Update more snapshots

Upgrade annotation snippet
Add basic red knot benchmark (#13026 )
2024-08-23 11:43:37 +02:00 · 2024-08-23 11:28:59 +02:00 · 2024-08-23 08:22:42 +02:00 · 2024-08-23 08:22:12 +02:00 · 2024-08-22 13:27:15 -07:00 · 2024-08-22 07:59:13 -07:00
1752 changed files with 38382 additions and 27158 deletions
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -36,30 +36,28 @@ jobs:
          version="${{ (inputs.plan != '' && fromJson(inputs.plan).announcement_tag) || inputs.ref }}"
          # if version is missing, exit with error
          if [[ -z "$version" ]]; then
-            echo "Can't build docs without a version."
-            exit 1
+          echo "Can't build docs without a version."
+          exit 1
          fi

          # Use version as display name for now
          display_name="$version"

-          # Extract the major and minor part of the version for the docs
-          docs_version="$(echo -n "$version" | cut -d "." -f 1-2)"
-
-          echo "version=$version" >> "$GITHUB_ENV"
-          echo "docs_version=$docs_version" >> "$GITHUB_ENV"
-          echo "display_name=$display_name" >> "$GITHUB_ENV"
+          echo "version=$version" >> $GITHUB_ENV
+          echo "display_name=$display_name" >> $GITHUB_ENV

      - name: "Set branch name"
        run: |
+          version="${{ env.version }}"
+          display_name="${{ env.display_name }}"
          timestamp="$(date +%s)"

-          # Create `branch_display_name` from `display_name` by replacing all
+          # create branch_display_name from display_name by replacing all
          # characters disallowed in git branch names with hyphens
-          branch_display_name="$(echo -n "$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" >> "$GITHUB_ENV"
+          echo "branch_name=update-docs-$branch_display_name-$timestamp" >> $GITHUB_ENV
+          echo "timestamp=$timestamp" >> $GITHUB_ENV

      - name: "Add SSH key"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
@@ -72,7 +70,7 @@ jobs:

      - uses: Swatinem/rust-cache@v2

-      - name: "Install insiders dependencies"
+      - name: "Install Insiders dependencies"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
        run: pip install -r docs/requirements-insiders.txt

@@ -80,86 +78,74 @@ jobs:
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
        run: pip install -r docs/requirements.txt

-      - name: "Fetch docs repo"
-        run: |
-          remote_name="astral-docs"
-
-          git remote add "$remote_name" https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git
-          git fetch astral-docs "main:$branch_name"
-
-          echo "remote_name=$remote_name" >> "$GITHUB_ENV"
-
-      - name: "Configure git"
-        run: |
-          git config user.name "astral-docs-bot"
-          git config user.email "176161322+astral-docs-bot@users.noreply.github.com"
-
-      - name: "Transform README and generate docs"
+      - name: "Copy README File"
        run: |
          python scripts/transform_readme.py --target mkdocs
          python scripts/generate_mkdocs.py

      - name: "Build Insiders docs"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: |
-          mike deploy \
-            --remote "$remote_name" \
-            --branch "$branch_name" \
-            --message "Update ruff documentation for $version" \
-            --config-file mkdocs.insiders.yml \
-            --update-aliases \
-            --push \
-            "$docs_version" latest
+        run: mkdocs build --strict -f mkdocs.insiders.yml

      - name: "Build docs"
        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
+        run: mkdocs build --strict -f mkdocs.public.yml
+
+      - name: "Clone docs repo"
        run: |
-          mike deploy \
-            --remote "$remote_name" \
-            --branch "$branch_name" \
-            --message "Update ruff documentation for $version" \
-            --config-file mkdocs.public.yml \
-            --update-aliases \
-            --push \
-            "$docs_version" latest
+          version="${{ env.version }}"
+          git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
+
+      - name: "Copy docs"
+        run: rm -rf astral-docs/site/ruff && mkdir -p astral-docs/site && cp -r site/ruff astral-docs/site/
+
+      - name: "Commit docs"
+        working-directory: astral-docs
+        run: |
+          branch_name="${{ env.branch_name }}"
+
+          git config user.name "astral-docs-bot"
+          git config user.email "176161322+astral-docs-bot@users.noreply.github.com"
+
+          git checkout -b $branch_name
+          git add site/ruff
+          git commit -m "Update ruff documentation for $version"

      - name: "Create Pull Request"
+        working-directory: astral-docs
        env:
          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
        run: |
-          # Set the docs repository
-          astral_docs_repo="astral-sh/docs"
+          version="${{ env.version }}"
+          display_name="${{ env.display_name }}"
+          branch_name="${{ env.branch_name }}"

-          # Set the PR title
+          # set the PR title
          pull_request_title="Update ruff documentation for $display_name"

          # Delete any existing pull requests that are open for this version
-          # by checking against `pull_request_title` because the new PR will
+          # by checking against pull_request_title because the new PR will
          # supersede the old one.
-          gh pr list \
-            --state open \
-            --json title,number \
-            --jq '.[] | select(.title == "$pull_request_title") | .number' \
-            --repo "$astral_docs_repo" | \
-              xargs -I {} gh pr close {}
+          gh pr list --state open --json title --jq '.[] | select(.title == "$pull_request_title") | .number' | \
+            xargs -I {} gh pr close {}

-          # Create the PR, the branch has already been pushed by `mike`
-          gh pr create --base main --head "$branch_name" \
+          # push the branch to GitHub
+          git push origin $branch_name
+
+          # create the PR
+          gh pr create --base main --head $branch_name \
            --title "$pull_request_title" \
            --body "Automated documentation update for $display_name" \
-            --label "documentation" \
-            --repo "$astral_docs_repo"
+            --label "documentation"

-      # TODO(dhruvmanila): Uncomment once a patch and minor release are done, thus
-      # confirming that it works as intended
-      #
-      # - name: "Merge Pull Request"
-      #   if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-      #   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 --repo "astral-sh/docs"
+      - name: "Merge Pull Request"
+        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
+        working-directory: astral-docs
+        env:
+          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
+        run: |
+          branch_name="${{ env.branch_name }}"
+          # auto-merge the PR if the build was triggered by a release. Manual builds should be reviewed by a human.
+          # give the PR a few seconds to be created before trying to auto-merge it
+          sleep 10
+          gh pr merge --squash $branch_name
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -6,6 +6,8 @@ exclude: |
    crates/red_knot_workspace/resources/.*|
    crates/ruff_linter/resources/.*|
    crates/ruff_linter/src/rules/.*/snapshots/.*|
+    crates/ruff_notebook/resources/.*|
+    crates/ruff_server/resources/.*|
    crates/ruff/resources/.*|
    crates/ruff_python_formatter/resources/.*|
    crates/ruff_python_formatter/tests/snapshots/.*|
@@ -15,7 +17,7 @@ exclude: |

 repos:
  - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.18
+    rev: v0.19
    hooks:
      - id: validate-pyproject

@@ -57,7 +59,7 @@ repos:
        pass_filenames: false # This makes it a lot faster

  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.5.7
+    rev: v0.6.1
    hooks:
      - id: ruff-format
      - id: ruff
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,39 @@
 # Changelog

+## 0.6.2
+
+### Preview features
+
+- \[`flake8-simplify`\] Extend `open-file-with-context-handler` to work with other standard-library IO modules (`SIM115`) ([#12959](https://github.com/astral-sh/ruff/pull/12959))
+- \[`ruff`\] Avoid `unused-async` for functions with FastAPI route decorator (`RUF029`) ([#12938](https://github.com/astral-sh/ruff/pull/12938))
+- \[`ruff`\] Ignore `fstring-missing-syntax` (`RUF027`) for `fastAPI` paths ([#12939](https://github.com/astral-sh/ruff/pull/12939))
+- \[`ruff`\] Implement check for Decimal called with a float literal (RUF032) ([#12909](https://github.com/astral-sh/ruff/pull/12909))
+
+### Rule changes
+
+- \[`flake8-bugbear`\] Update diagnostic message when expression is at the end of function (`B015`) ([#12944](https://github.com/astral-sh/ruff/pull/12944))
+- \[`flake8-pyi`\] Skip type annotations in `string-or-bytes-too-long` (`PYI053`) ([#13002](https://github.com/astral-sh/ruff/pull/13002))
+- \[`flake8-type-checking`\] Always recognise relative imports as first-party ([#12994](https://github.com/astral-sh/ruff/pull/12994))
+- \[`flake8-unused-arguments`\] Ignore unused arguments on stub functions (`ARG001`) ([#12966](https://github.com/astral-sh/ruff/pull/12966))
+- \[`pylint`\] Ignore augmented assignment for `self-cls-assignment` (`PLW0642`) ([#12957](https://github.com/astral-sh/ruff/pull/12957))
+
+### Server
+
+- Show full context in error log messages ([#13029](https://github.com/astral-sh/ruff/pull/13029))
+
+### Bug fixes
+
+- \[`pep8-naming`\] Don't flag `from` imports following conventional import names (`N817`) ([#12946](https://github.com/astral-sh/ruff/pull/12946))
+- \[`pylint`\] - Allow `__new__` methods to have `cls` as their first argument even if decorated with `@staticmethod` for `bad-staticmethod-argument` (`PLW0211`) ([#12958](https://github.com/astral-sh/ruff/pull/12958))
+
+### Documentation
+
+- Add `hyperfine` installation instructions; update `hyperfine` code samples ([#13034](https://github.com/astral-sh/ruff/pull/13034))
+- Expand note to use Ruff with other language server in Kate ([#12806](https://github.com/astral-sh/ruff/pull/12806))
+- Update example for `PT001` as per the new default behavior ([#13019](https://github.com/astral-sh/ruff/pull/13019))
+- \[`perflint`\] Improve docs for `try-except-in-loop` (`PERF203`) ([#12947](https://github.com/astral-sh/ruff/pull/12947))
+- \[`pydocstyle`\] Add reference to `lint.pydocstyle.ignore-decorators` setting to rule docs ([#12996](https://github.com/astral-sh/ruff/pull/12996))
+
 ## 0.6.1

 This is a hotfix release to address an issue with `ruff-pre-commit`. In v0.6,
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -2,35 +2,6 @@

 Welcome! We're happy to have you here. Thank you in advance for your contribution to Ruff.

- [The Basics](#the-basics)
-    - [Prerequisites](#prerequisites)
-    - [Development](#development)
-    - [Project Structure](#project-structure)
-    - [Example: Adding a new lint rule](#example-adding-a-new-lint-rule)
-        - [Rule naming convention](#rule-naming-convention)
-        - [Rule testing: fixtures and snapshots](#rule-testing-fixtures-and-snapshots)
-    - [Example: Adding a new configuration option](#example-adding-a-new-configuration-option)
- [MkDocs](#mkdocs)
- [Release Process](#release-process)
-    - [Creating a new release](#creating-a-new-release)
- [Ecosystem CI](#ecosystem-ci)
- [Benchmarking and Profiling](#benchmarking-and-profiling)
-    - [CPython Benchmark](#cpython-benchmark)
-    - [Microbenchmarks](#microbenchmarks)
-        - [Benchmark-driven Development](#benchmark-driven-development)
-        - [PR Summary](#pr-summary)
-        - [Tips](#tips)
-    - [Profiling Projects](#profiling-projects)
-        - [Linux](#linux)
-        - [Mac](#mac)
- [`cargo dev`](#cargo-dev)
- [Subsystems](#subsystems)
-    - [Compilation Pipeline](#compilation-pipeline)
-    - [Import Categorization](#import-categorization)
-        - [Project root](#project-root)
-        - [Package root](#package-root)
-        - [Import categorization](#import-categorization-1)
-
 ## The Basics

 Ruff welcomes contributions in the form of pull requests.
@@ -333,22 +304,34 @@ even patch releases may contain [non-backwards-compatible changes](https://semve
 ### Creating a new release

 1. Install `uv`: `curl -LsSf https://astral.sh/uv/install.sh | sh`
+
 1. Run `./scripts/release.sh`; this command will:
+
    - Generate a temporary virtual environment with `rooster`
    - Generate a changelog entry in `CHANGELOG.md`
    - Update versions in `pyproject.toml` and `Cargo.toml`
    - Update references to versions in the `README.md` and documentation
    - Display contributors for the release
+
 1. The changelog should then be editorialized for consistency
+
    - Often labels will be missing from pull requests they will need to be manually organized into the proper section
    - Changes should be edited to be user-facing descriptions, avoiding internal details
+
 1. Highlight any breaking changes in `BREAKING_CHANGES.md`
+
 1. Run `cargo check`. This should update the lock file with new versions.
+
 1. Create a pull request with the changelog and version updates
+
 1. Merge the PR
+
 1. Run the [release workflow](https://github.com/astral-sh/ruff/actions/workflows/release.yml) with:
+
    - The new version number (without starting `v`)
+
 1. The release workflow will do the following:
+
    1. Build all the assets. If this fails (even though we tested in step 4), we haven't tagged or
        uploaded anything, you can restart after pushing a fix. If you just need to rerun the build,
        make sure you're [re-running all the failed
@@ -359,14 +342,25 @@ even patch releases may contain [non-backwards-compatible changes](https://semve
    1. Attach artifacts to draft GitHub release
    1. Trigger downstream repositories. This can fail non-catastrophically, as we can run any
        downstream jobs manually if needed.
+
 1. Verify the GitHub release:
+
    1. The Changelog should match the content of `CHANGELOG.md`
    1. Append the contributors from the `scripts/release.sh` script
+
 1. If needed, [update the schemastore](https://github.com/astral-sh/ruff/blob/main/scripts/update_schemastore.py).
+
    1. One can determine if an update is needed when
        `git diff old-version-tag new-version-tag -- ruff.schema.json` returns a non-empty diff.
    1. Once run successfully, you should follow the link in the output to create a PR.
-1. If needed, update the `ruff-lsp` and `ruff-vscode` repositories.
+
+1. If needed, update the [`ruff-lsp`](https://github.com/astral-sh/ruff-lsp) and
+    [`ruff-vscode`](https://github.com/astral-sh/ruff-vscode) repositories and follow
+    the release instructions in those repositories. `ruff-lsp` should always be updated
+    before `ruff-vscode`.
+
+    This step is generally not required for a patch release, but should always be done
+    for a minor release.

 ## Ecosystem CI

@@ -389,7 +383,7 @@ We have several ways of benchmarking and profiling Ruff:
 - Microbenchmarks which run the linter or the formatter on individual files. These run on pull requests.
 - Profiling the linter on either the microbenchmarks or entire projects

-> \[!NOTE\]
+> **Note**
 > When running benchmarks, ensure that your CPU is otherwise idle (e.g., close any background
 > applications, like web browsers). You may also want to switch your CPU to a "performance"
 > mode, if it exists, especially when benchmarking short-lived processes.
@@ -403,12 +397,18 @@ which makes it a good target for benchmarking.
 git clone --branch 3.10 https://github.com/python/cpython.git crates/ruff_linter/resources/test/cpython
 ```

+Install `hyperfine`:
+
+```shell
+cargo install hyperfine
+```
+
 To benchmark the release build:

 ```shell
 cargo build --release && hyperfine --warmup 10 \
-  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
-  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ -e"
+  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
+  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ -e"

 Benchmark 1: ./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache
  Time (mean ± σ):     293.8 ms ±   3.2 ms    [User: 2384.6 ms, System: 90.3 ms]
@@ -427,7 +427,7 @@ To benchmark against the ecosystem's existing tools:

 ```shell
 hyperfine --ignore-failure --warmup 5 \
-  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
+  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
  "pyflakes crates/ruff_linter/resources/test/cpython" \
  "autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython" \
  "pycodestyle crates/ruff_linter/resources/test/cpython" \
@@ -473,7 +473,7 @@ To benchmark a subset of rules, e.g. `LineTooLong` and `DocLineTooLong`:

 ```shell
 cargo build --release && hyperfine --warmup 10 \
-  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
+  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
 ```

 You can run `poetry install` from `./scripts/benchmarks` to create a working environment for the
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -71,12 +71,12 @@ checksum = "c7021ce4924a3f25f802b2cccd1af585e39ea1a363a1aa2e72afe54b67a3a7a7"

 [[package]]
 name = "annotate-snippets"
-version = "0.9.2"
+version = "0.11.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ccaf7e9dfbb6ab22c82e473cd1a8a7bd313c19a5b7e40970f3d89ef5a5c9e81e"
+checksum = "24e35ed54e5ea7997c14ed4c70ba043478db1112e98263b3b035907aa197d991"
 dependencies = [
+ "anstyle",
 "unicode-width",
- "yansi-term",
 ]

 [[package]]
@@ -1926,6 +1926,7 @@ dependencies = [
 "ruff_db",
 "ruff_index",
 "ruff_python_ast",
+ "ruff_python_literal",
 "ruff_python_parser",
 "ruff_python_stdlib",
 "ruff_source_file",
@@ -1935,6 +1936,7 @@ dependencies = [
 "smallvec",
 "static_assertions",
 "tempfile",
+ "thiserror",
 "tracing",
 "walkdir",
 "zip",
@@ -1950,10 +1952,8 @@ dependencies = [
 "libc",
 "lsp-server",
 "lsp-types",
- "red_knot_python_semantic",
 "red_knot_workspace",
 "ruff_db",
- "ruff_linter",
 "ruff_notebook",
 "ruff_python_ast",
 "ruff_source_file",
@@ -1996,7 +1996,6 @@ dependencies = [
 "ruff_text_size",
 "rustc-hash 2.0.0",
 "salsa",
- "thiserror",
 "tracing",
 ]

@@ -2090,7 +2089,7 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.6.1"
+version = "0.6.2"
 dependencies = [
 "anyhow",
 "argfile",
@@ -2282,10 +2281,10 @@ dependencies = [

 [[package]]
 name = "ruff_linter"
-version = "0.6.1"
+version = "0.6.2"
 dependencies = [
 "aho-corasick",
- "annotate-snippets 0.9.2",
+ "annotate-snippets 0.11.4",
 "anyhow",
 "bitflags 2.6.0",
 "chrono",
@@ -2471,7 +2470,7 @@ dependencies = [
 name = "ruff_python_parser"
 version = "0.0.0"
 dependencies = [
- "annotate-snippets 0.9.2",
+ "annotate-snippets 0.11.4",
 "anyhow",
 "bitflags 2.6.0",
 "bstr",
@@ -2602,7 +2601,7 @@ dependencies = [

 [[package]]
 name = "ruff_wasm"
-version = "0.6.1"
+version = "0.6.2"
 dependencies = [
 "console_error_panic_hook",
 "console_log",
@@ -2742,7 +2741,7 @@ checksum = "e86697c916019a8588c99b5fac3cead74ec0b4b819707a682fd4d23fa0ce1ba1"
 [[package]]
 name = "salsa"
 version = "0.18.0"
-source = "git+https://github.com/MichaReiser/salsa.git?tag=red-knot-0.0.1#ece083e15b79f155f9e4368ec1318cec9a08d88b"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"
 dependencies = [
 "append-only-vec",
 "arc-swap",
@@ -2762,12 +2761,12 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.1.0"
-source = "git+https://github.com/MichaReiser/salsa.git?tag=red-knot-0.0.1#ece083e15b79f155f9e4368ec1318cec9a08d88b"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"

 [[package]]
 name = "salsa-macros"
 version = "0.18.0"
-source = "git+https://github.com/MichaReiser/salsa.git?tag=red-knot-0.0.1#ece083e15b79f155f9e4368ec1318cec9a08d88b"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"
 dependencies = [
 "heck",
 "proc-macro2",
@@ -3906,15 +3905,6 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09041cd90cf85f7f8b2df60c646f853b7f535ce68f85244eb6731cf89fa498ec"

-[[package]]
-name = "yansi-term"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe5c30ade05e61656247b2e334a031dfd0cc466fadef865bdcdea8d537951bf1"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "zerocopy"
 version = "0.7.32"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -40,7 +40,7 @@ red_knot_server = { path = "crates/red_knot_server" }
 red_knot_workspace = { path = "crates/red_knot_workspace" }

 aho-corasick = { version = "1.1.3" }
-annotate-snippets = { version = "0.9.2", features = ["color"] }
+annotate-snippets = { version = "0.11.4" }
 anyhow = { version = "1.0.80" }
 argfile = { version = "0.2.0" }
 bincode = { version = "1.3.3" }
@@ -108,7 +108,7 @@ rand = { version = "0.8.5" }
 rayon = { version = "1.10.0" }
 regex = { version = "1.10.2" }
 rustc-hash = { version = "2.0.0" }
-salsa = { git = "https://github.com/MichaReiser/salsa.git", tag = "red-knot-0.0.1" }
+salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "f608ff8b24f07706492027199f51132244034f29" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
--- a/README.md
+++ b/README.md
@@ -136,8 +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/0.6.1/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.6.1/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.6.2/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.6.2/install.ps1 | iex"
 ```

 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -170,7 +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: v0.6.1
+  rev: v0.6.2
  hooks:
    # Run the linter.
    - id: ruff
--- a/crates/red_knot/src/logging.rs
+++ b/crates/red_knot/src/logging.rs
@@ -5,8 +5,8 @@ use colored::Colorize;
 use std::fmt;
 use std::fs::File;
 use std::io::BufWriter;
-use tracing::log::LevelFilter;
 use tracing::{Event, Subscriber};
+use tracing_subscriber::filter::LevelFilter;
 use tracing_subscriber::fmt::format::Writer;
 use tracing_subscriber::fmt::{FmtContext, FormatEvent, FormatFields};
 use tracing_subscriber::registry::LookupSpan;
@@ -60,10 +60,10 @@ pub(crate) enum VerbosityLevel {
 impl VerbosityLevel {
    const fn level_filter(self) -> LevelFilter {
        match self {
-            VerbosityLevel::Default => LevelFilter::Warn,
-            VerbosityLevel::Verbose => LevelFilter::Info,
-            VerbosityLevel::ExtraVerbose => LevelFilter::Debug,
-            VerbosityLevel::Trace => LevelFilter::Trace,
+            VerbosityLevel::Default => LevelFilter::WARN,
+            VerbosityLevel::Verbose => LevelFilter::INFO,
+            VerbosityLevel::ExtraVerbose => LevelFilter::DEBUG,
+            VerbosityLevel::Trace => LevelFilter::TRACE,
        }
    }

@@ -88,7 +88,7 @@ pub(crate) fn setup_tracing(level: VerbosityLevel) -> anyhow::Result<TracingGuar
        match level {
            VerbosityLevel::Default => {
                // Show warning traces
-                EnvFilter::default().add_directive(tracing::level_filters::LevelFilter::WARN.into())
+                EnvFilter::default().add_directive(LevelFilter::WARN.into())
            }
            level => {
                let level_filter = level.level_filter();
--- a/crates/red_knot/src/main.rs
+++ b/crates/red_knot/src/main.rs
@@ -7,12 +7,12 @@ use colored::Colorize;
 use crossbeam::channel as crossbeam_channel;
 use salsa::plumbing::ZalsaDatabase;

-use red_knot_python_semantic::{ProgramSettings, SearchPathSettings};
+use red_knot_python_semantic::SitePackages;
 use red_knot_server::run_server;
 use red_knot_workspace::db::RootDatabase;
-use red_knot_workspace::site_packages::VirtualEnvironment;
 use red_knot_workspace::watch;
 use red_knot_workspace::watch::WorkspaceWatcher;
+use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::system::{OsSystem, System, SystemPath, SystemPathBuf};
 use target_version::TargetVersion;
@@ -65,15 +65,14 @@ to resolve type information for the project's third-party dependencies.",
        value_name = "PATH",
        help = "Additional path to use as a module-resolution source (can be passed multiple times)"
    )]
-    extra_search_path: Vec<SystemPathBuf>,
+    extra_search_path: Option<Vec<SystemPathBuf>>,

    #[arg(
        long,
        help = "Python version to assume when resolving types",
-        default_value_t = TargetVersion::default(),
-        value_name="VERSION")
-    ]
-    target_version: TargetVersion,
+        value_name = "VERSION"
+    )]
+    target_version: Option<TargetVersion>,

    #[clap(flatten)]
    verbosity: Verbosity,
@@ -86,6 +85,36 @@ to resolve type information for the project's third-party dependencies.",
    watch: bool,
 }

+impl Args {
+    fn to_configuration(&self, cli_cwd: &SystemPath) -> Configuration {
+        let mut configuration = Configuration::default();
+
+        if let Some(target_version) = self.target_version {
+            configuration.target_version = Some(target_version.into());
+        }
+
+        if let Some(venv_path) = &self.venv_path {
+            configuration.search_paths.site_packages = Some(SitePackages::Derived {
+                venv_path: SystemPath::absolute(venv_path, cli_cwd),
+            });
+        }
+
+        if let Some(custom_typeshed_dir) = &self.custom_typeshed_dir {
+            configuration.search_paths.custom_typeshed =
+                Some(SystemPath::absolute(custom_typeshed_dir, cli_cwd));
+        }
+
+        if let Some(extra_search_paths) = &self.extra_search_path {
+            configuration.search_paths.extra_paths = extra_search_paths
+                .iter()
+                .map(|path| Some(SystemPath::absolute(path, cli_cwd)))
+                .collect();
+        }
+
+        configuration
+    }
+}
+
 #[derive(Debug, clap::Subcommand)]
 pub enum Command {
    /// Start the language server
@@ -115,22 +144,13 @@ pub fn main() -> ExitStatus {
 }

 fn run() -> anyhow::Result<ExitStatus> {
-    let Args {
-        command,
-        current_directory,
-        custom_typeshed_dir,
-        extra_search_path: extra_paths,
-        venv_path,
-        target_version,
-        verbosity,
-        watch,
-    } = Args::parse_from(std::env::args().collect::<Vec<_>>());
+    let args = Args::parse_from(std::env::args().collect::<Vec<_>>());

-    if matches!(command, Some(Command::Server)) {
+    if matches!(args.command, Some(Command::Server)) {
        return run_server().map(|()| ExitStatus::Success);
    }

-    let verbosity = verbosity.level();
+    let verbosity = args.verbosity.level();
    countme::enable(verbosity.is_trace());
    let _guard = setup_tracing(verbosity)?;

@@ -146,10 +166,12 @@ fn run() -> anyhow::Result<ExitStatus> {
            })?
    };

-    let cwd = current_directory
+    let cwd = args
+        .current_directory
+        .as_ref()
        .map(|cwd| {
            if cwd.as_std_path().is_dir() {
-                Ok(SystemPath::absolute(&cwd, &cli_base_path))
+                Ok(SystemPath::absolute(cwd, &cli_base_path))
            } else {
                Err(anyhow!(
                    "Provided current-directory path '{cwd}' is not a directory."
@@ -160,33 +182,18 @@ fn run() -> anyhow::Result<ExitStatus> {
        .unwrap_or_else(|| cli_base_path.clone());

    let system = OsSystem::new(cwd.clone());
-    let workspace_metadata = WorkspaceMetadata::from_path(system.current_directory(), &system)?;
-
-    // TODO: Verify the remaining search path settings eagerly.
-    let site_packages = venv_path
-        .map(|path| {
-            VirtualEnvironment::new(path, &OsSystem::new(cli_base_path))
-                .and_then(|venv| venv.site_packages_directories(&system))
-        })
-        .transpose()?
-        .unwrap_or_default();
-
-    // TODO: Respect the settings from the workspace metadata. when resolving the program settings.
-    let program_settings = ProgramSettings {
-        target_version: target_version.into(),
-        search_paths: SearchPathSettings {
-            extra_paths,
-            src_root: workspace_metadata.root().to_path_buf(),
-            custom_typeshed: custom_typeshed_dir,
-            site_packages,
-        },
-    };
+    let cli_configuration = args.to_configuration(&cwd);
+    let workspace_metadata = WorkspaceMetadata::from_path(
+        system.current_directory(),
+        &system,
+        Some(cli_configuration.clone()),
+    )?;

    // TODO: Use the `program_settings` to compute the key for the database's persistent
    //   cache and load the cache if it exists.
-    let mut db = RootDatabase::new(workspace_metadata, program_settings, system)?;
+    let mut db = RootDatabase::new(workspace_metadata, system)?;

-    let (main_loop, main_loop_cancellation_token) = MainLoop::new();
+    let (main_loop, main_loop_cancellation_token) = MainLoop::new(cli_configuration);

    // Listen to Ctrl+C and abort the watch mode.
    let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
@@ -198,7 +205,7 @@ fn run() -> anyhow::Result<ExitStatus> {
        }
    })?;

-    let exit_status = if watch {
+    let exit_status = if args.watch {
        main_loop.watch(&mut db)?
    } else {
        main_loop.run(&mut db)
@@ -238,10 +245,12 @@ struct MainLoop {

    /// The file system watcher, if running in watch mode.
    watcher: Option<WorkspaceWatcher>,
+
+    cli_configuration: Configuration,
 }

 impl MainLoop {
-    fn new() -> (Self, MainLoopCancellationToken) {
+    fn new(cli_configuration: Configuration) -> (Self, MainLoopCancellationToken) {
        let (sender, receiver) = crossbeam_channel::bounded(10);

        (
@@ -249,6 +258,7 @@ impl MainLoop {
                sender: sender.clone(),
                receiver,
                watcher: None,
+                cli_configuration,
            },
            MainLoopCancellationToken { sender },
        )
@@ -331,7 +341,7 @@ impl MainLoop {
                MainLoopMessage::ApplyChanges(changes) => {
                    revision += 1;
                    // Automatically cancels any pending queries and waits for them to complete.
-                    db.apply_changes(changes);
+                    db.apply_changes(changes, Some(&self.cli_configuration));
                    if let Some(watcher) = self.watcher.as_mut() {
                        watcher.update(db);
                    }
--- a/crates/red_knot/tests/file_watching.rs
+++ b/crates/red_knot/tests/file_watching.rs
@@ -5,12 +5,11 @@ use std::time::Duration;

 use anyhow::{anyhow, Context};

-use red_knot_python_semantic::{
-    resolve_module, ModuleName, Program, ProgramSettings, PythonVersion, SearchPathSettings,
-};
+use red_knot_python_semantic::{resolve_module, ModuleName, Program, PythonVersion, SitePackages};
 use red_knot_workspace::db::RootDatabase;
 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;
@@ -25,7 +24,7 @@ struct TestCase {
    /// We need to hold on to it in the test case or the temp files get deleted.
    _temp_dir: tempfile::TempDir,
    root_dir: SystemPathBuf,
-    search_path_settings: SearchPathSettings,
+    configuration: Configuration,
 }

 impl TestCase {
@@ -41,10 +40,6 @@ impl TestCase {
        &self.db
    }

-    fn db_mut(&mut self) -> &mut RootDatabase {
-        &mut self.db
-    }
-
    fn stop_watch(&mut self) -> Vec<watch::ChangeEvent> {
        self.try_stop_watch(Duration::from_secs(10))
            .expect("Expected watch changes but observed none.")
@@ -105,16 +100,20 @@ impl TestCase {
        Some(all_events)
    }

+    fn apply_changes(&mut self, changes: Vec<watch::ChangeEvent>) {
+        self.db.apply_changes(changes, Some(&self.configuration));
+    }
+
    fn update_search_path_settings(
        &mut self,
-        f: impl FnOnce(&SearchPathSettings) -> SearchPathSettings,
+        configuration: SearchPathConfiguration,
    ) -> anyhow::Result<()> {
        let program = Program::get(self.db());

-        let new_settings = f(&self.search_path_settings);
+        self.configuration.search_paths = configuration.clone();
+        let new_settings = configuration.into_settings(self.db.workspace().root(&self.db));

-        program.update_search_paths(&mut self.db, new_settings.clone())?;
-        self.search_path_settings = new_settings;
+        program.update_search_paths(&mut self.db, &new_settings)?;

        if let Some(watcher) = &mut self.watcher {
            watcher.update(&self.db);
@@ -127,7 +126,6 @@ impl TestCase {
    fn collect_package_files(&self, path: &SystemPath) -> Vec<File> {
        let package = self.db().workspace().package(self.db(), path).unwrap();
        let files = package.files(self.db());
-        let files = files.read();
        let mut collected: Vec<_> = files.into_iter().collect();
        collected.sort_unstable_by_key(|file| file.path(self.db()).as_system_path().unwrap());
        collected
@@ -180,17 +178,14 @@ fn setup<F>(setup_files: F) -> anyhow::Result<TestCase>
 where
    F: SetupFiles,
 {
-    setup_with_search_paths(setup_files, |_root, workspace_path| SearchPathSettings {
-        extra_paths: vec![],
-        src_root: workspace_path.to_path_buf(),
-        custom_typeshed: None,
-        site_packages: vec![],
+    setup_with_search_paths(setup_files, |_root, _workspace_path| {
+        SearchPathConfiguration::default()
    })
 }

 fn setup_with_search_paths<F>(
    setup_files: F,
-    create_search_paths: impl FnOnce(&SystemPath, &SystemPath) -> SearchPathSettings,
+    create_search_paths: impl FnOnce(&SystemPath, &SystemPath) -> SearchPathConfiguration,
 ) -> anyhow::Result<TestCase>
 where
    F: SetupFiles,
@@ -222,25 +217,34 @@ where

    let system = OsSystem::new(&workspace_path);

-    let workspace = WorkspaceMetadata::from_path(&workspace_path, &system)?;
-    let search_path_settings = create_search_paths(&root_path, workspace.root());
+    let search_paths = create_search_paths(&root_path, &workspace_path);

-    for path in search_path_settings
+    for path in search_paths
        .extra_paths
        .iter()
-        .chain(search_path_settings.site_packages.iter())
-        .chain(search_path_settings.custom_typeshed.iter())
+        .flatten()
+        .chain(search_paths.custom_typeshed.iter())
+        .chain(search_paths.site_packages.iter().flat_map(|site_packages| {
+            if let SitePackages::Known(path) = site_packages {
+                path.as_slice()
+            } else {
+                &[]
+            }
+        }))
    {
        std::fs::create_dir_all(path.as_std_path())
            .with_context(|| format!("Failed to create search path '{path}'"))?;
    }

-    let settings = ProgramSettings {
-        target_version: PythonVersion::default(),
-        search_paths: search_path_settings.clone(),
+    let configuration = Configuration {
+        target_version: Some(PythonVersion::PY312),
+        search_paths,
    };

-    let db = RootDatabase::new(workspace, settings, system)?;
+    let workspace =
+        WorkspaceMetadata::from_path(&workspace_path, &system, Some(configuration.clone()))?;
+
+    let db = RootDatabase::new(workspace, system)?;

    let (sender, receiver) = crossbeam::channel::unbounded();
    let watcher = directory_watcher(move |events| sender.send(events).unwrap())
@@ -255,7 +259,7 @@ where
        watcher: Some(watcher),
        _temp_dir: temp_dir,
        root_dir: root_path,
-        search_path_settings,
+        configuration,
    };

    // Sometimes the file watcher reports changes for events that happened before the watcher was started.
@@ -308,7 +312,7 @@ fn new_file() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    let foo = case.system_file(&foo_path).expect("foo.py to exist.");

@@ -331,7 +335,7 @@ fn new_ignored_file() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(case.system_file(&foo_path).is_ok());
    assert_eq!(&case.collect_package_files(&bar_path), &[bar_file]);
@@ -355,7 +359,7 @@ fn changed_file() -> anyhow::Result<()> {

    assert!(!changes.is_empty());

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert_eq!(source_text(case.db(), foo).as_str(), "print('Version 2')");
    assert_eq!(&case.collect_package_files(&foo_path), &[foo]);
@@ -378,7 +382,7 @@ fn deleted_file() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(!foo.exists(case.db()));
    assert_eq!(&case.collect_package_files(&foo_path), &[] as &[File]);
@@ -410,7 +414,7 @@ fn move_file_to_trash() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(!foo.exists(case.db()));
    assert_eq!(&case.collect_package_files(&foo_path), &[] as &[File]);
@@ -442,7 +446,7 @@ fn move_file_to_workspace() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    let foo_in_workspace = case.system_file(&foo_in_workspace_path)?;

@@ -470,7 +474,7 @@ fn rename_file() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(!foo.exists(case.db()));

@@ -511,7 +515,7 @@ fn directory_moved_to_workspace() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    let init_file = case
        .system_file(sub_new_path.join("__init__.py"))
@@ -562,7 +566,7 @@ fn directory_moved_to_trash() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    // `import sub.a` should no longer resolve
    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("sub.a").unwrap()).is_none());
@@ -616,7 +620,7 @@ fn directory_renamed() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    // `import sub.a` should no longer resolve
    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("sub.a").unwrap()).is_none());
@@ -681,7 +685,7 @@ fn directory_deleted() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    // `import sub.a` should no longer resolve
    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("sub.a").unwrap()).is_none());
@@ -695,15 +699,13 @@ fn directory_deleted() -> anyhow::Result<()> {

 #[test]
 fn search_path() -> anyhow::Result<()> {
-    let mut case =
-        setup_with_search_paths([("bar.py", "import sub.a")], |root_path, workspace_path| {
-            SearchPathSettings {
-                extra_paths: vec![],
-                src_root: workspace_path.to_path_buf(),
-                custom_typeshed: None,
-                site_packages: vec![root_path.join("site_packages")],
-            }
-        })?;
+    let mut case = setup_with_search_paths(
+        [("bar.py", "import sub.a")],
+        |root_path, _workspace_path| SearchPathConfiguration {
+            site_packages: Some(SitePackages::Known(vec![root_path.join("site_packages")])),
+            ..SearchPathConfiguration::default()
+        },
+    )?;

    let site_packages = case.root_path().join("site_packages");

@@ -716,7 +718,7 @@ fn search_path() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("a").unwrap()).is_some());
    assert_eq!(
@@ -737,9 +739,9 @@ fn add_search_path() -> anyhow::Result<()> {
    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("a").unwrap()).is_none());

    // Register site-packages as a search path.
-    case.update_search_path_settings(|settings| SearchPathSettings {
-        site_packages: vec![site_packages.clone()],
-        ..settings.clone()
+    case.update_search_path_settings(SearchPathConfiguration {
+        site_packages: Some(SitePackages::Known(vec![site_packages.clone()])),
+        ..SearchPathConfiguration::default()
    })
    .expect("Search path settings to be valid");

@@ -747,7 +749,7 @@ fn add_search_path() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert!(resolve_module(case.db().upcast(), ModuleName::new_static("a").unwrap()).is_some());

@@ -756,21 +758,19 @@ fn add_search_path() -> anyhow::Result<()> {

 #[test]
 fn remove_search_path() -> anyhow::Result<()> {
-    let mut case =
-        setup_with_search_paths([("bar.py", "import sub.a")], |root_path, workspace_path| {
-            SearchPathSettings {
-                extra_paths: vec![],
-                src_root: workspace_path.to_path_buf(),
-                custom_typeshed: None,
-                site_packages: vec![root_path.join("site_packages")],
-            }
-        })?;
+    let mut case = setup_with_search_paths(
+        [("bar.py", "import sub.a")],
+        |root_path, _workspace_path| SearchPathConfiguration {
+            site_packages: Some(SitePackages::Known(vec![root_path.join("site_packages")])),
+            ..SearchPathConfiguration::default()
+        },
+    )?;

