Use salsa accumulators for diagnostics

## Summary

Just some minor followups to the recently merged RUF052 rule, that was
added in bf0fd04:
- Some small tweaks to the docs
- A minor code-style nit
- Some more tests for my peace of mind, just to check that the new
methods on the semantic model are working correctly

I'm adding the "internal" label as this doesn't deserve a changelog
entry. RUF052 is a new rule that hasn't been released yet.

## Test Plan

`cargo test -p ruff_linter`

.github/CODEOWNERS

@@ -13,9 +13,10 @@
 # flake8-pyi
 /crates/ruff_linter/src/rules/flake8_pyi/ @AlexWaygood
 
-# Script for fuzzing the parser
-/scripts/fuzz-parser/ @AlexWaygood
+# Script for fuzzing the parser/red-knot etc.
+/python/py-fuzzer/ @AlexWaygood
 
 # red-knot
 /crates/red_knot* @carljm @MichaReiser @AlexWaygood @sharkdp
 /crates/ruff_db/ @carljm @MichaReiser @AlexWaygood @sharkdp
+/scripts/knot_benchmark/ @carljm @MichaReiser @AlexWaygood @sharkdp

.github/workflows/ci.yaml

@@ -49,7 +49,7 @@ jobs:
               - crates/ruff_text_size/**
               - crates/ruff_python_ast/**
               - crates/ruff_python_parser/**
-              - scripts/fuzz-parser/**
+              - python/py-fuzzer/**
               - .github/workflows/ci.yaml
 
             linter:
@@ -82,6 +82,7 @@ jobs:
             code:
               - "**/*"
               - "!**/*.md"
+              - "crates/red_knot_python_semantic/resources/mdtest/**/*.md"
               - "!docs/**"
               - "!assets/**"
 
@@ -157,6 +158,33 @@ jobs:
           name: ruff
           path: target/debug/ruff
 
+  cargo-test-linux-release:
+    name: "cargo test (linux, release)"
+    runs-on: depot-ubuntu-22.04-16
+    needs: determine_changes
+    if: ${{ needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main' }}
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+      - name: "Install Rust toolchain"
+        run: rustup show
+      - name: "Install mold"
+        uses: rui314/setup-mold@v1
+      - name: "Install cargo nextest"
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-nextest
+      - name: "Install cargo insta"
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-insta
+      - uses: Swatinem/rust-cache@v2
+      - name: "Run tests"
+        shell: bash
+        env:
+          NEXTEST_PROFILE: "ci"
+        run: cargo insta test --release --all-features --unreferenced reject --test-runner nextest
+
   cargo-test-windows:
     name: "cargo test (windows)"
     runs-on: windows-latest-xlarge
@@ -212,7 +240,6 @@ jobs:
   cargo-build-release:
     name: "cargo build (release)"
     runs-on: macos-latest
-    needs: determine_changes
     if: ${{ github.ref == 'refs/heads/main' }}
     timeout-minutes: 20
     steps:
@@ -291,13 +318,7 @@ jobs:
       FORCE_COLOR: 1
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: Install uv
-        run: curl -LsSf https://astral.sh/uv/install.sh | sh
-      - name: Install Python requirements
-        run: uv pip install -r scripts/fuzz-parser/requirements.txt --system
+      - uses: astral-sh/setup-uv@v4
       - uses: actions/download-artifact@v4
         name: Download Ruff binary to test
         id: download-cached-binary
@@ -309,7 +330,15 @@ jobs:
           # Make executable, since artifact download doesn't preserve this
           chmod +x ${{ steps.download-cached-binary.outputs.download-path }}/ruff
 
-          python scripts/fuzz-parser/fuzz.py 0-500 --test-executable ${{ steps.download-cached-binary.outputs.download-path }}/ruff
+          (
+            uvx \
+            --python=${{ env.PYTHON_VERSION }} \
+            --from=./python/py-fuzzer \
+            fuzz \
+            --test-executable=${{ steps.download-cached-binary.outputs.download-path }}/ruff \
+            --bin=ruff \
+            0-500
+          )
 
   scripts:
     name: "test scripts"
@@ -354,7 +383,7 @@ jobs:
           name: ruff
           path: target/debug
 
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v7
         name: Download baseline Ruff binary
         with:
           name: ruff
@@ -530,7 +559,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: Install uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v4
       - uses: Swatinem/rust-cache@v2
       - name: "Install Insiders dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}

.github/workflows/daily_fuzz.yaml

@@ -32,13 +32,7 @@ jobs:
     if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.12"
-      - name: Install uv
-        run: curl -LsSf https://astral.sh/uv/install.sh | sh
-      - name: Install Python requirements
-        run: uv pip install -r scripts/fuzz-parser/requirements.txt --system
+      - uses: astral-sh/setup-uv@v4
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
@@ -49,7 +43,16 @@ jobs:
         # but this is outweighed by the fact that a release build takes *much* longer to compile in CI
         run: cargo build --locked
       - name: Fuzz
-        run: python scripts/fuzz-parser/fuzz.py $(shuf -i 0-9999999999999999999 -n 1000) --test-executable target/debug/ruff
+        run: |
+          (
+            uvx \
+            --python=3.12 \
+            --from=./python/py-fuzzer \
+            fuzz \
+            --test-executable=target/debug/ruff \
+            --bin=ruff \
+            $(shuf -i 0-9999999999999999999 -n 1000)
+          )
 
   create-issue-on-failure:
     name: Create an issue if the daily fuzz surfaced any bugs

.github/workflows/pr-comment.yaml

@@ -17,7 +17,7 @@ jobs:
   comment:
     runs-on: ubuntu-latest
     steps:
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v7
         name: Download pull request number
         with:
           name: pr-number
@@ -33,7 +33,7 @@ jobs:
             echo "pr-number=$(<pr-number)" >> $GITHUB_OUTPUT
           fi
 
-      - uses: dawidd6/action-download-artifact@v6
+      - uses: dawidd6/action-download-artifact@v7
         name: "Download ecosystem results"
         id: download-ecosystem-result
         if: steps.pr-number.outputs.pr-number

.github/workflows/publish-playground.yml

@@ -47,7 +47,7 @@ jobs:
         working-directory: playground
       - name: "Deploy to Cloudflare Pages"
         if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@v3.12.1
+        uses: cloudflare/wrangler-action@v3.13.0
         with:
           apiToken: ${{ secrets.CF_API_TOKEN }}
           accountId: ${{ secrets.CF_ACCOUNT_ID }}

.github/workflows/publish-pypi.yml

@@ -22,7 +22,7 @@ jobs:
       id-token: write
     steps:
       - name: "Install uv"
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v4
       - uses: actions/download-artifact@v4
         with:
           pattern: wheels-*

.pre-commit-config.yaml

@@ -22,7 +22,7 @@ repos:
       - id: validate-pyproject
 
   - repo: https://github.com/executablebooks/mdformat
-    rev: 0.7.18
+    rev: 0.7.19
     hooks:
       - id: mdformat
         additional_dependencies:
@@ -36,7 +36,7 @@ repos:
           )$
 
   - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.42.0
+    rev: v0.43.0
     hooks:
       - id: markdownlint-fix
         exclude: |
@@ -59,7 +59,7 @@ repos:
           - black==24.10.0
 
   - repo: https://github.com/crate-ci/typos
-    rev: v1.27.3
+    rev: v1.28.1
     hooks:
       - id: typos
 
@@ -73,7 +73,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.7.4
+    rev: v0.8.1
     hooks:
       - id: ruff-format
       - id: ruff
@@ -83,7 +83,7 @@ repos:
 
   # Prettier
   - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.3.3
+    rev: v3.4.1
     hooks:
       - id: prettier
         types: [yaml]

BREAKING_CHANGES.md

@@ -192,7 +192,7 @@ flag or `unsafe-fixes` configuration option can be used to enable unsafe fixes.
 
 See the [docs](https://docs.astral.sh/ruff/configuration/#fix-safety) for details.
 
-### Remove formatter-conflicting rules from the default rule set  ([#7900](https://github.com/astral-sh/ruff/pull/7900))
+### Remove formatter-conflicting rules from the default rule set ([#7900](https://github.com/astral-sh/ruff/pull/7900))
 
 Previously, Ruff enabled all implemented rules in Pycodestyle (`E`) by default. Ruff now only includes the
 Pycodestyle prefixes `E4`, `E7`, and `E9` to exclude rules that conflict with automatic formatters. Consequently,

CHANGELOG.md

@@ -1,5 +1,46 @@
 # Changelog
 
+## 0.8.1
+
+### Preview features
+
+- Formatter: Avoid invalid syntax for format-spec with quotes for all Python versions ([#14625](https://github.com/astral-sh/ruff/pull/14625))
+- Formatter: Consider quotes inside format-specs when choosing the quotes for an f-string ([#14493](https://github.com/astral-sh/ruff/pull/14493))
+- Formatter: Do not consider f-strings with escaped newlines as multiline ([#14624](https://github.com/astral-sh/ruff/pull/14624))
+- Formatter: Fix f-string formatting in assignment statement ([#14454](https://github.com/astral-sh/ruff/pull/14454))
+- Formatter: Fix unnecessary space around power operator (`**`) in overlong f-string expressions ([#14489](https://github.com/astral-sh/ruff/pull/14489))
+- \[`airflow`\] Avoid implicit `schedule` argument to `DAG` and `@dag` (`AIR301`) ([#14581](https://github.com/astral-sh/ruff/pull/14581))
+- \[`flake8-builtins`\] Exempt private built-in modules (`A005`) ([#14505](https://github.com/astral-sh/ruff/pull/14505))
+- \[`flake8-pytest-style`\] Fix `pytest.mark.parametrize` rules to check calls instead of decorators ([#14515](https://github.com/astral-sh/ruff/pull/14515))
+- \[`flake8-type-checking`\] Implement `runtime-cast-value` (`TC006`) ([#14511](https://github.com/astral-sh/ruff/pull/14511))
+- \[`flake8-type-checking`\] Implement `unquoted-type-alias` (`TC007`) and `quoted-type-alias` (`TC008`) ([#12927](https://github.com/astral-sh/ruff/pull/12927))
+- \[`flake8-use-pathlib`\] Recommend `Path.iterdir()` over `os.listdir()` (`PTH208`) ([#14509](https://github.com/astral-sh/ruff/pull/14509))
+- \[`pylint`\] Extend `invalid-envvar-default` to detect `os.environ.get` (`PLW1508`) ([#14512](https://github.com/astral-sh/ruff/pull/14512))
+- \[`pylint`\] Implement `len-test` (`PLC1802`) ([#14309](https://github.com/astral-sh/ruff/pull/14309))
+- \[`refurb`\] Fix bug where methods defined using lambdas were flagged by `FURB118` ([#14639](https://github.com/astral-sh/ruff/pull/14639))
+- \[`ruff`\] Auto-add `r` prefix when string has no backslashes for `unraw-re-pattern` (`RUF039`) ([#14536](https://github.com/astral-sh/ruff/pull/14536))
+- \[`ruff`\] Implement `invalid-assert-message-literal-argument` (`RUF040`) ([#14488](https://github.com/astral-sh/ruff/pull/14488))
+- \[`ruff`\] Implement `unnecessary-nested-literal` (`RUF041`) ([#14323](https://github.com/astral-sh/ruff/pull/14323))
+- \[`ruff`\] Implement `unnecessary-regular-expression` (`RUF055`) ([#14659](https://github.com/astral-sh/ruff/pull/14659))
+
+### Rule changes
+
+- Ignore more rules for stub files ([#14541](https://github.com/astral-sh/ruff/pull/14541))
+- \[`pep8-naming`\] Eliminate false positives for single-letter names (`N811`, `N814`) ([#14584](https://github.com/astral-sh/ruff/pull/14584))
+- \[`pyflakes`\] Avoid false positives in `@no_type_check` contexts (`F821`, `F722`) ([#14615](https://github.com/astral-sh/ruff/pull/14615))
+- \[`ruff`\] Detect redirected-noqa in file-level comments (`RUF101`) ([#14635](https://github.com/astral-sh/ruff/pull/14635))
+- \[`ruff`\] Mark fixes for `unsorted-dunder-all` and `unsorted-dunder-slots` as unsafe when there are complex comments in the sequence (`RUF022`, `RUF023`) ([#14560](https://github.com/astral-sh/ruff/pull/14560))
+
+### Bug fixes
+
+- Avoid fixing code to `None | None` for `redundant-none-literal` (`PYI061`) and `never-union` (`RUF020`) ([#14583](https://github.com/astral-sh/ruff/pull/14583), [#14589](https://github.com/astral-sh/ruff/pull/14589))
+- \[`flake8-bugbear`\] Fix `mutable-contextvar-default` to resolve annotated function calls properly (`B039`) ([#14532](https://github.com/astral-sh/ruff/pull/14532))
+- \[`flake8-pyi`, `ruff`\] Fix traversal of nested literals and unions (`PYI016`, `PYI051`, `PYI055`, `PYI062`, `RUF041`) ([#14641](https://github.com/astral-sh/ruff/pull/14641))
+- \[`flake8-pyi`\] Avoid rewriting invalid type expressions in `unnecessary-type-union` (`PYI055`) ([#14660](https://github.com/astral-sh/ruff/pull/14660))
+- \[`flake8-type-checking`\] Avoid syntax errors and type checking problem for quoted annotations autofix (`TC003`, `TC006`) ([#14634](https://github.com/astral-sh/ruff/pull/14634))
+- \[`pylint`\] Do not wrap function calls in parentheses in the fix for unnecessary-dunder-call (`PLC2801`) ([#14601](https://github.com/astral-sh/ruff/pull/14601))
+- \[`ruff`\] Handle `attrs`'s `auto_attribs` correctly (`RUF009`) ([#14520](https://github.com/astral-sh/ruff/pull/14520))
+
 ## 0.8.0
 
 Check out the [blog post](https://astral.sh/blog/ruff-v0.8.0) for a migration guide and overview of the changes!
@@ -57,7 +98,7 @@ The following rules have been stabilized and are no longer in preview:
 - [`fast-api-redundant-response-model`](https://docs.astral.sh/ruff/rules/fast-api-redundant-response-model/) (`FAST001`)
 - [`fast-api-non-annotated-dependency`](https://docs.astral.sh/ruff/rules/fast-api-non-annotated-dependency/) (`FAST002`)
 - [`dict-index-missing-items`](https://docs.astral.sh/ruff/rules/dict-index-missing-items/) (`PLC0206`)
-- [`pep484-style-positional-only-argument`](https://docs.astral.sh/ruff/rules/pep484-style-positional-only-argument/) (`PYI063`)
+- [`pep484-style-positional-only-parameter`](https://docs.astral.sh/ruff/rules/pep484-style-positional-only-parameter/) (`PYI063`)
 - [`redundant-final-literal`](https://docs.astral.sh/ruff/rules/redundant-final-literal/) (`PYI064`)
 - [`bad-version-info-order`](https://docs.astral.sh/ruff/rules/bad-version-info-order/) (`PYI066`)
 - [`parenthesize-chained-operators`](https://docs.astral.sh/ruff/rules/parenthesize-chained-operators/) (`RUF021`)
@@ -216,7 +257,7 @@ The following fixes have been stabilized:
 ### Preview features
 
 - Fix `E221` and `E222` to flag missing or extra whitespace around `==` operator ([#13890](https://github.com/astral-sh/ruff/pull/13890))
-- Formatter: Alternate quotes for strings inside f-strings in preview  ([#13860](https://github.com/astral-sh/ruff/pull/13860))
+- Formatter: Alternate quotes for strings inside f-strings in preview ([#13860](https://github.com/astral-sh/ruff/pull/13860))
 - Formatter: Join implicit concatenated strings when they fit on a line ([#13663](https://github.com/astral-sh/ruff/pull/13663))
 - \[`pylint`\] Restrict `iteration-over-set` to only work on sets of literals (`PLC0208`) ([#13731](https://github.com/astral-sh/ruff/pull/13731))
 
@@ -1077,7 +1118,7 @@ The following deprecated CLI commands have been removed:
 ### Preview features
 
 - \[`flake8-bugbear`\] Implement `return-in-generator` (`B901`) ([#11644](https://github.com/astral-sh/ruff/pull/11644))
-- \[`flake8-pyi`\] Implement `PYI063` ([#11699](https://github.com/astral-sh/ruff/pull/11699))
+- \[`flake8-pyi`\] Implement `pep484-style-positional-only-parameter` (`PYI063`) ([#11699](https://github.com/astral-sh/ruff/pull/11699))
 - \[`pygrep_hooks`\] Check blanket ignores via file-level pragmas (`PGH004`) ([#11540](https://github.com/astral-sh/ruff/pull/11540))
 
 ### Rule changes
@@ -1231,7 +1272,7 @@ To read more about this exciting milestone, check out our [blog post](https://as
 ### Preview features
 
 - \[`pycodestyle`\] Ignore end-of-line comments when determining blank line rules ([#11342](https://github.com/astral-sh/ruff/pull/11342))
-- \[`pylint`\] Detect `pathlib.Path.open` calls in `unspecified-encoding` (`PLW1514`)  ([#11288](https://github.com/astral-sh/ruff/pull/11288))
+- \[`pylint`\] Detect `pathlib.Path.open` calls in `unspecified-encoding` (`PLW1514`) ([#11288](https://github.com/astral-sh/ruff/pull/11288))
 - \[`flake8-pyi`\] Implement `PYI059` (`generic-not-last-base-class`) ([#11233](https://github.com/astral-sh/ruff/pull/11233))
 - \[`flake8-pyi`\] Implement `PYI062` (`duplicate-literal-member`) ([#11269](https://github.com/astral-sh/ruff/pull/11269))
 
@@ -1606,7 +1647,7 @@ To setup `ruff server` with your editor, refer to the [README.md](https://github
 - \[`pycodestyle`\] Do not ignore lines before the first logical line in blank lines rules. ([#10382](https://github.com/astral-sh/ruff/pull/10382))
 - \[`pycodestyle`\] Do not trigger `E225` and `E275` when the next token is a ')' ([#10315](https://github.com/astral-sh/ruff/pull/10315))
 - \[`pylint`\] Avoid false-positive slot non-assignment for `__dict__` (`PLE0237`) ([#10348](https://github.com/astral-sh/ruff/pull/10348))
-- Gate f-string struct size test for Rustc \< 1.76 ([#10371](https://github.com/astral-sh/ruff/pull/10371))
+- Gate f-string struct size test for Rustc < 1.76 ([#10371](https://github.com/astral-sh/ruff/pull/10371))
 
 ### Documentation
 

CONTRIBUTING.md

@@ -139,7 +139,7 @@ At a high level, the steps involved in adding a new lint rule are as follows:
 1. Create a file for your rule (e.g., `crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_false.rs`).
 
 1. In that file, define a violation struct (e.g., `pub struct AssertFalse`). You can grep for
-    `#[violation]` to see examples.
+    `#[derive(ViolationMetadata)]` to see examples.
 
 1. In that file, define a function that adds the violation to the diagnostic list as appropriate
     (e.g., `pub(crate) fn assert_false`) based on whatever inputs are required for the rule (e.g.,
@@ -863,7 +863,7 @@ each configuration file.
 
 The package root is used to determine a file's "module path". Consider, again, `baz.py`. In that
 case, `./my_project/src/foo` was identified as the package root, so the module path for `baz.py`
-would resolve to  `foo.bar.baz` — as computed by taking the relative path from the package root
+would resolve to `foo.bar.baz` — as computed by taking the relative path from the package root
 (inclusive of the root itself). The module path can be thought of as "the path you would use to
 import the module" (e.g., `import foo.bar.baz`).
 

Cargo.lock

@@ -413,7 +413,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -693,7 +693,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "strsim 0.10.0",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -704,7 +704,7 @@ checksum = "a668eda54683121533a393014d8692171709ff57a7d61f187b6e782719f8933f"
 dependencies = [
  "darling_core",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -758,23 +758,23 @@ dependencies = [
 
 [[package]]
 name = "dir-test"
-version = "0.3.0"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c44bdf9319ad5223afb7eb15a7110452b0adf0373ea6756561b2c708eef0dd1"
+checksum = "b12781621d53fd9087021f5a338df5c57c04f84a6231c1f4726f45e2e333470b"
 dependencies = [
  "dir-test-macros",
 ]
 
 [[package]]
 name = "dir-test-macros"
-version = "0.3.0"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "644f96047137dfaa7a09e34d4623f9e52a1926ecc25ba32ad2ba3fc422536b25"
+checksum = "1340852f50b2285d01a7f598cc5d08b572669c3e09e614925175cc3c26787b91"
 dependencies = [
  "glob",
  "proc-macro2",
  "quote",
- "syn 1.0.109",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -826,7 +826,7 @@ checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -1068,9 +1068,9 @@ dependencies = [
 
 [[package]]
 name = "hashbrown"
-version = "0.15.1"
+version = "0.15.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3a9bfc1af68b1726ea47d3d5109de126281def866b33970e10fbab11b5dafab3"
+checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
 
 [[package]]
 name = "hashlink"
@@ -1246,7 +1246,7 @@ checksum = "1ec89e9337638ecdc08744df490b221a7399bf8d164eb52a665454e60e075ad6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -1314,12 +1314,12 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "2.6.0"
+version = "2.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "707907fe3c25f5424cce2cb7e1cbcafee6bdbe735ca90ef77c29e84591e5b9da"
+checksum = "62f822373a4fe84d4bb149bf54e584a7f4abec90e072ed49cda0edea5b95471f"
 dependencies = [
  "equivalent",
- "hashbrown 0.15.1",
+ "hashbrown 0.15.2",
  "serde",
 ]
 
@@ -1420,7 +1420,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -1485,10 +1485,11 @@ checksum = "8b23360e99b8717f20aaa4598f5a6541efbe30630039fbc7706cf954a87947ae"
 
 [[package]]
 name = "js-sys"
-version = "0.3.72"
+version = "0.3.74"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a88f1bda2bd75b0452a14784937d796722fdebfe50df998aeb3f0b7603019a9"
+checksum = "a865e038f7f6ed956f788f0d7d60c541fff74c7bd74272c5d4cf15c63743e705"
 dependencies = [
+ "once_cell",
  "wasm-bindgen",
 ]
 
@@ -1520,15 +1521,15 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.164"
+version = "0.2.167"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "433bfe06b8c75da9b2e3fbea6e5329ff87748f0b144ef75306e674c3f6f7c13f"
+checksum = "09d6582e104315a817dff97f75133544b2e094ee22447d2acf4a74e189ba06fc"
 
 [[package]]
 name = "libcst"
-version = "1.5.0"
+version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1586dd7a857d8a61a577afde1a24cc9573ff549eff092d5ce968b1ec93cc61b6"
+checksum = "fa3e60579a8cba3d86aa4a5f7fc98973cc0fd2ac270bf02f85a9bef09700b075"
 dependencies = [
  "chic",
  "libcst_derive",
@@ -1546,7 +1547,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2ae40017ac09cd2c6a53504cb3c871c7f2b41466eac5bc66ba63f39073b467b"
 dependencies = [
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -1710,9 +1711,9 @@ checksum = "308d96db8debc727c3fd9744aac51751243420e46edf401010908da7f8d5e57c"
 
 [[package]]
 name = "newtype-uuid"
-version = "1.1.0"
+version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3526cb7c660872e401beaf3297f95f548ce3b4b4bdd8121b7c0713771d7c4a6e"
+checksum = "4c8781e2ef64806278a55ad223f0bc875772fd40e1fe6e73e8adbf027817229d"
 dependencies = [
  "uuid",
 ]
@@ -1833,9 +1834,9 @@ checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
 [[package]]
 name = "ordermap"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31f2bd7b03bf2c767e1bb7b91505dbe022833776e60480275e6f2fb0db0c7503"
+checksum = "f80a48eb68b6a7da9829b8b0429011708f775af80676a91063d023a66a656106"
 dependencies = [
  "indexmap",
 ]
@@ -1910,9 +1911,9 @@ checksum = "1e91099d4268b0e11973f036e885d652fb0b21fedcf69738c627f94db6a44f42"
 
 [[package]]
 name = "pathdiff"
-version = "0.2.2"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d61c5ce1153ab5b689d0c074c4e7fc613e942dfb7dd9eea5ab202d2ad91fe361"
+checksum = "df94ce210e5bc13cb6651479fa48d14f601d9858cfe0467f43ae157023b938d3"
 
 [[package]]
 name = "peg"
@@ -1965,7 +1966,7 @@ dependencies = [
  "once_cell",
  "pep440_rs",
  "regex",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "serde",
  "smallvec",
  "thiserror 1.0.67",
@@ -2012,7 +2013,7 @@ dependencies = [
  "pest_meta",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -2127,9 +2128,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.89"
+version = "1.0.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f139b0662de085916d1fb67d2b4169d1addddda1919e696f3252b740b629986e"
+checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
 dependencies = [
  "unicode-ident",
 ]
@@ -2150,28 +2151,48 @@ dependencies = [
 
 [[package]]
 name = "quick-junit"
-version = "0.5.0"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62ffd2f9a162cfae131bed6d9d1ed60adced33be340a94f96952897d7cb0c240"
+checksum = "3ed1a693391a16317257103ad06a88c6529ac640846021da7c435a06fffdacd7"
 dependencies = [
  "chrono",
  "indexmap",
  "newtype-uuid",
  "quick-xml",
  "strip-ansi-escapes",
- "thiserror 1.0.67",
+ "thiserror 2.0.3",
  "uuid",
 ]
 
 [[package]]
 name = "quick-xml"
-version = "0.36.1"
+version = "0.37.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96a05e2e8efddfa51a84ca47cec303fac86c8541b686d37cac5efc0e094417bc"
+checksum = "f22f29bdff3987b4d8632ef95fd6424ec7e4e0a57e2f4fc63e489e75357f6a03"
 dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "quickcheck"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "588f6378e4dd99458b60ec275b4477add41ce4fa9f64dcba6f15adccb19b50d6"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "quickcheck_macros"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b22a693222d716a9587786f37ac3f6b4faedb5b80c23914e7303ff5a1d8016e9"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.37"
@@ -2266,12 +2287,14 @@ dependencies = [
  "compact_str",
  "countme",
  "dir-test",
- "hashbrown 0.15.1",
+ "hashbrown 0.15.2",
  "indexmap",
  "insta",
  "itertools 0.13.0",
  "memchr",
  "ordermap",
+ "quickcheck",
+ "quickcheck_macros",
  "red_knot_test",
  "red_knot_vendored",
  "ruff_db",
@@ -2282,7 +2305,7 @@ dependencies = [
  "ruff_python_stdlib",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "salsa",
  "serde",
  "smallvec",
@@ -2309,7 +2332,7 @@ dependencies = [
  "ruff_python_ast",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "serde",
  "serde_json",
  "shellexpand",
@@ -2322,6 +2345,7 @@ name = "red_knot_test"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "camino",
  "colored",
  "memchr",
  "red_knot_python_semantic",
@@ -2332,7 +2356,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "salsa",
  "smallvec",
 ]
@@ -2379,8 +2403,7 @@ dependencies = [
  "ruff_cache",
  "ruff_db",
  "ruff_python_ast",
- "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "salsa",
  "serde",
  "thiserror 2.0.3",
@@ -2489,7 +2512,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.8.0"
+version = "0.8.1"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2529,7 +2552,7 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "ruff_workspace",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "serde",
  "serde_json",
  "shellexpand",
@@ -2560,7 +2583,7 @@ dependencies = [
  "ruff_python_formatter",
  "ruff_python_parser",
  "ruff_python_trivia",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "serde",
  "serde_json",
  "tikv-jemallocator",
@@ -2602,11 +2625,10 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "salsa",
  "serde",
  "tempfile",
- "thiserror 2.0.3",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",
@@ -2671,7 +2693,7 @@ dependencies = [
  "ruff_cache",
  "ruff_macros",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
  "static_assertions",
@@ -2708,7 +2730,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.8.0"
+version = "0.8.1"
 dependencies = [
  "aho-corasick",
  "annotate-snippets 0.9.2",
@@ -2749,7 +2771,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
  "serde_json",
@@ -2775,7 +2797,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "ruff_python_trivia",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -2811,7 +2833,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
 ]
@@ -2857,7 +2879,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
  "serde_json",
@@ -2904,7 +2926,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "static_assertions",
  "unicode-ident",
  "unicode-normalization",
@@ -2935,7 +2957,7 @@ dependencies = [
  "ruff_python_parser",
  "ruff_python_stdlib",
  "ruff_text_size",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
 ]
@@ -2993,7 +3015,7 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "ruff_workspace",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "serde",
  "serde_json",
  "shellexpand",
@@ -3023,7 +3045,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.8.0"
+version = "0.8.1"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3074,7 +3096,7 @@ dependencies = [
  "ruff_python_semantic",
  "ruff_python_stdlib",
  "ruff_source_file",
- "rustc-hash 2.0.0",
+ "rustc-hash 2.1.0",
  "schemars",
  "serde",
  "shellexpand",
@@ -3101,9 +3123,9 @@ checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "rustc-hash"
-version = "2.0.0"
+version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "583034fd73374156e66797ed8e5b0d5690409c9226b22d87cb7f19821c05d152"
+checksum = "c7fb8039b3032c191086b10f11f319a6e99e1e82889c5cc6046f515c9db1d497"
 
