729))
- \[`flake8-type-checking`\] Expands `TC006` docs to better explain itself ([#14749](https://github.com/astral-sh/ruff/pull/14749))
-
 ## 0.8.1

 ### Preview features
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -117,9 +117,9 @@ dependencies = [

 [[package]]
 name = "anyhow"
-version = "1.0.94"
+version = "1.0.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1fd03a028ef38ba2276dce7e33fcd6369c158a1bca17946c4b1b701891c1ff7"
+checksum = "4c95c10ba0b00a02636238b814946408b1322d5ac4760326e6fb8ec956d85775"

 [[package]]
 name = "append-only-vec"
@@ -276,13 +276,13 @@ dependencies = [

 [[package]]
 name = "cc"
-version = "1.2.2"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f34d93e62b03caf570cccc334cbc6c2fceca82f39211051345108adcba3eebdc"
+checksum = "d32a725bc159af97c3e629873bb9f88fb8cf8a4867175f76dc987815ea07c83b"
 dependencies = [
 "jobserver",
 "libc",
- "shlex",
+ "once_cell",
 ]

 [[package]]
@@ -353,9 +353,9 @@ dependencies = [

 [[package]]
 name = "clap"
-version = "4.5.23"
+version = "4.5.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3135e7ec2ef7b10c6ed8950f0f792ed96ee093fa088608f1c76e569722700c84"
+checksum = "fb3b4b9e5a7c7514dfa52869339ee98b3156b0bfb4e8a77c4ff4babb64b1604f"
 dependencies = [
 "clap_builder",
 "clap_derive",
@@ -363,9 +363,9 @@ dependencies = [

 [[package]]
 name = "clap_builder"
-version = "4.5.23"
+version = "4.5.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30582fc632330df2bd26877bde0c1f4470d57c582bbc070376afcd04d8cb4838"
+checksum = "b17a95aa67cc7b5ebd32aa5370189aa0d79069ef1c64ce893bd30fb24bff20ec"
 dependencies = [
 "anstream",
 "anstyle",
@@ -413,14 +413,14 @@ dependencies = [
 "heck",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
 name = "clap_lex"
-version = "0.7.4"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f46ad14479a25103f283c0f10005961cf086d8dc42205bb44c46ac563475dca6"
+checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"

 [[package]]
 name = "clearscreen"
@@ -693,7 +693,7 @@ dependencies = [
 "proc-macro2",
 "quote",
 "strsim 0.10.0",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -704,7 +704,7 @@ checksum = "a668eda54683121533a393014d8692171709ff57a7d61f187b6e782719f8933f"
 dependencies = [
 "darling_core",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -758,23 +758,23 @@ dependencies = [

 [[package]]
 name = "dir-test"
-version = "0.4.1"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62c013fe825864f3e4593f36426c1fa7a74f5603f13ca8d1af7a990c1cd94a79"
+checksum = "b12781621d53fd9087021f5a338df5c57c04f84a6231c1f4726f45e2e333470b"
 dependencies = [
 "dir-test-macros",
 ]

 [[package]]
 name = "dir-test-macros"
-version = "0.4.1"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d42f54d7b4a6bc2400fe5b338e35d1a335787585375322f49c5d5fe7b243da7e"
+checksum = "1340852f50b2285d01a7f598cc5d08b572669c3e09e614925175cc3c26787b91"
 dependencies = [
 "glob",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -826,7 +826,7 @@ checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -1246,7 +1246,7 @@ checksum = "1ec89e9337638ecdc08744df490b221a7399bf8d164eb52a665454e60e075ad6"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -1420,7 +1420,7 @@ dependencies = [
 "heck",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -1547,7 +1547,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2ae40017ac09cd2c6a53504cb3c871c7f2b41466eac5bc66ba63f39073b467b"
 dependencies = [
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -1944,11 +1944,10 @@ checksum = "e3aeb8f54c078314c2065ee649a7241f46b9d8e418e1a9581ba0546657d7aa3a"

 [[package]]
 name = "pep440_rs"
-version = "0.7.3"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31095ca1f396e3de32745f42b20deef7bc09077f918b085307e8eab6ddd8fb9c"
+checksum = "0922a442c78611fa8c5ed6065d2d898a820cf12fa90604217fdb2d01675efec7"
 dependencies = [
- "once_cell",
 "serde",
 "unicode-width 0.2.0",
 "unscanny",
@@ -2014,7 +2013,7 @@ dependencies = [
 "pest_meta",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -2161,7 +2160,7 @@ dependencies = [
 "newtype-uuid",
 "quick-xml",
 "strip-ansi-escapes",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "uuid",
 ]

@@ -2174,26 +2173,6 @@ dependencies = [
 "memchr",
 ]

-[[package]]
-name = "quickcheck"
-version = "1.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "588f6378e4dd99458b60ec275b4477add41ce4fa9f64dcba6f15adccb19b50d6"
-dependencies = [
- "rand",
-]
-
-[[package]]
-name = "quickcheck_macros"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b22a693222d716a9587786f37ac3f6b4faedb5b80c23914e7303ff5a1d8016e9"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn 1.0.109",
-]
-
 [[package]]
 name = "quote"
 version = "1.0.37"
@@ -2294,13 +2273,10 @@ dependencies = [
 "itertools 0.13.0",
 "memchr",
 "ordermap",
- "quickcheck",
- "quickcheck_macros",
 "red_knot_test",
 "red_knot_vendored",
 "ruff_db",
 "ruff_index",
- "ruff_macros",
 "ruff_python_ast",
 "ruff_python_literal",
 "ruff_python_parser",
@@ -2314,7 +2290,7 @@ dependencies = [
 "static_assertions",
 "tempfile",
 "test-case",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "tracing",
 ]

@@ -2360,9 +2336,7 @@ dependencies = [
 "ruff_text_size",
 "rustc-hash 2.1.0",
 "salsa",
- "serde",
 "smallvec",
- "toml",
 ]

 [[package]]
@@ -2411,7 +2385,7 @@ dependencies = [
 "rustc-hash 2.1.0",
 "salsa",
 "serde",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "toml",
 "tracing",
 ]
@@ -2517,7 +2491,7 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.8.3"
+version = "0.8.1"
 dependencies = [
 "anyhow",
 "argfile",
@@ -2564,7 +2538,7 @@ dependencies = [
 "strum",
 "tempfile",
 "test-case",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "tikv-jemallocator",
 "toml",
 "tracing",
@@ -2634,7 +2608,7 @@ dependencies = [
 "salsa",
 "serde",
 "tempfile",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "tracing",
 "tracing-subscriber",
 "tracing-tree",
@@ -2736,7 +2710,7 @@ dependencies = [

 [[package]]
 name = "ruff_linter"
-version = "0.8.3"
+version = "0.8.1"
 dependencies = [
 "aho-corasick",
 "annotate-snippets 0.9.2",
@@ -2786,7 +2760,7 @@ dependencies = [
 "strum",
 "strum_macros",
 "test-case",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "toml",
 "typed-arena",
 "unicode-normalization",
@@ -2803,7 +2777,7 @@ dependencies = [
 "proc-macro2",
 "quote",
 "ruff_python_trivia",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -2820,7 +2794,7 @@ dependencies = [
 "serde_json",
 "serde_with",
 "test-case",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "uuid",
 ]

@@ -2892,7 +2866,7 @@ dependencies = [
 "similar",
 "smallvec",
 "static_assertions",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "tracing",
 ]

@@ -3025,7 +2999,7 @@ dependencies = [
 "serde",
 "serde_json",
 "shellexpand",
- "thiserror 2.0.6",
+ "thiserror 2.0.3",
 "tracing",
 "tracing-subscriber",
 ]
@@ -3051,7 +3025,7 @@ dependencies = [

 [[package]]
 name = "ruff_wasm"
-version = "0.8.3"
+version = "0.8.1"
 dependencies = [
 "console_error_panic_hook",
 "console_log",
@@ -3223,7 +3197,7 @@ dependencies = [
 "heck",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "synstructure",
 ]

@@ -3257,7 +3231,7 @@ dependencies = [
 "proc-macro2",
 "quote",
 "serde_derive_internals",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3306,7 +3280,7 @@ checksum = "ad1e866f866923f252f05c889987993144fb74e722403468a4ebd70c3cd756c0"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3317,7 +3291,7 @@ checksum = "330f01ce65a3a5fe59a60c82f3c9a024b573b8a6e875bd233fe5f934e71d54e3"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3340,7 +3314,7 @@ checksum = "6c64451ba24fc7a6a2d60fc75dd9c83c90903b19028d4eff35e88fc1e86564e9"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3381,7 +3355,7 @@ dependencies = [
 "darling",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3413,12 +3387,6 @@ dependencies = [
 "dirs 5.0.1",
 ]

-[[package]]
-name = "shlex"
-version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
-
 [[package]]
 name = "similar"
 version = "2.6.0"
@@ -3495,7 +3463,7 @@ dependencies = [
 "proc-macro2",
 "quote",
 "rustversion",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3504,17 +3472,6 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "81cdd64d312baedb58e21336b31bc043b77e01cc99033ce76ef539f78e965ebc"

-[[package]]
-name = "syn"
-version = "1.0.109"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-ident",
-]
-
 [[package]]
 name = "syn"
 version = "2.0.90"
@@ -3534,7 +3491,7 @@ checksum = "c8af7666ab7b6390ab78131fb5b0fce11d6b7a6951602017c35fa82800708971"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3597,7 +3554,7 @@ dependencies = [
 "cfg-if",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3608,7 +3565,7 @@ checksum = "5c89e72a01ed4c579669add59014b9a524d609c0c88c6a585ce37485879f6ffb"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "test-case-core",
 ]

@@ -3623,11 +3580,11 @@ dependencies = [

 [[package]]
 name = "thiserror"
-version = "2.0.6"
+version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fec2a1820ebd077e2b90c4df007bebf344cd394098a13c563957d0afc83ea47"
+checksum = "c006c85c7651b3cf2ada4584faa36773bd07bac24acfb39f3c431b36d7e667aa"
 dependencies = [
- "thiserror-impl 2.0.6",
+ "thiserror-impl 2.0.3",
 ]

 [[package]]
@@ -3638,18 +3595,18 @@ checksum = "b607164372e89797d78b8e23a6d67d5d1038c1c65efd52e1389ef8b77caba2a6"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
 name = "thiserror-impl"
-version = "2.0.6"
+version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d65750cab40f4ff1929fb1ba509e9914eb756131cef4210da8d5d700d26f6312"
+checksum = "f077553d607adc1caf65430528a576c757a71ed73944b66ebb58ef2bbd243568"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3771,7 +3728,7 @@ checksum = "395ae124c09f9e6918a2310af6038fba074bcf474ac352496d5910dd59a2226d"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -3797,9 +3754,9 @@ dependencies = [

 [[package]]
 name = "tracing-indicatif"
-version = "0.3.8"
+version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74ba258e9de86447f75edf6455fded8e5242704c6fccffe7bf8d7fb6daef1180"
+checksum = "069580424efe11d97c3fef4197fa98c004fa26672cc71ad8770d224e23b1951d"
 dependencies = [
 "indicatif",
 "tracing",
@@ -3971,18 +3928,21 @@ checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"

 [[package]]
 name = "ureq"
-version = "2.12.1"
+version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02d1a66277ed75f640d608235660df48c8e3c19f3b4edb6a263315626cc3c01d"
+checksum = "b30e6f97efe1fa43535ee241ee76967d3ff6ff3953ebb430d8d55c5393029e7b"
 dependencies = [
 "base64 0.22.0",
 "flate2",
+ "litemap",
 "log",
 "once_cell",
 "rustls",
 "rustls-pki-types",
 "url",
 "webpki-roots",
+ "yoke",
+ "zerofrom",
 ]

 [[package]]
@@ -4041,7 +4001,7 @@ checksum = "6b91f57fe13a38d0ce9e28a03463d8d3c2468ed03d75375110ec71d93b449a08"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -4136,7 +4096,7 @@ dependencies = [
 "once_cell",
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "wasm-bindgen-shared",
 ]

@@ -4171,7 +4131,7 @@ checksum = "98c9ae5a76e46f4deecd0f0255cc223cfa18dc9b261213b8aa0c7b36f61b3f1d"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "wasm-bindgen-backend",
 "wasm-bindgen-shared",
 ]
@@ -4205,7 +4165,7 @@ checksum = "222ebde6ea87fbfa6bdd2e9f1fd8a91d60aee5db68792632176c4e16a74fc7d8"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -4508,7 +4468,7 @@ checksum = "28cc31741b18cb6f1d5ff12f5b7523e3d6eb0852bbbad19d73905511d9849b95"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "synstructure",
 ]

@@ -4529,7 +4489,7 @@ checksum = "9ce1b18ccd8e73a9321186f97e46f9f04b778851177567b1975109d26a08d2a6"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
@@ -4549,7 +4509,7 @@ checksum = "0ea7b4a3637ea8669cedf0f1fd5c286a17f3de97b8dd5a70a6c167a1730e63a5"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 "synstructure",
 ]

@@ -4578,7 +4538,7 @@ checksum = "6eafa6dfb17584ea3e2bd6e76e0cc15ad7af12b09abdd1ca55961bed9b1063c6"
 dependencies = [
 "proc-macro2",
 "quote",
- "syn 2.0.90",
+ "syn",
 ]

 [[package]]
--- a/README.md
+++ b/README.md
@@ -119,10 +119,6 @@ For more, see the [documentation](https://docs.astral.sh/ruff/).
 Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:

 ```shell
-# With uv.
-uv add --dev ruff     # to add ruff to your project
-uv tool install ruff  # to install ruff globally
-
 # With pip.
 pip install ruff

@@ -140,8 +136,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"

 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.8.3/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.8.3/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.8.1/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.8.1/install.ps1 | iex"
 ```

 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -174,7 +170,7 @@ 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: v0.8.3
+  rev: v0.8.1
  hooks:
    # Run the linter.
    - id: ruff
--- a/crates/red_knot/tests/file_watching.rs
+++ b/crates/red_knot/tests/file_watching.rs
@@ -1,23 +1,25 @@
 #![allow(clippy::disallowed_names)]

 use std::io::Write;
-use std::time::{Duration, Instant};
+use std::time::Duration;

 use anyhow::{anyhow, Context};
 use red_knot_python_semantic::{resolve_module, ModuleName, Program, PythonVersion, SitePackages};
 use red_knot_workspace::db::{Db, RootDatabase};
-use red_knot_workspace::watch::{directory_watcher, ChangeEvent, WorkspaceWatcher};
+use red_knot_workspace::watch;
+use red_knot_workspace::watch::{directory_watcher, WorkspaceWatcher};
 use red_knot_workspace::workspace::settings::{Configuration, SearchPathConfiguration};
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File, FileError};
 use ruff_db::source::source_text;
 use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
+use ruff_db::testing::{setup_logging, setup_logging_with_filter};
 use ruff_db::Upcast;

 struct TestCase {
    db: RootDatabase,
    watcher: Option<WorkspaceWatcher>,
-    changes_receiver: crossbeam::channel::Receiver<Vec<ChangeEvent>>,
+    changes_receiver: crossbeam::channel::Receiver<Vec<watch::ChangeEvent>>,
    /// The temporary directory that contains the test files.
    /// We need to hold on to it in the test case or the temp files get deleted.
    _temp_dir: tempfile::TempDir,
@@ -38,36 +40,12 @@ impl TestCase {
        &self.db
    }

-    #[track_caller]
-    fn stop_watch<M>(&mut self, matcher: M) -> Vec<ChangeEvent>
-    where
-        M: MatchEvent,
-    {
-        // track_caller is unstable for lambdas -> That's why this is a fn
-        #[track_caller]
-        fn panic_with_formatted_events(events: Vec<ChangeEvent>) -> Vec<ChangeEvent> {
-            panic!(
-                "Didn't observe expected change:\n{}",
-                events
-                    .into_iter()
-                    .map(|event| format!("  - {event:?}"))
-                    .collect::<Vec<_>>()
-                    .join("\n")
-            )
-        }
-
-        self.try_stop_watch(matcher, Duration::from_secs(10))
-            .unwrap_or_else(panic_with_formatted_events)
+    fn stop_watch(&mut self) -> Vec<watch::ChangeEvent> {
+        self.try_stop_watch(Duration::from_secs(10))
+            .expect("Expected watch changes but observed none")
    }

-    fn try_stop_watch<M>(
-        &mut self,
-        mut matcher: M,
-        timeout: Duration,
-    ) -> Result<Vec<ChangeEvent>, Vec<ChangeEvent>>
-    where
-        M: MatchEvent,
-    {
+    fn try_stop_watch(&mut self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
        tracing::debug!("Try stopping watch with timeout {:?}", timeout);

        let watcher = self
@@ -75,50 +53,36 @@ impl TestCase {
            .take()
            .expect("Cannot call `stop_watch` more than once");

-        let start = Instant::now();
-        let mut all_events = Vec::new();
-
-        loop {
-            let events = self
-                .changes_receiver
-                .recv_timeout(Duration::from_millis(100))
-                .unwrap_or_default();
-
-            if events
-                .iter()
-                .any(|event| matcher.match_event(event) || event.is_rescan())
-            {
-                all_events.extend(events);
-                break;
-            }
-
-            all_events.extend(events);
-
-            if start.elapsed() > timeout {
-                return Err(all_events);
-            }
-        }
+        let mut all_events = self
+            .changes_receiver
+            .recv_timeout(timeout)
+            .unwrap_or_default();

        watcher.flush();
        tracing::debug!("Flushed file watcher");
        watcher.stop();
        tracing::debug!("Stopping file watcher");

-        // Consume remaining events
        for event in &self.changes_receiver {
            all_events.extend(event);
        }

-        Ok(all_events)
+        if all_events.is_empty() {
+            return None;
+        }
+
+        Some(all_events)
    }

-    fn take_watch_changes(&self) -> Vec<ChangeEvent> {
+    fn take_watch_changes(&self) -> Vec<watch::ChangeEvent> {
        self.try_take_watch_changes(Duration::from_secs(10))
            .expect("Expected watch changes but observed none")
    }

-    fn try_take_watch_changes(&self, timeout: Duration) -> Option<Vec<ChangeEvent>> {
-        let watcher = self.watcher.as_ref()?;
+    fn try_take_watch_changes(&self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
+        let Some(watcher) = &self.watcher else {
+            return None;
+        };

        let mut all_events = self
            .changes_receiver
@@ -140,7 +104,7 @@ impl TestCase {
        Some(all_events)
    }

-    fn apply_changes(&mut self, changes: Vec<ChangeEvent>) {
+    fn apply_changes(&mut self, changes: Vec<watch::ChangeEvent>) {
        self.db.apply_changes(changes, Some(&self.configuration));
    }

@@ -176,23 +140,6 @@ impl TestCase {
    }
 }

-trait MatchEvent {
-    fn match_event(&mut self, event: &ChangeEvent) -> bool;
-}
-
-fn event_for_file(name: &str) -> impl MatchEvent + '_ {
-    |event: &ChangeEvent| event.file_name() == Some(name)
-}
-
-impl<F> MatchEvent for F
-where
-    F: FnMut(&ChangeEvent) -> bool,
-{
-    fn match_event(&mut self, event: &ChangeEvent) -> bool {
-        (*self)(event)
-    }
-}
-
 trait SetupFiles {
    fn setup(self, root_path: &SystemPath, workspace_path: &SystemPath) -> anyhow::Result<()>;
 }
@@ -368,7 +315,7 @@ fn new_file() -> anyhow::Result<()> {

    std::fs::write(foo_path.as_std_path(), "print('Hello')")?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -391,7 +338,7 @@ fn new_ignored_file() -> anyhow::Result<()> {

    std::fs::write(foo_path.as_std_path(), "print('Hello')")?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -413,7 +360,7 @@ fn changed_file() -> anyhow::Result<()> {

    update_file(&foo_path, "print('Version 2')")?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    assert!(!changes.is_empty());

@@ -438,7 +385,7 @@ fn deleted_file() -> anyhow::Result<()> {

    std::fs::remove_file(foo_path.as_std_path())?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -470,7 +417,7 @@ fn move_file_to_trash() -> anyhow::Result<()> {
        trash_path.join("foo.py").as_std_path(),
    )?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -502,7 +449,7 @@ fn move_file_to_workspace() -> anyhow::Result<()> {

    std::fs::rename(foo_path.as_std_path(), foo_in_workspace_path.as_std_path())?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -530,7 +477,7 @@ fn rename_file() -> anyhow::Result<()> {

    std::fs::rename(foo_path.as_std_path(), bar_path.as_std_path())?;

-    let changes = case.stop_watch(event_for_file("bar.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -574,7 +521,7 @@ fn directory_moved_to_workspace() -> anyhow::Result<()> {
    std::fs::rename(sub_original_path.as_std_path(), sub_new_path.as_std_path())
        .with_context(|| "Failed to move sub directory")?;

-    let changes = case.stop_watch(event_for_file("sub"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -633,7 +580,7 @@ fn directory_moved_to_trash() -> anyhow::Result<()> {
    std::fs::rename(sub_path.as_std_path(), trashed_sub.as_std_path())
        .with_context(|| "Failed to move the sub directory to the trash")?;

-    let changes = case.stop_watch(event_for_file("sub"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -657,6 +604,8 @@ fn directory_moved_to_trash() -> anyhow::Result<()> {

 #[test]
 fn directory_renamed() -> anyhow::Result<()> {
+    let _tracing = setup_logging_with_filter("file_watching=TRACE,red_knot=TRACE");
+
    let mut case = setup([
        ("bar.py", "import sub.a"),
        ("sub/__init__.py", ""),
@@ -695,8 +644,11 @@ fn directory_renamed() -> anyhow::Result<()> {
    std::fs::rename(sub_path.as_std_path(), foo_baz.as_std_path())
        .with_context(|| "Failed to move the sub directory")?;

-    // Linux and windows only emit an event for the newly created root directory, but not for every new component.
-    let changes = case.stop_watch(event_for_file("sub"));
+    let changes = case.stop_watch();
+
+    for event in &changes {
+        tracing::debug!("Event: {:?}", event);
+    }

    case.apply_changes(changes);

@@ -769,7 +721,7 @@ fn directory_deleted() -> anyhow::Result<()> {
    std::fs::remove_dir_all(sub_path.as_std_path())
        .with_context(|| "Failed to remove the sub directory")?;

-    let changes = case.stop_watch(event_for_file("sub"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -806,7 +758,7 @@ fn search_path() -> anyhow::Result<()> {

    std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;

-    let changes = case.stop_watch(event_for_file("a.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -837,7 +789,7 @@ fn add_search_path() -> anyhow::Result<()> {

    std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;

-    let changes = case.stop_watch(event_for_file("a.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -866,9 +818,9 @@ fn remove_search_path() -> anyhow::Result<()> {

    std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;

-    let changes = case.try_stop_watch(|_: &ChangeEvent| true, Duration::from_millis(100));
+    let changes = case.try_stop_watch(Duration::from_millis(100));

-    assert_eq!(changes, Err(vec![]));
+    assert_eq!(changes, None);

    Ok(())
 }
@@ -906,7 +858,7 @@ fn changed_versions_file() -> anyhow::Result<()> {
        "os: 3.0-",
    )?;

-    let changes = case.stop_watch(event_for_file("VERSIONS"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -959,7 +911,7 @@ fn hard_links_in_workspace() -> anyhow::Result<()> {
    // Write to the hard link target.
    update_file(foo_path, "print('Version 2')").context("Failed to update foo.py")?;

-    let changes = case.stop_watch(event_for_file("foo.py"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -1030,7 +982,7 @@ fn hard_links_to_target_outside_workspace() -> anyhow::Result<()> {
    // Write to the hard link target.
    update_file(foo_path, "print('Version 2')").context("Failed to update foo.py")?;

-    let changes = case.stop_watch(ChangeEvent::is_changed);
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -1069,7 +1021,7 @@ mod unix {
        )
        .with_context(|| "Failed to set file permissions.")?;

-        let changes = case.stop_watch(event_for_file("foo.py"));
+        let changes = case.stop_watch();

        case.apply_changes(changes);

@@ -1167,7 +1119,7 @@ mod unix {
        update_file(baz_workspace, "def baz(): print('Version 3')")
            .context("Failed to update bar/baz.py")?;

-        let changes = case.stop_watch(event_for_file("baz.py"));
+        let changes = case.stop_watch();

        case.apply_changes(changes);

@@ -1238,7 +1190,7 @@ mod unix {
        update_file(&patched_bar_baz, "def baz(): print('Version 2')")
            .context("Failed to update bar/baz.py")?;

-        let changes = case.stop_watch(event_for_file("baz.py"));
+        let changes = case.stop_watch();

        case.apply_changes(changes);

@@ -1346,7 +1298,7 @@ mod unix {
        update_file(&baz_original, "def baz(): print('Version 2')")
            .context("Failed to update bar/baz.py")?;

-        let changes = case.stop_watch(event_for_file("baz.py"));
+        let changes = case.stop_watch();

        case.apply_changes(changes);

@@ -1400,7 +1352,7 @@ fn nested_packages_delete_root() -> anyhow::Result<()> {

    std::fs::remove_file(case.workspace_path("pyproject.toml").as_std_path())?;

-    let changes = case.stop_watch(ChangeEvent::is_deleted);
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -1412,6 +1364,7 @@ fn nested_packages_delete_root() -> anyhow::Result<()> {

 #[test]
 fn added_package() -> anyhow::Result<()> {
+    let _ = setup_logging();
    let mut case = setup([
        (
            "pyproject.toml",
@@ -1453,7 +1406,7 @@ fn added_package() -> anyhow::Result<()> {
    )
    .context("failed to write pyproject.toml for package b")?;

-    let changes = case.stop_watch(event_for_file("pyproject.toml"));
+    let changes = case.stop_watch();

    case.apply_changes(changes);