    // Remove site packages from the search path settings.
    let site_packages = case.root_path().join("site_packages");
-    case.update_search_path_settings(|settings| SearchPathSettings {
-        site_packages: vec![],
-        ..settings.clone()
+    case.update_search_path_settings(SearchPathConfiguration {
+        site_packages: None,
+        ..SearchPathConfiguration::default()
    })
    .expect("Search path settings to be valid");

@@ -783,6 +783,48 @@ fn remove_search_path() -> anyhow::Result<()> {
    Ok(())
 }

+#[test]
+fn changed_versions_file() -> anyhow::Result<()> {
+    let mut case = setup_with_search_paths(
+        |root_path: &SystemPath, workspace_path: &SystemPath| {
+            std::fs::write(workspace_path.join("bar.py").as_std_path(), "import sub.a")?;
+            std::fs::create_dir_all(root_path.join("typeshed/stdlib").as_std_path())?;
+            std::fs::write(root_path.join("typeshed/stdlib/VERSIONS").as_std_path(), "")?;
+            std::fs::write(
+                root_path.join("typeshed/stdlib/os.pyi").as_std_path(),
+                "# not important",
+            )?;
+
+            Ok(())
+        },
+        |root_path, _workspace_path| SearchPathConfiguration {
+            custom_typeshed: Some(root_path.join("typeshed")),
+            ..SearchPathConfiguration::default()
+        },
+    )?;
+
+    // Unset the custom typeshed directory.
+    assert_eq!(
+        resolve_module(case.db(), ModuleName::new("os").unwrap()),
+        None
+    );
+
+    std::fs::write(
+        case.root_path()
+            .join("typeshed/stdlib/VERSIONS")
+            .as_std_path(),
+        "os: 3.0-",
+    )?;
+
+    let changes = case.stop_watch();
+
+    case.apply_changes(changes);
+
+    assert!(resolve_module(case.db(), ModuleName::new("os").unwrap()).is_some());
+
+    Ok(())
+}
+
 /// Watch a workspace that contains two files where one file is a hardlink to another.
 ///
 /// Setup:
@@ -829,7 +871,7 @@ fn hard_links_in_workspace() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert_eq!(source_text(case.db(), foo).as_str(), "print('Version 2')");

@@ -900,7 +942,7 @@ fn hard_links_to_target_outside_workspace() -> anyhow::Result<()> {

    let changes = case.stop_watch();

-    case.db_mut().apply_changes(changes);
+    case.apply_changes(changes);

    assert_eq!(source_text(case.db(), bar).as_str(), "print('Version 2')");

@@ -939,7 +981,7 @@ mod unix {

        let changes = case.stop_watch();

-        case.db_mut().apply_changes(changes);
+        case.apply_changes(changes);

        assert_eq!(
            foo.permissions(case.db()),
@@ -1024,7 +1066,7 @@ mod unix {

        let changes = case.take_watch_changes();

-        case.db_mut().apply_changes(changes);
+        case.apply_changes(changes);

        assert_eq!(
            source_text(case.db(), baz.file()).as_str(),
@@ -1037,7 +1079,7 @@ mod unix {

        let changes = case.stop_watch();

-        case.db_mut().apply_changes(changes);
+        case.apply_changes(changes);

        assert_eq!(
            source_text(case.db(), baz.file()).as_str(),
@@ -1108,7 +1150,7 @@ mod unix {

        let changes = case.stop_watch();

-        case.db_mut().apply_changes(changes);
+        case.apply_changes(changes);

        // The file watcher is guaranteed to emit one event for the changed file, but it isn't specified
        // if the event is emitted for the "original" or linked path because both paths are watched.
@@ -1177,11 +1219,11 @@ mod unix {

                Ok(())
            },
-            |_root, workspace| SearchPathSettings {
-                extra_paths: vec![],
-                src_root: workspace.to_path_buf(),
-                custom_typeshed: None,
-                site_packages: vec![workspace.join(".venv/lib/python3.12/site-packages")],
+            |_root, workspace| SearchPathConfiguration {
+                site_packages: Some(SitePackages::Known(vec![
+                    workspace.join(".venv/lib/python3.12/site-packages")
+                ])),
+                ..SearchPathConfiguration::default()
            },
        )?;

@@ -1216,7 +1258,7 @@ mod unix {

        let changes = case.stop_watch();

-        case.db_mut().apply_changes(changes);
+        case.apply_changes(changes);

        assert_eq!(
            source_text(case.db(), baz_original_file).as_str(),
--- a/crates/red_knot_python_semantic/Cargo.toml
+++ b/crates/red_knot_python_semantic/Cargo.toml
@@ -17,6 +17,7 @@ ruff_python_ast = { workspace = true }
 ruff_python_stdlib = { workspace = true }
 ruff_source_file = { workspace = true }
 ruff_text_size = { workspace = true }
+ruff_python_literal = { workspace = true }

 anyhow = { workspace = true }
 bitflags = { workspace = true }
@@ -26,6 +27,7 @@ countme = { workspace = true }
 once_cell = { workspace = true }
 ordermap = { workspace = true }
 salsa = { workspace = true }
+thiserror = { workspace = true }
 tracing = { workspace = true }
 rustc-hash = { workspace = true }
 hashbrown = { workspace = true }
--- a/crates/red_knot_python_semantic/src/db.rs
+++ b/crates/red_knot_python_semantic/src/db.rs
@@ -1,15 +1,18 @@
+use ruff_db::files::File;
 use ruff_db::{Db as SourceDb, Upcast};

 /// Database giving access to semantic information about a Python program.
 #[salsa::db]
-pub trait Db: SourceDb + Upcast<dyn SourceDb> {}
+pub trait Db: SourceDb + Upcast<dyn SourceDb> {
+    fn is_file_open(&self, file: File) -> bool;
+}

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

    use crate::module_resolver::vendored_typeshed_stubs;
-    use ruff_db::files::Files;
+    use ruff_db::files::{File, Files};
    use ruff_db::system::{DbWithTestSystem, System, TestSystem};
    use ruff_db::vendored::VendoredFileSystem;
    use ruff_db::{Db as SourceDb, Upcast};
@@ -91,7 +94,11 @@ pub(crate) mod tests {
    }

    #[salsa::db]
-    impl Db for TestDb {}
+    impl Db for TestDb {
+        fn is_file_open(&self, file: File) -> bool {
+            !file.path(self).is_vendored_path()
+        }
+    }

    #[salsa::db]
    impl salsa::Database for TestDb {
--- a/crates/red_knot_python_semantic/src/lib.rs
+++ b/crates/red_knot_python_semantic/src/lib.rs
@@ -5,7 +5,7 @@ use rustc_hash::FxHasher;
 pub use db::Db;
 pub use module_name::ModuleName;
 pub use module_resolver::{resolve_module, system_module_search_paths, vendored_typeshed_stubs};
-pub use program::{Program, ProgramSettings, SearchPathSettings};
+pub use program::{Program, ProgramSettings, SearchPathSettings, SitePackages};
 pub use python_version::PythonVersion;
 pub use semantic_model::{HasTy, SemanticModel};

@@ -19,6 +19,7 @@ mod program;
 mod python_version;
 pub mod semantic_index;
 mod semantic_model;
+pub(crate) mod site_packages;
 pub mod types;

 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;
--- a/crates/red_knot_python_semantic/src/module_resolver/mod.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/mod.rs
@@ -13,7 +13,6 @@ use resolver::SearchPathIterator;
 mod module;
 mod path;
 mod resolver;
-mod state;
 mod typeshed;

 #[cfg(test)]
--- a/crates/red_knot_python_semantic/src/module_resolver/path.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/path.rs
@@ -9,11 +9,11 @@ use ruff_db::files::{system_path_to_file, vendored_path_to_file, File, FileError
 use ruff_db::system::{System, SystemPath, SystemPathBuf};
 use ruff_db::vendored::{VendoredPath, VendoredPathBuf};

+use super::typeshed::{typeshed_versions, TypeshedVersionsParseError, TypeshedVersionsQueryResult};
 use crate::db::Db;
 use crate::module_name::ModuleName;
-
-use super::state::ResolverState;
-use super::typeshed::{TypeshedVersionsParseError, TypeshedVersionsQueryResult};
+use crate::module_resolver::resolver::ResolverContext;
+use crate::site_packages::SitePackagesDiscoveryError;

 /// A path that points to a Python module.
 ///
@@ -60,7 +60,7 @@ impl ModulePath {
    }

    #[must_use]
-    pub(crate) fn is_directory(&self, resolver: &ResolverState) -> bool {
+    pub(super) fn is_directory(&self, resolver: &ResolverContext) -> bool {
        let ModulePath {
            search_path,
            relative_path,
@@ -74,7 +74,7 @@ impl ModulePath {
                    == Err(FileError::IsADirectory)
            }
            SearchPathInner::StandardLibraryCustom(stdlib_root) => {
-                match query_stdlib_version(Some(stdlib_root), relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => false,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => {
@@ -84,7 +84,7 @@ impl ModulePath {
                }
            }
            SearchPathInner::StandardLibraryVendored(stdlib_root) => {
-                match query_stdlib_version(None, relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => false,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => resolver
@@ -96,7 +96,7 @@ impl ModulePath {
    }

    #[must_use]
-    pub(crate) fn is_regular_package(&self, resolver: &ResolverState) -> bool {
+    pub(super) fn is_regular_package(&self, resolver: &ResolverContext) -> bool {
        let ModulePath {
            search_path,
            relative_path,
@@ -113,7 +113,7 @@ impl ModulePath {
                        .is_ok()
            }
            SearchPathInner::StandardLibraryCustom(search_path) => {
-                match query_stdlib_version(Some(search_path), relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => false,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => system_path_to_file(
@@ -124,7 +124,7 @@ impl ModulePath {
                }
            }
            SearchPathInner::StandardLibraryVendored(search_path) => {
-                match query_stdlib_version(None, relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => false,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => resolver
@@ -136,7 +136,7 @@ impl ModulePath {
    }

    #[must_use]
-    pub(crate) fn to_file(&self, resolver: &ResolverState) -> Option<File> {
+    pub(super) fn to_file(&self, resolver: &ResolverContext) -> Option<File> {
        let db = resolver.db.upcast();
        let ModulePath {
            search_path,
@@ -150,7 +150,7 @@ impl ModulePath {
                system_path_to_file(db, search_path.join(relative_path)).ok()
            }
            SearchPathInner::StandardLibraryCustom(stdlib_root) => {
-                match query_stdlib_version(Some(stdlib_root), relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => None,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => {
@@ -159,7 +159,7 @@ impl ModulePath {
                }
            }
            SearchPathInner::StandardLibraryVendored(stdlib_root) => {
-                match query_stdlib_version(None, relative_path, resolver) {
+                match query_stdlib_version(relative_path, resolver) {
                    TypeshedVersionsQueryResult::DoesNotExist => None,
                    TypeshedVersionsQueryResult::Exists
                    | TypeshedVersionsQueryResult::MaybeExists => {
@@ -273,19 +273,15 @@ fn stdlib_path_to_module_name(relative_path: &Utf8Path) -> Option<ModuleName> {

 #[must_use]
 fn query_stdlib_version(
-    custom_stdlib_root: Option<&SystemPath>,
    relative_path: &Utf8Path,
-    resolver: &ResolverState,
+    context: &ResolverContext,
 ) -> TypeshedVersionsQueryResult {
    let Some(module_name) = stdlib_path_to_module_name(relative_path) else {
        return TypeshedVersionsQueryResult::DoesNotExist;
    };
-    let ResolverState {
-        db,
-        typeshed_versions,
-        target_version,
-    } = resolver;
-    typeshed_versions.query_module(*db, &module_name, custom_stdlib_root, *target_version)
+    let ResolverContext { db, target_version } = context;
+
+    typeshed_versions(*db).query_module(&module_name, *target_version)
 }

 /// Enumeration describing the various ways in which validation of a search path might fail.
@@ -293,7 +289,7 @@ fn query_stdlib_version(
 /// If validation fails for a search path derived from the user settings,
 /// a message must be displayed to the user,
 /// as type checking cannot be done reliably in these circumstances.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug)]
 pub(crate) enum SearchPathValidationError {
    /// The path provided by the user was not a directory
    NotADirectory(SystemPathBuf),
@@ -304,18 +300,20 @@ pub(crate) enum SearchPathValidationError {
    NoStdlibSubdirectory(SystemPathBuf),

    /// The typeshed path provided by the user is a directory,
-    /// but no `stdlib/VERSIONS` file exists.
+    /// but `stdlib/VERSIONS` could not be read.
    /// (This is only relevant for stdlib search paths.)
-    NoVersionsFile(SystemPathBuf),
-
-    /// `stdlib/VERSIONS` is a directory.
-    /// (This is only relevant for stdlib search paths.)
-    VersionsIsADirectory(SystemPathBuf),
+    FailedToReadVersionsFile {
+        path: SystemPathBuf,
+        error: std::io::Error,
+    },

    /// The path provided by the user is a directory,
    /// and a `stdlib/VERSIONS` file exists, but it fails to parse.
    /// (This is only relevant for stdlib search paths.)
    VersionsParseError(TypeshedVersionsParseError),
+
+    /// Failed to discover the site-packages for the configured virtual environment.
+    SitePackagesDiscovery(SitePackagesDiscoveryError),
 }

 impl fmt::Display for SearchPathValidationError {
@@ -325,9 +323,16 @@ impl fmt::Display for SearchPathValidationError {
            Self::NoStdlibSubdirectory(path) => {
                write!(f, "The directory at {path} has no `stdlib/` subdirectory")
            }
-            Self::NoVersionsFile(path) => write!(f, "Expected a file at {path}/stdlib/VERSIONS"),
-            Self::VersionsIsADirectory(path) => write!(f, "{path}/stdlib/VERSIONS is a directory."),
+            Self::FailedToReadVersionsFile { path, error } => {
+                write!(
+                    f,
+                    "Failed to read the custom typeshed versions file '{path}': {error}"
+                )
+            }
            Self::VersionsParseError(underlying_error) => underlying_error.fmt(f),
+            SearchPathValidationError::SitePackagesDiscovery(error) => {
+                write!(f, "Failed to discover the site-packages directory: {error}")
+            }
        }
    }
 }
@@ -342,6 +347,18 @@ impl std::error::Error for SearchPathValidationError {
    }
 }

+impl From<TypeshedVersionsParseError> for SearchPathValidationError {
+    fn from(value: TypeshedVersionsParseError) -> Self {
+        Self::VersionsParseError(value)
+    }
+}
+
+impl From<SitePackagesDiscoveryError> for SearchPathValidationError {
+    fn from(value: SitePackagesDiscoveryError) -> Self {
+        Self::SitePackagesDiscovery(value)
+    }
+}
+
 type SearchPathResult<T> = Result<T, SearchPathValidationError>;

 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -384,11 +401,10 @@ pub(crate) struct SearchPath(Arc<SearchPathInner>);

 impl SearchPath {
    fn directory_path(system: &dyn System, root: SystemPathBuf) -> SearchPathResult<SystemPathBuf> {
-        let canonicalized = system.canonicalize_path(&root).unwrap_or(root);
-        if system.is_directory(&canonicalized) {
-            Ok(canonicalized)
+        if system.is_directory(&root) {
+            Ok(root)
        } else {
-            Err(SearchPathValidationError::NotADirectory(canonicalized))
+            Err(SearchPathValidationError::NotADirectory(root))
        }
    }

@@ -407,32 +423,22 @@ impl SearchPath {
    }

    /// Create a new standard-library search path pointing to a custom directory on disk
-    pub(crate) fn custom_stdlib(db: &dyn Db, typeshed: SystemPathBuf) -> SearchPathResult<Self> {
+    pub(crate) fn custom_stdlib(db: &dyn Db, typeshed: &SystemPath) -> SearchPathResult<Self> {
        let system = db.system();
-        if !system.is_directory(&typeshed) {
+        if !system.is_directory(typeshed) {
            return Err(SearchPathValidationError::NotADirectory(
                typeshed.to_path_buf(),
            ));
        }
+
        let stdlib =
            Self::directory_path(system, typeshed.join("stdlib")).map_err(|err| match err {
-                SearchPathValidationError::NotADirectory(path) => {
-                    SearchPathValidationError::NoStdlibSubdirectory(path)
+                SearchPathValidationError::NotADirectory(_) => {
+                    SearchPathValidationError::NoStdlibSubdirectory(typeshed.to_path_buf())
                }
                err => err,
            })?;
-        let typeshed_versions =
-            system_path_to_file(db.upcast(), stdlib.join("VERSIONS")).map_err(|err| match err {
-                FileError::NotFound => SearchPathValidationError::NoVersionsFile(typeshed),
-                FileError::IsADirectory => {
-                    SearchPathValidationError::VersionsIsADirectory(typeshed)
-                }
-            })?;
-        super::typeshed::parse_typeshed_versions(db, typeshed_versions)
-            .as_ref()
-            .map_err(|validation_error| {
-                SearchPathValidationError::VersionsParseError(validation_error.clone())
-            })?;
+
        Ok(Self(Arc::new(SearchPathInner::StandardLibraryCustom(
            stdlib,
        ))))
@@ -623,11 +629,11 @@ mod tests {
    use ruff_db::Db;

    use crate::db::tests::TestDb;
-
-    use super::*;
    use crate::module_resolver::testing::{FileSpec, MockedTypeshed, TestCase, TestCaseBuilder};
    use crate::python_version::PythonVersion;

+    use super::*;
+
    impl ModulePath {
        #[must_use]
        fn join(&self, component: &str) -> ModulePath {
@@ -638,15 +644,6 @@ mod tests {
    }

    impl SearchPath {
-        #[must_use]
-        pub(crate) fn is_stdlib_search_path(&self) -> bool {
-            matches!(
-                &*self.0,
-                SearchPathInner::StandardLibraryCustom(_)
-                    | SearchPathInner::StandardLibraryVendored(_)
-            )
-        }
-
        fn join(&self, component: &str) -> ModulePath {
            self.to_module_path().join(component)
        }
@@ -661,7 +658,7 @@ mod tests {
            .build();

        assert_eq!(
-            SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf())
+            SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
                .unwrap()
                .to_module_path()
                .with_py_extension(),
@@ -669,7 +666,7 @@ mod tests {
        );

        assert_eq!(
-            &SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf())
+            &SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
                .unwrap()
                .join("foo")
                .with_pyi_extension(),
@@ -780,7 +777,7 @@ mod tests {
        let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
            .with_custom_typeshed(MockedTypeshed::default())
            .build();
-        SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf())
+        SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
            .unwrap()
            .to_module_path()
            .push("bar.py");
@@ -792,7 +789,7 @@ mod tests {
        let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
            .with_custom_typeshed(MockedTypeshed::default())
            .build();
-        SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf())
+        SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
            .unwrap()
            .to_module_path()
            .push("bar.rs");
@@ -824,7 +821,7 @@ mod tests {
            .with_custom_typeshed(MockedTypeshed::default())
            .build();

-        let root = SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf()).unwrap();
+        let root = SearchPath::custom_stdlib(&db, stdlib.parent().unwrap()).unwrap();

        // Must have a `.pyi` extension or no extension:
        let bad_absolute_path = SystemPath::new("foo/stdlib/x.py");
@@ -872,8 +869,7 @@ mod tests {
            .with_custom_typeshed(typeshed)
            .with_target_version(target_version)
            .build();
-        let stdlib =
-            SearchPath::custom_stdlib(&db, stdlib.parent().unwrap().to_path_buf()).unwrap();
+        let stdlib = SearchPath::custom_stdlib(&db, stdlib.parent().unwrap()).unwrap();
        (db, stdlib)
    }

@@ -898,7 +894,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let asyncio_regular_package = stdlib_path.join("asyncio");
        assert!(asyncio_regular_package.is_directory(&resolver));
@@ -926,7 +922,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let xml_namespace_package = stdlib_path.join("xml");
        assert!(xml_namespace_package.is_directory(&resolver));
@@ -948,7 +944,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let functools_module = stdlib_path.join("functools.pyi");
        assert!(functools_module.to_file(&resolver).is_some());
@@ -964,7 +960,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let collections_regular_package = stdlib_path.join("collections");
        assert_eq!(collections_regular_package.to_file(&resolver), None);
@@ -980,7 +976,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let importlib_namespace_package = stdlib_path.join("importlib");
        assert_eq!(importlib_namespace_package.to_file(&resolver), None);
@@ -1001,7 +997,7 @@ mod tests {
        };

        let (db, stdlib_path) = py38_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY38);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY38);

        let non_existent = stdlib_path.join("doesnt_even_exist");
        assert_eq!(non_existent.to_file(&resolver), None);
@@ -1029,7 +1025,7 @@ mod tests {
        };

        let (db, stdlib_path) = py39_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY39);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY39);

        // Since we've set the target version to Py39,
        // `collections` should now exist as a directory, according to VERSIONS...
@@ -1058,7 +1054,7 @@ mod tests {
        };

        let (db, stdlib_path) = py39_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY39);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY39);

        // The `importlib` directory now also exists
        let importlib_namespace_package = stdlib_path.join("importlib");
@@ -1082,7 +1078,7 @@ mod tests {
        };

        let (db, stdlib_path) = py39_typeshed_test_case(TYPESHED);
-        let resolver = ResolverState::new(&db, PythonVersion::PY39);
+        let resolver = ResolverContext::new(&db, PythonVersion::PY39);

        // The `xml` package no longer exists on py39:
        let xml_namespace_package = stdlib_path.join("xml");
--- a/crates/red_knot_python_semantic/src/module_resolver/resolver.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/resolver.rs
@@ -1,19 +1,19 @@
+use rustc_hash::{FxBuildHasher, FxHashSet};
 use std::borrow::Cow;
 use std::iter::FusedIterator;
-
-use rustc_hash::{FxBuildHasher, FxHashSet};
+use std::ops::Deref;

 use ruff_db::files::{File, FilePath, FileRootKind};
-use ruff_db::system::{DirectoryEntry, SystemPath, SystemPathBuf};
-use ruff_db::vendored::VendoredPath;
-
-use crate::db::Db;
-use crate::module_name::ModuleName;
-use crate::{Program, SearchPathSettings};
+use ruff_db::system::{DirectoryEntry, System, SystemPath, SystemPathBuf};
+use ruff_db::vendored::{VendoredFileSystem, VendoredPath};

 use super::module::{Module, ModuleKind};
 use super::path::{ModulePath, SearchPath, SearchPathValidationError};
-use super::state::ResolverState;
+use crate::db::Db;
+use crate::module_name::ModuleName;
+use crate::module_resolver::typeshed::{vendored_typeshed_versions, TypeshedVersions};
+use crate::site_packages::VirtualEnvironment;
+use crate::{Program, PythonVersion, SearchPathSettings, SitePackages};

 /// Resolves a module name to a module.
 pub fn resolve_module(db: &dyn Db, module_name: ModuleName) -> Option<Module> {
@@ -41,7 +41,7 @@ pub(crate) fn resolve_module_query<'db>(

    let module = Module::new(name.clone(), kind, search_path, module_file);

-    tracing::debug!(
+    tracing::trace!(
        "Resolved module '{name}' to '{path}'.",
        path = module_file.path(db)
    );
@@ -122,7 +122,7 @@ pub(crate) fn search_paths(db: &dyn Db) -> SearchPathIterator {
    Program::get(db).search_paths(db).iter(db)
 }

-#[derive(Debug, PartialEq, Eq, Default)]
+#[derive(Debug, PartialEq, Eq)]
 pub(crate) struct SearchPaths {
    /// Search paths that have been statically determined purely from reading Ruff's configuration settings.
    /// These shouldn't ever change unless the config settings themselves change.
@@ -135,6 +135,8 @@ pub(crate) struct SearchPaths {
    /// in terms of module-resolution priority until we've discovered the editable installs
    /// for the first `site-packages` path
    site_packages: Vec<SearchPath>,
+
+    typeshed_versions: ResolvedTypeshedVersions,
 }

 impl SearchPaths {
@@ -146,8 +148,14 @@ impl SearchPaths {
    /// [module resolution order]: https://typing.readthedocs.io/en/latest/spec/distributing.html#import-resolution-ordering
    pub(crate) fn from_settings(
        db: &dyn Db,
-        settings: SearchPathSettings,
+        settings: &SearchPathSettings,
    ) -> Result<Self, SearchPathValidationError> {
+        fn canonicalize(path: &SystemPath, system: &dyn System) -> SystemPathBuf {
+            system
+                .canonicalize_path(path)
+                .unwrap_or_else(|_| path.to_path_buf())
+        }
+
        let SearchPathSettings {
            extra_paths,
            src_root,
@@ -161,45 +169,65 @@ impl SearchPaths {
        let mut static_paths = vec![];

        for path in extra_paths {
-            tracing::debug!("Adding static extra search-path '{path}'");
+            let path = canonicalize(path, system);
+            files.try_add_root(db.upcast(), &path, FileRootKind::LibrarySearchPath);
+            tracing::debug!("Adding extra search-path '{path}'");

-            let search_path = SearchPath::extra(system, path)?;
-            files.try_add_root(
-                db.upcast(),
-                search_path.as_system_path().unwrap(),
-                FileRootKind::LibrarySearchPath,
-            );
-            static_paths.push(search_path);
+            static_paths.push(SearchPath::extra(system, path)?);
        }

-        tracing::debug!("Adding static search path '{src_root}'");
-        static_paths.push(SearchPath::first_party(system, src_root)?);
+        tracing::debug!("Adding first-party search path '{src_root}'");
+        static_paths.push(SearchPath::first_party(system, src_root.to_path_buf())?);

-        static_paths.push(if let Some(custom_typeshed) = custom_typeshed {
-            tracing::debug!("Adding static custom-sdtlib search-path '{custom_typeshed}'");
+        let (typeshed_versions, stdlib_path) = if let Some(custom_typeshed) = custom_typeshed {
+            let custom_typeshed = canonicalize(custom_typeshed, system);
+            tracing::debug!("Adding custom-stdlib search path '{custom_typeshed}'");

-            let search_path = SearchPath::custom_stdlib(db, custom_typeshed)?;
            files.try_add_root(
                db.upcast(),
-                search_path.as_system_path().unwrap(),
+                &custom_typeshed,
                FileRootKind::LibrarySearchPath,
            );
-            search_path
+
+            let versions_path = custom_typeshed.join("stdlib/VERSIONS");
+
+            let versions_content = system.read_to_string(&versions_path).map_err(|error| {
+                SearchPathValidationError::FailedToReadVersionsFile {
+                    path: versions_path,
+                    error,
+                }
+            })?;
+
+            let parsed: TypeshedVersions = versions_content.parse()?;
+
+            let search_path = SearchPath::custom_stdlib(db, &custom_typeshed)?;
+
+            (ResolvedTypeshedVersions::Custom(parsed), search_path)
        } else {
-            SearchPath::vendored_stdlib()
-        });
+            tracing::debug!("Using vendored stdlib");
+            (
+                ResolvedTypeshedVersions::Vendored(vendored_typeshed_versions()),
+                SearchPath::vendored_stdlib(),
+            )
+        };
+
+        static_paths.push(stdlib_path);
+
+        let site_packages_paths = match site_packages_paths {
+            SitePackages::Derived { venv_path } => VirtualEnvironment::new(venv_path, system)
+                .and_then(|venv| venv.site_packages_directories(system))?,
+            SitePackages::Known(paths) => paths
+                .iter()
+                .map(|path| canonicalize(path, system))
+                .collect(),
+        };

        let mut site_packages: Vec<_> = Vec::with_capacity(site_packages_paths.len());

        for path in site_packages_paths {
-            tracing::debug!("Adding site-package path '{path}'");
-            let search_path = SearchPath::site_packages(system, path)?;
-            files.try_add_root(
-                db.upcast(),
-                search_path.as_system_path().unwrap(),
-                FileRootKind::LibrarySearchPath,
-            );
-            site_packages.push(search_path);
+            tracing::debug!("Adding site-packages search path '{path}'");
+            files.try_add_root(db.upcast(), &path, FileRootKind::LibrarySearchPath);
+            site_packages.push(SearchPath::site_packages(system, path)?);
        }

        // TODO vendor typeshed's third-party stubs as well as the stdlib and fallback to them as a final step
@@ -224,16 +252,48 @@ impl SearchPaths {
        Ok(SearchPaths {
            static_paths,
            site_packages,
+            typeshed_versions,
        })
    }

-    pub(crate) fn iter<'a>(&'a self, db: &'a dyn Db) -> SearchPathIterator<'a> {
+    pub(super) fn iter<'a>(&'a self, db: &'a dyn Db) -> SearchPathIterator<'a> {
        SearchPathIterator {
            db,
            static_paths: self.static_paths.iter(),
            dynamic_paths: None,
        }
    }
+
+    pub(crate) fn custom_stdlib(&self) -> Option<&SystemPath> {
+        self.static_paths.iter().find_map(|search_path| {
+            if search_path.is_standard_library() {
+                search_path.as_system_path()
+            } else {
+                None
+            }
+        })
+    }
+
+    pub(super) fn typeshed_versions(&self) -> &TypeshedVersions {
+        &self.typeshed_versions
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum ResolvedTypeshedVersions {
+    Vendored(&'static TypeshedVersions),
+    Custom(TypeshedVersions),
+}
+
+impl Deref for ResolvedTypeshedVersions {
+    type Target = TypeshedVersions;
+
+    fn deref(&self) -> &Self::Target {
+        match self {
+            ResolvedTypeshedVersions::Vendored(versions) => versions,
+            ResolvedTypeshedVersions::Custom(versions) => versions,
+        }
+    }
 }

 /// Collect all dynamic search paths. For each `site-packages` path:
@@ -251,6 +311,7 @@ pub(crate) fn dynamic_resolution_paths(db: &dyn Db) -> Vec<SearchPath> {
    let SearchPaths {
        static_paths,
        site_packages,
+        typeshed_versions: _,
    } = Program::get(db).search_paths(db);

    let mut dynamic_paths = Vec::new();
@@ -315,12 +376,16 @@ pub(crate) fn dynamic_resolution_paths(db: &dyn Db) -> Vec<SearchPath> {
        let installations = all_pth_files.iter().flat_map(PthFile::items);

        for installation in installations {
+            let installation = system
+                .canonicalize_path(&installation)
+                .unwrap_or(installation);
+
            if existing_paths.insert(Cow::Owned(installation.clone())) {
-                match SearchPath::editable(system, installation) {
+                match SearchPath::editable(system, installation.clone()) {
                    Ok(search_path) => {
                        tracing::debug!(
                            "Adding editable installation to module resolution path {path}",
-                            path = search_path.as_system_path().unwrap()
+                            path = installation
                        );
                        dynamic_paths.push(search_path);
                    }
@@ -482,7 +547,7 @@ struct ModuleNameIngredient<'db> {
 fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, ModuleKind)> {
    let program = Program::get(db);
    let target_version = program.target_version(db);
-    let resolver_state = ResolverState::new(db, target_version);
+    let resolver_state = ResolverContext::new(db, target_version);
    let is_builtin_module =
        ruff_python_stdlib::sys::is_builtin_module(target_version.minor, name.as_str());

@@ -545,7 +610,7 @@ fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, Mod
 fn resolve_package<'a, 'db, I>(
    module_search_path: &SearchPath,
    components: I,
-    resolver_state: &ResolverState<'db>,
+    resolver_state: &ResolverContext<'db>,
 ) -> Result<ResolvedPackage, PackageKind>
 where
    I: Iterator<Item = &'a str>,
@@ -627,6 +692,21 @@ impl PackageKind {
    }
 }

+pub(super) struct ResolverContext<'db> {
+    pub(super) db: &'db dyn Db,
+    pub(super) target_version: PythonVersion,
+}
+
+impl<'db> ResolverContext<'db> {
+    pub(super) fn new(db: &'db dyn Db, target_version: PythonVersion) -> Self {
+        Self { db, target_version }
+    }
+
+    pub(super) fn vendored(&self) -> &VendoredFileSystem {
+        self.db.vendored()
+    }
+}
+
 #[cfg(test)]
 mod tests {
    use ruff_db::files::{system_path_to_file, File, FilePath};
@@ -781,7 +861,7 @@ mod tests {
                "Search path for {module_name} was unexpectedly {search_path:?}"
            );
            assert!(
-                search_path.is_stdlib_search_path(),
+                search_path.is_standard_library(),
                "Expected a stdlib search path, but got {search_path:?}"
            );
        }
@@ -877,7 +957,7 @@ mod tests {
                "Search path for {module_name} was unexpectedly {search_path:?}"
            );
            assert!(
-                search_path.is_stdlib_search_path(),
+                search_path.is_standard_library(),
                "Expected a stdlib search path, but got {search_path:?}"
            );
        }
@@ -1194,13 +1274,13 @@ mod tests {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::PY38,
                search_paths: SearchPathSettings {
                    extra_paths: vec![],
                    src_root: src.clone(),
                    custom_typeshed: Some(custom_typeshed.clone()),
-                    site_packages: vec![site_packages],
+                    site_packages: SitePackages::Known(vec![site_packages]),
                },
            },
        )
@@ -1699,13 +1779,16 @@ not_a_directory

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::default(),
                search_paths: SearchPathSettings {
                    extra_paths: vec![],
                    src_root: SystemPathBuf::from("/src"),
                    custom_typeshed: None,
-                    site_packages: vec![venv_site_packages, system_site_packages],
+                    site_packages: SitePackages::Known(vec![
+                        venv_site_packages,
+                        system_site_packages,
+                    ]),
                },
            },
        )
--- a/crates/red_knot_python_semantic/src/module_resolver/state.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/state.rs
@@ -1,25 +0,0 @@
-use ruff_db::vendored::VendoredFileSystem;
-
-use super::typeshed::LazyTypeshedVersions;
-use crate::db::Db;
-use crate::python_version::PythonVersion;
-
-pub(crate) struct ResolverState<'db> {
-    pub(crate) db: &'db dyn Db,
-    pub(crate) typeshed_versions: LazyTypeshedVersions<'db>,
-    pub(crate) target_version: PythonVersion,
-}
-
-impl<'db> ResolverState<'db> {
-    pub(crate) fn new(db: &'db dyn Db, target_version: PythonVersion) -> Self {
-        Self {
-            db,
-            typeshed_versions: LazyTypeshedVersions::new(),
-            target_version,
-        }
-    }
-
-    pub(crate) fn vendored(&self) -> &VendoredFileSystem {
-        self.db.vendored()
-    }
-}
--- a/crates/red_knot_python_semantic/src/module_resolver/testing.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/testing.rs
@@ -4,7 +4,7 @@ use ruff_db::vendored::VendoredPathBuf;
 use crate::db::tests::TestDb;
 use crate::program::{Program, SearchPathSettings};
 use crate::python_version::PythonVersion;
-use crate::ProgramSettings;
+use crate::{ProgramSettings, SitePackages};

 /// A test case for the module resolver.
 ///
@@ -179,6 +179,7 @@ impl TestCaseBuilder<UnspecifiedTypeshed> {
            first_party_files,
            site_packages_files,
        } = self;
+
        TestCaseBuilder {
            typeshed_option: typeshed,
            target_version,
@@ -195,6 +196,7 @@ impl TestCaseBuilder<UnspecifiedTypeshed> {
            site_packages,
            target_version,
        } = self.with_custom_typeshed(MockedTypeshed::default()).build();
+
        TestCase {
            db,
            src,
@@ -223,13 +225,13 @@ impl TestCaseBuilder<MockedTypeshed> {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version,
                search_paths: SearchPathSettings {
                    extra_paths: vec![],
                    src_root: src.clone(),
                    custom_typeshed: Some(typeshed.clone()),
-                    site_packages: vec![site_packages.clone()],
+                    site_packages: SitePackages::Known(vec![site_packages.clone()]),
                },
            },
        )
@@ -279,13 +281,11 @@ impl TestCaseBuilder<VendoredTypeshed> {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version,
                search_paths: SearchPathSettings {
-                    extra_paths: vec![],
-                    src_root: src.clone(),
-                    custom_typeshed: None,
-                    site_packages: vec![site_packages.clone()],
+                    site_packages: SitePackages::Known(vec![site_packages.clone()]),
+                    ..SearchPathSettings::new(src.clone())
                },
            },
        )
--- a/crates/red_knot_python_semantic/src/module_resolver/typeshed/mod.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/typeshed/mod.rs
@@ -1,6 +1,6 @@
 pub use self::vendored::vendored_typeshed_stubs;
 pub(super) use self::versions::{
-    parse_typeshed_versions, LazyTypeshedVersions, TypeshedVersionsParseError,
+    typeshed_versions, vendored_typeshed_versions, TypeshedVersions, TypeshedVersionsParseError,
    TypeshedVersionsQueryResult,
 };

--- a/crates/red_knot_python_semantic/src/module_resolver/typeshed/versions.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/typeshed/versions.rs
@@ -1,4 +1,3 @@
-use std::cell::OnceCell;
 use std::collections::BTreeMap;
 use std::fmt;
 use std::num::{NonZeroU16, NonZeroUsize};
@@ -6,78 +5,12 @@ use std::ops::{RangeFrom, RangeInclusive};
 use std::str::FromStr;

 use once_cell::sync::Lazy;
-use ruff_db::system::SystemPath;
 use rustc_hash::FxHashMap;

-use ruff_db::files::{system_path_to_file, File};
-
 use super::vendored::vendored_typeshed_stubs;
 use crate::db::Db;
 use crate::module_name::ModuleName;
-use crate::python_version::PythonVersion;
-
-#[derive(Debug)]
-pub(crate) struct LazyTypeshedVersions<'db>(OnceCell<&'db TypeshedVersions>);
-
-impl<'db> LazyTypeshedVersions<'db> {
-    #[must_use]
-    pub(crate) fn new() -> Self {
-        Self(OnceCell::new())
-    }
-
-    /// Query whether a module exists at runtime in the stdlib on a certain Python version.
-    ///
-    /// Simply probing whether a file exists in typeshed is insufficient for this question,
-    /// as a module in the stdlib may have been added in Python 3.10, but the typeshed stub
-    /// will still be available (either in a custom typeshed dir or in our vendored copy)
-    /// even if the user specified Python 3.8 as the target version.
-    ///
-    /// For top-level modules and packages, the VERSIONS file can always provide an unambiguous answer
-    /// as to whether the module exists on the specified target version. However, VERSIONS does not
-    /// provide comprehensive information on all submodules, meaning that this method sometimes
-    /// returns [`TypeshedVersionsQueryResult::MaybeExists`].
-    /// See [`TypeshedVersionsQueryResult`] for more details.
-    #[must_use]
-    pub(crate) fn query_module(
-        &self,
-        db: &'db dyn Db,
-        module: &ModuleName,
-        stdlib_root: Option<&SystemPath>,
-        target_version: PythonVersion,
-    ) -> TypeshedVersionsQueryResult {
-        let versions = self.0.get_or_init(|| {
-            let versions_path = if let Some(system_path) = stdlib_root {
-                system_path.join("VERSIONS")
-            } else {
-                return &VENDORED_VERSIONS;
-            };
-            let Ok(versions_file) = system_path_to_file(db.upcast(), &versions_path) else {
-                todo!(
-                    "Still need to figure out how to handle VERSIONS files being deleted \
-                    from custom typeshed directories! Expected a file to exist at {versions_path}"
-                )
-            };
-            // TODO(Alex/Micha): If VERSIONS is invalid,
-            // this should invalidate not just the specific module resolution we're currently attempting,
-            // but all type inference that depends on any standard-library types.
-            // Unwrapping here is not correct...
-            parse_typeshed_versions(db, versions_file).as_ref().unwrap()
-        });
-        versions.query_module(module, target_version)
-    }
-}
-
-#[salsa::tracked(return_ref)]
-pub(crate) fn parse_typeshed_versions(
-    db: &dyn Db,
-    versions_file: File,
-) -> Result<TypeshedVersions, TypeshedVersionsParseError> {
-    // TODO: Handle IO errors
-    let file_content = versions_file
-        .read_to_string(db.upcast())
-        .unwrap_or_default();
-    file_content.parse()
-}
+use crate::{Program, PythonVersion};

 static VENDORED_VERSIONS: Lazy<TypeshedVersions> = Lazy::new(|| {
    TypeshedVersions::from_str(
@@ -88,6 +21,14 @@ static VENDORED_VERSIONS: Lazy<TypeshedVersions> = Lazy::new(|| {
    .unwrap()
 });