 [[package]]
 name = "rustix"
@@ -3120,9 +3142,9 @@ dependencies = [
 
 [[package]]
 name = "rustls"
-version = "0.23.10"
+version = "0.23.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05cff451f60db80f490f3c182b77c35260baace73209e9cdbbe526bfe3a4d402"
+checksum = "934b404430bb06b3fae2cba809eb45a1ab1aecd64491213d7c3301b88393f8d1"
 dependencies = [
  "log",
  "once_cell",
@@ -3135,15 +3157,15 @@ dependencies = [
 
 [[package]]
 name = "rustls-pki-types"
-version = "1.7.0"
+version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "976295e77ce332211c0d24d92c0e83e50f5c5f046d11082cea19f3df13a3562d"
+checksum = "16f1201b3c9a7ee8039bcadc17b7e605e2945b27eee7631788c1bd2b0643674b"
 
 [[package]]
 name = "rustls-webpki"
-version = "0.102.5"
+version = "0.102.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9a6fccd794a42c2c105b513a2f62bc3fd8f3ba57a4593677ceb0bd035164d78"
+checksum = "64ca1bc8749bd4cf37b5ce386cc146580777b4e8572c7b97baf22c83f444bee9"
 dependencies = [
  "ring",
  "rustls-pki-types",
@@ -3165,7 +3187,7 @@ checksum = "e86697c916019a8588c99b5fac3cead74ec0b4b819707a682fd4d23fa0ce1ba1"
 [[package]]
 name = "salsa"
 version = "0.18.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=254c749b02cde2fd29852a7463a33e800b771758#254c749b02cde2fd29852a7463a33e800b771758"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=e68679b3a9c2b5cfd8eab92de89edf4073b03601#e68679b3a9c2b5cfd8eab92de89edf4073b03601"
 dependencies = [
  "append-only-vec",
  "arc-swap",
@@ -3175,7 +3197,8 @@ dependencies = [
  "indexmap",
  "lazy_static",
  "parking_lot",
- "rustc-hash 2.0.0",
+ "rayon",
+ "rustc-hash 2.1.0",
  "salsa-macro-rules",
  "salsa-macros",
  "smallvec",
@@ -3185,17 +3208,17 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.1.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=254c749b02cde2fd29852a7463a33e800b771758#254c749b02cde2fd29852a7463a33e800b771758"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=e68679b3a9c2b5cfd8eab92de89edf4073b03601#e68679b3a9c2b5cfd8eab92de89edf4073b03601"
 
 [[package]]
 name = "salsa-macros"
 version = "0.18.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=254c749b02cde2fd29852a7463a33e800b771758#254c749b02cde2fd29852a7463a33e800b771758"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=e68679b3a9c2b5cfd8eab92de89edf4073b03601#e68679b3a9c2b5cfd8eab92de89edf4073b03601"
 dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "synstructure",
 ]
 
@@ -3229,7 +3252,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde_derive_internals",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3278,7 +3301,7 @@ checksum = "ad1e866f866923f252f05c889987993144fb74e722403468a4ebd70c3cd756c0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3289,7 +3312,7 @@ checksum = "330f01ce65a3a5fe59a60c82f3c9a024b573b8a6e875bd233fe5f934e71d54e3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3312,7 +3335,7 @@ checksum = "6c64451ba24fc7a6a2d60fc75dd9c83c90903b19028d4eff35e88fc1e86564e9"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3353,7 +3376,7 @@ dependencies = [
  "darling",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3387,9 +3410,9 @@ dependencies = [
 
 [[package]]
 name = "similar"
-version = "2.5.0"
+version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa42c91313f1d05da9b26f267f931cf178d4aba455b4c4622dd7355eb80c6640"
+checksum = "1de1d4f81173b03af4c0cbed3c898f6bff5b870e4a7f5d6f4057d62a7a4b686e"
 
 [[package]]
 name = "siphasher"
@@ -3461,7 +3484,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "rustversion",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3483,9 +3506,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.87"
+version = "2.0.90"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25aa4ce346d03a6dcd68dd8b4010bcb74e54e62c90c573f394c46eae99aba32d"
+checksum = "919d3b74a5dd0ccd15aeb8f93e7006bd9e14c295087c9896a110f490752bcf31"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3500,7 +3523,7 @@ checksum = "c8af7666ab7b6390ab78131fb5b0fce11d6b7a6951602017c35fa82800708971"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3563,7 +3586,7 @@ dependencies = [
  "cfg-if",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3574,7 +3597,7 @@ checksum = "5c89e72a01ed4c579669add59014b9a524d609c0c88c6a585ce37485879f6ffb"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "test-case-core",
 ]
 
@@ -3604,7 +3627,7 @@ checksum = "b607164372e89797d78b8e23a6d67d5d1038c1c65efd52e1389ef8b77caba2a6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3615,7 +3638,7 @@ checksum = "f077553d607adc1caf65430528a576c757a71ed73944b66ebb58ef2bbd243568"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -3719,9 +3742,9 @@ dependencies = [
 
 [[package]]
 name = "tracing"
-version = "0.1.40"
+version = "0.1.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3523ab5a71916ccf420eebdf5521fcef02141234bbc0b8a49f2fdc4544364ef"
+checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
 dependencies = [
  "log",
  "pin-project-lite",
@@ -3731,20 +3754,20 @@ dependencies = [
 
 [[package]]
 name = "tracing-attributes"
-version = "0.1.27"
+version = "0.1.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
+checksum = "395ae124c09f9e6918a2310af6038fba074bcf474ac352496d5910dd59a2226d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
 name = "tracing-core"
-version = "0.1.32"
+version = "0.1.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c06d3da6113f116aaee68e4d601191614c9053067f9ab7f6edbcb161237daa54"
+checksum = "e672c95779cf947c5311f83787af4fa8fffd12fb27e4993211a84bdfd9610f9c"
 dependencies = [
  "once_cell",
  "valuable",
@@ -3786,9 +3809,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-subscriber"
-version = "0.3.18"
+version = "0.3.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad0f048c97dbd9faa9b7df56362b8ebcaa52adb06b498c050d2f4e32f90a7a8b"
+checksum = "e8189decb5ac0fa7bc8b96b7cb9b2701d60d48805aca84a238004d665fcc4008"
 dependencies = [
  "matchers",
  "nu-ansi-term 0.46.0",
@@ -3876,9 +3899,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.13"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+checksum = "adb9e6ca4f869e1180728b7950e35922a7fc6397f7b641499e8f3ef06e50dc83"
 
 [[package]]
 name = "unicode-normalization"
@@ -3937,25 +3960,28 @@ checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
 
 [[package]]
 name = "ureq"
-version = "2.10.1"
+version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b74fc6b57825be3373f7054754755f03ac3a8f5d70015ccad699ba2029956f4a"
+checksum = "b30e6f97efe1fa43535ee241ee76967d3ff6ff3953ebb430d8d55c5393029e7b"
 dependencies = [
  "base64 0.22.0",
  "flate2",
+ "litemap",
  "log",
  "once_cell",
  "rustls",
  "rustls-pki-types",
  "url",
  "webpki-roots",
+ "yoke",
+ "zerofrom",
 ]
 
 [[package]]
 name = "url"
-version = "2.5.3"
+version = "2.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d157f1b96d14500ffdc1f10ba712e780825526c03d9a49b4d0324b0d9113ada"
+checksum = "32f8b686cadd1473f4bd0117a5d28d36b1ade384ea9b5069a1c40aefed7fda60"
 dependencies = [
  "form_urlencoded",
  "idna",
@@ -4007,7 +4033,7 @@ checksum = "6b91f57fe13a38d0ce9e28a03463d8d3c2468ed03d75375110ec71d93b449a08"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -4082,9 +4108,9 @@ checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "128d1e363af62632b8eb57219c8fd7877144af57558fb2ef0368d0087bddeb2e"
+checksum = "d15e63b4482863c109d70a7b8706c1e364eb6ea449b201a76c5b89cedcec2d5c"
 dependencies = [
  "cfg-if",
  "once_cell",
@@ -4093,36 +4119,37 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-backend"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cb6dd4d3ca0ddffd1dd1c9c04f94b868c37ff5fac97c30b97cff2d74fce3a358"
+checksum = "8d36ef12e3aaca16ddd3f67922bc63e48e953f126de60bd33ccc0101ef9998cd"
 dependencies = [
  "bumpalo",
  "log",
  "once_cell",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "wasm-bindgen-shared",
 ]
 
 [[package]]
 name = "wasm-bindgen-futures"
-version = "0.4.45"
+version = "0.4.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc7ec4f8827a71586374db3e87abdb5a2bb3a15afed140221307c3ec06b1f63b"
+checksum = "9dfaf8f50e5f293737ee323940c7d8b08a66a95a419223d9f41610ca08b0833d"
 dependencies = [
  "cfg-if",
  "js-sys",
+ "once_cell",
  "wasm-bindgen",
  "web-sys",
 ]
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e79384be7f8f5a9dd5d7167216f022090cf1f9ec128e6e6a482a2cb5c5422c56"
+checksum = "705440e08b42d3e4b36de7d66c944be628d579796b8090bfa3471478a2260051"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -4130,32 +4157,32 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "26c6ab57572f7a24a4985830b120de1594465e5d500f24afe89e16b4e833ef68"
+checksum = "98c9ae5a76e46f4deecd0f0255cc223cfa18dc9b261213b8aa0c7b36f61b3f1d"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.95"
+version = "0.2.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65fc09f10666a9f147042251e0dda9c18f166ff7de300607007e96bdebc1068d"
+checksum = "6ee99da9c5ba11bd675621338ef6fa52296b76b83305e9b6e5c77d4c286d6d49"
 
 [[package]]
 name = "wasm-bindgen-test"
-version = "0.3.45"
+version = "0.3.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d381749acb0943d357dcbd8f0b100640679883fcdeeef04def49daf8d33a5426"
+checksum = "3d919bb60ebcecb9160afee6c71b43a58a4f0517a2de0054cd050d02cec08201"
 dependencies = [
- "console_error_panic_hook",
  "js-sys",
  "minicov",
+ "once_cell",
  "scoped-tls",
  "wasm-bindgen",
  "wasm-bindgen-futures",
@@ -4164,20 +4191,20 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-test-macro"
-version = "0.3.45"
+version = "0.3.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c97b2ef2c8d627381e51c071c2ab328eac606d3f69dd82bcbca20a9e389d95f0"
+checksum = "222ebde6ea87fbfa6bdd2e9f1fd8a91d60aee5db68792632176c4e16a74fc7d8"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
 name = "web-sys"
-version = "0.3.69"
+version = "0.3.74"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77afa9a11836342370f4817622a2f0f418b134426d91a82dfb48f532d2ec13ef"
+checksum = "a98bc3c33f0fe7e59ad7cd041b89034fa82a7c2d4365ca538dda6cdaf513863c"
 dependencies = [
  "js-sys",
  "wasm-bindgen",
@@ -4473,7 +4500,7 @@ checksum = "28cc31741b18cb6f1d5ff12f5b7523e3d6eb0852bbbad19d73905511d9849b95"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "synstructure",
 ]
 
@@ -4494,7 +4521,7 @@ checksum = "9ce1b18ccd8e73a9321186f97e46f9f04b778851177567b1975109d26a08d2a6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]
@@ -4514,7 +4541,7 @@ checksum = "0ea7b4a3637ea8669cedf0f1fd5c286a17f3de97b8dd5a70a6c167a1730e63a5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
  "synstructure",
 ]
 
@@ -4543,7 +4570,7 @@ checksum = "6eafa6dfb17584ea3e2bd6e76e0cc15ad7af12b09abdd1ca55961bed9b1063c6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.90",
 ]
 
 [[package]]

Cargo.toml

@@ -65,7 +65,7 @@ compact_str = "0.8.0"
 criterion = { version = "0.5.1", default-features = false }
 crossbeam = { version = "0.8.4" }
 dashmap = { version = "6.0.1" }
-dir-test = { version = "0.3.0" }
+dir-test = { version = "0.4.0" }
 dunce = { version = "1.0.5" }
 drop_bomb = { version = "0.1.5" }
 env_logger = { version = "0.11.0" }
@@ -118,7 +118,7 @@ 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/salsa-rs/salsa.git", rev = "254c749b02cde2fd29852a7463a33e800b771758" }
+salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "e68679b3a9c2b5cfd8eab92de89edf4073b03601" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }

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/0.8.0/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.8.0/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.8.1/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.8.1/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -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: v0.8.0
+  rev: v0.8.1
   hooks:
     # Run the linter.
     - id: ruff

clippy.toml

@@ -1,21 +1,25 @@
 doc-valid-idents = [
-  "..",
-  "CodeQL",
-  "FastAPI",
-  "IPython",
-  "LangChain",
-  "LibCST",
-  "McCabe",
-  "NumPy",
-  "SCREAMING_SNAKE_CASE",
-  "SQLAlchemy",
-  "StackOverflow",
-  "PyCharm",
+    "..",
+    "CodeQL",
+    "FastAPI",
+    "IPython",
+    "LangChain",
+    "LibCST",
+    "McCabe",
+    "NumPy",
+    "SCREAMING_SNAKE_CASE",
+    "SQLAlchemy",
+    "StackOverflow",
+    "PyCharm",
+    "SNMPv1",
+    "SNMPv2",
+    "SNMPv3",
+    "PyFlakes"
 ]
 
 ignore-interior-mutability = [
-  # Interned is read-only. The wrapped `Rc` never gets updated.
-  "ruff_formatter::format_element::Interned",
-  # The expression is read-only.
-  "ruff_python_ast::hashable::HashableExpr",
+    # Interned is read-only. The wrapped `Rc` never gets updated.
+    "ruff_formatter::format_element::Interned",
+    # The expression is read-only.
+    "ruff_python_ast::hashable::HashableExpr",
 ]

crates/red_knot/docs/tracing.md

@@ -103,7 +103,7 @@ called **once**.
 
 ## Profiling
 
-Red Knot generates a folded stack trace  to the current directory named `tracing.folded` when setting the environment variable `RED_KNOT_LOG_PROFILE` to `1` or `true`.
+Red Knot generates a folded stack trace to the current directory named `tracing.folded` when setting the environment variable `RED_KNOT_LOG_PROFILE` to `1` or `true`.
 
 ```bash
 RED_KNOT_LOG_PROFILE=1 red_knot -- --current-directory=../test -vvv

crates/red_knot/src/main.rs

@@ -12,7 +12,7 @@ use red_knot_workspace::watch;
 use red_knot_workspace::watch::WorkspaceWatcher;
 use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
-use ruff_db::diagnostic::Diagnostic;
+use ruff_db::diagnostic::CompileDiagnostic;
 use ruff_db::system::{OsSystem, System, SystemPath, SystemPathBuf};
 use salsa::plumbing::ZalsaDatabase;
 use target_version::TargetVersion;
@@ -297,7 +297,7 @@ impl MainLoop {
         while let Ok(message) = self.receiver.recv() {
             match message {
                 MainLoopMessage::CheckWorkspace => {
-                    let db = db.snapshot();
+                    let db = db.clone();
                     let sender = self.sender.clone();
 
                     // Spawn a new task that checks the workspace. This needs to be done in a separate thread
@@ -380,7 +380,7 @@ impl MainLoopCancellationToken {
 enum MainLoopMessage {
     CheckWorkspace,
     CheckCompleted {
-        result: Vec<Box<dyn Diagnostic>>,
+        result: Vec<CompileDiagnostic>,
         revision: u64,
     },
     ApplyChanges(Vec<watch::ChangeEvent>),

crates/red_knot/tests/file_watching.rs

@@ -1,26 +1,23 @@
 #![allow(clippy::disallowed_names)]
 
 use std::io::Write;
-use std::time::Duration;
+use std::time::{Duration, Instant};
 
 use anyhow::{anyhow, Context};
-
 use red_knot_python_semantic::{resolve_module, ModuleName, Program, PythonVersion, SitePackages};
 use red_knot_workspace::db::{Db, RootDatabase};
-use red_knot_workspace::watch;
-use red_knot_workspace::watch::{directory_watcher, WorkspaceWatcher};
+use red_knot_workspace::watch::{directory_watcher, ChangeEvent, WorkspaceWatcher};
 use red_knot_workspace::workspace::settings::{Configuration, SearchPathConfiguration};
 use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File, FileError};
 use ruff_db::source::source_text;
 use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
-use ruff_db::testing::setup_logging;
 use ruff_db::Upcast;
 
 struct TestCase {
     db: RootDatabase,
     watcher: Option<WorkspaceWatcher>,
-    changes_receiver: crossbeam::channel::Receiver<Vec<watch::ChangeEvent>>,
+    changes_receiver: crossbeam::channel::Receiver<Vec<ChangeEvent>>,
     /// The temporary directory that contains the test files.
     /// We need to hold on to it in the test case or the temp files get deleted.
     _temp_dir: tempfile::TempDir,
@@ -41,44 +38,87 @@ impl TestCase {
         &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")
+    #[track_caller]
+    fn stop_watch<M>(&mut self, matcher: M) -> Vec<ChangeEvent>
+    where
+        M: MatchEvent,
+    {
+        // track_caller is unstable for lambdas -> That's why this is a fn
+        #[track_caller]
+        fn panic_with_formatted_events(events: Vec<ChangeEvent>) -> Vec<ChangeEvent> {
+            panic!(
+                "Didn't observe expected change:\n{}",
+                events
+                    .into_iter()
+                    .map(|event| format!("  - {event:?}"))
+                    .collect::<Vec<_>>()
+                    .join("\n")
+            )
+        }
+
+        self.try_stop_watch(matcher, Duration::from_secs(10))
+            .unwrap_or_else(panic_with_formatted_events)
     }
 
-    fn try_stop_watch(&mut self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
+    fn try_stop_watch<M>(
+        &mut self,
+        mut matcher: M,
+        timeout: Duration,
+    ) -> Result<Vec<ChangeEvent>, Vec<ChangeEvent>>
+    where
+        M: MatchEvent,
+    {
+        tracing::debug!("Try stopping watch with timeout {:?}", timeout);
+
         let watcher = self
             .watcher
             .take()
             .expect("Cannot call `stop_watch` more than once");
 
-        let mut all_events = self
-            .changes_receiver
-            .recv_timeout(timeout)
-            .unwrap_or_default();
-        watcher.flush();
-        watcher.stop();
+        let start = Instant::now();
+        let mut all_events = Vec::new();
 
+        loop {
+            let events = self
+                .changes_receiver
+                .recv_timeout(Duration::from_millis(100))
+                .unwrap_or_default();
+
+            if events
+                .iter()
+                .any(|event| matcher.match_event(event) || event.is_rescan())
+            {
+                all_events.extend(events);
+                break;
+            }
+
+            all_events.extend(events);
+
+            if start.elapsed() > timeout {
+                return Err(all_events);
+            }
+        }
+
+        watcher.flush();
+        tracing::debug!("Flushed file watcher");
+        watcher.stop();
+        tracing::debug!("Stopping file watcher");
+
+        // Consume remaining events
         for event in &self.changes_receiver {
             all_events.extend(event);
         }
 
-        if all_events.is_empty() {
-            return None;
-        }
-
-        Some(all_events)
+        Ok(all_events)
     }
 
-    fn take_watch_changes(&self) -> Vec<watch::ChangeEvent> {
+    fn take_watch_changes(&self) -> Vec<ChangeEvent> {
         self.try_take_watch_changes(Duration::from_secs(10))
             .expect("Expected watch changes but observed none")
     }
 
-    fn try_take_watch_changes(&self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
-        let Some(watcher) = &self.watcher else {
-            return None;
-        };
+    fn try_take_watch_changes(&self, timeout: Duration) -> Option<Vec<ChangeEvent>> {
+        let watcher = self.watcher.as_ref()?;
 
         let mut all_events = self
             .changes_receiver
@@ -100,7 +140,7 @@ impl TestCase {
         Some(all_events)
     }
 
-    fn apply_changes(&mut self, changes: Vec<watch::ChangeEvent>) {
+    fn apply_changes(&mut self, changes: Vec<ChangeEvent>) {
         self.db.apply_changes(changes, Some(&self.configuration));
     }
 
@@ -136,6 +176,23 @@ impl TestCase {
     }
 }
 
+trait MatchEvent {
+    fn match_event(&mut self, event: &ChangeEvent) -> bool;
+}
+
+fn event_for_file(name: &str) -> impl MatchEvent + '_ {
+    |event: &ChangeEvent| event.file_name() == Some(name)
+}
+
+impl<F> MatchEvent for F
+where
+    F: FnMut(&ChangeEvent) -> bool,
+{
+    fn match_event(&mut self, event: &ChangeEvent) -> bool {
+        (*self)(event)
+    }
+}
+
 trait SetupFiles {
     fn setup(self, root_path: &SystemPath, workspace_path: &SystemPath) -> anyhow::Result<()>;
 }
@@ -311,7 +368,7 @@ fn new_file() -> anyhow::Result<()> {
 
     std::fs::write(foo_path.as_std_path(), "print('Hello')")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -334,7 +391,7 @@ fn new_ignored_file() -> anyhow::Result<()> {
 
     std::fs::write(foo_path.as_std_path(), "print('Hello')")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -356,7 +413,7 @@ fn changed_file() -> anyhow::Result<()> {
 
     update_file(&foo_path, "print('Version 2')")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     assert!(!changes.is_empty());
 
@@ -381,7 +438,7 @@ fn deleted_file() -> anyhow::Result<()> {
 
     std::fs::remove_file(foo_path.as_std_path())?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -413,7 +470,7 @@ fn move_file_to_trash() -> anyhow::Result<()> {
         trash_path.join("foo.py").as_std_path(),
     )?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -445,7 +502,7 @@ fn move_file_to_workspace() -> anyhow::Result<()> {
 
     std::fs::rename(foo_path.as_std_path(), foo_in_workspace_path.as_std_path())?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -473,7 +530,7 @@ fn rename_file() -> anyhow::Result<()> {
 
     std::fs::rename(foo_path.as_std_path(), bar_path.as_std_path())?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("bar.py"));
 
     case.apply_changes(changes);
 
@@ -517,7 +574,7 @@ fn directory_moved_to_workspace() -> anyhow::Result<()> {
     std::fs::rename(sub_original_path.as_std_path(), sub_new_path.as_std_path())
         .with_context(|| "Failed to move sub directory")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("sub"));
 
     case.apply_changes(changes);
 
@@ -576,7 +633,7 @@ fn directory_moved_to_trash() -> anyhow::Result<()> {
     std::fs::rename(sub_path.as_std_path(), trashed_sub.as_std_path())
         .with_context(|| "Failed to move the sub directory to the trash")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("sub"));
 
     case.apply_changes(changes);
 
@@ -638,7 +695,8 @@ fn directory_renamed() -> anyhow::Result<()> {
     std::fs::rename(sub_path.as_std_path(), foo_baz.as_std_path())
         .with_context(|| "Failed to move the sub directory")?;
 
-    let changes = case.stop_watch();
+    // Linux and windows only emit an event for the newly created root directory, but not for every new component.
+    let changes = case.stop_watch(event_for_file("sub"));
 
     case.apply_changes(changes);
 
@@ -711,7 +769,7 @@ fn directory_deleted() -> anyhow::Result<()> {
     std::fs::remove_dir_all(sub_path.as_std_path())
         .with_context(|| "Failed to remove the sub directory")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("sub"));
 
     case.apply_changes(changes);
 
@@ -748,7 +806,7 @@ fn search_path() -> anyhow::Result<()> {
 
     std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("a.py"));
 
     case.apply_changes(changes);
 
@@ -779,7 +837,7 @@ fn add_search_path() -> anyhow::Result<()> {
 
     std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("a.py"));
 
     case.apply_changes(changes);
 
@@ -808,9 +866,9 @@ fn remove_search_path() -> anyhow::Result<()> {
 
     std::fs::write(site_packages.join("a.py").as_std_path(), "class A: ...")?;
 
-    let changes = case.try_stop_watch(Duration::from_millis(100));
+    let changes = case.try_stop_watch(|_: &ChangeEvent| true, Duration::from_millis(100));
 
-    assert_eq!(changes, None);
+    assert_eq!(changes, Err(vec![]));
 
     Ok(())
 }
@@ -848,7 +906,7 @@ fn changed_versions_file() -> anyhow::Result<()> {
         "os: 3.0-",
     )?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("VERSIONS"));
 
     case.apply_changes(changes);
 
@@ -901,7 +959,7 @@ fn hard_links_in_workspace() -> anyhow::Result<()> {
     // Write to the hard link target.
     update_file(foo_path, "print('Version 2')").context("Failed to update foo.py")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("foo.py"));
 
     case.apply_changes(changes);
 
@@ -972,7 +1030,7 @@ fn hard_links_to_target_outside_workspace() -> anyhow::Result<()> {
     // Write to the hard link target.
     update_file(foo_path, "print('Version 2')").context("Failed to update foo.py")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(ChangeEvent::is_changed);
 
     case.apply_changes(changes);
 
@@ -1011,7 +1069,7 @@ mod unix {
         )
         .with_context(|| "Failed to set file permissions.")?;
 
-        let changes = case.stop_watch();
+        let changes = case.stop_watch(event_for_file("foo.py"));
 
         case.apply_changes(changes);
 
@@ -1109,7 +1167,7 @@ mod unix {
         update_file(baz_workspace, "def baz(): print('Version 3')")
             .context("Failed to update bar/baz.py")?;
 
-        let changes = case.stop_watch();
+        let changes = case.stop_watch(event_for_file("baz.py"));
 
         case.apply_changes(changes);
 
@@ -1180,7 +1238,7 @@ mod unix {
         update_file(&patched_bar_baz, "def baz(): print('Version 2')")
             .context("Failed to update bar/baz.py")?;
 
-        let changes = case.stop_watch();
+        let changes = case.stop_watch(event_for_file("baz.py"));
 
         case.apply_changes(changes);
 
@@ -1288,7 +1346,7 @@ mod unix {
         update_file(&baz_original, "def baz(): print('Version 2')")
             .context("Failed to update bar/baz.py")?;
 
-        let changes = case.stop_watch();
+        let changes = case.stop_watch(event_for_file("baz.py"));
 
         case.apply_changes(changes);
 
@@ -1342,7 +1400,7 @@ fn nested_packages_delete_root() -> anyhow::Result<()> {
 
     std::fs::remove_file(case.workspace_path("pyproject.toml").as_std_path())?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(ChangeEvent::is_deleted);
 
     case.apply_changes(changes);
 
@@ -1354,7 +1412,6 @@ fn nested_packages_delete_root() -> anyhow::Result<()> {
 
 #[test]
 fn added_package() -> anyhow::Result<()> {
-    let _ = setup_logging();
     let mut case = setup([
         (
             "pyproject.toml",
@@ -1396,7 +1453,7 @@ fn added_package() -> anyhow::Result<()> {
     )
     .context("failed to write pyproject.toml for package b")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(event_for_file("pyproject.toml"));
 
     case.apply_changes(changes);
 
@@ -1439,7 +1496,7 @@ fn removed_package() -> anyhow::Result<()> {
     std::fs::remove_dir_all(case.workspace_path("packages/b").as_std_path())
         .context("failed to remove package 'b'")?;
 
-    let changes = case.stop_watch();
+    let changes = case.stop_watch(ChangeEvent::is_deleted);
 
     case.apply_changes(changes);
 

crates/red_knot_python_semantic/Cargo.toml

@@ -49,6 +49,8 @@ anyhow = { workspace = true }
 dir-test = { workspace = true }
 insta = { workspace = true }
 tempfile = { workspace = true }
+quickcheck = { version = "1.0.3", default-features = false }
+quickcheck_macros = { version = "1.0.0" }
 
 [lints]
 workspace = true

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

@@ -0,0 +1,128 @@
+# `LiteralString`
+
+`LiteralString` represents a string that is either defined directly within the source code or is
+made up of such components.
+
+Parts of the testcases defined here were adapted from [the specification's examples][1].
+
+## Usages
+
+### Valid places
+
+It can be used anywhere a type is accepted:
+
+```py
+from typing import LiteralString
+
+x: LiteralString
+
+def f():
+    reveal_type(x)  # revealed: LiteralString
+```
+
+### Within `Literal`
+
+`LiteralString` cannot be used within `Literal`:
+
+```py
+from typing import Literal, LiteralString
+
+bad_union: Literal["hello", LiteralString]  # error: [invalid-literal-parameter]
+bad_nesting: Literal[LiteralString]  # error: [invalid-literal-parameter]
+```
+
+### Parametrized
+
+`LiteralString` cannot be parametrized.
+
+```py
+from typing import LiteralString
+
+a: LiteralString[str]  # error: [invalid-type-parameter]
+b: LiteralString["foo"]  # error: [invalid-type-parameter]
+```
+
+### As a base class
+
+Subclassing `LiteralString` leads to a runtime error.
+
+```py
+from typing import LiteralString
+
+class C(LiteralString): ...  # error: [invalid-base]
+```
+
+## Inference
+
+### Common operations
+
+```py
+foo: LiteralString = "foo"
+reveal_type(foo)  # revealed: Literal["foo"]
+
+bar: LiteralString = "bar"
+reveal_type(foo + bar)  # revealed: Literal["foobar"]
+
+baz: LiteralString = "baz"
+baz += foo
+reveal_type(baz)  # revealed: Literal["bazfoo"]
+
+qux = (foo, bar)
+reveal_type(qux)  # revealed: tuple[Literal["foo"], Literal["bar"]]
+
+# TODO: Infer "LiteralString"
+reveal_type(foo.join(qux))  # revealed: @Todo(call todo)
+
+template: LiteralString = "{}, {}"
+reveal_type(template)  # revealed: Literal["{}, {}"]
+# TODO: Infer `LiteralString`
+reveal_type(template.format(foo, bar))  # revealed: @Todo(call todo)
+```
+
+### Assignability
+
+`Literal[""]` is assignable to `LiteralString`, and `LiteralString` is assignable to `str`, but not
+vice versa.
+
+```py
+def coinflip() -> bool:
+    return True
+
+foo_1: Literal["foo"] = "foo"
+bar_1: LiteralString = foo_1  # fine
+
+foo_2 = "foo" if coinflip() else "bar"
+reveal_type(foo_2)  # revealed: Literal["foo", "bar"]
+bar_2: LiteralString = foo_2  # fine
+
+foo_3: LiteralString = "foo" * 1_000_000_000
+bar_3: str = foo_2  # fine
+
+baz_1: str = str()
+qux_1: LiteralString = baz_1  # error: [invalid-assignment]
+
+baz_2: LiteralString = "baz" * 1_000_000_000
+qux_2: Literal["qux"] = baz_2  # error: [invalid-assignment]
+
+baz_3 = "foo" if coinflip() else 1
+reveal_type(baz_3)  # revealed: Literal["foo"] | Literal[1]
+qux_3: LiteralString = baz_3  # error: [invalid-assignment]
+```
+
+### Narrowing
+
+```py
+lorem: LiteralString = "lorem" * 1_000_000_000
+
+reveal_type(lorem)  # revealed: LiteralString
+
+if lorem == "ipsum":
+    reveal_type(lorem)  # revealed: Literal["ipsum"]
+
+reveal_type(lorem)  # revealed: LiteralString
+
+if "" < lorem == "ipsum":
+    reveal_type(lorem)  # revealed: Literal["ipsum"]
+```
+
+[1]: https://typing.readthedocs.io/en/latest/spec/literal.html#literalstring

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

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

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

@@ -189,3 +189,31 @@ reveal_type(d)  # revealed: Foo
 ## Parameter
 
 TODO: Add tests once parameter inference is supported
+
+## Invalid expressions
+
+The expressions in these string annotations aren't valid expressions in this context but we
+shouldn't panic.
+
+```py
+a: "1 or 2"
+b: "(x := 1)"
+c: "1 + 2"
+d: "lambda x: x"
+e: "x if True else y"
+f: "{'a': 1, 'b': 2}"
+g: "{1, 2}"
+h: "[i for i in range(5)]"
+i: "{i for i in range(5)}"
+j: "{i: i for i in range(5)}"
+k: "(i for i in range(5))"
+l: "await 1"
+# error: [forward-annotation-syntax-error]
+m: "yield 1"
+# error: [forward-annotation-syntax-error]
+n: "yield from 1"
+o: "1 < 2"
+p: "call()"
+r: "[1, 2]"
+s: "(1, 2)"
+```

crates/red_knot_python_semantic/resources/mdtest/expression/if.md

@@ -22,3 +22,22 @@ reveal_type(1 if None else 2)  # revealed: Literal[2]
 reveal_type(1 if "" else 2)  # revealed: Literal[2]
 reveal_type(1 if 0 else 2)  # revealed: Literal[2]
 ```
+
+## Leaked Narrowing Constraint
+
+(issue #14588)
+
+The test inside an if expression should not affect code outside of the expression.
+
+```py
+def bool_instance() -> bool:
+    return True
+
+x: Literal[42, "hello"] = 42 if bool_instance() else "hello"
+
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+
+_ = ... if isinstance(x, str) else ...
+
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+```