@@ -1496,7 +1449,7 @@ fn removed_package() -> anyhow::Result<()> {
    std::fs::remove_dir_all(case.workspace_path("packages/b").as_std_path())
        .context("failed to remove package 'b'")?;

-    let changes = case.stop_watch(ChangeEvent::is_deleted);
+    let changes = case.stop_watch();

    case.apply_changes(changes);

--- a/crates/red_knot_python_semantic/Cargo.toml
+++ b/crates/red_knot_python_semantic/Cargo.toml
@@ -13,7 +13,6 @@ license = { workspace = true }
 [dependencies]
 ruff_db = { workspace = true }
 ruff_index = { workspace = true }
-ruff_macros = { workspace = true }
 ruff_python_ast = { workspace = true }
 ruff_python_parser = { workspace = true }
 ruff_python_stdlib = { workspace = true }
@@ -50,8 +49,6 @@ anyhow = { workspace = true }
 dir-test = { workspace = true }
 insta = { workspace = true }
 tempfile = { workspace = true }
-quickcheck = { version = "1.0.3", default-features = false }
-quickcheck_macros = { version = "1.0.0" }

 [lints]
 workspace = true
--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/any.md
@@ -1,83 +0,0 @@
-# Any
-
-## Annotation
-
-`typing.Any` is a way to name the Any type.
-
-```py
-from typing import Any
-
-x: Any = 1
-x = "foo"
-
-def f():
-    reveal_type(x)  # revealed: Any
-```
-
-## Aliased to a different name
-
-If you alias `typing.Any` to another name, we still recognize that as a spelling of the Any type.
-
-```py
-from typing import Any as RenamedAny
-
-x: RenamedAny = 1
-x = "foo"
-
-def f():
-    reveal_type(x)  # revealed: Any
-```
-
-## Shadowed class
-
-If you define your own class named `Any`, using that in a type expression refers to your class, and
-isn't a spelling of the Any type.
-
-```py
-class Any: ...
-
-x: Any
-
-def f():
-    reveal_type(x)  # revealed: Any
-
-# This verifies that we're not accidentally seeing typing.Any, since str is assignable
-# to that but not to our locally defined class.
-y: Any = "not an Any"  # error: [invalid-assignment]
-```
-
-## Subclass
-
-The spec allows you to define subclasses of `Any`.
-
-TODO: Handle assignments correctly. `Subclass` has an unknown superclass, which might be `int`. The
-assignment to `x` should not be allowed, even when the unknown superclass is `int`. The assignment
-to `y` should be allowed, since `Subclass` might have `int` as a superclass, and is therefore
-assignable to `int`.
-
-```py
-from typing import Any
-
-class Subclass(Any): ...
-
-reveal_type(Subclass.__mro__)  # revealed: tuple[Literal[Subclass], Any, Literal[object]]
-
-x: Subclass = 1  # error: [invalid-assignment]
-# TODO: no diagnostic
-y: int = Subclass()  # error: [invalid-assignment]
-
-def _(s: Subclass):
-    reveal_type(s)  # revealed: Subclass
-```
-
-## Invalid
-
-`Any` cannot be parameterized:
-
-```py
-from typing import Any
-
-# error: [invalid-type-parameter] "Type `typing.Any` expected no type parameter"
-def f(x: Any[int]):
-    reveal_type(x)  # revealed: Unknown
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/literal_string.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/literal_string.md
@@ -12,7 +12,7 @@ Parts of the testcases defined here were adapted from [the specification's examp
 It can be used anywhere a type is accepted:

 ```py
-from typing_extensions import LiteralString
+from typing import LiteralString

 x: LiteralString

@@ -25,7 +25,7 @@ def f():
 `LiteralString` cannot be used within `Literal`:

 ```py
-from typing_extensions import Literal, LiteralString
+from typing import Literal, LiteralString

 bad_union: Literal["hello", LiteralString]  # error: [invalid-literal-parameter]
 bad_nesting: Literal[LiteralString]  # error: [invalid-literal-parameter]
@@ -36,7 +36,7 @@ bad_nesting: Literal[LiteralString]  # error: [invalid-literal-parameter]
 `LiteralString` cannot be parametrized.

 ```py
-from typing_extensions import LiteralString
+from typing import LiteralString

 a: LiteralString[str]  # error: [invalid-type-parameter]
 b: LiteralString["foo"]  # error: [invalid-type-parameter]
@@ -47,7 +47,7 @@ b: LiteralString["foo"]  # error: [invalid-type-parameter]
 Subclassing `LiteralString` leads to a runtime error.

 ```py
-from typing_extensions import LiteralString
+from typing import LiteralString

 class C(LiteralString): ...  # error: [invalid-base]
 ```
@@ -57,8 +57,6 @@ class C(LiteralString): ...  # error: [invalid-base]
 ### Common operations

 ```py
-from typing_extensions import LiteralString
-
 foo: LiteralString = "foo"
 reveal_type(foo)  # revealed: Literal["foo"]

@@ -87,35 +85,33 @@ reveal_type(template.format(foo, bar))  # revealed: @Todo(call todo)
 vice versa.

 ```py
-from typing_extensions import Literal, LiteralString
+def coinflip() -> bool:
+    return True

-def _(flag: bool):
-    foo_1: Literal["foo"] = "foo"
-    bar_1: LiteralString = foo_1  # fine
+foo_1: Literal["foo"] = "foo"
+bar_1: LiteralString = foo_1  # fine

-    foo_2 = "foo" if flag else "bar"
-    reveal_type(foo_2)  # revealed: Literal["foo", "bar"]
-    bar_2: LiteralString = foo_2  # fine
+foo_2 = "foo" if coinflip() else "bar"
+reveal_type(foo_2)  # revealed: Literal["foo", "bar"]
+bar_2: LiteralString = foo_2  # fine

-    foo_3: LiteralString = "foo" * 1_000_000_000
-    bar_3: str = foo_2  # fine
+foo_3: LiteralString = "foo" * 1_000_000_000
+bar_3: str = foo_2  # fine

-    baz_1: str = str()
-    qux_1: LiteralString = baz_1  # error: [invalid-assignment]
+baz_1: str = str()
+qux_1: LiteralString = baz_1  # error: [invalid-assignment]

-    baz_2: LiteralString = "baz" * 1_000_000_000
-    qux_2: Literal["qux"] = baz_2  # error: [invalid-assignment]
+baz_2: LiteralString = "baz" * 1_000_000_000
+qux_2: Literal["qux"] = baz_2  # error: [invalid-assignment]

-    baz_3 = "foo" if flag else 1
-    reveal_type(baz_3)  # revealed: Literal["foo"] | Literal[1]
-    qux_3: LiteralString = baz_3  # error: [invalid-assignment]
+baz_3 = "foo" if coinflip() else 1
+reveal_type(baz_3)  # revealed: Literal["foo"] | Literal[1]
+qux_3: LiteralString = baz_3  # error: [invalid-assignment]
 ```

 ### Narrowing

 ```py
-from typing_extensions import LiteralString
-
 lorem: LiteralString = "lorem" * 1_000_000_000

 reveal_type(lorem)  # revealed: LiteralString
@@ -129,22 +125,4 @@ if "" < lorem == "ipsum":
    reveal_type(lorem)  # revealed: Literal["ipsum"]
 ```

-## `typing.LiteralString`
-
-`typing.LiteralString` is only available in Python 3.11 and later:
-
-```toml
-[environment]
-target-version = "3.11"
-```
-
-```py
-from typing import LiteralString
-
-x: LiteralString = "foo"
-
-def f():
-    reveal_type(x)  # revealed: LiteralString
-```
-
 [1]: https://typing.readthedocs.io/en/latest/spec/literal.html#literalstring
--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/never.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/never.md
@@ -19,11 +19,12 @@ reveal_type(stop())
 ## Assignment

 ```py
-from typing_extensions import NoReturn, Never, Any
+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
@@ -45,20 +46,17 @@ def f():
    v6: Never = 1
 ```

-## `typing.Never`
-
-`typing.Never` is only available in Python 3.11 and later:
-
-```toml
-[environment]
-target-version = "3.11"
-```
+## Typing Extensions

 ```py
-from typing import Never
+from typing_extensions import NoReturn, Never

-x: Never
+x: NoReturn
+y: Never

 def f():
-    reveal_type(x)  # revealed: Never
+    # revealed: Never
+    reveal_type(x)
+    # revealed: Never
+    reveal_type(y)
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/starred.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/starred.md
@@ -8,8 +8,8 @@ from typing_extensions import TypeVarTuple
 Ts = TypeVarTuple("Ts")

 def append_int(*args: *Ts) -> tuple[*Ts, int]:
-    # TODO: tuple[*Ts]
-    reveal_type(args)  # revealed: tuple
+    # TODO: should show some representation of the variadic generic type
+    reveal_type(args)  # revealed: @Todo(function parameter type)

    return (*args, 1)

--- a/crates/red_knot_python_semantic/resources/mdtest/annotations/string.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/annotations/string.md
@@ -3,56 +3,75 @@
 ## Simple

 ```py
-def f(v: "int"):
-    reveal_type(v)  # revealed: int
+def f() -> "int":
+    return 1
+
+reveal_type(f())  # revealed: int
 ```

 ## Nested

 ```py
-def f(v: "'int'"):
-    reveal_type(v)  # revealed: int
+def f() -> "'int'":
+    return 1
+
+reveal_type(f())  # revealed: int
 ```

 ## Type expression

 ```py
-def f1(v: "int | str", w: "tuple[int, str]"):
-    reveal_type(v)  # revealed: int | str
-    reveal_type(w)  # revealed: tuple[int, str]
+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(v: tuple[int, "str"]):
-    reveal_type(v)  # revealed: tuple[int, str]
+def f() -> tuple[int, "str"]:
+    return 1
+
+reveal_type(f())  # revealed: tuple[int, str]
 ```

 ## Deferred

 ```py
-def f(v: "Foo"):
-    reveal_type(v)  # revealed: Foo
+def f() -> "Foo":
+    return Foo()

-class Foo: ...
+class Foo:
+    pass
+
+reveal_type(f())  # revealed: Foo
 ```

 ## Deferred (undefined)

 ```py
 # error: [unresolved-reference]
-def f(v: "Foo"):
-    reveal_type(v)  # revealed: Unknown
+def f() -> "Foo":
+    pass
+
+reveal_type(f())  # revealed: Unknown
 ```

 ## Partial deferred

 ```py
-def f(v: int | "Foo"):
-    reveal_type(v)  # revealed: int | Foo
+def f() -> int | "Foo":
+    return 1

-class Foo: ...
+class Foo:
+    pass
+
+reveal_type(f())  # revealed: int | Foo
 ```

 ## `typing.Literal`
@@ -60,43 +79,65 @@ class Foo: ...
 ```py
 from typing import Literal

-def f1(v: Literal["Foo", "Bar"], w: 'Literal["Foo", "Bar"]'):
-    reveal_type(v)  # revealed: Literal["Foo", "Bar"]
-    reveal_type(w)  # revealed: Literal["Foo", "Bar"]
+def f1() -> Literal["Foo", "Bar"]:
+    return "Foo"

-class 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
-def f1(
-    # error: [raw-string-type-annotation] "Type expressions cannot use raw string literal"
-    a: r"int",
-    # error: [fstring-type-annotation] "Type expressions cannot use f-strings"
-    b: f"int",
-    # error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
-    c: b"int",
-    d: "int",
-    # error: [implicit-concatenated-string-type-annotation] "Type expressions cannot span multiple string literals"
-    e: "in" "t",
-    # error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
-    f: "\N{LATIN SMALL LETTER I}nt",
-    # error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
-    g: "\x69nt",
-    h: """int""",
-    # error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
-    i: "b'int'",
-):
-    reveal_type(a)  # revealed: Unknown
-    reveal_type(b)  # revealed: Unknown
-    reveal_type(c)  # revealed: Unknown
-    reveal_type(d)  # revealed: int
-    reveal_type(e)  # revealed: Unknown
-    reveal_type(f)  # revealed: Unknown
-    reveal_type(g)  # revealed: Unknown
-    reveal_type(h)  # revealed: int
-    reveal_type(i)  # revealed: Unknown
+# 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
+
+# error: [annotation-byte-string] "Type expressions cannot use bytes literal"
+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`
@@ -104,8 +145,10 @@ def f1(
 ```py
 from typing import Literal

-def f(v: Literal["a", r"b", b"c", "d" "e", "\N{LATIN SMALL LETTER F}", "\x67", """h"""]):
-    reveal_type(v)  # revealed: Literal["a", "b", "de", "f", "g", "h"] | Literal[b"c"]
+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
@@ -132,7 +175,8 @@ c: "Foo"
 # error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `Foo`"
 d: "Foo" = 1

-class Foo: ...
+class Foo:
+    pass

 c = Foo()

@@ -164,9 +208,9 @@ 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: [invalid-syntax-in-forward-annotation]
+# error: [forward-annotation-syntax-error]
 m: "yield 1"
-# error: [invalid-syntax-in-forward-annotation]
+# error: [forward-annotation-syntax-error]
 n: "yield from 1"
 o: "1 < 2"
 p: "call()"
--- a/crates/red_knot_python_semantic/resources/mdtest/assignment/annotations.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/assignment/annotations.md
@@ -50,7 +50,7 @@ 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: homogeneous tuples, PEP-646 tuples
+# 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)
@@ -78,10 +78,20 @@ c: tuple[str | int, str] = ([], "foo")
 ## PEP-604 annotations are supported

 ```py
-def foo(v: str | int | None, w: str | str | None, x: str | str):
-    reveal_type(v)  # revealed: str | int | None
-    reveal_type(w)  # revealed: str | None
-    reveal_type(x)  # revealed: str
+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
@@ -108,7 +118,8 @@ from __future__ import annotations

 x: Foo

-class Foo: ...
+class Foo:
+    pass

 x = Foo()
 reveal_type(x)  # revealed: Foo
@@ -119,7 +130,8 @@ reveal_type(x)  # revealed: Foo
 ```pyi path=main.pyi
 x: Foo

-class Foo: ...
+class Foo:
+    pass

 x = Foo()
 reveal_type(x)  # revealed: Foo
--- a/crates/red_knot_python_semantic/resources/mdtest/assignment/augmented.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/assignment/augmented.md
@@ -49,116 +49,134 @@ reveal_type(x)  # revealed: int
 ## Method union

 ```py
-def _(flag: bool):
-    class Foo:
-        if flag:
-            def __iadd__(self, other: int) -> str:
-                return "Hello, world!"
-        else:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True

-    f = Foo()
-    f += 12
+flag = bool_instance()

-    reveal_type(f)  # revealed: str | int
+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 _(flag: bool):
-    class Foo:
-        if flag:
-            def __iadd__(self, other: str) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True

-    f = Foo()
+class Foo:
+    if bool_instance():
+        def __iadd__(self, other: str) -> int:
+            return 42

-    # 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!"
+f = Foo()

-    reveal_type(f)  # revealed: int | Unknown
+# 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 _(flag: bool):
-    class Foo:
-        def __add__(self, other: str) -> str:
-            return "Hello, world!"
-        if flag:
-            def __iadd__(self, other: str) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True

-    f = Foo()
-    f += "Hello, world!"
+class Foo:
+    def __add__(self, other: str) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: str) -> int:
+            return 42

-    reveal_type(f)  # revealed: int | str
+f = Foo()
+f += "Hello, world!"
+
+reveal_type(f)  # revealed: int | str
 ```

 ## Partially bound target union

 ```py
-def _(flag1: bool, flag2: bool):
-    class Foo:
-        def __add__(self, other: int) -> str:
-            return "Hello, world!"
-        if flag1:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True

-    if flag2:
-        f = Foo()
-    else:
-        f = 42.0
-    f += 12
+class Foo:
+    def __add__(self, other: int) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: int) -> int:
+            return 42

-    reveal_type(f)  # revealed: int | str | float
+if bool_instance():
+    f = Foo()
+else:
+    f = 42.0
+f += 12
+
+reveal_type(f)  # revealed: int | str | float
 ```

 ## Target union

 ```py
-def _(flag: bool):
-    class Foo:
-        def __iadd__(self, other: int) -> str:
-            return "Hello, world!"
+def bool_instance() -> bool:
+    return True

-    if flag:
-        f = Foo()
-    else:
-        f = 42.0
-    f += 12
+flag = bool_instance()

-    reveal_type(f)  # revealed: str | float
+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 f(flag: bool, flag2: bool):
-    class Foo:
-        def __add__(self, other: int) -> str:
-            return "Hello, world!"
-        if flag:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True

-    class Bar:
-        def __add__(self, other: int) -> bytes:
-            return b"Hello, world!"
+flag = bool_instance()

-        def __iadd__(self, other: int) -> float:
-            return 42.0
+class Foo:
+    def __add__(self, other: int) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: int) -> int:
+            return 42

-    if flag2:
-        f = Foo()
-    else:
-        f = Bar()
-    f += 12
+class Bar:
+    def __add__(self, other: int) -> bytes:
+        return b"Hello, world!"

-    reveal_type(f)  # revealed: int | str | float
+    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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/assignment/unbound.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/assignment/unbound.md
@@ -18,3 +18,43 @@ Note: in this particular example, one could argue that the most likely error wou
 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"]
+```
--- a/crates/red_knot_python_semantic/resources/mdtest/attributes.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/attributes.md
@@ -3,23 +3,27 @@
 ## Union of attributes

 ```py
-def _(flag: bool):
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+if flag:
+    class C1:
+        x = 1
+
+else:
+    class C1:
+        x = 2
+
+class C2:
    if flag:
-        class C1:
-            x = 1
-
+        x = 3
    else:
-        class C1:
-            x = 2
+        x = 4

-    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]
+reveal_type(C1.x)  # revealed: Literal[1, 2]
+reveal_type(C2.x)  # revealed: Literal[3, 4]
 ```

 ## Inherited attributes
@@ -64,19 +68,24 @@ reveal_type(A.X)  # revealed: Literal[42]
 In this example, the `x` attribute is not defined in the `C2` element of the union:

 ```py
-def _(flag1: bool, flag2: bool):
-    class C1:
-        x = 1
+def bool_instance() -> bool:
+    return True

-    class C2: ...
+class C1:
+    x = 1

-    class C3:
-        x = 3
+class C2: ...

-    C = C1 if flag1 else C2 if flag2 else C3
+class C3:
+    x = 3

-    # error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-    reveal_type(C.x)  # revealed: Literal[1, 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
@@ -85,21 +94,26 @@ We raise the same diagnostic if the attribute is possibly-unbound in at least on
 union:

 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    class C1:
-        x = 1
+def bool_instance() -> bool:
+    return True

-    class C2:
-        if flag:
-            x = 2
+class C1:
+    x = 1

-    class C3:
-        x = 3
+class C2:
+    if bool_instance():
+        x = 2

-    C = C1 if flag1 else C2 if flag2 else C3
+class C3:
+    x = 3

-    # error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-    reveal_type(C.x)  # revealed: Literal[1, 2, 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
@@ -107,51 +121,16 @@ def _(flag: bool, flag1: bool, flag2: bool):
 If the symbol is unbound in all elements of the union, we detect that:

 ```py
-def _(flag: bool):
-    class C1: ...
-    class C2: ...
-    C = C1 if flag else C2
+def bool_instance() -> bool:
+    return True

-    # error: [unresolved-attribute] "Type `Literal[C1, C2]` has no attribute `x`"
-    reveal_type(C.x)  # revealed: Unknown
-```
-
-## Objects of all types have a `__class__` method
-
-```py
-import typing_extensions
-
-reveal_type(typing_extensions.__class__)  # revealed: Literal[ModuleType]
-
-a = 42
-reveal_type(a.__class__)  # revealed: Literal[int]
-
-b = "42"
-reveal_type(b.__class__)  # revealed: Literal[str]
-
-c = b"42"
-reveal_type(c.__class__)  # revealed: Literal[bytes]
-
-d = True
-reveal_type(d.__class__)  # revealed: Literal[bool]
-
-e = (42, 42)
-reveal_type(e.__class__)  # revealed: Literal[tuple]
-
-def f(a: int, b: typing_extensions.LiteralString, c: int | str, d: type[str]):
-    reveal_type(a.__class__)  # revealed: type[int]
-    reveal_type(b.__class__)  # revealed: Literal[str]
-    reveal_type(c.__class__)  # revealed: type[int] | type[str]
-
-    # `type[type]`, a.k.a., either the class `type` or some subclass of `type`.
-    # It would be incorrect to infer `Literal[type]` here,
-    # as `c` could be some subclass of `str` with a custom metaclass.
-    # All we know is that the metaclass must be a (non-strict) subclass of `type`.
-    reveal_type(d.__class__)  # revealed: type[type]
-
-reveal_type(f.__class__)  # revealed: Literal[FunctionType]
-
-class Foo: ...
-
-reveal_type(Foo.__class__)  # revealed: Literal[type]
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/binary/instances.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/binary/instances.md
@@ -281,12 +281,20 @@ 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 _(x: bool, y: int):
-    reveal_type(x + y)  # revealed: int
-    reveal_type(4.2 + x)  # revealed: float
+def returns_int() -> int:
+    return 42

-    # TODO should be float, need to check arg type and fall back to `rhs.__radd__`
-    reveal_type(y + 4.12)  # revealed: int
+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
--- a/crates/red_knot_python_semantic/resources/mdtest/boolean/short_circuit.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/boolean/short_circuit.md
@@ -7,25 +7,29 @@ Similarly, in `and` expressions, if the left-hand side is falsy, the right-hand
 evaluated.

 ```py
-def _(flag: bool):
-    if flag or (x := 1):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True

-    if flag and (x := 1):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
+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 _(flag: bool):
-    if (x := 1) or flag:
-        reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True

-    if (x := 1) and flag:
-        reveal_type(x)  # revealed: Literal[1]
+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
@@ -45,26 +49,30 @@ if True and (x := 1):
 ## Later expressions can always use variables from earlier expressions

 ```py
-def _(flag: bool):
-    flag or (x := 1) or reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True

-    # error: [unresolved-reference]
-    flag or reveal_type(y) or (y := 1)  # revealed: Unknown
+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 _(flag1: bool, flag2: bool):
-    if flag1 or ((x := 1) and flag2):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
-
-    if ((y := 1) and flag1) or flag2:
-        reveal_type(y)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True

+if bool_instance() or ((x := 1) and bool_instance()):
    # error: [possibly-unresolved-reference]
-    if (flag1 and (z := 1)) or reveal_type(z):  # revealed: Literal[1]
-        # error: [possibly-unresolved-reference]
-        reveal_type(z)  # revealed: Literal[1]
+    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]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/call/callable_instance.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/call/callable_instance.md
@@ -22,27 +22,29 @@ reveal_type(b)  # revealed: Unknown
 ## Possibly unbound `__call__` method

 ```py
-def _(flag: bool):
-    class PossiblyNotCallable:
-        if flag:
-            def __call__(self) -> int: ...
+def flag() -> bool: ...

-    a = PossiblyNotCallable()
-    result = a()  # error: "Object of type `PossiblyNotCallable` is not callable (possibly unbound `__call__` method)"
-    reveal_type(result)  # revealed: int
+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: ...
+def flag() -> bool: ...

-    # error: [possibly-unresolved-reference]
-    a = PossiblyUnbound()
-    reveal_type(a())  # revealed: int
+if flag():
+    class PossiblyUnbound:
+        def __call__(self) -> int: ...
+
+# error: [possibly-unresolved-reference]
+a = PossiblyUnbound()
+reveal_type(a())  # revealed: int
 ```

 ## Non-callable `__call__`
@@ -59,14 +61,15 @@ reveal_type(a())  # revealed: Unknown
 ## Possibly non-callable `__call__`

 ```py
-def _(flag: bool):
-    class NonCallable:
-        if flag:
-            __call__ = 1
-        else:
-            def __call__(self) -> int: ...
+def flag() -> bool: ...

-    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
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/call/function.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/call/function.md
@@ -57,10 +57,12 @@ 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
+def flag() -> bool: ...
+
+if flag():
+    def foo() -> int:
+        return 42
+
+# error: [possibly-unresolved-reference]
+reveal_type(foo())  # revealed: int
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/call/union.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/call/union.md
@@ -3,14 +3,22 @@
 ## Union of return types

 ```py
-def _(flag: bool):
-    if flag:
-        def f() -> int:
-            return 1
-    else:
-        def f() -> str:
-            return "foo"
-    reveal_type(f())  # revealed: int | str
+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
@@ -18,10 +26,13 @@ def _(flag: bool):
 ```py
 from nonexistent import f  # error: [unresolved-import] "Cannot resolve import `nonexistent`"

-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
+flag = bool_instance()
+
+if flag:
+
    def f() -> int:
        return 1

@@ -33,14 +44,20 @@ reveal_type(f())  # revealed: Unknown | int
 Calling a union with a non-callable element should emit a diagnostic.

 ```py
-def _(flag: bool):
-    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
+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
@@ -48,17 +65,23 @@ def _(flag: bool):
 Calling a union with multiple non-callable elements should mention all of them in the diagnostic.

 ```py
-def _(flag: bool, flag2: bool):
-    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())
+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
@@ -66,12 +89,16 @@ def _(flag: bool, flag2: bool):
 Calling a union with no callable elements can emit a simpler diagnostic.