+pub(crate) fn vendored_typeshed_versions() -> &'static TypeshedVersions {
+    &VENDORED_VERSIONS
+}
+
+pub(crate) fn typeshed_versions(db: &dyn Db) -> &TypeshedVersions {
+    Program::get(db).search_paths(db).typeshed_versions()
+}
+
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub(crate) struct TypeshedVersionsParseError {
    line_number: Option<NonZeroU16>,
@@ -174,7 +115,7 @@ impl TypeshedVersions {
    }

    #[must_use]
-    fn query_module(
+    pub(in crate::module_resolver) fn query_module(
        &self,
        module: &ModuleName,
        target_version: PythonVersion,
@@ -204,7 +145,7 @@ impl TypeshedVersions {
    }
 }

-/// Possible answers [`LazyTypeshedVersions::query_module()`] could give to the question:
+/// Possible answers [`TypeshedVersions::query_module()`] could give to the question:
 /// "Does this module exist in the stdlib at runtime on a certain target version?"
 #[derive(Debug, Copy, PartialEq, Eq, Clone, Hash)]
 pub(crate) enum TypeshedVersionsQueryResult {
--- a/crates/red_knot_python_semantic/src/program.rs
+++ b/crates/red_knot_python_semantic/src/program.rs
@@ -3,7 +3,7 @@ use anyhow::Context;
 use salsa::Durability;
 use salsa::Setter;

-use ruff_db::system::SystemPathBuf;
+use ruff_db::system::{SystemPath, SystemPathBuf};

 use crate::module_resolver::SearchPaths;
 use crate::Db;
@@ -12,33 +12,31 @@ use crate::Db;
 pub struct Program {
    pub target_version: PythonVersion,

-    #[default]
    #[return_ref]
    pub(crate) search_paths: SearchPaths,
 }

 impl Program {
-    pub fn from_settings(db: &dyn Db, settings: ProgramSettings) -> anyhow::Result<Self> {
+    pub fn from_settings(db: &dyn Db, settings: &ProgramSettings) -> anyhow::Result<Self> {
        let ProgramSettings {
            target_version,
            search_paths,
        } = settings;

-        tracing::info!("Target version: {target_version}");
+        tracing::info!("Target version: Python {target_version}");

        let search_paths = SearchPaths::from_settings(db, search_paths)
            .with_context(|| "Invalid search path settings")?;

-        Ok(Program::builder(settings.target_version)
+        Ok(Program::builder(settings.target_version, search_paths)
            .durability(Durability::HIGH)
-            .search_paths(search_paths)
            .new(db))
    }

    pub fn update_search_paths(
-        &self,
+        self,
        db: &mut dyn Db,
-        search_path_settings: SearchPathSettings,
+        search_path_settings: &SearchPathSettings,
    ) -> anyhow::Result<()> {
        let search_paths = SearchPaths::from_settings(db, search_path_settings)?;

@@ -49,16 +47,20 @@ impl Program {

        Ok(())
    }
+
+    pub fn custom_stdlib_search_path(self, db: &dyn Db) -> Option<&SystemPath> {
+        self.search_paths(db).custom_stdlib()
+    }
 }

-#[derive(Debug, Eq, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct ProgramSettings {
    pub target_version: PythonVersion,
    pub search_paths: SearchPathSettings,
 }

 /// Configures the search paths for module resolution.
-#[derive(Eq, PartialEq, Debug, Clone, Default)]
+#[derive(Eq, PartialEq, Debug, Clone)]
 pub struct SearchPathSettings {
    /// List of user-provided paths that should take first priority in the module resolution.
    /// Examples in other type checkers are mypy's MYPYPATH environment variable,
@@ -74,5 +76,25 @@ pub struct SearchPathSettings {
    pub custom_typeshed: Option<SystemPathBuf>,

    /// The path to the user's `site-packages` directory, where third-party packages from ``PyPI`` are installed.
-    pub site_packages: Vec<SystemPathBuf>,
+    pub site_packages: SitePackages,
+}
+
+impl SearchPathSettings {
+    pub fn new(src_root: SystemPathBuf) -> Self {
+        Self {
+            src_root,
+            extra_paths: vec![],
+            custom_typeshed: None,
+            site_packages: SitePackages::Known(vec![]),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum SitePackages {
+    Derived {
+        venv_path: SystemPathBuf,
+    },
+    /// Resolved site packages paths
+    Known(Vec<SystemPathBuf>),
 }
--- a/crates/red_knot_python_semantic/src/semantic_index.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index.rs
@@ -154,6 +154,10 @@ impl<'db> SemanticIndex<'db> {
        &self.scopes[id]
    }

+    pub(crate) fn scope_ids(&self) -> impl Iterator<Item = ScopeId> {
+        self.scope_ids_by_scope.iter().copied()
+    }
+
    /// Returns the id of the parent scope.
    pub(crate) fn parent_scope_id(&self, scope_id: FileScopeId) -> Option<FileScopeId> {
        let scope = self.scope(scope_id);
@@ -463,6 +467,25 @@ mod tests {
        ));
    }

+    #[test]
+    fn augmented_assignment() {
+        let TestCase { db, file } = test_case("x += 1");
+        let scope = global_scope(&db, file);
+        let global_table = symbol_table(&db, scope);
+
+        assert_eq!(names(&global_table), vec!["x"]);
+
+        let use_def = use_def_map(&db, scope);
+        let definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("x").unwrap())
+            .unwrap();
+
+        assert!(matches!(
+            definition.node(&db),
+            DefinitionKind::AugmentedAssignment(_)
+        ));
+    }
+
    #[test]
    fn class_scope() {
        let TestCase { db, file } = test_case(
@@ -767,6 +790,56 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
        assert_eq!(names(&inner_comprehension_symbol_table), vec!["x"]);
    }

+    #[test]
+    fn with_item_definition() {
+        let TestCase { db, file } = test_case(
+            "
+with item1 as x, item2 as y:
+    pass
+",
+        );
+
+        let index = semantic_index(&db, file);
+        let global_table = index.symbol_table(FileScopeId::global());
+
+        assert_eq!(names(&global_table), vec!["item1", "x", "item2", "y"]);
+
+        let use_def = index.use_def_map(FileScopeId::global());
+        for name in ["x", "y"] {
+            let Some(definition) = use_def.first_public_definition(
+                global_table.symbol_id_by_name(name).expect("symbol exists"),
+            ) else {
+                panic!("Expected with item definition for {name}");
+            };
+            assert!(matches!(definition.node(&db), DefinitionKind::WithItem(_)));
+        }
+    }
+
+    #[test]
+    fn with_item_unpacked_definition() {
+        let TestCase { db, file } = test_case(
+            "
+with context() as (x, y):
+    pass
+",
+        );
+
+        let index = semantic_index(&db, file);
+        let global_table = index.symbol_table(FileScopeId::global());
+
+        assert_eq!(names(&global_table), vec!["context", "x", "y"]);
+
+        let use_def = index.use_def_map(FileScopeId::global());
+        for name in ["x", "y"] {
+            let Some(definition) = use_def.first_public_definition(
+                global_table.symbol_id_by_name(name).expect("symbol exists"),
+            ) else {
+                panic!("Expected with item definition for {name}");
+            };
+            assert!(matches!(definition.node(&db), DefinitionKind::WithItem(_)));
+        }
+    }
+
    #[test]
    fn dupes() {
        let TestCase { db, file } = test_case(
@@ -998,4 +1071,28 @@ def x():
            vec!["bar", "foo", "Test", "<module>"]
        );
    }
+
+    #[test]
+    fn match_stmt_symbols() {
+        let TestCase { db, file } = test_case(
+            "
+match subject:
+    case a: ...
+    case [b, c, *d]: ...
+    case e as f: ...
+    case {'x': g, **h}: ...
+    case Foo(i, z=j): ...
+    case k | l: ...
+    case _: ...
+",
+        );
+
+        let global_table = symbol_table(&db, global_scope(&db, file));
+
+        assert!(global_table.symbol_by_name("Foo").unwrap().is_used());
+        assert_eq!(
+            names(&global_table),
+            vec!["subject", "a", "b", "c", "d", "f", "e", "h", "g", "Foo", "i", "j", "k", "l"]
+        );
+    }
 }
--- a/crates/red_knot_python_semantic/src/semantic_index/builder.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/builder.rs
@@ -7,7 +7,7 @@ use ruff_db::parsed::ParsedModule;
 use ruff_index::IndexVec;
 use ruff_python_ast as ast;
 use ruff_python_ast::name::Name;
-use ruff_python_ast::visitor::{walk_expr, walk_stmt, Visitor};
+use ruff_python_ast::visitor::{walk_expr, walk_pattern, walk_stmt, Visitor};
 use ruff_python_ast::AnyParameterRef;

 use crate::ast_node_ref::AstNodeRef;
@@ -26,6 +26,8 @@ use crate::semantic_index::use_def::{FlowSnapshot, UseDefMapBuilder};
 use crate::semantic_index::SemanticIndex;
 use crate::Db;

+use super::definition::WithItemDefinitionNodeRef;
+
 pub(super) struct SemanticIndexBuilder<'db> {
    // Builder state
    db: &'db dyn Db,
@@ -495,6 +497,20 @@ where
                self.visit_expr(&node.target);
                self.current_assignment = None;
            }
+            ast::Stmt::AugAssign(
+                aug_assign @ ast::StmtAugAssign {
+                    range: _,
+                    target,
+                    op: _,
+                    value,
+                },
+            ) => {
+                debug_assert!(self.current_assignment.is_none());
+                self.visit_expr(value);
+                self.current_assignment = Some(aug_assign.into());
+                self.visit_expr(target);
+                self.current_assignment = None;
+            }
            ast::Stmt::If(node) => {
                self.visit_expr(&node.test);
                let pre_if = self.flow_snapshot();
@@ -547,6 +563,18 @@ where
                    self.flow_merge(break_state);
                }
            }
+            ast::Stmt::With(ast::StmtWith { items, body, .. }) => {
+                for item in items {
+                    self.visit_expr(&item.context_expr);
+                    if let Some(optional_vars) = item.optional_vars.as_deref() {
+                        self.add_standalone_expression(&item.context_expr);
+                        self.current_assignment = Some(item.into());
+                        self.visit_expr(optional_vars);
+                        self.current_assignment = None;
+                    }
+                }
+                self.visit_body(body);
+            }
            ast::Stmt::Break(_) => {
                self.loop_break_states.push(self.flow_snapshot());
            }
@@ -563,12 +591,21 @@ where

        match expr {
            ast::Expr::Name(name_node @ ast::ExprName { id, ctx, .. }) => {
-                let flags = match ctx {
+                let mut flags = match ctx {
                    ast::ExprContext::Load => SymbolFlags::IS_USED,
                    ast::ExprContext::Store => SymbolFlags::IS_DEFINED,
                    ast::ExprContext::Del => SymbolFlags::IS_DEFINED,
                    ast::ExprContext::Invalid => SymbolFlags::empty(),
                };
+                if matches!(
+                    self.current_assignment,
+                    Some(CurrentAssignment::AugAssign(_))
+                ) && !ctx.is_invalid()
+                {
+                    // For augmented assignment, the target expression is also used, so we should
+                    // record that as a use.
+                    flags |= SymbolFlags::IS_USED;
+                }
                let symbol = self.add_or_update_symbol(id.clone(), flags);
                if flags.contains(SymbolFlags::IS_DEFINED) {
                    match self.current_assignment {
@@ -584,6 +621,9 @@ where
                        Some(CurrentAssignment::AnnAssign(ann_assign)) => {
                            self.add_definition(symbol, ann_assign);
                        }
+                        Some(CurrentAssignment::AugAssign(aug_assign)) => {
+                            self.add_definition(symbol, aug_assign);
+                        }
                        Some(CurrentAssignment::Named(named)) => {
                            // TODO(dhruvmanila): If the current scope is a comprehension, then the
                            // named expression is implicitly nonlocal. This is yet to be
@@ -596,6 +636,15 @@ where
                                ComprehensionDefinitionNodeRef { node, first },
                            );
                        }
+                        Some(CurrentAssignment::WithItem(with_item)) => {
+                            self.add_definition(
+                                symbol,
+                                WithItemDefinitionNodeRef {
+                                    node: with_item,
+                                    target: name_node,
+                                },
+                            );
+                        }
                        None => {}
                    }
                }
@@ -609,11 +658,11 @@ where
            }
            ast::Expr::Named(node) => {
                debug_assert!(self.current_assignment.is_none());
-                self.current_assignment = Some(node.into());
                // TODO walrus in comprehensions is implicitly nonlocal
+                self.visit_expr(&node.value);
+                self.current_assignment = Some(node.into());
                self.visit_expr(&node.target);
                self.current_assignment = None;
-                self.visit_expr(&node.value);
            }
            ast::Expr::Lambda(lambda) => {
                if let Some(parameters) = &lambda.parameters {
@@ -721,17 +770,38 @@ where
            self.visit_parameter(parameter);
        }
    }
+
+    fn visit_pattern(&mut self, pattern: &'ast ast::Pattern) {
+        if let ast::Pattern::MatchAs(ast::PatternMatchAs {
+            name: Some(name), ..
+        })
+        | ast::Pattern::MatchStar(ast::PatternMatchStar {
+            name: Some(name),
+            range: _,
+        })
+        | ast::Pattern::MatchMapping(ast::PatternMatchMapping {
+            rest: Some(name), ..
+        }) = pattern
+        {
+            // TODO(dhruvmanila): Add definition
+            self.add_or_update_symbol(name.id.clone(), SymbolFlags::IS_DEFINED);
+        }
+
+        walk_pattern(self, pattern);
+    }
 }

 #[derive(Copy, Clone, Debug)]
 enum CurrentAssignment<'a> {
    Assign(&'a ast::StmtAssign),
    AnnAssign(&'a ast::StmtAnnAssign),
+    AugAssign(&'a ast::StmtAugAssign),
    Named(&'a ast::ExprNamed),
    Comprehension {
        node: &'a ast::Comprehension,
        first: bool,
    },
+    WithItem(&'a ast::WithItem),
 }

 impl<'a> From<&'a ast::StmtAssign> for CurrentAssignment<'a> {
@@ -746,8 +816,20 @@ impl<'a> From<&'a ast::StmtAnnAssign> for CurrentAssignment<'a> {
    }
 }

+impl<'a> From<&'a ast::StmtAugAssign> for CurrentAssignment<'a> {
+    fn from(value: &'a ast::StmtAugAssign) -> Self {
+        Self::AugAssign(value)
+    }
+}
+
 impl<'a> From<&'a ast::ExprNamed> for CurrentAssignment<'a> {
    fn from(value: &'a ast::ExprNamed) -> Self {
        Self::Named(value)
    }
 }
+
+impl<'a> From<&'a ast::WithItem> for CurrentAssignment<'a> {
+    fn from(value: &'a ast::WithItem) -> Self {
+        Self::WithItem(value)
+    }
+}
--- a/crates/red_knot_python_semantic/src/semantic_index/definition.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/definition.rs
@@ -44,8 +44,10 @@ pub(crate) enum DefinitionNodeRef<'a> {
    NamedExpression(&'a ast::ExprNamed),
    Assignment(AssignmentDefinitionNodeRef<'a>),
    AnnotatedAssignment(&'a ast::StmtAnnAssign),
+    AugmentedAssignment(&'a ast::StmtAugAssign),
    Comprehension(ComprehensionDefinitionNodeRef<'a>),
    Parameter(ast::AnyParameterRef<'a>),
+    WithItem(WithItemDefinitionNodeRef<'a>),
 }

 impl<'a> From<&'a ast::StmtFunctionDef> for DefinitionNodeRef<'a> {
@@ -72,6 +74,12 @@ impl<'a> From<&'a ast::StmtAnnAssign> for DefinitionNodeRef<'a> {
    }
 }

+impl<'a> From<&'a ast::StmtAugAssign> for DefinitionNodeRef<'a> {
+    fn from(node: &'a ast::StmtAugAssign) -> Self {
+        Self::AugmentedAssignment(node)
+    }
+}
+
 impl<'a> From<&'a ast::Alias> for DefinitionNodeRef<'a> {
    fn from(node_ref: &'a ast::Alias) -> Self {
        Self::Import(node_ref)
@@ -90,6 +98,12 @@ impl<'a> From<AssignmentDefinitionNodeRef<'a>> for DefinitionNodeRef<'a> {
    }
 }

+impl<'a> From<WithItemDefinitionNodeRef<'a>> for DefinitionNodeRef<'a> {
+    fn from(node_ref: WithItemDefinitionNodeRef<'a>) -> Self {
+        Self::WithItem(node_ref)
+    }
+}
+
 impl<'a> From<ComprehensionDefinitionNodeRef<'a>> for DefinitionNodeRef<'a> {
    fn from(node: ComprehensionDefinitionNodeRef<'a>) -> Self {
        Self::Comprehension(node)
@@ -114,6 +128,12 @@ pub(crate) struct AssignmentDefinitionNodeRef<'a> {
    pub(crate) target: &'a ast::ExprName,
 }

+#[derive(Copy, Clone, Debug)]
+pub(crate) struct WithItemDefinitionNodeRef<'a> {
+    pub(crate) node: &'a ast::WithItem,
+    pub(crate) target: &'a ast::ExprName,
+}
+
 #[derive(Copy, Clone, Debug)]
 pub(crate) struct ComprehensionDefinitionNodeRef<'a> {
    pub(crate) node: &'a ast::Comprehension,
@@ -151,6 +171,9 @@ impl DefinitionNodeRef<'_> {
            DefinitionNodeRef::AnnotatedAssignment(assign) => {
                DefinitionKind::AnnotatedAssignment(AstNodeRef::new(parsed, assign))
            }
+            DefinitionNodeRef::AugmentedAssignment(augmented_assignment) => {
+                DefinitionKind::AugmentedAssignment(AstNodeRef::new(parsed, augmented_assignment))
+            }
            DefinitionNodeRef::Comprehension(ComprehensionDefinitionNodeRef { node, first }) => {
                DefinitionKind::Comprehension(ComprehensionDefinitionKind {
                    node: AstNodeRef::new(parsed, node),
@@ -165,6 +188,12 @@ impl DefinitionNodeRef<'_> {
                    DefinitionKind::ParameterWithDefault(AstNodeRef::new(parsed, parameter))
                }
            },
+            DefinitionNodeRef::WithItem(WithItemDefinitionNodeRef { node, target }) => {
+                DefinitionKind::WithItem(WithItemDefinitionKind {
+                    node: AstNodeRef::new(parsed.clone(), node),
+                    target: AstNodeRef::new(parsed, target),
+                })
+            }
        }
    }

@@ -182,11 +211,13 @@ impl DefinitionNodeRef<'_> {
                target,
            }) => target.into(),
            Self::AnnotatedAssignment(node) => node.into(),
+            Self::AugmentedAssignment(node) => node.into(),
            Self::Comprehension(ComprehensionDefinitionNodeRef { node, first: _ }) => node.into(),
            Self::Parameter(node) => match node {
                ast::AnyParameterRef::Variadic(parameter) => parameter.into(),
                ast::AnyParameterRef::NonVariadic(parameter) => parameter.into(),
            },
+            Self::WithItem(WithItemDefinitionNodeRef { node: _, target }) => target.into(),
        }
    }
 }
@@ -200,9 +231,11 @@ pub enum DefinitionKind {
    NamedExpression(AstNodeRef<ast::ExprNamed>),
    Assignment(AssignmentDefinitionKind),
    AnnotatedAssignment(AstNodeRef<ast::StmtAnnAssign>),
+    AugmentedAssignment(AstNodeRef<ast::StmtAugAssign>),
    Comprehension(ComprehensionDefinitionKind),
    Parameter(AstNodeRef<ast::Parameter>),
    ParameterWithDefault(AstNodeRef<ast::ParameterWithDefault>),
+    WithItem(WithItemDefinitionKind),
 }

 #[derive(Clone, Debug)]
@@ -238,7 +271,6 @@ impl ImportFromDefinitionKind {
 }

 #[derive(Clone, Debug)]
-#[allow(dead_code)]
 pub struct AssignmentDefinitionKind {
    assignment: AstNodeRef<ast::StmtAssign>,
    target: AstNodeRef<ast::ExprName>,
@@ -254,6 +286,22 @@ impl AssignmentDefinitionKind {
    }
 }

+#[derive(Clone, Debug)]
+pub struct WithItemDefinitionKind {
+    node: AstNodeRef<ast::WithItem>,
+    target: AstNodeRef<ast::ExprName>,
+}
+
+impl WithItemDefinitionKind {
+    pub(crate) fn node(&self) -> &ast::WithItem {
+        self.node.node()
+    }
+
+    pub(crate) fn target(&self) -> &ast::ExprName {
+        self.target.node()
+    }
+}
+
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
 pub(crate) struct DefinitionNodeKey(NodeKey);

@@ -293,6 +341,12 @@ impl From<&ast::StmtAnnAssign> for DefinitionNodeKey {
    }
 }

+impl From<&ast::StmtAugAssign> for DefinitionNodeKey {
+    fn from(node: &ast::StmtAugAssign) -> Self {
+        Self(NodeKey::from_node(node))
+    }
+}
+
 impl From<&ast::Comprehension> for DefinitionNodeKey {
    fn from(node: &ast::Comprehension) -> Self {
        Self(NodeKey::from_node(node))
--- a/crates/red_knot_python_semantic/src/semantic_model.rs
+++ b/crates/red_knot_python_semantic/src/semantic_model.rs
@@ -184,14 +184,9 @@ mod tests {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::default(),
-                search_paths: SearchPathSettings {
-                    extra_paths: vec![],
-                    src_root: SystemPathBuf::from("/src"),
-                    site_packages: vec![],
-                    custom_typeshed: None,
-                },
+                search_paths: SearchPathSettings::new(SystemPathBuf::from("/src")),
            },
        )?;

--- a/crates/red_knot_python_semantic/src/site_packages.rs
+++ b/crates/red_knot_python_semantic/src/site_packages.rs
@@ -13,9 +13,10 @@ use std::io;
 use std::num::NonZeroUsize;
 use std::ops::Deref;

-use red_knot_python_semantic::PythonVersion;
 use ruff_db::system::{System, SystemPath, SystemPathBuf};

+use crate::PythonVersion;
+
 type SitePackagesDiscoveryResult<T> = Result<T, SitePackagesDiscoveryError>;

 /// Abstraction for a Python virtual environment.
@@ -24,7 +25,7 @@ type SitePackagesDiscoveryResult<T> = Result<T, SitePackagesDiscoveryError>;
 /// The format of this file is not defined anywhere, and exactly which keys are present
 /// depends on the tool that was used to create the virtual environment.
 #[derive(Debug)]
-pub struct VirtualEnvironment {
+pub(crate) struct VirtualEnvironment {
    venv_path: SysPrefixPath,
    base_executable_home_path: PythonHomePath,
    include_system_site_packages: bool,
@@ -41,7 +42,7 @@ pub struct VirtualEnvironment {
 }

 impl VirtualEnvironment {
-    pub fn new(
+    pub(crate) fn new(
        path: impl AsRef<SystemPath>,
        system: &dyn System,
    ) -> SitePackagesDiscoveryResult<Self> {
@@ -55,7 +56,7 @@ impl VirtualEnvironment {

        let venv_path = SysPrefixPath::new(path, system)?;
        let pyvenv_cfg_path = venv_path.join("pyvenv.cfg");
-        tracing::debug!("Attempting to parse virtual environment metadata at {pyvenv_cfg_path}");
+        tracing::debug!("Attempting to parse virtual environment metadata at '{pyvenv_cfg_path}'");

        let pyvenv_cfg = system
            .read_to_string(&pyvenv_cfg_path)
@@ -157,7 +158,7 @@ impl VirtualEnvironment {
    /// Return a list of `site-packages` directories that are available from this virtual environment
    ///
    /// See the documentation for `site_packages_dir_from_sys_prefix` for more details.
-    pub fn site_packages_directories(
+    pub(crate) fn site_packages_directories(
        &self,
        system: &dyn System,
    ) -> SitePackagesDiscoveryResult<Vec<SystemPathBuf>> {
@@ -191,7 +192,7 @@ impl VirtualEnvironment {
            } else {
                tracing::warn!(
                    "Failed to resolve `sys.prefix` of the system Python installation \
-from the `home` value in the `pyvenv.cfg` file at {}. \
+from the `home` value in the `pyvenv.cfg` file at '{}'. \
 System site-packages will not be used for module resolution.",
                    venv_path.join("pyvenv.cfg")
                );
@@ -204,7 +205,7 @@ System site-packages will not be used for module resolution.",
 }

 #[derive(Debug, thiserror::Error)]
-pub enum SitePackagesDiscoveryError {
+pub(crate) enum SitePackagesDiscoveryError {
    #[error("Invalid --venv-path argument: {0} could not be canonicalized")]
    VenvDirCanonicalizationError(SystemPathBuf, #[source] io::Error),
    #[error("Invalid --venv-path argument: {0} does not point to a directory on disk")]
@@ -221,7 +222,7 @@ pub enum SitePackagesDiscoveryError {

 /// The various ways in which parsing a `pyvenv.cfg` file could fail
 #[derive(Debug)]
-pub enum PyvenvCfgParseErrorKind {
+pub(crate) enum PyvenvCfgParseErrorKind {
    TooManyEquals { line_number: NonZeroUsize },
    MalformedKeyValuePair { line_number: NonZeroUsize },
    NoHomeKey,
@@ -370,7 +371,7 @@ fn site_packages_directory_from_sys_prefix(
 ///
 /// [`sys.prefix`]: https://docs.python.org/3/library/sys.html#sys.prefix
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub struct SysPrefixPath(SystemPathBuf);
+pub(crate) struct SysPrefixPath(SystemPathBuf);

 impl SysPrefixPath {
    fn new(
@@ -425,7 +426,7 @@ impl Deref for SysPrefixPath {

 impl fmt::Display for SysPrefixPath {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "`sys.prefix` path {}", self.0)
+        write!(f, "`sys.prefix` path '{}'", self.0)
    }
 }

@@ -482,7 +483,7 @@ impl Deref for PythonHomePath {

 impl fmt::Display for PythonHomePath {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "`home` location {}", self.0)
+        write!(f, "`home` location '{}'", self.0)
    }
 }

--- a/crates/red_knot_python_semantic/src/types.rs
+++ b/crates/red_knot_python_semantic/src/types.rs
@@ -5,21 +5,37 @@ use crate::builtins::builtins_scope;
 use crate::semantic_index::definition::Definition;
 use crate::semantic_index::symbol::{ScopeId, ScopedSymbolId};
 use crate::semantic_index::{
-    global_scope, symbol_table, use_def_map, DefinitionWithConstraints,
+    global_scope, semantic_index, symbol_table, use_def_map, DefinitionWithConstraints,
    DefinitionWithConstraintsIterator,
 };
 use crate::types::narrow::narrowing_constraint;
 use crate::{Db, FxOrderSet};

+pub(crate) use self::builder::{IntersectionBuilder, UnionBuilder};
+pub(crate) use self::diagnostic::TypeCheckDiagnostics;
+pub(crate) use self::infer::{
+    infer_definition_types, infer_expression_types, infer_scope_types, TypeInference,
+};
+
 mod builder;
+mod diagnostic;
 mod display;
 mod infer;
 mod narrow;

-pub(crate) use self::builder::{IntersectionBuilder, UnionBuilder};
-pub(crate) use self::infer::{
-    infer_definition_types, infer_expression_types, infer_scope_types, TypeInference,
-};
+pub fn check_types(db: &dyn Db, file: File) -> TypeCheckDiagnostics {
+    let _span = tracing::trace_span!("check_types", file=?file.path(db)).entered();
+
+    let index = semantic_index(db, file);
+    let mut diagnostics = TypeCheckDiagnostics::new();
+
+    for scope_id in index.scope_ids() {
+        let result = infer_scope_types(db, scope_id);
+        diagnostics.extend(result.diagnostics());
+    }
+
+    diagnostics
+}

 /// Infer the public type of a symbol (its type as seen from outside its scope).
 pub(crate) fn symbol_ty<'db>(
@@ -165,6 +181,8 @@ pub enum Type<'db> {
    IntLiteral(i64),
    /// A boolean literal, either `True` or `False`.
    BooleanLiteral(bool),
+    /// A bytes literal
+    BytesLiteral(BytesLiteralType<'db>),
    // TODO protocols, callable types, overloads, generics, type vars
 }

@@ -206,20 +224,42 @@ impl<'db> Type<'db> {
        }
    }

+    /// Resolve a member access of a type.
+    ///
+    /// For example, if `foo` is `Type::Instance(<Bar>)`,
+    /// `foo.member(&db, "baz")` returns the type of `baz` attributes
+    /// as accessed from instances of the `Bar` class.
+    ///
+    /// TODO: use of this method currently requires manually checking
+    /// whether the returned type is `Unknown`/`Unbound`
+    /// (or a union with `Unknown`/`Unbound`) in many places.
+    /// Ideally we'd use a more type-safe pattern, such as returning
+    /// an `Option` or a `Result` from this method, which would force
+    /// us to explicitly consider whether to handle an error or propagate
+    /// it up the call stack.
    #[must_use]
    pub fn member(&self, db: &'db dyn Db, name: &Name) -> Type<'db> {
        match self {
            Type::Any => Type::Any,
-            Type::Never => todo!("attribute lookup on Never type"),
+            Type::Never => {
+                // TODO: attribute lookup on Never type
+                Type::Unknown
+            }
            Type::Unknown => Type::Unknown,
            Type::Unbound => Type::Unbound,
-            Type::None => todo!("attribute lookup on None type"),
-            Type::Function(_) => todo!("attribute lookup on Function type"),
+            Type::None => {
+                // TODO: attribute lookup on None type
+                Type::Unknown
+            }
+            Type::Function(_) => {
+                // TODO: attribute lookup on function type
+                Type::Unknown
+            }
            Type::Module(file) => global_symbol_ty_by_name(db, *file, name),
            Type::Class(class) => class.class_member(db, name),
            Type::Instance(_) => {
                // TODO MRO? get_own_instance_member, get_instance_member
-                todo!("attribute lookup on Instance type")
+                Type::Unknown
            }
            Type::Union(union) => union
                .elements(db)
@@ -231,13 +271,17 @@ impl<'db> Type<'db> {
            Type::Intersection(_) => {
                // TODO perform the get_member on each type in the intersection
                // TODO return the intersection of those results
-                todo!("attribute lookup on Intersection type")
+                Type::Unknown
            }
            Type::IntLiteral(_) => {
                // TODO raise error
                Type::Unknown
            }
            Type::BooleanLiteral(_) => Type::Unknown,
+            Type::BytesLiteral(_) => {
+                // TODO defer to Type::Instance(<bytes from typeshed>).member
+                Type::Unknown
+            }
        }
    }

@@ -333,3 +377,116 @@ pub struct IntersectionType<'db> {
    /// directly in intersections rather than as a separate type.
    negative: FxOrderSet<Type<'db>>,
 }
+
+#[salsa::interned]
+pub struct BytesLiteralType<'db> {
+    #[return_ref]
+    value: Box<[u8]>,
+}
+
+#[cfg(test)]
+mod tests {
+    use anyhow::Context;
+
+    use ruff_db::files::system_path_to_file;
+    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
+
+    use crate::db::tests::TestDb;
+    use crate::{Program, ProgramSettings, PythonVersion, SearchPathSettings};
+
+    use super::TypeCheckDiagnostics;
+
+    fn setup_db() -> TestDb {
+        let db = TestDb::new();
+        db.memory_file_system()
+            .create_directory_all("/src")
+            .unwrap();
+
+        Program::from_settings(
+            &db,
+            &ProgramSettings {
+                target_version: PythonVersion::default(),
+                search_paths: SearchPathSettings::new(SystemPathBuf::from("/src")),
+            },
+        )
+        .expect("Valid search path settings");
+
+        db
+    }
+
+    fn assert_diagnostic_messages(diagnostics: &TypeCheckDiagnostics, expected: &[&str]) {
+        let messages: Vec<&str> = diagnostics
+            .iter()
+            .map(|diagnostic| diagnostic.message())
+            .collect();
+        assert_eq!(&messages, expected);
+    }
+
+    #[test]
+    fn unresolved_import_statement() -> anyhow::Result<()> {
+        let mut db = setup_db();
+
+        db.write_file("src/foo.py", "import bar\n")
+            .context("Failed to write foo.py")?;
+
+        let foo = system_path_to_file(&db, "src/foo.py").context("Failed to resolve foo.py")?;
+
+        let diagnostics = super::check_types(&db, foo);
+        assert_diagnostic_messages(&diagnostics, &["Import 'bar' could not be resolved."]);
+
+        Ok(())
+    }
+
+    #[test]
+    fn unresolved_import_from_statement() {
+        let mut db = setup_db();
+
+        db.write_file("src/foo.py", "from bar import baz\n")
+            .unwrap();
+        let foo = system_path_to_file(&db, "src/foo.py").unwrap();
+        let diagnostics = super::check_types(&db, foo);
+        assert_diagnostic_messages(&diagnostics, &["Import 'bar' could not be resolved."]);
+    }
+
+    #[test]
+    fn unresolved_import_from_resolved_module() {
+        let mut db = setup_db();
+
+        db.write_files([("/src/a.py", ""), ("/src/b.py", "from a import thing")])
+            .unwrap();
+
+        let b_file = system_path_to_file(&db, "/src/b.py").unwrap();
+        let b_file_diagnostics = super::check_types(&db, b_file);
+        assert_diagnostic_messages(
+            &b_file_diagnostics,
+            &["Could not resolve import of 'thing' from 'a'"],
+        );
+    }
+
+    #[ignore = "\
+A spurious second 'Unresolved import' diagnostic message is emitted on `b.py`, \
+despite the symbol existing in the symbol table for `a.py`"]
+    #[test]
+    fn resolved_import_of_symbol_from_unresolved_import() {
+        let mut db = setup_db();
+
+        db.write_files([
+            ("/src/a.py", "import foo as foo"),
+            ("/src/b.py", "from a import foo"),
+        ])
+        .unwrap();
+
+        let a_file = system_path_to_file(&db, "/src/a.py").unwrap();
+        let a_file_diagnostics = super::check_types(&db, a_file);
+        assert_diagnostic_messages(
+            &a_file_diagnostics,
+            &["Import 'foo' could not be resolved."],
+        );
+
+        // Importing the unresolved import into a second first-party file should not trigger
+        // an additional "unresolved import" violation
+        let b_file = system_path_to_file(&db, "/src/b.py").unwrap();
+        let b_file_diagnostics = super::check_types(&db, b_file);
+        assert_eq!(&*b_file_diagnostics, &[]);
+    }
+}
--- a/crates/red_knot_python_semantic/src/types/diagnostic.rs
+++ b/crates/red_knot_python_semantic/src/types/diagnostic.rs
@@ -0,0 +1,111 @@
+use ruff_db::files::File;
+use ruff_text_size::{Ranged, TextRange};
+use std::fmt::Formatter;
+use std::ops::Deref;
+use std::sync::Arc;
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct TypeCheckDiagnostic {
+    // TODO: Don't use string keys for rules
+    pub(super) rule: String,
+    pub(super) message: String,
+    pub(super) range: TextRange,
+    pub(super) file: File,
+}
+
+impl TypeCheckDiagnostic {
+    pub fn rule(&self) -> &str {
+        &self.rule
+    }
+
+    pub fn message(&self) -> &str {
+        &self.message
+    }
+
+    pub fn file(&self) -> File {
+        self.file
+    }
+}
+
+impl Ranged for TypeCheckDiagnostic {
+    fn range(&self) -> TextRange {
+        self.range
+    }
+}
+
+/// A collection of type check diagnostics.
+///
+/// The diagnostics are wrapped in an `Arc` because they need to be cloned multiple times
+/// when going from `infer_expression` to `check_file`. We could consider
+/// making [`TypeCheckDiagnostic`] a Salsa struct to have them Arena-allocated (once the Tables refactor is done).
+/// Using Salsa struct does have the downside that it leaks the Salsa dependency into diagnostics and
+/// each Salsa-struct comes with an overhead.
+#[derive(Default, Eq, PartialEq)]
+pub struct TypeCheckDiagnostics {
+    inner: Vec<std::sync::Arc<TypeCheckDiagnostic>>,
+}
+
+impl TypeCheckDiagnostics {
+    pub fn new() -> Self {
+        Self { inner: Vec::new() }
+    }
+
+    pub(super) fn push(&mut self, diagnostic: TypeCheckDiagnostic) {
+        self.inner.push(Arc::new(diagnostic));
+    }
+
+    pub(crate) fn shrink_to_fit(&mut self) {
+        self.inner.shrink_to_fit();
+    }
+}
+
+impl Extend<TypeCheckDiagnostic> for TypeCheckDiagnostics {
+    fn extend<T: IntoIterator<Item = TypeCheckDiagnostic>>(&mut self, iter: T) {
+        self.inner.extend(iter.into_iter().map(std::sync::Arc::new));
+    }
+}
+
+impl Extend<std::sync::Arc<TypeCheckDiagnostic>> for TypeCheckDiagnostics {
+    fn extend<T: IntoIterator<Item = Arc<TypeCheckDiagnostic>>>(&mut self, iter: T) {
+        self.inner.extend(iter);
+    }
+}
+
+impl<'a> Extend<&'a std::sync::Arc<TypeCheckDiagnostic>> for TypeCheckDiagnostics {
+    fn extend<T: IntoIterator<Item = &'a Arc<TypeCheckDiagnostic>>>(&mut self, iter: T) {
+        self.inner
+            .extend(iter.into_iter().map(std::sync::Arc::clone));
+    }
+}
+
+impl std::fmt::Debug for TypeCheckDiagnostics {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.inner.fmt(f)
+    }
+}
+
+impl Deref for TypeCheckDiagnostics {
+    type Target = [std::sync::Arc<TypeCheckDiagnostic>];
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl IntoIterator for TypeCheckDiagnostics {
+    type Item = Arc<TypeCheckDiagnostic>;
+    type IntoIter = std::vec::IntoIter<std::sync::Arc<TypeCheckDiagnostic>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.inner.into_iter()
+    }
+}
+
+impl<'a> IntoIterator for &'a TypeCheckDiagnostics {
+    type Item = &'a Arc<TypeCheckDiagnostic>;
+    type IntoIter = std::slice::Iter<'a, std::sync::Arc<TypeCheckDiagnostic>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.inner.iter()
+    }
+}
--- a/crates/red_knot_python_semantic/src/types/display.rs
+++ b/crates/red_knot_python_semantic/src/types/display.rs
@@ -2,6 +2,9 @@

 use std::fmt::{Display, Formatter};