crates/red_knot_python_semantic/resources/mdtest/generics.md

@@ -60,52 +60,20 @@ reveal_type(S)  # revealed: Literal[S]
 
 ## Type params
 
-A PEP695 type variable defines a value of type `typing.TypeVar` with attributes `__name__`,
-`__bounds__`, `__constraints__`, and `__default__` (the latter three all lazily evaluated):
+A PEP695 type variable defines a value of type `typing.TypeVar`.
 
 ```py
-def f[T, U: A, V: (A, B), W = A, X: A = A1]():
+def f[T]():
     reveal_type(T)  # revealed: T
     reveal_type(T.__name__)  # revealed: Literal["T"]
-    reveal_type(T.__bound__)  # revealed: None
-    reveal_type(T.__constraints__)  # revealed: tuple[()]
-    reveal_type(T.__default__)  # revealed: NoDefault
-
-    reveal_type(U)  # revealed: U
-    reveal_type(U.__name__)  # revealed: Literal["U"]
-    reveal_type(U.__bound__)  # revealed: type[A]
-    reveal_type(U.__constraints__)  # revealed: tuple[()]
-    reveal_type(U.__default__)  # revealed: NoDefault
-
-    reveal_type(V)  # revealed: V
-    reveal_type(V.__name__)  # revealed: Literal["V"]
-    reveal_type(V.__bound__)  # revealed: None
-    reveal_type(V.__constraints__)  # revealed: tuple[type[A], type[B]]
-    reveal_type(V.__default__)  # revealed: NoDefault
-
-    reveal_type(W)  # revealed: W
-    reveal_type(W.__name__)  # revealed: Literal["W"]
-    reveal_type(W.__bound__)  # revealed: None
-    reveal_type(W.__constraints__)  # revealed: tuple[()]
-    reveal_type(W.__default__)  # revealed: type[A]
-
-    reveal_type(X)  # revealed: X
-    reveal_type(X.__name__)  # revealed: Literal["X"]
-    reveal_type(X.__bound__)  # revealed: type[A]
-    reveal_type(X.__constraints__)  # revealed: tuple[()]
-    reveal_type(X.__default__)  # revealed: type[A1]
-
-class A: ...
-class B: ...
-class A1(A): ...
 ```
 
 ## Minimum two constraints
 
-A typevar with less than two constraints emits a diagnostic and is treated as unconstrained:
+A typevar with less than two constraints emits a diagnostic:
 
 ```py
 # error: [invalid-typevar-constraints] "TypeVar must have at least two constrained types"
 def f[T: (int,)]():
-    reveal_type(T.__constraints__)  # revealed: tuple[()]
+    pass
 ```

crates/red_knot_python_semantic/resources/mdtest/loops/while_loop.md

@@ -52,3 +52,29 @@ else:
 reveal_type(x)  # revealed: Literal[2, 3]
 reveal_type(y)  # revealed: Literal[1, 2, 4]
 ```
+
+## Nested while loops
+
+```py
+def flag() -> bool:
+    return True
+
+x = 1
+
+while flag():
+    x = 2
+
+    while flag():
+        x = 3
+        if flag():
+            break
+    else:
+        x = 4
+
+    if flag():
+        break
+else:
+    x = 5
+
+reveal_type(x)  # revealed: Literal[3, 4, 5]
+```

crates/red_knot_python_semantic/resources/mdtest/mro.md

@@ -256,7 +256,7 @@ class O: ...
 class X(O): ...
 class Y(O): ...
 
-if bool():
+if returns_bool():
     foo = Y
 else:
     foo = object

crates/red_knot_python_semantic/resources/mdtest/narrow/bool-call.md

@@ -0,0 +1,32 @@
+## Narrowing for `bool(..)` checks
+
+```py
+def flag() -> bool: ...
+
+x = 1 if flag() else None
+
+# valid invocation, positive
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None):
+    reveal_type(x)  # revealed: Literal[1]
+
+# valid invocation, negative
+reveal_type(x)  # revealed: Literal[1] | None
+if not bool(x is not None):
+    reveal_type(x)  # revealed: None
+
+# no args/narrowing
+reveal_type(x)  # revealed: Literal[1] | None
+if not bool():
+    reveal_type(x)  # revealed: Literal[1] | None
+
+# invalid invocation, too many positional args
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None, 5):  # TODO diagnostic
+    reveal_type(x)  # revealed: Literal[1] | None
+
+# invalid invocation, too many kwargs
+reveal_type(x)  # revealed: Literal[1] | None
+if bool(x is not None, y=5):  # TODO diagnostic
+    reveal_type(x)  # revealed: Literal[1] | None
+```

crates/red_knot_python_semantic/resources/mdtest/narrow/post_if_statement.md

@@ -0,0 +1,64 @@
+# Consolidating narrowed types after if statement
+
+## After if-else statements, narrowing has no effect if the variable is not mutated in any branch
+
+```py
+def optional_int() -> int | None: ...
+
+x = optional_int()
+
+if x is None:
+    pass
+else:
+    pass
+
+reveal_type(x)  # revealed: int | None
+```
+
+## Narrowing can have a persistent effect if the variable is mutated in one branch
+
+```py
+def optional_int() -> int | None: ...
+
+x = optional_int()
+
+if x is None:
+    x = 10
+else:
+    pass
+
+reveal_type(x)  # revealed: int
+```
+
+## An if statement without an explicit `else` branch is equivalent to one with a no-op `else` branch
+
+```py
+def optional_int() -> int | None: ...
+
+x = optional_int()
+y = optional_int()
+
+if x is None:
+    x = 0
+
+if y is None:
+    pass
+
+reveal_type(x)  # revealed: int
+reveal_type(y)  # revealed: int | None
+```
+
+## An if-elif without an explicit else branch is equivalent to one with an empty else branch
+
+```py
+def optional_int() -> int | None: ...
+
+x = optional_int()
+
+if x is None:
+    x = 0
+elif x > 50:
+    x = 50
+
+reveal_type(x)  # revealed: int
+```

crates/red_knot_python_semantic/resources/mdtest/subscript/class.md

@@ -21,10 +21,11 @@ reveal_type(Identity[0])  # revealed: str
 ## Class getitem union
 
 ```py
-flag = True
+def bool_instance() -> bool:
+    return True
 
 class UnionClassGetItem:
-    if flag:
+    if bool_instance():
 
         def __class_getitem__(cls, item: int) -> str:
             return item
@@ -59,9 +60,10 @@ reveal_type(x[0])  # revealed: str | int
 ## Class getitem with unbound method union
 
 ```py
-flag = True
+def bool_instance() -> bool:
+    return True
 
-if flag:
+if bool_instance():
     class Spam:
         def __class_getitem__(self, x: int) -> str:
             return "foo"
@@ -77,9 +79,10 @@ reveal_type(Spam[42])
 ## TODO: Class getitem non-class union
 
 ```py
-flag = True
+def bool_instance() -> bool:
+    return True
 
-if flag:
+if bool_instance():
     class Eggs:
         def __class_getitem__(self, x: int) -> str:
             return "foo"