 ```py
-def _(flag: bool):
-    if flag:
-        f = 1
-    else:
-        f = "foo"
+def bool_instance() -> bool:
+    return True

-    x = f()  # error: "Object of type `Literal[1] | Literal["foo"]` is not callable"
-    reveal_type(x)  # revealed: Unknown
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/identity.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/identity.md
@@ -3,31 +3,38 @@
 ```py
 class A: ...

-def _(a1: A, a2: A, o: object):
-    n1 = None
-    n2 = None
+def get_a() -> A: ...
+def get_object() -> object: ...

-    reveal_type(a1 is a1)  # revealed: bool
-    reveal_type(a1 is a2)  # revealed: bool
+a1 = get_a()
+a2 = get_a()

-    reveal_type(n1 is n1)  # revealed: Literal[True]
-    reveal_type(n1 is n2)  # revealed: Literal[True]
+n1 = None
+n2 = None

-    reveal_type(a1 is n1)  # revealed: Literal[False]
-    reveal_type(n1 is a1)  # revealed: Literal[False]
+o = get_object()

-    reveal_type(a1 is o)  # revealed: bool
-    reveal_type(n1 is o)  # revealed: bool
+reveal_type(a1 is a1)  # revealed: bool
+reveal_type(a1 is a2)  # revealed: bool

-    reveal_type(a1 is not a1)  # revealed: bool
-    reveal_type(a1 is not a2)  # revealed: bool
+reveal_type(n1 is n1)  # revealed: Literal[True]
+reveal_type(n1 is n2)  # revealed: Literal[True]

-    reveal_type(n1 is not n1)  # revealed: Literal[False]
-    reveal_type(n1 is not n2)  # revealed: Literal[False]
+reveal_type(a1 is n1)  # revealed: Literal[False]
+reveal_type(n1 is a1)  # 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 o)  # revealed: bool
+reveal_type(n1 is o)  # revealed: bool

-    reveal_type(a1 is not o)  # revealed: bool
-    reveal_type(n1 is not 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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/instances/rich_comparison.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/instances/rich_comparison.md
@@ -312,9 +312,17 @@ reveal_type(1 <= 2j)  # revealed: bool
 reveal_type(1 > 2j)  # revealed: bool
 reveal_type(1 >= 2j)  # revealed: bool

-def f(x: bool, y: int):
-    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
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/integers.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/integers.md
@@ -20,8 +20,10 @@ reveal_type(1 <= "" and 0 < 1)  # revealed: bool

 ```py
 # TODO: implement lookup of `__eq__` on typeshed `int` stub.
-def _(a: int, b: int):
-    reveal_type(1 == a)  # revealed: bool
-    reveal_type(9 < a)  # revealed: bool
-    reveal_type(a < b)  # revealed: bool
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/intersections.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/intersections.md
@@ -14,19 +14,21 @@ class Child1(Base):

 class Child2(Base): ...

-def _(x: Base):
-    c1 = Child1()
+def get_base() -> Base: ...

-    # Create an intersection type through narrowing:
-    if isinstance(x, Child1):
-        if isinstance(x, Child2):
-            reveal_type(x)  # revealed: Child1 & Child2
+x = get_base()
+c1 = Child1()

-            reveal_type(x == 1)  # revealed: Literal[True]
+# Create an intersection type through narrowing:
+if isinstance(x, Child1):
+    if isinstance(x, Child2):
+        reveal_type(x)  # revealed: Child1 & Child2

-            # Other comparison operators fall back to the base type:
-            reveal_type(x > 1)  # revealed: bool
-            reveal_type(x is c1)  # revealed: bool
+        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
@@ -71,15 +73,18 @@ if x != "abc":
 #### Integers

 ```py
-def _(x: int):
-    if x != 1:
-        reveal_type(x)  # revealed: int & ~Literal[1]
+def get_int() -> int: ...

-        reveal_type(x != 1)  # revealed: Literal[True]
-        reveal_type(x != 2)  # revealed: bool
+x = get_int()

-        reveal_type(x == 1)  # revealed: Literal[False]
-        reveal_type(x == 2)  # revealed: bool
+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
@@ -87,15 +92,18 @@ def _(x: int):
 ```py
 class A: ...

-def _(o: object):
-    a = A()
-    n = None
+def get_object() -> object: ...

-    if o is not None:
-        reveal_type(o)  # revealed: object & ~None
+o = object()

-        reveal_type(o is n)  # revealed: Literal[False]
-        reveal_type(o is not n)  # revealed: Literal[True]
+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
@@ -111,13 +119,16 @@ class Container:

 class NonContainer: ...

-def _(x: object):
-    if isinstance(x, Container):
-        if isinstance(x, NonContainer):
-            reveal_type(x)  # revealed: Container & NonContainer
+def get_object() -> object: ...

-            # error: [unsupported-operator] "Operator `in` is not supported for types `int` and `NonContainer`"
-            reveal_type(2 in x)  # revealed: bool
+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
@@ -131,11 +142,14 @@ class Container:

 class NonContainer: ...

-def _(x: object):
-    if isinstance(x, Container):
-        if not isinstance(x, NonContainer):
-            reveal_type(x)  # revealed: Container & ~NonContainer
+def get_object() -> object: ...

-            # No error here!
-            reveal_type(2 in x)  # revealed: bool
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/strings.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/strings.md
@@ -3,17 +3,18 @@
 ## String literals

 ```py
-def _(x: 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(x < "...")  # revealed: bool
+def str_instance() -> str: ...

-    # ensure we're not comparing the interned salsa symbols, which compare by order of declaration.
-    reveal_type("ab" < "ab_cd")  # revealed: Literal[True]
+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]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/tuples.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/tuples.md
@@ -58,23 +58,28 @@ reveal_type(c >= d)  # revealed: Literal[True]
 #### Results with Ambiguity

 ```py
-def _(x: bool, y: int):
-    a = (x,)
-    b = (y,)
+def bool_instance() -> bool:
+    return True

-    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
+def int_instance() -> int:
+    return 42

-    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
+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
@@ -192,7 +197,7 @@ 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")`
+> 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
@@ -203,38 +208,42 @@ In contrast, with operators like `<` and `>`, the comparison must consider each
 sequentially, and the final outcome might remain ambiguous until all pairs are compared.

 ```py
-def _(x: str, y: int):
-    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((y, "foo") == (y, "bar"))  # revealed: Literal[False]
+def str_instance() -> str:
+    return "hello"

-    a = (x, y, "foo")
+def int_instance() -> int:
+    return 42

-    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("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]

-    b = (x, y, "bar")
+a = (str_instance(), int_instance(), "foo")

-    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
+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

-    c = (x, y, "foo", "different_length")
+b = (str_instance(), int_instance(), "bar")

-    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
+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
@@ -243,36 +252,42 @@ Errors occurring within a tuple comparison should propagate outward. However, if
 comparison can clearly conclude before encountering an error, the error should not be raised.

 ```py
-def _(n: int, s: str):
-    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()
+def int_instance() -> int:
+    return 42

-    a = (0, n, A())
+def str_instance() -> str:
+    return "hello"

-    # 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
+class A: ...

-    # Comparison between `a` and `b` should only involve the first elements, `Literal[0]` and `Literal[99999]`,
-    # and should terminate immediately.
-    b = (99999, n, 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()

-    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]
+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
@@ -280,20 +295,22 @@ def _(n: int, s: str):
 "Membership Test Comparisons" refers to the operators `in` and `not in`.

 ```py
-def _(n: int):
-    a = (1, 2)
-    b = ((3, 4), (1, 2))
-    c = ((1, 2, 3), (4, 5, 6))
-    d = ((n, n), (n, n))
+def int_instance() -> int:
+    return 42

-    reveal_type(a in b)  # revealed: Literal[True]
-    reveal_type(a not in b)  # revealed: Literal[False]
+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 c)  # revealed: Literal[False]
-    reveal_type(a not in c)  # revealed: Literal[True]
+reveal_type(a in b)  # revealed: Literal[True]
+reveal_type(a not in b)  # revealed: Literal[False]

-    reveal_type(a in d)  # revealed: bool
-    reveal_type(a not in d)  # revealed: bool
+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
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/unions.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/unions.md
@@ -5,46 +5,49 @@
 Comparisons on union types need to consider all possible cases:

 ```py
-def _(flag: bool):
-    one_or_two = 1 if flag else 2
+def bool_instance() -> bool:
+    return True

-    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]
+flag = bool_instance()
+one_or_two = 1 if flag else 2

-    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 <= 2)  # revealed: Literal[True]
+reveal_type(one_or_two <= 1)  # revealed: bool
+reveal_type(one_or_two <= 0)  # 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(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 > 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 < 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 == 3)  # revealed: Literal[False]
-    reveal_type(one_or_two == 1)  # revealed: bool
+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[True]
-    reveal_type(one_or_two != 1)  # revealed: bool
+reveal_type(one_or_two == 3)  # revealed: Literal[False]
+reveal_type(one_or_two == 1)  # revealed: bool

-    a_or_ab = "a" if flag else "ab"
+reveal_type(one_or_two != 3)  # revealed: Literal[True]
+reveal_type(one_or_two != 1)  # revealed: bool

-    reveal_type(a_or_ab in "ab")  # revealed: Literal[True]
-    reveal_type("a" in a_or_ab)  # revealed: Literal[True]
+a_or_ab = "a" if flag else "ab"

-    reveal_type("c" not in a_or_ab)  # revealed: Literal[True]
-    reveal_type("a" not in a_or_ab)  # revealed: Literal[False]
+reveal_type(a_or_ab in "ab")  # revealed: Literal[True]
+reveal_type("a" in a_or_ab)  # revealed: Literal[True]

-    reveal_type("b" in a_or_ab)  # revealed: bool
-    reveal_type("b" not in a_or_ab)  # revealed: bool
+reveal_type("c" not in a_or_ab)  # revealed: Literal[True]
+reveal_type("a" not in a_or_ab)  # revealed: Literal[False]

-    one_or_none = 1 if flag else None
+reveal_type("b" in a_or_ab)  # revealed: bool
+reveal_type("b" not in a_or_ab)  # revealed: bool

-    reveal_type(one_or_none is None)  # revealed: bool
-    reveal_type(one_or_none is not None)  # 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
@@ -53,15 +56,18 @@ With unions on both sides, we need to consider the full cross product of options
 resulting (union) type:

 ```py
-def _(flag_s: bool, flag_l: bool):
-    small = 1 if flag_s else 2
-    large = 2 if flag_l else 3
+def bool_instance() -> bool:
+    return True

-    reveal_type(small <= large)  # revealed: Literal[True]
-    reveal_type(small >= large)  # revealed: bool
+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: bool
-    reveal_type(small > large)  # revealed: Literal[False]
+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
@@ -71,9 +77,12 @@ back to `bool` for the result type instead of trying to infer something more pre
 (supported) variants:

 ```py
-def _(flag: bool):
-    x = [1, 2] if flag else 1
+def bool_instance() -> bool:
+    return True

-    result = 1 in x  # error: "Operator `in` is not supported"
-    reveal_type(result)  # revealed: bool
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/comparison/unsupported.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/comparison/unsupported.md
@@ -1,38 +1,42 @@
 # Comparison: Unsupported operators

 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    class A: ...
-    a = 1 in 7  # error: "Operator `in` is not supported for types `Literal[1]` and `Literal[7]`"
-    reveal_type(a)  # revealed: bool
+def bool_instance() -> bool:
+    return True

-    b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
-    reveal_type(b)  # revealed: bool
+class A: ...

-    # 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
+a = 1 in 7  # error: "Operator `in` is not supported for types `Literal[1]` and `Literal[7]`"
+reveal_type(a)  # 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
+b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
+reveal_type(b)  # revealed: bool

-    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, 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, 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
+# 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

-    # error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[bool, A]` with `tuple[bool, A]`"
-    g = (flag1, A()) < (flag2, A())
-    reveal_type(g)  # revealed: Unknown
+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
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/conditional/if_expression.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/conditional/if_expression.md
@@ -3,35 +3,47 @@
 ## Simple if-expression

 ```py
-def _(flag: bool):
-    x = 1 if flag else 2
-    reveal_type(x)  # revealed: Literal[1, 2]
+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 _(flag: bool):
-    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]
+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 _(flag: bool, flag2: bool):
-    x = 1 if flag else 2 if flag2 else 3
-    reveal_type(x)  # revealed: Literal[1, 2, 3]
+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 _(flag: bool):
-    x = 1 if flag else None
-    reveal_type(x)  # revealed: Literal[1] | None
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+x = 1 if flag else None
+reveal_type(x)  # revealed: Literal[1] | None
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/conditional/if_statement.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/conditional/if_statement.md
@@ -3,115 +3,128 @@
 ## Simple if

 ```py
-def _(flag: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True

-    if flag:
-        y = 3
+flag = bool_instance()
+y = 1
+y = 2

-    reveal_type(y)  # revealed: Literal[2, 3]
+if flag:
+    y = 3
+
+reveal_type(y)  # revealed: Literal[2, 3]
 ```

 ## Simple if-elif-else

 ```py
-def _(flag: bool, flag2: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True

-    if flag:
-        y = 3
-    elif flag2:
-        y = 4
-    else:
-        r = y
-        y = 5
-        s = y
-    x = y
+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]
+reveal_type(x)  # revealed: Literal[3, 4, 5]

-    # revealed: Literal[2]
-    # error: [possibly-unresolved-reference]
-    reveal_type(r)
+# revealed: Literal[2]
+# error: [possibly-unresolved-reference]
+reveal_type(r)

-    # revealed: Literal[5]
-    # error: [possibly-unresolved-reference]
-    reveal_type(s)
+# revealed: Literal[5]
+# error: [possibly-unresolved-reference]
+reveal_type(s)
 ```

 ## Single symbol across if-elif-else

 ```py
-def _(flag: bool, flag2: bool):
-    if flag:
-        y = 1
-    elif flag2:
-        y = 2
-    else:
-        y = 3
+def bool_instance() -> bool:
+    return True

-    reveal_type(y)  # revealed: Literal[1, 2, 3]
+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 _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True

-    if flag:
-        y = 1
-    elif flag2:
-        y = 2
-    else:
-        pass
-
-    reveal_type(y)  # revealed: Literal[0, 1, 2]
+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 _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True

-    if flag:
-        y = 1
-        z = 3
-    elif flag2:
-        y = 2
-    else:
-        pass
-
-    reveal_type(y)  # revealed: Literal[0, 1, 2]
+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 _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True

-    if flag:
-        if flag2:
-            y = 1
-
-    reveal_type(y)  # revealed: Literal[0, 1]
+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 _(flag: bool, flag2: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True

-    if flag:
-        y = 3
-    elif flag2:
-        y = 4
+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]
+reveal_type(y)  # revealed: Literal[2, 3, 4]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/conditional/match.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/conditional/match.md
@@ -31,7 +31,6 @@ reveal_type(y)
 ```py
 y = 1
 y = 2
-
 match 0:
    case 1:
        y = 3
--- a/crates/red_knot_python_semantic/resources/mdtest/declaration/error.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/declaration/error.md
@@ -10,35 +10,42 @@ x: str  # error: [invalid-declaration] "Cannot declare type `str` for inferred t
 ## Incompatible declarations

 ```py
-def _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True

-    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
+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 _(flag: bool):
-    if flag:
-        x: int
+def bool_instance() -> bool:
+    return True

-    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: Unknown, int"
+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 _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True

-    # error: [conflicting-declarations]
-    # error: [invalid-assignment]
-    x = b"foo"
+flag = bool_instance()
+if flag:
+    x: str
+else:
+    x: int
+
+# error: [conflicting-declarations]
+# error: [invalid-assignment]
+x = b"foo"
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/exception/basic.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/exception/basic.md
@@ -49,44 +49,12 @@ def foo(
    try:
        help()
    except x as e:
-        reveal_type(e)  # revealed: AttributeError
+        # TODO: should be `AttributeError`
+        reveal_type(e)  # revealed: @Todo(exception type)
    except y as f:
-        reveal_type(f)  # revealed: OSError | RuntimeError
+        # 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(full tuple[...] support)
-```
-
-## Invalid exception handlers
-
-```py
-try:
-    pass
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal[3]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-except 3 as e:
-    reveal_type(e)  # revealed: Unknown
-
-try:
-    pass
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal["foo"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal[b"bar"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-except (ValueError, OSError, "foo", b"bar") as e:
-    reveal_type(e)  # revealed: ValueError | OSError | Unknown
-
-def foo(
-    x: type[str],
-    y: tuple[type[OSError], type[RuntimeError], int],
-    z: tuple[type[str], ...],
-):
-    try:
-        help()
-    # error: [invalid-exception-caught]
-    except x as e:
-        reveal_type(e)  # revealed: Unknown
-    # error: [invalid-exception-caught]
-    except y as f:
-        reveal_type(f)  # revealed: OSError | RuntimeError | Unknown
-    except z as g:
-        # TODO: should emit a diagnostic here:
-        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+        reveal_type(g)  # revealed: @Todo(exception type)
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/exception/except_star.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/exception/except_star.md
@@ -1,59 +1,30 @@
-# `except*`
+# Except star

-## `except*` with `BaseException`
+## Except\* with BaseException

 ```py
 try:
    help()
 except* BaseException as e:
-    # TODO: should be `BaseExceptionGroup[BaseException]` --Alex
    reveal_type(e)  # revealed: BaseExceptionGroup
 ```

-## `except*` with specific exception
+## Except\* with specific exception

 ```py
 try:
    help()
 except* OSError as e:
-    # TODO: more precise would be `ExceptionGroup[OSError]` --Alex
-    # (needs homogenous tuples + generics)
+    # TODO(Alex): more precise would be `ExceptionGroup[OSError]`
    reveal_type(e)  # revealed: BaseExceptionGroup
 ```

-## `except*` with multiple exceptions
+## Except\* with multiple exceptions

 ```py
 try:
    help()
 except* (TypeError, AttributeError) as e:
-    # TODO: more precise would be `ExceptionGroup[TypeError | AttributeError]` --Alex
-    # (needs homogenous tuples + generics)
-    reveal_type(e)  # revealed: BaseExceptionGroup
-```
-
-## `except*` with mix of `Exception`s and `BaseException`s
-
-```py
-try:
-    help()
-except* (KeyboardInterrupt, AttributeError) as e:
-    # TODO: more precise would be `BaseExceptionGroup[KeyboardInterrupt | AttributeError]` --Alex
-    reveal_type(e)  # revealed: BaseExceptionGroup
-```
-
-## Invalid `except*` handlers
-
-```py
-try:
-    help()
-except* 3 as e:  # error: [invalid-exception-caught]
-    # TODO: Should be `BaseExceptionGroup[Unknown]` --Alex
-    reveal_type(e)  # revealed: BaseExceptionGroup
-
-try:
-    help()
-except* (AttributeError, 42) as e:  # error: [invalid-exception-caught]
-    # TODO: Should be `BaseExceptionGroup[AttributeError | Unknown]` --Alex
+    # TODO(Alex): more precise would be `ExceptionGroup[TypeError | AttributeError]`.
    reveal_type(e)  # revealed: BaseExceptionGroup
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/exception/invalid_syntax.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/exception/invalid_syntax.md
@@ -9,4 +9,5 @@ try:
    print
 except as e:  # error: [invalid-syntax]
    reveal_type(e)  # revealed: Unknown
+
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/expression/attribute.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/expression/attribute.md
@@ -3,25 +3,26 @@
 ## Boundness

 ```py
-def _(flag: bool):
-    class A:
-        always_bound = 1
+def flag() -> bool: ...

-        if flag:
-            union = 1
-        else:
-            union = "abc"
+class A:
+    always_bound = 1

-        if flag:
-            possibly_unbound = "abc"
+    if flag():
+        union = 1
+    else:
+        union = "abc"

-    reveal_type(A.always_bound)  # revealed: Literal[1]
+    if flag():
+        possibly_unbound = "abc"

-    reveal_type(A.union)  # revealed: Literal[1] | Literal["abc"]
+reveal_type(A.always_bound)  # revealed: Literal[1]

-    # error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
-    reveal_type(A.possibly_unbound)  # revealed: Literal["abc"]
+reveal_type(A.union)  # revealed: Literal[1] | Literal["abc"]

-    # error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
-    reveal_type(A.non_existent)  # revealed: Unknown
+# error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
+reveal_type(A.possibly_unbound)  # revealed: Literal["abc"]
+
+# error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
+reveal_type(A.non_existent)  # revealed: Unknown
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/expression/boolean.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/expression/boolean.md
@@ -3,45 +3,54 @@
 ## OR

 ```py
-def _(foo: str):
-    reveal_type(True or False)  # revealed: Literal[True]
-    reveal_type("x" or "y" or "z")  # revealed: Literal["x"]
-    reveal_type("" or "y" or "z")  # revealed: Literal["y"]
-    reveal_type(False or "z")  # revealed: Literal["z"]
-    reveal_type(False or True)  # revealed: Literal[True]
-    reveal_type(False or False)  # revealed: Literal[False]
-    reveal_type(foo or False)  # revealed: str | Literal[False]
-    reveal_type(foo or True)  # revealed: str | Literal[True]
+def foo() -> str:
+    pass
+
+reveal_type(True or False)  # revealed: Literal[True]
+reveal_type("x" or "y" or "z")  # revealed: Literal["x"]
+reveal_type("" or "y" or "z")  # revealed: Literal["y"]
+reveal_type(False or "z")  # revealed: Literal["z"]
+reveal_type(False or True)  # revealed: Literal[True]
+reveal_type(False or False)  # revealed: Literal[False]
+reveal_type(foo() or False)  # revealed: str | Literal[False]
+reveal_type(foo() or True)  # revealed: str | Literal[True]
 ```

 ## AND

 ```py
-def _(foo: str):
-    reveal_type(True and False)  # revealed: Literal[False]
-    reveal_type(False and True)  # revealed: Literal[False]
-    reveal_type(foo and False)  # revealed: str | Literal[False]
-    reveal_type(foo and True)  # revealed: str | Literal[True]
-    reveal_type("x" and "y" and "z")  # revealed: Literal["z"]
-    reveal_type("x" and "y" and "")  # revealed: Literal[""]
-    reveal_type("" and "y")  # revealed: Literal[""]
+def foo() -> str:
+    pass
+
+reveal_type(True and False)  # revealed: Literal[False]
+reveal_type(False and True)  # revealed: Literal[False]
+reveal_type(foo() and False)  # revealed: str | Literal[False]
+reveal_type(foo() and True)  # revealed: str | Literal[True]
+reveal_type("x" and "y" and "z")  # revealed: Literal["z"]
+reveal_type("x" and "y" and "")  # revealed: Literal[""]
+reveal_type("" and "y")  # revealed: Literal[""]
 ```

 ## Simple function calls to bool

 ```py
-def _(flag: bool):
-    if flag:
-        x = True
-    else:
-        x = False
+def returns_bool() -> bool:
+    return True

-    reveal_type(x)  # revealed: bool
+if returns_bool():
+    x = True
+else:
+    x = False
+
+reveal_type(x)  # revealed: bool
 ```

 ## Complex

 ```py
+def foo() -> str:
+    pass
+
 reveal_type("x" and "y" or "z")  # revealed: Literal["y"]
 reveal_type("x" or "y" and "z")  # revealed: Literal["x"]
 reveal_type("" and "y" or "z")  # revealed: Literal["z"]
--- a/crates/red_knot_python_semantic/resources/mdtest/expression/if.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/expression/if.md
@@ -3,8 +3,10 @@
 ## Union

 ```py
-def _(flag: bool):
-    reveal_type(1 if flag else 2)  # revealed: Literal[1, 2]
+def bool_instance() -> bool:
+    return True
+
+reveal_type(1 if bool_instance() else 2)  # revealed: Literal[1, 2]
 ```

 ## Statically known branches
@@ -28,12 +30,14 @@ reveal_type(1 if 0 else 2)  # revealed: Literal[2]
 The test inside an if expression should not affect code outside of the expression.