+use ruff_python_ast::str::Quote;
+use ruff_python_literal::escape::AsciiEscape;
+
 use crate::types::{IntersectionType, Type, UnionType};
 use crate::Db;

@@ -38,6 +41,14 @@ impl Display for DisplayType<'_> {
            Type::BooleanLiteral(boolean) => {
                write!(f, "Literal[{}]", if *boolean { "True" } else { "False" })
            }
+            Type::BytesLiteral(bytes) => {
+                let escape =
+                    AsciiEscape::with_preferred_quote(bytes.value(self.db).as_ref(), Quote::Double);
+
+                f.write_str("Literal[")?;
+                escape.bytes_repr().write(f)?;
+                f.write_str("]")
+            }
        }
    }
 }
--- a/crates/red_knot_python_semantic/src/types/infer.rs
+++ b/crates/red_knot_python_semantic/src/types/infer.rs
@@ -29,7 +29,8 @@ use salsa::plumbing::AsId;
 use ruff_db::files::File;
 use ruff_db::parsed::parsed_module;
 use ruff_python_ast as ast;
-use ruff_python_ast::{Expr, ExprContext};
+use ruff_python_ast::{AnyNodeRef, ExprContext};
+use ruff_text_size::Ranged;

 use crate::builtins::builtins_scope;
 use crate::module_name::ModuleName;
@@ -40,9 +41,10 @@ use crate::semantic_index::expression::Expression;
 use crate::semantic_index::semantic_index;
 use crate::semantic_index::symbol::{FileScopeId, NodeWithScopeKind, NodeWithScopeRef, ScopeId};
 use crate::semantic_index::SemanticIndex;
+use crate::types::diagnostic::{TypeCheckDiagnostic, TypeCheckDiagnostics};
 use crate::types::{
-    builtins_symbol_ty_by_name, definitions_ty, global_symbol_ty_by_name, ClassType, FunctionType,
-    Name, Type, UnionBuilder,
+    builtins_symbol_ty_by_name, definitions_ty, global_symbol_ty_by_name, BytesLiteralType,
+    ClassType, FunctionType, Name, Type, UnionBuilder,
 };
 use crate::Db;

@@ -123,13 +125,16 @@ pub(crate) enum InferenceRegion<'db> {
 }

 /// The inferred types for a single region.
-#[derive(Debug, Eq, PartialEq, Default, Clone)]
+#[derive(Debug, Eq, PartialEq, Default)]
 pub(crate) struct TypeInference<'db> {
    /// The types of every expression in this region.
    expressions: FxHashMap<ScopedExpressionId, Type<'db>>,

    /// The types of every definition in this region.
    definitions: FxHashMap<Definition<'db>, Type<'db>>,
+
+    /// The diagnostics for this region.
+    diagnostics: TypeCheckDiagnostics,
 }

 impl<'db> TypeInference<'db> {
@@ -142,9 +147,14 @@ impl<'db> TypeInference<'db> {
        self.definitions[&definition]
    }

+    pub(crate) fn diagnostics(&self) -> &[std::sync::Arc<TypeCheckDiagnostic>] {
+        &self.diagnostics
+    }
+
    fn shrink_to_fit(&mut self) {
        self.expressions.shrink_to_fit();
        self.definitions.shrink_to_fit();
+        self.diagnostics.shrink_to_fit();
    }
 }

@@ -235,6 +245,7 @@ impl<'db> TypeInferenceBuilder<'db> {
    fn extend(&mut self, inference: &TypeInference<'db>) {
        self.types.definitions.extend(inference.definitions.iter());
        self.types.expressions.extend(inference.expressions.iter());
+        self.types.diagnostics.extend(&inference.diagnostics);
    }

    /// Infers types in the given [`InferenceRegion`].
@@ -303,6 +314,9 @@ impl<'db> TypeInferenceBuilder<'db> {
            DefinitionKind::AnnotatedAssignment(annotated_assignment) => {
                self.infer_annotated_assignment_definition(annotated_assignment.node(), definition);
            }
+            DefinitionKind::AugmentedAssignment(augmented_assignment) => {
+                self.infer_augment_assignment_definition(augmented_assignment.node(), definition);
+            }
            DefinitionKind::NamedExpression(named_expression) => {
                self.infer_named_expression_definition(named_expression.node(), definition);
            }
@@ -319,6 +333,9 @@ impl<'db> TypeInferenceBuilder<'db> {
            DefinitionKind::ParameterWithDefault(parameter_with_default) => {
                self.infer_parameter_with_default_definition(parameter_with_default, definition);
            }
+            DefinitionKind::WithItem(with_item) => {
+                self.infer_with_item_definition(with_item.target(), with_item.node(), definition);
+            }
        }
    }

@@ -604,13 +621,42 @@ impl<'db> TypeInferenceBuilder<'db> {
        } = with_statement;

        for item in items {
-            self.infer_expression(&item.context_expr);
-            self.infer_optional_expression(item.optional_vars.as_deref());
+            match item.optional_vars.as_deref() {
+                Some(ast::Expr::Name(name)) => {
+                    self.infer_definition(name);
+                }
+                _ => {
+                    // TODO infer definitions in unpacking assignment
+                    self.infer_expression(&item.context_expr);
+                }
+            }
        }

        self.infer_body(body);
    }

+    fn infer_with_item_definition(
+        &mut self,
+        target: &ast::ExprName,
+        with_item: &ast::WithItem,
+        definition: Definition<'db>,
+    ) {
+        let expression = self.index.expression(&with_item.context_expr);
+        let result = infer_expression_types(self.db, expression);
+        self.extend(result);
+
+        // TODO(dhruvmanila): The correct type inference here is the return type of the __enter__
+        // method of the context manager.
+        let context_expr_ty = self
+            .types
+            .expression_ty(with_item.context_expr.scoped_ast_id(self.db, self.scope));
+
+        self.types
+            .expressions
+            .insert(target.scoped_ast_id(self.db, self.scope), context_expr_ty);
+        self.types.definitions.insert(definition, context_expr_ty);
+    }
+
    fn infer_match_statement(&mut self, match_statement: &ast::StmtMatch) {
        let ast::StmtMatch {
            range: _,
@@ -763,15 +809,35 @@ impl<'db> TypeInferenceBuilder<'db> {
    }

    fn infer_augmented_assignment_statement(&mut self, assignment: &ast::StmtAugAssign) {
-        // TODO this should be a Definition
+        if assignment.target.is_name_expr() {
+            self.infer_definition(assignment);
+        } else {
+            // TODO currently we don't consider assignments to non-Names to be Definitions
+            self.infer_augment_assignment(assignment);
+        }
+    }
+
+    fn infer_augment_assignment_definition(
+        &mut self,
+        assignment: &ast::StmtAugAssign,
+        definition: Definition<'db>,
+    ) {
+        let target_ty = self.infer_augment_assignment(assignment);
+        self.types.definitions.insert(definition, target_ty);
+    }
+
+    fn infer_augment_assignment(&mut self, assignment: &ast::StmtAugAssign) -> Type<'db> {
        let ast::StmtAugAssign {
            range: _,
            target,
            op: _,
            value,
        } = assignment;
-        self.infer_expression(target);
        self.infer_expression(value);
+        self.infer_expression(target);
+
+        // TODO(dhruvmanila): Resolve the target type using the value type and the operator
+        Type::Unknown
    }

    fn infer_type_alias_statement(&mut self, type_alias_statement: &ast::StmtTypeAlias) {
@@ -832,7 +898,26 @@ impl<'db> TypeInferenceBuilder<'db> {
            asname: _,
        } = alias;

-        let module_ty = self.module_ty_from_name(ModuleName::new(name));
+        let module_ty = ModuleName::new(name)
+            .ok_or(ModuleResolutionError::InvalidSyntax)
+            .and_then(|module_name| self.module_ty_from_name(module_name));
+
+        let module_ty = match module_ty {
+            Ok(ty) => ty,
+            Err(ModuleResolutionError::InvalidSyntax) => {
+                tracing::debug!("Failed to resolve import due to invalid syntax");
+                Type::Unknown
+            }
+            Err(ModuleResolutionError::UnresolvedModule) => {
+                self.add_diagnostic(
+                    AnyNodeRef::Alias(alias),
+                    "unresolved-import",
+                    format_args!("Import '{name}' could not be resolved."),
+                );
+                Type::Unknown
+            }
+        };
+
        self.types.definitions.insert(definition, module_ty);
    }

@@ -880,10 +965,18 @@ impl<'db> TypeInferenceBuilder<'db> {
    /// - `tail` is the relative module name stripped of all leading dots:
    ///   - `from .foo import bar` => `tail == "foo"`
    ///   - `from ..foo.bar import baz` => `tail == "foo.bar"`
-    fn relative_module_name(&self, tail: Option<&str>, level: NonZeroU32) -> Option<ModuleName> {
+    fn relative_module_name(
+        &self,
+        tail: Option<&str>,
+        level: NonZeroU32,
+    ) -> Result<ModuleName, ModuleResolutionError> {
        let Some(module) = file_to_module(self.db, self.file) else {
-            tracing::debug!("Failed to resolve file {:?} to a module", self.file);
-            return None;
+            tracing::debug!(
+                "Relative module resolution '{}' failed; could not resolve file '{}' to a module",
+                format_import_from_module(level.get(), tail),
+                self.file.path(self.db)
+            );
+            return Err(ModuleResolutionError::UnresolvedModule);
        };
        let mut level = level.get();
        if module.kind().is_package() {
@@ -891,17 +984,19 @@ impl<'db> TypeInferenceBuilder<'db> {
        }
        let mut module_name = module.name().to_owned();
        for _ in 0..level {
-            module_name = module_name.parent()?;
+            module_name = module_name
+                .parent()
+                .ok_or(ModuleResolutionError::UnresolvedModule)?;
        }
        if let Some(tail) = tail {
            if let Some(valid_tail) = ModuleName::new(tail) {
                module_name.extend(&valid_tail);
            } else {
-                tracing::debug!("Failed to resolve relative import due to invalid syntax");
-                return None;
+                tracing::debug!("Relative module resolution failed: invalid syntax");
+                return Err(ModuleResolutionError::InvalidSyntax);
            }
        }
-        Some(module_name)
+        Ok(module_name)
    }

    fn infer_import_from_definition(
@@ -921,16 +1016,27 @@ impl<'db> TypeInferenceBuilder<'db> {
        // `follow_nonexistent_import_bare_to_module()`.
        let ast::StmtImportFrom { module, level, .. } = import_from;
        tracing::trace!("Resolving imported object {alias:?} from statement {import_from:?}");
+        let module = module.as_deref();
        let module_name = if let Some(level) = NonZeroU32::new(*level) {
-            self.relative_module_name(module.as_deref(), level)
+            tracing::trace!(
+                "Resolving imported object '{}' from module '{}' relative to file '{}'",
+                alias.name,
+                format_import_from_module(level.get(), module),
+                self.file.path(self.db),
+            );
+            self.relative_module_name(module, level)
        } else {
-            let module_name = module
-                .as_ref()
-                .expect("Non-relative import should always have a non-None `module`!");
-            ModuleName::new(module_name)
+            tracing::trace!(
+                "Resolving imported object '{}' from module '{}'",
+                alias.name,
+                format_import_from_module(*level, module),
+            );
+            module
+                .and_then(ModuleName::new)
+                .ok_or(ModuleResolutionError::InvalidSyntax)
        };

-        let module_ty = self.module_ty_from_name(module_name);
+        let module_ty = module_name.and_then(|module_name| self.module_ty_from_name(module_name));

        let ast::Alias {
            range: _,
@@ -943,11 +1049,34 @@ impl<'db> TypeInferenceBuilder<'db> {
        // the runtime error will occur immediately (rather than when the symbol is *used*,
        // as would be the case for a symbol with type `Unbound`), so it's appropriate to
        // think of the type of the imported symbol as `Unknown` rather than `Unbound`
-        let ty = module_ty
+        let member_ty = module_ty
+            .unwrap_or(Type::Unbound)
            .member(self.db, &Name::new(&name.id))
            .replace_unbound_with(self.db, Type::Unknown);

-        self.types.definitions.insert(definition, ty);
+        if matches!(module_ty, Err(ModuleResolutionError::UnresolvedModule)) {
+            self.add_diagnostic(
+                AnyNodeRef::StmtImportFrom(import_from),
+                "unresolved-import",
+                format_args!(
+                    "Import '{}{}' could not be resolved.",
+                    ".".repeat(*level as usize),
+                    module.unwrap_or_default()
+                ),
+            );
+        } else if module_ty.is_ok() && member_ty.is_unknown() {
+            self.add_diagnostic(
+                AnyNodeRef::Alias(alias),
+                "unresolved-import",
+                format_args!(
+                    "Could not resolve import of '{name}' from '{}{}'",
+                    ".".repeat(*level as usize),
+                    module.unwrap_or_default()
+                ),
+            );
+        }
+
+        self.types.definitions.insert(definition, member_ty);
    }

    fn infer_return_statement(&mut self, ret: &ast::StmtReturn) {
@@ -961,10 +1090,13 @@ impl<'db> TypeInferenceBuilder<'db> {
        }
    }

-    fn module_ty_from_name(&self, module_name: Option<ModuleName>) -> Type<'db> {
-        module_name
-            .and_then(|module_name| resolve_module(self.db, module_name))
-            .map_or(Type::Unknown, |module| Type::Module(module.file()))
+    fn module_ty_from_name(
+        &self,
+        module_name: ModuleName,
+    ) -> Result<Type<'db>, ModuleResolutionError> {
+        resolve_module(self.db, module_name)
+            .map(|module| Type::Module(module.file()))
+            .ok_or(ModuleResolutionError::UnresolvedModule)
    }

    fn infer_decorator(&mut self, decorator: &ast::Decorator) -> Type<'db> {
@@ -1036,7 +1168,7 @@ impl<'db> TypeInferenceBuilder<'db> {
            ast::Expr::Yield(yield_expression) => self.infer_yield_expression(yield_expression),
            ast::Expr::YieldFrom(yield_from) => self.infer_yield_from_expression(yield_from),
            ast::Expr::Await(await_expression) => self.infer_await_expression(await_expression),
-            Expr::IpyEscapeCommand(_) => todo!("Implement Ipy escape command support"),
+            ast::Expr::IpyEscapeCommand(_) => todo!("Implement Ipy escape command support"),
        };

        let expr_id = expression.scoped_ast_id(self.db, self.scope);
@@ -1074,9 +1206,12 @@ impl<'db> TypeInferenceBuilder<'db> {
    }

    #[allow(clippy::unused_self)]
-    fn infer_bytes_literal_expression(&mut self, _literal: &ast::ExprBytesLiteral) -> Type<'db> {
-        // TODO
-        Type::Unknown
+    fn infer_bytes_literal_expression(&mut self, literal: &ast::ExprBytesLiteral) -> Type<'db> {
+        // TODO: ignoring r/R prefixes for now, should normalize bytes values
+        Type::BytesLiteral(BytesLiteralType::new(
+            self.db,
+            literal.value.bytes().collect(),
+        ))
    }

    fn infer_fstring_expression(&mut self, fstring: &ast::ExprFString) -> Type<'db> {
@@ -1094,21 +1229,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                        flags: _,
                    } = fstring;
                    for element in elements {
-                        match element {
-                            ast::FStringElement::Literal(_) => {
-                                // TODO string literal type
-                            }
-                            ast::FStringElement::Expression(expr_element) => {
-                                let ast::FStringExpressionElement {
-                                    range: _,
-                                    expression,
-                                    debug_text: _,
-                                    conversion: _,
-                                    format_spec: _,
-                                } = expr_element;
-                                self.infer_expression(expression);
-                            }
-                        }
+                        self.infer_fstring_element(element);
                    }
                }
            }
@@ -1118,6 +1239,30 @@ impl<'db> TypeInferenceBuilder<'db> {
        Type::Unknown
    }

+    fn infer_fstring_element(&mut self, element: &ast::FStringElement) {
+        match element {
+            ast::FStringElement::Literal(_) => {
+                // TODO string literal type
+            }
+            ast::FStringElement::Expression(expr_element) => {
+                let ast::FStringExpressionElement {
+                    range: _,
+                    expression,
+                    debug_text: _,
+                    conversion: _,
+                    format_spec,
+                } = expr_element;
+                self.infer_expression(expression);
+
+                if let Some(format_spec) = format_spec {
+                    for spec_element in &format_spec.elements {
+                        self.infer_fstring_element(spec_element);
+                    }
+                }
+            }
+        }
+    }
+
    #[allow(clippy::unused_self)]
    fn infer_ellipsis_literal_expression(
        &mut self,
@@ -1542,6 +1687,7 @@ impl<'db> TypeInferenceBuilder<'db> {
        let left_ty = self.infer_expression(left);
        let right_ty = self.infer_expression(right);

+        // TODO flatten the matches by matching on (left_ty, right_ty, op)
        match left_ty {
            Type::Any => Type::Any,
            Type::Unknown => Type::Unknown,
@@ -1580,6 +1726,22 @@ impl<'db> TypeInferenceBuilder<'db> {
                    _ => Type::Unknown, // TODO
                }
            }
+            Type::BytesLiteral(lhs) => {
+                match right_ty {
+                    Type::BytesLiteral(rhs) => {
+                        match op {
+                            ast::Operator::Add => Type::BytesLiteral(BytesLiteralType::new(
+                                self.db,
+                                [lhs.value(self.db).as_ref(), rhs.value(self.db).as_ref()]
+                                    .concat()
+                                    .into_boxed_slice(),
+                            )),
+                            _ => Type::Unknown, // TODO
+                        }
+                    }
+                    _ => Type::Unknown, // TODO
+                }
+            }
            _ => Type::Unknown, // TODO
        }
    }
@@ -1683,6 +1845,28 @@ impl<'db> TypeInferenceBuilder<'db> {
        }
    }

+    /// Adds a new diagnostic.
+    ///
+    /// The diagnostic does not get added if the rule isn't enabled for this file.
+    fn add_diagnostic(&mut self, node: AnyNodeRef, rule: &str, message: std::fmt::Arguments) {
+        if !self.db.is_file_open(self.file) {
+            return;
+        }
+
+        // TODO: Don't emit the diagnostic if:
+        // * The enclosing node contains any syntax errors
+        // * The rule is disabled for this file. We probably want to introduce a new query that
+        //   returns a rule selector for a given file that respects the package's settings,
+        //   any global pragma comments in the file, and any per-file-ignores.
+
+        self.types.diagnostics.push(TypeCheckDiagnostic {
+            file: self.file,
+            rule: rule.to_string(),
+            message: message.to_string(),
+            range: node.range(),
+        });
+    }
+
    pub(super) fn finish(mut self) -> TypeInference<'db> {
        self.infer_region();
        self.types.shrink_to_fit();
@@ -1690,6 +1874,20 @@ impl<'db> TypeInferenceBuilder<'db> {
    }
 }

+fn format_import_from_module(level: u32, module: Option<&str>) -> String {
+    format!(
+        "{}{}",
+        ".".repeat(level as usize),
+        module.unwrap_or_default()
+    )
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+enum ModuleResolutionError {
+    InvalidSyntax,
+    UnresolvedModule,
+}
+
 #[cfg(test)]
 mod tests {
    use anyhow::Context;
@@ -1720,14 +1918,9 @@ mod tests {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::default(),
-                search_paths: SearchPathSettings {
-                    extra_paths: Vec::new(),
-                    src_root,
-                    site_packages: vec![],
-                    custom_typeshed: None,
-                },
+                search_paths: SearchPathSettings::new(src_root),
            },
        )
        .expect("Valid search path settings");
@@ -1747,13 +1940,11 @@ mod tests {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::default(),
                search_paths: SearchPathSettings {
-                    extra_paths: Vec::new(),
-                    src_root,
-                    site_packages: vec![],
                    custom_typeshed: Some(SystemPathBuf::from(typeshed)),
+                    ..SearchPathSettings::new(src_root)
                },
            },
        )
@@ -1943,6 +2134,16 @@ mod tests {
        Ok(())
    }

+    #[test]
+    fn from_import_with_no_module_name() -> anyhow::Result<()> {
+        // This test checks that invalid syntax in a `StmtImportFrom` node
+        // leads to the type being inferred as `Unknown`
+        let mut db = setup_db();
+        db.write_file("src/foo.py", "from import bar")?;
+        assert_public_ty(&db, "src/foo.py", "bar", "Unknown");
+        Ok(())
+    }
+
    #[test]
    fn resolve_base_class_by_name() -> anyhow::Result<()> {
        let mut db = setup_db();
@@ -2054,6 +2255,28 @@ mod tests {
        Ok(())
    }

+    #[test]
+    fn bytes_type() -> anyhow::Result<()> {
+        let mut db = setup_db();
+
+        db.write_dedented(
+            "src/a.py",
+            "
+            w = b'red' b'knot'
+            x = b'hello'
+            y = b'world' + b'!'
+            z = b'\\xff\\x00'
+            ",
+        )?;
+
+        assert_public_ty(&db, "src/a.py", "w", "Literal[b\"redknot\"]");
+        assert_public_ty(&db, "src/a.py", "x", "Literal[b\"hello\"]");
+        assert_public_ty(&db, "src/a.py", "y", "Literal[b\"world!\"]");
+        assert_public_ty(&db, "src/a.py", "z", "Literal[b\"\\xff\\x00\"]");
+
+        Ok(())
+    }
+
    #[test]
    fn resolve_union() -> anyhow::Result<()> {
        let mut db = setup_db();
@@ -2109,6 +2332,23 @@ mod tests {
        Ok(())
    }

+    #[test]
+    fn walrus_self_plus_one() -> anyhow::Result<()> {
+        let mut db = setup_db();
+
+        db.write_dedented(
+            "src/a.py",
+            "
+            x = 0
+            (x := x + 1)
+            ",
+        )?;
+
+        assert_public_ty(&db, "src/a.py", "x", "Literal[1]");
+
+        Ok(())
+    }
+
    #[test]
    fn ifexpr() -> anyhow::Result<()> {
        let mut db = setup_db();
--- a/crates/red_knot_server/Cargo.toml
+++ b/crates/red_knot_server/Cargo.toml
@@ -11,10 +11,8 @@ repository = { workspace = true }
 license = { workspace = true }

 [dependencies]
-red_knot_python_semantic = { workspace = true }
 red_knot_workspace = { workspace = true }
 ruff_db = { workspace = true }
-ruff_linter = { workspace = true }
 ruff_notebook = { workspace = true }
 ruff_python_ast = { workspace = true }
 ruff_source_file = { workspace = true }
--- a/crates/red_knot_server/src/server.rs
+++ b/crates/red_knot_server/src/server.rs
@@ -3,11 +3,10 @@
 use std::num::NonZeroUsize;
 use std::panic::PanicInfo;

-use lsp_server as lsp;
-use lsp_types as types;
+use lsp_server::Message;
 use lsp_types::{
-    ClientCapabilities, DiagnosticOptions, NotebookCellSelector, NotebookDocumentSyncOptions,
-    NotebookSelector, TextDocumentSyncCapability, TextDocumentSyncOptions,
+    ClientCapabilities, DiagnosticOptions, DiagnosticServerCapabilities, MessageType,
+    ServerCapabilities, TextDocumentSyncCapability, TextDocumentSyncOptions, Url,
 };

 use self::connection::{Connection, ConnectionInitializer};
@@ -74,7 +73,7 @@ impl Server {
            init_params.client_info.as_ref(),
        );

-        let mut workspace_for_url = |url: lsp_types::Url| {
+        let mut workspace_for_url = |url: Url| {
            let Some(workspace_settings) = workspace_settings.as_mut() else {
                return (url, ClientSettings::default());
            };
@@ -93,7 +92,7 @@ impl Server {
            }).collect())
            .or_else(|| {
                tracing::warn!("No workspace(s) were provided during initialization. Using the current working directory as a default workspace...");
-                let uri = types::Url::from_file_path(std::env::current_dir().ok()?).ok()?;
+                let uri = Url::from_file_path(std::env::current_dir().ok()?).ok()?;
                Some(vec![workspace_for_url(uri)])
            })
            .ok_or_else(|| {
@@ -149,7 +148,7 @@ impl Server {
            try_show_message(
                "The Ruff language server exited with a panic. See the logs for more details."
                    .to_string(),
-                lsp_types::MessageType::ERROR,
+                MessageType::ERROR,
            )
            .ok();
        }));
@@ -182,9 +181,9 @@ impl Server {
                break;
            }
            let task = match msg {
-                lsp::Message::Request(req) => api::request(req),
-                lsp::Message::Notification(notification) => api::notification(notification),
-                lsp::Message::Response(response) => scheduler.response(response),
+                Message::Request(req) => api::request(req),
+                Message::Notification(notification) => api::notification(notification),
+                Message::Response(response) => scheduler.response(response),
            };
            scheduler.dispatch(task);
        }
@@ -206,24 +205,12 @@ impl Server {
            .unwrap_or_default()
    }

-    fn server_capabilities(position_encoding: PositionEncoding) -> types::ServerCapabilities {
-        types::ServerCapabilities {
+    fn server_capabilities(position_encoding: PositionEncoding) -> ServerCapabilities {
+        ServerCapabilities {
            position_encoding: Some(position_encoding.into()),
-            diagnostic_provider: Some(types::DiagnosticServerCapabilities::Options(
-                DiagnosticOptions {
-                    identifier: Some(crate::DIAGNOSTIC_NAME.into()),
-                    ..Default::default()
-                },
-            )),
-            notebook_document_sync: Some(types::OneOf::Left(NotebookDocumentSyncOptions {
-                save: Some(false),
-                notebook_selector: [NotebookSelector::ByCells {
-                    notebook: None,
-                    cells: vec![NotebookCellSelector {
-                        language: "python".to_string(),
-                    }],
-                }]
-                .to_vec(),
+            diagnostic_provider: Some(DiagnosticServerCapabilities::Options(DiagnosticOptions {
+                identifier: Some(crate::DIAGNOSTIC_NAME.into()),
+                ..Default::default()
            })),
            text_document_sync: Some(TextDocumentSyncCapability::Options(
                TextDocumentSyncOptions {
--- a/crates/red_knot_server/src/session.rs
+++ b/crates/red_knot_server/src/session.rs
@@ -8,7 +8,6 @@ use std::sync::Arc;
 use anyhow::anyhow;
 use lsp_types::{ClientCapabilities, Url};

-use red_knot_python_semantic::{ProgramSettings, PythonVersion, SearchPathSettings};
 use red_knot_workspace::db::RootDatabase;
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File};
@@ -67,19 +66,10 @@ impl Session {
                .ok_or_else(|| anyhow!("Workspace path is not a valid UTF-8 path: {:?}", path))?;
            let system = LSPSystem::new(index.clone());

-            let metadata = WorkspaceMetadata::from_path(system_path, &system)?;
            // TODO(dhruvmanila): Get the values from the client settings
-            let program_settings = ProgramSettings {
-                target_version: PythonVersion::default(),
-                search_paths: SearchPathSettings {
-                    extra_paths: vec![],
-                    src_root: system_path.to_path_buf(),
-                    site_packages: vec![],
-                    custom_typeshed: None,
-                },
-            };
+            let metadata = WorkspaceMetadata::from_path(system_path, &system, None)?;
            // TODO(micha): Handle the case where the program settings are incorrect more gracefully.
-            workspaces.insert(path, RootDatabase::new(metadata, program_settings, system)?);
+            workspaces.insert(path, RootDatabase::new(metadata, system)?);
        }

        Ok(Self {
--- a/crates/red_knot_server/src/session/capabilities.rs
+++ b/crates/red_knot_server/src/session/capabilities.rs
@@ -1,5 +1,4 @@
 use lsp_types::ClientCapabilities;
-use ruff_linter::display_settings;

 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 #[allow(clippy::struct_excessive_bools)]
@@ -66,20 +65,3 @@ impl ResolvedClientCapabilities {
        }
    }
 }
-
-impl std::fmt::Display for ResolvedClientCapabilities {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        display_settings! {
-            formatter = f,
-            namespace = "capabilities",
-            fields = [
-                self.code_action_deferred_edit_resolution,
-                self.apply_edit,
-                self.document_changes,
-                self.workspace_refresh,
-                self.pull_diagnostics,
-            ]
-        };
-        Ok(())
-    }
-}
--- a/crates/red_knot_server/src/session/index.rs
+++ b/crates/red_knot_server/src/session/index.rs
@@ -278,18 +278,6 @@ impl DocumentQuery {
        }
    }

-    /// Generate a source kind used by the linter.
-    pub(crate) fn make_source_kind(&self) -> ruff_linter::source_kind::SourceKind {
-        match self {
-            Self::Text { document, .. } => {
-                ruff_linter::source_kind::SourceKind::Python(document.contents().to_string())
-            }
-            Self::Notebook { notebook, .. } => {
-                ruff_linter::source_kind::SourceKind::IpyNotebook(notebook.make_ruff_notebook())
-            }
-        }
-    }
-
    /// Attempts to access the underlying notebook document that this query is selecting.
    pub fn as_notebook(&self) -> Option<&NotebookDocument> {
        match self {
--- a/crates/red_knot_wasm/src/lib.rs
+++ b/crates/red_knot_wasm/src/lib.rs
@@ -3,8 +3,8 @@ use std::any::Any;
 use js_sys::Error;
 use wasm_bindgen::prelude::*;

-use red_knot_python_semantic::{ProgramSettings, SearchPathSettings};
 use red_knot_workspace::db::RootDatabase;
+use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File};
 use ruff_db::system::walk_directory::WalkDirectoryBuilder;
@@ -41,16 +41,17 @@ impl Workspace {
    #[wasm_bindgen(constructor)]
    pub fn new(root: &str, settings: &Settings) -> Result<Workspace, Error> {
        let system = WasmSystem::new(SystemPath::new(root));
-        let workspace =
-            WorkspaceMetadata::from_path(SystemPath::new(root), &system).map_err(into_error)?;
+        let workspace = WorkspaceMetadata::from_path(
+            SystemPath::new(root),
+            &system,
+            Some(Configuration {
+                target_version: Some(settings.target_version.into()),
+                ..Configuration::default()
+            }),
+        )
+        .map_err(into_error)?;

-        let program_settings = ProgramSettings {
-            target_version: settings.target_version.into(),
-            search_paths: SearchPathSettings::default(),
-        };
-
-        let db =
-            RootDatabase::new(workspace, program_settings, system.clone()).map_err(into_error)?;
+        let db = RootDatabase::new(workspace, system.clone()).map_err(into_error)?;

        Ok(Self { db, system })
    }
@@ -109,7 +110,7 @@ impl Workspace {
    pub fn check_file(&self, file_id: &FileHandle) -> Result<Vec<String>, Error> {
        let result = self.db.check_file(file_id.file).map_err(into_error)?;

-        Ok(result.to_vec())
+        Ok(result.clone())
    }

    /// Checks all open files
--- a/crates/red_knot_wasm/tests/api.rs
+++ b/crates/red_knot_wasm/tests/api.rs
@@ -17,5 +17,8 @@ fn check() {

    let result = workspace.check_file(&test).expect("Check to succeed");

-    assert_eq!(result, vec!["/test.py:1:8: Unresolved import 'random22'"]);
+    assert_eq!(
+        result,
+        vec!["/test.py:1:8: Import 'random22' could not be resolved.",]
+    );
 }
--- a/crates/red_knot_workspace/Cargo.toml
+++ b/crates/red_knot_workspace/Cargo.toml
@@ -24,10 +24,10 @@ crossbeam = { workspace = true }
 notify = { workspace = true }
 rustc-hash = { workspace = true }
 salsa = { workspace = true }
-thiserror = { workspace = true }
 tracing = { workspace = true }

 [dev-dependencies]
+ruff_db = { workspace = true, features = ["testing"]}

 [lints]
 workspace = true
--- a/crates/red_knot_workspace/resources/test/corpus/04_assign_named_expr.py
+++ b/crates/red_knot_workspace/resources/test/corpus/04_assign_named_expr.py
@@ -0,0 +1,2 @@
+x = 0
+(x := x + 1)
--- a/crates/red_knot_workspace/resources/test/corpus/10_if_with_named_expr.py
+++ b/crates/red_knot_workspace/resources/test/corpus/10_if_with_named_expr.py
@@ -0,0 +1,3 @@
+x = 0
+if x := x + 1:
+    pass
--- a/crates/red_knot_workspace/resources/test/corpus/85_match_guard_with_named_expr.py
+++ b/crates/red_knot_workspace/resources/test/corpus/85_match_guard_with_named_expr.py
@@ -0,0 +1,3 @@
+match x:
+    case [1, 0] if x := x[:0]:
+        y = 1
--- a/crates/red_knot_workspace/src/db.rs
+++ b/crates/red_knot_workspace/src/db.rs
@@ -1,17 +1,15 @@
 use std::panic::RefUnwindSafe;
 use std::sync::Arc;

-use red_knot_python_semantic::{
-    vendored_typeshed_stubs, Db as SemanticDb, Program, ProgramSettings,
-};
+use salsa::plumbing::ZalsaDatabase;
+use salsa::{Cancelled, Event};
+
+use red_knot_python_semantic::{vendored_typeshed_stubs, Db as SemanticDb, Program};
 use ruff_db::files::{File, Files};
 use ruff_db::system::System;
 use ruff_db::vendored::VendoredFileSystem;
 use ruff_db::{Db as SourceDb, Upcast};
-use salsa::plumbing::ZalsaDatabase;
-use salsa::{Cancelled, Event};

-use crate::lint::Diagnostics;
 use crate::workspace::{check_file, Workspace, WorkspaceMetadata};

 mod changes;
@@ -28,11 +26,7 @@ pub struct RootDatabase {
 }

 impl RootDatabase {
-    pub fn new<S>(
-        workspace: WorkspaceMetadata,
-        settings: ProgramSettings,
-        system: S,
-    ) -> anyhow::Result<Self>
+    pub fn new<S>(workspace: WorkspaceMetadata, system: S) -> anyhow::Result<Self>
    where
        S: System + 'static + Send + Sync + RefUnwindSafe,
    {
@@ -43,11 +37,11 @@ impl RootDatabase {
            system: Arc::new(system),
        };

-        let workspace = Workspace::from_metadata(&db, workspace);
        // Initialize the `Program` singleton
-        Program::from_settings(&db, settings)?;
+        Program::from_settings(&db, workspace.settings().program())?;
+
+        db.workspace = Some(Workspace::from_metadata(&db, workspace));

-        db.workspace = Some(workspace);
        Ok(db)
    }

@@ -61,7 +55,7 @@ impl RootDatabase {
        self.with_db(|db| db.workspace().check(db))
    }

-    pub fn check_file(&self, file: File) -> Result<Diagnostics, Cancelled> {
+    pub fn check_file(&self, file: File) -> Result<Vec<String>, Cancelled> {
        self.with_db(|db| check_file(db, file))
    }

@@ -115,7 +109,15 @@ impl Upcast<dyn SourceDb> for RootDatabase {
 }

 #[salsa::db]
-impl SemanticDb for RootDatabase {}
+impl SemanticDb for RootDatabase {
+    fn is_file_open(&self, file: File) -> bool {
+        let Some(workspace) = &self.workspace else {
+            return false;
+        };
+
+        workspace.is_file_open(self, file)
+    }
+}

 #[salsa::db]
 impl SourceDb for RootDatabase {
@@ -153,9 +155,10 @@ impl Db for RootDatabase {}

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

+    use salsa::Event;
+
    use red_knot_python_semantic::{vendored_typeshed_stubs, Db as SemanticDb};
    use ruff_db::files::Files;
    use ruff_db::system::{DbWithTestSystem, System, TestSystem};
@@ -242,7 +245,12 @@ pub(crate) mod tests {
    }

    #[salsa::db]
-    impl red_knot_python_semantic::Db for TestDb {}
+    impl red_knot_python_semantic::Db for TestDb {
+        fn is_file_open(&self, file: ruff_db::files::File) -> bool {
+            !file.path(self).is_vendored_path()
+        }
+    }
+
    #[salsa::db]
    impl Db for TestDb {}

--- a/crates/red_knot_workspace/src/db/changes.rs
+++ b/crates/red_knot_workspace/src/db/changes.rs
@@ -1,22 +1,33 @@
-use rustc_hash::FxHashSet;
-
+use red_knot_python_semantic::Program;
 use ruff_db::files::{system_path_to_file, File, Files};
 use ruff_db::system::walk_directory::WalkState;
 use ruff_db::system::SystemPath;
 use ruff_db::Db;
+use rustc_hash::FxHashSet;

 use crate::db::RootDatabase;
 use crate::watch;
 use crate::watch::{CreatedKind, DeletedKind};
+use crate::workspace::settings::Configuration;
 use crate::workspace::WorkspaceMetadata;

 impl RootDatabase {
-    #[tracing::instrument(level = "debug", skip(self, changes))]
-    pub fn apply_changes(&mut self, changes: Vec<watch::ChangeEvent>) {
+    #[tracing::instrument(level = "debug", skip(self, changes, base_configuration))]
+    pub fn apply_changes(
+        &mut self,
+        changes: Vec<watch::ChangeEvent>,
+        base_configuration: Option<&Configuration>,
+    ) {
        let workspace = self.workspace();
        let workspace_path = workspace.root(self).to_path_buf();
+        let program = Program::get(self);
+        let custom_stdlib_versions_path = program
+            .custom_stdlib_search_path(self)
+            .map(|path| path.join("VERSIONS"));

        let mut workspace_change = false;
+        // Changes to a custom stdlib path's VERSIONS
+        let mut custom_stdlib_change = false;
        // Packages that need reloading
        let mut changed_packages = FxHashSet::default();
        // Paths that were added
@@ -54,6 +65,10 @@ impl RootDatabase {

                    continue;
                }
+
+                if Some(path) == custom_stdlib_versions_path.as_deref() {
+                    custom_stdlib_change = true;
+                }
            }

            match change {
@@ -100,7 +115,13 @@ impl RootDatabase {
                    } else {
                        sync_recursively(self, &path);