crates/red_knot_python_semantic/resources/mdtest/subscript/instance.md

@@ -30,10 +30,11 @@ reveal_type(Identity()[0])  # revealed: int
 ## Getitem union
 
 ```py
-flag = True
+def bool_instance() -> bool:
+    return True
 
 class Identity:
-    if flag:
+    if bool_instance():
 
         def __getitem__(self, index: int) -> int:
             return index

crates/red_knot_python_semantic/src/db.rs

@@ -19,6 +19,7 @@ pub(crate) mod tests {
     use super::Db;
 
     #[salsa::db]
+    #[derive(Clone)]
     pub(crate) struct TestDb {
         storage: salsa::Storage<Self>,
         files: Files,

crates/red_knot_python_semantic/src/module_resolver/resolver.rs

@@ -416,7 +416,7 @@ impl<'db> Iterator for SearchPathIterator<'db> {
     }
 }
 
-impl<'db> FusedIterator for SearchPathIterator<'db> {}
+impl FusedIterator for SearchPathIterator<'_> {}
 
 /// Represents a single `.pth` file in a `site-packages` directory.
 /// One or more lines in a `.pth` file may be a (relative or absolute)

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -36,12 +36,25 @@ use super::definition::{
 
 mod except_handlers;
 
+/// Are we in a state where a `break` statement is allowed?
+#[derive(Clone, Copy, Debug)]
+enum LoopState {
+    InLoop,
+    NotInLoop,
+}
+
+impl LoopState {
+    fn is_inside(self) -> bool {
+        matches!(self, LoopState::InLoop)
+    }
+}
+
 pub(super) struct SemanticIndexBuilder<'db> {
     // Builder state
     db: &'db dyn Db,
     file: File,
     module: &'db ParsedModule,
-    scope_stack: Vec<FileScopeId>,
+    scope_stack: Vec<(FileScopeId, LoopState)>,
     /// The assignments we're currently visiting, with
     /// the most recent visit at the end of the Vec
     current_assignments: Vec<CurrentAssignment<'db>>,
@@ -103,9 +116,24 @@ impl<'db> SemanticIndexBuilder<'db> {
         *self
             .scope_stack
             .last()
+            .map(|(scope, _)| scope)
             .expect("Always to have a root scope")
     }
 
+    fn loop_state(&self) -> LoopState {
+        self.scope_stack
+            .last()
+            .expect("Always to have a root scope")
+            .1
+    }
+
+    fn set_inside_loop(&mut self, state: LoopState) {
+        self.scope_stack
+            .last_mut()
+            .expect("Always to have a root scope")
+            .1 = state;
+    }
+
     fn push_scope(&mut self, node: NodeWithScopeRef) {
         let parent = self.current_scope();
         self.push_scope_with_parent(node, Some(parent));
@@ -136,11 +164,11 @@ impl<'db> SemanticIndexBuilder<'db> {
 
         debug_assert_eq!(ast_id_scope, file_scope_id);
 
-        self.scope_stack.push(file_scope_id);
+        self.scope_stack.push((file_scope_id, LoopState::NotInLoop));
     }
 
     fn pop_scope(&mut self) -> FileScopeId {
-        let id = self.scope_stack.pop().expect("Root scope to be present");
+        let (id, _) = self.scope_stack.pop().expect("Root scope to be present");
         let children_end = self.scopes.next_index();
         let scope = &mut self.scopes[id];
         scope.descendents = scope.descendents.start..children_end;
@@ -286,10 +314,6 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.current_assignments.last().copied()
     }
 
-    fn current_assignment_mut(&mut self) -> Option<&mut CurrentAssignment<'db>> {
-        self.current_assignments.last_mut()
-    }
-
     fn add_pattern_constraint(
         &mut self,
         subject: &ast::Expr,
@@ -658,7 +682,7 @@ where
                         ast::Expr::List(_) | ast::Expr::Tuple(_) => {
                             Some(CurrentAssignment::Assign {
                                 node,
-                                first: true,
+
                                 unpack: Some(Unpack::new(
                                     self.db,
                                     self.file,
@@ -672,11 +696,9 @@ where
                                 )),
                             })
                         }
-                        ast::Expr::Name(_) => Some(CurrentAssignment::Assign {
-                            node,
-                            unpack: None,
-                            first: false,
-                        }),
+                        ast::Expr::Name(_) => {
+                            Some(CurrentAssignment::Assign { node, unpack: None })
+                        }
                         _ => None,
                     };
 
@@ -741,7 +763,22 @@ where
                 let mut constraints = vec![constraint];
                 self.visit_body(&node.body);
                 let mut post_clauses: Vec<FlowSnapshot> = vec![];
-                for clause in &node.elif_else_clauses {
+                let elif_else_clauses = node
+                    .elif_else_clauses
+                    .iter()
+                    .map(|clause| (clause.test.as_ref(), clause.body.as_slice()));
+                let has_else = node
+                    .elif_else_clauses
+                    .last()
+                    .is_some_and(|clause| clause.test.is_none());
+                let elif_else_clauses = elif_else_clauses.chain(if has_else {
+                    // if there's an `else` clause already, we don't need to add another
+                    None
+                } else {
+                    // if there's no `else` branch, we should add a no-op `else` branch
+                    Some((None, Default::default()))
+                });
+                for (clause_test, clause_body) in elif_else_clauses {
                     // snapshot after every block except the last; the last one will just become
                     // the state that we merge the other snapshots into
                     post_clauses.push(self.flow_snapshot());
@@ -751,24 +788,15 @@ where
                     for constraint in &constraints {
                         self.record_negated_constraint(*constraint);
                     }
-                    if let Some(elif_test) = &clause.test {
+                    if let Some(elif_test) = clause_test {
                         self.visit_expr(elif_test);
                         constraints.push(self.record_expression_constraint(elif_test));
                     }
-                    self.visit_body(&clause.body);
+                    self.visit_body(clause_body);
                 }
                 for post_clause_state in post_clauses {
                     self.flow_merge(post_clause_state);
                 }
-                let has_else = node
-                    .elif_else_clauses
-                    .last()
-                    .is_some_and(|clause| clause.test.is_none());
-                if !has_else {
-                    // if there's no else clause, then it's possible we took none of the branches,
-                    // and the pre_if state can reach here
-                    self.flow_merge(pre_if);
-                }
             }
             ast::Stmt::While(ast::StmtWhile {
                 test,
@@ -785,7 +813,10 @@ where
 
                 // TODO: definitions created inside the body should be fully visible
                 // to other statements/expressions inside the body --Alex/Carl
+                let outer_loop_state = self.loop_state();
+                self.set_inside_loop(LoopState::InLoop);
                 self.visit_body(body);
+                self.set_inside_loop(outer_loop_state);
 
                 // Get the break states from the body of this loop, and restore the saved outer
                 // ones.
@@ -824,7 +855,9 @@ where
                 self.visit_body(body);
             }
             ast::Stmt::Break(_) => {
-                self.loop_break_states.push(self.flow_snapshot());
+                if self.loop_state().is_inside() {
+                    self.loop_break_states.push(self.flow_snapshot());
+                }
             }
 
             ast::Stmt::For(
@@ -851,7 +884,10 @@ where
                 // TODO: Definitions created by loop variables
                 // (and definitions created inside the body)
                 // are fully visible to other statements/expressions inside the body --Alex/Carl
+                let outer_loop_state = self.loop_state();
+                self.set_inside_loop(LoopState::InLoop);
                 self.visit_body(body);
+                self.set_inside_loop(outer_loop_state);
 
                 let break_states =
                     std::mem::replace(&mut self.loop_break_states, saved_break_states);
@@ -1040,18 +1076,13 @@ where
 
                 if is_definition {
                     match self.current_assignment() {
-                        Some(CurrentAssignment::Assign {
-                            node,
-                            first,
-                            unpack,
-                        }) => {
+                        Some(CurrentAssignment::Assign { node, unpack }) => {
                             self.add_definition(
                                 symbol,
                                 AssignmentDefinitionNodeRef {
                                     unpack,
                                     value: &node.value,
                                     name: name_node,
-                                    first,
                                 },
                             );
                         }
@@ -1102,11 +1133,6 @@ where
                     }
                 }
 
-                if let Some(CurrentAssignment::Assign { first, .. }) = self.current_assignment_mut()
-                {
-                    *first = false;
-                }
-
                 walk_expr(self, expr);
             }
             ast::Expr::Named(node) => {
@@ -1153,8 +1179,8 @@ where
                 // AST inspection, so we can't simplify here, need to record test expression for
                 // later checking)
                 self.visit_expr(test);
-                let constraint = self.record_expression_constraint(test);
                 let pre_if = self.flow_snapshot();
+                let constraint = self.record_expression_constraint(test);
                 self.visit_expr(body);
                 let post_body = self.flow_snapshot();
                 self.flow_restore(pre_if);
@@ -1313,7 +1339,6 @@ where
 enum CurrentAssignment<'a> {
     Assign {
         node: &'a ast::StmtAssign,
-        first: bool,
         unpack: Option<Unpack<'a>>,
     },
     AnnAssign(&'a ast::StmtAnnAssign),

crates/red_knot_python_semantic/src/semantic_index/definition.rs

@@ -211,7 +211,6 @@ pub(crate) struct AssignmentDefinitionNodeRef<'a> {
     pub(crate) unpack: Option<Unpack<'a>>,
     pub(crate) value: &'a ast::Expr,
     pub(crate) name: &'a ast::ExprName,
-    pub(crate) first: bool,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -282,12 +281,10 @@ impl<'db> DefinitionNodeRef<'db> {
                 unpack,
                 value,
                 name,
-                first,
             }) => DefinitionKind::Assignment(AssignmentDefinitionKind {
                 target: TargetKind::from(unpack),
                 value: AstNodeRef::new(parsed.clone(), value),
                 name: AstNodeRef::new(parsed, name),
-                first,
             }),
             DefinitionNodeRef::AnnotatedAssignment(assign) => {
                 DefinitionKind::AnnotatedAssignment(AstNodeRef::new(parsed, assign))
@@ -374,7 +371,6 @@ impl<'db> DefinitionNodeRef<'db> {
                 value: _,
                 unpack: _,
                 name,
-                first: _,
             }) => name.into(),
             Self::AnnotatedAssignment(node) => node.into(),
             Self::AugmentedAssignment(node) => node.into(),
@@ -591,7 +587,6 @@ pub struct AssignmentDefinitionKind<'db> {
     target: TargetKind<'db>,
     value: AstNodeRef<ast::Expr>,
     name: AstNodeRef<ast::ExprName>,
-    first: bool,
 }
 
 impl<'db> AssignmentDefinitionKind<'db> {
@@ -606,10 +601,6 @@ impl<'db> AssignmentDefinitionKind<'db> {
     pub(crate) fn name(&self) -> &ast::ExprName {
         self.name.node()
     }
-
-    pub(crate) fn is_first(&self) -> bool {
-        self.first
-    }
 }
 
 #[derive(Clone, Debug)]

crates/red_knot_python_semantic/src/semantic_index/use_def.rs

@@ -400,7 +400,7 @@ pub(crate) struct ConstraintsIterator<'map, 'db> {
     constraint_ids: ConstraintIdIterator<'map>,
 }
 
-impl<'map, 'db> Iterator for ConstraintsIterator<'map, 'db> {
+impl<'db> Iterator for ConstraintsIterator<'_, 'db> {
     type Item = Constraint<'db>;
 
     fn next(&mut self) -> Option<Self::Item> {
@@ -424,7 +424,7 @@ impl DeclarationsIterator<'_, '_> {
     }
 }
 
-impl<'map, 'db> Iterator for DeclarationsIterator<'map, 'db> {
+impl<'db> Iterator for DeclarationsIterator<'_, 'db> {
     type Item = Definition<'db>;
 
     fn next(&mut self) -> Option<Self::Item> {

crates/red_knot_python_semantic/src/semantic_index/use_def/symbol_state.rs

@@ -401,7 +401,7 @@ pub(super) struct DeclarationIdIterator<'a> {
     inner: DeclarationsIterator<'a>,
 }
 
-impl<'a> Iterator for DeclarationIdIterator<'a> {
+impl Iterator for DeclarationIdIterator<'_> {
     type Item = ScopedDefinitionId;
 
     fn next(&mut self) -> Option<Self::Item> {

crates/red_knot_python_semantic/src/types.rs

@@ -7,7 +7,6 @@ use ruff_db::files::File;
 use ruff_python_ast as ast;
 
 pub(crate) use self::builder::{IntersectionBuilder, UnionBuilder};
-pub use self::diagnostic::{TypeCheckDiagnostic, TypeCheckDiagnostics};
 pub(crate) use self::display::TypeArrayDisplay;
 pub(crate) use self::infer::{
     infer_deferred_types, infer_definition_types, infer_expression_types, infer_scope_types,
@@ -25,7 +24,9 @@ use crate::stdlib::{
     builtins_symbol, core_module_symbol, typing_extensions_symbol, CoreStdlibModule,
 };
 use crate::symbol::{Boundness, Symbol};
-use crate::types::diagnostic::TypeCheckDiagnosticsBuilder;
+use crate::types::diagnostic::{
+    report_not_iterable, report_not_iterable_possibly_unbound, report_type_diagnostic,
+};
 use crate::types::mro::{ClassBase, Mro, MroError, MroIterator};
 use crate::types::narrow::narrowing_constraint;
 use crate::{Db, FxOrderSet, Module, Program};
@@ -40,21 +41,20 @@ mod signatures;
 mod string_annotation;
 mod unpacker;
 
-#[salsa::tracked(return_ref)]
-pub fn check_types(db: &dyn Db, file: File) -> TypeCheckDiagnostics {
+#[cfg(test)]
+mod property_tests;
+
+#[salsa::tracked]
+pub fn check_types(db: &dyn Db, file: File) {
     let _span = tracing::trace_span!("check_types", file=?file.path(db)).entered();
 
     tracing::debug!("Checking file '{path}'", path = file.path(db));
 
     let index = semantic_index(db, file);
-    let mut diagnostics = TypeCheckDiagnostics::default();
 
     for scope_id in index.scope_ids() {
-        let result = infer_scope_types(db, scope_id);
-        diagnostics.extend(result.diagnostics());
+        let _ = infer_scope_types(db, scope_id);
     }
-
-    diagnostics
 }
 
 /// Infer the public type of a symbol (its type as seen from outside its scope).
@@ -537,6 +537,19 @@ impl<'db> Type<'db> {
             .expect("Expected a Type::IntLiteral variant")
     }
 
+    pub const fn into_known_instance(self) -> Option<KnownInstanceType<'db>> {
+        match self {
+            Type::KnownInstance(known_instance) => Some(known_instance),
+            _ => None,
+        }
+    }
+
+    #[track_caller]
+    pub fn expect_known_instance(self) -> KnownInstanceType<'db> {
+        self.into_known_instance()
+            .expect("Expected a Type::KnownInstance variant")
+    }
+
     pub const fn is_boolean_literal(&self) -> bool {
         matches!(self, Type::BooleanLiteral(..))
     }
@@ -561,8 +574,11 @@ impl<'db> Type<'db> {
         Self::BytesLiteral(BytesLiteralType::new(db, bytes))
     }
 
-    pub fn tuple(db: &'db dyn Db, elements: &[Type<'db>]) -> Self {
-        Self::Tuple(TupleType::new(db, elements))
+    pub fn tuple<T: Into<Type<'db>>>(
+        db: &'db dyn Db,
+        elements: impl IntoIterator<Item = T>,
+    ) -> Self {
+        TupleType::from_elements(db, elements)
     }
 
     #[must_use]
@@ -706,9 +722,6 @@ impl<'db> Type<'db> {
             (Type::KnownInstance(left), right) => {
                 left.instance_fallback(db).is_subtype_of(db, right)
             }
-            (left, Type::KnownInstance(right)) => {
-                left.is_subtype_of(db, right.instance_fallback(db))
-            }
             (Type::Instance(left), Type::Instance(right)) => left.is_instance_of(db, right.class),
             // TODO
             _ => false,
@@ -1390,7 +1403,7 @@ impl<'db> Type<'db> {
             // `Any` is callable, and its return type is also `Any`.
             Type::Any => CallOutcome::callable(Type::Any),
 
-            Type::Todo(_) => CallOutcome::callable(todo_type!()),
+            Type::Todo(_) => CallOutcome::callable(todo_type!("call todo")),
 
             Type::Unknown => CallOutcome::callable(Type::Unknown),
 
@@ -1540,6 +1553,10 @@ impl<'db> Type<'db> {
             // TODO map this to a new `Type::TypeVar` variant
             Type::KnownInstance(KnownInstanceType::TypeVar(_)) => *self,
             Type::KnownInstance(KnownInstanceType::TypeAliasType(alias)) => alias.value_ty(db),
+            Type::KnownInstance(KnownInstanceType::Never | KnownInstanceType::NoReturn) => {
+                Type::Never
+            }
+            Type::KnownInstance(KnownInstanceType::LiteralString) => Type::LiteralString,
             _ => todo_type!(),
         }
     }
@@ -1872,10 +1889,16 @@ impl<'db> KnownClass {
 pub enum KnownInstanceType<'db> {
     /// The symbol `typing.Literal` (which can also be found as `typing_extensions.Literal`)
     Literal,
+    /// The symbol `typing.LiteralString` (which can also be found as `typing_extensions.LiteralString`)
+    LiteralString,
     /// The symbol `typing.Optional` (which can also be found as `typing_extensions.Optional`)
     Optional,
     /// The symbol `typing.Union` (which can also be found as `typing_extensions.Union`)
     Union,
+    /// The symbol `typing.NoReturn` (which can also be found as `typing_extensions.NoReturn`)
+    NoReturn,
+    /// The symbol `typing.Never` available since 3.11 (which can also be found as `typing_extensions.Never`)
+    Never,
     /// A single instance of `typing.TypeVar`
     TypeVar(TypeVarInstance<'db>),
     /// A single instance of `typing.TypeAliasType` (PEP 695 type alias)
@@ -1886,11 +1909,14 @@ pub enum KnownInstanceType<'db> {
 impl<'db> KnownInstanceType<'db> {
     pub const fn as_str(self) -> &'static str {
         match self {
-            KnownInstanceType::Literal => "Literal",
-            KnownInstanceType::Optional => "Optional",
-            KnownInstanceType::Union => "Union",
-            KnownInstanceType::TypeVar(_) => "TypeVar",
-            KnownInstanceType::TypeAliasType(_) => "TypeAliasType",
+            Self::Literal => "Literal",
+            Self::LiteralString => "LiteralString",
+            Self::Optional => "Optional",
+            Self::Union => "Union",
+            Self::TypeVar(_) => "TypeVar",
+            Self::NoReturn => "NoReturn",
+            Self::Never => "Never",
+            Self::TypeAliasType(_) => "TypeAliasType",
         }
     }
 
@@ -1898,9 +1924,12 @@ impl<'db> KnownInstanceType<'db> {
     pub const fn bool(self) -> Truthiness {
         match self {
             Self::Literal
+            | Self::LiteralString
             | Self::Optional
             | Self::TypeVar(_)
             | Self::Union
+            | Self::NoReturn
+            | Self::Never
             | Self::TypeAliasType(_) => Truthiness::AlwaysTrue,
         }
     }
@@ -1909,8 +1938,11 @@ impl<'db> KnownInstanceType<'db> {
     pub fn repr(self, db: &'db dyn Db) -> &'db str {
         match self {
             Self::Literal => "typing.Literal",
+            Self::LiteralString => "typing.LiteralString",
             Self::Optional => "typing.Optional",
             Self::Union => "typing.Union",
+            Self::NoReturn => "typing.NoReturn",
+            Self::Never => "typing.Never",
             Self::TypeVar(typevar) => typevar.name(db),
             Self::TypeAliasType(_) => "typing.TypeAliasType",
         }
@@ -1920,8 +1952,11 @@ impl<'db> KnownInstanceType<'db> {
     pub const fn class(self) -> KnownClass {
         match self {
             Self::Literal => KnownClass::SpecialForm,
+            Self::LiteralString => KnownClass::SpecialForm,
             Self::Optional => KnownClass::SpecialForm,
             Self::Union => KnownClass::SpecialForm,
+            Self::NoReturn => KnownClass::SpecialForm,
+            Self::Never => KnownClass::SpecialForm,
             Self::TypeVar(_) => KnownClass::TypeVar,
             Self::TypeAliasType(_) => KnownClass::TypeAliasType,
         }
@@ -1942,8 +1977,11 @@ impl<'db> KnownInstanceType<'db> {
         }
         match (module.name().as_str(), instance_name) {
             ("typing" | "typing_extensions", "Literal") => Some(Self::Literal),
+            ("typing" | "typing_extensions", "LiteralString") => Some(Self::LiteralString),
             ("typing" | "typing_extensions", "Optional") => Some(Self::Optional),
             ("typing" | "typing_extensions", "Union") => Some(Self::Union),
+            ("typing" | "typing_extensions", "NoReturn") => Some(Self::NoReturn),
+            ("typing" | "typing_extensions", "Never") => Some(Self::Never),
             _ => None,
         }
     }
@@ -1951,23 +1989,6 @@ impl<'db> KnownInstanceType<'db> {
     fn member(self, db: &'db dyn Db, name: &str) -> Symbol<'db> {
         let ty = match (self, name) {
             (Self::TypeVar(typevar), "__name__") => Type::string_literal(db, typevar.name(db)),
-            (Self::TypeVar(typevar), "__bound__") => typevar
-                .upper_bound(db)
-                .map(|ty| ty.to_meta_type(db))
-                .unwrap_or_else(|| KnownClass::NoneType.to_instance(db)),
-            (Self::TypeVar(typevar), "__constraints__") => {
-                let tuple_elements: Vec<Type<'db>> = typevar
-                    .constraints(db)
-                    .unwrap_or_default()
-                    .iter()
-                    .map(|ty| ty.to_meta_type(db))
-                    .collect();
-                Type::tuple(db, &tuple_elements)
-            }
-            (Self::TypeVar(typevar), "__default__") => typevar
-                .default_ty(db)
-                .map(|ty| ty.to_meta_type(db))
-                .unwrap_or_else(|| KnownClass::NoDefaultType.to_instance(db)),
             (Self::TypeAliasType(alias), "__name__") => Type::string_literal(db, alias.name(db)),
             _ => return self.instance_fallback(db).member(db, name),
         };
@@ -2000,6 +2021,7 @@ pub struct TypeVarInstance<'db> {
 }
 
 impl<'db> TypeVarInstance<'db> {
+    #[allow(unused)]
     pub(crate) fn upper_bound(self, db: &'db dyn Db) -> Option<Type<'db>> {
         if let Some(TypeVarBoundOrConstraints::UpperBound(ty)) = self.bound_or_constraints(db) {
             Some(ty)
@@ -2008,7 +2030,8 @@ impl<'db> TypeVarInstance<'db> {
         }
     }
 
-    pub(crate) fn constraints(self, db: &'db dyn Db) -> Option<&[Type<'db>]> {
+    #[allow(unused)]
+    pub(crate) fn constraints(self, db: &'db dyn Db) -> Option<&'db [Type<'db>]> {
         if let Some(TypeVarBoundOrConstraints::Constraints(tuple)) = self.bound_or_constraints(db) {
             Some(tuple.elements(db))
         } else {
@@ -2105,19 +2128,21 @@ impl<'db> CallOutcome<'db> {
     }
 
     /// Get the return type of the call, emitting default diagnostics if needed.
-    fn unwrap_with_diagnostic<'a>(
+    fn unwrap_with_diagnostic(
         &self,
         db: &'db dyn Db,
+        file: File,
         node: ast::AnyNodeRef,
-        diagnostics: &'a mut TypeCheckDiagnosticsBuilder<'db>,
     ) -> Type<'db> {
-        match self.return_ty_result(db, node, diagnostics) {
+        match self.return_ty_result(db, file, node) {
             Ok(return_ty) => return_ty,
             Err(NotCallableError::Type {
                 not_callable_ty,
                 return_ty,
             }) => {
-                diagnostics.add(
+                report_type_diagnostic(
+                    db,
+                    file,
                     node,
                     "call-non-callable",
                     format_args!(
@@ -2132,7 +2157,9 @@ impl<'db> CallOutcome<'db> {
                 called_ty,
                 return_ty,
             }) => {
-                diagnostics.add(
+                report_type_diagnostic(
+                    db,
+                    file,
                     node,
                     "call-non-callable",
                     format_args!(
@@ -2148,7 +2175,9 @@ impl<'db> CallOutcome<'db> {
                 called_ty,
                 return_ty,
             }) => {
-                diagnostics.add(
+                report_type_diagnostic(
+                    db,
+                    file,
                     node,
                     "call-non-callable",
                     format_args!(
@@ -2163,7 +2192,9 @@ impl<'db> CallOutcome<'db> {
                 callable_ty: called_ty,
                 return_ty,
             }) => {
-                diagnostics.add(
+                report_type_diagnostic(
+                    db,
+                    file,
                     node,
                     "call-non-callable",
                     format_args!(
@@ -2177,11 +2208,11 @@ impl<'db> CallOutcome<'db> {
     }
 
     /// Get the return type of the call as a result.
-    fn return_ty_result<'a>(
+    fn return_ty_result(
         &self,
         db: &'db dyn Db,
+        file: File,
         node: ast::AnyNodeRef,
-        diagnostics: &'a mut TypeCheckDiagnosticsBuilder<'db>,
     ) -> Result<Type<'db>, NotCallableError<'db>> {
         match self {
             Self::Callable { return_ty } => Ok(*return_ty),
@@ -2189,7 +2220,9 @@ impl<'db> CallOutcome<'db> {
                 return_ty,
                 revealed_ty,
             } => {
-                diagnostics.add(
+                report_type_diagnostic(
+                    db,
+                    file,
                     node,
                     "revealed-type",
                     format_args!("Revealed type is `{}`", revealed_ty.display(db)),
@@ -2228,10 +2261,10 @@ impl<'db> CallOutcome<'db> {
                                 *return_ty
                             } else {
                                 revealed = true;
-                                outcome.unwrap_with_diagnostic(db, node, diagnostics)
+                                outcome.unwrap_with_diagnostic(db, file, node)
                             }
                         }
-                        _ => outcome.unwrap_with_diagnostic(db, node, diagnostics),
+                        _ => outcome.unwrap_with_diagnostic(db, file, node),
                     };
                     union_builder = union_builder.add(return_ty);
                 }
@@ -2346,20 +2379,21 @@ enum IterationOutcome<'db> {
 impl<'db> IterationOutcome<'db> {
     fn unwrap_with_diagnostic(
         self,
+        db: &dyn Db,
+        file: File,
         iterable_node: ast::AnyNodeRef,
-        diagnostics: &mut TypeCheckDiagnosticsBuilder<'db>,
     ) -> Type<'db> {
         match self {
             Self::Iterable { element_ty } => element_ty,
             Self::NotIterable { not_iterable_ty } => {
-                diagnostics.add_not_iterable(iterable_node, not_iterable_ty);
+                report_not_iterable(db, file, iterable_node, not_iterable_ty);
                 Type::Unknown
             }
             Self::PossiblyUnboundDunderIter {
                 iterable_ty,
                 element_ty,
             } => {
-                diagnostics.add_not_iterable_possibly_unbound(iterable_node, iterable_ty);
+                report_not_iterable_possibly_unbound(db, file, iterable_node, iterable_ty);
                 element_ty
             }
         }
@@ -2552,7 +2586,7 @@ impl<'db> Class<'db> {
     ///
     /// Were this not a salsa query, then the calling query
     /// would depend on the class's AST and rerun for every change in that file.
-    fn explicit_bases(self, db: &'db dyn Db) -> &[Type<'db>] {
+    fn explicit_bases(self, db: &'db dyn Db) -> &'db [Type<'db>] {
         self.explicit_bases_query(db)
     }
 
@@ -2980,7 +3014,7 @@ pub struct SliceLiteralType<'db> {
     step: Option<i32>,
 }
 
-impl<'db> SliceLiteralType<'db> {
+impl SliceLiteralType<'_> {
     fn as_tuple(self, db: &dyn Db) -> (Option<i32>, Option<i32>, Option<i32>) {
         (self.start(db), self.stop(db), self.step(db))
     }
@@ -2992,6 +3026,23 @@ pub struct TupleType<'db> {
 }
 
 impl<'db> TupleType<'db> {
+    pub fn from_elements<T: Into<Type<'db>>>(
+        db: &'db dyn Db,
+        types: impl IntoIterator<Item = T>,
+    ) -> Type<'db> {
+        let mut elements = vec![];
+
+        for ty in types {
+            let ty = ty.into();
+            if ty.is_never() {
+                return Type::Never;
+            }
+            elements.push(ty);
+        }
+
+        Type::Tuple(Self::new(db, elements.into_boxed_slice()))
+    }
+
     pub fn get(&self, db: &'db dyn Db, index: usize) -> Option<Type<'db>> {
         self.elements(db).get(index).copied()
     }
@@ -3043,8 +3094,8 @@ pub(crate) mod tests {
 
     /// A test representation of a type that can be transformed unambiguously into a real Type,
     /// given a db.
-    #[derive(Debug, Clone)]
-    enum Ty {
+    #[derive(Debug, Clone, PartialEq)]
+    pub(crate) enum Ty {
         Never,
         Unknown,
         None,
@@ -3068,7 +3119,7 @@ pub(crate) mod tests {
     }
 
     impl Ty {
-        fn into_type(self, db: &TestDb) -> Type<'_> {
+        pub(crate) fn into_type(self, db: &TestDb) -> Type<'_> {
             match self {
                 Ty::Never => Type::Never,
                 Ty::Unknown => Type::Unknown,
@@ -3099,13 +3150,21 @@ pub(crate) mod tests {
                     builder.build()
                 }
                 Ty::Tuple(tys) => {
-                    let elements: Vec<Type> = tys.into_iter().map(|ty| ty.into_type(db)).collect();
-                    Type::tuple(db, &elements)
+                    let elements = tys.into_iter().map(|ty| ty.into_type(db));
+                    Type::tuple(db, elements)
                 }
             }
         }
     }
 
+    #[test_case(Ty::Tuple(vec![Ty::Never]))]
+    #[test_case(Ty::Tuple(vec![Ty::BuiltinInstance("str"), Ty::Never, Ty::BuiltinInstance("int")]))]
+    #[test_case(Ty::Tuple(vec![Ty::Tuple(vec![Ty::Never])]))]