 ```py
-def _(flag: bool):
-    x: Literal[42, "hello"] = 42 if flag else "hello"
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+x: Literal[42, "hello"] = 42 if bool_instance() else "hello"

-    _ = ... if isinstance(x, str) else ...
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]

-    reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+_ = ... if isinstance(x, str) else ...
+
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/expression/len.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/expression/len.md
@@ -1,218 +0,0 @@
-# Length (`len()`)
-
-## Literal and constructed iterables
-
-### Strings and bytes literals
-
-```py
-reveal_type(len("no\rmal"))  # revealed: Literal[6]
-reveal_type(len(r"aw stri\ng"))  # revealed: Literal[10]
-reveal_type(len(r"conca\t" "ena\tion"))  # revealed: Literal[14]
-reveal_type(len(b"ytes lite" rb"al"))  # revealed: Literal[11]
-reveal_type(len("𝒰𝕹🄸©🕲𝕕ℇ"))  # revealed: Literal[7]
-
-reveal_type(  # revealed: Literal[7]
-    len(
-        """foo
-bar"""
-    )
-)
-reveal_type(  # revealed: Literal[9]
-    len(
-        r"""foo\r
-bar"""
-    )
-)
-reveal_type(  # revealed: Literal[7]
-    len(
-        b"""foo
-bar"""
-    )
-)
-reveal_type(  # revealed: Literal[9]
-    len(
-        rb"""foo\r
-bar"""
-    )
-)
-```
-
-### Tuples
-
-```py
-reveal_type(len(()))  # revealed: Literal[0]
-reveal_type(len((1,)))  # revealed: Literal[1]
-reveal_type(len((1, 2)))  # revealed: Literal[2]
-
-# TODO: Handle constructor calls
-reveal_type(len(tuple()))  # revealed: int
-
-# TODO: Handle star unpacks; Should be: Literal[0]
-reveal_type(len((*[],)))  # revealed: Literal[1]
-
-# TODO: Handle star unpacks; Should be: Literal[1]
-reveal_type(  # revealed: Literal[2]
-    len(
-        (
-            *[],
-            1,
-        )
-    )
-)
-
-# TODO: Handle star unpacks; Should be: Literal[2]
-reveal_type(len((*[], 1, 2)))  # revealed: Literal[3]
-
-# TODO: Handle star unpacks; Should be: Literal[0]
-reveal_type(len((*[], *{})))  # revealed: Literal[2]
-```
-
-### Lists, sets and dictionaries
-
-```py
-reveal_type(len([]))  # revealed: int
-reveal_type(len([1]))  # revealed: int
-reveal_type(len([1, 2]))  # revealed: int
-reveal_type(len([*{}, *dict()]))  # revealed: int
-
-reveal_type(len({}))  # revealed: int
-reveal_type(len({**{}}))  # revealed: int
-reveal_type(len({**{}, **{}}))  # revealed: int
-
-reveal_type(len({1}))  # revealed: int
-reveal_type(len({1, 2}))  # revealed: int
-reveal_type(len({*[], 2}))  # revealed: int
-
-reveal_type(len(list()))  # revealed: int
-reveal_type(len(set()))  # revealed: int
-reveal_type(len(dict()))  # revealed: int
-reveal_type(len(frozenset()))  # revealed: int
-```
-
-## `__len__`
-
-The returned value of `__len__` is implicitly and recursively converted to `int`.
-
-### Literal integers
-
-```py
-from typing import Literal
-
-class Zero:
-    def __len__(self) -> Literal[0]: ...
-
-class ZeroOrOne:
-    def __len__(self) -> Literal[0, 1]: ...
-
-class ZeroOrTrue:
-    def __len__(self) -> Literal[0, True]: ...
-
-class OneOrFalse:
-    def __len__(self) -> Literal[1] | Literal[False]: ...
-
-class OneOrFoo:
-    def __len__(self) -> Literal[1, "foo"]: ...
-
-class ZeroOrStr:
-    def __len__(self) -> Literal[0] | str: ...
-
-reveal_type(len(Zero()))  # revealed: Literal[0]
-reveal_type(len(ZeroOrOne()))  # revealed: Literal[0, 1]
-reveal_type(len(ZeroOrTrue()))  # revealed: Literal[0, 1]
-reveal_type(len(OneOrFalse()))  # revealed: Literal[0, 1]
-
-# TODO: Emit a diagnostic
-reveal_type(len(OneOrFoo()))  # revealed: int
-
-# TODO: Emit a diagnostic
-reveal_type(len(ZeroOrStr()))  # revealed: int
-```
-
-### Literal booleans
-
-```py
-from typing import Literal
-
-class LiteralTrue:
-    def __len__(self) -> Literal[True]: ...
-
-class LiteralFalse:
-    def __len__(self) -> Literal[False]: ...
-
-reveal_type(len(LiteralTrue()))  # revealed: Literal[1]
-reveal_type(len(LiteralFalse()))  # revealed: Literal[0]
-```
-
-### Enums
-
-```py
-from enum import Enum, auto
-from typing import Literal
-
-class SomeEnum(Enum):
-    AUTO = auto()
-    INT = 2
-    STR = "4"
-    TUPLE = (8, "16")
-    INT_2 = 3_2
-
-class Auto:
-    def __len__(self) -> Literal[SomeEnum.AUTO]: ...
-
-class Int:
-    def __len__(self) -> Literal[SomeEnum.INT]: ...
-
-class Str:
-    def __len__(self) -> Literal[SomeEnum.STR]: ...
-
-class Tuple:
-    def __len__(self) -> Literal[SomeEnum.TUPLE]: ...
-
-class IntUnion:
-    def __len__(self) -> Literal[SomeEnum.INT, SomeEnum.INT_2]: ...
-
-reveal_type(len(Auto()))  # revealed: int
-reveal_type(len(Int()))  # revealed: Literal[2]
-reveal_type(len(Str()))  # revealed: int
-reveal_type(len(Tuple()))  # revealed: int
-reveal_type(len(IntUnion()))  # revealed: Literal[2, 32]
-```
-
-### Negative integers
-
-```py
-from typing import Literal
-
-class Negative:
-    def __len__(self) -> Literal[-1]: ...
-
-# TODO: Emit a diagnostic
-reveal_type(len(Negative()))  # revealed: int
-```
-
-### Wrong signature
-
-```py
-from typing import Literal
-
-class SecondOptionalArgument:
-    def __len__(self, v: int = 0) -> Literal[0]: ...
-
-class SecondRequiredArgument:
-    def __len__(self, v: int) -> Literal[1]: ...
-
-# TODO: Emit a diagnostic
-reveal_type(len(SecondOptionalArgument()))  # revealed: Literal[0]
-
-# TODO: Emit a diagnostic
-reveal_type(len(SecondRequiredArgument()))  # revealed: Literal[1]
-```
-
-### No `__len__`
-
-```py
-class NoDunderLen: ...
-
-# TODO: Emit a diagnostic
-reveal_type(len(NoDunderLen()))  # revealed: int
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/function/parameters.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/function/parameters.md
@@ -1,75 +0,0 @@
-# Function parameter types
-
-Within a function scope, the declared type of each parameter is its annotated type (or Unknown if
-not annotated). The initial inferred type is the union of the declared type with the type of the
-default value expression (if any). If both are fully static types, this union should simplify to the
-annotated type (since the default value type must be assignable to the annotated type, and for fully
-static types this means subtype-of, which simplifies in unions). But if the annotated type is
-Unknown or another non-fully-static type, the default value type may still be relevant as lower
-bound.
-
-The variadic parameter is a variadic tuple of its annotated type; the variadic-keywords parameter is
-a dictionary from strings to its annotated type.
-
-## Parameter kinds
-
-```py
-from typing import Literal
-
-def f(a, b: int, c=1, d: int = 2, /, e=3, f: Literal[4] = 4, *args: object, g=5, h: Literal[6] = 6, **kwargs: str):
-    reveal_type(a)  # revealed: Unknown
-    reveal_type(b)  # revealed: int
-    reveal_type(c)  # revealed: Unknown | Literal[1]
-    reveal_type(d)  # revealed: int
-    reveal_type(e)  # revealed: Unknown | Literal[3]
-    reveal_type(f)  # revealed: Literal[4]
-    reveal_type(g)  # revealed: Unknown | Literal[5]
-    reveal_type(h)  # revealed: Literal[6]
-
-    # TODO: should be `tuple[object, ...]` (needs generics)
-    reveal_type(args)  # revealed: tuple
-
-    # TODO: should be `dict[str, str]` (needs generics)
-    reveal_type(kwargs)  # revealed: dict
-```
-
-## Unannotated variadic parameters
-
-...are inferred as tuple of Unknown or dict from string to Unknown.
-
-```py
-def g(*args, **kwargs):
-    # TODO: should be `tuple[Unknown, ...]` (needs generics)
-    reveal_type(args)  # revealed: tuple
-
-    # TODO: should be `dict[str, Unknown]` (needs generics)
-    reveal_type(kwargs)  # revealed: dict
-```
-
-## Annotation is present but not a fully static type
-
-The default value type should be a lower bound on the inferred type.
-
-```py
-from typing import Any
-
-def f(x: Any = 1):
-    reveal_type(x)  # revealed: Any | Literal[1]
-```
-
-## Default value type must be assignable to annotated type
-
-The default value type must be assignable to the annotated type. If not, we emit a diagnostic, and
-fall back to inferring the annotated type, ignoring the default value type.
-
-```py
-# error: [invalid-parameter-default]
-def f(x: int = "foo"):
-    reveal_type(x)  # revealed: int
-
-# The check is assignable-to, not subtype-of, so this is fine:
-from typing import Any
-
-def g(x: Any = "foo"):
-    reveal_type(x)  # revealed: Any | Literal["foo"]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/generics.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/generics.md
@@ -73,7 +73,7 @@ def f[T]():
 A typevar with less than two constraints emits a diagnostic:

 ```py
-# error: [invalid-type-variable-constraints] "TypeVar must have at least two constrained types"
+# error: [invalid-typevar-constraints] "TypeVar must have at least two constrained types"
 def f[T: (int,)]():
    pass
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/import/conditional.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/import/conditional.md
@@ -3,10 +3,11 @@
 ## Maybe unbound

 ```py path=maybe_unbound.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
+flag = bool_instance()
+if flag:
    y = 3

 x = y  # error: [possibly-unresolved-reference]
@@ -30,12 +31,13 @@ reveal_type(y)  # revealed: Literal[3]
 ## Maybe unbound annotated

 ```py path=maybe_unbound_annotated.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
-    y: int = 3
+flag = bool_instance()

+if flag:
+    y: int = 3
 x = y  # error: [possibly-unresolved-reference]

 # revealed: Literal[3]
@@ -61,10 +63,10 @@ reveal_type(y)  # revealed: int
 Importing a possibly undeclared name still gives us its declared type:

 ```py path=maybe_undeclared.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
+if bool_instance():
    x: int
 ```

@@ -81,12 +83,14 @@ def f(): ...
 ```

 ```py path=b.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
+flag = bool_instance()
+if flag:
    from c import f
 else:
+
    def f(): ...
 ```

@@ -107,10 +111,11 @@ x: int
 ```

 ```py path=b.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
    return True

-if coinflip():
+flag = bool_instance()
+if flag:
    from c import x
 else:
    x = 1
--- a/crates/red_knot_python_semantic/resources/mdtest/import/errors.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/import/errors.md
@@ -55,24 +55,3 @@ from b import x

 x = "foo"  # error: [invalid-assignment] "Object of type `Literal["foo"]"
 ```
-
-## Import cycle
-
-```py path=a.py
-class A: ...
-
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Literal[object]]
-import b
-
-class C(b.B): ...
-
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[B], Literal[A], Literal[object]]
-```
-
-```py path=b.py
-from a import A
-
-class B(A): ...
-
-reveal_type(B.__mro__)  # revealed: tuple[Literal[B], Literal[A], Literal[object]]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/import/invalid_syntax.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/import/invalid_syntax.md
@@ -1,9 +0,0 @@
-# Invalid syntax
-
-## Missing module name
-
-```py
-from import bar  # error: [invalid-syntax]
-
-reveal_type(bar)  # revealed: Unknown
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/invalid_syntax.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/invalid_syntax.md
@@ -1,93 +0,0 @@
-# Syntax errors
-
-Test cases to ensure that red knot does not panic if there are syntax errors in the source code.
-
-The parser cannot recover from certain syntax errors completely which is why the number of syntax
-errors could be more than expected in the following examples. For instance, if there's a keyword
-(like `for`) in the middle of another statement (like function definition), then it's more likely
-that the rest of the tokens are going to be part of the `for` statement and not the function
-definition. But, it's not necessary that the remaining tokens are valid in the context of a `for`
-statement.
-
-## Keyword as identifiers
-
-When keywords are used as identifiers, the parser recovers from this syntax error by emitting an
-error and including the text value of the keyword to create the `Identifier` node.
-
-### Name expression
-
-#### Assignment
-
-```py
-# error: [invalid-syntax]
-pass = 1
-```
-
-#### Type alias
-
-```py
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-type pass = 1
-```
-
-#### Function definition
-
-```py
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-def True(for):
-    # error: [invalid-syntax]
-    # error: [invalid-syntax]
-    pass
-```
-
-#### For
-
-```py
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-# error: [unresolved-reference] "Name `pass` used when not defined"
-for while in pass:
-    pass
-```
-
-#### While
-
-```py
-# error: [invalid-syntax]
-# error: [unresolved-reference] "Name `in` used when not defined"
-while in:
-    pass
-```
-
-#### Match
-
-```py
-# error: [invalid-syntax]
-# error: [invalid-syntax]
-# error: [unresolved-reference] "Name `match` used when not defined"
-match while:
-    # error: [invalid-syntax]
-    # error: [invalid-syntax]
-    # error: [invalid-syntax]
-    # error: [unresolved-reference] "Name `case` used when not defined"
-    case in:
-        # error: [invalid-syntax]
-        # error: [invalid-syntax]
-        pass
-```
-
-### Attribute expression
-
-```py
-# TODO: Check when support for attribute expressions is added
-
-# error: [invalid-syntax]
-# error: [unresolved-reference] "Name `foo` used when not defined"
-for x in foo.pass:
-    pass
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/literal/ellipsis.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/literal/ellipsis.md
@@ -1,7 +0,0 @@
-# Ellipsis literals
-
-## Simple
-
-```py
-reveal_type(...)  # revealed: EllipsisType | ellipsis
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/loops/for.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/loops/for.md
@@ -106,19 +106,23 @@ reveal_type(x)
 ## With non-callable iterator

 ```py
-def _(flag: bool):
-    class NotIterable:
-        if flag:
-            __iter__ = 1
-        else:
-            __iter__ = None
+def bool_instance() -> bool:
+    return True

-    for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
-        pass
+flag = bool_instance()

-    # revealed: Unknown
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)
+class NotIterable:
+    if flag:
+        __iter__ = 1
+    else:
+        __iter__ = None
+
+for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
+    pass
+
+# revealed: Unknown
+# error: [possibly-unresolved-reference]
+reveal_type(x)
 ```

 ## Invalid iterable
@@ -156,9 +160,13 @@ class Test2:
    def __iter__(self) -> TestIter:
        return TestIter()

-def _(flag: bool):
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: int
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+for x in Test() if flag else Test2():
+    reveal_type(x)  # revealed: int
 ```

 ## Union type as iterator
@@ -207,9 +215,13 @@ class Test2:
    def __iter__(self) -> TestIter3 | TestIter4:
        return TestIter3()

-def _(flag: bool):
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: int | Exception | str | tuple[int, int] | bytes | memoryview
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+for x in Test() if flag else Test2():
+    reveal_type(x)  # revealed: int | Exception | str | tuple[int, int] | bytes | memoryview
 ```

 ## Union type as iterable where one union element has no `__iter__` method
@@ -223,10 +235,12 @@ class Test:
    def __iter__(self) -> TestIter:
        return TestIter()

-def _(flag: bool):
-    # error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
-    for x in Test() if flag else 42:
-        reveal_type(x)  # revealed: int
+def coinflip() -> bool:
+    return True
+
+# error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
+for x in Test() if coinflip() else 42:
+    reveal_type(x)  # revealed: int
 ```

 ## Union type as iterable where one union element has invalid `__iter__` method
@@ -244,10 +258,12 @@ class Test2:
    def __iter__(self) -> int:
        return 42

-def _(flag: bool):
-    # error: "Object of type `Test | Test2` is not iterable"
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: Unknown
+def coinflip() -> bool:
+    return True
+
+# error: "Object of type `Test | Test2` is not iterable"
+for x in Test() if coinflip() else Test2():
+    reveal_type(x)  # revealed: Unknown
 ```

 ## Union type as iterator where one union element has no `__next__` method
--- a/crates/red_knot_python_semantic/resources/mdtest/loops/while_loop.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/loops/while_loop.md
@@ -3,45 +3,54 @@
 ## Basic While Loop

 ```py
-def _(flag: bool):
-    x = 1
-    while flag:
-        x = 2
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: Literal[1, 2]
+flag = bool_instance()
+x = 1
+while flag:
+    x = 2
+
+reveal_type(x)  # revealed: Literal[1, 2]
 ```

 ## While with else (no break)

 ```py
-def _(flag: bool):
-    x = 1
-    while flag:
-        x = 2
-    else:
-        reveal_type(x)  # revealed: Literal[1, 2]
-        x = 3
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: Literal[3]
+flag = bool_instance()
+x = 1
+while flag:
+    x = 2
+else:
+    reveal_type(x)  # revealed: Literal[1, 2]
+    x = 3
+
+reveal_type(x)  # revealed: Literal[3]
 ```

 ## While with Else (may break)

 ```py
-def _(flag: bool, flag2: bool):
-    x = 1
-    y = 0
-    while flag:
-        x = 2
-        if flag2:
-            y = 4
-            break
-    else:
-        y = x
-        x = 3
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: Literal[2, 3]
-    reveal_type(y)  # revealed: Literal[1, 2, 4]
+flag, flag2 = bool_instance(), bool_instance()
+x = 1
+y = 0
+while flag:
+    x = 2
+    if flag2:
+        y = 4
+        break
+else:
+    y = x
+    x = 3
+
+reveal_type(x)  # revealed: Literal[2, 3]
+reveal_type(y)  # revealed: Literal[1, 2, 4]
 ```

 ## Nested while loops
--- a/crates/red_knot_python_semantic/resources/mdtest/mdtest_config.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/mdtest_config.md
@@ -1,67 +0,0 @@
-This test makes sure that `red_knot_test` correctly parses the TOML configuration blocks and applies
-the correct settings hierarchically.
-
-The following configuration will be attached to the *root* section (without any heading):
-
-```toml
-[environment]
-target-version = "3.10"
-```
-
-# Basic
-
-Here, we simply make sure that we pick up the global configuration from the root section:
-
-```py
-reveal_type(sys.version_info[:2] == (3, 10))  # revealed: Literal[True]
-```
-
-# Inheritance
-
-## Child
-
-### Grandchild
-
-The same should work for arbitrarily nested sections:
-
-```py
-reveal_type(sys.version_info[:2] == (3, 10))  # revealed: Literal[True]
-```
-
-# Overwriting
-
-Here, we make sure that we can overwrite the global configuration in a child section:
-
-```toml
-[environment]
-target-version = "3.11"
-```
-
-```py
-reveal_type(sys.version_info[:2] == (3, 11))  # revealed: Literal[True]
-```
-
-# No global state
-
-There is no global state. This section should again use the root configuration:
-
-```py
-reveal_type(sys.version_info[:2] == (3, 10))  # revealed: Literal[True]
-```
-
-# Overwriting affects children
-
-Children in this section should all use the section configuration:
-
-```toml
-[environment]
-target-version = "3.12"
-```
-
-## Child
-
-### Grandchild
-
-```py
-reveal_type(sys.version_info[:2] == (3, 12))  # revealed: Literal[True]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/metaclass.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/metaclass.md
@@ -179,9 +179,9 @@ reveal_type(A.__class__)  # revealed: @Todo(metaclass not a class)
 Retrieving the metaclass of a cyclically defined class should not cause an infinite loop.

 ```py path=a.pyi
-class A(B): ...  # error: [cyclic-class-definition]
-class B(C): ...  # error: [cyclic-class-definition]
-class C(A): ...  # error: [cyclic-class-definition]
+class A(B): ...  # error: [cyclic-class-def]
+class B(C): ...  # error: [cyclic-class-def]
+class C(A): ...  # error: [cyclic-class-def]

 reveal_type(A.__class__)  # revealed: Unknown
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/mro.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/mro.md
@@ -348,14 +348,14 @@ reveal_type(unknown_object.__mro__)  # revealed: Unknown
 These are invalid, but we need to be able to handle them gracefully without panicking.

 ```py path=a.pyi
-class Foo(Foo): ...  # error: [cyclic-class-definition]
+class Foo(Foo): ...  # error: [cyclic-class-def]

 reveal_type(Foo)  # revealed: Literal[Foo]
 reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]

 class Bar: ...
 class Baz: ...
-class Boz(Bar, Baz, Boz): ...  # error: [cyclic-class-definition]
+class Boz(Bar, Baz, Boz): ...  # error: [cyclic-class-def]

 reveal_type(Boz)  # revealed: Literal[Boz]
 reveal_type(Boz.__mro__)  # revealed: tuple[Literal[Boz], Unknown, Literal[object]]
@@ -366,9 +366,9 @@ reveal_type(Boz.__mro__)  # revealed: tuple[Literal[Boz], Unknown, Literal[objec
 These are similarly unlikely, but we still shouldn't crash:

 ```py path=a.pyi
-class Foo(Bar): ...  # error: [cyclic-class-definition]
-class Bar(Baz): ...  # error: [cyclic-class-definition]
-class Baz(Foo): ...  # error: [cyclic-class-definition]
+class Foo(Bar): ...  # error: [cyclic-class-def]
+class Bar(Baz): ...  # error: [cyclic-class-def]
+class Baz(Foo): ...  # error: [cyclic-class-def]

 reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
 reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
@@ -379,9 +379,9 @@ reveal_type(Baz.__mro__)  # revealed: tuple[Literal[Baz], Unknown, Literal[objec

 ```py path=a.pyi
 class Spam: ...
-class Foo(Bar): ...  # error: [cyclic-class-definition]
-class Bar(Baz): ...  # error: [cyclic-class-definition]
-class Baz(Foo, Spam): ...  # error: [cyclic-class-definition]
+class Foo(Bar): ...  # error: [cyclic-class-def]
+class Bar(Baz): ...  # error: [cyclic-class-def]
+class Baz(Foo, Spam): ...  # error: [cyclic-class-def]

 reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
 reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
@@ -391,16 +391,16 @@ reveal_type(Baz.__mro__)  # revealed: tuple[Literal[Baz], Unknown, Literal[objec
 ## Classes with cycles in their MRO, and a sub-graph

 ```py path=a.pyi
-class FooCycle(BarCycle): ...  # error: [cyclic-class-definition]
+class FooCycle(BarCycle): ...  # error: [cyclic-class-def]
 class Foo: ...
-class BarCycle(FooCycle): ...  # error: [cyclic-class-definition]
+class BarCycle(FooCycle): ...  # error: [cyclic-class-def]
 class Bar(Foo): ...

 # TODO: can we avoid emitting the errors for these?
 # The classes have cyclic superclasses,
 # but are not themselves cyclic...
-class Baz(Bar, BarCycle): ...  # error: [cyclic-class-definition]
-class Spam(Baz): ...  # error: [cyclic-class-definition]
+class Baz(Bar, BarCycle): ...  # error: [cyclic-class-def]
+class Spam(Baz): ...  # error: [cyclic-class-def]

 reveal_type(FooCycle.__mro__)  # revealed: tuple[Literal[FooCycle], Unknown, Literal[object]]
 reveal_type(BarCycle.__mro__)  # revealed: tuple[Literal[BarCycle], Unknown, Literal[object]]
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/bool-call.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/bool-call.md
@@ -1,32 +1,32 @@
 ## Narrowing for `bool(..)` checks

 ```py
-def _(flag: bool):
+def flag() -> bool: ...

-    x = 1 if flag else None
+x = 1 if flag() else None

-    # valid invocation, positive
+# valid invocation, positive
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None):
+    reveal_type(x)  # revealed: Literal[1]
+
+# valid invocation, negative
+reveal_type(x)  # revealed: Literal[1] | None
+if not bool(x is not None):
+    reveal_type(x)  # revealed: None
+
+# no args/narrowing
+reveal_type(x)  # revealed: Literal[1] | None
+if not bool():
    reveal_type(x)  # revealed: Literal[1] | None
-    if bool(x is not None):
-        reveal_type(x)  # revealed: Literal[1]

-    # valid invocation, negative
+# invalid invocation, too many positional args
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None, 5):  # TODO diagnostic
    reveal_type(x)  # revealed: Literal[1] | None
-    if not bool(x is not None):
-        reveal_type(x)  # revealed: None

-    # no args/narrowing
+# invalid invocation, too many kwargs
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None, y=5):  # TODO diagnostic
    reveal_type(x)  # revealed: Literal[1] | None
-    if not bool():
-        reveal_type(x)  # revealed: Literal[1] | None
-
-    # invalid invocation, too many positional args
-    reveal_type(x)  # revealed: Literal[1] | None
-    if bool(x is not None, 5):  # TODO diagnostic
-        reveal_type(x)  # revealed: Literal[1] | None
-
-    # invalid invocation, too many kwargs
-    reveal_type(x)  # revealed: Literal[1] | None
-    if bool(x is not None, y=5):  # TODO diagnostic
-        reveal_type(x)  # revealed: Literal[1] | None
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/boolean.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/boolean.md
@@ -9,67 +9,85 @@ Similarly, in `and` expressions, the right-hand side is evaluated only if the le
 ## Narrowing in `or`

 ```py
-def _(flag: bool):
-    class A: ...
-    x: A | None = A() if flag else None
+def bool_instance() -> bool:
+    return True

-    isinstance(x, A) or reveal_type(x)  # revealed: None
-    x is None or reveal_type(x)  # revealed: A
-    reveal_type(x)  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+isinstance(x, A) or reveal_type(x)  # revealed: None
+x is None or reveal_type(x)  # revealed: A
+reveal_type(x)  # revealed: A | None
 ```

 ## Narrowing in `and`

 ```py
-def _(flag: bool):
-    class A: ...
-    x: A | None = A() if flag else None
+def bool_instance() -> bool:
+    return True

-    isinstance(x, A) and reveal_type(x)  # revealed: A
-    x is None and reveal_type(x)  # revealed: None
-    reveal_type(x)  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+isinstance(x, A) and reveal_type(x)  # revealed: A
+x is None and reveal_type(x)  # revealed: None
+reveal_type(x)  # revealed: A | None
 ```

 ## Multiple `and` arms

 ```py
-def _(flag1: bool, flag2: bool, flag3: bool, flag4: bool):
-    class A: ...
-    x: A | None = A() if flag1 else None
+def bool_instance() -> bool:
+    return True

-    flag2 and isinstance(x, A) and reveal_type(x)  # revealed: A
-    isinstance(x, A) and flag2 and reveal_type(x)  # revealed: A
-    reveal_type(x) and isinstance(x, A) and flag3  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+bool_instance() and isinstance(x, A) and reveal_type(x)  # revealed: A
+isinstance(x, A) and bool_instance() and reveal_type(x)  # revealed: A
+reveal_type(x) and isinstance(x, A) and bool_instance()  # revealed: A | None
 ```

 ## Multiple `or` arms

 ```py
-def _(flag1: bool, flag2: bool, flag3: bool, flag4: bool):
-    class A: ...
-    x: A | None = A() if flag1 else None
+def bool_instance() -> bool:
+    return True

-    flag2 or isinstance(x, A) or reveal_type(x)  # revealed: None
-    isinstance(x, A) or flag3 or reveal_type(x)  # revealed: None
-    reveal_type(x) or isinstance(x, A) or flag4  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+bool_instance() or isinstance(x, A) or reveal_type(x)  # revealed: None
+isinstance(x, A) or bool_instance() or reveal_type(x)  # revealed: None
+reveal_type(x) or isinstance(x, A) or bool_instance()  # revealed: A | None
 ```

 ## Multiple predicates

 ```py
-def _(flag1: bool, flag2: bool):
-    class A: ...
-    x: A | None | Literal[1] = A() if flag1 else None if flag2 else 1
+def bool_instance() -> bool:
+    return True

-    x is None or isinstance(x, A) or reveal_type(x)  # revealed: Literal[1]
+class A: ...
+
+x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
+
+x is None or isinstance(x, A) or reveal_type(x)  # revealed: Literal[1]
 ```

 ## Mix of `and` and `or`

 ```py
-def _(flag1: bool, flag2: bool):
-    class A: ...
-    x: A | None | Literal[1] = A() if flag1 else None if flag2 else 1
+def bool_instance() -> bool:
+    return True

-    isinstance(x, A) or x is not None and reveal_type(x)  # revealed: Literal[1]
+class A: ...
+
+x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
+
+isinstance(x, A) or x is not None and reveal_type(x)  # revealed: Literal[1]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/boolean.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/boolean.md
@@ -6,11 +6,15 @@
 class A: ...
 class B: ...