-                        // TODO: Remove after converting `package.files()` to a salsa query.
+                        if custom_stdlib_versions_path
+                            .as_ref()
+                            .is_some_and(|versions_path| versions_path.starts_with(&path))
+                        {
+                            custom_stdlib_change = true;
+                        }
+
                        if let Some(package) = workspace.package(self, &path) {
                            changed_packages.insert(package);
                        } else {
@@ -118,9 +139,13 @@ impl RootDatabase {
        }

        if workspace_change {
-            match WorkspaceMetadata::from_path(&workspace_path, self.system()) {
+            match WorkspaceMetadata::from_path(
+                &workspace_path,
+                self.system(),
+                base_configuration.cloned(),
+            ) {
                Ok(metadata) => {
-                    tracing::debug!("Reload workspace after structural change.");
+                    tracing::debug!("Reloading workspace after structural change.");
                    // TODO: Handle changes in the program settings.
                    workspace.reload(self, metadata);
                }
@@ -130,6 +155,11 @@ impl RootDatabase {
            }

            return;
+        } else if custom_stdlib_change {
+            let search_paths = workspace.search_path_settings(self).clone();
+            if let Err(error) = program.update_search_paths(self, &search_paths) {
+                tracing::error!("Failed to set the new search paths: {error}");
+            }
        }

        let mut added_paths = added_paths.into_iter().filter(|path| {
--- a/crates/red_knot_workspace/src/lib.rs
+++ b/crates/red_knot_workspace/src/lib.rs
@@ -1,5 +1,4 @@
 pub mod db;
 pub mod lint;
-pub mod site_packages;
 pub mod watch;
 pub mod workspace;
--- a/crates/red_knot_workspace/src/lint.rs
+++ b/crates/red_knot_workspace/src/lint.rs
@@ -1,5 +1,4 @@
 use std::cell::RefCell;
-use std::ops::Deref;
 use std::time::Duration;

 use tracing::debug_span;
@@ -8,7 +7,7 @@ use red_knot_python_semantic::types::Type;
 use red_knot_python_semantic::{HasTy, ModuleName, SemanticModel};
 use ruff_db::files::File;
 use ruff_db::parsed::{parsed_module, ParsedModule};
-use ruff_db::source::{line_index, source_text, SourceText};
+use ruff_db::source::{source_text, SourceText};
 use ruff_python_ast as ast;
 use ruff_python_ast::visitor::{walk_expr, walk_stmt, Visitor};
 use ruff_text_size::{Ranged, TextSize};
@@ -22,7 +21,7 @@ use crate::db::Db;
 pub(crate) fn unwind_if_cancelled(db: &dyn Db) {}

 #[salsa::tracked(return_ref)]
-pub(crate) fn lint_syntax(db: &dyn Db, file_id: File) -> Diagnostics {
+pub(crate) fn lint_syntax(db: &dyn Db, file_id: File) -> Vec<String> {
    #[allow(clippy::print_stdout)]
    if std::env::var("RED_KNOT_SLOW_LINT").is_ok() {
        for i in 0..10 {
@@ -49,22 +48,9 @@ pub(crate) fn lint_syntax(db: &dyn Db, file_id: File) -> Diagnostics {
        };
        visitor.visit_body(&ast.body);
        diagnostics = visitor.diagnostics;
-    } else {
-        let path = file_id.path(db);
-        let line_index = line_index(db.upcast(), file_id);
-        diagnostics.extend(parsed.errors().iter().map(|err| {
-            let source_location = line_index.source_location(err.location.start(), source.as_str());
-            format!(
-                "{}:{}:{}: {}",
-                path.as_str(),
-                source_location.row,
-                source_location.column,
-                err,
-            )
-        }));
    }

-    Diagnostics::from(diagnostics)
+    diagnostics
 }

 fn lint_lines(source: &str, diagnostics: &mut Vec<String>) {
@@ -86,7 +72,7 @@ fn lint_lines(source: &str, diagnostics: &mut Vec<String>) {

 #[allow(unreachable_pub)]
 #[salsa::tracked(return_ref)]
-pub fn lint_semantic(db: &dyn Db, file_id: File) -> Diagnostics {
+pub fn lint_semantic(db: &dyn Db, file_id: File) -> Vec<String> {
    let _span = debug_span!("lint_semantic", file=%file_id.path(db)).entered();

    let source = source_text(db.upcast(), file_id);
@@ -94,7 +80,7 @@ pub fn lint_semantic(db: &dyn Db, file_id: File) -> Diagnostics {
    let semantic = SemanticModel::new(db.upcast(), file_id);

    if !parsed.is_valid() {
-        return Diagnostics::Empty;
+        return vec![];
    }

    let context = SemanticLintContext {
@@ -106,7 +92,7 @@ pub fn lint_semantic(db: &dyn Db, file_id: File) -> Diagnostics {

    SemanticVisitor { context: &context }.visit_body(parsed.suite());

-    Diagnostics::from(context.diagnostics.take())
+    context.diagnostics.take()
 }

 fn format_diagnostic(context: &SemanticLintContext, message: &str, start: TextSize) -> String {
@@ -116,48 +102,13 @@ fn format_diagnostic(context: &SemanticLintContext, message: &str, start: TextSi
        .source_location(start, context.source_text());
    format!(
        "{}:{}:{}: {}",
-        context.semantic.file_path().as_str(),
+        context.semantic.file_path(),
        source_location.row,
        source_location.column,
        message,
    )
 }

-fn lint_unresolved_imports(context: &SemanticLintContext, import: AnyImportRef) {
-    // TODO: this treats any symbol with `Type::Unknown` as an unresolved import,
-    // which isn't really correct: if it exists but has `Type::Unknown` in the
-    // module we're importing it from, we shouldn't really emit a diagnostic here,
-    // but currently do.
-    match import {
-        AnyImportRef::Import(import) => {
-            for alias in &import.names {
-                let ty = alias.ty(&context.semantic);
-
-                if ty.is_unknown() {
-                    context.push_diagnostic(format_diagnostic(
-                        context,
-                        &format!("Unresolved import '{}'", &alias.name),
-                        alias.start(),
-                    ));
-                }
-            }
-        }
-        AnyImportRef::ImportFrom(import) => {
-            for alias in &import.names {
-                let ty = alias.ty(&context.semantic);
-
-                if ty.is_unknown() {
-                    context.push_diagnostic(format_diagnostic(
-                        context,
-                        &format!("Unresolved import '{}'", &alias.name),
-                        alias.start(),
-                    ));
-                }
-            }
-        }
-    }
-}
-
 fn lint_maybe_undefined(context: &SemanticLintContext, name: &ast::ExprName) {
    if !matches!(name.ctx, ast::ExprContext::Load) {
        return;
@@ -280,17 +231,8 @@ struct SemanticVisitor<'a> {

 impl Visitor<'_> for SemanticVisitor<'_> {
    fn visit_stmt(&mut self, stmt: &ast::Stmt) {
-        match stmt {
-            ast::Stmt::ClassDef(class) => {
-                lint_bad_override(self.context, class);
-            }
-            ast::Stmt::Import(import) => {
-                lint_unresolved_imports(self.context, AnyImportRef::Import(import));
-            }
-            ast::Stmt::ImportFrom(import) => {
-                lint_unresolved_imports(self.context, AnyImportRef::ImportFrom(import));
-            }
-            _ => {}
+        if let ast::Stmt::ClassDef(class) = stmt {
+            lint_bad_override(self.context, class);
        }

        walk_stmt(self, stmt);
@@ -308,53 +250,6 @@ impl Visitor<'_> for SemanticVisitor<'_> {
    }
 }

-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Diagnostics {
-    Empty,
-    List(Vec<String>),
-}
-
-impl Diagnostics {
-    pub fn as_slice(&self) -> &[String] {
-        match self {
-            Diagnostics::Empty => &[],
-            Diagnostics::List(list) => list.as_slice(),
-        }
-    }
-}
-
-impl Deref for Diagnostics {
-    type Target = [String];
-    fn deref(&self) -> &Self::Target {
-        self.as_slice()
-    }
-}
-
-impl From<Vec<String>> for Diagnostics {
-    fn from(value: Vec<String>) -> Self {
-        if value.is_empty() {
-            Diagnostics::Empty
-        } else {
-            Diagnostics::List(value)
-        }
-    }
-}
-
-#[derive(Copy, Clone, Debug)]
-enum AnyImportRef<'a> {
-    Import(&'a ast::StmtImport),
-    ImportFrom(&'a ast::StmtImportFrom),
-}
-
-impl Ranged for AnyImportRef<'_> {
-    fn range(&self) -> ruff_text_size::TextRange {
-        match self {
-            AnyImportRef::Import(import) => import.range(),
-            AnyImportRef::ImportFrom(import) => import.range(),
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
    use red_knot_python_semantic::{Program, ProgramSettings, PythonVersion, SearchPathSettings};
@@ -363,7 +258,7 @@ mod tests {

    use crate::db::tests::TestDb;

-    use super::{lint_semantic, Diagnostics};
+    use super::lint_semantic;

    fn setup_db() -> TestDb {
        setup_db_with_root(SystemPathBuf::from("/src"))
@@ -378,14 +273,9 @@ mod tests {

        Program::from_settings(
            &db,
-            ProgramSettings {
+            &ProgramSettings {
                target_version: PythonVersion::default(),
-                search_paths: SearchPathSettings {
-                    extra_paths: Vec::new(),
-                    src_root,
-                    site_packages: vec![],
-                    custom_typeshed: None,
-                },
+                search_paths: SearchPathSettings::new(src_root),
            },
        )
        .expect("Valid program settings");
@@ -409,9 +299,9 @@ mod tests {
        .unwrap();

        let file = system_path_to_file(&db, "/src/a.py").expect("file to exist");
-        let Diagnostics::List(messages) = lint_semantic(&db, file) else {
-            panic!("expected some diagnostics");
-        };
+        let messages = lint_semantic(&db, file);
+
+        assert_ne!(messages, &[] as &[String], "expected some diagnostics");

        assert_eq!(
            *messages,
--- a/crates/red_knot_workspace/src/watch/watcher.rs
+++ b/crates/red_knot_workspace/src/watch/watcher.rs
@@ -109,7 +109,7 @@ struct WatcherInner {
 impl Watcher {
    /// Sets up file watching for `path`.
    pub fn watch(&mut self, path: &SystemPath) -> notify::Result<()> {
-        tracing::debug!("Watching path: {path}.");
+        tracing::debug!("Watching path: '{path}'.");

        self.inner_mut()
            .watcher
@@ -118,7 +118,7 @@ impl Watcher {

    /// Stops file watching for `path`.
    pub fn unwatch(&mut self, path: &SystemPath) -> notify::Result<()> {
-        tracing::debug!("Unwatching path: {path}.");
+        tracing::debug!("Unwatching path: '{path}'.");

        self.inner_mut().watcher.unwatch(path.as_std_path())
    }
@@ -351,7 +351,7 @@ impl Debouncer {
            }

            EventKind::Any => {
-                tracing::debug!("Skip any FS event for {path}.");
+                tracing::debug!("Skipping any FS event for '{path}'.");
                return;
            }
        };
--- a/crates/red_knot_workspace/src/workspace.rs
+++ b/crates/red_knot_workspace/src/workspace.rs
@@ -4,21 +4,26 @@ use rustc_hash::{FxBuildHasher, FxHashSet};
 use salsa::{Durability, Setter as _};

 pub use metadata::{PackageMetadata, WorkspaceMetadata};
-use ruff_db::source::{source_text, SourceDiagnostic};
+use red_knot_python_semantic::types::check_types;
+use red_knot_python_semantic::SearchPathSettings;
+use ruff_db::parsed::parsed_module;
+use ruff_db::source::{line_index, source_text, SourceDiagnostic};
 use ruff_db::{
    files::{system_path_to_file, File},
    system::{walk_directory::WalkState, SystemPath, SystemPathBuf},
 };
 use ruff_python_ast::{name::Name, PySourceType};
+use ruff_text_size::Ranged;

-use crate::workspace::files::{Index, IndexedFiles, PackageFiles};
+use crate::workspace::files::{Index, Indexed, PackageFiles};
 use crate::{
    db::Db,
-    lint::{lint_semantic, lint_syntax, Diagnostics},
+    lint::{lint_semantic, lint_syntax},
 };

 mod files;
 mod metadata;
+pub mod settings;

 /// The project workspace as a Salsa ingredient.
 ///
@@ -79,6 +84,10 @@ pub struct Workspace {
    /// The (first-party) packages in this workspace.
    #[return_ref]
    package_tree: BTreeMap<SystemPathBuf, Package>,
+
+    /// The unresolved search path configuration.
+    #[return_ref]
+    pub search_path_settings: SearchPathSettings,
 }

 /// A first-party package in a workspace.
@@ -92,8 +101,8 @@ pub struct Package {
    root_buf: SystemPathBuf,

    /// The files that are part of this package.
-    #[return_ref]
    #[default]
+    #[return_ref]
    file_set: PackageFiles,
    // TODO: Add the loaded settings.
 }
@@ -107,10 +116,14 @@ impl Workspace {
            packages.insert(package.root.clone(), Package::from_metadata(db, package));
        }

-        Workspace::builder(metadata.root, packages)
-            .durability(Durability::MEDIUM)
-            .open_fileset_durability(Durability::LOW)
-            .new(db)
+        Workspace::builder(
+            metadata.root,
+            packages,
+            metadata.settings.program.search_paths,
+        )
+        .durability(Durability::MEDIUM)
+        .open_fileset_durability(Durability::LOW)
+        .new(db)
    }

    pub fn root(self, db: &dyn Db) -> &SystemPath {
@@ -141,9 +154,12 @@ impl Workspace {
            new_packages.insert(path, package);
        }

-        self.set_package_tree(db)
-            .with_durability(Durability::MEDIUM)
-            .to(new_packages);
+        if &metadata.settings.program.search_paths != self.search_path_settings(db) {
+            self.set_search_path_settings(db)
+                .to(metadata.settings.program.search_paths);
+        }
+
+        self.set_package_tree(db).to(new_packages);
    }

    pub fn update_package(self, db: &mut dyn Db, metadata: PackageMetadata) -> anyhow::Result<()> {
@@ -197,7 +213,7 @@ impl Workspace {
    ///
    /// This changes the behavior of `check` to only check the open files rather than all files in the workspace.
    pub fn open_file(self, db: &mut dyn Db, file: File) {
-        tracing::debug!("Opening file {}", file.path(db));
+        tracing::debug!("Opening file '{}'", file.path(db));

        let mut open_files = self.take_open_files(db);
        open_files.insert(file);
@@ -206,7 +222,7 @@ impl Workspace {

    /// Closes a file in the workspace.
    pub fn close_file(self, db: &mut dyn Db, file: File) -> bool {
-        tracing::debug!("Closing file {}", file.path(db));
+        tracing::debug!("Closing file '{}'", file.path(db));

        let mut open_files = self.take_open_files(db);
        let removed = open_files.remove(&file);
@@ -249,6 +265,23 @@ impl Workspace {
            FxHashSet::default()
        }
    }
+
+    /// Returns `true` if the file is open in the workspace.
+    ///
+    /// A file is considered open when:
+    /// * explicitly set as an open file using [`open_file`](Self::open_file)
+    /// * It has a [`SystemPath`] and belongs to a package's `src` files
+    /// * It has a [`SystemVirtualPath`](ruff_db::system::SystemVirtualPath)
+    pub fn is_file_open(self, db: &dyn Db, file: File) -> bool {
+        if let Some(open_files) = self.open_files(db) {
+            open_files.contains(&file)
+        } else if let Some(system_path) = file.path(db).as_system_path() {
+            self.package(db, system_path)
+                .map_or(false, |package| package.contains_file(db, file))
+        } else {
+            file.path(db).is_system_virtual_path()
+        }
+    }
 }

 #[salsa::tracked]
@@ -259,13 +292,13 @@ impl Package {

    /// Returns `true` if `file` is a first-party file part of this package.
    pub fn contains_file(self, db: &dyn Db, file: File) -> bool {
-        self.files(db).read().contains(&file)
+        self.files(db).contains(&file)
    }

    #[tracing::instrument(level = "debug", skip(db))]
    pub fn remove_file(self, db: &mut dyn Db, file: File) {
        tracing::debug!(
-            "Remove file {} from package {}",
+            "Removing file '{}' from package '{}'",
            file.path(db),
            self.name(db)
        );
@@ -278,7 +311,11 @@ impl Package {
    }

    pub fn add_file(self, db: &mut dyn Db, file: File) {
-        tracing::debug!("Add file {} to package {}", file.path(db), self.name(db));
+        tracing::debug!(
+            "Adding file '{}' to package '{}'",
+            file.path(db),
+            self.name(db)
+        );

        let Some(mut index) = PackageFiles::indexed_mut(db, self) else {
            return;
@@ -289,10 +326,10 @@ impl Package {

    #[tracing::instrument(level = "debug", skip(db))]
    pub(crate) fn check(self, db: &dyn Db) -> Vec<String> {
-        tracing::debug!("Checking package {}", self.root(db));
+        tracing::debug!("Checking package '{}'", self.root(db));

        let mut result = Vec::new();
-        for file in &self.files(db).read() {
+        for file in &self.files(db) {
            let diagnostics = check_file(db, file);
            result.extend_from_slice(&diagnostics);
        }
@@ -301,15 +338,16 @@ impl Package {
    }

    /// Returns the files belonging to this package.
-    #[salsa::tracked]
-    pub fn files(self, db: &dyn Db) -> IndexedFiles {
-        let _entered = tracing::debug_span!("files").entered();
+    pub fn files(self, db: &dyn Db) -> Indexed<'_> {
        let files = self.file_set(db);

        let indexed = match files.get() {
            Index::Lazy(vacant) => {
-                tracing::debug!("Indexing files for package {}", self.name(db));
+                let _entered =
+                    tracing::debug_span!("index_package_files", package = %self.name(db)).entered();
+
                let files = discover_package_files(db, self.root(db));
+                tracing::info!("Found {} files in package '{}'", files.len(), self.name(db));
                vacant.set(files)
            }
            Index::Indexed(indexed) => indexed,
@@ -330,14 +368,12 @@ impl Package {
        assert_eq!(root, metadata.root());

        if self.name(db) != metadata.name() {
-            self.set_name(db)
-                .with_durability(Durability::MEDIUM)
-                .to(metadata.name);
+            self.set_name(db).to(metadata.name);
        }
    }

    pub fn reload_files(self, db: &mut dyn Db) {
-        tracing::debug!("Reload files for package {}", self.name(db));
+        tracing::debug!("Reloading files for package '{}'", self.name(db));

        if !self.file_set(db).is_lazy() {
            // Force a re-index of the files in the next revision.
@@ -347,10 +383,10 @@ impl Package {
 }

 #[salsa::tracked]
-pub(super) fn check_file(db: &dyn Db, file: File) -> Diagnostics {
+pub(super) fn check_file(db: &dyn Db, file: File) -> Vec<String> {
    let path = file.path(db);
    let _span = tracing::debug_span!("check_file", file=%path).entered();
-    tracing::debug!("Checking file {path}");
+    tracing::debug!("Checking file '{path}'");

    let mut diagnostics = Vec::new();

@@ -363,13 +399,36 @@ pub(super) fn check_file(db: &dyn Db, file: File) -> Diagnostics {
    );

    // Abort checking if there are IO errors.
-    if source_text(db.upcast(), file).has_read_error() {
-        return Diagnostics::from(diagnostics);
+    let source = source_text(db.upcast(), file);
+
+    if source.has_read_error() {
+        return diagnostics;
+    }
+
+    let parsed = parsed_module(db.upcast(), file);
+
+    if !parsed.errors().is_empty() {
+        let path = file.path(db);
+        let line_index = line_index(db.upcast(), file);
+        diagnostics.extend(parsed.errors().iter().map(|err| {
+            let source_location = line_index.source_location(err.location.start(), source.as_str());
+            format!("{path}:{source_location}: {message}", message = err.error)
+        }));
+    }
+
+    for diagnostic in check_types(db.upcast(), file) {
+        let index = line_index(db.upcast(), diagnostic.file());
+        let location = index.source_location(diagnostic.start(), source.as_str());
+        diagnostics.push(format!(
+            "{path}:{location}: {message}",
+            path = file.path(db),
+            message = diagnostic.message()
+        ));
    }

    diagnostics.extend_from_slice(lint_syntax(db, file));
    diagnostics.extend_from_slice(lint_semantic(db, file));
-    Diagnostics::from(diagnostics)
+    diagnostics
 }

 fn discover_package_files(db: &dyn Db, path: &SystemPath) -> FxHashSet<File> {
@@ -423,7 +482,7 @@ mod tests {
    use ruff_db::testing::assert_function_query_was_not_run;

    use crate::db::tests::TestDb;
-    use crate::lint::{lint_syntax, Diagnostics};
+    use crate::lint::lint_syntax;
    use crate::workspace::check_file;

    #[test]
@@ -441,9 +500,7 @@ mod tests {
        assert_eq!(source_text(&db, file).as_str(), "");
        assert_eq!(
            check_file(&db, file),
-            Diagnostics::List(vec![
-                "Failed to read file: No such file or directory".to_string()
-            ])
+            vec!["Failed to read file: No such file or directory".to_string()]
        );

        let events = db.take_salsa_events();
@@ -454,7 +511,7 @@ mod tests {
        db.write_file(path, "").unwrap();

        assert_eq!(source_text(&db, file).as_str(), "");
-        assert_eq!(check_file(&db, file), Diagnostics::Empty);
+        assert_eq!(check_file(&db, file), vec![] as Vec<String>);

        Ok(())
    }
--- a/crates/red_knot_workspace/src/workspace/files.rs
+++ b/crates/red_knot_workspace/src/workspace/files.rs
@@ -1,4 +1,4 @@
-use std::iter::FusedIterator;
+use std::marker::PhantomData;
 use std::ops::Deref;
 use std::sync::Arc;

@@ -10,6 +10,9 @@ use ruff_db::files::File;
 use crate::db::Db;
 use crate::workspace::Package;

+/// Cheap cloneable hash set of files.
+type FileSet = Arc<FxHashSet<File>>;
+
 /// The indexed files of a package.
 ///
 /// The indexing happens lazily, but the files are then cached for subsequent reads.
@@ -18,7 +21,7 @@ use crate::workspace::Package;
 /// The implementation uses internal mutability to transition between the lazy and indexed state
 /// without triggering a new salsa revision. This is safe because the initial indexing happens on first access,
 /// so no query can be depending on the contents of the indexed files before that. All subsequent mutations to
-/// the indexed files must go through `IndexedFilesMut`, which uses the Salsa setter `package.set_file_set` to
+/// the indexed files must go through `IndexedMut`, which uses the Salsa setter `package.set_file_set` to
 /// ensure that Salsa always knows when the set of indexed files have changed.
 #[derive(Debug)]
 pub struct PackageFiles {
@@ -32,46 +35,67 @@ impl PackageFiles {
        }
    }

-    fn indexed(indexed_files: IndexedFiles) -> Self {
+    fn indexed(files: FileSet) -> Self {
        Self {
-            state: std::sync::Mutex::new(State::Indexed(indexed_files)),
+            state: std::sync::Mutex::new(State::Indexed(files)),
        }
    }

-    pub fn get(&self) -> Index {
+    pub(super) fn get(&self) -> Index {
        let state = self.state.lock().unwrap();

        match &*state {
            State::Lazy => Index::Lazy(LazyFiles { files: state }),
-            State::Indexed(files) => Index::Indexed(files.clone()),
+            State::Indexed(files) => Index::Indexed(Indexed {
+                files: Arc::clone(files),
+                _lifetime: PhantomData,
+            }),
        }
    }

-    pub fn is_lazy(&self) -> bool {
+    pub(super) fn is_lazy(&self) -> bool {
        matches!(*self.state.lock().unwrap(), State::Lazy)
    }

    /// Returns a mutable view on the index that allows cheap in-place mutations.
    ///
    /// The changes are automatically written back to the database once the view is dropped.
-    pub fn indexed_mut(db: &mut dyn Db, package: Package) -> Option<IndexedFilesMut> {
+    pub(super) fn indexed_mut(db: &mut dyn Db, package: Package) -> Option<IndexedMut> {
        // Calling `zalsa_mut` cancels all pending salsa queries. This ensures that there are no pending
        // reads to the file set.
        // TODO: Use a non-internal API instead https://salsa.zulipchat.com/#narrow/stream/333573-salsa-3.2E0/topic/Expose.20an.20API.20to.20cancel.20other.20queries
        let _ = db.as_dyn_database_mut().zalsa_mut();

-        let files = package.file_set(db);
-
-        let indexed = match &*files.state.lock().unwrap() {
-            State::Lazy => return None,
-            State::Indexed(indexed) => indexed.clone(),
+        // Replace the state with lazy. The `IndexedMut` guard restores the state
+        // to `State::Indexed`  or sets a new `PackageFiles` when it gets dropped to ensure the state
+        // is restored to how it has been before replacing the value.
+        //
+        // It isn't necessary to hold on to the lock after this point:
+        // * The above call to `zalsa_mut` guarantees that there's exactly **one** DB reference.
+        // * `Indexed` has a `'db` lifetime, and this method requires a `&mut db`.
+        //   This means that there can't be any pending reference to `Indexed` because Rust
+        //   doesn't allow borrowing `db` as mutable (to call this method) and immutable (`Indexed<'db>`) at the same time.
+        //   There can't be any other `Indexed<'db>` references created by clones of this DB because
+        //   all clones must have been dropped at this point and the `Indexed`
+        //   can't outlive the database (constrained by the `db` lifetime).
+        let state = {
+            let files = package.file_set(db);
+            let mut locked = files.state.lock().unwrap();
+            std::mem::replace(&mut *locked, State::Lazy)
        };

-        Some(IndexedFilesMut {
+        let indexed = match state {
+            // If it's already lazy, just return. We also don't need to restore anything because the
+            // replace above was a no-op.
+            State::Lazy => return None,
+            State::Indexed(indexed) => indexed,
+        };
+
+        Some(IndexedMut {
            db: Some(db),
            package,
-            new_revision: indexed.revision,
-            indexed,
+            files: indexed,
+            did_change: false,
        })
    }
 }
@@ -88,152 +112,93 @@ enum State {
    Lazy,

    /// The files are indexed. Stores the known files of a package.
-    Indexed(IndexedFiles),
+    Indexed(FileSet),
 }

-pub enum Index<'a> {
+pub(super) enum Index<'db> {
    /// The index has not yet been computed. Allows inserting the files.
-    Lazy(LazyFiles<'a>),
+    Lazy(LazyFiles<'db>),

-    Indexed(IndexedFiles),
+    Indexed(Indexed<'db>),
 }

 /// Package files that have not been indexed yet.
-pub struct LazyFiles<'a> {
-    files: std::sync::MutexGuard<'a, State>,
+pub(super) struct LazyFiles<'db> {
+    files: std::sync::MutexGuard<'db, State>,
 }

-impl<'a> LazyFiles<'a> {
+impl<'db> LazyFiles<'db> {
    /// Sets the indexed files of a package to `files`.
-    pub fn set(mut self, files: FxHashSet<File>) -> IndexedFiles {
-        let files = IndexedFiles::new(files);
-        *self.files = State::Indexed(files.clone());
+    pub(super) fn set(mut self, files: FxHashSet<File>) -> Indexed<'db> {
+        let files = Indexed {
+            files: Arc::new(files),
+            _lifetime: PhantomData,
+        };
+        *self.files = State::Indexed(Arc::clone(&files.files));
        files
    }
 }

 /// The indexed files of a package.
 ///
-/// # Salsa integration
-/// The type is cheap clonable and allows for in-place mutation of the files. The in-place mutation requires
-/// extra care because the type is used as the result of Salsa queries and Salsa relies on a type's equality
-/// to determine if the output has changed. This is accomplished by using a `revision` that gets incremented
-/// whenever the files are changed. The revision ensures that salsa's comparison of the
-/// previous [`IndexedFiles`] with the next [`IndexedFiles`] returns false even though they both
-/// point to the same underlying hash set.
-///
-/// # Equality
-/// Two [`IndexedFiles`] are only equal if they have the same revision and point to the **same** (identity) hash set.
-#[derive(Debug, Clone)]
-pub struct IndexedFiles {
-    revision: u64,
-    files: Arc<std::sync::Mutex<FxHashSet<File>>>,
+/// Note: This type is intentionally non-cloneable. Making it cloneable requires
+/// revisiting the locking behavior in [`PackageFiles::indexed_mut`].
+#[derive(Debug, PartialEq, Eq)]
+pub struct Indexed<'db> {
+    files: FileSet,
+    // Preserve the lifetime of `PackageFiles`.
+    _lifetime: PhantomData<&'db ()>,
 }

-impl IndexedFiles {
-    fn new(files: FxHashSet<File>) -> Self {
-        Self {
-            files: Arc::new(std::sync::Mutex::new(files)),
-            revision: 0,
-        }
-    }
-
-    /// Locks the file index for reading.
-    pub fn read(&self) -> IndexedFilesGuard {
-        IndexedFilesGuard {
-            guard: self.files.lock().unwrap(),
-        }
-    }
-}
-
-impl PartialEq for IndexedFiles {
-    fn eq(&self, other: &Self) -> bool {
-        self.revision == other.revision && Arc::ptr_eq(&self.files, &other.files)
-    }
-}
-
-impl Eq for IndexedFiles {}
-
-pub struct IndexedFilesGuard<'a> {
-    guard: std::sync::MutexGuard<'a, FxHashSet<File>>,
-}
-
-impl Deref for IndexedFilesGuard<'_> {
+impl Deref for Indexed<'_> {
    type Target = FxHashSet<File>;

    fn deref(&self) -> &Self::Target {
-        &self.guard
+        &self.files
    }
 }

-impl<'a> IntoIterator for &'a IndexedFilesGuard<'a> {
+impl<'a> IntoIterator for &'a Indexed<'_> {
    type Item = File;
-    type IntoIter = IndexedFilesIter<'a>;
+    type IntoIter = std::iter::Copied<std::collections::hash_set::Iter<'a, File>>;

    fn into_iter(self) -> Self::IntoIter {
-        IndexedFilesIter {
-            inner: self.guard.iter(),
-        }
+        self.files.iter().copied()
    }
 }

-/// Iterator over the indexed files.
-///
-/// # Locks
-/// Holding on to the iterator locks the file index for reading.
-pub struct IndexedFilesIter<'a> {
-    inner: std::collections::hash_set::Iter<'a, File>,
-}
-
-impl<'a> Iterator for IndexedFilesIter<'a> {
-    type Item = File;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.inner.next().copied()
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.inner.size_hint()
-    }
-}
-
-impl FusedIterator for IndexedFilesIter<'_> {}
-
-impl ExactSizeIterator for IndexedFilesIter<'_> {}
-
 /// A Mutable view of a package's indexed files.
 ///
 /// Allows in-place mutation of the files without deep cloning the hash set.
 /// The changes are written back when the mutable view is dropped or by calling [`Self::set`] manually.
-pub struct IndexedFilesMut<'db> {
+pub(super) struct IndexedMut<'db> {
    db: Option<&'db mut dyn Db>,
    package: Package,
-    indexed: IndexedFiles,
-    new_revision: u64,
+    files: FileSet,
+    did_change: bool,
 }

-impl IndexedFilesMut<'_> {
-    pub fn insert(&mut self, file: File) -> bool {
-        if self.indexed.files.lock().unwrap().insert(file) {
-            self.new_revision += 1;
+impl IndexedMut<'_> {
+    pub(super) fn insert(&mut self, file: File) -> bool {
+        if self.files_mut().insert(file) {
+            self.did_change = true;
            true
        } else {
            false
        }
    }

-    pub fn remove(&mut self, file: File) -> bool {
-        if self.indexed.files.lock().unwrap().remove(&file) {
-            self.new_revision += 1;
+    pub(super) fn remove(&mut self, file: File) -> bool {
+        if self.files_mut().remove(&file) {
+            self.did_change = true;
            true
        } else {
            false
        }
    }

-    /// Writes the changes back to the database.
-    pub fn set(mut self) {
-        self.set_impl();
+    fn files_mut(&mut self) -> &mut FxHashSet<File> {
+        Arc::get_mut(&mut self.files).expect("All references to `FilesSet` to have been dropped")
    }

    fn set_impl(&mut self) {
@@ -241,19 +206,70 @@ impl IndexedFilesMut<'_> {
            return;
        };

-        if self.indexed.revision != self.new_revision {
+        let files = Arc::clone(&self.files);
+
+        if self.did_change {
+            // If there are changes, set the new file_set to trigger a salsa revision change.
            self.package
                .set_file_set(db)
-                .to(PackageFiles::indexed(IndexedFiles {
-                    revision: self.new_revision,
-                    files: self.indexed.files.clone(),
-                }));
+                .to(PackageFiles::indexed(files));
+        } else {
+            // The `indexed_mut` replaced the `state` with Lazy. Restore it back to the indexed state.
+            *self.package.file_set(db).state.lock().unwrap() = State::Indexed(files);
        }
    }
 }

-impl Drop for IndexedFilesMut<'_> {
+impl Drop for IndexedMut<'_> {
    fn drop(&mut self) {
        self.set_impl();
    }
 }
+
+#[cfg(test)]
+mod tests {
+    use rustc_hash::FxHashSet;
+
+    use ruff_db::files::system_path_to_file;
+    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
+    use ruff_python_ast::name::Name;
+
+    use crate::db::tests::TestDb;
+    use crate::workspace::files::Index;
+    use crate::workspace::Package;
+
+    #[test]
+    fn re_entrance() -> anyhow::Result<()> {
+        let mut db = TestDb::new();
+
+        db.write_file("test.py", "")?;
+
+        let package = Package::new(&db, Name::new("test"), SystemPathBuf::from("/test"));
+
+        let file = system_path_to_file(&db, "test.py").unwrap();
+
+        let files = match package.file_set(&db).get() {
+            Index::Lazy(lazy) => lazy.set(FxHashSet::from_iter([file])),
+            Index::Indexed(files) => files,
+        };
+
+        // Calling files a second time should not dead-lock.
+        // This can e.g. happen when `check_file` iterates over all files and
+        // `is_file_open` queries the open files.
+        let files_2 = package.file_set(&db).get();
+
+        match files_2 {
+            Index::Lazy(_) => {
+                panic!("Expected indexed files, got lazy files");
+            }
+            Index::Indexed(files_2) => {
+                assert_eq!(
+                    files_2.iter().collect::<Vec<_>>(),
+                    files.iter().collect::<Vec<_>>()
+                );
+            }
+        }
+
+        Ok(())
+    }
+}
--- a/crates/red_knot_workspace/src/workspace/metadata.rs
+++ b/crates/red_knot_workspace/src/workspace/metadata.rs
@@ -1,3 +1,4 @@
+use crate::workspace::settings::{Configuration, WorkspaceSettings};
 use ruff_db::system::{System, SystemPath, SystemPathBuf};
 use ruff_python_ast::name::Name;

@@ -7,6 +8,8 @@ pub struct WorkspaceMetadata {

    /// The (first-party) packages in this workspace.
    pub(super) packages: Vec<PackageMetadata>,
+
+    pub(super) settings: WorkspaceSettings,
 }

 /// A first-party package in a workspace.
@@ -21,7 +24,11 @@ pub struct PackageMetadata {

 impl WorkspaceMetadata {
    /// Discovers the closest workspace at `path` and returns its metadata.
-    pub fn from_path(path: &SystemPath, system: &dyn System) -> anyhow::Result<WorkspaceMetadata> {
+    pub fn from_path(
+        path: &SystemPath,
+        system: &dyn System,
+        base_configuration: Option<Configuration>,
+    ) -> anyhow::Result<WorkspaceMetadata> {
        assert!(
            system.is_directory(path),
            "Workspace root path must be a directory"
@@ -38,9 +45,20 @@ impl WorkspaceMetadata {
            root: root.clone(),
        };

+        // TODO: Load the configuration from disk.
+        let mut configuration = Configuration::default();
+
+        if let Some(base_configuration) = base_configuration {
+            configuration.extend(base_configuration);
+        }
+
+        // TODO: Respect the package configurations when resolving settings (e.g. for the target version).
+        let settings = configuration.into_workspace_settings(&root);
+
        let workspace = WorkspaceMetadata {
            root,
            packages: vec![package],
+            settings,
        };

        Ok(workspace)
@@ -53,6 +71,10 @@ impl WorkspaceMetadata {
    pub fn packages(&self) -> &[PackageMetadata] {
        &self.packages
    }
+
+    pub fn settings(&self) -> &WorkspaceSettings {
+        &self.settings
+    }
 }

 impl PackageMetadata {
--- a/crates/red_knot_workspace/src/workspace/settings.rs
+++ b/crates/red_knot_workspace/src/workspace/settings.rs
@@ -0,0 +1,89 @@
+use red_knot_python_semantic::{ProgramSettings, PythonVersion, SearchPathSettings, SitePackages};
+use ruff_db::system::{SystemPath, SystemPathBuf};
+
+/// The resolved configurations.
+///
+/// The main difference to [`Configuration`] is that default values are filled in.
+#[derive(Debug, Clone)]
+pub struct WorkspaceSettings {
+    pub(super) program: ProgramSettings,
+}
+
+impl WorkspaceSettings {
+    pub fn program(&self) -> &ProgramSettings {
+        &self.program
+    }
+}
+
+/// The configuration for the workspace or a package.
+#[derive(Debug, Default, Clone)]
+pub struct Configuration {
+    pub target_version: Option<PythonVersion>,
+    pub search_paths: SearchPathConfiguration,
+}
+
+impl Configuration {
+    /// Extends this configuration by using the values from `with` for all values that are absent in `self`.
+    pub fn extend(&mut self, with: Configuration) {
+        self.target_version = self.target_version.or(with.target_version);
+        self.search_paths.extend(with.search_paths);
+    }
+
+    pub fn into_workspace_settings(self, workspace_root: &SystemPath) -> WorkspaceSettings {
+        WorkspaceSettings {
+            program: ProgramSettings {
+                target_version: self.target_version.unwrap_or_default(),
+                search_paths: self.search_paths.into_settings(workspace_root),
+            },
+        }
+    }
+}
+
+#[derive(Debug, Default, Clone, Eq, PartialEq)]
+pub struct SearchPathConfiguration {
+    /// List of user-provided paths that should take first priority in the module resolution.
+    /// Examples in other type checkers are mypy's MYPYPATH environment variable,
+    /// or pyright's stubPath configuration setting.
+    pub extra_paths: Option<Vec<SystemPathBuf>>,
+
+    /// The root of the workspace, used for finding first-party modules.
+    pub src_root: Option<SystemPathBuf>,
+
+    /// Optional path to a "custom typeshed" directory on disk for us to use for standard-library types.
+    /// If this is not provided, we will fallback to our vendored typeshed stubs for the stdlib,
+    /// bundled as a zip file in the binary
+    pub custom_typeshed: Option<SystemPathBuf>,
+
+    /// The path to the user's `site-packages` directory, where third-party packages from ``PyPI`` are installed.
+    pub site_packages: Option<SitePackages>,
+}
+
+impl SearchPathConfiguration {
+    pub fn into_settings(self, workspace_root: &SystemPath) -> SearchPathSettings {
+        let site_packages = self.site_packages.unwrap_or(SitePackages::Known(vec![]));
+
+        SearchPathSettings {
+            extra_paths: self.extra_paths.unwrap_or_default(),
+            src_root: self
+                .src_root
+                .unwrap_or_else(|| workspace_root.to_path_buf()),
+            custom_typeshed: self.custom_typeshed,
+            site_packages,
+        }
+    }
+
+    pub fn extend(&mut self, with: SearchPathConfiguration) {
+        if let Some(extra_paths) = with.extra_paths {
+            self.extra_paths.get_or_insert(extra_paths);
+        }
+        if let Some(src_root) = with.src_root {
+            self.src_root.get_or_insert(src_root);
+        }
+        if let Some(custom_typeshed) = with.custom_typeshed {
+            self.custom_typeshed.get_or_insert(custom_typeshed);
+        }
+        if let Some(site_packages) = with.site_packages {
+            self.site_packages.get_or_insert(site_packages);
+        }
+    }
+}
--- a/crates/red_knot_workspace/tests/check.rs
+++ b/crates/red_knot_workspace/tests/check.rs
@@ -1,6 +1,7 @@
-use red_knot_python_semantic::{
-    HasTy, ProgramSettings, PythonVersion, SearchPathSettings, SemanticModel,
-};
+use std::fs;
+use std::path::PathBuf;
+
+use red_knot_python_semantic::{HasTy, SemanticModel};
 use red_knot_workspace::db::RootDatabase;
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File};
@@ -9,23 +10,11 @@ use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
 use ruff_python_ast::visitor::source_order;
 use ruff_python_ast::visitor::source_order::SourceOrderVisitor;
 use ruff_python_ast::{Alias, Expr, Parameter, ParameterWithDefault, Stmt};
-use std::fs;
-use std::path::PathBuf;

-fn setup_db(workspace_root: SystemPathBuf) -> anyhow::Result<RootDatabase> {
-    let system = OsSystem::new(&workspace_root);
-    let workspace = WorkspaceMetadata::from_path(&workspace_root, &system)?;
-    let search_paths = SearchPathSettings {
-        extra_paths: vec![],
-        src_root: workspace_root,
-        custom_typeshed: None,
-        site_packages: vec![],
-    };
-    let settings = ProgramSettings {
-        target_version: PythonVersion::default(),
-        search_paths,
-    };
-    RootDatabase::new(workspace, settings, system)
+fn setup_db(workspace_root: &SystemPath) -> anyhow::Result<RootDatabase> {
+    let system = OsSystem::new(workspace_root);
+    let workspace = WorkspaceMetadata::from_path(workspace_root, &system, None)?;
+    RootDatabase::new(workspace, system)
 }

 /// Test that all snippets in testcorpus can be checked without panic
@@ -33,8 +22,9 @@ fn setup_db(workspace_root: SystemPathBuf) -> anyhow::Result<RootDatabase> {
 #[allow(clippy::print_stdout)]
 fn corpus_no_panic() -> anyhow::Result<()> {
    let corpus = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("resources/test/corpus");
-    let system_corpus = SystemPath::from_std_path(&corpus).expect("corpus path to be UTF8");
-    let db = setup_db(system_corpus.to_path_buf())?;
+    let system_corpus =
+        SystemPathBuf::from_path_buf(corpus.clone()).expect("corpus path to be UTF8");
+    let db = setup_db(&system_corpus)?;

    for path in fs::read_dir(&corpus).expect("corpus to be a directory") {
        let path = path.expect("path to not be an error").path();
--- a/crates/ruff/Cargo.toml
+++ b/crates/ruff/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.6.1"
+version = "0.6.2"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }
--- a/crates/ruff/src/commands/snapshots/ruffcommandschecktestE902_E902.py.snap
+++ b/crates/ruff/src/commands/snapshots/ruffcommandschecktestE902_E902.py.snap
@@ -1,7 +1,8 @@
 ---
 source: crates/ruff/src/commands/check.rs
 ---
-/home/ferris/project/code.py:1:1: E902 Permission denied (os error 13)
-/home/ferris/project/notebook.ipynb:1:1: E902 Permission denied (os error 13)
-/home/ferris/project/pyproject.toml:1:1: E902 Permission denied (os error 13)
+error[E902]: /home/ferris/project/code.py:1:1: Permission denied (os error 13)

+error[E902]: /home/ferris/project/notebook.ipynb:1:1: Permission denied (os error 13)
+
+error[E902]: /home/ferris/project/pyproject.toml:1:1: Permission denied (os error 13)
--- a/crates/ruff/tests/lint.rs
+++ b/crates/ruff/tests/lint.rs
@@ -45,9 +45,12 @@ inline-quotes = "single"
        success: false
        exit_code: 1
        ----- stdout -----
-        test.py:1:5: Q000 [*] Double quotes found but single quotes preferred
-        test.py:1:5: B005 Using `.strip()` with multi-character strings is misleading
-        test.py:1:19: Q000 [*] Double quotes found but single quotes preferred
+        error[Q000]: test.py:1:5: [*] Double quotes found but single quotes preferred
+
+        error[B005]: test.py:1:5: Using `.strip()` with multi-character strings is misleading
+
+        error[Q000]: test.py:1:19: [*] Double quotes found but single quotes preferred
+
        Found 3 errors.
        [*] 2 fixable with the `--fix` option.