+    fn tuple_containing_never_simplifies_to_never(ty: Ty) {
+        let db = setup_db();
+        assert_eq!(ty.into_type(&db), Type::Never);
+    }
+
     #[test_case(Ty::BuiltinInstance("str"), Ty::BuiltinInstance("object"))]
     #[test_case(Ty::BuiltinInstance("int"), Ty::BuiltinInstance("object"))]
     #[test_case(Ty::Unknown, Ty::IntLiteral(1))]
@@ -3219,6 +3278,7 @@ pub(crate) mod tests {
     #[test_case(Ty::IntLiteral(1), Ty::Intersection{pos: vec![Ty::BuiltinInstance("int")], neg: vec![Ty::IntLiteral(1)]})]
     #[test_case(Ty::BuiltinClassLiteral("int"), Ty::BuiltinClassLiteral("object"))]
     #[test_case(Ty::BuiltinInstance("int"), Ty::BuiltinClassLiteral("int"))]
+    #[test_case(Ty::TypingInstance("_SpecialForm"), Ty::TypingLiteral)]
     fn is_not_subtype_of(from: Ty, to: Ty) {
         let db = setup_db();
         assert!(!from.into_type(&db).is_subtype_of(&db, to.into_type(&db)));

crates/red_knot_python_semantic/src/types/diagnostic.rs

@@ -1,16 +1,12 @@
 use crate::types::{ClassLiteralType, Type};
 use crate::Db;
-use ruff_db::diagnostic::{Diagnostic, Severity};
+use ruff_db::diagnostic::{CompileDiagnostic, Diagnostic, Severity};
 use ruff_db::files::File;
 use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_text_size::{Ranged, TextRange};
 use std::borrow::Cow;
-use std::fmt::Formatter;
-use std::ops::Deref;
-use std::sync::Arc;
-
 #[derive(Debug, Eq, PartialEq, Clone)]
-pub struct TypeCheckDiagnostic {
+pub(crate) struct TypeCheckDiagnostic {
     // TODO: Don't use string keys for rules
     pub(super) rule: String,
     pub(super) message: String,
@@ -19,15 +15,15 @@ pub struct TypeCheckDiagnostic {
 }
 
 impl TypeCheckDiagnostic {
-    pub fn rule(&self) -> &str {
+    pub(crate) fn rule(&self) -> &str {
         &self.rule
     }
 
-    pub fn message(&self) -> &str {
+    pub(crate) fn message(&self) -> &str {
         &self.message
     }
 
-    pub fn file(&self) -> File {
+    pub(crate) fn file(&self) -> File {
         self.file
     }
 }
@@ -60,263 +56,209 @@ impl Ranged for TypeCheckDiagnostic {
     }
 }
 
-/// 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(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()
-    }
-}
-
-pub(super) struct TypeCheckDiagnosticsBuilder<'db> {
-    db: &'db dyn Db,
+/// Emit a diagnostic declaring that the object represented by `node` is not iterable
+pub(super) fn report_not_iterable(
+    db: &dyn Db,
     file: File,
-    diagnostics: TypeCheckDiagnostics,
+    node: AnyNodeRef,
+    not_iterable_ty: Type,
+) {
+    report_type_diagnostic(
+        db,
+        file,
+        node,
+        "not-iterable",
+        format_args!(
+            "Object of type `{}` is not iterable",
+            not_iterable_ty.display(db)
+        ),
+    );
 }
 
-impl<'db> TypeCheckDiagnosticsBuilder<'db> {
-    pub(super) fn new(db: &'db dyn Db, file: File) -> Self {
-        Self {
-            db,
+/// Emit a diagnostic declaring that the object represented by `node` is not iterable
+/// because its `__iter__` method is possibly unbound.
+pub(super) fn report_not_iterable_possibly_unbound(
+    db: &dyn Db,
+    file: File,
+    node: AnyNodeRef,
+    element_ty: Type,
+) {
+    report_type_diagnostic(
+        db,
+        file,
+        node,
+        "not-iterable",
+        format_args!(
+            "Object of type `{}` is not iterable because its `__iter__` method is possibly unbound",
+            element_ty.display(db)
+        ),
+    );
+}
+
+/// Emit a diagnostic declaring that an index is out of bounds for a tuple.
+pub(super) fn report_index_out_of_bounds(
+    db: &dyn Db,
+    file: File,
+    kind: &'static str,
+    node: AnyNodeRef,
+    tuple_ty: Type,
+    length: usize,
+    index: i64,
+) {
+    report_type_diagnostic(
+        db,
+        file,
+        node,
+        "index-out-of-bounds",
+        format_args!(
+            "Index {index} is out of bounds for {kind} `{}` with length {length}",
+            tuple_ty.display(db)
+        ),
+    );
+}
+
+/// Emit a diagnostic declaring that a type does not support subscripting.
+pub(super) fn report_non_subscriptable(
+    db: &dyn Db,
+    file: File,
+    node: AnyNodeRef,
+    non_subscriptable_ty: Type,
+    method: &str,
+) {
+    report_type_diagnostic(
+        db,
+        file,
+        node,
+        "non-subscriptable",
+        format_args!(
+            "Cannot subscript object of type `{}` with no `{method}` method",
+            non_subscriptable_ty.display(db)
+        ),
+    );
+}
+
+pub(super) fn report_unresolved_module<'a>(
+    db: &dyn Db,
+    file: File,
+    import_node: impl Into<AnyNodeRef<'a>>,
+    level: u32,
+    module: Option<&str>,
+) {
+    report_type_diagnostic(
+        db,
+        file,
+        import_node.into(),
+        "unresolved-import",
+        format_args!(
+            "Cannot resolve import `{}{}`",
+            ".".repeat(level as usize),
+            module.unwrap_or_default()
+        ),
+    );
+}
+
+pub(super) fn report_slice_step_size_zero(db: &dyn Db, file: File, node: AnyNodeRef) {
+    report_type_diagnostic(
+        db,
+        file,
+        node,
+        "zero-stepsize-in-slice",
+        format_args!("Slice step size can not be zero"),
+    );
+}
+
+pub(super) fn report_invalid_assignment(
+    db: &dyn Db,
+    file: File,
+    node: AnyNodeRef,
+    declared_ty: Type,
+    assigned_ty: Type,
+) {
+    match declared_ty {
+        Type::ClassLiteral(ClassLiteralType { class }) => {
+            report_type_diagnostic(db, file, node, "invalid-assignment", format_args!(
+                "Implicit shadowing of class `{}`; annotate to make it explicit if this is intentional",
+                class.name(db)));
+        }
+        Type::FunctionLiteral(function) => {
+            report_type_diagnostic(db, file, node, "invalid-assignment", format_args!(
+                "Implicit shadowing of function `{}`; annotate to make it explicit if this is intentional",
+                function.name(db)));
+        }
+        _ => {
+            report_type_diagnostic(
+                db,
+                file,
+                node,
+                "invalid-assignment",
+                format_args!(
+                    "Object of type `{}` is not assignable to `{}`",
+                    assigned_ty.display(db),
+                    declared_ty.display(db),
+                ),
+            );
+        }
+    }
+}
+
+pub(super) fn report_possibly_unresolved_reference(
+    db: &dyn Db,
+    file: File,
+    expr_name_node: &ast::ExprName,
+) {
+    let ast::ExprName { id, .. } = expr_name_node;
+
+    report_type_diagnostic(
+        db,
+        file,
+        expr_name_node.into(),
+        "possibly-unresolved-reference",
+        format_args!("Name `{id}` used when possibly not defined"),
+    );
+}
+
+pub(super) fn report_unresolved_reference(db: &dyn Db, file: File, expr_name_node: &ast::ExprName) {
+    let ast::ExprName { id, .. } = expr_name_node;
+
+    report_type_diagnostic(
+        db,
+        file,
+        expr_name_node.into(),
+        "unresolved-reference",
+        format_args!("Name `{id}` used when not defined"),
+    );
+}
+
+/// Returns `true` if any diagnostic is enabled for this file.
+pub(crate) fn is_any_diagnostic_enabled(db: &dyn Db, file: File) -> bool {
+    db.is_file_open(file)
+}
+
+/// Reports a diagnostic for the given node and file if diagnostic reporting is enabled for this file.
+pub(crate) fn report_type_diagnostic(
+    db: &dyn Db,
+    file: File,
+    node: AnyNodeRef,
+    rule: &str,
+    message: std::fmt::Arguments,
+) {
+    if !is_any_diagnostic_enabled(db, 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.
+
+    CompileDiagnostic::report(
+        db.upcast(),
+        TypeCheckDiagnostic {
             file,
-            diagnostics: TypeCheckDiagnostics::default(),
-        }
-    }
-
-    /// Emit a diagnostic declaring that the object represented by `node` is not iterable
-    pub(super) fn add_not_iterable(&mut self, node: AnyNodeRef, not_iterable_ty: Type<'db>) {
-        self.add(
-            node,
-            "not-iterable",
-            format_args!(
-                "Object of type `{}` is not iterable",
-                not_iterable_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that the object represented by `node` is not iterable
-    /// because its `__iter__` method is possibly unbound.
-    pub(super) fn add_not_iterable_possibly_unbound(
-        &mut self,
-        node: AnyNodeRef,
-        element_ty: Type<'db>,
-    ) {
-        self.add(
-            node,
-            "not-iterable",
-            format_args!(
-                "Object of type `{}` is not iterable because its `__iter__` method is possibly unbound",
-                element_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that an index is out of bounds for a tuple.
-    pub(super) fn add_index_out_of_bounds(
-        &mut self,
-        kind: &'static str,
-        node: AnyNodeRef,
-        tuple_ty: Type<'db>,
-        length: usize,
-        index: i64,
-    ) {
-        self.add(
-            node,
-            "index-out-of-bounds",
-            format_args!(
-                "Index {index} is out of bounds for {kind} `{}` with length {length}",
-                tuple_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that a type does not support subscripting.
-    pub(super) fn add_non_subscriptable(
-        &mut self,
-        node: AnyNodeRef,
-        non_subscriptable_ty: Type<'db>,
-        method: &str,
-    ) {
-        self.add(
-            node,
-            "non-subscriptable",
-            format_args!(
-                "Cannot subscript object of type `{}` with no `{method}` method",
-                non_subscriptable_ty.display(self.db)
-            ),
-        );
-    }
-
-    pub(super) fn add_unresolved_module(
-        &mut self,
-        import_node: impl Into<AnyNodeRef<'db>>,
-        level: u32,
-        module: Option<&str>,
-    ) {
-        self.add(
-            import_node.into(),
-            "unresolved-import",
-            format_args!(
-                "Cannot resolve import `{}{}`",
-                ".".repeat(level as usize),
-                module.unwrap_or_default()
-            ),
-        );
-    }
-
-    pub(super) fn add_slice_step_size_zero(&mut self, node: AnyNodeRef) {
-        self.add(
-            node,
-            "zero-stepsize-in-slice",
-            format_args!("Slice step size can not be zero"),
-        );
-    }
-
-    pub(super) fn add_invalid_assignment(
-        &mut self,
-        node: AnyNodeRef,
-        declared_ty: Type<'db>,
-        assigned_ty: Type<'db>,
-    ) {
-        match declared_ty {
-            Type::ClassLiteral(ClassLiteralType { class }) => {
-                self.add(node, "invalid-assignment", format_args!(
-                        "Implicit shadowing of class `{}`; annotate to make it explicit if this is intentional",
-                        class.name(self.db)));
-            }
-            Type::FunctionLiteral(function) => {
-                self.add(node, "invalid-assignment", format_args!(
-                        "Implicit shadowing of function `{}`; annotate to make it explicit if this is intentional",
-                        function.name(self.db)));
-            }
-            _ => {
-                self.add(
-                    node,
-                    "invalid-assignment",
-                    format_args!(
-                        "Object of type `{}` is not assignable to `{}`",
-                        assigned_ty.display(self.db),
-                        declared_ty.display(self.db),
-                    ),
-                );
-            }
-        }
-    }
-
-    pub(super) fn add_possibly_unresolved_reference(&mut self, expr_name_node: &ast::ExprName) {
-        let ast::ExprName { id, .. } = expr_name_node;
-
-        self.add(
-            expr_name_node.into(),
-            "possibly-unresolved-reference",
-            format_args!("Name `{id}` used when possibly not defined"),
-        );
-    }
-
-    pub(super) fn add_unresolved_reference(&mut self, expr_name_node: &ast::ExprName) {
-        let ast::ExprName { id, .. } = expr_name_node;
-
-        self.add(
-            expr_name_node.into(),
-            "unresolved-reference",
-            format_args!("Name `{id}` used when not defined"),
-        );
-    }
-
-    /// Adds a new diagnostic.
-    ///
-    /// The diagnostic does not get added if the rule isn't enabled for this file.
-    pub(super) fn add(&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.diagnostics.push(TypeCheckDiagnostic {
-            file: self.file,
             rule: rule.to_string(),
             message: message.to_string(),
             range: node.range(),
-        });
-    }
-
-    pub(super) fn extend(&mut self, diagnostics: &TypeCheckDiagnostics) {
-        self.diagnostics.extend(diagnostics);
-    }
-
-    pub(super) fn finish(mut self) -> TypeCheckDiagnostics {
-        self.diagnostics.shrink_to_fit();
-        self.diagnostics
-    }
+        },
+    );
 }

crates/red_knot_python_semantic/src/types/display.rs

@@ -289,7 +289,7 @@ struct DisplayMaybeNegatedType<'db> {
     negated: bool,
 }
 
-impl<'db> Display for DisplayMaybeNegatedType<'db> {
+impl Display for DisplayMaybeNegatedType<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         if self.negated {
             f.write_str("~")?;
@@ -319,7 +319,7 @@ pub(crate) struct DisplayTypeArray<'b, 'db> {
     db: &'db dyn Db,
 }
 
-impl<'db> Display for DisplayTypeArray<'_, 'db> {
+impl Display for DisplayTypeArray<'_, '_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         f.join(", ")
             .entries(self.types.iter().map(|ty| ty.display(self.db)))

crates/red_knot_python_semantic/src/types/infer.rs

@@ -48,7 +48,11 @@ use crate::semantic_index::semantic_index;
 use crate::semantic_index::symbol::{NodeWithScopeKind, NodeWithScopeRef, ScopeId};
 use crate::semantic_index::SemanticIndex;
 use crate::stdlib::builtins_module_scope;
-use crate::types::diagnostic::{TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
+use crate::types::diagnostic::{
+    report_index_out_of_bounds, report_invalid_assignment, report_non_subscriptable,
+    report_possibly_unresolved_reference, report_slice_step_size_zero, report_type_diagnostic,
+    report_unresolved_module, report_unresolved_reference,
+};
 use crate::types::mro::MroErrorKind;
 use crate::types::unpacker::{UnpackResult, Unpacker};
 use crate::types::{
@@ -216,9 +220,6 @@ pub(crate) struct TypeInference<'db> {
     /// The definitions that are deferred.
     deferred: FxHashSet<Definition<'db>>,
 
-    /// The diagnostics for this region.
-    diagnostics: TypeCheckDiagnostics,
-
     /// The scope belong to this region.
     scope: ScopeId<'db>,
 }
@@ -230,7 +231,7 @@ impl<'db> TypeInference<'db> {
             bindings: FxHashMap::default(),
             declarations: FxHashMap::default(),
             deferred: FxHashSet::default(),
-            diagnostics: TypeCheckDiagnostics::default(),
+
             scope,
         }
     }
@@ -254,15 +255,10 @@ impl<'db> TypeInference<'db> {
         self.declarations[&definition]
     }
 
-    pub(crate) fn diagnostics(&self) -> &TypeCheckDiagnostics {
-        &self.diagnostics
-    }
-
     fn shrink_to_fit(&mut self) {
         self.expressions.shrink_to_fit();
         self.bindings.shrink_to_fit();
         self.declarations.shrink_to_fit();
-        self.diagnostics.shrink_to_fit();
         self.deferred.shrink_to_fit();
     }
 }
@@ -341,8 +337,6 @@ pub(super) struct TypeInferenceBuilder<'db> {
     /// expression could be deferred if the file has `from __future__ import annotations` import or
     /// is a stub file but we're still in a non-deferred region.
     deferred_state: DeferredExpressionState,
-
-    diagnostics: TypeCheckDiagnosticsBuilder<'db>,
 }
 
 impl<'db> TypeInferenceBuilder<'db> {
@@ -373,7 +367,6 @@ impl<'db> TypeInferenceBuilder<'db> {
             file,
             deferred_state: DeferredExpressionState::None,
             types: TypeInference::empty(scope),
-            diagnostics: TypeCheckDiagnosticsBuilder::new(db, file),
         }
     }
 
@@ -386,7 +379,6 @@ impl<'db> TypeInferenceBuilder<'db> {
             .extend(inference.declarations.iter());
         self.types.expressions.extend(inference.expressions.iter());
         self.types.deferred.extend(inference.deferred.iter());
-        self.diagnostics.extend(&inference.diagnostics);
     }
 
     fn scope(&self) -> ScopeId<'db> {
@@ -501,7 +493,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         for (class, class_node) in class_definitions {
             // (1) Check that the class does not have a cyclic definition
             if class.is_cyclically_defined(self.db) {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     class_node.into(),
                     "cyclic-class-def",
                     format_args!(
@@ -521,7 +515,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     MroErrorKind::DuplicateBases(duplicates) => {
                         let base_nodes = class_node.bases();
                         for (index, duplicate) in duplicates {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 (&base_nodes[*index]).into(),
                                 "duplicate-base",
                                 format_args!("Duplicate base class `{}`", duplicate.name(self.db)),
@@ -531,7 +527,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     MroErrorKind::InvalidBases(bases) => {
                         let base_nodes = class_node.bases();
                         for (index, base_ty) in bases {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 (&base_nodes[*index]).into(),
                                 "invalid-base",
                                 format_args!(
@@ -541,7 +539,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                             );
                         }
                     }
-                    MroErrorKind::UnresolvableMro { bases_list } => self.diagnostics.add(
+                    MroErrorKind::UnresolvableMro { bases_list } => report_type_diagnostic(
+                        self.db,
+                        self.file,
                         class_node.into(),
                         "inconsistent-mro",
                         format_args!(
@@ -571,7 +571,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     } => {
                         let node = class_node.into();
                         if *candidate1_is_base_class {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 node,
                                 "conflicting-metaclass",
                                 format_args!(
@@ -586,7 +588,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                                 )
                             );
                         } else {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 node,
                                 "conflicting-metaclass",
                                 format_args!(
@@ -732,7 +736,9 @@ impl<'db> TypeInferenceBuilder<'db> {
             _ => return,
         };
 
-        self.diagnostics.add(
+        report_type_diagnostic(
+            self.db,
+            self.file,
             expr.into(),
             "division-by-zero",
             format_args!(
@@ -757,7 +763,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                 // TODO point out the conflicting declarations in the diagnostic?
                 let symbol_table = self.index.symbol_table(binding.file_scope(self.db));
                 let symbol_name = symbol_table.symbol(binding.symbol(self.db)).name();
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     node,
                     "conflicting-declarations",
                     format_args!(
@@ -769,8 +777,7 @@ impl<'db> TypeInferenceBuilder<'db> {
             },
         );
         if !bound_ty.is_assignable_to(self.db, declared_ty) {
-            self.diagnostics
-                .add_invalid_assignment(node, declared_ty, bound_ty);
+            report_invalid_assignment(self.db, self.file, node, declared_ty, bound_ty);
             // allow declarations to override inference in case of invalid assignment
             bound_ty = declared_ty;
         };
@@ -787,7 +794,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         let ty = if inferred_ty.is_assignable_to(self.db, ty) {
             ty
         } else {
-            self.diagnostics.add(
+            report_type_diagnostic(
+                self.db,
+                self.file,
                 node,
                 "invalid-declaration",
                 format_args!(
@@ -813,8 +822,7 @@ impl<'db> TypeInferenceBuilder<'db> {
         let inferred_ty = if inferred_ty.is_assignable_to(self.db, declared_ty) {
             inferred_ty
         } else {
-            self.diagnostics
-                .add_invalid_assignment(node, declared_ty, inferred_ty);
+            report_invalid_assignment(self.db, self.file, node, declared_ty, inferred_ty);
             // if the assignment is invalid, fall back to assuming the annotation is correct
             declared_ty
         };
@@ -1297,7 +1305,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         // TODO: Make use of Protocols when we support it (the manager be assignable to `contextlib.AbstractContextManager`).
         match (enter, exit) {
             (Symbol::Unbound, Symbol::Unbound) => {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     context_expression.into(),
                     "invalid-context-manager",
                     format_args!(
@@ -1308,7 +1318,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                 Type::Unknown
             }
             (Symbol::Unbound, _) => {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     context_expression.into(),
                     "invalid-context-manager",
                     format_args!(
@@ -1320,7 +1332,9 @@ impl<'db> TypeInferenceBuilder<'db> {
             }
             (Symbol::Type(enter_ty, enter_boundness), exit) => {
                 if enter_boundness == Boundness::PossiblyUnbound {
-                    self.diagnostics.add(
+                    report_type_diagnostic(
+                        self.db,
+                        self.file,
                         context_expression.into(),
                         "invalid-context-manager",
                         format_args!(
@@ -1332,9 +1346,11 @@ impl<'db> TypeInferenceBuilder<'db> {
 
                 let target_ty = enter_ty
                     .call(self.db, &[context_expression_ty])
-                    .return_ty_result(self.db, context_expression.into(), &mut self.diagnostics)
+                    .return_ty_result(self.db, self.file, context_expression.into(), )
                     .unwrap_or_else(|err| {
-                        self.diagnostics.add(
+                        report_type_diagnostic(
+                            self.db,
+                            self.file,
                             context_expression.into(),
                             "invalid-context-manager",
                             format_args!("
@@ -1346,7 +1362,9 @@ impl<'db> TypeInferenceBuilder<'db> {
 
                 match exit {
                     Symbol::Unbound => {
-                        self.diagnostics.add(
+                        report_type_diagnostic(
+                            self.db,
+                            self.file,
                             context_expression.into(),
                             "invalid-context-manager",
                             format_args!(
@@ -1359,7 +1377,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                         // TODO: Use the `exit_ty` to determine if any raised exception is suppressed.
 
                         if exit_boundness == Boundness::PossiblyUnbound {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 context_expression.into(),
                                 "invalid-context-manager",
                                 format_args!(
@@ -1379,14 +1399,12 @@ impl<'db> TypeInferenceBuilder<'db> {
                                     Type::none(self.db),
                                 ],
                             )
-                            .return_ty_result(
-                                self.db,
-                                context_expression.into(),
-                                &mut self.diagnostics,
-                            )
+                            .return_ty_result(self.db, self.file, context_expression.into())
                             .is_err()
                         {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 context_expression.into(),
                                 "invalid-context-manager",
                                 format_args!(
@@ -1466,7 +1484,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         let bound_or_constraint = match bound.as_deref() {
             Some(expr @ ast::Expr::Tuple(ast::ExprTuple { elts, .. })) => {
                 if elts.len() < 2 {
-                    self.diagnostics.add(
+                    report_type_diagnostic(
+                        self.db,
+                        self.file,
                         expr.into(),
                         "invalid-typevar-constraints",
                         format_args!("TypeVar must have at least two constrained types"),
@@ -1663,12 +1683,6 @@ impl<'db> TypeInferenceBuilder<'db> {
         let target_ty = match assignment.target() {
             TargetKind::Sequence(unpack) => {
                 let unpacked = infer_unpack_types(self.db, unpack);
-                // Only copy the diagnostics if this is the first assignment to avoid duplicating the
-                // unpack assignments.
-                if assignment.is_first() {
-                    self.diagnostics.extend(unpacked.diagnostics());
-                }
-
                 unpacked.get(name_ast_id).unwrap_or(Type::Unknown)
             }
             TargetKind::Name => value_ty,
@@ -1777,12 +1791,14 @@ impl<'db> TypeInferenceBuilder<'db> {
                     let call = class_member.call(self.db, &[target_type, value_type]);
                     let augmented_return_ty = match call.return_ty_result(
                         self.db,
+                        self.file,
                         AnyNodeRef::StmtAugAssign(assignment),
-                        &mut self.diagnostics,
                     ) {
                         Ok(t) => t,
                         Err(e) => {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 assignment.into(),
                                 "unsupported-operator",
                                 format_args!(
@@ -1803,7 +1819,9 @@ impl<'db> TypeInferenceBuilder<'db> {
 
                             let binary_return_ty = self.infer_binary_expression_type(left_ty, right_ty, op)
                                 .unwrap_or_else(|| {
-                                    self.diagnostics.add(
+                                    report_type_diagnostic(
+                                        self.db,
+                                        self.file,
                                         assignment.into(),
                                         "unsupported-operator",
                                         format_args!(
@@ -1832,7 +1850,9 @@ impl<'db> TypeInferenceBuilder<'db> {
 
         self.infer_binary_expression_type(left_ty, right_ty, op)
             .unwrap_or_else(|| {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     assignment.into(),
                     "unsupported-operator",
                     format_args!(
@@ -1919,7 +1939,7 @@ impl<'db> TypeInferenceBuilder<'db> {
         } else {
             iterable_ty
                 .iterate(self.db)
-                .unwrap_with_diagnostic(iterable.into(), &mut self.diagnostics)
+                .unwrap_with_diagnostic(self.db, self.file, iterable.into())
         };
 
         self.store_expression_type(target, loop_var_value_ty);
@@ -1958,7 +1978,7 @@ impl<'db> TypeInferenceBuilder<'db> {
             if let Some(module) = self.module_ty_from_name(&module_name) {
                 module
             } else {
-                self.diagnostics.add_unresolved_module(alias, 0, Some(name));
+                report_unresolved_module(self.db, self.file, alias, 0, Some(name));
                 Type::Unknown
             }
         } else {
@@ -2086,7 +2106,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     match module_ty.member(self.db, &ast::name::Name::new(&name.id)) {
                         Symbol::Type(ty, boundness) => {
                             if boundness == Boundness::PossiblyUnbound {
-                                self.diagnostics.add(
+                                report_type_diagnostic(
+                                    self.db,
+                                    self.file,
                                     AnyNodeRef::Alias(alias),
                                     "possibly-unbound-import",
                                     format_args!("Member `{name}` of module `{module_name}` is possibly unbound",),
@@ -2096,7 +2118,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                             ty
                         }
                         Symbol::Unbound => {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 AnyNodeRef::Alias(alias),
                                 "unresolved-import",
                                 format_args!("Module `{module_name}` has no member `{name}`",),
@@ -2105,8 +2129,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                         }
                     }
                 } else {
-                    self.diagnostics
-                        .add_unresolved_module(import_from, *level, module);
+                    report_unresolved_module(self.db, self.file, import_from, *level, module);
                     Type::Unknown
                 }
             }
@@ -2120,8 +2143,8 @@ impl<'db> TypeInferenceBuilder<'db> {
                     "Relative module resolution `{}` failed: too many leading dots",
                     format_import_from_module(*level, module),
                 );
-                self.diagnostics
-                    .add_unresolved_module(import_from, *level, module);
+
+                report_unresolved_module(self.db, self.file, import_from, *level, module);
                 Type::Unknown