-def _(x: A | B):
-    if isinstance(x, A) and isinstance(x, B):
-        reveal_type(x)  # revealed:  A & B
-    else:
-        reveal_type(x)  # revealed:  B & ~A | A & ~B
+def instance() -> A | B:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) and isinstance(x, B):
+    reveal_type(x)  # revealed:  A & B
+else:
+    reveal_type(x)  # revealed:  B & ~A | A & ~B
 ```

 ## Arms might not add narrowing constraints
@@ -19,18 +23,25 @@ def _(x: A | B):
 class A: ...
 class B: ...

-def _(flag: bool, x: A | B):
-    if isinstance(x, A) and flag:
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+def bool_instance() -> bool:
+    return True

-    if flag and isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+def instance() -> A | B:
+    return A()

+x = instance()
+
+if isinstance(x, A) and bool_instance():
+    reveal_type(x)  # revealed: A
+else:
    reveal_type(x)  # revealed: A | B
+
+if bool_instance() and isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: A | B
+
+reveal_type(x)  # revealed: A | B
 ```

 ## Statically known arms
@@ -39,35 +50,39 @@ def _(flag: bool, x: A | B):
 class A: ...
 class B: ...

-def _(x: A | B):
-    if isinstance(x, A) and True:
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
+def instance() -> A | B:
+    return A()

-    if True and isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
+x = instance()

-    if False and isinstance(x, A):
-        # TODO: should emit an `unreachable code` diagnostic
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+if isinstance(x, A) and True:
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A

-    if False or isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
-
-    if True or isinstance(x, A):
-        reveal_type(x)  # revealed: A | B
-    else:
-        # TODO: should emit an `unreachable code` diagnostic
-        reveal_type(x)  # revealed: B & ~A
+if True and isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A

+if False and isinstance(x, A):
+    # TODO: should emit an `unreachable code` diagnostic
+    reveal_type(x)  # revealed: A
+else:
    reveal_type(x)  # revealed: A | B
+
+if False or isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A
+
+if True or isinstance(x, A):
+    reveal_type(x)  # revealed: A | B
+else:
+    # TODO: should emit an `unreachable code` diagnostic
+    reveal_type(x)  # revealed: B & ~A
+
+reveal_type(x)  # revealed: A | B
 ```

 ## The type of multiple symbols can be narrowed down
@@ -76,17 +91,22 @@ def _(x: A | B):
 class A: ...
 class B: ...

-def _(x: A | B, y: A | B):
-    if isinstance(x, A) and isinstance(y, B):
-        reveal_type(x)  # revealed: A
-        reveal_type(y)  # revealed: B
-    else:
-        # No narrowing: Only-one or both checks might have failed
-        reveal_type(x)  # revealed: A | B
-        reveal_type(y)  # revealed: A | B
+def instance() -> A | B:
+    return A()

+x = instance()
+y = instance()
+
+if isinstance(x, A) and isinstance(y, B):
+    reveal_type(x)  # revealed: A
+    reveal_type(y)  # revealed: B
+else:
+    # No narrowing: Only-one or both checks might have failed
    reveal_type(x)  # revealed: A | B
    reveal_type(y)  # revealed: A | B
+
+reveal_type(x)  # revealed: A | B
+reveal_type(y)  # revealed: A | B
 ```

 ## Narrowing in `or` conditional
@@ -96,11 +116,15 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C):
-    if isinstance(x, A) or isinstance(x, B):
-        reveal_type(x)  # revealed:  A | B
-    else:
-        reveal_type(x)  # revealed:  C & ~A & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) or isinstance(x, B):
+    reveal_type(x)  # revealed:  A | B
+else:
+    reveal_type(x)  # revealed:  C & ~A & ~B
 ```

 ## In `or`, all arms should add constraint in order to narrow
@@ -110,11 +134,18 @@ class A: ...
 class B: ...
 class C: ...

-def _(flag: bool, x: A | B | C):
-    if isinstance(x, A) or isinstance(x, B) or flag:
-        reveal_type(x)  # revealed:  A | B | C
-    else:
-        reveal_type(x)  # revealed:  C & ~A & ~B
+def instance() -> A | B | C:
+    return A()
+
+def bool_instance() -> bool:
+    return True
+
+x = instance()
+
+if isinstance(x, A) or isinstance(x, B) or bool_instance():
+    reveal_type(x)  # revealed:  A | B | C
+else:
+    reveal_type(x)  # revealed:  C & ~A & ~B
 ```

 ## in `or`, all arms should narrow the same set of symbols
@@ -124,23 +155,28 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C, y: A | B | C):
-    if isinstance(x, A) or isinstance(y, A):
-        # The predicate might be satisfied by the right side, so the type of `x` can’t be narrowed down here.
-        reveal_type(x)  # revealed:  A | B | C
-        # The same for `y`
-        reveal_type(y)  # revealed:  A | B | C
-    else:
-        reveal_type(x)  # revealed:  B & ~A | C & ~A
-        reveal_type(y)  # revealed:  B & ~A | C & ~A
+def instance() -> A | B | C:
+    return A()

-    if (isinstance(x, A) and isinstance(y, A)) or (isinstance(x, B) and isinstance(y, B)):
-        # Here, types of `x` and `y` can be narrowd since all `or` arms constraint them.
-        reveal_type(x)  # revealed:  A | B
-        reveal_type(y)  # revealed:  A | B
-    else:
-        reveal_type(x)  # revealed:  A | B | C
-        reveal_type(y)  # revealed:  A | B | C
+x = instance()
+y = instance()
+
+if isinstance(x, A) or isinstance(y, A):
+    # The predicate might be satisfied by the right side, so the type of `x` can’t be narrowed down here.
+    reveal_type(x)  # revealed:  A | B | C
+    # The same for `y`
+    reveal_type(y)  # revealed:  A | B | C
+else:
+    reveal_type(x)  # revealed:  B & ~A | C & ~A
+    reveal_type(y)  # revealed:  B & ~A | C & ~A
+
+if (isinstance(x, A) and isinstance(y, A)) or (isinstance(x, B) and isinstance(y, B)):
+    # Here, types of `x` and `y` can be narrowd since all `or` arms constraint them.
+    reveal_type(x)  # revealed:  A | B
+    reveal_type(y)  # revealed:  A | B
+else:
+    reveal_type(x)  # revealed:  A | B | C
+    reveal_type(y)  # revealed:  A | B | C
 ```

 ## mixing `and` and `not`
@@ -150,12 +186,16 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C):
-    if isinstance(x, B) and not isinstance(x, C):
-        reveal_type(x)  # revealed:  B & ~C
-    else:
-        # ~(B & ~C) -> ~B | C -> (A & ~B) | (C & ~B) | C -> (A & ~B) | C
-        reveal_type(x)  # revealed: A & ~B | C
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, B) and not isinstance(x, C):
+    reveal_type(x)  # revealed:  B & ~C
+else:
+    # ~(B & ~C) -> ~B | C -> (A & ~B) | (C & ~B) | C -> (A & ~B) | C
+    reveal_type(x)  # revealed: A & ~B | C
 ```

 ## mixing `or` and `not`
@@ -165,11 +205,15 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C):
-    if isinstance(x, B) or not isinstance(x, C):
-        reveal_type(x)  # revealed: B | A & ~C
-    else:
-        reveal_type(x)  # revealed: C & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, B) or not isinstance(x, C):
+    reveal_type(x)  # revealed: B | A & ~C
+else:
+    reveal_type(x)  # revealed: C & ~B
 ```

 ## `or` with nested `and`
@@ -179,12 +223,16 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C):
-    if isinstance(x, A) or (isinstance(x, B) and not isinstance(x, C)):
-        reveal_type(x)  # revealed:  A | B & ~C
-    else:
-        # ~(A | (B & ~C)) -> ~A & ~(B & ~C) -> ~A & (~B | C) -> (~A & C) | (~A ~ B)
-        reveal_type(x)  # revealed:  C & ~A
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) or (isinstance(x, B) and not isinstance(x, C)):
+    reveal_type(x)  # revealed:  A | B & ~C
+else:
+    # ~(A | (B & ~C)) -> ~A & ~(B & ~C) -> ~A & (~B | C) -> (~A & C) | (~A ~ B)
+    reveal_type(x)  # revealed:  C & ~A
 ```

 ## `and` with nested `or`
@@ -194,32 +242,41 @@ class A: ...
 class B: ...
 class C: ...

-def _(x: A | B | C):
-    if isinstance(x, A) and (isinstance(x, B) or not isinstance(x, C)):
-        # A & (B | ~C) -> (A & B) | (A & ~C)
-        reveal_type(x)  # revealed:  A & B | A & ~C
-    else:
-        # ~((A & B) | (A & ~C)) ->
-        # ~(A & B) & ~(A & ~C) ->
-        # (~A | ~B) & (~A | C) ->
-        # [(~A | ~B) & ~A] | [(~A | ~B) & C] ->
-        # ~A | (~A & C) | (~B & C) ->
-        # ~A | (C & ~B) ->
-        # ~A | (C & ~B)  The positive side of ~A is  A | B | C ->
-        reveal_type(x)  # revealed:  B & ~A | C & ~A | C & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) and (isinstance(x, B) or not isinstance(x, C)):
+    # A & (B | ~C) -> (A & B) | (A & ~C)
+    reveal_type(x)  # revealed:  A & B | A & ~C
+else:
+    # ~((A & B) | (A & ~C)) ->
+    # ~(A & B) & ~(A & ~C) ->
+    # (~A | ~B) & (~A | C) ->
+    # [(~A | ~B) & ~A] | [(~A | ~B) & C] ->
+    # ~A | (~A & C) | (~B & C) ->
+    # ~A | (C & ~B) ->
+    # ~A | (C & ~B)  The positive side of ~A is  A | B | C ->
+    reveal_type(x)  # revealed:  B & ~A | C & ~A | C & ~B
 ```

 ## Boolean expression internal narrowing

 ```py
-def _(x: str | None, y: str | None):
-    if x is None and y is not x:
-        reveal_type(y)  # revealed: str
+def optional_string() -> str | None:
+    return None

-    # Neither of the conditions alone is sufficient for narrowing y's type:
-    if x is None:
-        reveal_type(y)  # revealed: str | None
+x = optional_string()
+y = optional_string()

-    if y is not x:
-        reveal_type(y)  # revealed: str | None
+if x is None and y is not x:
+    reveal_type(y)  # revealed: str
+
+# Neither of the conditions alone is sufficient for narrowing y's type:
+if x is None:
+    reveal_type(y)  # revealed: str | None
+
+if y is not x:
+    reveal_type(y)  # revealed: str | None
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/elif_else.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/elif_else.md
@@ -3,47 +3,55 @@
 ## Positive contributions become negative in elif-else blocks

 ```py
-def _(x: int):
-    if x == 1:
-        # cannot narrow; could be a subclass of `int`
-        reveal_type(x)  # revealed: int
-    elif x == 2:
-        reveal_type(x)  # revealed: int & ~Literal[1]
-    elif x != 3:
-        reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
+def int_instance() -> int:
+    return 42
+
+x = int_instance()
+
+if x == 1:
+    # cannot narrow; could be a subclass of `int`
+    reveal_type(x)  # revealed: int
+elif x == 2:
+    reveal_type(x)  # revealed: int & ~Literal[1]
+elif x != 3:
+    reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
 ```

 ## Positive contributions become negative in elif-else blocks, with simplification

 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True

-    if x == 1:
-        # TODO should be Literal[1]
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
-    elif x == 2:
-        # TODO should be Literal[2]
-        reveal_type(x)  # revealed: Literal[2, 3]
-    else:
-        reveal_type(x)  # revealed: Literal[3]
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x == 1:
+    # TODO should be Literal[1]
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
+elif x == 2:
+    # TODO should be Literal[2]
+    reveal_type(x)  # revealed: Literal[2, 3]
+else:
+    reveal_type(x)  # revealed: Literal[3]
 ```

 ## Multiple negative contributions using elif, with simplification

 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True

-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2, 3]
-    elif x != 2:
-        # TODO should be `Literal[1]`
-        reveal_type(x)  # revealed: Literal[1, 3]
-    elif x == 3:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
-    else:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2]
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+elif x != 2:
+    # TODO should be `Literal[1]`
+    reveal_type(x)  # revealed: Literal[1, 3]
+elif x == 3:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
+else:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/is.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/is.md
@@ -3,64 +3,77 @@
 ## `is None`

 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True

-    if x is None:
-        reveal_type(x)  # revealed: None
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+flag = bool_instance()
+x = None if flag else 1

-    reveal_type(x)  # revealed: None | Literal[1]
+if x is None:
+    reveal_type(x)  # revealed: None
+else:
+    reveal_type(x)  # revealed: Literal[1]
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```

 ## `is` for other types

 ```py
-def _(flag: bool):
-    class A: ...
-    x = A()
-    y = x if flag else None
+def bool_instance() -> bool:
+    return True

-    if y is x:
-        reveal_type(y)  # revealed: A
-    else:
-        reveal_type(y)  # revealed: A | None
+flag = bool_instance()

+class A: ...
+
+x = A()
+y = x if flag else None
+
+if y is x:
+    reveal_type(y)  # revealed: A
+else:
    reveal_type(y)  # revealed: A | None
+
+reveal_type(y)  # revealed: A | None
 ```

 ## `is` in chained comparisons

 ```py
-def _(x_flag: bool, y_flag: bool):
-    x = True if x_flag else False
-    y = True if y_flag else False
+def bool_instance() -> bool:
+    return True

+x_flag, y_flag = bool_instance(), bool_instance()
+x = True if x_flag else False
+y = True if y_flag else False
+
+reveal_type(x)  # revealed: bool
+reveal_type(y)  # revealed: bool
+
+if y is x is False:  # Interpreted as `(y is x) and (x is False)`
+    reveal_type(x)  # revealed: Literal[False]
+    reveal_type(y)  # revealed: bool
+else:
+    # The negation of the clause above is (y is not x) or (x is not False)
+    # So we can't narrow the type of x or y here, because each arm of the `or` could be true
    reveal_type(x)  # revealed: bool
    reveal_type(y)  # revealed: bool
-
-    if y is x is False:  # Interpreted as `(y is x) and (x is False)`
-        reveal_type(x)  # revealed: Literal[False]
-        reveal_type(y)  # revealed: bool
-    else:
-        # The negation of the clause above is (y is not x) or (x is not False)
-        # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-        reveal_type(x)  # revealed: bool
-        reveal_type(y)  # revealed: bool
 ```

 ## `is` in elif clause

 ```py
-def _(flag1: bool, flag2: bool):
-    x = None if flag1 else (1 if flag2 else True)
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: None | Literal[1] | Literal[True]
-    if x is None:
-        reveal_type(x)  # revealed: None
-    elif x is True:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+x = None if bool_instance() else (1 if bool_instance() else True)
+
+reveal_type(x)  # revealed: None | Literal[1] | Literal[True]
+if x is None:
+    reveal_type(x)  # revealed: None
+elif x is True:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    reveal_type(x)  # revealed: Literal[1]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/is_not.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/is_not.md
@@ -5,28 +5,34 @@
 The type guard removes `None` from the union type:

 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True

-    if x is not None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: None
+flag = bool_instance()
+x = None if flag else 1

-    reveal_type(x)  # revealed: None | Literal[1]
+if x is not None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: None
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```

 ## `is not` for other singleton types

 ```py
-def _(flag: bool):
-    x = True if flag else False
-    reveal_type(x)  # revealed: bool
+def bool_instance() -> bool:
+    return True

-    if x is not False:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        reveal_type(x)  # revealed: Literal[False]
+flag = bool_instance()
+x = True if flag else False
+reveal_type(x)  # revealed: bool
+
+if x is not False:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    reveal_type(x)  # revealed: Literal[False]
 ```

 ## `is not` for non-singleton types
@@ -47,17 +53,20 @@ else:
 ## `is not` for other types

 ```py
-def _(flag: bool):
-    class A: ...
-    x = A()
-    y = x if flag else None
+def bool_instance() -> bool:
+    return True

-    if y is not x:
-        reveal_type(y)  # revealed: A | None
-    else:
-        reveal_type(y)  # revealed: A
+class A: ...

+x = A()
+y = x if bool_instance() else None
+
+if y is not x:
    reveal_type(y)  # revealed: A | None
+else:
+    reveal_type(y)  # revealed: A
+
+reveal_type(y)  # revealed: A | None
 ```

 ## `is not` in chained comparisons
@@ -65,20 +74,23 @@ def _(flag: bool):
 The type guard removes `False` from the union type of the tested value only.

 ```py
-def _(x_flag: bool, y_flag: bool):
-    x = True if x_flag else False
-    y = True if y_flag else False
+def bool_instance() -> bool:
+    return True
+
+x_flag, y_flag = bool_instance(), bool_instance()
+x = True if x_flag else False
+y = True if y_flag else False
+
+reveal_type(x)  # revealed: bool
+reveal_type(y)  # revealed: bool
+
+if y is not x is not False:  # Interpreted as `(y is not x) and (x is not False)`
+    reveal_type(x)  # revealed: Literal[True]
+    reveal_type(y)  # revealed: bool
+else:
+    # The negation of the clause above is (y is x) or (x is False)
+    # So we can't narrow the type of x or y here, because each arm of the `or` could be true

    reveal_type(x)  # revealed: bool
    reveal_type(y)  # revealed: bool
-
-    if y is not x is not False:  # Interpreted as `(y is not x) and (x is not False)`
-        reveal_type(x)  # revealed: Literal[True]
-        reveal_type(y)  # revealed: bool
-    else:
-        # The negation of the clause above is (y is x) or (x is False)
-        # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-
-        reveal_type(x)  # revealed: bool
-        reveal_type(y)  # revealed: bool
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/nested.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/nested.md
@@ -3,45 +3,54 @@
 ## Multiple negative contributions

 ```py
-def _(x: int):
-    if x != 1:
-        if x != 2:
-            if x != 3:
-                reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
+def int_instance() -> int:
+    return 42
+
+x = int_instance()
+
+if x != 1:
+    if x != 2:
+        if x != 3:
+            reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
 ```

 ## Multiple negative contributions with simplification

 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True

-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2, 3]
-        if x != 2:
-            reveal_type(x)  # revealed: Literal[3]
+flag1, flag2 = bool_instance(), bool_instance()
+x = 1 if flag1 else 2 if flag2 else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+    if x != 2:
+        reveal_type(x)  # revealed: Literal[3]
 ```

 ## elif-else blocks

 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True

-    if x != 1:
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+    if x == 2:
+        # TODO should be `Literal[2]`
        reveal_type(x)  # revealed: Literal[2, 3]
-        if x == 2:
-            # TODO should be `Literal[2]`
-            reveal_type(x)  # revealed: Literal[2, 3]
-        elif x == 3:
-            reveal_type(x)  # revealed: Literal[3]
-        else:
-            reveal_type(x)  # revealed: Never
-
-    elif x != 2:
-        # TODO should be Literal[1]
-        reveal_type(x)  # revealed: Literal[1, 3]
+    elif x == 3:
+        reveal_type(x)  # revealed: Literal[3]
    else:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
+        reveal_type(x)  # revealed: Never
+
+elif x != 2:
+    # TODO should be Literal[1]
+    reveal_type(x)  # revealed: Literal[1, 3]
+else:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/not.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/not.md
@@ -5,25 +5,29 @@ The `not` operator negates a constraint.
 ## `not is None`

 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True

-    if not x is None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: None
+x = None if bool_instance() else 1

-    reveal_type(x)  # revealed: None | Literal[1]
+if not x is None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: None
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```

 ## `not isinstance`

 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    if not isinstance(x, (int)):
-        reveal_type(x)  # revealed: Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+x = 1 if bool_instance() else "a"
+
+if not isinstance(x, (int)):
+    reveal_type(x)  # revealed: Literal["a"]
+else:
+    reveal_type(x)  # revealed: Literal[1]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/not_eq.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/not_eq.md
@@ -3,66 +3,82 @@
 ## `x != None`

 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True

-    if x != None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        # TODO should be None
-        reveal_type(x)  # revealed: None | Literal[1]
+flag = bool_instance()
+x = None if flag else 1
+
+if x != None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    # TODO should be None
+    reveal_type(x)  # revealed: None | Literal[1]
 ```

 ## `!=` for other singleton types

 ```py
-def _(flag: bool):
-    x = True if flag else False
+def bool_instance() -> bool:
+    return True

-    if x != False:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        # TODO should be Literal[False]
-        reveal_type(x)  # revealed: bool
+flag = bool_instance()
+x = True if flag else False
+
+if x != False:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    # TODO should be Literal[False]
+    reveal_type(x)  # revealed: bool
 ```

 ## `x != y` where `y` is of literal type

 ```py
-def _(flag: bool):
-    x = 1 if flag else 2
+def bool_instance() -> bool:
+    return True

-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2]
+flag = bool_instance()
+x = 1 if flag else 2
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2]
 ```

 ## `x != y` where `y` is a single-valued type

 ```py
-def _(flag: bool):
-    class A: ...
-    class B: ...
-    C = A if flag else B
+def bool_instance() -> bool:
+    return True

-    if C != A:
-        reveal_type(C)  # revealed: Literal[B]
-    else:
-        # TODO should be Literal[A]
-        reveal_type(C)  # revealed: Literal[A, B]
+flag = bool_instance()
+
+class A: ...
+class B: ...
+
+C = A if flag else B
+
+if C != A:
+    reveal_type(C)  # revealed: Literal[B]
+else:
+    # TODO should be Literal[A]
+    reveal_type(C)  # revealed: Literal[A, B]
 ```

 ## `x != y` where `y` has multiple single-valued options

 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2
-    y = 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True

-    if x != y:
-        reveal_type(x)  # revealed: Literal[1, 2]
-    else:
-        # TODO should be Literal[2]
-        reveal_type(x)  # revealed: Literal[1, 2]
+x = 1 if bool_instance() else 2
+y = 2 if bool_instance() else 3
+
+if x != y:
+    reveal_type(x)  # revealed: Literal[1, 2]
+else:
+    # TODO should be Literal[2]
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```

 ## `!=` for non-single-valued types
@@ -70,22 +86,34 @@ def _(flag1: bool, flag2: bool):
 Only single-valued types should narrow the type:

 ```py
-def _(flag: bool, a: int, y: int):
-    x = a if flag else None
+def bool_instance() -> bool:
+    return True

-    if x != y:
-        reveal_type(x)  # revealed: int | None
+def int_instance() -> int:
+    return 42
+
+flag = bool_instance()
+x = int_instance() if flag else None
+y = int_instance()
+
+if x != y:
+    reveal_type(x)  # revealed: int | None
 ```

 ## Mix of single-valued and non-single-valued types

 ```py
-def _(flag1: bool, flag2: bool, a: int):
-    x = 1 if flag1 else 2
-    y = 2 if flag2 else a
+def int_instance() -> int:
+    return 42

-    if x != y:
-        reveal_type(x)  # revealed: Literal[1, 2]
-    else:
-        reveal_type(x)  # revealed: Literal[1, 2]
+def bool_instance() -> bool:
+    return True
+
+x = 1 if bool_instance() else 2
+y = 2 if bool_instance() else int_instance()
+
+if x != y:
+    reveal_type(x)  # revealed: Literal[1, 2]
+else:
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/isinstance.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/isinstance.md
@@ -5,19 +5,23 @@ Narrowing for `isinstance(object, classinfo)` expressions.
 ## `classinfo` is a single type

 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

+flag = bool_instance()
+
+x = 1 if flag else "a"
+
+if isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1]
+
+if isinstance(x, str):
+    reveal_type(x)  # revealed: Literal["a"]
    if isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+        reveal_type(x)  # revealed: Never

-    if isinstance(x, str):
-        reveal_type(x)  # revealed: Literal["a"]
-        if isinstance(x, int):
-            reveal_type(x)  # revealed: Never
-
-    if isinstance(x, (int, object)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+if isinstance(x, (int, object)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```

 ## `classinfo` is a tuple of types
@@ -26,48 +30,56 @@ Note: `isinstance(x, (int, str))` should not be confused with `isinstance(x, tup
 The former is equivalent to `isinstance(x, int | str)`:

 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    if isinstance(x, (int, str)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Never
+flag, flag1, flag2 = bool_instance(), bool_instance(), bool_instance()

-    if isinstance(x, (int, bytes)):
-        reveal_type(x)  # revealed: Literal[1]
+x = 1 if flag else "a"

-    if isinstance(x, (bytes, str)):
-        reveal_type(x)  # revealed: Literal["a"]
+if isinstance(x, (int, str)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+else:
+    reveal_type(x)  # revealed: Never

-    # No narrowing should occur if a larger type is also
-    # one of the possibilities:
-    if isinstance(x, (int, object)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Never
+if isinstance(x, (int, bytes)):
+    reveal_type(x)  # revealed: Literal[1]

-    y = 1 if flag1 else "a" if flag2 else b"b"
-    if isinstance(y, (int, str)):
-        reveal_type(y)  # revealed: Literal[1] | Literal["a"]
+if isinstance(x, (bytes, str)):
+    reveal_type(x)  # revealed: Literal["a"]