@@ -88,9 +91,12 @@ inline-quotes = "single"
    success: false
    exit_code: 1
    ----- stdout -----
-    -:1:5: Q000 [*] Double quotes found but single quotes preferred
-    -:1:5: B005 Using `.strip()` with multi-character strings is misleading
-    -:1:19: Q000 [*] Double quotes found but single quotes preferred
+    error[Q000]: -:1:5: [*] Double quotes found but single quotes preferred
+
+    error[B005]: -:1:5: Using `.strip()` with multi-character strings is misleading
+
+    error[Q000]: -:1:19: [*] Double quotes found but single quotes preferred
+
    Found 3 errors.
    [*] 2 fixable with the `--fix` option.

@@ -128,9 +134,12 @@ inline-quotes = "single"
    success: false
    exit_code: 1
    ----- stdout -----
-    -:1:5: Q000 [*] Double quotes found but single quotes preferred
-    -:1:5: B005 Using `.strip()` with multi-character strings is misleading
-    -:1:19: Q000 [*] Double quotes found but single quotes preferred
+    error[Q000]: -:1:5: [*] Double quotes found but single quotes preferred
+
+    error[B005]: -:1:5: Using `.strip()` with multi-character strings is misleading
+
+    error[Q000]: -:1:19: [*] Double quotes found but single quotes preferred
+
    Found 3 errors.
    [*] 2 fixable with the `--fix` option.

@@ -174,9 +183,12 @@ inline-quotes = "single"
    success: false
    exit_code: 1
    ----- stdout -----
-    -:1:5: Q000 [*] Double quotes found but single quotes preferred
-    -:1:5: B005 Using `.strip()` with multi-character strings is misleading
-    -:1:19: Q000 [*] Double quotes found but single quotes preferred
+    error[Q000]: -:1:5: [*] Double quotes found but single quotes preferred
+
+    error[B005]: -:1:5: Using `.strip()` with multi-character strings is misleading
+
+    error[Q000]: -:1:19: [*] Double quotes found but single quotes preferred
+
    Found 3 errors.
    [*] 2 fixable with the `--fix` option.

@@ -255,9 +267,12 @@ OTHER = "OTHER"
    success: false
    exit_code: 1
    ----- stdout -----
-    main.py:4:16: Q000 [*] Double quotes found but single quotes preferred
-    main.py:5:12: Q000 [*] Double quotes found but single quotes preferred
-    test.py:3:15: Q000 [*] Double quotes found but single quotes preferred
+    error[Q000]: main.py:4:16: [*] Double quotes found but single quotes preferred
+
+    error[Q000]: main.py:5:12: [*] Double quotes found but single quotes preferred
+
+    error[Q000]: test.py:3:15: [*] Double quotes found but single quotes preferred
+
    Found 3 errors.
    [*] 3 fixable with the `--fix` option.

@@ -305,8 +320,10 @@ if __name__ == "__main__":
    success: false
    exit_code: 1
    ----- stdout -----
-    generated.py:4:16: Q000 [*] Double quotes found but single quotes preferred
-    generated.py:5:12: Q000 [*] Double quotes found but single quotes preferred
+    error[Q000]: generated.py:4:16: [*] Double quotes found but single quotes preferred
+
+    error[Q000]: generated.py:5:12: [*] Double quotes found but single quotes preferred
+
    Found 2 errors.
    [*] 2 fixable with the `--fix` option.

@@ -352,7 +369,8 @@ _ = "---------------------------------------------------------------------------
    success: false
    exit_code: 1
    ----- stdout -----
-    test.py:5:91: E501 Line too long (109 > 100)
+    error[E501]: test.py:5:91: Line too long (109 > 100)
+
    Found 1 error.

    ----- stderr -----
@@ -400,7 +418,8 @@ if __name__ == "__main__":
    success: false
    exit_code: 1
    ----- stdout -----
-    generated.py:2:8: F401 [*] `os` imported but unused
+    error[F401]: generated.py:2:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -448,7 +467,8 @@ if __name__ == "__main__":
    success: false
    exit_code: 1
    ----- stdout -----
-    generated.py:2:8: F401 [*] `os` imported but unused
+    error[F401]: generated.py:2:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -684,8 +704,10 @@ x = "longer_than_90_charactersssssssssssssssssssssssssssssssssssssssssssssssssss
    success: false
    exit_code: 1
    ----- stdout -----
-    -:2:1: I001 [*] Import block is un-sorted or un-formatted
-    -:15:91: E501 Line too long (97 > 90)
+    error[I001]: -:2:1: [*] Import block is un-sorted or un-formatted
+
+    error[E501]: -:15:91: Line too long (97 > 90)
+
    Found 2 errors.
    [*] 1 fixable with the `--fix` option.

@@ -809,7 +831,8 @@ select=["E501"]
    success: false
    exit_code: 1
    ----- stdout -----
-    -:1:91: E501 Line too long (97 > 90)
+    error[E501]: -:1:91: Line too long (97 > 90)
+
    Found 1 error.

    ----- stderr -----
@@ -851,7 +874,8 @@ fn deprecated_config_option_overridden_via_cli() {
    success: false
    exit_code: 1
    ----- stdout -----
-    -:1:7: N801 Class name `lowercase` should use CapWords convention
+    error[N801]: -:1:7: Class name `lowercase` should use CapWords convention
+
    Found 1 error.

    ----- stderr -----
@@ -925,7 +949,8 @@ include = ["*.ipy"]
    success: false
    exit_code: 1
    ----- stdout -----
-    main.ipy:cell 1:1:8: F401 [*] `os` imported but unused
+    error[F401]: main.ipy:cell 1:1:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -963,7 +988,8 @@ import os
    success: false
    exit_code: 1
    ----- stdout -----
-    -:3:8: F401 [*] `os` imported but unused
+    error[F401]: -:3:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -1041,7 +1067,8 @@ import os
    success: false
    exit_code: 1
    ----- stdout -----
-    -:2:8: F401 [*] `os` imported but unused
+    error[F401]: -:2:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -1118,7 +1145,8 @@ import os
    success: false
    exit_code: 1
    ----- stdout -----
-    -:2:8: F401 [*] `os` imported but unused
+    error[F401]: -:2:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -1159,7 +1187,8 @@ def func():
    success: false
    exit_code: 1
    ----- stdout -----
-    -:2:8: F401 [*] `os` imported but unused
+    error[F401]: -:2:8: [*] `os` imported but unused
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -1197,7 +1226,8 @@ fn negated_per_file_ignores() -> Result<()> {
    success: false
    exit_code: 1
    ----- stdout -----
-    selected.py:1:1: RUF901 [*] Hey this is a stable test rule with a safe fix.
+    error[RUF901]: selected.py:1:1: [*] Hey this is a stable test rule with a safe fix.
+
    Found 1 error.
    [*] 1 fixable with the `--fix` option.

@@ -1239,7 +1269,8 @@ fn negated_per_file_ignores_absolute() -> Result<()> {
        success: false
        exit_code: 1
        ----- stdout -----
-        src/selected.py:1:1: RUF901 [*] Hey this is a stable test rule with a safe fix.
+        error[RUF901]: src/selected.py:1:1: [*] Hey this is a stable test rule with a safe fix.
+
        Found 1 error.
        [*] 1 fixable with the `--fix` option.

--- a/crates/ruff_benchmark/benches/red_knot.rs
+++ b/crates/ruff_benchmark/benches/red_knot.rs
@@ -1,7 +1,9 @@
 #![allow(clippy::disallowed_names)]

-use red_knot_python_semantic::{ProgramSettings, PythonVersion, SearchPathSettings};
+use red_knot_python_semantic::PythonVersion;
 use red_knot_workspace::db::RootDatabase;
+use red_knot_workspace::watch::{ChangeEvent, ChangedKind};
+use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_benchmark::criterion::{criterion_group, criterion_main, BatchSize, Criterion};
 use ruff_benchmark::TestFile;
@@ -12,13 +14,53 @@ use ruff_db::system::{MemoryFileSystem, SystemPath, TestSystem};
 struct Case {
    db: RootDatabase,
    fs: MemoryFileSystem,
-    parser: File,
    re: File,
    re_path: &'static SystemPath,
 }

 const TOMLLIB_312_URL: &str = "https://raw.githubusercontent.com/python/cpython/8e8a4baf652f6e1cee7acde9d78c4b6154539748/Lib/tomllib";

+// This first "unresolved import" is because we don't understand `*` imports yet.
+// The following "unresolved import" violations are because we can't distinguish currently from
+// "Symbol exists in the module but its type is unknown" and
+// "Symbol does not exist in the module"
+static EXPECTED_DIAGNOSTICS: &[&str] = &[
+    "/src/tomllib/_parser.py:7:29: Could not resolve import of 'Iterable' from 'collections.abc'",
+    "/src/tomllib/_parser.py:10:20: Could not resolve import of 'Any' from 'typing'",
+    "/src/tomllib/_parser.py:13:5: Could not resolve import of 'RE_DATETIME' from '._re'",
+    "/src/tomllib/_parser.py:14:5: Could not resolve import of 'RE_LOCALTIME' from '._re'",
+    "/src/tomllib/_parser.py:15:5: Could not resolve import of 'RE_NUMBER' from '._re'",
+    "/src/tomllib/_parser.py:20:21: Could not resolve import of 'Key' from '._types'",
+    "/src/tomllib/_parser.py:20:26: Could not resolve import of 'ParseFloat' from '._types'",
+    "Line 69 is too long (89 characters)",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "Use double quotes for strings",
+    "/src/tomllib/_parser.py:153:22: Name 'key' used when not defined.",
+    "/src/tomllib/_parser.py:153:27: Name 'flag' used when not defined.",
+    "/src/tomllib/_parser.py:159:16: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:161:25: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:168:16: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:169:22: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:170:25: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:180:16: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:182:31: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:206:16: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:207:22: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:208:25: Name 'k' used when not defined.",
+    "/src/tomllib/_parser.py:330:32: Name 'header' used when not defined.",
+    "/src/tomllib/_parser.py:330:41: Name 'key' used when not defined.",
+    "/src/tomllib/_parser.py:333:26: Name 'cont_key' used when not defined.",
+    "/src/tomllib/_parser.py:334:71: Name 'cont_key' used when not defined.",
+    "/src/tomllib/_parser.py:337:31: Name 'cont_key' used when not defined.",
+    "/src/tomllib/_parser.py:628:75: Name 'e' used when not defined.",
+    "/src/tomllib/_parser.py:686:23: Name 'parse_float' used when not defined.",
+];
+
 fn get_test_file(name: &str) -> TestFile {
    let path = format!("tomllib/{name}");
    let url = format!("{TOMLLIB_312_URL}/{name}");
@@ -28,31 +70,34 @@ fn get_test_file(name: &str) -> TestFile {
 fn setup_case() -> Case {
    let system = TestSystem::default();
    let fs = system.memory_file_system().clone();
-    let init_path = SystemPath::new("/src/tomllib/__init__.py");
    let parser_path = SystemPath::new("/src/tomllib/_parser.py");
    let re_path = SystemPath::new("/src/tomllib/_re.py");
-    let types_path = SystemPath::new("/src/tomllib/_types.py");
    fs.write_files([
-        (init_path, get_test_file("__init__.py").code()),
+        (
+            SystemPath::new("/src/tomllib/__init__.py"),
+            get_test_file("__init__.py").code(),
+        ),
        (parser_path, get_test_file("_parser.py").code()),
        (re_path, get_test_file("_re.py").code()),
-        (types_path, get_test_file("_types.py").code()),
+        (
+            SystemPath::new("/src/tomllib/_types.py"),
+            get_test_file("_types.py").code(),
+        ),
    ])
    .unwrap();

    let src_root = SystemPath::new("/src");
-    let metadata = WorkspaceMetadata::from_path(src_root, &system).unwrap();
-    let settings = ProgramSettings {
-        target_version: PythonVersion::PY312,
-        search_paths: SearchPathSettings {
-            extra_paths: vec![],
-            src_root: src_root.to_path_buf(),
-            site_packages: vec![],
-            custom_typeshed: None,
-        },
-    };
+    let metadata = WorkspaceMetadata::from_path(
+        src_root,
+        &system,
+        Some(Configuration {
+            target_version: Some(PythonVersion::PY312),
+            ..Configuration::default()
+        }),
+    )
+    .unwrap();

-    let mut db = RootDatabase::new(metadata, settings, system).unwrap();
+    let mut db = RootDatabase::new(metadata, system).unwrap();
    let parser = system_path_to_file(&db, parser_path).unwrap();

    db.workspace().open_file(&mut db, parser);
@@ -62,7 +107,6 @@ fn setup_case() -> Case {
    Case {
        db,
        fs,
-        parser,
        re,
        re_path,
    }
@@ -72,8 +116,8 @@ fn benchmark_incremental(criterion: &mut Criterion) {
    criterion.bench_function("red_knot_check_file[incremental]", |b| {
        b.iter_batched_ref(
            || {
-                let mut case = setup_case();
-                case.db.check_file(case.parser).unwrap();
+                let case = setup_case();
+                case.db.check().unwrap();

                case.fs
                    .write_file(
@@ -82,14 +126,22 @@ fn benchmark_incremental(criterion: &mut Criterion) {
                    )
                    .unwrap();

-                case.re.sync(&mut case.db);
                case
            },
            |case| {
-                let Case { db, parser, .. } = case;
-                let result = db.check_file(*parser).unwrap();
+                let Case { db, .. } = case;

-                assert_eq!(result.len(), 34);
+                db.apply_changes(
+                    vec![ChangeEvent::Changed {
+                        path: case.re_path.to_path_buf(),
+                        kind: ChangedKind::FileContent,
+                    }],
+                    None,
+                );
+
+                let result = db.check().unwrap();
+
+                assert_eq!(result, EXPECTED_DIAGNOSTICS);
            },
            BatchSize::SmallInput,
        );
@@ -101,10 +153,10 @@ fn benchmark_cold(criterion: &mut Criterion) {
        b.iter_batched_ref(
            setup_case,
            |case| {
-                let Case { db, parser, .. } = case;
-                let result = db.check_file(*parser).unwrap();
+                let Case { db, .. } = case;
+                let result = db.check().unwrap();

-                assert_eq!(result.len(), 34);
+                assert_eq!(result, EXPECTED_DIAGNOSTICS);
            },
            BatchSize::SmallInput,
        );
--- a/crates/ruff_db/src/files.rs
+++ b/crates/ruff_db/src/files.rs
@@ -85,7 +85,7 @@ impl Files {
            .system_by_path
            .entry(absolute.clone())
            .or_insert_with(|| {
-                tracing::trace!("Adding file {path}");
+                tracing::trace!("Adding file '{path}'");

                let metadata = db.system().path_metadata(path);
                let durability = self
@@ -131,7 +131,7 @@ impl Files {
                    Err(_) => return Err(FileError::NotFound),
                };

-                tracing::trace!("Adding vendored file {}", path);
+                tracing::trace!("Adding vendored file '{}'", path);
                let file = File::builder(FilePath::Vendored(path.to_path_buf()))
                    .permissions(Some(0o444))
                    .revision(metadata.revision())
@@ -158,7 +158,7 @@ impl Files {
            Entry::Vacant(entry) => {
                let metadata = db.system().virtual_path_metadata(path).ok()?;

-                tracing::trace!("Adding virtual file {}", path);
+                tracing::trace!("Adding virtual file '{}'", path);

                let file = File::builder(FilePath::SystemVirtual(path.to_path_buf()))
                    .revision(metadata.revision())
@@ -211,7 +211,7 @@ impl Files {
    /// That's why [`File::sync_path`] and [`File::sync_path`] is preferred if it is known that the path is a file.
    pub fn sync_recursively(db: &mut dyn Db, path: &SystemPath) {
        let path = SystemPath::absolute(path, db.system().current_directory());
-        tracing::debug!("Syncing all files in {path}");
+        tracing::debug!("Syncing all files in '{path}'");

        let inner = Arc::clone(&db.files().inner);
        for entry in inner.system_by_path.iter_mut() {
@@ -224,9 +224,7 @@ impl Files {

        for root in roots.all() {
            if root.path(db).starts_with(&path) {
-                root.set_revision(db)
-                    .with_durability(Durability::HIGH)
-                    .to(FileRevision::now());
+                root.set_revision(db).to(FileRevision::now());
            }
        }
    }
@@ -249,9 +247,7 @@ impl Files {
        let roots = inner.roots.read().unwrap();

        for root in roots.all() {
-            root.set_revision(db)
-                .with_durability(Durability::HIGH)
-                .to(FileRevision::now());
+            root.set_revision(db).to(FileRevision::now());
        }
    }

@@ -381,23 +377,17 @@ impl File {
            return;
        };
        let metadata = db.system().path_metadata(path);
-        let durability = db.files().root(db, path).map(|root| root.durability(db));
-        Self::sync_impl(db, metadata, file, durability);
+        Self::sync_impl(db, metadata, file);
    }

    fn sync_system_virtual_path(db: &mut dyn Db, path: &SystemVirtualPath, file: File) {
        let metadata = db.system().virtual_path_metadata(path);
-        Self::sync_impl(db, metadata, file, None);
+        Self::sync_impl(db, metadata, file);
    }

    /// Private method providing the implementation for [`Self::sync_system_path`] and
    /// [`Self::sync_system_virtual_path`].
-    fn sync_impl(
-        db: &mut dyn Db,
-        metadata: crate::system::Result<Metadata>,
-        file: File,
-        durability: Option<Durability>,
-    ) {
+    fn sync_impl(db: &mut dyn Db, metadata: crate::system::Result<Metadata>, file: File) {
        let (status, revision, permission) = match metadata {
            Ok(metadata) if metadata.file_type().is_file() => (
                FileStatus::Exists,
@@ -410,25 +400,19 @@ impl File {
            _ => (FileStatus::NotFound, FileRevision::zero(), None),
        };

-        let durability = durability.unwrap_or_default();
-
        if file.status(db) != status {
-            tracing::debug!("Updating the status of {}", file.path(db),);
-            file.set_status(db).with_durability(durability).to(status);
+            tracing::debug!("Updating the status of '{}'", file.path(db),);
+            file.set_status(db).to(status);
        }

        if file.revision(db) != revision {
-            tracing::debug!("Updating the revision of {}", file.path(db));
-            file.set_revision(db)
-                .with_durability(durability)
-                .to(revision);
+            tracing::debug!("Updating the revision of '{}'", file.path(db));
+            file.set_revision(db).to(revision);
        }

        if file.permissions(db) != permission {
-            tracing::debug!("Updating the permissions of {}", file.path(db),);
-            file.set_permissions(db)
-                .with_durability(durability)
-                .to(permission);
+            tracing::debug!("Updating the permissions of '{}'", file.path(db),);
+            file.set_permissions(db).to(permission);
        }
    }

--- a/crates/ruff_db/src/source.rs
+++ b/crates/ruff_db/src/source.rs
@@ -22,7 +22,7 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
    let kind = if is_notebook(file.path(db)) {
        file.read_to_notebook(db)
            .unwrap_or_else(|error| {
-                tracing::debug!("Failed to read notebook {path}: {error}");
+                tracing::debug!("Failed to read notebook '{path}': {error}");

                has_read_error = true;
                SourceDiagnostic(Arc::new(SourceTextError::FailedToReadNotebook(error)))
@@ -33,7 +33,7 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
    } else {
        file.read_to_string(db)
            .unwrap_or_else(|error| {
-                tracing::debug!("Failed to read file {path}: {error}");
+                tracing::debug!("Failed to read file '{path}': {error}");

                has_read_error = true;
                SourceDiagnostic(Arc::new(SourceTextError::FailedToReadFile(error))).accumulate(db);
--- a/crates/ruff_db/src/testing.rs
+++ b/crates/ruff_db/src/testing.rs
@@ -31,10 +31,20 @@ pub fn assert_const_function_query_was_not_run<Db, Q, QDb, R>(
    Db: salsa::Database,
    Q: Fn(QDb) -> R,
 {
-    let (query_name, will_execute_event) = find_will_execute_event(db, query, (), events);
+    // Salsa now interns singleton ingredients. But we know that it is a singleton, so we can just search for
+    // any event of that ingredient.
+    let query_name = query_name(&query);
+
+    let event = events.iter().find(|event| {
+        if let salsa::EventKind::WillExecute { database_key } = event.kind {
+            db.ingredient_debug_name(database_key.ingredient_index()) == query_name
+        } else {
+            false
+        }
+    });

    db.attach(|_| {
-        if let Some(will_execute_event) = will_execute_event {
+        if let Some(will_execute_event) = event {
            panic!(
                "Expected query {query_name}() not to have run but it did: {will_execute_event:?}"
            );
--- a/crates/ruff_db/src/vendored.rs
+++ b/crates/ruff_db/src/vendored.rs
@@ -97,7 +97,16 @@ impl VendoredFileSystem {
        fn read_to_string(fs: &VendoredFileSystem, path: &VendoredPath) -> Result<String> {
            let mut archive = fs.lock_archive();
            let mut zip_file = archive.lookup_path(&NormalizedVendoredPath::from(path))?;
-            let mut buffer = String::new();
+
+            // Pre-allocate the buffer with the size specified in the ZIP file metadata
+            // because `read_to_string` passes `None` as the size hint.
+            // But let's not trust the zip file metadata (even though it's vendored)
+            // and limit it to a reasonable size.
+            let mut buffer = String::with_capacity(
+                usize::try_from(zip_file.size())
+                    .unwrap_or(usize::MAX)
+                    .min(10_000_000),
+            );
            zip_file.read_to_string(&mut buffer)?;
            Ok(buffer)
        }
--- a/crates/ruff_linter/Cargo.toml
+++ b/crates/ruff_linter/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.6.1"
+version = "0.6.2"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }
@@ -29,7 +29,7 @@ ruff_source_file = { workspace = true, features = ["serde"] }
 ruff_text_size = { workspace = true }

 aho-corasick = { workspace = true }
-annotate-snippets = { workspace = true, features = ["color"] }
+annotate-snippets = { workspace = true }
 anyhow = { workspace = true }
 bitflags = { workspace = true }
 chrono = { workspace = true }
--- a/crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI053.pyi
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI053.pyi
@@ -66,3 +66,6 @@ def not_warnings_dot_deprecated(
 def not_a_deprecated_function() -> None: ...

 fbaz: str = f"51 character {foo} stringgggggggggggggggggggggggggg"  # Error: PYI053
+
+# see https://github.com/astral-sh/ruff/issues/12995
+def foo(bar: typing.Literal["a", "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"]):...
--- a/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM115.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM115.py
@@ -47,7 +47,6 @@ with contextlib.ExitStack() as exit_stack:
 open("filename", "w").close()
 pathlib.Path("filename").open("w").close()

-
 # OK (custom context manager)
 class MyFile:
    def __init__(self, filename: str):
@@ -58,3 +57,189 @@ class MyFile:

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.file.close()
+
+
+import tempfile
+import tarfile
+from tarfile import TarFile
+import zipfile
+import io
+import codecs
+import bz2
+import gzip
+import dbm
+import dbm.gnu
+import dbm.ndbm
+import dbm.dumb
+import lzma
+import shelve
+import tokenize
+import wave
+import fileinput
+
+f = tempfile.NamedTemporaryFile()
+f = tempfile.TemporaryFile()
+f = tempfile.SpooledTemporaryFile()
+f = tarfile.open("foo.tar")
+f = TarFile("foo.tar").open()
+f = tarfile.TarFile("foo.tar").open()
+f = tarfile.TarFile().open()
+f = zipfile.ZipFile("foo.zip").open("foo.txt")
+f = io.open("foo.txt")
+f = io.open_code("foo.txt")
+f = codecs.open("foo.txt")
+f = bz2.open("foo.txt")
+f = gzip.open("foo.txt")
+f = dbm.open("foo.db")
+f = dbm.gnu.open("foo.db")
+f = dbm.ndbm.open("foo.db")
+f = dbm.dumb.open("foo.db")
+f = lzma.open("foo.xz")
+f = lzma.LZMAFile("foo.xz")
+f = shelve.open("foo.db")
+f = tokenize.open("foo.py")
+f = wave.open("foo.wav")
+f = tarfile.TarFile.taropen("foo.tar")
+f = fileinput.input("foo.txt")
+f = fileinput.FileInput("foo.txt")
+
+with contextlib.suppress(Exception):
+    # The following line is for example's sake.
+    # For some f's above, this would raise an error (since it'd be f.readline() etc.)
+    data = f.read()
+
+f.close()
+
+# OK
+with tempfile.TemporaryFile() as f:
+    data = f.read()
+
+# OK
+with tarfile.open("foo.tar") as f:
+    data = f.add("foo.txt")
+
+# OK
+with tarfile.TarFile("foo.tar") as f:
+    data = f.add("foo.txt")
+
+# OK
+with tarfile.TarFile("foo.tar").open() as f:
+    data = f.add("foo.txt")
+
+# OK
+with zipfile.ZipFile("foo.zip") as f:
+    data = f.read("foo.txt")
+
+# OK
+with zipfile.ZipFile("foo.zip").open("foo.txt") as f:
+    data = f.read()
+
+# OK
+with zipfile.ZipFile("foo.zip") as zf:
+    with zf.open("foo.txt") as f:
+        data = f.read()
+
+# OK
+with io.open("foo.txt") as f:
+    data = f.read()
+
+# OK
+with io.open_code("foo.txt") as f:
+    data = f.read()
+
+# OK
+with codecs.open("foo.txt") as f:
+    data = f.read()
+
+# OK
+with bz2.open("foo.txt") as f:
+    data = f.read()
+
+# OK
+with gzip.open("foo.txt") as f:
+    data = f.read()
+
+# OK
+with dbm.open("foo.db") as f:
+    data = f.get("foo")
+
+# OK
+with dbm.gnu.open("foo.db") as f:
+    data = f.get("foo")
+
+# OK
+with dbm.ndbm.open("foo.db") as f:
+    data = f.get("foo")
+
+# OK
+with dbm.dumb.open("foo.db") as f:
+    data = f.get("foo")
+
+# OK
+with lzma.open("foo.xz") as f:
+    data = f.read()
+
+# OK
+with lzma.LZMAFile("foo.xz") as f:
+    data = f.read()
+
+# OK
+with shelve.open("foo.db") as f:
+    data = f["foo"]
+
+# OK
+with tokenize.open("foo.py") as f:
+    data = f.read()
+
+# OK
+with wave.open("foo.wav") as f:
+    data = f.readframes(1024)
+
+# OK
+with tarfile.TarFile.taropen("foo.tar") as f:
+    data = f.add("foo.txt")
+
+# OK
+with fileinput.input("foo.txt") as f:
+    data = f.readline()
+
+# OK
+with fileinput.FileInput("foo.txt") as f:
+    data = f.readline()
+
+# OK (quick one-liner to clear file contents)
+tempfile.NamedTemporaryFile().close()
+tempfile.TemporaryFile().close()
+tempfile.SpooledTemporaryFile().close()
+tarfile.open("foo.tar").close()
+tarfile.TarFile("foo.tar").close()
+tarfile.TarFile("foo.tar").open().close()
+tarfile.TarFile.open("foo.tar").close()
+zipfile.ZipFile("foo.zip").close()
+zipfile.ZipFile("foo.zip").open("foo.txt").close()
+io.open("foo.txt").close()
+io.open_code("foo.txt").close()
+codecs.open("foo.txt").close()
+bz2.open("foo.txt").close()
+gzip.open("foo.txt").close()
+dbm.open("foo.db").close()
+dbm.gnu.open("foo.db").close()
+dbm.ndbm.open("foo.db").close()
+dbm.dumb.open("foo.db").close()
+lzma.open("foo.xz").close()
+lzma.LZMAFile("foo.xz").close()
+shelve.open("foo.db").close()
+tokenize.open("foo.py").close()
+wave.open("foo.wav").close()
+tarfile.TarFile.taropen("foo.tar").close()
+fileinput.input("foo.txt").close()
+fileinput.FileInput("foo.txt").close()
+
+def aliased():
+    from shelve import open as open_shelf
+    x = open_shelf("foo.dbm")
+    x.close()
+
+    from tarfile import TarFile as TF
+    f = TF("foo").open()
+    f.close()
--- a/crates/ruff_linter/resources/test/fixtures/ruff/RUF032.py
+++ b/crates/ruff_linter/resources/test/fixtures/ruff/RUF032.py
@@ -0,0 +1,120 @@
+import decimal
+
+# Tests with fully qualified import
+decimal.Decimal(0)
+
+decimal.Decimal(0.0)  # Should error
+
+decimal.Decimal("0.0")
+
+decimal.Decimal(10)
+
+decimal.Decimal(10.0)  # Should error
+
+decimal.Decimal("10.0")
+
+decimal.Decimal(-10)
+
+decimal.Decimal(-10.0)  # Should error
+
+decimal.Decimal("-10.0")
+
+a = 10.0
+
+decimal.Decimal(a)
+
+
+# Tests with relative import
+from decimal import Decimal
+
+
+val = Decimal(0)
+
+val = Decimal(0.0)  # Should error
+
+val = Decimal("0.0")
+
+val = Decimal(10)
+
+val = Decimal(10.0)  # Should error
+
+val = Decimal("10.0")
+
+val = Decimal(-10)
+
+val = Decimal(-10.0)  # Should error
+
+val = Decimal("-10.0")
+
+a = 10.0
+
+val = Decimal(a)
+
+
+# Tests with shadowed name
+class Decimal():
+    value: float | int | str
+
+    def __init__(self, value: float | int | str) -> None:
+        self.value = value
+
+
+val = Decimal(0.0)
+
+val = Decimal("0.0")
+
+val = Decimal(10.0)
+
+val = Decimal("10.0")
+
+val = Decimal(-10.0)
+
+val = Decimal("-10.0")
+
+a = 10.0
+
+val = Decimal(a)
+
+
+# Retest with fully qualified import
+
+val = decimal.Decimal(0.0)  # Should error
+
+val = decimal.Decimal("0.0")
+
+val = decimal.Decimal(10.0)  # Should error
+
+val = decimal.Decimal("10.0")
+
+val = decimal.Decimal(-10.0)  # Should error
+
+val = decimal.Decimal("-10.0")
+
+a = 10.0
+
+val = decimal.Decimal(a)
+
+
+class decimal():
+    class Decimal():
+        value: float | int | str
+
+        def __init__(self, value: float | int | str) -> None:
+            self.value = value
+
+
+val = decimal.Decimal(0.0)
+
+val = decimal.Decimal("0.0")
+
+val = decimal.Decimal(10.0)
+
+val = decimal.Decimal("10.0")
+
+val = decimal.Decimal(-10.0)
+
+val = decimal.Decimal("-10.0")
+
+a = 10.0
+
+val = decimal.Decimal(a)
--- a/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/expression.rs
@@ -883,7 +883,7 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
                flake8_simplify::rules::use_capital_environment_variables(checker, expr);
            }
            if checker.enabled(Rule::OpenFileWithContextHandler) {
-                flake8_simplify::rules::open_file_with_context_handler(checker, func);
+                flake8_simplify::rules::open_file_with_context_handler(checker, call);
            }
            if checker.enabled(Rule::DictGetWithNoneDefault) {
                flake8_simplify::rules::dict_get_with_none_default(checker, expr);
@@ -1011,6 +1011,9 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
            if checker.enabled(Rule::UnnecessaryIterableAllocationForFirstElement) {
                ruff::rules::unnecessary_iterable_allocation_for_first_element(checker, expr);
            }
+            if checker.enabled(Rule::DecimalFromFloatLiteral) {
+                ruff::rules::decimal_from_float_literal_syntax(checker, call);
+            }
            if checker.enabled(Rule::IntOnSlicedStr) {
                refurb::rules::int_on_sliced_str(checker, call);
            }
--- a/crates/ruff_linter/src/codes.rs
+++ b/crates/ruff_linter/src/codes.rs
@@ -959,6 +959,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
        (Ruff, "029") => (RuleGroup::Preview, rules::ruff::rules::UnusedAsync),
        (Ruff, "030") => (RuleGroup::Preview, rules::ruff::rules::AssertWithPrintMessage),
        (Ruff, "031") => (RuleGroup::Preview, rules::ruff::rules::IncorrectlyParenthesizedTupleInSubscript),
+        (Ruff, "032") => (RuleGroup::Preview, rules::ruff::rules::DecimalFromFloatLiteral),
        (Ruff, "100") => (RuleGroup::Stable, rules::ruff::rules::UnusedNOQA),
        (Ruff, "101") => (RuleGroup::Stable, rules::ruff::rules::RedirectedNOQA),

--- a/crates/ruff_linter/src/message/grouped.rs
+++ b/crates/ruff_linter/src/message/grouped.rs
@@ -9,7 +9,7 @@ use ruff_source_file::OneIndexed;

 use crate::fs::relativize_path;
 use crate::message::diff::calculate_print_width;
-use crate::message::text::{MessageCodeFrame, RuleCodeAndBody};
+use crate::message::text::RuleCodeAndBody;
 use crate::message::{
    group_messages_by_filename, Emitter, EmitterContext, Message, MessageWithLocation,
 };
@@ -154,16 +154,16 @@ impl Display for DisplayGroupedMessage<'_> {
        )?;

        if self.show_source {
-            use std::fmt::Write;
-            let mut padded = PadAdapter::new(f);
-            writeln!(
-                padded,
-                "{}",
-                MessageCodeFrame {
-                    message,
-                    notebook_index: self.notebook_index
-                }
-            )?;
+            // use std::fmt::Write;
+            // let mut padded = PadAdapter::new(f);
+            // writeln!(
+            //     padded,
+            //     "{}",
+            //     MessageCodeFrame {
+            //         message,
+            //         notebook_index: self.notebook_index
+            //     }
+            // )?;
        }

        Ok(())
--- a/crates/ruff_linter/src/message/mod.rs
+++ b/crates/ruff_linter/src/message/mod.rs
@@ -112,10 +112,7 @@ impl Message {
            .map_or(TextSize::new(0), TextLen::text_len);