             }
             Err(ModuleNameResolutionError::UnknownCurrentModule) => {
@@ -2130,8 +2153,8 @@ impl<'db> TypeInferenceBuilder<'db> {
                     format_import_from_module(*level, module),
                     self.file.path(self.db)
                 );
-                self.diagnostics
-                    .add_unresolved_module(import_from, *level, module);
+
+                report_unresolved_module(self.db, self.file, import_from, *level, module);
                 Type::Unknown
             }
         };
@@ -2596,7 +2619,7 @@ impl<'db> TypeInferenceBuilder<'db> {
         } else {
             iterable_ty
                 .iterate(self.db)
-                .unwrap_with_diagnostic(iterable.into(), &mut self.diagnostics)
+                .unwrap_with_diagnostic(self.db, self.file, iterable.into())
         };
 
         self.types.expressions.insert(
@@ -2697,7 +2720,7 @@ impl<'db> TypeInferenceBuilder<'db> {
         let function_type = self.infer_expression(func);
         function_type
             .call(self.db, arg_types.as_slice())
-            .unwrap_with_diagnostic(self.db, func.as_ref().into(), &mut self.diagnostics)
+            .unwrap_with_diagnostic(self.db, self.file, func.as_ref().into())
     }
 
     fn infer_starred_expression(&mut self, starred: &ast::ExprStarred) -> Type<'db> {
@@ -2708,9 +2731,11 @@ impl<'db> TypeInferenceBuilder<'db> {
         } = starred;
 
         let iterable_ty = self.infer_expression(value);
-        iterable_ty
-            .iterate(self.db)
-            .unwrap_with_diagnostic(value.as_ref().into(), &mut self.diagnostics);
+        iterable_ty.iterate(self.db).unwrap_with_diagnostic(
+            self.db,
+            self.file,
+            value.as_ref().into(),
+        );
 
         // TODO
         todo_type!()
@@ -2729,9 +2754,11 @@ impl<'db> TypeInferenceBuilder<'db> {
         let ast::ExprYieldFrom { range: _, value } = yield_from;
 
         let iterable_ty = self.infer_expression(value);
-        iterable_ty
-            .iterate(self.db)
-            .unwrap_with_diagnostic(value.as_ref().into(), &mut self.diagnostics);
+        iterable_ty.iterate(self.db).unwrap_with_diagnostic(
+            self.db,
+            self.file,
+            value.as_ref().into(),
+        );
 
         // TODO get type from `ReturnType` of generator
         todo_type!()
@@ -2803,7 +2830,9 @@ impl<'db> TypeInferenceBuilder<'db> {
             {
                 let mut builtins_symbol = builtins_symbol(self.db, name);
                 if builtins_symbol.is_unbound() && name == "reveal_type" {
-                    self.diagnostics.add(
+                    report_type_diagnostic(
+                        self.db,
+                        self.file,
                         name_node.into(),
                         "undefined-reveal",
                         format_args!(
@@ -2858,7 +2887,7 @@ impl<'db> TypeInferenceBuilder<'db> {
             match self.lookup_name(name) {
                 Symbol::Type(looked_up_ty, looked_up_boundness) => {
                     if looked_up_boundness == Boundness::PossiblyUnbound {
-                        self.diagnostics.add_possibly_unresolved_reference(name);
+                        report_possibly_unresolved_reference(self.db, self.file, name);
                     }
 
                     bindings_ty
@@ -2867,9 +2896,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                 }
                 Symbol::Unbound => {
                     if bindings_ty.is_some() {
-                        self.diagnostics.add_possibly_unresolved_reference(name);
+                        report_possibly_unresolved_reference(self.db, self.file, name);
                     } else {
-                        self.diagnostics.add_unresolved_reference(name);
+                        report_unresolved_reference(self.db, self.file, name);
                     }
                     bindings_ty.unwrap_or(Type::Unknown)
                 }
@@ -2900,7 +2929,9 @@ impl<'db> TypeInferenceBuilder<'db> {
         match value_ty.member(self.db, &attr.id) {
             Symbol::Type(member_ty, boundness) => {
                 if boundness == Boundness::PossiblyUnbound {
-                    self.diagnostics.add(
+                    report_type_diagnostic(
+                        self.db,
+                        self.file,
                         attribute.into(),
                         "possibly-unbound-attribute",
                         format_args!(
@@ -2914,7 +2945,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                 member_ty
             }
             Symbol::Unbound => {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     attribute.into(),
                     "unresolved-attribute",
                     format_args!(
@@ -2988,14 +3021,13 @@ impl<'db> TypeInferenceBuilder<'db> {
                 {
                     let call = class_member.call(self.db, &[operand_type]);
 
-                    match call.return_ty_result(
-                        self.db,
-                        AnyNodeRef::ExprUnaryOp(unary),
-                        &mut self.diagnostics,
-                    ) {
+                    match call.return_ty_result(self.db, self.file, AnyNodeRef::ExprUnaryOp(unary))
+                    {
                         Ok(t) => t,
                         Err(e) => {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 unary.into(),
                                 "unsupported-operator",
                                 format_args!(
@@ -3007,7 +3039,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                         }
                     }
                 } else {
-                    self.diagnostics.add(
+                    report_type_diagnostic(
+                        self.db,
+                        self.file,
                         unary.into(),
                         "unsupported-operator",
                         format_args!(
@@ -3048,7 +3082,9 @@ impl<'db> TypeInferenceBuilder<'db> {
 
         self.infer_binary_expression_type(left_ty, right_ty, *op)
             .unwrap_or_else(|| {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     binary.into(),
                     "unsupported-operator",
                     format_args!(
@@ -3358,7 +3394,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     self.infer_binary_type_comparison(left_ty, *op, right_ty)
                         .unwrap_or_else(|error| {
                             // Handle unsupported operators (diagnostic, `bool`/`Unknown` outcome)
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 AnyNodeRef::ExprCompare(compare),
                                 "unsupported-operator",
                                 format_args!(
@@ -3904,7 +3942,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     .py_index(i32::try_from(int).expect("checked in branch arm"))
                     .copied()
                     .unwrap_or_else(|_| {
-                        self.diagnostics.add_index_out_of_bounds(
+                        report_index_out_of_bounds(
+                            self.db,
+                            self.file,
                             "tuple",
                             value_node.into(),
                             value_ty,
@@ -3923,7 +3963,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     let new_elements: Vec<_> = new_elements.copied().collect();
                     Type::tuple(self.db, &new_elements)
                 } else {
-                    self.diagnostics.add_slice_step_size_zero(value_node.into());
+                    report_slice_step_size_zero(self.db, self.file, value_node.into());
                     Type::Unknown
                 }
             }
@@ -3937,7 +3977,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     .py_index(i32::try_from(int).expect("checked in branch arm"))
                     .map(|ch| Type::string_literal(self.db, &ch.to_string()))
                     .unwrap_or_else(|_| {
-                        self.diagnostics.add_index_out_of_bounds(
+                        report_index_out_of_bounds(
+                            self.db,
+                            self.file,
                             "string",
                             value_node.into(),
                             value_ty,
@@ -3957,7 +3999,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     let literal: String = new_chars.collect();
                     Type::string_literal(self.db, &literal)
                 } else {
-                    self.diagnostics.add_slice_step_size_zero(value_node.into());
+                    report_slice_step_size_zero(self.db, self.file, value_node.into());
                     Type::Unknown
                 };
                 result
@@ -3972,7 +4014,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     .py_index(i32::try_from(int).expect("checked in branch arm"))
                     .map(|byte| Type::bytes_literal(self.db, &[*byte]))
                     .unwrap_or_else(|_| {
-                        self.diagnostics.add_index_out_of_bounds(
+                        report_index_out_of_bounds(
+                            self.db,
+                            self.file,
                             "bytes literal",
                             value_node.into(),
                             value_ty,
@@ -3991,7 +4035,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     let new_bytes: Vec<u8> = new_bytes.copied().collect();
                     Type::bytes_literal(self.db, &new_bytes)
                 } else {
-                    self.diagnostics.add_slice_step_size_zero(value_node.into());
+                    report_slice_step_size_zero(self.db, self.file, value_node.into());
                     Type::Unknown
                 }
             }
@@ -4015,7 +4059,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                     Symbol::Unbound => {}
                     Symbol::Type(dunder_getitem_method, boundness) => {
                         if boundness == Boundness::PossiblyUnbound {
-                            self.diagnostics.add(
+                            report_type_diagnostic(
+                                self.db,
+                                self.file,
                                 value_node.into(),
                                 "call-possibly-unbound-method",
                                 format_args!(
@@ -4027,9 +4073,11 @@ impl<'db> TypeInferenceBuilder<'db> {
 
                         return dunder_getitem_method
                             .call(self.db, &[slice_ty])
-                            .return_ty_result(self.db, value_node.into(), &mut self.diagnostics)
+                            .return_ty_result(self.db, self.file, value_node.into())
                             .unwrap_or_else(|err| {
-                                self.diagnostics.add(
+                                report_type_diagnostic(
+                                    self.db,
+                                    self.file,
                                     value_node.into(),
                                     "call-non-callable",
                                     format_args!(
@@ -4059,7 +4107,9 @@ impl<'db> TypeInferenceBuilder<'db> {
                         Symbol::Unbound => {}
                         Symbol::Type(ty, boundness) => {
                             if boundness == Boundness::PossiblyUnbound {
-                                self.diagnostics.add(
+                                report_type_diagnostic(
+                                    self.db,
+                                    self.file,
                                     value_node.into(),
                                     "call-possibly-unbound-method",
                                     format_args!(
@@ -4071,9 +4121,11 @@ impl<'db> TypeInferenceBuilder<'db> {
 
                             return ty
                                 .call(self.db, &[slice_ty])
-                                .return_ty_result(self.db, value_node.into(), &mut self.diagnostics)
+                                .return_ty_result(self.db, self.file, value_node.into())
                                 .unwrap_or_else(|err| {
-                                    self.diagnostics.add(
+                                    report_type_diagnostic(
+                                        self.db,
+                                        self.file,
                                         value_node.into(),
                                         "call-non-callable",
                                         format_args!(
@@ -4092,13 +4144,17 @@ impl<'db> TypeInferenceBuilder<'db> {
                         return KnownClass::GenericAlias.to_instance(self.db);
                     }
 
-                    self.diagnostics.add_non_subscriptable(
+                    report_non_subscriptable(
+                        self.db,
+                        self.file,
                         value_node.into(),
                         value_ty,
                         "__class_getitem__",
                     );
                 } else {
-                    self.diagnostics.add_non_subscriptable(
+                    report_non_subscriptable(
+                        self.db,
+                        self.file,
                         value_node.into(),
                         value_ty,
                         "__getitem__",
@@ -4170,7 +4226,6 @@ impl<'db> TypeInferenceBuilder<'db> {
 
     pub(super) fn finish(mut self) -> TypeInference<'db> {
         self.infer_region();
-        self.types.diagnostics = self.diagnostics.finish();
         self.types.shrink_to_fit();
         self.types
     }
@@ -4215,7 +4270,9 @@ impl<'db> TypeInferenceBuilder<'db> {
             ast::Expr::Starred(starred) => self.infer_starred_expression(starred),
 
             ast::Expr::BytesLiteral(bytes) => {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     bytes.into(),
                     "annotation-byte-string",
                     format_args!("Type expressions cannot use bytes literal"),
@@ -4224,11 +4281,14 @@ impl<'db> TypeInferenceBuilder<'db> {
             }
 
             ast::Expr::FString(fstring) => {
-                self.diagnostics.add(
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
                     fstring.into(),
                     "annotation-f-string",
                     format_args!("Type expressions cannot use f-strings"),
                 );
+                self.infer_fstring_expression(fstring);
                 Type::Unknown
             }
 
@@ -4252,10 +4312,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     DeferredExpressionState::InStringAnnotation,
                 )
             }
-            Err(diagnostics) => {
-                self.diagnostics.extend(&diagnostics);
-                Type::Unknown
-            }
+            Err(()) => Type::Unknown,
         }
     }
 }
@@ -4374,6 +4431,10 @@ impl<'db> TypeInferenceBuilder<'db> {
                 todo_type!()
             }
 
+            // Avoid inferring the types of invalid type expressions that have been parsed from a
+            // string annotation, as they are not present in the semantic index.
+            _ if self.deferred_state.in_string_annotation() => Type::Unknown,
+
             // Forms which are invalid in the context of annotation expressions: we infer their
             // nested expressions as normal expressions, but the type of the top-level expression is
             // always `Type::Unknown` in these cases.
@@ -4457,7 +4518,6 @@ impl<'db> TypeInferenceBuilder<'db> {
                 self.infer_slice_expression(slice);
                 Type::Unknown
             }
-
             ast::Expr::IpyEscapeCommand(_) => todo!("Implement Ipy escape command support"),
         }
     }
@@ -4472,10 +4532,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                     DeferredExpressionState::InStringAnnotation,
                 )
             }
-            Err(diagnostics) => {
-                self.diagnostics.extend(&diagnostics);
-                Type::Unknown
-            }
+            Err(()) => Type::Unknown,
         }
     }
 
@@ -4533,7 +4590,7 @@ impl<'db> TypeInferenceBuilder<'db> {
                 if element_could_alter_type_of_whole_tuple(single_element, single_element_ty) {
                     todo_type!()
                 } else {
-                    Type::tuple(self.db, &[single_element_ty])
+                    Type::tuple(self.db, [single_element_ty])
                 }
             }
         }
@@ -4572,7 +4629,7 @@ impl<'db> TypeInferenceBuilder<'db> {
 
         match value_ty {
             Type::KnownInstance(known_instance) => {
-                self.infer_parameterized_known_instance_type_expression(known_instance, slice)
+                self.infer_parameterized_known_instance_type_expression(subscript, known_instance)
             }
             _ => {
                 self.infer_type_expression(slice);
@@ -4583,15 +4640,18 @@ impl<'db> TypeInferenceBuilder<'db> {
 
     fn infer_parameterized_known_instance_type_expression(
         &mut self,
+        subscript: &ast::ExprSubscript,
         known_instance: KnownInstanceType,
-        parameters: &ast::Expr,
     ) -> Type<'db> {
+        let parameters = &*subscript.slice;
         match known_instance {
             KnownInstanceType::Literal => match self.infer_literal_parameter_type(parameters) {
                 Ok(ty) => ty,
                 Err(nodes) => {
                     for node in nodes {
-                        self.diagnostics.add(
+                        report_type_diagnostic(
+                            self.db,
+                            self.file,
                             node.into(),
                             "invalid-literal-parameter",
                             format_args!(
@@ -4626,6 +4686,32 @@ impl<'db> TypeInferenceBuilder<'db> {
                 self.infer_type_expression(parameters);
                 todo_type!("generic type alias")
             }
+            KnownInstanceType::NoReturn | KnownInstanceType::Never => {
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
+                    subscript.into(),
+                    "invalid-type-parameter",
+                    format_args!(
+                        "Type `{}` expected no type parameter",
+                        known_instance.repr(self.db)
+                    ),
+                );
+                Type::Unknown
+            }
+            KnownInstanceType::LiteralString => {
+                report_type_diagnostic(
+                    self.db,
+                    self.file,
+                    subscript.into(),
+                    "invalid-type-parameter",
+                    format_args!(
+                        "Type `{}` expected no type parameter. Did you mean to use `Literal[...]` instead?",
+                        known_instance.repr(self.db)
+                    ),
+                );
+                Type::Unknown
+            }
         }
     }
 
@@ -5011,8 +5097,6 @@ fn perform_membership_test_comparison<'db>(
 
 #[cfg(test)]
 mod tests {
-    use anyhow::Context;
-
     use crate::db::tests::TestDb;
     use crate::program::{Program, SearchPathSettings};
     use crate::python_version::PythonVersion;
@@ -5021,6 +5105,8 @@ mod tests {
     use crate::semantic_index::{global_scope, semantic_index, symbol_table, use_def_map};
     use crate::types::check_types;
     use crate::{HasTy, ProgramSettings, SemanticModel};
+    use anyhow::Context;
+    use ruff_db::diagnostic::{CompileDiagnostic, Diagnostic};
     use ruff_db::files::{system_path_to_file, File};
     use ruff_db::parsed::parsed_module;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
@@ -5122,22 +5208,18 @@ mod tests {
     }
 
     #[track_caller]
-    fn assert_diagnostic_messages(diagnostics: &TypeCheckDiagnostics, expected: &[&str]) {
-        let messages: Vec<&str> = diagnostics
+    fn assert_file_diagnostics(db: &TestDb, filename: &str, expected: &[&str]) {
+        let file = system_path_to_file(db, filename).unwrap();
+
+        let diagnostics = check_types::accumulated::<CompileDiagnostic>(db, file);
+
+        let messages: Vec<_> = diagnostics
             .iter()
             .map(|diagnostic| diagnostic.message())
             .collect();
         assert_eq!(&messages, expected);
     }
 
-    #[track_caller]
-    fn assert_file_diagnostics(db: &TestDb, filename: &str, expected: &[&str]) {
-        let file = system_path_to_file(db, filename).unwrap();
-        let diagnostics = check_types(db, file);
-
-        assert_diagnostic_messages(diagnostics, expected);
-    }
-
     #[test]
     fn from_import_with_no_module_name() -> anyhow::Result<()> {
         // This test checks that invalid syntax in a `StmtImportFrom` node
@@ -5922,7 +6004,15 @@ mod tests {
         assert!(z.is_unbound());
 
         // (There is a diagnostic for invalid syntax that's emitted, but it's not listed by `assert_file_diagnostics`)
-        assert_file_diagnostics(&db, "src/a.py", &["Name `z` used when not defined"]);
+        assert_file_diagnostics(
+            &db,
+            "src/a.py",
+            &[
+                "Expected an identifier, but found a keyword 'in' that cannot be used here",
+                "Expected 'in', found name",
+                "Name `z` used when not defined",
+            ],
+        );
 
         Ok(())
     }
@@ -5970,7 +6060,11 @@ mod tests {
             "src/a.py",
             &["foo", "<listcomp>"],
             "x",
-            "@Todo(async iterables/iterators)",
+            if cfg!(debug_assertions) {
+                "@Todo(async iterables/iterators)"
+            } else {
+                "@Todo"
+            },
         );
 
         Ok(())
@@ -6000,7 +6094,11 @@ mod tests {
             "src/a.py",
             &["foo", "<listcomp>"],
             "x",
-            "@Todo(async iterables/iterators)",
+            if cfg!(debug_assertions) {
+                "@Todo(async iterables/iterators)"
+            } else {
+                "@Todo"
+            },
         );
 
         Ok(())
@@ -6035,6 +6133,72 @@ mod tests {
         );
     }
 
+    #[test]
+    fn pep695_type_params() {
+        let mut db = setup_db();
+
+        db.write_dedented(
+            "src/a.py",
+            "
+            def f[T, U: A, V: (A, B), W = A, X: A = A1, Y: (int,)]():
+                pass
+
+            class A: ...
+            class B: ...
+            class A1(A): ...
+            ",
+        )
+        .unwrap();
+
+        let check_typevar = |var: &'static str,
+                             upper_bound: Option<&'static str>,
+                             constraints: Option<&[&'static str]>,
+                             default: Option<&'static str>| {
+            let var_ty = get_symbol(&db, "src/a.py", &["f"], var).expect_type();
+            assert_eq!(var_ty.display(&db).to_string(), var);
+
+            let expected_name_ty = format!(r#"Literal["{var}"]"#);
+            let name_ty = var_ty.member(&db, "__name__").expect_type();
+            assert_eq!(name_ty.display(&db).to_string(), expected_name_ty);
+
+            let KnownInstanceType::TypeVar(typevar) = var_ty.expect_known_instance() else {
+                panic!("expected TypeVar");
+            };
+
+            assert_eq!(
+                typevar
+                    .upper_bound(&db)
+                    .map(|ty| ty.display(&db).to_string()),
+                upper_bound.map(std::borrow::ToOwned::to_owned)
+            );
+            assert_eq!(
+                typevar.constraints(&db).map(|tys| tys
+                    .iter()
+                    .map(|ty| ty.display(&db).to_string())
+                    .collect::<Vec<_>>()),
+                constraints.map(|strings| strings
+                    .iter()
+                    .map(std::string::ToString::to_string)
+                    .collect::<Vec<_>>())
+            );
+            assert_eq!(
+                typevar
+                    .default_ty(&db)
+                    .map(|ty| ty.display(&db).to_string()),
+                default.map(std::borrow::ToOwned::to_owned)
+            );
+        };
+
+        check_typevar("T", None, None, None);
+        check_typevar("U", Some("A"), None, None);
+        check_typevar("V", None, Some(&["A", "B"]), None);
+        check_typevar("W", None, None, Some("A"));
+        check_typevar("X", Some("A"), None, Some("A1"));
+
+        // a typevar with less than two constraints is treated as unconstrained
+        check_typevar("Y", None, None, None);
+    }
+
     // Incremental inference tests
 
     fn first_public_binding<'db>(db: &'db TestDb, file: File, name: &str) -> Definition<'db> {

crates/red_knot_python_semantic/src/types/mro.rs

@@ -374,7 +374,10 @@ impl<'db> ClassBase<'db> {
                 KnownInstanceType::TypeVar(_)
                 | KnownInstanceType::TypeAliasType(_)
                 | KnownInstanceType::Literal
+                | KnownInstanceType::LiteralString
                 | KnownInstanceType::Union
+                | KnownInstanceType::NoReturn
+                | KnownInstanceType::Never
                 | KnownInstanceType::Optional => None,
             },
         }

crates/red_knot_python_semantic/src/types/narrow.rs

@@ -54,6 +54,7 @@ pub(crate) fn narrowing_constraint<'db>(
     }
 }
 
+#[allow(clippy::ref_option)]
 #[salsa::tracked(return_ref)]
 fn all_narrowing_constraints_for_pattern<'db>(
     db: &'db dyn Db,
@@ -62,6 +63,7 @@ fn all_narrowing_constraints_for_pattern<'db>(
     NarrowingConstraintsBuilder::new(db, ConstraintNode::Pattern(pattern), true).finish()
 }
 
+#[allow(clippy::ref_option)]
 #[salsa::tracked(return_ref)]
 fn all_narrowing_constraints_for_expression<'db>(
     db: &'db dyn Db,
@@ -70,6 +72,7 @@ fn all_narrowing_constraints_for_expression<'db>(
     NarrowingConstraintsBuilder::new(db, ConstraintNode::Expression(expression), true).finish()
 }
 
+#[allow(clippy::ref_option)]
 #[salsa::tracked(return_ref)]
 fn all_negative_narrowing_constraints_for_expression<'db>(
     db: &'db dyn Db,
@@ -291,8 +294,15 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
             .chain(comparators)
             .tuple_windows::<(&ruff_python_ast::Expr, &ruff_python_ast::Expr)>();
         let mut constraints = NarrowingConstraints::default();
+
+        let mut last_rhs_ty: Option<Type> = None;
+
         for (op, (left, right)) in std::iter::zip(&**ops, comparator_tuples) {
+            let lhs_ty = last_rhs_ty.unwrap_or_else(|| {
+                inference.expression_ty(left.scoped_expression_id(self.db, scope))
+            });
             let rhs_ty = inference.expression_ty(right.scoped_expression_id(self.db, scope));
+            last_rhs_ty = Some(rhs_ty);
 
             match left {
                 ast::Expr::Name(ast::ExprName {
@@ -327,6 +337,9 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
                                 constraints.insert(symbol, ty);
                             }
                         }
+                        ast::CmpOp::Eq if lhs_ty.is_literal_string() => {
+                            constraints.insert(symbol, rhs_ty);
+                        }
                         _ => {
                             // TODO other comparison types
                         }
@@ -385,46 +398,58 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         let scope = self.scope();
         let inference = infer_expression_types(self.db, expression);
 
+        let callable_ty =
+            inference.expression_ty(expr_call.func.scoped_expression_id(self.db, scope));
+
         // TODO: add support for PEP 604 union types on the right hand side of `isinstance`
         // and `issubclass`, for example `isinstance(x, str | (int | float))`.
-        match inference
-            .expression_ty(expr_call.func.scoped_expression_id(self.db, scope))
-            .into_function_literal()
-            .and_then(|f| f.known(self.db))
-            .and_then(KnownFunction::constraint_function)
-        {
-            Some(function) if expr_call.arguments.keywords.is_empty() => {
-                if let [ast::Expr::Name(ast::ExprName { id, .. }), class_info] =
+        match callable_ty {
+            Type::FunctionLiteral(function_type) if expr_call.arguments.keywords.is_empty() => {
+                let function = function_type
+                    .known(self.db)
+                    .and_then(KnownFunction::constraint_function)?;
+
+                let [ast::Expr::Name(ast::ExprName { id, .. }), class_info] =
                     &*expr_call.arguments.args
-                {
-                    let symbol = self.symbols().symbol_id_by_name(id).unwrap();
+                else {
+                    return None;
+                };
 
-                    let class_info_ty =
-                        inference.expression_ty(class_info.scoped_expression_id(self.db, scope));
+                let symbol = self.symbols().symbol_id_by_name(id).unwrap();
 
-                    let to_constraint = match function {
-                        KnownConstraintFunction::IsInstance => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::instance(class_literal.class)
-                            }
+                let class_info_ty =
+                    inference.expression_ty(class_info.scoped_expression_id(self.db, scope));
+
+                let to_constraint = match function {
+                    KnownConstraintFunction::IsInstance => {
+                        |class_literal: ClassLiteralType<'db>| Type::instance(class_literal.class)
+                    }
+                    KnownConstraintFunction::IsSubclass => {
+                        |class_literal: ClassLiteralType<'db>| {
+                            Type::subclass_of(class_literal.class)
                         }
-                        KnownConstraintFunction::IsSubclass => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::subclass_of(class_literal.class)
-                            }
-                        }
-                    };
+                    }
+                };
 
-                    generate_classinfo_constraint(self.db, &class_info_ty, to_constraint).map(
-                        |constraint| {
-                            let mut constraints = NarrowingConstraints::default();
-                            constraints.insert(symbol, constraint.negate_if(self.db, !is_positive));