-    if isinstance(y, (int, bytes)):
-        reveal_type(y)  # revealed: Literal[1] | Literal[b"b"]
+# No narrowing should occur if a larger type is also
+# one of the possibilities:
+if isinstance(x, (int, object)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+else:
+    reveal_type(x)  # revealed: Never

-    if isinstance(y, (str, bytes)):
-        reveal_type(y)  # revealed: Literal["a"] | Literal[b"b"]
+y = 1 if flag1 else "a" if flag2 else b"b"
+if isinstance(y, (int, str)):
+    reveal_type(y)  # revealed: Literal[1] | Literal["a"]
+
+if isinstance(y, (int, bytes)):
+    reveal_type(y)  # revealed: Literal[1] | Literal[b"b"]
+
+if isinstance(y, (str, bytes)):
+    reveal_type(y)  # revealed: Literal["a"] | Literal[b"b"]
 ```

 ## `classinfo` is a nested tuple of types

 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    if isinstance(x, (bool, (bytes, int))):
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: Literal["a"]
+flag = bool_instance()
+
+x = 1 if flag else "a"
+
+if isinstance(x, (bool, (bytes, int))):
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: Literal["a"]
 ```

 ## Class types
@@ -77,7 +89,9 @@ class A: ...
 class B: ...
 class C: ...

-x = object()
+def get_object() -> object: ...
+
+x = get_object()

 if isinstance(x, A):
    reveal_type(x)  # revealed: A
@@ -98,40 +112,50 @@ else:
 ## No narrowing for instances of `builtins.type`

 ```py
-def _(flag: bool):
-    t = type("t", (), {})
+def bool_instance() -> bool:
+    return True

-    # This isn't testing what we want it to test if we infer anything more precise here:
-    reveal_type(t)  # revealed: type
+flag = bool_instance()

-    x = 1 if flag else "foo"
+t = type("t", (), {})

-    if isinstance(x, t):
-        reveal_type(x)  # revealed: Literal[1] | Literal["foo"]
+# This isn't testing what we want it to test if we infer anything more precise here:
+reveal_type(t)  # revealed: type
+x = 1 if flag else "foo"
+
+if isinstance(x, t):
+    reveal_type(x)  # revealed: Literal[1] | Literal["foo"]
 ```

 ## Do not use custom `isinstance` for narrowing

 ```py
-def _(flag: bool):
-    def isinstance(x, t):
-        return True
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    if isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+
+def isinstance(x, t):
+    return True
+
+x = 1 if flag else "a"
+if isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```

 ## Do support narrowing if `isinstance` is aliased

 ```py
-def _(flag: bool):
-    isinstance_alias = isinstance
+def bool_instance() -> bool:
+    return True

-    x = 1 if flag else "a"
+flag = bool_instance()

-    if isinstance_alias(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+isinstance_alias = isinstance
+
+x = 1 if flag else "a"
+if isinstance_alias(x, int):
+    reveal_type(x)  # revealed: Literal[1]
 ```

 ## Do support narrowing if `isinstance` is imported
@@ -139,38 +163,46 @@ def _(flag: bool):
 ```py
 from builtins import isinstance as imported_isinstance

-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    if imported_isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+flag = bool_instance()
+x = 1 if flag else "a"
+if imported_isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1]
 ```

 ## Do not narrow if second argument is not a type

 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    # TODO: this should cause us to emit a diagnostic during
-    # type checking
-    if isinstance(x, "a"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+x = 1 if flag else "a"

-    # TODO: this should cause us to emit a diagnostic during
-    # type checking
-    if isinstance(x, "int"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+# TODO: this should cause us to emit a diagnostic during
+# type checking
+if isinstance(x, "a"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+
+# TODO: this should cause us to emit a diagnostic during
+# type checking
+if isinstance(x, "int"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```

 ## Do not narrow if there are keyword arguments

 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True

-    # TODO: this should cause us to emit a diagnostic
-    # (`isinstance` has no `foo` parameter)
-    if isinstance(x, int, foo="bar"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+x = 1 if flag else "a"
+
+# TODO: this should cause us to emit a diagnostic
+# (`isinstance` has no `foo` parameter)
+if isinstance(x, int, foo="bar"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/issubclass.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/issubclass.md
@@ -7,43 +7,45 @@ Narrowing for `issubclass(class, classinfo)` expressions.
 ### Basic example

 ```py
-def _(flag: bool):
-    t = int if flag else str
+def flag() -> bool: ...

-    if issubclass(t, bytes):
-        reveal_type(t)  # revealed: Never
+t = int if flag() else str

-    if issubclass(t, object):
-        reveal_type(t)  # revealed: Literal[int, str]
+if issubclass(t, bytes):
+    reveal_type(t)  # revealed: Never

+if issubclass(t, object):
+    reveal_type(t)  # revealed: Literal[int, str]
+
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+else:
+    reveal_type(t)  # revealed: Literal[str]
+
+if issubclass(t, str):
+    reveal_type(t)  # revealed: Literal[str]
    if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    else:
-        reveal_type(t)  # revealed: Literal[str]
-
-    if issubclass(t, str):
-        reveal_type(t)  # revealed: Literal[str]
-        if issubclass(t, int):
-            reveal_type(t)  # revealed: Never
+        reveal_type(t)  # revealed: Never
 ```

 ### Proper narrowing in `elif` and `else` branches

 ```py
-def _(flag1: bool, flag2: bool):
-    t = int if flag1 else str if flag2 else bytes
+def flag() -> bool: ...

-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    else:
-        reveal_type(t)  # revealed: Literal[str, bytes]
+t = int if flag() else str if flag() else bytes

-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    elif issubclass(t, str):
-        reveal_type(t)  # revealed: Literal[str]
-    else:
-        reveal_type(t)  # revealed: Literal[bytes]
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+else:
+    reveal_type(t)  # revealed: Literal[str, bytes]
+
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+elif issubclass(t, str):
+    reveal_type(t)  # revealed: Literal[str]
+else:
+    reveal_type(t)  # revealed: Literal[bytes]
 ```

 ### Multiple derived classes
@@ -54,28 +56,29 @@ class Derived1(Base): ...
 class Derived2(Base): ...
 class Unrelated: ...

-def _(flag1: bool, flag2: bool, flag3: bool):
-    t1 = Derived1 if flag1 else Derived2
+def flag() -> bool: ...

-    if issubclass(t1, Base):
-        reveal_type(t1)  # revealed: Literal[Derived1, Derived2]
+t1 = Derived1 if flag() else Derived2

-    if issubclass(t1, Derived1):
-        reveal_type(t1)  # revealed: Literal[Derived1]
-    else:
-        reveal_type(t1)  # revealed: Literal[Derived2]
+if issubclass(t1, Base):
+    reveal_type(t1)  # revealed: Literal[Derived1, Derived2]

-    t2 = Derived1 if flag2 else Base
+if issubclass(t1, Derived1):
+    reveal_type(t1)  # revealed: Literal[Derived1]
+else:
+    reveal_type(t1)  # revealed: Literal[Derived2]

-    if issubclass(t2, Base):
-        reveal_type(t2)  # revealed: Literal[Derived1, Base]
+t2 = Derived1 if flag() else Base

-    t3 = Derived1 if flag3 else Unrelated
+if issubclass(t2, Base):
+    reveal_type(t2)  # revealed: Literal[Derived1, Base]

-    if issubclass(t3, Base):
-        reveal_type(t3)  # revealed: Literal[Derived1]
-    else:
-        reveal_type(t3)  # revealed: Literal[Unrelated]
+t3 = Derived1 if flag() else Unrelated
+
+if issubclass(t3, Base):
+    reveal_type(t3)  # revealed: Literal[Derived1]
+else:
+    reveal_type(t3)  # revealed: Literal[Unrelated]
 ```

 ### Narrowing for non-literals
@@ -84,13 +87,16 @@ def _(flag1: bool, flag2: bool, flag3: bool):
 class A: ...
 class B: ...

-def _(t: type[object]):
-    if issubclass(t, A):
-        reveal_type(t)  # revealed: type[A]
-        if issubclass(t, B):
-            reveal_type(t)  # revealed: type[A] & type[B]
-    else:
-        reveal_type(t)  # revealed: type[object] & ~type[A]
+def get_class() -> type[object]: ...
+
+t = get_class()
+
+if issubclass(t, A):
+    reveal_type(t)  # revealed: type[A]
+    if issubclass(t, B):
+        reveal_type(t)  # revealed: type[A] & type[B]
+else:
+    reveal_type(t)  # revealed: type[object] & ~type[A]
 ```

 ### Handling of `None`
@@ -101,15 +107,16 @@ def _(t: type[object]):
 # error: [possibly-unbound-import] "Member `NoneType` of module `types` is possibly unbound"
 from types import NoneType

-def _(flag: bool):
-    t = int if flag else NoneType
+def flag() -> bool: ...

-    if issubclass(t, NoneType):
-        reveal_type(t)  # revealed: Literal[NoneType]
+t = int if flag() else NoneType

-    if issubclass(t, type(None)):
-        # TODO: this should be just `Literal[NoneType]`
-        reveal_type(t)  # revealed: Literal[int, NoneType]
+if issubclass(t, NoneType):
+    reveal_type(t)  # revealed: Literal[NoneType]
+
+if issubclass(t, type(None)):
+    # TODO: this should be just `Literal[NoneType]`
+    reveal_type(t)  # revealed: Literal[int, NoneType]
 ```

 ## `classinfo` contains multiple types
@@ -119,13 +126,14 @@ def _(flag: bool):
 ```py
 class Unrelated: ...

-def _(flag1: bool, flag2: bool):
-    t = int if flag1 else str if flag2 else bytes
+def flag() -> bool: ...

-    if issubclass(t, (int, (Unrelated, (bytes,)))):
-        reveal_type(t)  # revealed: Literal[int, bytes]
-    else:
-        reveal_type(t)  # revealed: Literal[str]
+t = int if flag() else str if flag() else bytes
+
+if issubclass(t, (int, (Unrelated, (bytes,)))):
+    reveal_type(t)  # revealed: Literal[int, bytes]
+else:
+    reveal_type(t)  # revealed: Literal[str]
 ```

 ## Special cases
@@ -140,7 +148,9 @@ to `issubclass`:
 ```py
 class A: ...

-t = object()
+def get_object() -> object: ...
+
+t = get_object()

 # TODO: we should emit a diagnostic here
 if issubclass(t, A):
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/match.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/match.md
@@ -3,16 +3,19 @@
 ## Single `match` pattern

 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True

-    reveal_type(x)  # revealed: None | Literal[1]
+flag = bool_instance()

-    y = 0
+x = None if flag else 1
+reveal_type(x)  # revealed: None | Literal[1]

-    match x:
-        case None:
-            y = x
+y = 0

-    reveal_type(y)  # revealed: Literal[0] | None
+match x:
+    case None:
+        y = x
+
+reveal_type(y)  # revealed: Literal[0] | None
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/post_if_statement.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/post_if_statement.md
@@ -3,49 +3,62 @@
 ## After if-else statements, narrowing has no effect if the variable is not mutated in any branch

 ```py
-def _(x: int | None):
-    if x is None:
-        pass
-    else:
-        pass
+def optional_int() -> int | None: ...

-    reveal_type(x)  # revealed: int | None
+x = optional_int()
+
+if x is None:
+    pass
+else:
+    pass
+
+reveal_type(x)  # revealed: int | None
 ```

 ## Narrowing can have a persistent effect if the variable is mutated in one branch

 ```py
-def _(x: int | None):
-    if x is None:
-        x = 10
-    else:
-        pass
+def optional_int() -> int | None: ...

-    reveal_type(x)  # revealed: int
+x = optional_int()
+
+if x is None:
+    x = 10
+else:
+    pass
+
+reveal_type(x)  # revealed: int
 ```

 ## An if statement without an explicit `else` branch is equivalent to one with a no-op `else` branch

 ```py
-def _(x: int | None, y: int | None):
-    if x is None:
-        x = 0
+def optional_int() -> int | None: ...

-    if y is None:
-        pass
+x = optional_int()
+y = optional_int()

-    reveal_type(x)  # revealed: int
-    reveal_type(y)  # revealed: int | None
+if x is None:
+    x = 0
+
+if y is None:
+    pass
+
+reveal_type(x)  # revealed: int
+reveal_type(y)  # revealed: int | None
 ```

 ## An if-elif without an explicit else branch is equivalent to one with an empty else branch

 ```py
-def _(x: int | None):
-    if x is None:
-        x = 0
-    elif x > 50:
-        x = 50
+def optional_int() -> int | None: ...

-    reveal_type(x)  # revealed: int
+x = optional_int()
+
+if x is None:
+    x = 0
+elif x > 50:
+    x = 50
+
+reveal_type(x)  # revealed: int
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/narrow/type.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/narrow/type.md
@@ -6,14 +6,18 @@
 class A: ...
 class B: ...

-def _(x: A | B):
-    if type(x) is A:
-        reveal_type(x)  # revealed: A
-    else:
-        # It would be wrong to infer `B` here. The type
-        # of `x` could be a subclass of `A`, so we need
-        # to infer the full union type:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is A:
+    reveal_type(x)  # revealed: A
+else:
+    # It would be wrong to infer `B` here. The type
+    # of `x` could be a subclass of `A`, so we need
+    # to infer the full union type:
+    reveal_type(x)  # revealed: A | B
 ```

 ## `type(x) is not C`
@@ -22,12 +26,16 @@ def _(x: A | B):
 class A: ...
 class B: ...

-def _(x: A | B):
-    if type(x) is not A:
-        # Same reasoning as above: no narrowing should occur here.
-        reveal_type(x)  # revealed: A | B
-    else:
-        reveal_type(x)  # revealed: A
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is not A:
+    # Same reasoning as above: no narrowing should occur here.
+    reveal_type(x)  # revealed: A | B
+else:
+    reveal_type(x)  # revealed: A
 ```

 ## `type(x) == C`, `type(x) != C`
@@ -46,12 +54,16 @@ class IsEqualToEverything(type):
 class A(metaclass=IsEqualToEverything): ...
 class B(metaclass=IsEqualToEverything): ...

-def _(x: A | B):
-    if type(x) == A:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return B()

-    if type(x) != A:
-        reveal_type(x)  # revealed: A | B
+x = get_a_or_b()
+
+if type(x) == A:
+    reveal_type(x)  # revealed: A | B
+
+if type(x) != A:
+    reveal_type(x)  # revealed: A | B
 ```

 ## No narrowing for custom `type` callable
@@ -63,11 +75,15 @@ class B: ...
 def type(x):
    return int

-def _(x: A | B):
-    if type(x) is A:
-        reveal_type(x)  # revealed: A | B
-    else:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is A:
+    reveal_type(x)  # revealed: A | B
+else:
+    reveal_type(x)  # revealed: A | B
 ```

 ## No narrowing for multiple arguments
@@ -75,11 +91,15 @@ def _(x: A | B):
 No narrowing should occur if `type` is used to dynamically create a class:

 ```py
-def _(x: str | int):
-    if type(x, (), {}) is str:
-        reveal_type(x)  # revealed: str | int
-    else:
-        reveal_type(x)  # revealed: str | int
+def get_str_or_int() -> str | int:
+    return "test"
+
+x = get_str_or_int()
+
+if type(x, (), {}) is str:
+    reveal_type(x)  # revealed: str | int
+else:
+    reveal_type(x)  # revealed: str | int
 ```

 ## No narrowing for keyword arguments
@@ -87,10 +107,14 @@ def _(x: str | int):
 `type` can't be used with a keyword argument:

 ```py
-def _(x: str | int):
-    # TODO: we could issue a diagnostic here
-    if type(object=x) is str:
-        reveal_type(x)  # revealed: str | int
+def get_str_or_int() -> str | int:
+    return "test"
+
+x = get_str_or_int()
+
+# TODO: we could issue a diagnostic here
+if type(object=x) is str:
+    reveal_type(x)  # revealed: str | int
 ```

 ## Narrowing if `type` is aliased
@@ -101,9 +125,13 @@ class B: ...

 alias_for_type = type

-def _(x: A | B):
-    if alias_for_type(x) is A:
-        reveal_type(x)  # revealed: A
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if alias_for_type(x) is A:
+    reveal_type(x)  # revealed: A
 ```

 ## Limitations
@@ -112,9 +140,13 @@ def _(x: A | B):
 class Base: ...
 class Derived(Base): ...

-def _(x: Base):
-    if type(x) is Base:
-        # Ideally, this could be narrower, but there is now way to
-        # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
-        reveal_type(x)  # revealed: Base
+def get_base() -> Base:
+    return Base()
+
+x = get_base()
+
+if type(x) is Base:
+    # Ideally, this could be narrower, but there is now way to
+    # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
+    reveal_type(x)  # revealed: Base
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/scopes/moduletype_attrs.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/scopes/moduletype_attrs.md
@@ -59,7 +59,7 @@ reveal_type(typing.__init__)  # revealed: Literal[__init__]
 # These come from `builtins.object`, not `types.ModuleType`:
 reveal_type(typing.__eq__)  # revealed: Literal[__eq__]

-reveal_type(typing.__class__)  # revealed: Literal[ModuleType]
+reveal_type(typing.__class__)  # revealed: Literal[type]

 # TODO: needs support for attribute access on instances, properties and generics;
 # should be `dict[str, Any]`
--- a/crates/red_knot_python_semantic/resources/mdtest/scopes/nonlocal.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/scopes/nonlocal.md
@@ -1,45 +0,0 @@
-# Nonlocal references
-
-## One level up
-
-```py
-def f():
-    x = 1
-    def g():
-        reveal_type(x)  # revealed: Literal[1]
-```
-
-## Two levels up
-
-```py
-def f():
-    x = 1
-    def g():
-        def h():
-            reveal_type(x)  # revealed: Literal[1]
-```
-
-## Skips class scope
-
-```py
-def f():
-    x = 1
-
-    class C:
-        x = 2
-        def g():
-            reveal_type(x)  # revealed: Literal[1]
-```
-
-## Skips annotation-only assignment
-
-```py
-def f():
-    x = 1
-    def g():
-        # it's pretty weird to have an annotated assignment in a function where the
-        # name is otherwise not defined; maybe should be an error?
-        x: int
-        def h():
-            reveal_type(x)  # revealed: Literal[1]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/scopes/unbound.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/scopes/unbound.md
@@ -1,57 +0,0 @@
-# Unbound
-
-## Unbound class variable
-
-Name lookups within a class scope fall back to globals, but lookups of class attributes don't.
-
-```py
-def coinflip() -> bool:
-    return True
-
-flag = coinflip()
-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 coinflip() -> bool:
-    return True
-
-if coinflip():
-    x = "abc"
-
-class C:
-    if coinflip():
-        x = 1
-
-    # error: [possibly-unresolved-reference]
-    y = x
-
-reveal_type(C.y)  # revealed: Literal[1] | Literal["abc"]
-```
-
-## Unbound function local
-
-An unbound function local that has definitions in the scope does not fall back to globals.
-
-```py
-x = 1
-
-def f():
-    # error: [unresolved-reference]
-    # revealed: Unknown
-    reveal_type(x)
-    x = 2
-    # revealed: Literal[2]
-    reveal_type(x)
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/shadowing/variable_declaration.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/shadowing/variable_declaration.md
@@ -3,11 +3,14 @@
 ## Shadow after incompatible declarations is OK

 ```py
-def _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True

-    x: bytes = b"foo"
+flag = bool_instance()
+
+if flag:
+    x: str
+else:
+    x: int
+x: bytes = b"foo"
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/stubs/class.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/stubs/class.md
@@ -1,4 +1,4 @@
-# Class definitions in stubs
+# Class defenitions in stubs

 ## Cyclical class definition

--- a/crates/red_knot_python_semantic/resources/mdtest/subscript/bytes.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/subscript/bytes.md
@@ -22,10 +22,12 @@ reveal_type(x)  # revealed: Unknown
 y = b[-6]  # error: [index-out-of-bounds] "Index -6 is out of bounds for bytes literal `Literal[b"\x00abc\xff"]` with length 5"
 reveal_type(y)  # revealed: Unknown

-def _(n: int):
-    a = b"abcde"[n]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(a)  # revealed: @Todo(return type)
+def int_instance() -> int:
+    return 42
+
+a = b"abcde"[int_instance()]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(a)  # revealed: @Todo(return type)
 ```

 ## Slices
@@ -41,13 +43,15 @@ b[:4:0]  # error: [zero-stepsize-in-slice]
 b[0::0]  # error: [zero-stepsize-in-slice]
 b[::0]  # error: [zero-stepsize-in-slice]

-def _(m: int, n: int):
-    byte_slice1 = b[m:n]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(byte_slice1)  # revealed: @Todo(return type)
+def int_instance() -> int: ...

-def _(s: bytes) -> bytes:
-    byte_slice2 = s[0:5]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(byte_slice2)  # revealed: @Todo(return type)
+byte_slice1 = b[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(byte_slice1)  # revealed: @Todo(return type)
+
+def bytes_instance() -> bytes: ...
+
+byte_slice2 = bytes_instance()[0:5]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(byte_slice2)  # revealed: @Todo(return type)
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/subscript/class.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/subscript/class.md
@@ -21,66 +21,77 @@ reveal_type(Identity[0])  # revealed: str
 ## Class getitem union

 ```py
-def _(flag: bool):
-    class UnionClassGetItem:
-        if flag:
-            def __class_getitem__(cls, item: int) -> str:
-                return item
-        else:
-            def __class_getitem__(cls, item: int) -> int:
-                return item
+def bool_instance() -> bool:
+    return True

-    reveal_type(UnionClassGetItem[0])  # revealed: str | int
+class UnionClassGetItem:
+    if bool_instance():
+
+        def __class_getitem__(cls, item: int) -> str:
+            return item
+    else:
+
+        def __class_getitem__(cls, item: int) -> int:
+            return item
+
+reveal_type(UnionClassGetItem[0])  # revealed: str | int
 ```

 ## Class getitem with class union

 ```py
-def _(flag: bool):
-    class A:
-        def __class_getitem__(cls, item: int) -> str:
-            return item
+def bool_instance() -> bool:
+    return True

-    class B:
-        def __class_getitem__(cls, item: int) -> int:
-            return item
+class A:
+    def __class_getitem__(cls, item: int) -> str:
+        return item

-    x = A if flag else B
+class B:
+    def __class_getitem__(cls, item: int) -> int:
+        return item

-    reveal_type(x)  # revealed: Literal[A, B]
-    reveal_type(x[0])  # revealed: str | int
+x = A if bool_instance() else B
+
+reveal_type(x)  # revealed: Literal[A, B]
+reveal_type(x[0])  # revealed: str | int
 ```

 ## Class getitem with unbound method union

 ```py
-def _(flag: bool):
-    if flag:
-        class Spam:
-            def __class_getitem__(self, x: int) -> str:
-                return "foo"
+def bool_instance() -> bool:
+    return True

-    else:
-        class Spam: ...
-    # error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[Spam, Spam]` is possibly unbound"
-    # revealed: str
-    reveal_type(Spam[42])
+if bool_instance():
+    class Spam:
+        def __class_getitem__(self, x: int) -> str:
+            return "foo"
+
+else:
+    class Spam: ...
+
+# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[Spam, Spam]` is possibly unbound"
+# revealed: str
+reveal_type(Spam[42])
 ```

 ## TODO: Class getitem non-class union

 ```py
-def _(flag: bool):
-    if flag:
-        class Eggs:
-            def __class_getitem__(self, x: int) -> str:
-                return "foo"
+def bool_instance() -> bool:
+    return True

-    else:
-        Eggs = 1
+if bool_instance():
+    class Eggs:
+        def __class_getitem__(self, x: int) -> str:
+            return "foo"

-    a = Eggs[42]  # error: "Cannot subscript object of type `Literal[Eggs] | Literal[1]` with no `__getitem__` method"
+else:
+    Eggs = 1

-    # TODO: should _probably_ emit `str | Unknown`
-    reveal_type(a)  # revealed: Unknown
+a = Eggs[42]  # error: "Cannot subscript object of type `Literal[Eggs] | Literal[1]` with no `__getitem__` method"
+
+# TODO: should _probably_ emit `str | Unknown`
+reveal_type(a)  # revealed: Unknown
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/subscript/instance.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/subscript/instance.md
@@ -30,14 +30,18 @@ reveal_type(Identity()[0])  # revealed: int
 ## Getitem union

 ```py
-def _(flag: bool):
-    class Identity:
-        if flag:
-            def __getitem__(self, index: int) -> int:
-                return index
-        else:
-            def __getitem__(self, index: int) -> str:
-                return str(index)
+def bool_instance() -> bool:
+    return True

-    reveal_type(Identity()[0])  # revealed: int | str
+class Identity:
+    if bool_instance():
+
+        def __getitem__(self, index: int) -> int:
+            return index
+    else:
+
+        def __getitem__(self, index: int) -> str:
+            return str(index)
+
+reveal_type(Identity()[0])  # revealed: int | str
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/subscript/string.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/subscript/string.md
@@ -19,10 +19,11 @@ reveal_type(a)  # revealed: Unknown
 b = s[-8]  # error: [index-out-of-bounds] "Index -8 is out of bounds for string `Literal["abcde"]` with length 5"
 reveal_type(b)  # revealed: Unknown

-def _(n: int):
-    a = "abcde"[n]
-    # TODO: Support overloads... Should be `str`
-    reveal_type(a)  # revealed: @Todo(return type)
+def int_instance() -> int: ...
+
+a = "abcde"[int_instance()]
+# TODO: Support overloads... Should be `str`
+reveal_type(a)  # revealed: @Todo(return type)
 ```

 ## Slices
@@ -73,14 +74,17 @@ s[:4:0]  # error: [zero-stepsize-in-slice]
 s[0::0]  # error: [zero-stepsize-in-slice]
 s[::0]  # error: [zero-stepsize-in-slice]

-def _(m: int, n: int, s2: str):
-    substring1 = s[m:n]
-    # TODO: Support overloads... Should be `LiteralString`
-    reveal_type(substring1)  # revealed: @Todo(return type)
+def int_instance() -> int: ...