        Message::SyntaxError(SyntaxErrorMessage {
-            message: format!(
-                "SyntaxError: {}",
-                DisplayParseErrorType::new(&parse_error.error)
-            ),
+            message: DisplayParseErrorType::new(&parse_error.error).to_string(),
            range: TextRange::at(parse_error.location.start(), len),
            file,
        })
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessageazuretestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessageazuretestssyntax_errors.snap
@@ -2,5 +2,5 @@
 source: crates/ruff_linter/src/message/azure.rs
 expression: content
 ---
-##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=1;columnnumber=15;]SyntaxError: Expected one or more symbol names after import
-##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=3;columnnumber=12;]SyntaxError: Expected ')', found newline
+##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=1;columnnumber=15;]Expected one or more symbol names after import
+##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=3;columnnumber=12;]Expected ')', found newline
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegithubtestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegithubtestssyntax_errors.snap
@@ -2,5 +2,5 @@
 source: crates/ruff_linter/src/message/github.rs
 expression: content
 ---
-::error title=Ruff,file=syntax_errors.py,line=1,col=15,endLine=2,endColumn=1::syntax_errors.py:1:15: SyntaxError: Expected one or more symbol names after import
-::error title=Ruff,file=syntax_errors.py,line=3,col=12,endLine=4,endColumn=1::syntax_errors.py:3:12: SyntaxError: Expected ')', found newline
+::error title=Ruff,file=syntax_errors.py,line=1,col=15,endLine=2,endColumn=1::syntax_errors.py:1:15: Expected one or more symbol names after import
+::error title=Ruff,file=syntax_errors.py,line=3,col=12,endLine=4,endColumn=1::syntax_errors.py:3:12: Expected ')', found newline
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegitlabtestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegitlabtestssyntax_errors.snap
@@ -4,7 +4,7 @@ expression: redact_fingerprint(&content)
 ---
 [
  {
-    "description": "SyntaxError: Expected one or more symbol names after import",
+    "description": "Expected one or more symbol names after import",
    "fingerprint": "<redacted>",
    "location": {
      "lines": {
@@ -16,7 +16,7 @@ expression: redact_fingerprint(&content)
    "severity": "major"
  },
  {
-    "description": "SyntaxError: Expected ')', found newline",
+    "description": "Expected ')', found newline",
    "fingerprint": "<redacted>",
    "location": {
      "lines": {
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsdefault.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsdefault.snap
@@ -3,10 +3,8 @@ source: crates/ruff_linter/src/message/grouped.rs
 expression: content
 ---
 fib.py:
-  1:8 F401 `os` imported but unused
-  6:5 F841 Local variable `x` is assigned to but never used
+  1:8 `os` imported but unused
+  6:5 Local variable `x` is assigned to but never used

 undef.py:
-  1:4 F821 Undefined name `a`
-
-
+  1:4 Undefined name `a`
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsfix_status.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsfix_status.snap
@@ -3,29 +3,7 @@ source: crates/ruff_linter/src/message/grouped.rs
 expression: content
 ---
 fib.py:
-  1:8 F401 `os` imported but unused
-    |
-  1 | import os
-    |        ^^ F401
-    |
-    = help: Remove unused import: `os`
-  
-  6:5 F841 Local variable `x` is assigned to but never used
-    |
-  4 | def fibonacci(n):
-  5 |     """Compute the nth number in the Fibonacci sequence."""
-  6 |     x = 1
-    |     ^ F841
-  7 |     if n == 0:
-  8 |         return 0
-    |
-    = help: Remove assignment to unused variable `x`
-  
+  1:8 `os` imported but unused
+  6:5 Local variable `x` is assigned to but never used
 undef.py:
-  1:4 F821 Undefined name `a`
-    |
-  1 | if a == 1: pass
-    |    ^ F821
-    |
-  
-
+  1:4 Undefined name `a`
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsfix_status_unsafe.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsfix_status_unsafe.snap
@@ -3,29 +3,7 @@ source: crates/ruff_linter/src/message/grouped.rs
 expression: content
 ---
 fib.py:
-  1:8 F401 [*] `os` imported but unused
-    |
-  1 | import os
-    |        ^^ F401
-    |
-    = help: Remove unused import: `os`
-  
-  6:5 F841 [*] Local variable `x` is assigned to but never used
-    |
-  4 | def fibonacci(n):
-  5 |     """Compute the nth number in the Fibonacci sequence."""
-  6 |     x = 1
-    |     ^ F841
-  7 |     if n == 0:
-  8 |         return 0
-    |
-    = help: Remove assignment to unused variable `x`
-  
+  1:8 [*] `os` imported but unused
+  6:5 [*] Local variable `x` is assigned to but never used
 undef.py:
-  1:4 F821 Undefined name `a`
-    |
-  1 | if a == 1: pass
-    |    ^ F821
-    |
-  
-
+  1:4 Undefined name `a`
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsshow_source.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestsshow_source.snap
@@ -3,29 +3,7 @@ source: crates/ruff_linter/src/message/grouped.rs
 expression: content
 ---
 fib.py:
-  1:8 F401 `os` imported but unused
-    |
-  1 | import os
-    |        ^^ F401
-    |
-    = help: Remove unused import: `os`
-  
-  6:5 F841 Local variable `x` is assigned to but never used
-    |
-  4 | def fibonacci(n):
-  5 |     """Compute the nth number in the Fibonacci sequence."""
-  6 |     x = 1
-    |     ^ F841
-  7 |     if n == 0:
-  8 |         return 0
-    |
-    = help: Remove assignment to unused variable `x`
-  
+  1:8 `os` imported but unused
+  6:5 Local variable `x` is assigned to but never used
 undef.py:
-  1:4 F821 Undefined name `a`
-    |
-  1 | if a == 1: pass
-    |    ^ F821
-    |
-  
-
+  1:4 Undefined name `a`
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagegroupedtestssyntax_errors.snap
@@ -3,5 +3,5 @@ source: crates/ruff_linter/src/message/grouped.rs
 expression: content
 ---
 syntax_errors.py:
-  1:15 SyntaxError: Expected one or more symbol names after import
-  3:12 SyntaxError: Expected ')', found newline
+  1:15 Expected one or more symbol names after import
+  3:12 Expected ')', found newline
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejsontestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejsontestssyntax_errors.snap
@@ -16,7 +16,7 @@ expression: content
      "column": 15,
      "row": 1
    },
-    "message": "SyntaxError: Expected one or more symbol names after import",
+    "message": "Expected one or more symbol names after import",
    "noqa_row": null,
    "url": null
  },
@@ -33,7 +33,7 @@ expression: content
      "column": 12,
      "row": 3
    },
-    "message": "SyntaxError: Expected ')', found newline",
+    "message": "Expected ')', found newline",
    "noqa_row": null,
    "url": null
  }
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejson_linestestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejson_linestestssyntax_errors.snap
@@ -2,5 +2,5 @@
 source: crates/ruff_linter/src/message/json_lines.rs
 expression: content
 ---
-{"cell":null,"code":null,"end_location":{"column":1,"row":2},"filename":"syntax_errors.py","fix":null,"location":{"column":15,"row":1},"message":"SyntaxError: Expected one or more symbol names after import","noqa_row":null,"url":null}
-{"cell":null,"code":null,"end_location":{"column":1,"row":4},"filename":"syntax_errors.py","fix":null,"location":{"column":12,"row":3},"message":"SyntaxError: Expected ')', found newline","noqa_row":null,"url":null}
+{"cell":null,"code":null,"end_location":{"column":1,"row":2},"filename":"syntax_errors.py","fix":null,"location":{"column":15,"row":1},"message":"Expected one or more symbol names after import","noqa_row":null,"url":null}
+{"cell":null,"code":null,"end_location":{"column":1,"row":4},"filename":"syntax_errors.py","fix":null,"location":{"column":12,"row":3},"message":"Expected ')', found newline","noqa_row":null,"url":null}
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejunittestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagejunittestssyntax_errors.snap
@@ -6,10 +6,10 @@ expression: content
 <testsuites name="ruff" tests="2" failures="2" errors="0">
    <testsuite name="syntax_errors.py" tests="2" disabled="0" errors="0" failures="2" package="org.ruff">
        <testcase name="org.ruff" classname="syntax_errors" line="1" column="15">
-            <failure message="SyntaxError: Expected one or more symbol names after import">line 1, col 15, SyntaxError: Expected one or more symbol names after import</failure>
+            <failure message="Expected one or more symbol names after import">line 1, col 15, Expected one or more symbol names after import</failure>
        </testcase>
        <testcase name="org.ruff" classname="syntax_errors" line="3" column="12">
-            <failure message="SyntaxError: Expected &apos;)&apos;, found newline">line 3, col 12, SyntaxError: Expected &apos;)&apos;, found newline</failure>
+            <failure message="Expected &apos;)&apos;, found newline">line 3, col 12, Expected &apos;)&apos;, found newline</failure>
        </testcase>
    </testsuite>
 </testsuites>
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagepylinttestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagepylinttestssyntax_errors.snap
@@ -2,5 +2,5 @@
 source: crates/ruff_linter/src/message/pylint.rs
 expression: content
 ---
-syntax_errors.py:1: SyntaxError: Expected one or more symbol names after import
-syntax_errors.py:3: SyntaxError: Expected ')', found newline
+syntax_errors.py:1: Expected one or more symbol names after import
+syntax_errors.py:3: Expected ')', found newline
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagerdjsontestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagerdjsontestssyntax_errors.snap
@@ -22,7 +22,7 @@ expression: content
          }
        }
      },
-      "message": "SyntaxError: Expected one or more symbol names after import"
+      "message": "Expected one or more symbol names after import"
    },
    {
      "code": {
@@ -42,7 +42,7 @@ expression: content
          }
        }
      },
-      "message": "SyntaxError: Expected ')', found newline"
+      "message": "Expected ')', found newline"
    }
  ],
  "severity": "warning",
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsdefault.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsdefault.snap
@@ -2,28 +2,30 @@
 source: crates/ruff_linter/src/message/text.rs
 expression: content
 ---
-fib.py:1:8: F401 `os` imported but unused
+error[F401]: 1:8: `os` imported but unused
+
+ --> fib.py:1:8
  |
 1 | import os
-  |        ^^ F401
+  |        ^^
  |
  = help: Remove unused import: `os`
+error[F841]: 6:5: Local variable `x` is assigned to but never used

-fib.py:6:5: F841 Local variable `x` is assigned to but never used
+ --> fib.py:6:5
  |
 4 | def fibonacci(n):
 5 |     """Compute the nth number in the Fibonacci sequence."""
 6 |     x = 1
-  |     ^ F841
+  |     ^
 7 |     if n == 0:
 8 |         return 0
  |
  = help: Remove assignment to unused variable `x`
+error[F821]: 1:4: Undefined name `a`

-undef.py:1:4: F821 Undefined name `a`
+ --> undef.py:1:4
  |
 1 | if a == 1: pass
-  |    ^ F821
+  |    ^
  |
-
-
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsfix_status.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsfix_status.snap
@@ -2,28 +2,30 @@
 source: crates/ruff_linter/src/message/text.rs
 expression: content
 ---
-fib.py:1:8: F401 `os` imported but unused
+error[F401]: 1:8: `os` imported but unused
+
+ --> fib.py:1:8
  |
 1 | import os
-  |        ^^ F401
+  |        ^^
  |
  = help: Remove unused import: `os`
+error[F841]: 6:5: Local variable `x` is assigned to but never used

-fib.py:6:5: F841 Local variable `x` is assigned to but never used
+ --> fib.py:6:5
  |
 4 | def fibonacci(n):
 5 |     """Compute the nth number in the Fibonacci sequence."""
 6 |     x = 1
-  |     ^ F841
+  |     ^
 7 |     if n == 0:
 8 |         return 0
  |
  = help: Remove assignment to unused variable `x`
+error[F821]: 1:4: Undefined name `a`

-undef.py:1:4: F821 Undefined name `a`
+ --> undef.py:1:4
  |
 1 | if a == 1: pass
-  |    ^ F821
+  |    ^
  |
-
-
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsfix_status_unsafe.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsfix_status_unsafe.snap
@@ -2,28 +2,30 @@
 source: crates/ruff_linter/src/message/text.rs
 expression: content
 ---
-fib.py:1:8: F401 [*] `os` imported but unused
+error[F401]: 1:8: [*] `os` imported but unused
+
+ --> fib.py:1:8
  |
 1 | import os
-  |        ^^ F401
+  |        ^^
  |
  = help: Remove unused import: `os`
+error[F841]: 6:5: [*] Local variable `x` is assigned to but never used

-fib.py:6:5: F841 [*] Local variable `x` is assigned to but never used
+ --> fib.py:6:5
  |
 4 | def fibonacci(n):
 5 |     """Compute the nth number in the Fibonacci sequence."""
 6 |     x = 1
-  |     ^ F841
+  |     ^
 7 |     if n == 0:
 8 |         return 0
  |
  = help: Remove assignment to unused variable `x`
+error[F821]: 1:4: Undefined name `a`

-undef.py:1:4: F821 Undefined name `a`
+ --> undef.py:1:4
  |
 1 | if a == 1: pass
-  |    ^ F821
+  |    ^
  |
-
-
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsnotebook_output.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestsnotebook_output.snap
@@ -2,31 +2,33 @@
 source: crates/ruff_linter/src/message/text.rs
 expression: content
 ---
-notebook.ipynb:cell 1:2:8: F401 [*] `os` imported but unused
+error[F401]: cell 1:2:8: [*] `os` imported but unused
+
+ --> notebook.ipynb:2:8
  |
 1 | # cell 1
 2 | import os
-  |        ^^ F401
+  |        ^^
  |
  = help: Remove unused import: `os`
+error[F401]: cell 2:2:8: [*] `math` imported but unused

-notebook.ipynb:cell 2:2:8: F401 [*] `math` imported but unused
+ --> notebook.ipynb:2:8
  |
 1 | # cell 2
 2 | import math
-  |        ^^^^ F401
+  |        ^^^^
 3 | 
 4 | print('hello world')
  |
  = help: Remove unused import: `math`
+error[F841]: cell 3:4:5: [*] Local variable `x` is assigned to but never used

-notebook.ipynb:cell 3:4:5: F841 [*] Local variable `x` is assigned to but never used
+ --> notebook.ipynb:4:5
  |
 2 | def foo():
 3 |     print()
 4 |     x = 1
-  |     ^ F841
+  |     ^
  |
  = help: Remove assignment to unused variable `x`
-
-
--- a/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestssyntax_errors.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_lintermessagetexttestssyntax_errors.snap
@@ -2,7 +2,9 @@
 source: crates/ruff_linter/src/message/text.rs
 expression: content
 ---
-syntax_errors.py:1:15: SyntaxError: Expected one or more symbol names after import
+error[syntax-error]: 1:15: Expected one or more symbol names after import
+
+ --> syntax_errors.py:1:15
  |
 1 | from os import
  |               ^
@@ -10,8 +12,9 @@ syntax_errors.py:1:15: SyntaxError: Expected one or more symbol names after impo
 3 | if call(foo
 4 |     def bar():
  |
+error[syntax-error]: 3:12: Expected ')', found newline

-syntax_errors.py:3:12: SyntaxError: Expected ')', found newline
+ --> syntax_errors.py:3:12
  |
 1 | from os import
 2 | 
--- a/crates/ruff_linter/src/message/text.rs
+++ b/crates/ruff_linter/src/message/text.rs
@@ -1,12 +1,11 @@
 use std::borrow::Cow;
+use std::fmt::Write as _;
 use std::fmt::{Display, Formatter};
 use std::io::Write;

-use annotate_snippets::display_list::{DisplayList, FormatOptions};
-use annotate_snippets::snippet::{Annotation, AnnotationType, Slice, Snippet, SourceAnnotation};
+use annotate_snippets::{Level, Renderer, Snippet};
 use bitflags::bitflags;
 use colored::Colorize;
-
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::{OneIndexed, SourceLocation};
 use ruff_text_size::{Ranged, TextRange, TextSize};
@@ -71,20 +70,16 @@ impl Emitter for TextEmitter {
        context: &EmitterContext,
    ) -> anyhow::Result<()> {
        for message in messages {
-            write!(
-                writer,
-                "{path}{sep}",
-                path = relativize_path(message.filename()).bold(),
-                sep = ":".cyan(),
-            )?;
+            let mut title = String::new();

            let start_location = message.compute_start_location();
            let notebook_index = context.notebook_index(message.filename());

            // Check if we're working on a jupyter notebook and translate positions with cell accordingly
+            // TODO: Only append location to title if there are no snippets
            let diagnostic_location = if let Some(notebook_index) = notebook_index {
                write!(
-                    writer,
+                    title,
                    "cell {cell}{sep}",
                    cell = notebook_index
                        .cell(start_location.row)
@@ -103,7 +98,7 @@ impl Emitter for TextEmitter {
            };

            writeln!(
-                writer,
+                title,
                "{row}{sep}{col}{sep} {code_and_body}",
                row = diagnostic_location.row,
                col = diagnostic_location.column,
@@ -115,19 +110,39 @@ impl Emitter for TextEmitter {
                }
            )?;

-            if self.flags.intersects(EmitterFlags::SHOW_SOURCE) {
-                // The `0..0` range is used to highlight file-level diagnostics.
-                if message.range() != TextRange::default() {
-                    writeln!(
-                        writer,
-                        "{}",
-                        MessageCodeFrame {
-                            message,
-                            notebook_index
-                        }
-                    )?;
+            let code = message
+                .rule()
+                .map(|rule| rule.noqa_code().to_string())
+                .unwrap_or_else(|| "syntax-error".to_string());
+            let mut snippet_message = Level::Error.title(&title).id(&code);
+
+            // The `0..0` range is used to highlight file-level diagnostics.
+            let (code_frame, advise) = if self.flags.intersects(EmitterFlags::SHOW_SOURCE)
+                && message.range() != TextRange::default()
+            {
+                (
+                    Some(CodeFrameSnippet::new(message, notebook_index)),
+                    create_suggestion_footer(&message),
+                )
+            } else {
+                (None, None)
+            };
+
+            snippet_message = snippet_message
+                .snippets(code_frame.as_ref().map(|snippet| snippet.as_snippet()))
+                .footers(advise);
+
+            let renderer = if cfg!(not(test)) {
+                if colored::control::SHOULD_COLORIZE.should_colorize() {
+                    Renderer::styled()
+                } else {
+                    Renderer::plain()
                }
-            }
+            } else {
+                Renderer::plain()
+            };
+
+            writeln!(writer, "{}", renderer.render(snippet_message))?;

            if self.flags.intersects(EmitterFlags::SHOW_FIX_DIFF) {
                if let Some(diff) = Diff::from_message(message) {
@@ -152,9 +167,6 @@ impl Display for RuleCodeAndBody<'_> {
            if let Some(fix) = self.message.fix() {
                // Do not display an indicator for unapplicable fixes
                if fix.applies(self.unsafe_fixes.required_applicability()) {
-                    if let Some(rule) = self.message.rule() {
-                        write!(f, "{} ", rule.noqa_code().to_string().red().bold())?;
-                    }
                    return write!(
                        f,
                        "{fix}{body}",
@@ -165,45 +177,26 @@ impl Display for RuleCodeAndBody<'_> {
            }
        };

-        if let Some(rule) = self.message.rule() {
-            write!(
-                f,
-                "{code} {body}",
-                code = rule.noqa_code().to_string().red().bold(),
-                body = self.message.body(),
-            )
-        } else {
-            f.write_str(self.message.body())
-        }
+        f.write_str(self.message.body())
    }
 }

-pub(super) struct MessageCodeFrame<'a> {
-    pub(crate) message: &'a Message,
-    pub(crate) notebook_index: Option<&'a NotebookIndex>,
+struct CodeFrameSnippet<'a> {
+    pub(crate) source: SourceCode<'a>,
+    file_name: String,
+    line_start: OneIndexed,
 }

-impl Display for MessageCodeFrame<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        let suggestion = self.message.suggestion();
-        let footer = if suggestion.is_some() {
-            vec![Annotation {
-                id: None,
-                label: suggestion,
-                annotation_type: AnnotationType::Help,
-            }]
-        } else {
-            Vec::new()
-        };
+impl<'a> CodeFrameSnippet<'a> {
+    fn new(message: &'a Message, notebook_index: Option<&NotebookIndex>) -> Self {
+        let source_code = message.source_file().to_source_code();

-        let source_code = self.message.source_file().to_source_code();
-
-        let content_start_index = source_code.line_index(self.message.start());
+        let content_start_index = source_code.line_index(message.start());
        let mut start_index = content_start_index.saturating_sub(2);

        // If we're working with a Jupyter Notebook, skip the lines which are
        // outside of the cell containing the diagnostic.
-        if let Some(index) = self.notebook_index {
+        if let Some(index) = notebook_index {
            let content_start_cell = index.cell(content_start_index).unwrap_or(OneIndexed::MIN);
            while start_index < content_start_index {
                if index.cell(start_index).unwrap_or(OneIndexed::MIN) == content_start_cell {
@@ -221,14 +214,14 @@ impl Display for MessageCodeFrame<'_> {
            start_index = start_index.saturating_add(1);
        }

-        let content_end_index = source_code.line_index(self.message.end());
+        let content_end_index = source_code.line_index(message.end());
        let mut end_index = content_end_index
            .saturating_add(2)
            .min(OneIndexed::from_zero_indexed(source_code.line_count()));

        // If we're working with a Jupyter Notebook, skip the lines which are
        // outside of the cell containing the diagnostic.
-        if let Some(index) = self.notebook_index {
+        if let Some(index) = notebook_index {
            let content_end_cell = index.cell(content_end_index).unwrap_or(OneIndexed::MIN);
            while end_index > content_end_index {
                if index.cell(end_index).unwrap_or(OneIndexed::MIN) == content_end_cell {
@@ -252,60 +245,48 @@ impl Display for MessageCodeFrame<'_> {

        let source = replace_whitespace(
            source_code.slice(TextRange::new(start_offset, end_offset)),
-            self.message.range() - start_offset,
+            message.range() - start_offset,
        );

-        let source_text = source.text.show_nonprinting();
+        // TODO: Is it safe to keep the same annotation range after
+        // TODO handle show nonpritning
+        // showing nonprinting/replacing whitespace?
+        // let source = SourceCode {
+        //     text: source.text.show_nonprinting(),
+        //     annotation_range: source.annotation_range,
+        // };

-        let start_char = source.text[TextRange::up_to(source.annotation_range.start())]
-            .chars()
-            .count();
-
-        let char_length = source.text[source.annotation_range].chars().count();
-
-        let label = self
-            .message
-            .rule()
-            .map_or_else(String::new, |rule| rule.noqa_code().to_string());
-
-        let snippet = Snippet {
-            title: None,
-            slices: vec![Slice {
-                source: &source_text,
-                line_start: self.notebook_index.map_or_else(
-                    || start_index.get(),
-                    |notebook_index| {
-                        notebook_index
-                            .cell_row(start_index)
-                            .unwrap_or(OneIndexed::MIN)
-                            .get()
-                    },
-                ),
-                annotations: vec![SourceAnnotation {
-                    label: &label,
-                    annotation_type: AnnotationType::Error,
-                    range: (start_char, start_char + char_length),
-                }],
-                // The origin (file name, line number, and column number) is already encoded
-                // in the `label`.
-                origin: None,
-                fold: false,
-            }],
-            footer,
-            opt: FormatOptions {
-                #[cfg(test)]
-                color: false,
-                #[cfg(not(test))]
-                color: colored::control::SHOULD_COLORIZE.should_colorize(),
-                ..FormatOptions::default()
+        let line_start = notebook_index.map_or_else(
+            || start_index,
+            |notebook_index| {
+                notebook_index
+                    .cell_row(start_index)
+                    .unwrap_or(OneIndexed::MIN)
            },
-        };
+        );

-        writeln!(f, "{message}", message = DisplayList::from(snippet))
+        Self {
+            line_start,
+            source,
+            file_name: relativize_path(message.filename()),
+        }
+    }
+
+    pub(super) fn as_snippet(&self) -> Snippet {
+        Snippet::source(&self.source.text)
+            .origin(&self.file_name)
+            .line_start(self.line_start.get())
+            .annotation(Level::Error.span(self.source.annotation_range.into()))
    }
 }

-fn replace_whitespace(source: &str, annotation_range: TextRange) -> SourceCode {
+fn create_suggestion_footer(message: &Message) -> Option<annotate_snippets::Message> {
+    let suggestion = message.suggestion()?;
+
+    Some(Level::Help.title(suggestion))
+}
+
+fn replace_whitespace<'a>(source: &str, annotation_range: TextRange) -> SourceCode {
    let mut result = String::new();
    let mut last_end = 0;
    let mut range = annotation_range;
--- a/crates/ruff_linter/src/rules/airflow/snapshots/ruff_linterrulesairflowtestsAIR001_AIR001.py.snap
+++ b/crates/ruff_linter/src/rules/airflow/snapshots/ruff_linterrulesairflowtestsAIR001_AIR001.py.snap
@@ -1,22 +1,23 @@
 ---
 source: crates/ruff_linter/src/rules/airflow/mod.rs
 ---
-AIR001.py:11:1: AIR001 Task variable name should match the `task_id`: "my_task"
+error[AIR001]: 11:1: Task variable name should match the `task_id`: "my_task"
+
+  --> AIR001.py:10:1
   |
 9 | my_task_2 = PythonOperator(callable=my_callable, task_id="my_task_2")
 10 | 
 11 | incorrect_name = PythonOperator(task_id="my_task")
-   | ^^^^^^^^^^^^^^ AIR001
+   | ^^^^^^^^^^^^^^
 12 | incorrect_name_2 = PythonOperator(callable=my_callable, task_id="my_task_2")
   |
+error[AIR001]: 12:1: Task variable name should match the `task_id`: "my_task_2"

-AIR001.py:12:1: AIR001 Task variable name should match the `task_id`: "my_task_2"
+  --> AIR001.py:11:51
   |
 11 | incorrect_name = PythonOperator(task_id="my_task")
 12 | incorrect_name_2 = PythonOperator(callable=my_callable, task_id="my_task_2")
-   | ^^^^^^^^^^^^^^^^ AIR001
+   | ^^^^^^^^^^^^^^^^
 13 | 
 14 | from my_module import MyClass
   |
-
-
--- a/crates/ruff_linter/src/rules/eradicate/snapshots/ruff_linterruleseradicatetestsERA001_ERA001.py.snap
+++ b/crates/ruff_linter/src/rules/eradicate/snapshots/ruff_linterruleseradicatetestsERA001_ERA001.py.snap
@@ -1,31 +1,33 @@
 ---
 source: crates/ruff_linter/src/rules/eradicate/mod.rs
 ---
-ERA001.py:1:1: ERA001 Found commented-out code
+error[ERA001]: 1:1: Found commented-out code
+
+ --> ERA001.py:1:1
  |
 1 | #import os
-  | ^^^^^^^^^^ ERA001
+  | ^^^^^^^^^^
 2 | # from foo import junk
 3 | #a = 3
  |
  = help: Remove commented-out code
-
 ℹ Display-only fix
 1   |-#import os
 2 1 | # from foo import junk
 3 2 | #a = 3
 4 3 | a = 4

-ERA001.py:2:1: ERA001 Found commented-out code
+error[ERA001]: 2:1: Found commented-out code
+
+ --> ERA001.py:1:11
  |
 1 | #import os
 2 | # from foo import junk
-  | ^^^^^^^^^^^^^^^^^^^^^^ ERA001
+  | ^^^^^^^^^^^^^^^^^^^^^^
 3 | #a = 3
 4 | a = 4
  |
  = help: Remove commented-out code
-
 ℹ Display-only fix
 1 1 | #import os
 2   |-# from foo import junk
@@ -33,17 +35,18 @@ ERA001.py:2:1: ERA001 Found commented-out code
 4 3 | a = 4
 5 4 | #foo(1, 2, 3)

-ERA001.py:3:1: ERA001 Found commented-out code
+error[ERA001]: 3:1: Found commented-out code
+
+ --> ERA001.py:2:23
  |
 1 | #import os
 2 | # from foo import junk
 3 | #a = 3
-  | ^^^^^^ ERA001
+  | ^^^^^^
 4 | a = 4
 5 | #foo(1, 2, 3)
  |
  = help: Remove commented-out code
-
 ℹ Display-only fix
 1 1 | #import os
 2 2 | # from foo import junk
@@ -52,17 +55,18 @@ ERA001.py:3:1: ERA001 Found commented-out code
 5 4 | #foo(1, 2, 3)
 6 5 | 

-ERA001.py:5:1: ERA001 Found commented-out code
+error[ERA001]: 5:1: Found commented-out code
+
+ --> ERA001.py:4:6
  |
 3 | #a = 3
 4 | a = 4
 5 | #foo(1, 2, 3)
-  | ^^^^^^^^^^^^^ ERA001
+  | ^^^^^^^^^^^^^
 6 | 
 7 | def foo(x, y, z):
  |
  = help: Remove commented-out code
-
 ℹ Display-only fix
 2 2 | # from foo import junk
 3 3 | #a = 3
@@ -72,16 +76,17 @@ ERA001.py:5:1: ERA001 Found commented-out code
 7 6 | def foo(x, y, z):
 8 7 |     content = 1 # print('hello')

-ERA001.py:13:5: ERA001 Found commented-out code
+error[ERA001]: 13:5: Found commented-out code
+
+  --> ERA001.py:13:5
   |
 11 |     # This is a real comment.
 12 |     # # This is a (nested) comment.
 13 |     #return True
-   |     ^^^^^^^^^^^^ ERA001
+   |     ^^^^^^^^^^^^
 14 |     return False
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 10 10 | 
 11 11 |     # This is a real comment.
@@ -91,15 +96,16 @@ ERA001.py:13:5: ERA001 Found commented-out code
 15 14 | 
 16 15 | #import os  # noqa: ERA001

-ERA001.py:21:5: ERA001 Found commented-out code
+error[ERA001]: 21:5: Found commented-out code
+
+  --> ERA001.py:21:5
   |
 19 | class A():
 20 |     pass
 21 |     # b = c
-   |     ^^^^^^^ ERA001
+   |     ^^^^^^^
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 18 18 | 
 19 19 | class A():
@@ -109,17 +115,18 @@ ERA001.py:21:5: ERA001 Found commented-out code
 23 22 | 
 24 23 | dictionary = {

-ERA001.py:26:5: ERA001 Found commented-out code
+error[ERA001]: 26:5: Found commented-out code
+
+  --> ERA001.py:26:5
   |
 24 | dictionary = {
 25 |     # "key1": 123,  # noqa: ERA001
 26 |     # "key2": 456,
-   |     ^^^^^^^^^^^^^^ ERA001
+   |     ^^^^^^^^^^^^^^
 27 |     # "key3": 789,  # test
 28 | }
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 23 23 | 
 24 24 | dictionary = {
@@ -129,16 +136,17 @@ ERA001.py:26:5: ERA001 Found commented-out code
 28 27 | }
 29 28 | 

-ERA001.py:27:5: ERA001 Found commented-out code
+error[ERA001]: 27:5: Found commented-out code
+
+  --> ERA001.py:27:5
   |
 25 |     # "key1": 123,  # noqa: ERA001
 26 |     # "key2": 456,
 27 |     # "key3": 789,  # test
-   |     ^^^^^^^^^^^^^^^^^^^^^^ ERA001
+   |     ^^^^^^^^^^^^^^^^^^^^^^
 28 | }
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 24 24 | dictionary = {
 25 25 |     # "key1": 123,  # noqa: ERA001
@@ -148,17 +156,18 @@ ERA001.py:27:5: ERA001 Found commented-out code
 29 28 | 
 30 29 | #import os  # noqa

-ERA001.py:32:1: ERA001 Found commented-out code
+error[ERA001]: 32:1: Found commented-out code
+
+  --> ERA001.py:31:1
   |
 30 | #import os  # noqa
 31 | 
 32 | # case 1:
-   | ^^^^^^^^^ ERA001
+   | ^^^^^^^^^
 33 | # try:
 34 | # try:  # with comment
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 29 29 | 
 30 30 | #import os  # noqa
@@ -168,16 +177,17 @@ ERA001.py:32:1: ERA001 Found commented-out code
 34 33 | # try:  # with comment
 35 34 | # try: print()

-ERA001.py:33:1: ERA001 Found commented-out code
+error[ERA001]: 33:1: Found commented-out code
+
+  --> ERA001.py:32:10
   |
 32 | # case 1:
 33 | # try:
-   | ^^^^^^ ERA001
+   | ^^^^^^
 34 | # try:  # with comment
 35 | # try: print()
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 30 30 | #import os  # noqa
 31 31 | 
@@ -187,17 +197,18 @@ ERA001.py:33:1: ERA001 Found commented-out code
 35 34 | # try: print()
 36 35 | # except:

-ERA001.py:34:1: ERA001 Found commented-out code
+error[ERA001]: 34:1: Found commented-out code
+
+  --> ERA001.py:33:7
   |
 32 | # case 1:
 33 | # try:
 34 | # try:  # with comment
-   | ^^^^^^^^^^^^^^^^^^^^^^ ERA001
+   | ^^^^^^^^^^^^^^^^^^^^^^
 35 | # try: print()
 36 | # except:
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 31 31 | 
 32 32 | # case 1:
@@ -207,17 +218,18 @@ ERA001.py:34:1: ERA001 Found commented-out code
 36 35 | # except:
 37 36 | # except Foo:

-ERA001.py:35:1: ERA001 Found commented-out code
+error[ERA001]: 35:1: Found commented-out code
+
+  --> ERA001.py:34:23
   |
 33 | # try:
 34 | # try:  # with comment
 35 | # try: print()
-   | ^^^^^^^^^^^^^^ ERA001
+   | ^^^^^^^^^^^^^^
 36 | # except:
 37 | # except Foo:
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 32 32 | # case 1:
 33 33 | # try:
@@ -227,17 +239,18 @@ ERA001.py:35:1: ERA001 Found commented-out code
 37 36 | # except Foo:
 38 37 | # except Exception as e: print(e)

-ERA001.py:36:1: ERA001 Found commented-out code
+error[ERA001]: 36:1: Found commented-out code
+
+  --> ERA001.py:35:15
   |
 34 | # try:  # with comment
 35 | # try: print()
 36 | # except:
-   | ^^^^^^^^^ ERA001
+   | ^^^^^^^^^
 37 | # except Foo:
 38 | # except Exception as e: print(e)
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 33 33 | # try:
 34 34 | # try:  # with comment
@@ -247,16 +260,17 @@ ERA001.py:36:1: ERA001 Found commented-out code
 38 37 | # except Exception as e: print(e)
 39 38 | 

-ERA001.py:37:1: ERA001 Found commented-out code
+error[ERA001]: 37:1: Found commented-out code
+
+  --> ERA001.py:36:10
   |
 35 | # try: print()
 36 | # except:
 37 | # except Foo:
-   | ^^^^^^^^^^^^^ ERA001
+   | ^^^^^^^^^^^^^
 38 | # except Exception as e: print(e)
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 34 34 | # try:  # with comment
 35 35 | # try: print()
@@ -266,15 +280,16 @@ ERA001.py:37:1: ERA001 Found commented-out code
 39 38 | 
 40 39 | 

-ERA001.py:38:1: ERA001 Found commented-out code
+error[ERA001]: 38:1: Found commented-out code
+
+  --> ERA001.py:37:14
   |
 36 | # except:
 37 | # except Foo:
 38 | # except Exception as e: print(e)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ERA001
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 35 35 | # try: print()
 36 36 | # except:
@@ -284,16 +299,17 @@ ERA001.py:38:1: ERA001 Found commented-out code
 40 39 | 
 41 40 | # Script tag without an opening tag (Error)

-ERA001.py:44:1: ERA001 Found commented-out code
+error[ERA001]: 44:1: Found commented-out code
+
+  --> ERA001.py:43:29
   |
 43 | # requires-python = ">=3.11"
 44 | # dependencies = [
-   | ^^^^^^^^^^^^^^^^^^ ERA001
+   | ^^^^^^^^^^^^^^^^^^
 45 | #   "requests<3",
 46 | #   "rich",
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 41 41 | # Script tag without an opening tag (Error)
 42 42 | 
@@ -303,16 +319,17 @@ ERA001.py:44:1: ERA001 Found commented-out code
 46 45 | #   "rich",
 47 46 | # ]

-ERA001.py:47:1: ERA001 Found commented-out code
+error[ERA001]: 47:1: Found commented-out code
+
+  --> ERA001.py:46:12
   |
 45 | #   "requests<3",
 46 | #   "rich",
 47 | # ]
-   | ^^^ ERA001
+   | ^^^
 48 | # ///
   |
   = help: Remove commented-out code
-
 ℹ Display-only fix
 44 44 | # dependencies = [
 45 45 | #   "requests<3",
--- a/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-non-annotated-dependency_FAST002.py.snap
+++ b/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-non-annotated-dependency_FAST002.py.snap
@@ -1,17 +1,18 @@
 ---
 source: crates/ruff_linter/src/rules/fastapi/mod.rs
 ---
-FAST002.py:24:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 24:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:24:5
   |
 22 | @app.get("/items/")
 23 | def get_items(
 24 |     current_user: User = Depends(get_current_user),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 25 |     some_security_param: str = Security(get_oauth2_user),
 26 | ):
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -30,17 +31,18 @@ FAST002.py:24:5: FAST002 [*] FastAPI dependency without `Annotated`
 26 27 | ):
 27 28 |     pass

-FAST002.py:25:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 25:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:25:5
   |
 23 | def get_items(
 24 |     current_user: User = Depends(get_current_user),
 25 |     some_security_param: str = Security(get_oauth2_user),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 26 | ):
 27 |     pass
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -59,17 +61,18 @@ FAST002.py:25:5: FAST002 [*] FastAPI dependency without `Annotated`
 27 28 |     pass
 28 29 | 

-FAST002.py:32:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 32:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:32:5
   |
 30 | @app.post("/stuff/")
 31 | def do_stuff(
 32 |     some_query_param: str | None = Query(default=None),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 33 |     some_path_param: str = Path(),
 34 |     some_body_param: str = Body("foo"),
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -88,17 +91,18 @@ FAST002.py:32:5: FAST002 [*] FastAPI dependency without `Annotated`
 34 35 |     some_body_param: str = Body("foo"),
 35 36 |     some_cookie_param: str = Cookie(),

-FAST002.py:33:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 33:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:33:5
   |
 31 | def do_stuff(
 32 |     some_query_param: str | None = Query(default=None),
 33 |     some_path_param: str = Path(),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 34 |     some_body_param: str = Body("foo"),
 35 |     some_cookie_param: str = Cookie(),
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -117,17 +121,18 @@ FAST002.py:33:5: FAST002 [*] FastAPI dependency without `Annotated`
 35 36 |     some_cookie_param: str = Cookie(),
 36 37 |     some_header_param: int = Header(default=5),

-FAST002.py:34:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 34:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:34:5
   |
 32 |     some_query_param: str | None = Query(default=None),
 33 |     some_path_param: str = Path(),
 34 |     some_body_param: str = Body("foo"),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 35 |     some_cookie_param: str = Cookie(),
 36 |     some_header_param: int = Header(default=5),
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -146,17 +151,18 @@ FAST002.py:34:5: FAST002 [*] FastAPI dependency without `Annotated`
 36 37 |     some_header_param: int = Header(default=5),
 37 38 |     some_file_param: UploadFile = File(),

-FAST002.py:35:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 35:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:35:5
   |
 33 |     some_path_param: str = Path(),
 34 |     some_body_param: str = Body("foo"),
 35 |     some_cookie_param: str = Cookie(),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 36 |     some_header_param: int = Header(default=5),
 37 |     some_file_param: UploadFile = File(),
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -175,17 +181,18 @@ FAST002.py:35:5: FAST002 [*] FastAPI dependency without `Annotated`
 37 38 |     some_file_param: UploadFile = File(),
 38 39 |     some_form_param: str = Form(),

-FAST002.py:36:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 36:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:36:5
   |
 34 |     some_body_param: str = Body("foo"),
 35 |     some_cookie_param: str = Cookie(),
 36 |     some_header_param: int = Header(default=5),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 37 |     some_file_param: UploadFile = File(),
 38 |     some_form_param: str = Form(),
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -204,17 +211,18 @@ FAST002.py:36:5: FAST002 [*] FastAPI dependency without `Annotated`
 38 39 |     some_form_param: str = Form(),
 39 40 | ):