-                            constraints
-                        },
-                    )
-                } else {
-                    None
-                }
+                generate_classinfo_constraint(self.db, &class_info_ty, to_constraint).map(
+                    |constraint| {
+                        let mut constraints = NarrowingConstraints::default();
+                        constraints.insert(symbol, constraint.negate_if(self.db, !is_positive));
+                        constraints
+                    },
+                )
+            }
+            // for the expression `bool(E)`, we further narrow the type based on `E`
+            Type::ClassLiteral(class_type)
+                if expr_call.arguments.args.len() == 1
+                    && expr_call.arguments.keywords.is_empty()
+                    && class_type.class.is_known(self.db, KnownClass::Bool) =>
+            {
+                self.evaluate_expression_node_constraint(
+                    &expr_call.arguments.args[0],
+                    expression,
+                    is_positive,
+                )
             }
             _ => None,
         }

crates/red_knot_python_semantic/src/types/property_tests.rs

@@ -0,0 +1,237 @@
+//! This module contains quickcheck-based property tests for `Type`s.
+//!
+//! These tests are disabled by default, as they are non-deterministic and slow. You can
+//! run them explicitly using:
+//!
+//! ```sh
+//! cargo test -p red_knot_python_semantic -- --ignored types::property_tests::stable
+//! ```
+//!
+//! The number of tests (default: 100) can be controlled by setting the `QUICKCHECK_TESTS`
+//! environment variable. For example:
+//!
+//! ```sh
+//! QUICKCHECK_TESTS=10000 cargo test …
+//! ```
+//!
+//! If you want to run these tests for a longer period of time, it's advisable to run them
+//! in release mode. As some tests are slower than others, it's advisable to run them in a
+//! loop until they fail:
+//!
+//! ```sh
+//! export QUICKCHECK_TESTS=100000
+//! while cargo test --release -p red_knot_python_semantic -- \
+//!   --ignored types::property_tests::stable; do :; done
+//! ```
+
+use std::sync::{Arc, Mutex, MutexGuard, OnceLock};
+
+use super::tests::{setup_db, Ty};
+use crate::db::tests::TestDb;
+use crate::types::KnownClass;
+use quickcheck::{Arbitrary, Gen};
+
+fn arbitrary_core_type(g: &mut Gen) -> Ty {
+    // We could select a random integer here, but this would make it much less
+    // likely to explore interesting edge cases:
+    let int_lit = Ty::IntLiteral(*g.choose(&[-2, -1, 0, 1, 2]).unwrap());
+    let bool_lit = Ty::BooleanLiteral(bool::arbitrary(g));
+    g.choose(&[
+        Ty::Never,
+        Ty::Unknown,
+        Ty::None,
+        Ty::Any,
+        int_lit,
+        bool_lit,
+        Ty::StringLiteral(""),
+        Ty::StringLiteral("a"),
+        Ty::LiteralString,
+        Ty::BytesLiteral(""),
+        Ty::BytesLiteral("\x00"),
+        Ty::KnownClassInstance(KnownClass::Object),
+        Ty::KnownClassInstance(KnownClass::Str),
+        Ty::KnownClassInstance(KnownClass::Int),
+        Ty::KnownClassInstance(KnownClass::Bool),
+        Ty::KnownClassInstance(KnownClass::List),
+        Ty::KnownClassInstance(KnownClass::Tuple),
+        Ty::KnownClassInstance(KnownClass::FunctionType),
+        Ty::KnownClassInstance(KnownClass::SpecialForm),
+        Ty::KnownClassInstance(KnownClass::TypeVar),
+        Ty::KnownClassInstance(KnownClass::TypeAliasType),
+        Ty::KnownClassInstance(KnownClass::NoDefaultType),
+        Ty::TypingLiteral,
+        Ty::BuiltinClassLiteral("str"),
+        Ty::BuiltinClassLiteral("int"),
+        Ty::BuiltinClassLiteral("bool"),
+        Ty::BuiltinClassLiteral("object"),
+    ])
+    .unwrap()
+    .clone()
+}
+
+/// Constructs an arbitrary type.
+///
+/// The `size` parameter controls the depth of the type tree. For example,
+/// a simple type like `int` has a size of 0, `Union[int, str]` has a size
+/// of 1, `tuple[int, Union[str, bytes]]` has a size of 2, etc.
+fn arbitrary_type(g: &mut Gen, size: u32) -> Ty {
+    if size == 0 {
+        arbitrary_core_type(g)
+    } else {
+        match u32::arbitrary(g) % 4 {
+            0 => arbitrary_core_type(g),
+            1 => Ty::Union(
+                (0..*g.choose(&[2, 3]).unwrap())
+                    .map(|_| arbitrary_type(g, size - 1))
+                    .collect(),
+            ),
+            2 => Ty::Tuple(
+                (0..*g.choose(&[0, 1, 2]).unwrap())
+                    .map(|_| arbitrary_type(g, size - 1))
+                    .collect(),
+            ),
+            3 => Ty::Intersection {
+                pos: (0..*g.choose(&[0, 1, 2]).unwrap())
+                    .map(|_| arbitrary_type(g, size - 1))
+                    .collect(),
+                neg: (0..*g.choose(&[0, 1, 2]).unwrap())
+                    .map(|_| arbitrary_type(g, size - 1))
+                    .collect(),
+            },
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl Arbitrary for Ty {
+    fn arbitrary(g: &mut Gen) -> Ty {
+        const MAX_SIZE: u32 = 2;
+        arbitrary_type(g, MAX_SIZE)
+    }
+
+    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
+        // This is incredibly naive. We can do much better here by
+        // trying various subsets of the elements in unions, tuples,
+        // and intersections. For now, we only try to shrink by
+        // reducing unions/tuples/intersections to a single element.
+        match self.clone() {
+            Ty::Union(types) => Box::new(types.into_iter()),
+            Ty::Tuple(types) => Box::new(types.into_iter()),
+            Ty::Intersection { pos, neg } => Box::new(pos.into_iter().chain(neg)),
+            _ => Box::new(std::iter::empty()),
+        }
+    }
+}
+
+static CACHED_DB: OnceLock<Arc<Mutex<TestDb>>> = OnceLock::new();
+
+fn get_cached_db() -> MutexGuard<'static, TestDb> {
+    let db = CACHED_DB.get_or_init(|| Arc::new(Mutex::new(setup_db())));
+    db.lock().unwrap()
+}
+
+/// A macro to define a property test for types.
+///
+/// The `$test_name` identifier specifies the name of the test function. The `$db` identifier
+/// is used to refer to the salsa database in the property to be tested. The actual property is
+/// specified using the syntax:
+///
+///     forall types t1, t2, ..., tn . <property>`
+///
+/// where `t1`, `t2`, ..., `tn` are identifiers that represent arbitrary types, and `<property>`
+/// is an expression using these identifiers.
+///
+macro_rules! type_property_test {
+    ($test_name:ident, $db:ident, forall types $($types:ident),+ . $property:expr) => {
+        #[quickcheck_macros::quickcheck]
+        #[ignore]
+        fn $test_name($($types: crate::types::tests::Ty),+) -> bool {
+            let db_cached = super::get_cached_db();
+            let $db = &*db_cached;
+            $(let $types = $types.into_type($db);)+
+
+            $property
+        }
+    };
+    // A property test with a logical implication.
+    ($name:ident, $db:ident, forall types $($types:ident),+ . $premise:expr => $conclusion:expr) => {
+        type_property_test!($name, $db, forall types $($types),+ . !($premise) || ($conclusion));
+    };
+}
+
+mod stable {
+    // `T` is equivalent to itself.
+    type_property_test!(
+        equivalent_to_is_reflexive, db,
+        forall types t. t.is_equivalent_to(db, t)
+    );
+
+    // `T` is a subtype of itself.
+    type_property_test!(
+        subtype_of_is_reflexive, db,
+        forall types t. t.is_subtype_of(db, t)
+    );
+
+    // `S <: T` and `T <: U` implies that `S <: U`.
+    type_property_test!(
+        subtype_of_is_transitive, db,
+        forall types s, t, u. s.is_subtype_of(db, t) && t.is_subtype_of(db, u) => s.is_subtype_of(db, u)
+    );
+
+    // `T` is not disjoint from itself, unless `T` is `Never`.
+    type_property_test!(
+        disjoint_from_is_irreflexive, db,
+        forall types t. t.is_disjoint_from(db, t) => t.is_never()
+    );
+
+    // `S` is disjoint from `T` implies that `T` is disjoint from `S`.
+    type_property_test!(
+        disjoint_from_is_symmetric, db,
+        forall types s, t. s.is_disjoint_from(db, t) == t.is_disjoint_from(db, s)
+    );
+
+    // `S <: T` implies that `S` is not disjoint from `T`, unless `S` is `Never`.
+    type_property_test!(
+        subtype_of_implies_not_disjoint_from, db,
+        forall types s, t. s.is_subtype_of(db, t) => !s.is_disjoint_from(db, t) || s.is_never()
+    );
+
+    // `T` can be assigned to itself.
+    type_property_test!(
+        assignable_to_is_reflexive, db,
+        forall types t. t.is_assignable_to(db, t)
+    );
+
+    // `S <: T` implies that `S` can be assigned to `T`.
+    type_property_test!(
+        subtype_of_implies_assignable_to, db,
+        forall types s, t. s.is_subtype_of(db, t) => s.is_assignable_to(db, t)
+    );
+
+    // If `T` is a singleton, it is also single-valued.
+    type_property_test!(
+        singleton_implies_single_valued, db,
+        forall types t. t.is_singleton(db) => t.is_single_valued(db)
+    );
+}
+
+/// This module contains property tests that currently lead to many false positives.
+///
+/// The reason for this is our insufficient understanding of equivalence of types. For
+/// example, we currently consider `int | str` and `str | int` to be different types.
+/// Similar issues exist for intersection types. Once this is resolved, we can move these
+/// tests to the `stable` section. In the meantime, it can still be useful to run these
+/// tests (using [`types::property_tests::flaky`]), to see if there are any new obvious bugs.
+mod flaky {
+    // `S <: T` and `T <: S` implies that `S` is equivalent to `T`.
+    type_property_test!(
+        subtype_of_is_antisymmetric, db,
+        forall types s, t. s.is_subtype_of(db, t) && t.is_subtype_of(db, s) => s.is_equivalent_to(db, t)
+    );
+
+    // Negating `T` twice is equivalent to `T`.
+    type_property_test!(
+        double_negation_is_identity, db,
+        forall types t. t.negate(db).negate(db).is_equivalent_to(db, t)
+    );
+}

crates/red_knot_python_semantic/src/types/string_annotation.rs

@@ -5,10 +5,10 @@ use ruff_python_ast::{self as ast, ModExpression, StringFlags};
 use ruff_python_parser::{parse_expression_range, Parsed};
 use ruff_text_size::Ranged;
 
-use crate::types::diagnostic::{TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
+use crate::types::diagnostic::report_type_diagnostic;
 use crate::Db;
 
-type AnnotationParseResult = Result<Parsed<ModExpression>, TypeCheckDiagnostics>;
+type AnnotationParseResult = Result<Parsed<ModExpression>, ()>;
 
 /// Parses the given expression as a string annotation.
 pub(crate) fn parse_string_annotation(
@@ -20,12 +20,13 @@ pub(crate) fn parse_string_annotation(
 
     let source = source_text(db.upcast(), file);
     let node_text = &source[string_expr.range()];
-    let mut diagnostics = TypeCheckDiagnosticsBuilder::new(db, file);
 
     if let [string_literal] = string_expr.value.as_slice() {
         let prefix = string_literal.flags.prefix();
         if prefix.is_raw() {
-            diagnostics.add(
+            report_type_diagnostic(
+                db,
+                file,
                 string_literal.into(),
                 "annotation-raw-string",
                 format_args!("Type expressions cannot use raw string literal"),
@@ -49,7 +50,9 @@ pub(crate) fn parse_string_annotation(
             // ```
             match parse_expression_range(source.as_str(), range_excluding_quotes) {
                 Ok(parsed) => return Ok(parsed),
-                Err(parse_error) => diagnostics.add(
+                Err(parse_error) => report_type_diagnostic(
+                    db,
+                    file,
                     string_literal.into(),
                     "forward-annotation-syntax-error",
                     format_args!("Syntax error in forward annotation: {}", parse_error.error),
@@ -58,7 +61,9 @@ pub(crate) fn parse_string_annotation(
         } else {
             // The raw contents of the string doesn't match the parsed content. This could be the
             // case for annotations that contain escape sequences.
-            diagnostics.add(
+            report_type_diagnostic(
+                db,
+                file,
                 string_expr.into(),
                 "annotation-escape-character",
                 format_args!("Type expressions cannot contain escape characters"),
@@ -66,12 +71,14 @@ pub(crate) fn parse_string_annotation(
         }
     } else {
         // String is implicitly concatenated.
-        diagnostics.add(
+        report_type_diagnostic(
+            db,
+            file,
             string_expr.into(),
             "annotation-implicit-concat",
             format_args!("Type expressions cannot span multiple string literals"),
         );
     }
 
-    Err(diagnostics.finish())
+    Err(())
 }

crates/red_knot_python_semantic/src/types/unpacker.rs

@@ -6,22 +6,22 @@ use rustc_hash::FxHashMap;
 
 use crate::semantic_index::ast_ids::{HasScopedExpressionId, ScopedExpressionId};
 use crate::semantic_index::symbol::ScopeId;
-use crate::types::{todo_type, Type, TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
+use crate::types::{todo_type, Type};
 use crate::Db;
 
 /// Unpacks the value expression type to their respective targets.
 pub(crate) struct Unpacker<'db> {
     db: &'db dyn Db,
+    file: File,
     targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnosticsBuilder<'db>,
 }
 
 impl<'db> Unpacker<'db> {
     pub(crate) fn new(db: &'db dyn Db, file: File) -> Self {
         Self {
             db,
+            file,
             targets: FxHashMap::default(),
-            diagnostics: TypeCheckDiagnosticsBuilder::new(db, file),
         }
     }
 
@@ -95,7 +95,7 @@ impl<'db> Unpacker<'db> {
                     // there would be a cost and it's not clear that it's worth it.
                     let value_ty = Type::tuple(
                         self.db,
-                        &vec![Type::LiteralString; string_literal_ty.len(self.db)],
+                        std::iter::repeat(Type::LiteralString).take(string_literal_ty.len(self.db)),
                     );
                     self.unpack(target, value_ty, scope);
                 }
@@ -103,9 +103,11 @@ impl<'db> Unpacker<'db> {
                     let value_ty = if value_ty.is_literal_string() {
                         Type::LiteralString
                     } else {
-                        value_ty
-                            .iterate(self.db)
-                            .unwrap_with_diagnostic(AnyNodeRef::from(target), &mut self.diagnostics)
+                        value_ty.iterate(self.db).unwrap_with_diagnostic(
+                            self.db,
+                            self.file,
+                            AnyNodeRef::from(target),
+                        )
                     };
                     for element in elts {
                         self.unpack(element, value_ty, scope);
@@ -119,7 +121,6 @@ impl<'db> Unpacker<'db> {
     pub(crate) fn finish(mut self) -> UnpackResult<'db> {
         self.targets.shrink_to_fit();
         UnpackResult {
-            diagnostics: self.diagnostics.finish(),
             targets: self.targets,
         }
     }
@@ -128,15 +129,10 @@ impl<'db> Unpacker<'db> {
 #[derive(Debug, Default, PartialEq, Eq)]
 pub(crate) struct UnpackResult<'db> {
     targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnostics,
 }
 
 impl<'db> UnpackResult<'db> {
     pub(crate) fn get(&self, expr_id: ScopedExpressionId) -> Option<Type<'db>> {
         self.targets.get(&expr_id).copied()
     }
-
-    pub(crate) fn diagnostics(&self) -> &TypeCheckDiagnostics {
-        &self.diagnostics
-    }
 }

crates/red_knot_python_semantic/tests/mdtest.rs

@@ -1,7 +1,6 @@
-use std::ffi::OsStr;
-use std::path::Path;
-
+use camino::Utf8Path;
 use dir_test::{dir_test, Fixture};
+use std::path::Path;
 
 /// See `crates/red_knot_test/README.md` for documentation on these tests.
 #[dir_test(
@@ -10,16 +9,46 @@ use dir_test::{dir_test, Fixture};
 )]
 #[allow(clippy::needless_pass_by_value)]
 fn mdtest(fixture: Fixture<&str>) {
-    let fixture_path = Path::new(fixture.path());
+    let fixture_path = Utf8Path::new(fixture.path());
     let crate_dir = Path::new(env!("CARGO_MANIFEST_DIR"));
-    let workspace_root = crate_dir.parent().and_then(Path::parent).unwrap();
+    let workspace_root = crate_dir.ancestors().nth(2).unwrap();
 
-    let long_title = fixture_path
-        .strip_prefix(workspace_root)
-        .unwrap()
-        .to_str()
-        .unwrap();
-    let short_title = fixture_path.file_name().and_then(OsStr::to_str).unwrap();
+    let long_title = fixture_path.strip_prefix(workspace_root).unwrap();
+    let short_title = fixture_path.file_name().unwrap();
 
-    red_knot_test::run(fixture_path, long_title, short_title);
+    let test_name = test_name("mdtest", fixture_path);
+
+    red_knot_test::run(fixture_path, long_title.as_str(), short_title, &test_name);
+}
+
+/// Constructs the test name used for individual markdown files
+///
+/// This code is copied from <https://github.com/fe-lang/dir-test/blob/1c0f41c480a3490bc2653a043ff6e3f8085a1f47/macros/src/lib.rs#L104-L138>
+/// and should be updated if they diverge
+fn test_name(test_func_name: &str, fixture_path: &Utf8Path) -> String {
+    assert!(fixture_path.is_file());
+
+    let dir_path = format!("{}/resources/mdtest", std::env!("CARGO_MANIFEST_DIR"));
+    let rel_path = fixture_path.strip_prefix(dir_path).unwrap();
+    assert!(rel_path.is_relative());
+
+    let mut test_name = test_func_name.to_owned();
+    test_name.push_str("__");
+
+    for component in rel_path.parent().unwrap().components() {
+        let component = component
+            .as_str()
+            .replace(|c: char| c.is_ascii_punctuation(), "_");
+        test_name.push_str(&component);
+        test_name.push('_');
+    }
+
+    test_name.push_str(
+        &rel_path
+            .file_stem()
+            .unwrap()
+            .replace(|c: char| c.is_ascii_punctuation(), "_"),
+    );
+
+    test_name
 }

crates/red_knot_server/src/server/api.rs

@@ -91,11 +91,11 @@ fn background_request_task<'a, R: traits::BackgroundDocumentRequestHandler>(
         let db = match path {
             AnySystemPath::System(path) => {
                 match session.workspace_db_for_path(path.as_std_path()) {
-                    Some(db) => db.snapshot(),
-                    None => session.default_workspace_db().snapshot(),
+                    Some(db) => db.clone(),
+                    None => session.default_workspace_db().clone(),
                 }
             }
-            AnySystemPath::SystemVirtual(_) => session.default_workspace_db().snapshot(),
+            AnySystemPath::SystemVirtual(_) => session.default_workspace_db().clone(),
         };
 
         let Some(snapshot) = session.take_snapshot(url) else {

crates/red_knot_server/src/server/client.rs

@@ -26,7 +26,7 @@ pub(crate) struct Requester<'s> {
     response_handlers: FxHashMap<lsp_server::RequestId, ResponseBuilder<'s>>,
 }
 
-impl<'s> Client<'s> {
+impl Client<'_> {
     pub(super) fn new(sender: ClientSender) -> Self {
         Self {
             notifier: Notifier(sender.clone()),

crates/red_knot_test/Cargo.toml

@@ -20,6 +20,7 @@ ruff_source_file = { workspace = true }
 ruff_text_size = { workspace = true }
 
 anyhow = { workspace = true }
+camino = { workspace = true }
 colored = { workspace = true }
 memchr = { workspace = true }
 regex = { workspace = true }

crates/red_knot_test/README.md

@@ -184,8 +184,11 @@ The tests are run independently, in independent in-memory file systems and with
 [Salsa](https://github.com/salsa-rs/salsa) databases. This means that each is a from-scratch run of
 the type checker, with no data persisting from any previous test.
 
-Due to `cargo test` limitations, an entire test suite (Markdown file) is run as a single Rust test,
-so it's not possible to select individual tests within it to run.
+It is possible to filter to individual tests within a single markdown file using the
+`MDTEST_TEST_FILTER` environment variable. This variable will match any tests which contain the
+value as a case-sensitive substring in its name. An example test name is
+`unpacking.md - Unpacking - Tuple - Multiple assignment`, which contains the name of the markdown
+file and its parent headers joined together with hyphens.
 
 ## Structured test suites
 

crates/red_knot_test/src/db.rs

@@ -7,6 +7,7 @@ use ruff_db::vendored::VendoredFileSystem;
 use ruff_db::{Db as SourceDb, Upcast};
 
 #[salsa::db]
+#[derive(Clone)]
 pub(crate) struct Db {
     workspace_root: SystemPathBuf,
     storage: salsa::Storage<Self>,

crates/red_knot_test/src/lib.rs

@@ -1,13 +1,12 @@
+use camino::Utf8Path;
 use colored::Colorize;
 use parser as test_parser;
 use red_knot_python_semantic::types::check_types;
-use ruff_db::diagnostic::{Diagnostic, ParseDiagnostic};
+use ruff_db::diagnostic::{CompileDiagnostic, Diagnostic};
 use ruff_db::files::{system_path_to_file, File, Files};
-use ruff_db::parsed::parsed_module;
 use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
 use ruff_source_file::LineIndex;
 use ruff_text_size::TextSize;
-use std::path::Path;
 
 mod assertion;
 mod db;
@@ -15,23 +14,30 @@ mod diagnostic;
 mod matcher;
 mod parser;
 
+const MDTEST_TEST_FILTER: &str = "MDTEST_TEST_FILTER";
+
 /// Run `path` as a markdown test suite with given `title`.
 ///
 /// Panic on test failure, and print failure details.
 #[allow(clippy::print_stdout)]
-pub fn run(path: &Path, long_title: &str, short_title: &str) {
+pub fn run(path: &Utf8Path, long_title: &str, short_title: &str, test_name: &str) {
     let source = std::fs::read_to_string(path).unwrap();
     let suite = match test_parser::parse(short_title, &source) {
         Ok(suite) => suite,
         Err(err) => {
-            panic!("Error parsing `{}`: {err}", path.to_str().unwrap())
+            panic!("Error parsing `{path}`: {err}")
         }
     };
 
     let mut db = db::Db::setup(SystemPathBuf::from("/src"));
 
+    let filter = std::env::var(MDTEST_TEST_FILTER).ok();
     let mut any_failures = false;
     for test in suite.tests() {
+        if filter.as_ref().is_some_and(|f| !test.name().contains(f)) {
+            continue;
+        }
+
         // Remove all files so that the db is in a "fresh" state.
         db.memory_file_system().remove_all();
         Files::sync_all(&mut db);
@@ -54,6 +60,15 @@ pub fn run(path: &Path, long_title: &str, short_title: &str) {
                     }
                 }
             }
+
+            println!(
+                "\nTo rerun this specific test, set the environment variable: {MDTEST_TEST_FILTER}=\"{}\"",
+                test.name()
+            );
+            println!(
+                "{MDTEST_TEST_FILTER}=\"{}\" cargo test -p red_knot_python_semantic --test mdtest -- {test_name}",
+                test.name()
+            );
         }
     }
 
@@ -86,24 +101,9 @@ fn run_test(db: &mut db::Db, test: &parser::MarkdownTest) -> Result<(), Failures
     let failures: Failures = test_files
         .into_iter()
         .filter_map(|test_file| {
-            let parsed = parsed_module(db, test_file.file);
-
-            let mut diagnostics: Vec<Box<_>> = parsed
-                .errors()
-                .iter()
-                .cloned()
-                .map(|error| {
-                    let diagnostic: Box<dyn Diagnostic> =
-                        Box::new(ParseDiagnostic::new(test_file.file, error));
-                    diagnostic
-                })
-                .collect();
-
-            let type_diagnostics = check_types(db, test_file.file);
-            diagnostics.extend(type_diagnostics.into_iter().map(|diagnostic| {
-                let diagnostic: Box<dyn Diagnostic> = Box::new((*diagnostic).clone());
-                diagnostic
-            }));
+            let mut diagnostics = check_types::accumulated::<CompileDiagnostic>(db, test_file.file);
+            // Filter out diagnostics that are not related to the current file.
+            diagnostics.retain(|diagnostic| diagnostic.file() == test_file.file);
 
             match matcher::match_file(db, test_file.file, diagnostics) {
                 Ok(()) => None,

crates/red_knot_test/src/matcher.rs

@@ -180,6 +180,16 @@ where
     }
 }
 
+/// Discard `@Todo`-type metadata from expected types, which is not available
+/// when running in release mode.
+#[cfg(not(debug_assertions))]
+fn discard_todo_metadata(ty: &str) -> std::borrow::Cow<'_, str> {
+    static TODO_METADATA_REGEX: std::sync::LazyLock<regex::Regex> =
+        std::sync::LazyLock::new(|| regex::Regex::new(r"@Todo\([^)]*\)").unwrap());
+
+    TODO_METADATA_REGEX.replace_all(ty, "@Todo")
+}
+
 struct Matcher {
     line_index: LineIndex,
     source: SourceText,
@@ -276,6 +286,9 @@ impl Matcher {
                 }
             }
             Assertion::Revealed(expected_type) => {
+                #[cfg(not(debug_assertions))]
+                let expected_type = discard_todo_metadata(&expected_type);
+
                 let mut matched_revealed_type = None;
                 let mut matched_undefined_reveal = None;
                 let expected_reveal_type_message = format!("Revealed type is `{expected_type}`");

crates/red_knot_vendored/vendor/typeshed/source_commit.txt

@@ -1 +1 @@
-5052fa2f18db4493892e0f2775030683c9d06531
+0a2da01946a406ede42e9c66f416a7e7758991d6

crates/red_knot_vendored/vendor/typeshed/stdlib/VERSIONS

@@ -33,6 +33,7 @@ _contextvars: 3.7-
 _csv: 3.0-
 _ctypes: 3.0-
 _curses: 3.0-
+_curses_panel: 3.0-
 _dbm: 3.0-
 _decimal: 3.3-
 _dummy_thread: 3.0-3.8
@@ -40,6 +41,7 @@ _dummy_threading: 3.0-3.8
 _frozen_importlib: 3.0-
 _frozen_importlib_external: 3.5-
 _gdbm: 3.0-
+_hashlib: 3.0-
 _heapq: 3.0-
 _imp: 3.0-
 _interpchannels: 3.13-
@@ -52,6 +54,7 @@ _lsprof: 3.0-
 _lzma: 3.3-
 _markupbase: 3.0-
 _msi: 3.0-3.12
+_multibytecodec: 3.0-
 _operator: 3.4-
 _osx_support: 3.0-
 _posixsubprocess: 3.2-
@@ -139,6 +142,12 @@ doctest: 3.0-
 dummy_threading: 3.0-3.8
 email: 3.0-
 encodings: 3.0-
+encodings.cp1125: 3.4-
+encodings.cp273: 3.4-
+encodings.cp858: 3.2-
+encodings.koi8_t: 3.5-
+encodings.kz1048: 3.5-
+encodings.mac_centeuro: 3.0-3.8
 ensurepip: 3.0-
 enum: 3.4-
 errno: 3.0-

crates/red_knot_vendored/vendor/typeshed/stdlib/_codecs.pyi

@@ -2,10 +2,13 @@ import codecs
 import sys
 from _typeshed import ReadableBuffer
 from collections.abc import Callable
-from typing import Literal, overload
+from typing import Literal, final, overload, type_check_only
 from typing_extensions import TypeAlias
 
 # This type is not exposed; it is defined in unicodeobject.c
+# At runtime it calls itself builtins.EncodingMap
+@final
+@type_check_only
 class _EncodingMap:
     def size(self) -> int: ...
 

crates/red_knot_vendored/vendor/typeshed/stdlib/_collections_abc.pyi

@@ -73,6 +73,7 @@ _VT_co = TypeVar("_VT_co", covariant=True)  # Value type covariant containers.
 @final
 class dict_keys(KeysView[_KT_co], Generic[_KT_co, _VT_co]):  # undocumented
     def __eq__(self, value: object, /) -> bool: ...
+    def __reversed__(self) -> Iterator[_KT_co]: ...
     if sys.version_info >= (3, 13):
         def isdisjoint(self, other: Iterable[_KT_co], /) -> bool: ...
     if sys.version_info >= (3, 10):
@@ -81,6 +82,7 @@ class dict_keys(KeysView[_KT_co], Generic[_KT_co, _VT_co]):  # undocumented
 
 @final
 class dict_values(ValuesView[_VT_co], Generic[_KT_co, _VT_co]):  # undocumented
+    def __reversed__(self) -> Iterator[_VT_co]: ...
     if sys.version_info >= (3, 10):
         @property
         def mapping(self) -> MappingProxyType[_KT_co, _VT_co]: ...
@@ -88,6 +90,7 @@ class dict_values(ValuesView[_VT_co], Generic[_KT_co, _VT_co]):  # undocumented
 @final
 class dict_items(ItemsView[_KT_co, _VT_co]):  # undocumented
     def __eq__(self, value: object, /) -> bool: ...
+    def __reversed__(self) -> Iterator[tuple[_KT_co, _VT_co]]: ...
     if sys.version_info >= (3, 13):
         def isdisjoint(self, other: Iterable[tuple[_KT_co, _VT_co]], /) -> bool: ...
     if sys.version_info >= (3, 10):

crates/red_knot_vendored/vendor/typeshed/stdlib/_csv.pyi

@@ -1,9 +1,9 @@
 import csv
 import sys
 from _typeshed import SupportsWrite
-from collections.abc import Iterable, Iterator
-from typing import Any, Final
-from typing_extensions import TypeAlias
+from collections.abc import Iterable
+from typing import Any, Final, type_check_only
+from typing_extensions import Self, TypeAlias
 
 __version__: Final[str]
 
@@ -45,17 +45,47 @@ class Dialect:
         strict: bool = False,
     ) -> None: ...
 
-class _reader(Iterator[list[str]]):
-    @property
-    def dialect(self) -> Dialect: ...
-    line_num: int
-    def __next__(self) -> list[str]: ...
+if sys.version_info >= (3, 10):
+    # This class calls itself _csv.reader.
+    class Reader:
+        @property
+        def dialect(self) -> Dialect: ...
+        line_num: int
+        def __iter__(self) -> Self: ...
+        def __next__(self) -> list[str]: ...
 
-class _writer:
-    @property
-    def dialect(self) -> Dialect: ...
-    def writerow(self, row: Iterable[Any]) -> Any: ...
-    def writerows(self, rows: Iterable[Iterable[Any]]) -> None: ...
+    # This class calls itself _csv.writer.
+    class Writer:
+        @property
+        def dialect(self) -> Dialect: ...
+        if sys.version_info >= (3, 13):
+            def writerow(self, row: Iterable[Any], /) -> Any: ...
+            def writerows(self, rows: Iterable[Iterable[Any]], /) -> None: ...
+        else:
+            def writerow(self, row: Iterable[Any]) -> Any: ...
+            def writerows(self, rows: Iterable[Iterable[Any]]) -> None: ...
+
+    # For the return types below.
+    # These aliases can be removed when typeshed drops support for 3.9.
+    _reader = Reader
+    _writer = Writer
+else:
+    # This class is not exposed. It calls itself _csv.reader.
+    @type_check_only
+    class _reader:
+        @property
+        def dialect(self) -> Dialect: ...
+        line_num: int
+        def __iter__(self) -> Self: ...
+        def __next__(self) -> list[str]: ...
+
+    # This class is not exposed. It calls itself _csv.writer.
+    @type_check_only
+    class _writer:
+        @property
+        def dialect(self) -> Dialect: ...
+        def writerow(self, row: Iterable[Any]) -> Any: ...
+        def writerows(self, rows: Iterable[Iterable[Any]]) -> None: ...
 