-    substring2 = s2[0:5]
-    # TODO: Support overloads... Should be `str`
-    reveal_type(substring2)  # revealed: @Todo(return type)
+substring1 = s[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `LiteralString`
+reveal_type(substring1)  # revealed: @Todo(return type)
+
+def str_instance() -> str: ...
+
+substring2 = str_instance()[0:5]
+# TODO: Support overloads... Should be `str`
+reveal_type(substring2)  # revealed: @Todo(return type)
 ```

 ## Unsupported slice types
--- a/crates/red_knot_python_semantic/resources/mdtest/subscript/tuple.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/subscript/tuple.md
@@ -67,60 +67,9 @@ t[:4:0]  # error: [zero-stepsize-in-slice]
 t[0::0]  # error: [zero-stepsize-in-slice]
 t[::0]  # error: [zero-stepsize-in-slice]

-def _(m: int, n: int):
-    tuple_slice = t[m:n]
-    # TODO: Support overloads... Should be `tuple[Literal[1, 'a', b"b"] | None, ...]`
-    reveal_type(tuple_slice)  # revealed: @Todo(return type)
-```
-
-## Inheritance
-
-```toml
-[environment]
-target-version = "3.9"
-```
-
-```py
-# TODO:
-#  * `tuple.__class_getitem__` is always bound on 3.9 (`sys.version_info`)
-#  * `tuple[int, str]` is a valid base (generics)
-# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[tuple]` is possibly unbound"
-# error: [invalid-base] "Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class A(tuple[int, str]): ...
-
-# Runtime value: `(A, tuple, object)`
-# TODO: Generics
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Unknown, Literal[object]]
-```
-
-## `typing.Tuple`
-
-### Correspondence with `tuple`
-
-`typing.Tuple` can be used interchangeably with `tuple`:
-
-```py
-from typing import Tuple
-
-class A: ...
-
-def _(c: Tuple, d: Tuple[int, A], e: Tuple[Any, ...]):
-    reveal_type(c)  # revealed: tuple
-    reveal_type(d)  # revealed: tuple[int, A]
-    reveal_type(e)  # revealed: @Todo(full tuple[...] support)
-```
-
-### Inheritance
-
-Inheriting from `Tuple` results in a MRO with `builtins.tuple` and `typing.Generic`. `Tuple` itself
-is not a class.
-
-```py
-from typing import Tuple
-
-class C(Tuple): ...
-
-# Runtime value: `(C, tuple, typing.Generic, object)`
-# TODO: Add `Generic` to the MRO
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[tuple], Unknown, Literal[object]]
+def int_instance() -> int: ...
+
+tuple_slice = t[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `tuple[Literal[1, 'a', b"b"] | None, ...]`
+reveal_type(tuple_slice)  # revealed: @Todo(return type)
 ```
--- a/crates/red_knot_python_semantic/resources/mdtest/sys_version_info.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/sys_version_info.md
@@ -1,10 +1,5 @@
 # `sys.version_info`

-```toml
-[environment]
-target-version = "3.9"
-```
-
 ## The type of `sys.version_info`

 The type of `sys.version_info` is `sys._version_info`, at least according to typeshed's stubs (which
--- a/crates/red_knot_python_semantic/resources/mdtest/type_of/any.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/type_of/any.md
@@ -1,53 +0,0 @@
-# type[Any]
-
-## Simple
-
-```py
-def f(x: type[Any]):
-    reveal_type(x)  # revealed: type[Any]
-    # TODO: could be `<object.__repr__ type> & Any`
-    reveal_type(x.__repr__)  # revealed: Any
-
-class A: ...
-
-x: type[Any] = object
-x: type[Any] = type
-x: type[Any] = A
-x: type[Any] = A()  # error: [invalid-assignment]
-```
-
-## Bare type
-
-The interpretation of bare `type` is not clear: existing wording in the spec does not match the
-behavior of mypy or pyright. For now we interpret it as simply "an instance of `builtins.type`",
-which is equivalent to `type[object]`. This is similar to the current behavior of mypy, and pyright
-in strict mode.
-
-```py
-def f(x: type):
-    reveal_type(x)  # revealed: type
-    reveal_type(x.__repr__)  # revealed: @Todo(instance attributes)
-
-class A: ...
-
-x: type = object
-x: type = type
-x: type = A
-x: type = A()  # error: [invalid-assignment]
-```
-
-## type[object] != type[Any]
-
-```py
-def f(x: type[object]):
-    reveal_type(x)  # revealed: type[object]
-    # TODO: bound method types
-    reveal_type(x.__repr__)  # revealed: Literal[__repr__]
-
-class A: ...
-
-x: type[object] = object
-x: type[object] = type
-x: type[object] = A
-x: type[object] = A()  # error: [invalid-assignment]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/type_of/basic.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/type_of/basic.md
@@ -1,146 +0,0 @@
-# type special form
-
-## Class literal
-
-```py
-class A: ...
-
-def _(c: type[A]):
-    reveal_type(c)  # revealed: type[A]
-```
-
-## Nested class literal
-
-```py
-class A:
-    class B: ...
-
-def f(c: type[A.B]):
-    reveal_type(c)  # revealed: type[B]
-```
-
-## Deeply nested class literal
-
-```py
-class A:
-    class B:
-        class C: ...
-
-def f(c: type[A.B.C]):
-    reveal_type(c)  # revealed: type[C]
-```
-
-## Class literal from another module
-
-```py
-from a import A
-
-def f(c: type[A]):
-    reveal_type(c)  # revealed: type[A]
-```
-
-```py path=a.py
-class A: ...
-```
-
-## Qualified class literal from another module
-
-```py
-import a
-
-def f(c: type[a.B]):
-    reveal_type(c)  # revealed: type[B]
-```
-
-```py path=a.py
-class B: ...
-```
-
-## Deeply qualified class literal from another module
-
-```py path=a/test.py
-import a.b
-
-# TODO: no diagnostic
-# error: [unresolved-attribute]
-def f(c: type[a.b.C]):
-    reveal_type(c)  # revealed: @Todo(unsupported type[X] special form)
-```
-
-```py path=a/__init__.py
-```
-
-```py path=a/b.py
-class C: ...
-```
-
-## New-style union of classes
-
-```py
-class BasicUser: ...
-class ProUser: ...
-
-class A:
-    class B:
-        class C: ...
-
-def _(u: type[BasicUser | ProUser | A.B.C]):
-    # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(u)
-```
-
-## Old-style union of classes
-
-```py
-from typing import Union
-
-class BasicUser: ...
-class ProUser: ...
-
-class A:
-    class B:
-        class C: ...
-
-def f(a: type[Union[BasicUser, ProUser, A.B.C]], b: type[Union[str]], c: type[Union[BasicUser, Union[ProUser, A.B.C]]]):
-    reveal_type(a)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(b)  # revealed: type[str]
-    reveal_type(c)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-```
-
-## New-style and old-style unions in combination
-
-```py
-from typing import Union
-
-class BasicUser: ...
-class ProUser: ...
-
-class A:
-    class B:
-        class C: ...
-
-def f(a: type[BasicUser | Union[ProUser, A.B.C]], b: type[Union[BasicUser | Union[ProUser, A.B.C | str]]]):
-    reveal_type(a)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(b)  # revealed: type[BasicUser] | type[ProUser] | type[C] | type[str]
-```
-
-## Illegal parameters
-
-```py
-class A: ...
-class B: ...
-
-# error: [invalid-type-form]
-_: type[A, B]
-```
-
-## As a base class
-
-```py
-# TODO: this is a false positive
-# error: [invalid-base] "Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class Foo(type[int]): ...
-
-# TODO: should be `tuple[Literal[Foo], Literal[type], Literal[object]]
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/type_of/typing_dot_Type.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/type_of/typing_dot_Type.md
@@ -1,32 +0,0 @@
-# `typing.Type`
-
-## Annotation
-
-`typing.Type` can be used interchangeably with `type`:
-
-```py
-from typing import Type
-
-class A: ...
-
-def _(c: Type, d: Type[A], e: Type[A]):
-    reveal_type(c)  # revealed: type
-    reveal_type(d)  # revealed: type[A]
-    c = d  # fine
-    d = c  # fine
-```
-
-## Inheritance
-
-Inheriting from `Type` results in a MRO with `builtins.type` and `typing.Generic`. `Type` itself is
-not a class.
-
-```py
-from typing import Type
-
-class C(Type): ...
-
-# Runtime value: `(C, type, typing.Generic, object)`
-# TODO: Add `Generic` to the MRO
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[type], Literal[object]]
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/unary/not.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/unary/not.md
@@ -35,25 +35,29 @@ y = 1
 ## Union

 ```py
-def _(flag: bool):
-    if flag:
-        p = 1
-        q = 3.3
-        r = "hello"
-        s = "world"
-        t = 0
-    else:
-        p = "hello"
-        q = 4
-        r = ""
-        s = 0
-        t = ""
+def bool_instance() -> bool:
+    return True

-    reveal_type(not p)  # revealed: Literal[False]
-    reveal_type(not q)  # revealed: bool
-    reveal_type(not r)  # revealed: bool
-    reveal_type(not s)  # revealed: bool
-    reveal_type(not t)  # revealed: Literal[True]
+flag = bool_instance()
+
+if flag:
+    p = 1
+    q = 3.3
+    r = "hello"
+    s = "world"
+    t = 0
+else:
+    p = "hello"
+    q = 4
+    r = ""
+    s = 0
+    t = ""
+
+reveal_type(not p)  # revealed: Literal[False]
+reveal_type(not q)  # revealed: bool
+reveal_type(not r)  # revealed: bool
+reveal_type(not s)  # revealed: bool
+reveal_type(not t)  # revealed: Literal[True]
 ```

 ## Integer literal
--- a/crates/red_knot_python_semantic/resources/mdtest/unpacking.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/unpacking.md
@@ -267,42 +267,3 @@ reveal_type(b)  # revealed: LiteralString
 # TODO: Should be list[int] once support for assigning to starred expression is added
 reveal_type(c)  # revealed: @Todo(starred unpacking)
 ```
-
-### Unicode
-
-```py
-# TODO: Add diagnostic (need more values to unpack)
-(a, b) = "é"
-
-reveal_type(a)  # revealed: LiteralString
-reveal_type(b)  # revealed: Unknown
-```
-
-### Unicode escape (1)
-
-```py
-# TODO: Add diagnostic (need more values to unpack)
-(a, b) = "\u9E6C"
-
-reveal_type(a)  # revealed: LiteralString
-reveal_type(b)  # revealed: Unknown
-```
-
-### Unicode escape (2)
-
-```py
-# TODO: Add diagnostic (need more values to unpack)
-(a, b) = "\U0010FFFF"
-
-reveal_type(a)  # revealed: LiteralString
-reveal_type(b)  # revealed: Unknown
-```
-
-### Surrogates
-
-```py
-(a, b) = "\uD800\uDFFF"
-
-reveal_type(a)  # revealed: LiteralString
-reveal_type(b)  # revealed: LiteralString
-```
--- a/crates/red_knot_python_semantic/resources/mdtest/with/sync.md
+++ b/crates/red_knot_python_semantic/resources/mdtest/with/sync.md
@@ -21,23 +21,25 @@ with Manager() as f:
 ## Union context manager

 ```py
-def _(flag: bool):
-    class Manager1:
-        def __enter__(self) -> str:
-            return "foo"
+def coinflip() -> bool:
+    return True

-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager1:
+    def __enter__(self) -> str:
+        return "foo"

-    class Manager2:
-        def __enter__(self) -> int:
-            return 42
+    def __exit__(self, exc_type, exc_value, traceback): ...

-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager2:
+    def __enter__(self) -> int:
+        return 42

-    context_expr = Manager1() if flag else Manager2()
+    def __exit__(self, exc_type, exc_value, traceback): ...

-    with context_expr as f:
-        reveal_type(f)  # revealed: str | int
+context_expr = Manager1() if coinflip() else Manager2()
+
+with context_expr as f:
+    reveal_type(f)  # revealed: str | int
 ```

 ## Context manager without an `__enter__` or `__exit__` method
@@ -101,34 +103,39 @@ with Manager():
 ## Context expression with possibly-unbound union variants

 ```py
-def _(flag: bool):
-    class Manager1:
-        def __enter__(self) -> str:
-            return "foo"
+def coinflip() -> bool:
+    return True

-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager1:
+    def __enter__(self) -> str:
+        return "foo"

-    class NotAContextManager: ...
-    context_expr = Manager1() if flag else NotAContextManager()
+    def __exit__(self, exc_type, exc_value, traceback): ...

-    # error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-    # error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__exit__` is possibly unbound"
-    with context_expr as f:
-        reveal_type(f)  # revealed: str
+class NotAContextManager: ...
+
+context_expr = Manager1() if coinflip() else NotAContextManager()
+
+# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__enter__` is possibly unbound"
+# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__exit__` is possibly unbound"
+with context_expr as f:
+    reveal_type(f)  # revealed: str
 ```

 ## Context expression with "sometimes" callable `__enter__` method

 ```py
-def _(flag: bool):
-    class Manager:
-        if flag:
-            def __enter__(self) -> str:
-                return "abcd"
+def coinflip() -> bool:
+    return True

-        def __exit__(self, *args): ...
+class Manager:
+    if coinflip():
+        def __enter__(self) -> str:
+            return "abcd"