-FAST002.py:37:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 37:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:37:5
   |
 35 |     some_cookie_param: str = Cookie(),
 36 |     some_header_param: int = Header(default=5),
 37 |     some_file_param: UploadFile = File(),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 38 |     some_form_param: str = Form(),
 39 | ):
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
@@ -233,17 +241,18 @@ FAST002.py:37:5: FAST002 [*] FastAPI dependency without `Annotated`
 39 40 | ):
 40 41 |     # do stuff

-FAST002.py:38:5: FAST002 [*] FastAPI dependency without `Annotated`
+error[FAST002]: 38:5: [*] FastAPI dependency without `Annotated`
+
+  --> FAST002.py:38:5
   |
 36 |     some_header_param: int = Header(default=5),
 37 |     some_file_param: UploadFile = File(),
 38 |     some_form_param: str = Form(),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST002
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 39 | ):
 40 |     # do stuff
   |
   = help: Replace with `Annotated`
-
 ℹ Unsafe fix
 12 12 |     Security,
 13 13 | )
--- a/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-redundant-response-model_FAST001.py.snap
+++ b/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-redundant-response-model_FAST001.py.snap
@@ -1,15 +1,16 @@
 ---
 source: crates/ruff_linter/src/rules/fastapi/mod.rs
 ---
-FAST001.py:17:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 17:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:17:22
   |
 17 | @app.post("/items/", response_model=Item)
-   |                      ^^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^^
 18 | async def create_item(item: Item) -> Item:
 19 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 14 14 | # Errors
 15 15 | 
@@ -20,15 +21,16 @@ FAST001.py:17:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 19 19 |     return item
 20 20 | 

-FAST001.py:22:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 22:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:22:22
   |
 22 | @app.post("/items/", response_model=list[Item])
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^
 23 | async def create_item(item: Item) -> list[Item]:
 24 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 19 19 |     return item
 20 20 | 
@@ -39,15 +41,16 @@ FAST001.py:22:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 24 24 |     return item
 25 25 | 

-FAST001.py:27:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 27:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:27:22
   |
 27 | @app.post("/items/", response_model=List[Item])
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^
 28 | async def create_item(item: Item) -> List[Item]:
 29 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 24 24 |     return item
 25 25 | 
@@ -58,15 +61,16 @@ FAST001.py:27:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 29 29 |     return item
 30 30 | 

-FAST001.py:32:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 32:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:32:22
   |
 32 | @app.post("/items/", response_model=Dict[str, Item])
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 33 | async def create_item(item: Item) -> Dict[str, Item]:
 34 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 29 29 |     return item
 30 30 | 
@@ -77,15 +81,16 @@ FAST001.py:32:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 34 34 |     return item
 35 35 | 

-FAST001.py:37:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 37:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:37:22
   |
 37 | @app.post("/items/", response_model=str)
-   |                      ^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^
 38 | async def create_item(item: Item) -> str:
 39 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 34 34 |     return item
 35 35 | 
@@ -96,15 +101,16 @@ FAST001.py:37:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 39 39 |     return item
 40 40 | 

-FAST001.py:42:21: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 42:21: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:42:21
   |
 42 | @app.get("/items/", response_model=Item)
-   |                     ^^^^^^^^^^^^^^^^^^^ FAST001
+   |                     ^^^^^^^^^^^^^^^^^^^
 43 | async def create_item(item: Item) -> Item:
 44 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 39 39 |     return item
 40 40 | 
@@ -115,15 +121,16 @@ FAST001.py:42:21: FAST001 [*] FastAPI route with redundant `response_model` argu
 44 44 |     return item
 45 45 | 

-FAST001.py:47:21: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 47:21: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:47:21
   |
 47 | @app.get("/items/", response_model=Item)
-   |                     ^^^^^^^^^^^^^^^^^^^ FAST001
+   |                     ^^^^^^^^^^^^^^^^^^^
 48 | @app.post("/items/", response_model=Item)
 49 | async def create_item(item: Item) -> Item:
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 44 44 |     return item
 45 45 | 
@@ -134,16 +141,17 @@ FAST001.py:47:21: FAST001 [*] FastAPI route with redundant `response_model` argu
 49 49 | async def create_item(item: Item) -> Item:
 50 50 |     return item

-FAST001.py:48:22: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 48:22: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:48:22
   |
 47 | @app.get("/items/", response_model=Item)
 48 | @app.post("/items/", response_model=Item)
-   |                      ^^^^^^^^^^^^^^^^^^^ FAST001
+   |                      ^^^^^^^^^^^^^^^^^^^
 49 | async def create_item(item: Item) -> Item:
 50 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 45 45 | 
 46 46 | 
@@ -154,15 +162,16 @@ FAST001.py:48:22: FAST001 [*] FastAPI route with redundant `response_model` argu
 50 50 |     return item
 51 51 | 

-FAST001.py:53:24: FAST001 [*] FastAPI route with redundant `response_model` argument
+error[FAST001]: 53:24: [*] FastAPI route with redundant `response_model` argument
+
+  --> FAST001.py:53:24
   |
 53 | @router.get("/items/", response_model=Item)
-   |                        ^^^^^^^^^^^^^^^^^^^ FAST001
+   |                        ^^^^^^^^^^^^^^^^^^^
 54 | async def create_item(item: Item) -> Item:
 55 |     return item
   |
   = help: Remove argument
-
 ℹ Unsafe fix
 50 50 |     return item
 51 51 | 
--- a/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-unused-path-parameter_FAST003.py.snap
+++ b/crates/ruff_linter/src/rules/fastapi/snapshots/ruff_linterrulesfastapitestsfast-api-unused-path-parameter_FAST003.py.snap
@@ -1,16 +1,17 @@
 ---
 source: crates/ruff_linter/src/rules/fastapi/mod.rs
 ---
-FAST003.py:7:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 7:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+ --> FAST003.py:7:19
  |
 6 | # Errors
 7 | @app.get("/things/{thing_id}")
-  |                   ^^^^^^^^^^ FAST003
+  |                   ^^^^^^^^^^
 8 | async def read_thing(query: str):
 9 |     return {"query": query}
  |
  = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 5 5 | 
 6 6 | # Errors
@@ -21,15 +22,16 @@ FAST003.py:7:19: FAST003 [*] Parameter `thing_id` appears in route path, but not
 10 10 | 
 11 11 | 

-FAST003.py:12:23: FAST003 [*] Parameter `isbn` appears in route path, but not in `read_thing` signature
+error[FAST003]: 12:23: [*] Parameter `isbn` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:12:23
   |
 12 | @app.get("/books/isbn-{isbn}")
-   |                       ^^^^^^ FAST003
+   |                       ^^^^^^
 13 | async def read_thing():
 14 |     ...
   |
   = help: Add `isbn` to function signature
-
 ℹ Unsafe fix
 10 10 | 
 11 11 | 
@@ -40,15 +42,16 @@ FAST003.py:12:23: FAST003 [*] Parameter `isbn` appears in route path, but not in
 15 15 | 
 16 16 | 

-FAST003.py:17:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 17:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:17:19
   |
 17 | @app.get("/things/{thing_id:path}")
-   |                   ^^^^^^^^^^^^^^^ FAST003
+   |                   ^^^^^^^^^^^^^^^
 18 | async def read_thing(query: str):
 19 |     return {"query": query}
   |
   = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 15 15 | 
 16 16 | 
@@ -59,15 +62,16 @@ FAST003.py:17:19: FAST003 [*] Parameter `thing_id` appears in route path, but no
 20 20 | 
 21 21 | 

-FAST003.py:22:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 22:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:22:19
   |
 22 | @app.get("/things/{thing_id : path}")
-   |                   ^^^^^^^^^^^^^^^^^ FAST003
+   |                   ^^^^^^^^^^^^^^^^^
 23 | async def read_thing(query: str):
 24 |     return {"query": query}
   |
   = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 20 20 | 
 21 21 | 
@@ -78,15 +82,16 @@ FAST003.py:22:19: FAST003 [*] Parameter `thing_id` appears in route path, but no
 25 25 | 
 26 26 | 

-FAST003.py:27:27: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+error[FAST003]: 27:27: [*] Parameter `title` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:27:27
   |
 27 | @app.get("/books/{author}/{title}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 28 | async def read_thing(author: str):
 29 |     return {"author": author}
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 25 25 | 
 26 26 | 
@@ -97,15 +102,16 @@ FAST003.py:27:27: FAST003 [*] Parameter `title` appears in route path, but not i
 30 30 | 
 31 31 | 

-FAST003.py:32:18: FAST003 [*] Parameter `author_name` appears in route path, but not in `read_thing` signature
+error[FAST003]: 32:18: [*] Parameter `author_name` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:32:18
   |
 32 | @app.get("/books/{author_name}/{title}")
-   |                  ^^^^^^^^^^^^^ FAST003
+   |                  ^^^^^^^^^^^^^
 33 | async def read_thing():
 34 |     ...
   |
   = help: Add `author_name` to function signature
-
 ℹ Unsafe fix
 30 30 | 
 31 31 | 
@@ -116,15 +122,16 @@ FAST003.py:32:18: FAST003 [*] Parameter `author_name` appears in route path, but
 35 35 | 
 36 36 | 

-FAST003.py:32:32: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+error[FAST003]: 32:32: [*] Parameter `title` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:32:32
   |
 32 | @app.get("/books/{author_name}/{title}")
-   |                                ^^^^^^^ FAST003
+   |                                ^^^^^^^
 33 | async def read_thing():
 34 |     ...
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 30 30 | 
 31 31 | 
@@ -135,31 +142,34 @@ FAST003.py:32:32: FAST003 [*] Parameter `title` appears in route path, but not i
 35 35 | 
 36 36 | 

-FAST003.py:37:18: FAST003 Parameter `author` appears in route path, but only as a positional-only argument in `read_thing` signature
+error[FAST003]: 37:18: Parameter `author` appears in route path, but only as a positional-only argument in `read_thing` signature
+
+  --> FAST003.py:37:18
   |
 37 | @app.get("/books/{author}/{title}")
-   |                  ^^^^^^^^ FAST003
+   |                  ^^^^^^^^
 38 | async def read_thing(author: str, title: str, /):
 39 |     return {"author": author, "title": title}
   |
+error[FAST003]: 37:27: Parameter `title` appears in route path, but only as a positional-only argument in `read_thing` signature

-FAST003.py:37:27: FAST003 Parameter `title` appears in route path, but only as a positional-only argument in `read_thing` signature
+  --> FAST003.py:37:27
   |
 37 | @app.get("/books/{author}/{title}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 38 | async def read_thing(author: str, title: str, /):
 39 |     return {"author": author, "title": title}
   |
+error[FAST003]: 42:27: [*] Parameter `title` appears in route path, but not in `read_thing` signature

-FAST003.py:42:27: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+  --> FAST003.py:42:27
   |
 42 | @app.get("/books/{author}/{title}/{page}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 43 | async def read_thing(
 44 |     author: str,
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 42 42 | @app.get("/books/{author}/{title}/{page}")
 43 43 | async def read_thing(
@@ -170,15 +180,16 @@ FAST003.py:42:27: FAST003 [*] Parameter `title` appears in route path, but not i
 47 47 | 
 48 48 | 

-FAST003.py:42:35: FAST003 [*] Parameter `page` appears in route path, but not in `read_thing` signature
+error[FAST003]: 42:35: [*] Parameter `page` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:42:35
   |
 42 | @app.get("/books/{author}/{title}/{page}")
-   |                                   ^^^^^^ FAST003
+   |                                   ^^^^^^
 43 | async def read_thing(
 44 |     author: str,
   |
   = help: Add `page` to function signature
-
 ℹ Unsafe fix
 42 42 | @app.get("/books/{author}/{title}/{page}")
 43 43 | async def read_thing(
@@ -189,15 +200,16 @@ FAST003.py:42:35: FAST003 [*] Parameter `page` appears in route path, but not in
 47 47 | 
 48 48 | 

-FAST003.py:49:18: FAST003 [*] Parameter `author` appears in route path, but not in `read_thing` signature
+error[FAST003]: 49:18: [*] Parameter `author` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:49:18
   |
 49 | @app.get("/books/{author}/{title}")
-   |                  ^^^^^^^^ FAST003
+   |                  ^^^^^^^^
 50 | async def read_thing():
 51 |     ...
   |
   = help: Add `author` to function signature
-
 ℹ Unsafe fix
 47 47 | 
 48 48 | 
@@ -208,15 +220,16 @@ FAST003.py:49:18: FAST003 [*] Parameter `author` appears in route path, but not
 52 52 | 
 53 53 | 

-FAST003.py:49:27: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+error[FAST003]: 49:27: [*] Parameter `title` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:49:27
   |
 49 | @app.get("/books/{author}/{title}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 50 | async def read_thing():
 51 |     ...
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 47 47 | 
 48 48 | 
@@ -227,15 +240,16 @@ FAST003.py:49:27: FAST003 [*] Parameter `title` appears in route path, but not i
 52 52 | 
 53 53 | 

-FAST003.py:54:27: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+error[FAST003]: 54:27: [*] Parameter `title` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:54:27
   |
 54 | @app.get("/books/{author}/{title}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 55 | async def read_thing(*, author: str):
 56 |     ...
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 52 52 | 
 53 53 | 
@@ -246,15 +260,16 @@ FAST003.py:54:27: FAST003 [*] Parameter `title` appears in route path, but not i
 57 57 | 
 58 58 | 

-FAST003.py:59:27: FAST003 [*] Parameter `title` appears in route path, but not in `read_thing` signature
+error[FAST003]: 59:27: [*] Parameter `title` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:59:27
   |
 59 | @app.get("/books/{author}/{title}")
-   |                           ^^^^^^^ FAST003
+   |                           ^^^^^^^
 60 | async def read_thing(hello, /, *, author: str):
 61 |     ...
   |
   = help: Add `title` to function signature
-
 ℹ Unsafe fix
 57 57 | 
 58 58 | 
@@ -265,15 +280,16 @@ FAST003.py:59:27: FAST003 [*] Parameter `title` appears in route path, but not i
 62 62 | 
 63 63 | 

-FAST003.py:64:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 64:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:64:19
   |
 64 | @app.get("/things/{thing_id}")
-   |                   ^^^^^^^^^^ FAST003
+   |                   ^^^^^^^^^^
 65 | async def read_thing(
 66 |         query: str,
   |
   = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 63 63 | 
 64 64 | @app.get("/things/{thing_id}")
@@ -284,15 +300,16 @@ FAST003.py:64:19: FAST003 [*] Parameter `thing_id` appears in route path, but no
 68 68 |     return {"query": query}
 69 69 | 

-FAST003.py:71:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 71:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:71:19
   |
 71 | @app.get("/things/{thing_id}")
-   |                   ^^^^^^^^^^ FAST003
+   |                   ^^^^^^^^^^
 72 | async def read_thing(
 73 |         query: str = "default",
   |
   = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 70 70 | 
 71 71 | @app.get("/things/{thing_id}")
@@ -303,15 +320,16 @@ FAST003.py:71:19: FAST003 [*] Parameter `thing_id` appears in route path, but no
 75 75 |     return {"query": query}
 76 76 | 

-FAST003.py:78:19: FAST003 [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+error[FAST003]: 78:19: [*] Parameter `thing_id` appears in route path, but not in `read_thing` signature
+
+  --> FAST003.py:78:19
   |
 78 | @app.get("/things/{thing_id}")
-   |                   ^^^^^^^^^^ FAST003
+   |                   ^^^^^^^^^^
 79 | async def read_thing(
 80 |         *, query: str = "default",
   |
   = help: Add `thing_id` to function signature
-
 ℹ Unsafe fix
 77 77 | 
 78 78 | @app.get("/things/{thing_id}")
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT101_YTT101.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT101_YTT101.py.snap
@@ -1,32 +1,34 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT101.py:6:7: YTT101 `sys.version[:3]` referenced (python3.10), use `sys.version_info`
+error[YTT101]: 6:7: `sys.version[:3]` referenced (python3.10), use `sys.version_info`
+
+ --> YTT101.py:6:7
  |
 4 | print(sys.version)
 5 | 
 6 | print(sys.version[:3])
-  |       ^^^^^^^^^^^ YTT101
+  |       ^^^^^^^^^^^
 7 | print(version[:3])
 8 | print(v[:3])
  |
+error[YTT101]: 7:7: `sys.version[:3]` referenced (python3.10), use `sys.version_info`

-YTT101.py:7:7: YTT101 `sys.version[:3]` referenced (python3.10), use `sys.version_info`
+ --> YTT101.py:7:7
  |
 6 | print(sys.version[:3])
 7 | print(version[:3])
-  |       ^^^^^^^ YTT101
+  |       ^^^^^^^
 8 | print(v[:3])
  |
+error[YTT101]: 8:7: `sys.version[:3]` referenced (python3.10), use `sys.version_info`

-YTT101.py:8:7: YTT101 `sys.version[:3]` referenced (python3.10), use `sys.version_info`
+  --> YTT101.py:8:7
   |
 6 | print(sys.version[:3])
 7 | print(version[:3])
 8 | print(v[:3])
-   |       ^ YTT101
+   |       ^
 9 | 
 10 | # the tool is timid and only flags certain numeric slices
   |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT102_YTT102.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT102_YTT102.py.snap
@@ -1,20 +1,21 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT102.py:4:12: YTT102 `sys.version[2]` referenced (python3.10), use `sys.version_info`
+error[YTT102]: 4:12: `sys.version[2]` referenced (python3.10), use `sys.version_info`
+
+ --> YTT102.py:4:12
  |
 2 | from sys import version
 3 | 
 4 | py_minor = sys.version[2]
-  |            ^^^^^^^^^^^ YTT102
+  |            ^^^^^^^^^^^
 5 | py_minor = version[2]
  |
+error[YTT102]: 5:12: `sys.version[2]` referenced (python3.10), use `sys.version_info`

-YTT102.py:5:12: YTT102 `sys.version[2]` referenced (python3.10), use `sys.version_info`
+ --> YTT102.py:5:12
  |
 4 | py_minor = sys.version[2]
 5 | py_minor = version[2]
-  |            ^^^^^^^ YTT102
+  |            ^^^^^^^
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT103_YTT103.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT103_YTT103.py.snap
@@ -1,50 +1,54 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT103.py:4:1: YTT103 `sys.version` compared to string (python3.10), use `sys.version_info`
+error[YTT103]: 4:1: `sys.version` compared to string (python3.10), use `sys.version_info`
+
+ --> YTT103.py:3:1
  |
 2 | from sys import version
 3 | 
 4 | version < "3.5"
-  | ^^^^^^^ YTT103
+  | ^^^^^^^
 5 | sys.version < "3.5"
 6 | sys.version <= "3.5"
  |
+error[YTT103]: 5:1: `sys.version` compared to string (python3.10), use `sys.version_info`

-YTT103.py:5:1: YTT103 `sys.version` compared to string (python3.10), use `sys.version_info`
+ --> YTT103.py:4:16
  |
 4 | version < "3.5"
 5 | sys.version < "3.5"
-  | ^^^^^^^^^^^ YTT103
+  | ^^^^^^^^^^^
 6 | sys.version <= "3.5"
 7 | sys.version > "3.5"
  |
+error[YTT103]: 6:1: `sys.version` compared to string (python3.10), use `sys.version_info`

-YTT103.py:6:1: YTT103 `sys.version` compared to string (python3.10), use `sys.version_info`
+ --> YTT103.py:5:20
  |
 4 | version < "3.5"
 5 | sys.version < "3.5"
 6 | sys.version <= "3.5"
-  | ^^^^^^^^^^^ YTT103
+  | ^^^^^^^^^^^
 7 | sys.version > "3.5"
 8 | sys.version >= "3.5"
  |
+error[YTT103]: 7:1: `sys.version` compared to string (python3.10), use `sys.version_info`

-YTT103.py:7:1: YTT103 `sys.version` compared to string (python3.10), use `sys.version_info`
+ --> YTT103.py:6:21
  |
 5 | sys.version < "3.5"
 6 | sys.version <= "3.5"
 7 | sys.version > "3.5"
-  | ^^^^^^^^^^^ YTT103
+  | ^^^^^^^^^^^
 8 | sys.version >= "3.5"
  |
+error[YTT103]: 8:1: `sys.version` compared to string (python3.10), use `sys.version_info`

-YTT103.py:8:1: YTT103 `sys.version` compared to string (python3.10), use `sys.version_info`
+ --> YTT103.py:7:20
  |
 6 | sys.version <= "3.5"
 7 | sys.version > "3.5"
 8 | sys.version >= "3.5"
-  | ^^^^^^^^^^^ YTT103
+  | ^^^^^^^^^^^
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT201_YTT201.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT201_YTT201.py.snap
@@ -1,40 +1,43 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT201.py:7:7: YTT201 `sys.version_info[0] == 3` referenced (python4), use `>=`
+error[YTT201]: 7:7: `sys.version_info[0] == 3` referenced (python4), use `>=`
+
+ --> YTT201.py:7:7
  |
 5 | PY3 = sys.version_info[0] >= 3
 6 | 
 7 | PY3 = sys.version_info[0] == 3
-  |       ^^^^^^^^^^^^^^^^^^^ YTT201
+  |       ^^^^^^^^^^^^^^^^^^^
 8 | PY3 = version_info[0] == 3
 9 | PY2 = sys.version_info[0] != 3
  |
+error[YTT201]: 8:7: `sys.version_info[0] == 3` referenced (python4), use `>=`

-YTT201.py:8:7: YTT201 `sys.version_info[0] == 3` referenced (python4), use `>=`
+  --> YTT201.py:8:7
   |
 7 | PY3 = sys.version_info[0] == 3
 8 | PY3 = version_info[0] == 3
-   |       ^^^^^^^^^^^^^^^ YTT201
+   |       ^^^^^^^^^^^^^^^
 9 | PY2 = sys.version_info[0] != 3
 10 | PY2 = version_info[0] != 3
   |
+error[YTT201]: 9:7: `sys.version_info[0] == 3` referenced (python4), use `>=`

-YTT201.py:9:7: YTT201 `sys.version_info[0] == 3` referenced (python4), use `>=`
+  --> YTT201.py:9:7
   |
 7 | PY3 = sys.version_info[0] == 3
 8 | PY3 = version_info[0] == 3
 9 | PY2 = sys.version_info[0] != 3
-   |       ^^^^^^^^^^^^^^^^^^^ YTT201
+   |       ^^^^^^^^^^^^^^^^^^^
 10 | PY2 = version_info[0] != 3
   |
+error[YTT201]: 10:7: `sys.version_info[0] == 3` referenced (python4), use `>=`

-YTT201.py:10:7: YTT201 `sys.version_info[0] == 3` referenced (python4), use `>=`
+  --> YTT201.py:10:7
   |
 8 | PY3 = version_info[0] == 3
 9 | PY2 = sys.version_info[0] != 3
 10 | PY2 = version_info[0] != 3
-   |       ^^^^^^^^^^^^^^^ YTT201
+   |       ^^^^^^^^^^^^^^^
   |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT202_YTT202.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT202_YTT202.py.snap
@@ -1,23 +1,24 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT202.py:4:4: YTT202 `six.PY3` referenced (python4), use `not six.PY2`
+error[YTT202]: 4:4: `six.PY3` referenced (python4), use `not six.PY2`
+
+ --> YTT202.py:4:4
  |
 2 | from six import PY3
 3 | 
 4 | if six.PY3:
-  |    ^^^^^^^ YTT202
+  |    ^^^^^^^
 5 |     print("3")
 6 | if PY3:
  |
+error[YTT202]: 6:4: `six.PY3` referenced (python4), use `not six.PY2`

-YTT202.py:6:4: YTT202 `six.PY3` referenced (python4), use `not six.PY2`
+ --> YTT202.py:6:4
  |
 4 | if six.PY3:
 5 |     print("3")
 6 | if PY3:
-  |    ^^^ YTT202
+  |    ^^^
 7 |     print("3")
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT203_YTT203.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT203_YTT203.py.snap
@@ -1,20 +1,21 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT203.py:4:1: YTT203 `sys.version_info[1]` compared to integer (python4), compare `sys.version_info` to tuple
+error[YTT203]: 4:1: `sys.version_info[1]` compared to integer (python4), compare `sys.version_info` to tuple
+
+ --> YTT203.py:3:1
  |
 2 | from sys import version_info
 3 | 
 4 | sys.version_info[1] >= 5
-  | ^^^^^^^^^^^^^^^^^^^ YTT203
+  | ^^^^^^^^^^^^^^^^^^^
 5 | version_info[1] < 6
  |
+error[YTT203]: 5:1: `sys.version_info[1]` compared to integer (python4), compare `sys.version_info` to tuple

-YTT203.py:5:1: YTT203 `sys.version_info[1]` compared to integer (python4), compare `sys.version_info` to tuple
+ --> YTT203.py:4:25
  |
 4 | sys.version_info[1] >= 5
 5 | version_info[1] < 6
-  | ^^^^^^^^^^^^^^^ YTT203
+  | ^^^^^^^^^^^^^^^
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT204_YTT204.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT204_YTT204.py.snap
@@ -1,20 +1,21 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT204.py:4:1: YTT204 `sys.version_info.minor` compared to integer (python4), compare `sys.version_info` to tuple
+error[YTT204]: 4:1: `sys.version_info.minor` compared to integer (python4), compare `sys.version_info` to tuple
+
+ --> YTT204.py:3:1
  |
 2 | from sys import version_info
 3 | 
 4 | sys.version_info.minor <= 7
-  | ^^^^^^^^^^^^^^^^^^^^^^ YTT204
+  | ^^^^^^^^^^^^^^^^^^^^^^
 5 | version_info.minor > 8
  |
+error[YTT204]: 5:1: `sys.version_info.minor` compared to integer (python4), compare `sys.version_info` to tuple

-YTT204.py:5:1: YTT204 `sys.version_info.minor` compared to integer (python4), compare `sys.version_info` to tuple
+ --> YTT204.py:4:28
  |
 4 | sys.version_info.minor <= 7
 5 | version_info.minor > 8
-  | ^^^^^^^^^^^^^^^^^^ YTT204
+  | ^^^^^^^^^^^^^^^^^^
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT301_YTT301.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT301_YTT301.py.snap
@@ -1,20 +1,21 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT301.py:4:12: YTT301 `sys.version[0]` referenced (python10), use `sys.version_info`
+error[YTT301]: 4:12: `sys.version[0]` referenced (python10), use `sys.version_info`
+
+ --> YTT301.py:4:12
  |
 2 | from sys import version
 3 | 
 4 | py_major = sys.version[0]
-  |            ^^^^^^^^^^^ YTT301
+  |            ^^^^^^^^^^^
 5 | py_major = version[0]
  |
+error[YTT301]: 5:12: `sys.version[0]` referenced (python10), use `sys.version_info`

-YTT301.py:5:12: YTT301 `sys.version[0]` referenced (python10), use `sys.version_info`
+ --> YTT301.py:5:12
  |
 4 | py_major = sys.version[0]
 5 | py_major = version[0]
-  |            ^^^^^^^ YTT301
+  |            ^^^^^^^
  |
-
-
--- a/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT302_YTT302.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_2020/snapshots/ruff_linterrulesflake8_2020testsYTT302_YTT302.py.snap
@@ -1,50 +1,54 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_2020/mod.rs
 ---
-YTT302.py:4:1: YTT302 `sys.version` compared to string (python10), use `sys.version_info`
+error[YTT302]: 4:1: `sys.version` compared to string (python10), use `sys.version_info`
+
+ --> YTT302.py:3:1
  |
 2 | from sys import version
 3 | 
 4 | version < "3"
-  | ^^^^^^^ YTT302
+  | ^^^^^^^
 5 | sys.version < "3"
 6 | sys.version <= "3"
  |
+error[YTT302]: 5:1: `sys.version` compared to string (python10), use `sys.version_info`

-YTT302.py:5:1: YTT302 `sys.version` compared to string (python10), use `sys.version_info`
+ --> YTT302.py:4:14
  |
 4 | version < "3"
 5 | sys.version < "3"
-  | ^^^^^^^^^^^ YTT302
+  | ^^^^^^^^^^^
 6 | sys.version <= "3"
 7 | sys.version > "3"
  |
+error[YTT302]: 6:1: `sys.version` compared to string (python10), use `sys.version_info`

-YTT302.py:6:1: YTT302 `sys.version` compared to string (python10), use `sys.version_info`
+ --> YTT302.py:5:18
  |
 4 | version < "3"
 5 | sys.version < "3"
 6 | sys.version <= "3"
-  | ^^^^^^^^^^^ YTT302
+  | ^^^^^^^^^^^
 7 | sys.version > "3"
 8 | sys.version >= "3"
  |
+error[YTT302]: 7:1: `sys.version` compared to string (python10), use `sys.version_info`

-YTT302.py:7:1: YTT302 `sys.version` compared to string (python10), use `sys.version_info`
+ --> YTT302.py:6:19
  |
 5 | sys.version < "3"
 6 | sys.version <= "3"
 7 | sys.version > "3"
-  | ^^^^^^^^^^^ YTT302
+  | ^^^^^^^^^^^
 8 | sys.version >= "3"
  |
+error[YTT302]: 8:1: `sys.version` compared to string (python10), use `sys.version_info`

-YTT302.py:8:1: YTT302 `sys.version` compared to string (python10), use `sys.version_info`
+ --> YTT302.py:7:18
  |
 6 | sys.version <= "3"
 7 | sys.version > "3"
 8 | sys.version >= "3"
-  | ^^^^^^^^^^^ YTT302
+  | ^^^^^^^^^^^
  |
-
-
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Micha Reiser	c923ffe389	Update more snapshots	2024-08-23 11:43:37 +02:00
Micha Reiser	aa7393344d	Upgrade annotation snippet	2024-08-23 11:28:59 +02:00
Micha Reiser	4f6accb5c6	Add basic red knot benchmark (#13026 ) Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>	2024-08-23 08:22:42 +02:00
Micha Reiser	1ca14e4335	Move collection of parse errors to `check_file` (#13059 )	2024-08-23 08:22:12 +02:00
Teodoro Freund	b9c8113a8a	Added bytes type and some inference (#13061 ) ## Summary This PR adds the `bytes` type to red-knot: - Added the `bytes` type - Added support for bytes literals - Support for the `+` operator Improves on #12701 Big TODO on supporting and normalizing r-prefixed bytestrings (`rb"hello\n"`) ## Test Plan Added a test for a bytes literals, concatenation, and corner values	2024-08-22 13:27:15 -07:00
Dylan	2edd32aa31	[red-knot] `SemanticIndexBuilder` visits value before target in named expressions (#13053 ) The `SemanticIndexBuilder` was causing a cycle in a salsa query by attempting to resolve the target before the value in a named expression (e.g. `x := x+1`). This PR swaps the order, avoiding a panic. Closes #13012.	2024-08-22 07:59:13 -07:00
Dhruv Manilawala	02c4373a49	Bump version to 0.6.2 (#13056 )	2024-08-22 18:59:27 +05:30
Steve C	d37e2e5d33	[`flake8-simplify`] Extend open-file-with-context-handler to work with other standard-library IO modules (`SIM115`) (#12959 ) Co-authored-by: Alex Waygood <alex.waygood@gmail.com>	2024-08-22 14:18:55 +01:00
Dhruv Manilawala	d1d067896c	[red-knot] Remove notebook support from the server (#13040 ) ## Summary This PR removes notebook sync support from server capabilities because it isn't tested, it'll be added back once we actually add full support for notebook.	2024-08-22 14:55:46 +05:30
olp-cs	93f9023ea3	Add `hyperfine` installation instructions; update `hyperfine` code samples (#13034 ) ## Summary When following the step-by-step instructions to run the benchmarks in `CONTRIBUTING.md`, I encountered two errors: Error 1: `bash: hyperfine: command not found` Solution: I updated the instructions to include the step of installing the benchmark tool. Error 2: ```shell $ ./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ error: `ruff <path>` has been removed. Use `ruff check <path>` instead. ``` Solution: I added `check`. ## Test Plan I tested it by running the benchmark-related commands in a new workspace within GitHub Codespaces.	2024-08-22 09:05:09 +05:30
Dhruv Manilawala	8144a11f98	[red-knot] Add definition for with items (#12920 ) ## Summary This PR adds symbols and definitions introduced by `with` statements. The symbols and definitions are introduced for each with item. The type inference is updated to call the definition region type inference instead. ## Test Plan Add test case to check for symbol table and definitions.	2024-08-22 08:00:19 +05:30
Micha Reiser	dce87c21fd	Eagerly validate typeshed versions (#12786 )	2024-08-21 15:49:53 +00:00
Micha Reiser	f873d2ac12	Revert "Use the system allocator for codspeed benchmarks" (#13035 )	2024-08-21 17:13:11 +02:00
Alex Waygood	ecd9e6a650	[red-knot] Improve the `unresolved-import` check (#13007 ) Co-authored-by: Micha Reiser <micha@reiser.io>	2024-08-21 13:44:49 +00:00
Micha Reiser	785c39927b	Use ZIP file size metadata to allocate string (#13032 )	2024-08-21 12:48:44 +00:00
Micha Reiser	a35cdbb275	Fix various panicks when linting black/src (#13033 )	2024-08-21 12:35:29 +00:00
Dhruv Manilawala	0c98b5949c	Show full error context in server messages (#13029 ) ## Summary Reference: https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations Closes: #13022 ## Test Plan ``` 2024-08-21 15:21:24.831 [info] [Trace - 3:21:24 PM] 0.017255167s ERROR ThreadId(04) ruff_server::session::index::ruff_settings: Failed to parse /Users/dhruv/playground/ruff/pyproject.toml: TOML parse error at line 1, column 1 \| 1 \| [tool.ruff.lint] \| ^^^^^^^^^^^^^^^^ Unknown rule selector: `ME102` ``` Or, ``` 2024-08-21 15:23:47.993 [info] [Trace - 3:23:47 PM] 143.179857375s ERROR ThreadId(66) ruff_server::session::index::ruff_settings: Failed to parse /Users/dhruv/playground/ruff/pyproject.toml: TOML parse error at line 2, column 42 \| 2 \| select = ["ALL", "TD006", "TD007", "FIX" \| ^ invalid array expected `]` ```	2024-08-21 15:36:16 +05:30
Micha Reiser	e5f37a8254	Remove linter dependency from red_knot_server (#13028 )	2024-08-21 10:02:42 +00:00
Micha Reiser	5c5dfc11f0	Upgrade to Salsa with tables (#13016 )	2024-08-21 06:58:53 +00:00
Micha Reiser	678045e1aa	Use the system allocator for codspeed benchmarks (#13005 )	2024-08-21 08:46:51 +02:00
François-Michel L'Heureux	dedefd73da	Update example for `PT001` as per the new default behavior (#13019 ) ## Summary Example / Use instead were not updated with the release of ruff 0.6.0. This updates them accordingly.	2024-08-21 09:34:18 +05:30
Alex Waygood	37a60460ed	[red-knot] Improve various tracing logs (#13015 )	2024-08-20 18:34:51 +00:00
Micha Reiser	0bd258a370	Use `check` instead of `check_file` in benchmarks (#13004 )	2024-08-20 12:20:40 +02:00
Dylan	9baab8672a	[`flake8-pyi`] Skip type annotations in `string-or-bytes-too-long` (`PYI053`) (#13002 )	2024-08-20 10:53:22 +01:00
Micha Reiser	c65e3310d5	Add API to emit type-checking diagnostics (#12988 ) Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>	2024-08-20 07:22:30 +00:00
Micha Reiser	38c19fb96e	Fix re-entrance deadlock in Package::files (#12948 )	2024-08-20 06:51:08 +00:00
Alex Lowe	abb4cdbf3d	pydocstyle: Add ignore setting to linter docs (#12996 )	2024-08-20 08:33:50 +02:00
tfardet	fc811f5168	Expand note to use Ruff with other language server in Kate (#12806 ) ## Summary Provide instructions to use Ruff together with other servers in the Kate editor. Because Kate does not support running multiple servers for the same language, one needs to use the ``python-lsp-server`` (pylsp) tool. --------- Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>	2024-08-20 06:18:31 +00:00
Dhruv Manilawala	1a8f29ea41	[red-knot] Add symbols defined by `match` statements (#12926 ) ## Summary This PR adds symbols introduced by `match` statements. There are three patterns that introduces new symbols: * `as` pattern * Sequence pattern * Mapping pattern The recursive nature of the visitor makes sure that all symbols are added. ## Test Plan Add test case for all types of patterns that introduces a symbol.	2024-08-20 05:16:27 +00:00
Dhruv Manilawala	aefaddeae7	[red-knot] Add definition for augmented assignment (#12892 ) ## Summary This PR adds definition for augmented assignment. This is similar to annotated assignment in terms of implementation. An augmented assignment should also record a use of the variable but that's a TODO for now. ## Test Plan Add test case to validate that a definition is added.	2024-08-20 10:33:55 +05:30
Mathieu Kniewallner	df09045176	docs: add stricter validation options (#12998 ) ## Summary Applying the same change as done in https://github.com/astral-sh/uv/pull/6096. Note that in `uv` repository, this [broke the docs build](https://github.com/astral-sh/uv/pull/6096#issuecomment-2290151150) because `anchors` is `mdkocs` 1.6+ only, and insiders used 1.5.0 while public dependencies used 1.6.0, but in this repository, both use 1.6.0 ([public](`049cda2ff3/docs/requirements.txt (L3)`), [insiders](`049cda2ff3/docs/requirements-insiders.txt (L3)`)), so this should not be an issue to have in the template. Contrarily to `uv` repository, no violations were reported here, but this could prevent adding some in the future. ## Test Plan Local run of the documentation + `mkdocs build --strict`.	2024-08-19 18:07:41 -05:00
Alex Waygood	049cda2ff3	`flake8-type-checking`: Always recognise relative imports as first-party (#12994 )	2024-08-19 19:06:56 +01:00
renovate[bot]	358792f2c9	Update pre-commit dependencies (#12978 ) Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com> Co-authored-by: Alex Waygood <alex.waygood@gmail.com>	2024-08-19 13:41:03 +02:00
Alex Waygood	e6d5a7af37	Add the `testing` feature of `ruff_db` as a dev-dependency for `ruff_workspace` (#12985 )	2024-08-19 10:22:01 +00:00
Mathieu Kniewallner	f5bff82e70	docs(contributing): remove TOC (#12903 ) Co-authored-by: Micha Reiser <micha@reiser.io>	2024-08-19 09:38:08 +00:00
Alex Waygood	ab44152eb5	Improve release instructions for when `ruff-lsp` and `ruff-vscode` updates are required (#12952 )	2024-08-19 10:29:16 +01:00
Ken Baskett	f4c8c7eb70	[ruff] Implement check for Decimal called with a float literal (RUF032) (#12909 ) Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com> Co-authored-by: Micha Reiser <micha@reiser.io>	2024-08-19 09:22:19 +00:00
InSync	65de8f2c9b	Quote default values consistently (#12981 ) Co-authored-by: Micha Reiser <micha@reiser.io>	2024-08-19 08:02:55 +00:00
renovate[bot]	e6226436fd	Update NPM Development dependencies (#12976 ) Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com> Co-authored-by: Micha Reiser <micha@reiser.io>	2024-08-19 07:44:21 +00:00
renovate[bot]	0345d46759	Update dependency react-resizable-panels to v2.1.0 (#12977 ) Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>	2024-08-19 09:40:48 +02:00