-    # error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-    with Manager() as f:
-        reveal_type(f)  # revealed: str
+    def __exit__(self, *args): ...
+
+# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` is possibly unbound"
+with Manager() as f:
+    reveal_type(f)  # revealed: str
 ```
--- a/crates/red_knot_python_semantic/src/db.rs
+++ b/crates/red_knot_python_semantic/src/db.rs
@@ -1,4 +1,3 @@
-use crate::lint::RuleSelection;
 use ruff_db::files::File;
 use ruff_db::{Db as SourceDb, Upcast};

@@ -6,34 +5,26 @@ use ruff_db::{Db as SourceDb, Upcast};
 #[salsa::db]
 pub trait Db: SourceDb + Upcast<dyn SourceDb> {
    fn is_file_open(&self, file: File) -> bool;
-
-    fn rule_selection(&self) -> &RuleSelection;
 }

 #[cfg(test)]
 pub(crate) mod tests {
    use std::sync::Arc;

-    use crate::program::{Program, SearchPathSettings};
-    use crate::python_version::PythonVersion;
-    use crate::{default_lint_registry, ProgramSettings};
-
-    use super::Db;
-    use crate::lint::RuleSelection;
-    use anyhow::Context;
    use ruff_db::files::{File, Files};
-    use ruff_db::system::{DbWithTestSystem, System, SystemPathBuf, TestSystem};
+    use ruff_db::system::{DbWithTestSystem, System, TestSystem};
    use ruff_db::vendored::VendoredFileSystem;
    use ruff_db::{Db as SourceDb, Upcast};

+    use super::Db;
+
    #[salsa::db]
    pub(crate) struct TestDb {
        storage: salsa::Storage<Self>,
        files: Files,
        system: TestSystem,
        vendored: VendoredFileSystem,
-        events: Arc<std::sync::Mutex<Vec<salsa::Event>>>,
-        rule_selection: Arc<RuleSelection>,
+        events: std::sync::Arc<std::sync::Mutex<Vec<salsa::Event>>>,
    }

    impl TestDb {
@@ -42,9 +33,8 @@ pub(crate) mod tests {
                storage: salsa::Storage::default(),
                system: TestSystem::default(),
                vendored: red_knot_vendored::file_system().clone(),
-                events: Arc::default(),
+                events: std::sync::Arc::default(),
                files: Files::default(),
-                rule_selection: Arc::new(RuleSelection::from_registry(&default_lint_registry())),
            }
        }

@@ -107,10 +97,6 @@ pub(crate) mod tests {
        fn is_file_open(&self, file: File) -> bool {
            !file.path(self).is_vendored_path()
        }
-
-        fn rule_selection(&self) -> &RuleSelection {
-            &self.rule_selection
-        }
    }

    #[salsa::db]
@@ -122,66 +108,4 @@ pub(crate) mod tests {
            events.push(event);
        }
    }
-
-    pub(crate) struct TestDbBuilder<'a> {
-        /// Target Python version
-        python_version: PythonVersion,
-        /// Path to a custom typeshed directory
-        custom_typeshed: Option<SystemPathBuf>,
-        /// Path and content pairs for files that should be present
-        files: Vec<(&'a str, &'a str)>,
-    }
-
-    impl<'a> TestDbBuilder<'a> {
-        pub(crate) fn new() -> Self {
-            Self {
-                python_version: PythonVersion::default(),
-                custom_typeshed: None,
-                files: vec![],
-            }
-        }
-
-        pub(crate) fn with_python_version(mut self, version: PythonVersion) -> Self {
-            self.python_version = version;
-            self
-        }
-
-        pub(crate) fn with_custom_typeshed(mut self, path: &str) -> Self {
-            self.custom_typeshed = Some(SystemPathBuf::from(path));
-            self
-        }
-
-        pub(crate) fn with_file(mut self, path: &'a str, content: &'a str) -> Self {
-            self.files.push((path, content));
-            self
-        }
-
-        pub(crate) fn build(self) -> anyhow::Result<TestDb> {
-            let mut db = TestDb::new();
-
-            let src_root = SystemPathBuf::from("/src");
-            db.memory_file_system().create_directory_all(&src_root)?;
-
-            db.write_files(self.files)
-                .context("Failed to write test files")?;
-
-            let mut search_paths = SearchPathSettings::new(src_root);
-            search_paths.custom_typeshed = self.custom_typeshed;
-
-            Program::from_settings(
-                &db,
-                &ProgramSettings {
-                    target_version: self.python_version,
-                    search_paths,
-                },
-            )
-            .context("Failed to configure Program settings")?;
-
-            Ok(db)
-        }
-    }
-
-    pub(crate) fn setup_db() -> TestDb {
-        TestDbBuilder::new().build().expect("valid TestDb setup")
-    }
 }
--- a/crates/red_knot_python_semantic/src/lib.rs
+++ b/crates/red_knot_python_semantic/src/lib.rs
@@ -2,7 +2,6 @@ use std::hash::BuildHasherDefault;

 use rustc_hash::FxHasher;

-use crate::lint::{LintRegistry, LintRegistryBuilder};
 pub use db::Db;
 pub use module_name::ModuleName;
 pub use module_resolver::{resolve_module, system_module_search_paths, Module};
@@ -12,7 +11,6 @@ pub use semantic_model::{HasTy, SemanticModel};

 pub mod ast_node_ref;
 mod db;
-pub mod lint;
 mod module_name;
 mod module_resolver;
 mod node_key;
@@ -28,15 +26,3 @@ mod unpack;
 mod util;

 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;
-
-/// Creates a new registry with all known semantic lints.
-pub fn default_lint_registry() -> LintRegistry {
-    let mut registry = LintRegistryBuilder::default();
-    register_lints(&mut registry);
-    registry.build()
-}
-
-/// Register all known semantic lints.
-pub fn register_lints(registry: &mut LintRegistryBuilder) {
-    types::register_lints(registry);
-}
--- a/crates/red_knot_python_semantic/src/lint.rs
+++ b/crates/red_knot_python_semantic/src/lint.rs
@@ -1,465 +0,0 @@
-use itertools::Itertools;
-use ruff_db::diagnostic::{LintName, Severity};
-use rustc_hash::FxHashMap;
-use std::hash::Hasher;
-use thiserror::Error;
-
-#[derive(Debug, Clone)]
-pub struct LintMetadata {
-    /// The unique identifier for the lint.
-    pub name: LintName,
-
-    /// A one-sentence summary of what the lint catches.
-    pub summary: &'static str,
-
-    /// An in depth explanation of the lint in markdown. Covers what the lint does, why it's bad and possible fixes.
-    ///
-    /// The documentation may require post-processing to be rendered correctly. For example, lines
-    /// might have leading or trailing whitespace that should be removed.
-    pub raw_documentation: &'static str,
-
-    /// The default level of the lint if the user doesn't specify one.
-    pub default_level: Level,
-
-    pub status: LintStatus,
-
-    /// The source file in which the lint is declared.
-    pub file: &'static str,
-
-    /// The 1-based line number in the source `file` where the lint is declared.
-    pub line: u32,
-}
-
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
-pub enum Level {
-    /// The lint is disabled and should not run.
-    Ignore,
-
-    /// The lint is enabled and diagnostic should have a warning severity.
-    Warn,
-
-    /// The lint is enabled and diagnostics have an error severity.
-    Error,
-}
-
-impl Level {
-    pub const fn is_error(self) -> bool {
-        matches!(self, Level::Error)
-    }
-
-    pub const fn is_warn(self) -> bool {
-        matches!(self, Level::Warn)
-    }
-
-    pub const fn is_ignore(self) -> bool {
-        matches!(self, Level::Ignore)
-    }
-}
-
-impl TryFrom<Level> for Severity {
-    type Error = ();
-
-    fn try_from(level: Level) -> Result<Self, ()> {
-        match level {
-            Level::Ignore => Err(()),
-            Level::Warn => Ok(Severity::Warning),
-            Level::Error => Ok(Severity::Error),
-        }
-    }
-}
-
-impl LintMetadata {
-    pub fn name(&self) -> LintName {
-        self.name
-    }
-
-    pub fn summary(&self) -> &str {
-        self.summary
-    }
-
-    /// Returns the documentation line by line with one leading space and all trailing whitespace removed.
-    pub fn documentation_lines(&self) -> impl Iterator<Item = &str> {
-        self.raw_documentation
-            .lines()
-            .map(|line| line.strip_prefix(' ').unwrap_or(line).trim_end())
-    }
-
-    /// Returns the documentation as a single string.
-    pub fn documentation(&self) -> String {
-        self.documentation_lines().join("\n")
-    }
-
-    pub fn default_level(&self) -> Level {
-        self.default_level
-    }
-
-    pub fn status(&self) -> &LintStatus {
-        &self.status
-    }
-
-    pub fn file(&self) -> &str {
-        self.file
-    }
-
-    pub fn line(&self) -> u32 {
-        self.line
-    }
-}
-
-#[doc(hidden)]
-pub const fn lint_metadata_defaults() -> LintMetadata {
-    LintMetadata {
-        name: LintName::of(""),
-        summary: "",
-        raw_documentation: "",
-        default_level: Level::Error,
-        status: LintStatus::preview("0.0.0"),
-        file: "",
-        line: 1,
-    }
-}
-
-#[derive(Copy, Clone, Debug)]
-pub enum LintStatus {
-    /// The lint has been added to the linter, but is not yet stable.
-    Preview {
-        /// The version in which the lint was added.
-        since: &'static str,
-    },
-
-    /// The lint is stable.
-    Stable {
-        /// The version in which the lint was stabilized.
-        since: &'static str,
-    },
-
-    /// The lint is deprecated and no longer recommended for use.
-    Deprecated {
-        /// The version in which the lint was deprecated.
-        since: &'static str,
-
-        /// The reason why the lint has been deprecated.
-        ///
-        /// This should explain why the lint has been deprecated and if there's a replacement lint that users
-        /// can use instead.
-        reason: &'static str,
-    },
-
-    /// The lint has been removed and can no longer be used.
-    Removed {
-        /// The version in which the lint was removed.
-        since: &'static str,
-
-        /// The reason why the lint has been removed.
-        reason: &'static str,
-    },
-}
-
-impl LintStatus {
-    pub const fn preview(since: &'static str) -> Self {
-        LintStatus::Preview { since }
-    }
-
-    pub const fn stable(since: &'static str) -> Self {
-        LintStatus::Stable { since }
-    }
-
-    pub const fn deprecated(since: &'static str, reason: &'static str) -> Self {
-        LintStatus::Deprecated { since, reason }
-    }
-
-    pub const fn removed(since: &'static str, reason: &'static str) -> Self {
-        LintStatus::Removed { since, reason }
-    }
-
-    pub const fn is_removed(&self) -> bool {
-        matches!(self, LintStatus::Removed { .. })
-    }
-}
-
-/// Declares a lint rule with the given metadata.
-///
-/// ```rust
-/// use red_knot_python_semantic::declare_lint;
-/// use red_knot_python_semantic::lint::{LintStatus, Level};
-///
-/// declare_lint! {
-///     /// ## What it does
-///     /// Checks for references to names that are not defined.
-///     ///
-///     /// ## Why is this bad?
-///     /// Using an undefined variable will raise a `NameError` at runtime.
-///     ///
-///     /// ## Example
-///     ///
-///     /// ```python
-///     /// print(x)  # NameError: name 'x' is not defined
-///     /// ```
-///     pub(crate) static UNRESOLVED_REFERENCE = {
-///         summary: "detects references to names that are not defined",
-///         status: LintStatus::preview("1.0.0"),
-///         default_level: Level::Warn,
-///     }
-/// }
-/// ```
-#[macro_export]
-macro_rules! declare_lint {
-    (
-        $(#[doc = $doc:literal])+
-        $vis: vis static $name: ident = {
-            summary: $summary: literal,
-            status: $status: expr,
-            // Optional properties
-            $( $key:ident: $value:expr, )*
-        }
-    ) => {
-        $( #[doc = $doc] )+
-        #[allow(clippy::needless_update)]
-        $vis static $name: $crate::lint::LintMetadata = $crate::lint::LintMetadata {
-            name: ruff_db::diagnostic::LintName::of(ruff_macros::kebab_case!($name)),
-            summary: $summary,
-            raw_documentation: concat!($($doc,)+ "\n"),
-            status: $status,
-            file: file!(),
-            line: line!(),
-            $( $key: $value, )*
-            ..$crate::lint::lint_metadata_defaults()
-        };
-    };
-}
-
-/// A unique identifier for a lint rule.
-///
-/// Implements `PartialEq`, `Eq`, and `Hash` based on the `LintMetadata` pointer
-/// for fast comparison and lookup.
-#[derive(Debug, Clone, Copy)]
-pub struct LintId {
-    definition: &'static LintMetadata,
-}
-
-impl LintId {
-    pub const fn of(definition: &'static LintMetadata) -> Self {
-        LintId { definition }
-    }
-}
-
-impl PartialEq for LintId {
-    fn eq(&self, other: &Self) -> bool {
-        std::ptr::eq(self.definition, other.definition)
-    }
-}
-
-impl Eq for LintId {}
-
-impl std::hash::Hash for LintId {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        std::ptr::hash(self.definition, state);
-    }
-}
-
-impl std::ops::Deref for LintId {
-    type Target = LintMetadata;
-
-    fn deref(&self) -> &Self::Target {
-        self.definition
-    }
-}
-
-#[derive(Default, Debug)]
-pub struct LintRegistryBuilder {
-    /// Registered lints that haven't been removed.
-    lints: Vec<LintId>,
-
-    /// Lints indexed by name, including aliases and removed rules.
-    by_name: FxHashMap<&'static str, LintEntry>,
-}
-
-impl LintRegistryBuilder {
-    #[track_caller]
-    pub fn register_lint(&mut self, lint: &'static LintMetadata) {
-        assert_eq!(
-            self.by_name.insert(&*lint.name, lint.into()),
-            None,
-            "duplicate lint registration for '{name}'",
-            name = lint.name
-        );
-
-        if !lint.status.is_removed() {
-            self.lints.push(LintId::of(lint));
-        }
-    }
-
-    #[track_caller]
-    pub fn register_alias(&mut self, from: LintName, to: &'static LintMetadata) {
-        let target = match self.by_name.get(to.name.as_str()) {
-            Some(LintEntry::Lint(target) | LintEntry::Removed(target)) => target,
-            Some(LintEntry::Alias(target)) => {
-                panic!(
-                    "lint alias {from} -> {to:?} points to another alias {target:?}",
-                    target = target.name()
-                )
-            }
-            None => panic!(
-                "lint alias {from} -> {to} points to non-registered lint",
-                to = to.name
-            ),
-        };
-
-        assert_eq!(
-            self.by_name
-                .insert(from.as_str(), LintEntry::Alias(*target)),
-            None,
-            "duplicate lint registration for '{from}'",
-        );
-    }
-
-    pub fn build(self) -> LintRegistry {
-        LintRegistry {
-            lints: self.lints,
-            by_name: self.by_name,
-        }
-    }
-}
-
-#[derive(Default, Debug)]
-pub struct LintRegistry {
-    lints: Vec<LintId>,
-    by_name: FxHashMap<&'static str, LintEntry>,
-}
-
-impl LintRegistry {
-    /// Looks up a lint by its name.
-    pub fn get(&self, code: &str) -> Result<LintId, GetLintError> {
-        match self.by_name.get(code) {
-            Some(LintEntry::Lint(metadata)) => Ok(*metadata),
-            Some(LintEntry::Alias(lint)) => {
-                if lint.status.is_removed() {
-                    Err(GetLintError::Removed(lint.name()))
-                } else {
-                    Ok(*lint)
-                }
-            }
-            Some(LintEntry::Removed(lint)) => Err(GetLintError::Removed(lint.name())),
-            None => Err(GetLintError::Unknown(code.to_string())),
-        }
-    }
-
-    /// Returns all registered, non-removed lints.
-    pub fn lints(&self) -> &[LintId] {
-        &self.lints
-    }
-
-    /// Returns an iterator over all known aliases and to their target lints.
-    ///
-    /// This iterator includes aliases that point to removed lints.
-    pub fn aliases(&self) -> impl Iterator<Item = (LintName, LintId)> + '_ {
-        self.by_name.iter().filter_map(|(key, value)| {
-            if let LintEntry::Alias(alias) = value {
-                Some((LintName::of(key), *alias))
-            } else {
-                None
-            }
-        })
-    }
-
-    /// Iterates over all removed lints.
-    pub fn removed(&self) -> impl Iterator<Item = LintId> + '_ {
-        self.by_name.iter().filter_map(|(_, value)| {
-            if let LintEntry::Removed(metadata) = value {
-                Some(*metadata)
-            } else {
-                None
-            }
-        })
-    }
-}
-
-#[derive(Error, Debug, Clone)]
-pub enum GetLintError {
-    /// The name maps to this removed lint.
-    #[error("lint {0} has been removed")]
-    Removed(LintName),
-
-    /// No lint with the given name is known.
-    #[error("unknown lint {0}")]
-    Unknown(String),
-}
-
-#[derive(Debug, PartialEq, Eq)]
-pub enum LintEntry {
-    /// An existing lint rule. Can be in preview, stable or deprecated.
-    Lint(LintId),
-    /// A lint rule that has been removed.
-    Removed(LintId),
-    Alias(LintId),
-}
-
-impl From<&'static LintMetadata> for LintEntry {
-    fn from(metadata: &'static LintMetadata) -> Self {
-        if metadata.status.is_removed() {
-            LintEntry::Removed(LintId::of(metadata))
-        } else {
-            LintEntry::Lint(LintId::of(metadata))
-        }
-    }
-}
-
-#[derive(Debug, Clone, Default)]
-pub struct RuleSelection {
-    /// Map with the severity for each enabled lint rule.
-    ///
-    /// If a rule isn't present in this map, then it should be considered disabled.
-    lints: FxHashMap<LintId, Severity>,
-}
-
-impl RuleSelection {
-    /// Creates a new rule selection from all known lints in the registry that are enabled
-    /// according to their default severity.
-    pub fn from_registry(registry: &LintRegistry) -> Self {
-        let lints = registry
-            .lints()
-            .iter()
-            .filter_map(|lint| {
-                Severity::try_from(lint.default_level())
-                    .ok()
-                    .map(|severity| (*lint, severity))
-            })
-            .collect();
-
-        RuleSelection { lints }
-    }
-
-    /// Returns an iterator over all enabled lints.
-    pub fn enabled(&self) -> impl Iterator<Item = LintId> + '_ {
-        self.lints.keys().copied()
-    }
-
-    /// Returns an iterator over all enabled lints and their severity.
-    pub fn iter(&self) -> impl ExactSizeIterator<Item = (LintId, Severity)> + '_ {
-        self.lints.iter().map(|(&lint, &severity)| (lint, severity))
-    }
-
-    /// Returns the configured severity for the lint with the given id or `None` if the lint is disabled.
-    pub fn severity(&self, lint: LintId) -> Option<Severity> {
-        self.lints.get(&lint).copied()
-    }
-
-    /// Enables `lint` and configures with the given `severity`.
-    ///
-    /// Overrides any previous configuration for the lint.
-    pub fn enable(&mut self, lint: LintId, severity: Severity) {
-        self.lints.insert(lint, severity);
-    }
-
-    /// Disables `lint` if it was previously enabled.
-    pub fn disable(&mut self, lint: LintId) {
-        self.lints.remove(&lint);
-    }
-
-    /// Merges the enabled lints from `other` into this selection.
-    ///
-    /// Lints from `other` will override any existing configuration.
-    pub fn merge(&mut self, other: &RuleSelection) {
-        self.lints.extend(other.iter());
-    }
-}
--- a/crates/red_knot_python_semantic/src/semantic_index.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index.rs
@@ -606,11 +606,24 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
        let function_table = index.symbol_table(function_scope_id);
        assert_eq!(
            names(&function_table),
-            vec!["a", "b", "c", "d", "args", "kwargs"],
+            vec!["a", "b", "c", "args", "d", "kwargs"],
        );

        let use_def = index.use_def_map(function_scope_id);
        for name in ["a", "b", "c", "d"] {
+            let binding = use_def
+                .first_public_binding(
+                    function_table
+                        .symbol_id_by_name(name)
+                        .expect("symbol exists"),
+                )
+                .unwrap();
+            assert!(matches!(
+                binding.kind(&db),
+                DefinitionKind::ParameterWithDefault(_)
+            ));
+        }
+        for name in ["args", "kwargs"] {
            let binding = use_def
                .first_public_binding(
                    function_table
@@ -620,28 +633,6 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
                .unwrap();
            assert!(matches!(binding.kind(&db), DefinitionKind::Parameter(_)));
        }
-        let args_binding = use_def
-            .first_public_binding(
-                function_table
-                    .symbol_id_by_name("args")
-                    .expect("symbol exists"),
-            )
-            .unwrap();
-        assert!(matches!(
-            args_binding.kind(&db),
-            DefinitionKind::VariadicPositionalParameter(_)
-        ));
-        let kwargs_binding = use_def
-            .first_public_binding(
-                function_table
-                    .symbol_id_by_name("kwargs")
-                    .expect("symbol exists"),
-            )
-            .unwrap();
-        assert!(matches!(
-            kwargs_binding.kind(&db),
-            DefinitionKind::VariadicKeywordParameter(_)
-        ));
    }

    #[test]
@@ -663,38 +654,25 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
        let lambda_table = index.symbol_table(lambda_scope_id);
        assert_eq!(
            names(&lambda_table),
-            vec!["a", "b", "c", "d", "args", "kwargs"],
+            vec!["a", "b", "c", "args", "d", "kwargs"],
        );

        let use_def = index.use_def_map(lambda_scope_id);
        for name in ["a", "b", "c", "d"] {
+            let binding = use_def
+                .first_public_binding(lambda_table.symbol_id_by_name(name).expect("symbol exists"))
+                .unwrap();
+            assert!(matches!(
+                binding.kind(&db),
+                DefinitionKind::ParameterWithDefault(_)
+            ));
+        }
+        for name in ["args", "kwargs"] {
            let binding = use_def
                .first_public_binding(lambda_table.symbol_id_by_name(name).expect("symbol exists"))
                .unwrap();
            assert!(matches!(binding.kind(&db), DefinitionKind::Parameter(_)));
        }
-        let args_binding = use_def
-            .first_public_binding(
-                lambda_table
-                    .symbol_id_by_name("args")
-                    .expect("symbol exists"),
-            )
-            .unwrap();
-        assert!(matches!(
-            args_binding.kind(&db),
-            DefinitionKind::VariadicPositionalParameter(_)
-        ));
-        let kwargs_binding = use_def
-            .first_public_binding(
-                lambda_table
-                    .symbol_id_by_name("kwargs")
-                    .expect("symbol exists"),
-            )
-            .unwrap();
-        assert!(matches!(
-            kwargs_binding.kind(&db),
-            DefinitionKind::VariadicKeywordParameter(_)
-        ));
    }

    /// Test case to validate that the comprehension scope is correctly identified and that the target
--- a/crates/red_knot_python_semantic/src/semantic_index/builder.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/builder.rs
@@ -9,7 +9,7 @@ use ruff_index::IndexVec;
 use ruff_python_ast as ast;
 use ruff_python_ast::name::Name;
 use ruff_python_ast::visitor::{walk_expr, walk_pattern, walk_stmt, Visitor};
-use ruff_python_ast::{BoolOp, Expr};
+use ruff_python_ast::{AnyParameterRef, BoolOp, Expr};

 use crate::ast_node_ref::AstNodeRef;
 use crate::semantic_index::ast_ids::node_key::ExpressionNodeKey;
@@ -479,35 +479,21 @@ impl<'db> SemanticIndexBuilder<'db> {
        self.pop_scope();
    }

-    fn declare_parameters(&mut self, parameters: &'db ast::Parameters) {
-        for parameter in parameters.iter_non_variadic_params() {
-            self.declare_parameter(parameter);
-        }
-        if let Some(vararg) = parameters.vararg.as_ref() {
-            let symbol = self.add_symbol(vararg.name.id().clone());
-            self.add_definition(
-                symbol,
-                DefinitionNodeRef::VariadicPositionalParameter(vararg),
-            );
-        }
-        if let Some(kwarg) = parameters.kwarg.as_ref() {
-            let symbol = self.add_symbol(kwarg.name.id().clone());
-            self.add_definition(symbol, DefinitionNodeRef::VariadicKeywordParameter(kwarg));
-        }
-    }
-
-    fn declare_parameter(&mut self, parameter: &'db ast::ParameterWithDefault) {
-        let symbol = self.add_symbol(parameter.parameter.name.id().clone());
+    fn declare_parameter(&mut self, parameter: AnyParameterRef<'db>) {
+        let symbol = self.add_symbol(parameter.name().id().clone());

        let definition = self.add_definition(symbol, parameter);

-        // Insert a mapping from the inner Parameter node to the same definition.
-        // This ensures that calling `HasTy::ty` on the inner parameter returns
-        // a valid type (and doesn't panic)
-        let existing_definition = self
-            .definitions_by_node
-            .insert((&parameter.parameter).into(), definition);
-        debug_assert_eq!(existing_definition, None);
+        if let AnyParameterRef::NonVariadic(with_default) = parameter {
+            // Insert a mapping from the parameter to the same definition.
+            // This ensures that calling `HasTy::ty` on the inner parameter returns
+            // a valid type (and doesn't panic)
+            let existing_definition = self.definitions_by_node.insert(
+                DefinitionNodeRef::from(AnyParameterRef::Variadic(&with_default.parameter)).key(),
+                definition,
+            );
+            debug_assert_eq!(existing_definition, None);
+        }
    }

    pub(super) fn build(mut self) -> SemanticIndex<'db> {
@@ -570,40 +556,34 @@ where
    fn visit_stmt(&mut self, stmt: &'ast ast::Stmt) {
        match stmt {
            ast::Stmt::FunctionDef(function_def) => {
-                let ast::StmtFunctionDef {
-                    decorator_list,
-                    parameters,
-                    type_params,
-                    name,
-                    returns,
-                    body,
-                    is_async: _,
-                    range: _,
-                } = function_def;
-                for decorator in decorator_list {
+                for decorator in &function_def.decorator_list {
                    self.visit_decorator(decorator);
                }

                self.with_type_params(
                    NodeWithScopeRef::FunctionTypeParameters(function_def),
-                    type_params.as_deref(),
+                    function_def.type_params.as_deref(),
                    |builder| {
-                        builder.visit_parameters(parameters);
-                        if let Some(returns) = returns {
-                            builder.visit_annotation(returns);
+                        builder.visit_parameters(&function_def.parameters);
+                        if let Some(expr) = &function_def.returns {
+                            builder.visit_annotation(expr);
                        }

                        builder.push_scope(NodeWithScopeRef::Function(function_def));

-                        builder.declare_parameters(parameters);
+                        // Add symbols and definitions for the parameters to the function scope.
+                        for parameter in &*function_def.parameters {
+                            builder.declare_parameter(parameter);
+                        }

-                        builder.visit_body(body);
+                        builder.visit_body(&function_def.body);
                        builder.pop_scope()
                    },
                );
                // The default value of the parameters needs to be evaluated in the
                // enclosing scope.
-                for default in parameters
+                for default in function_def
+                    .parameters
                    .iter_non_variadic_params()
                    .filter_map(|param| param.default.as_deref())
                {
@@ -612,7 +592,7 @@ where
                // The symbol for the function name itself has to be evaluated
                // at the end to match the runtime evaluation of parameter defaults
                // and return-type annotations.
-                let symbol = self.add_symbol(name.id.clone());
+                let symbol = self.add_symbol(function_def.name.id.clone());
                self.add_definition(symbol, function_def);
            }
            ast::Stmt::ClassDef(class) => {
@@ -1199,8 +1179,10 @@ where
                self.push_scope(NodeWithScopeRef::Lambda(lambda));

                // Add symbols and definitions for the parameters to the lambda scope.
-                if let Some(parameters) = lambda.parameters.as_ref() {
-                    self.declare_parameters(parameters);
+                if let Some(parameters) = &lambda.parameters {
+                    for parameter in parameters {
+                        self.declare_parameter(parameter);
+                    }
                }

                self.visit_expr(lambda.body.as_ref());
--- a/crates/red_knot_python_semantic/src/semantic_index/definition.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/definition.rs
@@ -89,9 +89,7 @@ pub(crate) enum DefinitionNodeRef<'a> {
    AnnotatedAssignment(&'a ast::StmtAnnAssign),
    AugmentedAssignment(&'a ast::StmtAugAssign),
    Comprehension(ComprehensionDefinitionNodeRef<'a>),
-    VariadicPositionalParameter(&'a ast::Parameter),
-    VariadicKeywordParameter(&'a ast::Parameter),
-    Parameter(&'a ast::ParameterWithDefault),
+    Parameter(ast::AnyParameterRef<'a>),
    WithItem(WithItemDefinitionNodeRef<'a>),
    MatchPattern(MatchPatternDefinitionNodeRef<'a>),
    ExceptHandler(ExceptHandlerDefinitionNodeRef<'a>),
@@ -190,8 +188,8 @@ impl<'a> From<ComprehensionDefinitionNodeRef<'a>> for DefinitionNodeRef<'a> {
    }
 }

-impl<'a> From<&'a ast::ParameterWithDefault> for DefinitionNodeRef<'a> {
-    fn from(node: &'a ast::ParameterWithDefault) -> Self {
+impl<'a> From<ast::AnyParameterRef<'a>> for DefinitionNodeRef<'a> {
+    fn from(node: ast::AnyParameterRef<'a>) -> Self {
        Self::Parameter(node)
    }
 }
@@ -317,15 +315,14 @@ impl<'db> DefinitionNodeRef<'db> {
                first,
                is_async,
            }),
-            DefinitionNodeRef::VariadicPositionalParameter(parameter) => {
-                DefinitionKind::VariadicPositionalParameter(AstNodeRef::new(parsed, parameter))
-            }
-            DefinitionNodeRef::VariadicKeywordParameter(parameter) => {
-                DefinitionKind::VariadicKeywordParameter(AstNodeRef::new(parsed, parameter))
-            }
-            DefinitionNodeRef::Parameter(parameter) => {
-                DefinitionKind::Parameter(AstNodeRef::new(parsed, parameter))
-            }
+            DefinitionNodeRef::Parameter(parameter) => match parameter {
+                ast::AnyParameterRef::Variadic(parameter) => {
+                    DefinitionKind::Parameter(AstNodeRef::new(parsed, parameter))
+                }
+                ast::AnyParameterRef::NonVariadic(parameter) => {
+                    DefinitionKind::ParameterWithDefault(AstNodeRef::new(parsed, parameter))
+                }
+            },
            DefinitionNodeRef::WithItem(WithItemDefinitionNodeRef {
                node,
                target,
@@ -387,9 +384,10 @@ impl<'db> DefinitionNodeRef<'db> {
                is_async: _,
            }) => target.into(),
            Self::Comprehension(ComprehensionDefinitionNodeRef { target, .. }) => target.into(),
-            Self::VariadicPositionalParameter(node) => node.into(),
-            Self::VariadicKeywordParameter(node) => node.into(),
-            Self::Parameter(node) => node.into(),
+            Self::Parameter(node) => match node {
+                ast::AnyParameterRef::Variadic(parameter) => parameter.into(),
+                ast::AnyParameterRef::NonVariadic(parameter) => parameter.into(),
+            },
            Self::WithItem(WithItemDefinitionNodeRef {
                node: _,
                target,
@@ -454,9 +452,8 @@ pub enum DefinitionKind<'db> {
    AugmentedAssignment(AstNodeRef<ast::StmtAugAssign>),
    For(ForStmtDefinitionKind),
    Comprehension(ComprehensionDefinitionKind),
-    VariadicPositionalParameter(AstNodeRef<ast::Parameter>),
-    VariadicKeywordParameter(AstNodeRef<ast::Parameter>),
-    Parameter(AstNodeRef<ast::ParameterWithDefault>),
+    Parameter(AstNodeRef<ast::Parameter>),
+    ParameterWithDefault(AstNodeRef<ast::ParameterWithDefault>),
    WithItem(WithItemDefinitionKind),
    MatchPattern(MatchPatternDefinitionKind),
    ExceptHandler(ExceptHandlerDefinitionKind),
@@ -478,8 +475,7 @@ impl DefinitionKind<'_> {
            | DefinitionKind::ParamSpec(_)
            | DefinitionKind::TypeVarTuple(_) => DefinitionCategory::DeclarationAndBinding,
            // a parameter always binds a value, but is only a declaration if annotated
-            DefinitionKind::VariadicPositionalParameter(parameter)
-            | DefinitionKind::VariadicKeywordParameter(parameter) => {
+            DefinitionKind::Parameter(parameter) => {
                if parameter.annotation.is_some() {
                    DefinitionCategory::DeclarationAndBinding
                } else {
@@ -487,7 +483,7 @@ impl DefinitionKind<'_> {
                }
            }
            // presence of a default is irrelevant, same logic as for a no-default parameter
-            DefinitionKind::Parameter(parameter_with_default) => {
+            DefinitionKind::ParameterWithDefault(parameter_with_default) => {
                if parameter_with_default.parameter.annotation.is_some() {
                    DefinitionCategory::DeclarationAndBinding
                } else {
@@ -747,15 +743,6 @@ impl From<&ast::ParameterWithDefault> for DefinitionNodeKey {
    }
 }

-impl From<ast::AnyParameterRef<'_>> for DefinitionNodeKey {
-    fn from(value: ast::AnyParameterRef) -> Self {
-        Self(match value {
-            ast::AnyParameterRef::Variadic(node) => NodeKey::from_node(node),
-            ast::AnyParameterRef::NonVariadic(node) => NodeKey::from_node(node),
-        })
-    }
-}
-
 impl From<&ast::Identifier> for DefinitionNodeKey {
    fn from(identifier: &ast::Identifier) -> Self {
        Self(NodeKey::from_node(identifier))
--- a/crates/red_knot_python_semantic/src/semantic_index/use_def.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/use_def.rs
@@ -47,7 +47,7 @@
 //! The **declared type** represents the code author's declaration (usually through a type
 //! annotation) that a given variable should not be assigned any type outside the declared type. In
 //! our model, declared types are also control-flow-sensitive; we allow the code author to
-//! explicitly redeclare the same variable with a different type. So for a given binding of a
+//! explicitly re-declare the same variable with a different type. So for a given binding of a
 //! variable, we will want to ask which declarations of that variable can reach that binding, in
 //! order to determine whether the binding is permitted, or should be a type error. For example:
 //!
@@ -62,7 +62,7 @@
 //! assignable to `str`. This is the purpose of declared types: they prevent accidental assignment
 //! of the wrong type to a variable.
 //!
-//! But in some cases it is useful to "shadow" or "redeclare" a variable with a new type, and we
+//! But in some cases it is useful to "shadow" or "re-declare" a variable with a new type, and we
 //! permit this, as long as it is done with an explicit re-annotation. So `path: Path =
 //! Path(path)`, with the explicit `: Path` annotation, is permitted.
 //!
--- a/crates/red_knot_python_semantic/src/semantic_model.rs
+++ b/crates/red_knot_python_semantic/src/semantic_model.rs
@@ -166,15 +166,31 @@ impl_binding_has_ty!(ast::ParameterWithDefault);
 mod tests {
    use ruff_db::files::system_path_to_file;
    use ruff_db::parsed::parsed_module;
+    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};

-    use crate::db::tests::TestDbBuilder;
-    use crate::{HasTy, SemanticModel};
+    use crate::db::tests::TestDb;
+    use crate::program::{Program, SearchPathSettings};
+    use crate::python_version::PythonVersion;
+    use crate::{HasTy, ProgramSettings, SemanticModel};
+
+    fn setup_db<'a>(files: impl IntoIterator<Item = (&'a str, &'a str)>) -> anyhow::Result<TestDb> {
+        let mut db = TestDb::new();
+        db.write_files(files)?;
+
+        Program::from_settings(
+            &db,
+            &ProgramSettings {
+                target_version: PythonVersion::default(),
+                search_paths: SearchPathSettings::new(SystemPathBuf::from("/src")),
+            },
+        )?;
+
+        Ok(db)
+    }

    #[test]
    fn function_ty() -> anyhow::Result<()> {
-        let db = TestDbBuilder::new()
-            .with_file("/src/foo.py", "def test(): pass")
-            .build()?;
+        let db = setup_db([("/src/foo.py", "def test(): pass")])?;

        let foo = system_path_to_file(&db, "/src/foo.py").unwrap();

@@ -191,9 +207,7 @@ mod tests {

    #[test]
    fn class_ty() -> anyhow::Result<()> {
-        let db = TestDbBuilder::new()
-            .with_file("/src/foo.py", "class Test: pass")
-            .build()?;
+        let db = setup_db([("/src/foo.py", "class Test: pass")])?;

        let foo = system_path_to_file(&db, "/src/foo.py").unwrap();

@@ -210,10 +224,10 @@ mod tests {

    #[test]
    fn alias_ty() -> anyhow::Result<()> {
-        let db = TestDbBuilder::new()
-            .with_file("/src/foo.py", "class Test: pass")
-            .with_file("/src/bar.py", "from foo import Test")
-            .build()?;
+        let db = setup_db([
+            ("/src/foo.py", "class Test: pass"),
+            ("/src/bar.py", "from foo import Test"),
+        ])?;

        let bar = system_path_to_file(&db, "/src/bar.py").unwrap();

--- a/crates/red_knot_python_semantic/src/symbol.rs
+++ b/crates/red_knot_python_semantic/src/symbol.rs
@@ -90,7 +90,7 @@ impl<'db> Symbol<'db> {
 #[cfg(test)]
 mod tests {
    use super::*;
-    use crate::db::tests::setup_db;
+    use crate::types::tests::setup_db;

    #[test]
    fn test_symbol_or_fall_back_to() {
--- a/crates/red_knot_python_semantic/src/types.rs
+++ b/crates/red_knot_python_semantic/src/types.rs
--- a/Show More
+++ b/Show More