 def writer(
     csvfile: SupportsWrite[str],

crates/red_knot_vendored/vendor/typeshed/stdlib/_ctypes.pyi

@@ -1,9 +1,10 @@
+import _typeshed
 import sys
-from _typeshed import ReadableBuffer, WriteableBuffer
+from _typeshed import ReadableBuffer, StrOrBytesPath, WriteableBuffer
 from abc import abstractmethod
 from collections.abc import Callable, Iterable, Iterator, Mapping, Sequence
 from ctypes import CDLL, ArgumentError as ArgumentError, c_void_p
-from typing import Any, ClassVar, Generic, TypeVar, overload
+from typing import Any, ClassVar, Generic, TypeVar, final, overload, type_check_only
 from typing_extensions import Self, TypeAlias
 
 if sys.version_info >= (3, 9):
@@ -47,46 +48,79 @@ if sys.platform == "win32":
     def LoadLibrary(name: str, load_flags: int = 0, /) -> int: ...
     def FreeLibrary(handle: int, /) -> None: ...
 
-class _CDataMeta(type):
-    # By default mypy complains about the following two methods, because strictly speaking cls
-    # might not be a Type[_CT]. However this can never actually happen, because the only class that
-    # uses _CDataMeta as its metaclass is _CData. So it's safe to ignore the errors here.
-    def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
-    def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+else:
+    def dlclose(handle: int, /) -> None: ...
+    # The default for flag is RTLD_GLOBAL|RTLD_LOCAL, which is platform dependent.
+    def dlopen(name: StrOrBytesPath, flag: int = ..., /) -> int: ...
+    def dlsym(handle: int, name: str, /) -> int: ...
 
-class _CData(metaclass=_CDataMeta):
+if sys.version_info >= (3, 13):
+    # This class is not exposed. It calls itself _ctypes.CType_Type.
+    @type_check_only
+    class _CType_Type(type):
+        # By default mypy complains about the following two methods, because strictly speaking cls
+        # might not be a Type[_CT]. However this doesn't happen because this is only a
+        # metaclass for subclasses of _CData.
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+    _CTypeBaseType = _CType_Type
+
+else:
+    _CTypeBaseType = type
+
+# This class is not exposed.
+@type_check_only
+class _CData:
     _b_base_: int
     _b_needsfree_: bool
     _objects: Mapping[Any, int] | None
-    # At runtime the following classmethods are available only on classes, not
-    # on instances. This can't be reflected properly in the type system:
-    #
-    # Structure.from_buffer(...)  # valid at runtime
-    # Structure(...).from_buffer(...)  # invalid at runtime
-    #
-    @classmethod
-    def from_buffer(cls, source: WriteableBuffer, offset: int = ...) -> Self: ...
-    @classmethod
-    def from_buffer_copy(cls, source: ReadableBuffer, offset: int = ...) -> Self: ...
-    @classmethod
-    def from_address(cls, address: int) -> Self: ...
-    @classmethod
-    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
-    @classmethod
-    def in_dll(cls, library: CDLL, name: str) -> Self: ...
     def __buffer__(self, flags: int, /) -> memoryview: ...
-    def __release_buffer__(self, buffer: memoryview, /) -> None: ...
+    def __ctypes_from_outparam__(self, /) -> Self: ...
 
-class _SimpleCData(_CData, Generic[_T]):
+# this is a union of all the subclasses of _CData, which is useful because of
+# the methods that are present on each of those subclasses which are not present
+# on _CData itself.
+_CDataType: TypeAlias = _SimpleCData[Any] | _Pointer[Any] | CFuncPtr | Union | Structure | Array[Any]
+
+# This class is not exposed. It calls itself _ctypes.PyCSimpleType.
+@type_check_only
+class _PyCSimpleType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(self: type[_CT], value: int, /) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(self: type[_CT], value: int, /) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+class _SimpleCData(_CData, Generic[_T], metaclass=_PyCSimpleType):
     value: _T
     # The TypeVar can be unsolved here,
     # but we can't use overloads without creating many, many mypy false-positive errors
     def __init__(self, value: _T = ...) -> None: ...  # pyright: ignore[reportInvalidTypeVarUse]
+    def __ctypes_from_outparam__(self, /) -> _T: ...  # type: ignore[override]
 
 class _CanCastTo(_CData): ...
 class _PointerLike(_CanCastTo): ...
 
-class _Pointer(_PointerLike, _CData, Generic[_CT]):
+# This type is not exposed. It calls itself _ctypes.PyCPointerType.
+@type_check_only
+class _PyCPointerType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    def set_type(self, type: Any, /) -> None: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+class _Pointer(_PointerLike, _CData, Generic[_CT], metaclass=_PyCPointerType):
     _type_: type[_CT]
     contents: _CT
     @overload
@@ -105,16 +139,32 @@ def POINTER(type: None, /) -> type[c_void_p]: ...
 def POINTER(type: type[_CT], /) -> type[_Pointer[_CT]]: ...
 def pointer(obj: _CT, /) -> _Pointer[_CT]: ...
 
+# This class is not exposed. It calls itself _ctypes.CArgObject.
+@final
+@type_check_only
 class _CArgObject: ...
 
-def byref(obj: _CData, offset: int = ...) -> _CArgObject: ...
+def byref(obj: _CData | _CDataType, offset: int = ...) -> _CArgObject: ...
 
-_ECT: TypeAlias = Callable[[_CData | None, CFuncPtr, tuple[_CData, ...]], _CData]
+_ECT: TypeAlias = Callable[[_CData | _CDataType | None, CFuncPtr, tuple[_CData | _CDataType, ...]], _CDataType]
 _PF: TypeAlias = tuple[int] | tuple[int, str | None] | tuple[int, str | None, Any]
 
-class CFuncPtr(_PointerLike, _CData):
-    restype: type[_CData] | Callable[[int], Any] | None
-    argtypes: Sequence[type[_CData]]
+# This class is not exposed. It calls itself _ctypes.PyCFuncPtrType.
+@type_check_only
+class _PyCFuncPtrType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+class CFuncPtr(_PointerLike, _CData, metaclass=_PyCFuncPtrType):
+    restype: type[_CDataType] | Callable[[int], Any] | None
+    argtypes: Sequence[type[_CDataType]]
     errcheck: _ECT
     # Abstract attribute that must be defined on subclasses
     _flags_: ClassVar[int]
@@ -129,7 +179,7 @@ class CFuncPtr(_PointerLike, _CData):
     if sys.platform == "win32":
         @overload
         def __init__(
-            self, vtbl_index: int, name: str, paramflags: tuple[_PF, ...] | None = ..., iid: _CData | None = ..., /
+            self, vtbl_index: int, name: str, paramflags: tuple[_PF, ...] | None = ..., iid: _CData | _CDataType | None = ..., /
         ) -> None: ...
 
     def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
@@ -137,30 +187,95 @@ class CFuncPtr(_PointerLike, _CData):
 _GetT = TypeVar("_GetT")
 _SetT = TypeVar("_SetT")
 
+# This class is not exposed. It calls itself _ctypes.CField.
+@final
+@type_check_only
 class _CField(Generic[_CT, _GetT, _SetT]):
     offset: int
     size: int
-    @overload
-    def __get__(self, instance: None, owner: type[Any] | None, /) -> Self: ...
-    @overload
-    def __get__(self, instance: Any, owner: type[Any] | None, /) -> _GetT: ...
+    if sys.version_info >= (3, 10):
+        @overload
+        def __get__(self, instance: None, owner: type[Any] | None = None, /) -> Self: ...
+        @overload
+        def __get__(self, instance: Any, owner: type[Any] | None = None, /) -> _GetT: ...
+    else:
+        @overload
+        def __get__(self, instance: None, owner: type[Any] | None, /) -> Self: ...
+        @overload
+        def __get__(self, instance: Any, owner: type[Any] | None, /) -> _GetT: ...
+
     def __set__(self, instance: Any, value: _SetT, /) -> None: ...
 
-class _StructUnionMeta(_CDataMeta):
-    _fields_: Sequence[tuple[str, type[_CData]] | tuple[str, type[_CData], int]]
-    _pack_: int
-    _anonymous_: Sequence[str]
+# This class is not exposed. It calls itself _ctypes.UnionType.
+@type_check_only
+class _UnionType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    # At runtime, various attributes are created on a Union subclass based
+    # on its _fields_. This method doesn't exist, but represents those
+    # dynamically created attributes.
     def __getattr__(self, name: str) -> _CField[Any, Any, Any]: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+class Union(_CData, metaclass=_UnionType):
+    _fields_: ClassVar[Sequence[tuple[str, type[_CDataType]] | tuple[str, type[_CDataType], int]]]
+    _pack_: ClassVar[int]
+    _anonymous_: ClassVar[Sequence[str]]
+    if sys.version_info >= (3, 13):
+        _align_: ClassVar[int]
 
-class _StructUnionBase(_CData, metaclass=_StructUnionMeta):
     def __init__(self, *args: Any, **kw: Any) -> None: ...
     def __getattr__(self, name: str) -> Any: ...
     def __setattr__(self, name: str, value: Any) -> None: ...
 
-class Union(_StructUnionBase): ...
-class Structure(_StructUnionBase): ...
+# This class is not exposed. It calls itself _ctypes.PyCStructType.
+@type_check_only
+class _PyCStructType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    # At runtime, various attributes are created on a Structure subclass based
+    # on its _fields_. This method doesn't exist, but represents those
+    # dynamically created attributes.
+    def __getattr__(self, name: str) -> _CField[Any, Any, Any]: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
 
-class Array(_CData, Generic[_CT]):
+class Structure(_CData, metaclass=_PyCStructType):
+    _fields_: ClassVar[Sequence[tuple[str, type[_CDataType]] | tuple[str, type[_CDataType], int]]]
+    _pack_: ClassVar[int]
+    _anonymous_: ClassVar[Sequence[str]]
+    if sys.version_info >= (3, 13):
+        _align_: ClassVar[int]
+
+    def __init__(self, *args: Any, **kw: Any) -> None: ...
+    def __getattr__(self, name: str) -> Any: ...
+    def __setattr__(self, name: str, value: Any) -> None: ...
+
+# This class is not exposed. It calls itself _ctypes.PyCArrayType.
+@type_check_only
+class _PyCArrayType(_CTypeBaseType):
+    def from_address(self: type[_typeshed.Self], value: int, /) -> _typeshed.Self: ...
+    def from_buffer(self: type[_typeshed.Self], obj: WriteableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_buffer_copy(self: type[_typeshed.Self], buffer: ReadableBuffer, offset: int = 0, /) -> _typeshed.Self: ...
+    def from_param(self: type[_typeshed.Self], value: Any, /) -> _typeshed.Self | _CArgObject: ...
+    def in_dll(self: type[_typeshed.Self], dll: CDLL, name: str, /) -> _typeshed.Self: ...
+    if sys.version_info < (3, 13):
+        # Inherited from CType_Type starting on 3.13
+        def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+        def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc] # pyright: ignore[reportGeneralTypeIssues]
+
+class Array(_CData, Generic[_CT], metaclass=_PyCArrayType):
     @property
     @abstractmethod
     def _length_(self) -> int: ...
@@ -205,9 +320,15 @@ class Array(_CData, Generic[_CT]):
     if sys.version_info >= (3, 9):
         def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
-def addressof(obj: _CData, /) -> int: ...
-def alignment(obj_or_type: _CData | type[_CData], /) -> int: ...
+def addressof(obj: _CData | _CDataType, /) -> int: ...
+def alignment(obj_or_type: _CData | _CDataType | type[_CData | _CDataType], /) -> int: ...
 def get_errno() -> int: ...
-def resize(obj: _CData, size: int, /) -> None: ...
+def resize(obj: _CData | _CDataType, size: int, /) -> None: ...
 def set_errno(value: int, /) -> int: ...
-def sizeof(obj_or_type: _CData | type[_CData], /) -> int: ...
+def sizeof(obj_or_type: _CData | _CDataType | type[_CData | _CDataType], /) -> int: ...
+def PyObj_FromPtr(address: int, /) -> Any: ...
+def Py_DECREF(o: _T, /) -> _T: ...
+def Py_INCREF(o: _T, /) -> _T: ...
+def buffer_info(o: _CData | _CDataType | type[_CData | _CDataType], /) -> tuple[str, int, tuple[int, ...]]: ...
+def call_cdeclfunction(address: int, arguments: tuple[Any, ...], /) -> Any: ...
+def call_function(address: int, arguments: tuple[Any, ...], /) -> Any: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/_curses.pyi

@@ -1,6 +1,7 @@
 import sys
 from _typeshed import ReadOnlyBuffer, SupportsRead
-from typing import IO, Any, NamedTuple, final, overload
+from curses import _ncurses_version
+from typing import IO, Any, final, overload
 from typing_extensions import TypeAlias
 
 # NOTE: This module is ordinarily only available on Unix, but the windows-curses
@@ -549,9 +550,4 @@ class window:  # undocumented
     @overload
     def vline(self, y: int, x: int, ch: _ChType, n: int) -> None: ...
 
-class _ncurses_version(NamedTuple):
-    major: int
-    minor: int
-    patch: int
-
 ncurses_version: _ncurses_version

crates/red_knot_vendored/vendor/typeshed/stdlib/_curses_panel.pyi

@@ -0,0 +1,27 @@
+from _curses import window
+from typing import final
+
+__version__: str
+version: str
+
+class error(Exception): ...
+
+@final
+class panel:
+    def above(self) -> panel: ...
+    def below(self) -> panel: ...
+    def bottom(self) -> None: ...
+    def hidden(self) -> bool: ...
+    def hide(self) -> None: ...
+    def move(self, y: int, x: int, /) -> None: ...
+    def replace(self, win: window, /) -> None: ...
+    def set_userptr(self, obj: object, /) -> None: ...
+    def show(self) -> None: ...
+    def top(self) -> None: ...
+    def userptr(self) -> object: ...
+    def window(self) -> window: ...
+
+def bottom_panel() -> panel: ...
+def new_panel(win: window, /) -> panel: ...
+def top_panel() -> panel: ...
+def update_panels() -> panel: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/_dbm.pyi

@@ -1,7 +1,7 @@
 import sys
 from _typeshed import ReadOnlyBuffer, StrOrBytesPath
 from types import TracebackType
-from typing import TypeVar, overload
+from typing import TypeVar, final, overload, type_check_only
 from typing_extensions import Self, TypeAlias
 
 if sys.platform != "win32":
@@ -13,6 +13,8 @@ if sys.platform != "win32":
     library: str
 
     # Actual typename dbm, not exposed by the implementation
+    @final
+    @type_check_only
     class _dbm:
         def close(self) -> None: ...
         if sys.version_info >= (3, 13):
@@ -22,18 +24,17 @@ if sys.platform != "win32":
         def __setitem__(self, key: _KeyType, value: _ValueType) -> None: ...
         def __delitem__(self, key: _KeyType) -> None: ...
         def __len__(self) -> int: ...
-        def __del__(self) -> None: ...
         def __enter__(self) -> Self: ...
         def __exit__(
             self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: TracebackType | None
         ) -> None: ...
         @overload
-        def get(self, k: _KeyType) -> bytes | None: ...
+        def get(self, k: _KeyType, /) -> bytes | None: ...
         @overload
-        def get(self, k: _KeyType, default: _T) -> bytes | _T: ...
+        def get(self, k: _KeyType, default: _T, /) -> bytes | _T: ...
         def keys(self) -> list[bytes]: ...
-        def setdefault(self, k: _KeyType, default: _ValueType = ...) -> bytes: ...
-        # Don't exist at runtime
+        def setdefault(self, k: _KeyType, default: _ValueType = ..., /) -> bytes: ...
+        # This isn't true, but the class can't be instantiated. See #13024
         __new__: None  # type: ignore[assignment]
         __init__: None  # type: ignore[assignment]
 

crates/red_knot_vendored/vendor/typeshed/stdlib/_decimal.pyi

@@ -17,20 +17,13 @@ from decimal import (
     Rounded as Rounded,
     Subnormal as Subnormal,
     Underflow as Underflow,
+    _ContextManager,
 )
-from types import TracebackType
 from typing import Final
 from typing_extensions import TypeAlias
 
 _TrapType: TypeAlias = type[DecimalException]
 
-class _ContextManager:
-    new_context: Context
-    saved_context: Context
-    def __init__(self, new_context: Context) -> None: ...
-    def __enter__(self) -> Context: ...
-    def __exit__(self, t: type[BaseException] | None, v: BaseException | None, tb: TracebackType | None) -> None: ...
-
 __version__: Final[str]
 __libmpdec_version__: Final[str]
 

crates/red_knot_vendored/vendor/typeshed/stdlib/_hashlib.pyi

@@ -0,0 +1,80 @@
+import sys
+from _typeshed import ReadableBuffer
+from collections.abc import Callable
+from types import ModuleType
+from typing import AnyStr, final, overload
+from typing_extensions import Self, TypeAlias
+
+_DigestMod: TypeAlias = str | Callable[[], HASH] | ModuleType | None
+
+openssl_md_meth_names: frozenset[str]
+
+class HASH:
+    @property
+    def digest_size(self) -> int: ...
+    @property
+    def block_size(self) -> int: ...
+    @property
+    def name(self) -> str: ...
+    def copy(self) -> Self: ...
+    def digest(self) -> bytes: ...
+    def hexdigest(self) -> str: ...
+    def update(self, obj: ReadableBuffer, /) -> None: ...
+
+if sys.version_info >= (3, 10):
+    class UnsupportedDigestmodError(ValueError): ...
+
+if sys.version_info >= (3, 9):
+    class HASHXOF(HASH):
+        def digest(self, length: int) -> bytes: ...  # type: ignore[override]
+        def hexdigest(self, length: int) -> str: ...  # type: ignore[override]
+
+    @final
+    class HMAC:
+        @property
+        def digest_size(self) -> int: ...
+        @property
+        def block_size(self) -> int: ...
+        @property
+        def name(self) -> str: ...
+        def copy(self) -> Self: ...
+        def digest(self) -> bytes: ...
+        def hexdigest(self) -> str: ...
+        def update(self, msg: ReadableBuffer) -> None: ...
+
+    @overload
+    def compare_digest(a: ReadableBuffer, b: ReadableBuffer, /) -> bool: ...
+    @overload
+    def compare_digest(a: AnyStr, b: AnyStr, /) -> bool: ...
+    def get_fips_mode() -> int: ...
+    def hmac_new(key: bytes | bytearray, msg: ReadableBuffer = b"", digestmod: _DigestMod = None) -> HMAC: ...
+    def new(name: str, string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_md5(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha1(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha224(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha256(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha384(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha512(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha3_224(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha3_256(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha3_384(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_sha3_512(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASH: ...
+    def openssl_shake_128(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASHXOF: ...
+    def openssl_shake_256(string: ReadableBuffer = b"", *, usedforsecurity: bool = True) -> HASHXOF: ...
+
+else:
+    def new(name: str, string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_md5(string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_sha1(string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_sha224(string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_sha256(string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_sha384(string: ReadableBuffer = b"") -> HASH: ...
+    def openssl_sha512(string: ReadableBuffer = b"") -> HASH: ...
+
+def hmac_digest(key: bytes | bytearray, msg: ReadableBuffer, digest: str) -> bytes: ...
+def pbkdf2_hmac(
+    hash_name: str, password: ReadableBuffer, salt: ReadableBuffer, iterations: int, dklen: int | None = None
+) -> bytes: ...
+def scrypt(
+    password: ReadableBuffer, *, salt: ReadableBuffer, n: int, r: int, p: int, maxmem: int = 0, dklen: int = 64
+) -> bytes: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/_json.pyi

@@ -45,5 +45,6 @@ class make_scanner:
     def __init__(self, context: make_scanner) -> None: ...
     def __call__(self, string: str, index: int) -> tuple[Any, int]: ...
 
+def encode_basestring(s: str, /) -> str: ...
 def encode_basestring_ascii(s: str, /) -> str: ...
 def scanstring(string: str, end: int, strict: bool = ...) -> tuple[str, int]: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/_multibytecodec.pyi

@@ -0,0 +1,44 @@
+from _typeshed import ReadableBuffer
+from codecs import _ReadableStream, _WritableStream
+from collections.abc import Iterable
+from typing import final, type_check_only
+
+# This class is not exposed. It calls itself _multibytecodec.MultibyteCodec.
+@final
+@type_check_only
+class _MultibyteCodec:
+    def decode(self, input: ReadableBuffer, errors: str | None = None) -> str: ...
+    def encode(self, input: str, errors: str | None = None) -> bytes: ...
+
+class MultibyteIncrementalDecoder:
+    errors: str
+    def __init__(self, errors: str = "strict") -> None: ...
+    def decode(self, input: ReadableBuffer, final: bool = False) -> str: ...
+    def getstate(self) -> tuple[bytes, int]: ...
+    def reset(self) -> None: ...
+    def setstate(self, state: tuple[bytes, int], /) -> None: ...
+
+class MultibyteIncrementalEncoder:
+    errors: str
+    def __init__(self, errors: str = "strict") -> None: ...
+    def encode(self, input: str, final: bool = False) -> bytes: ...
+    def getstate(self) -> int: ...
+    def reset(self) -> None: ...
+    def setstate(self, state: int, /) -> None: ...
+
+class MultibyteStreamReader:
+    errors: str
+    stream: _ReadableStream
+    def __init__(self, stream: _ReadableStream, errors: str = "strict") -> None: ...
+    def read(self, sizeobj: int | None = None, /) -> str: ...
+    def readline(self, sizeobj: int | None = None, /) -> str: ...
+    def readlines(self, sizehintobj: int | None = None, /) -> list[str]: ...
+    def reset(self) -> None: ...
+
+class MultibyteStreamWriter:
+    errors: str
+    stream: _WritableStream
+    def __init__(self, stream: _WritableStream, errors: str = "strict") -> None: ...
+    def reset(self) -> None: ...
+    def write(self, strobj: str, /) -> None: ...
+    def writelines(self, lines: Iterable[str], /) -> None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/_posixsubprocess.pyi

@@ -4,7 +4,6 @@ from collections.abc import Callable, Sequence
 from typing import SupportsIndex
 
 if sys.platform != "win32":
-    def cloexec_pipe() -> tuple[int, int]: ...
     def fork_exec(
         args: Sequence[StrOrBytesPath] | None,
         executable_list: Sequence[bytes],

crates/red_knot_vendored/vendor/typeshed/stdlib/_socket.pyi

@@ -3,7 +3,7 @@ from _typeshed import ReadableBuffer, WriteableBuffer
 from collections.abc import Iterable
 from socket import error as error, gaierror as gaierror, herror as herror, timeout as timeout
 from typing import Any, SupportsIndex, overload
-from typing_extensions import TypeAlias
+from typing_extensions import CapsuleType, TypeAlias
 
 _CMSG: TypeAlias = tuple[int, int, bytes]
 _CMSGArg: TypeAlias = tuple[int, int, ReadableBuffer]
@@ -72,7 +72,8 @@ SO_SNDBUF: int
 SO_SNDLOWAT: int
 SO_SNDTIMEO: int
 SO_TYPE: int
-SO_USELOOPBACK: int
+if sys.platform != "linux":
+    SO_USELOOPBACK: int
 if sys.platform == "win32":
     SO_EXCLUSIVEADDRUSE: int
 if sys.platform != "win32":
@@ -87,7 +88,10 @@ if sys.platform != "win32" and sys.platform != "darwin":
     SO_PEERSEC: int
     SO_PRIORITY: int
     SO_PROTOCOL: int
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
     SO_SETFIB: int
+if sys.platform == "linux" and sys.version_info >= (3, 13):
+    SO_BINDTOIFINDEX: int
 
 SOMAXCONN: int
 
@@ -99,27 +103,32 @@ MSG_TRUNC: int
 MSG_WAITALL: int
 if sys.platform != "win32":
     MSG_DONTWAIT: int
-    MSG_EOF: int
     MSG_EOR: int
     MSG_NOSIGNAL: int  # Sometimes this exists on darwin, sometimes not
 if sys.platform != "darwin":
-    MSG_BCAST: int
     MSG_ERRQUEUE: int
+if sys.platform == "win32":
+    MSG_BCAST: int
     MSG_MCAST: int
 if sys.platform != "win32" and sys.platform != "darwin":
-    MSG_BTAG: int
     MSG_CMSG_CLOEXEC: int
     MSG_CONFIRM: int
-    MSG_ETAG: int
     MSG_FASTOPEN: int
     MSG_MORE: int
+if sys.platform != "win32" and sys.platform != "linux":
+    MSG_EOF: int
+if sys.platform != "win32" and sys.platform != "linux" and sys.platform != "darwin":
     MSG_NOTIFICATION: int
+    MSG_BTAG: int  # Not FreeBSD either
+    MSG_ETAG: int  # Not FreeBSD either
 
 SOL_IP: int
 SOL_SOCKET: int
 SOL_TCP: int
 SOL_UDP: int
 if sys.platform != "win32" and sys.platform != "darwin":
+    # Defined in socket.h for Linux, but these aren't always present for
+    # some reason.
     SOL_ATALK: int
     SOL_AX25: int
     SOL_HCI: int
@@ -128,10 +137,11 @@ if sys.platform != "win32" and sys.platform != "darwin":
     SOL_ROSE: int
 
 if sys.platform != "win32":
-    SCM_CREDS: int
     SCM_RIGHTS: int
 if sys.platform != "win32" and sys.platform != "darwin":
     SCM_CREDENTIALS: int
+if sys.platform != "win32" and sys.platform != "linux":
+    SCM_CREDS: int
 
 IPPROTO_ICMP: int
 IPPROTO_IP: int
@@ -143,21 +153,22 @@ IPPROTO_DSTOPTS: int
 IPPROTO_EGP: int
 IPPROTO_ESP: int
 IPPROTO_FRAGMENT: int
-IPPROTO_GGP: int
 IPPROTO_HOPOPTS: int
 IPPROTO_ICMPV6: int
 IPPROTO_IDP: int
 IPPROTO_IGMP: int
-IPPROTO_IPV4: int
 IPPROTO_IPV6: int
-IPPROTO_MAX: int
-IPPROTO_ND: int
 IPPROTO_NONE: int
 IPPROTO_PIM: int
 IPPROTO_PUP: int
 IPPROTO_ROUTING: int
 IPPROTO_SCTP: int
-if sys.platform != "darwin":
+if sys.platform != "linux":
+    IPPROTO_GGP: int
+    IPPROTO_IPV4: int
+    IPPROTO_MAX: int
+    IPPROTO_ND: int
+if sys.platform == "win32":
     IPPROTO_CBT: int
     IPPROTO_ICLFXBM: int
     IPPROTO_IGP: int
@@ -166,18 +177,19 @@ if sys.platform != "darwin":
     IPPROTO_RDP: int
     IPPROTO_ST: int
 if sys.platform != "win32":
-    IPPROTO_EON: int
     IPPROTO_GRE: int
-    IPPROTO_HELLO: int
-    IPPROTO_IPCOMP: int
     IPPROTO_IPIP: int
     IPPROTO_RSVP: int
     IPPROTO_TP: int
+if sys.platform != "win32" and sys.platform != "linux":
+    IPPROTO_EON: int
+    IPPROTO_HELLO: int
+    IPPROTO_IPCOMP: int
     IPPROTO_XTP: int
-if sys.platform != "win32" and sys.platform != "darwin":
-    IPPROTO_BIP: int
-    IPPROTO_MOBILE: int
-    IPPROTO_VRRP: int
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
+    IPPROTO_BIP: int  # Not FreeBSD either
+    IPPROTO_MOBILE: int  # Not FreeBSD either
+    IPPROTO_VRRP: int  # Not FreeBSD either
 if sys.version_info >= (3, 9) and sys.platform == "linux":
     # Availability: Linux >= 2.6.20, FreeBSD >= 10.1
     IPPROTO_UDPLITE: int
@@ -202,11 +214,10 @@ IP_MULTICAST_IF: int
 IP_MULTICAST_LOOP: int
 IP_MULTICAST_TTL: int
 IP_OPTIONS: int
-IP_RECVDSTADDR: int
+if sys.platform != "linux":
+    IP_RECVDSTADDR: int
 if sys.version_info >= (3, 10):
     IP_RECVTOS: int
-elif sys.platform != "win32" and sys.platform != "darwin":
-    IP_RECVTOS: int
 IP_TOS: int
 IP_TTL: int
 if sys.platform != "win32":
@@ -218,6 +229,7 @@ if sys.platform != "win32":
     IP_RETOPTS: int
 if sys.platform != "win32" and sys.platform != "darwin":
     IP_TRANSPARENT: int
+if sys.platform != "win32" and sys.platform != "darwin" and sys.version_info >= (3, 11):
     IP_BIND_ADDRESS_NO_PORT: int
 if sys.version_info >= (3, 12):
     IP_ADD_SOURCE_MEMBERSHIP: int
@@ -255,6 +267,9 @@ if sys.platform != "win32":
         IPV6_RECVPATHMTU: int
         IPV6_RECVPKTINFO: int
         IPV6_RTHDRDSTOPTS: int
+
+if sys.platform != "win32" and sys.platform != "linux":
+    if sys.version_info >= (3, 9) or sys.platform != "darwin":
         IPV6_USE_MIN_MTU: int
 
 EAI_AGAIN: int
@@ -268,11 +283,12 @@ EAI_SERVICE: int
 EAI_SOCKTYPE: int
 if sys.platform != "win32":
     EAI_ADDRFAMILY: int
+    EAI_OVERFLOW: int
+    EAI_SYSTEM: int
+if sys.platform != "win32" and sys.platform != "linux":
     EAI_BADHINTS: int
     EAI_MAX: int
-    EAI_OVERFLOW: int
     EAI_PROTOCOL: int
-    EAI_SYSTEM: int
 
 AI_ADDRCONFIG: int
 AI_ALL: int
@@ -281,7 +297,7 @@ AI_NUMERICHOST: int
 AI_NUMERICSERV: int
 AI_PASSIVE: int
 AI_V4MAPPED: int
-if sys.platform != "win32":
+if sys.platform != "win32" and sys.platform != "linux":
     AI_DEFAULT: int
     AI_MASK: int
     AI_V4MAPPED_CFG: int
@@ -293,6 +309,8 @@ NI_NAMEREQD: int
 NI_NOFQDN: int
 NI_NUMERICHOST: int
 NI_NUMERICSERV: int
+if sys.platform == "linux" and sys.version_info >= (3, 13):
+    NI_IDN: int
 
 TCP_FASTOPEN: int
 TCP_KEEPCNT: int
@@ -318,6 +336,27 @@ if sys.platform != "win32" and sys.platform != "darwin":
     TCP_SYNCNT: int
     TCP_USER_TIMEOUT: int
     TCP_WINDOW_CLAMP: int
+if sys.platform == "linux" and sys.version_info >= (3, 12):
+    TCP_CC_INFO: int
+    TCP_FASTOPEN_CONNECT: int
+    TCP_FASTOPEN_KEY: int
+    TCP_FASTOPEN_NO_COOKIE: int
+    TCP_INQ: int
+    TCP_MD5SIG: int
+    TCP_MD5SIG_EXT: int
+    TCP_QUEUE_SEQ: int
+    TCP_REPAIR: int
+    TCP_REPAIR_OPTIONS: int
+    TCP_REPAIR_QUEUE: int
+    TCP_REPAIR_WINDOW: int
+    TCP_SAVED_SYN: int
+    TCP_SAVE_SYN: int
+    TCP_THIN_DUPACK: int
+    TCP_THIN_LINEAR_TIMEOUTS: int
+    TCP_TIMESTAMP: int
+    TCP_TX_DELAY: int
+    TCP_ULP: int
+    TCP_ZEROCOPY_RECEIVE: int
 
 # --------------------
 # Specifically documented constants
@@ -334,12 +373,13 @@ if sys.platform == "linux":
     CAN_ERR_FLAG: int
     CAN_ERR_MASK: int
     CAN_RAW: int
-    CAN_RAW_ERR_FILTER: int
     CAN_RAW_FILTER: int
     CAN_RAW_LOOPBACK: int
     CAN_RAW_RECV_OWN_MSGS: int
     CAN_RTR_FLAG: int
     CAN_SFF_MASK: int
+    if sys.version_info < (3, 11):
+        CAN_RAW_ERR_FILTER: int
 
 if sys.platform == "linux":
     # Availability: Linux >= 2.6.25
@@ -437,12 +477,13 @@ if sys.platform == "linux":
     AF_RDS: int
     PF_RDS: int
     SOL_RDS: int
+    # These are present in include/linux/rds.h but don't always show up
+    # here.
     RDS_CANCEL_SENT_TO: int
     RDS_CMSG_RDMA_ARGS: int
     RDS_CMSG_RDMA_DEST: int
     RDS_CMSG_RDMA_MAP: int
     RDS_CMSG_RDMA_STATUS: int
-    RDS_CMSG_RDMA_UPDATE: int
     RDS_CONG_MONITOR: int
     RDS_FREE_MR: int
     RDS_GET_MR: int
@@ -456,6 +497,10 @@ if sys.platform == "linux":
     RDS_RDMA_USE_ONCE: int
     RDS_RECVERR: int
 
+    # This is supported by CPython but doesn't seem to be a real thing.
+    # The closest existing constant in rds.h is RDS_CMSG_CONG_UPDATE
+    # RDS_CMSG_RDMA_UPDATE: int
+
 if sys.platform == "win32":
     SIO_RCVALL: int
     SIO_KEEPALIVE_VALS: int
@@ -522,16 +567,17 @@ if sys.platform == "linux":
 if sys.platform != "win32" or sys.version_info >= (3, 9):
     # Documented as only available on BSD, macOS, but empirically sometimes
     # available on Windows
-    AF_LINK: int
+    if sys.platform != "linux":
+        AF_LINK: int
 
 has_ipv6: bool
 
-if sys.platform != "darwin":
+if sys.platform != "darwin" and sys.platform != "linux":
     if sys.platform != "win32" or sys.version_info >= (3, 9):
         BDADDR_ANY: str
         BDADDR_LOCAL: str
 
-if sys.platform != "win32" and sys.platform != "darwin":
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
     HCI_FILTER: int  # not in NetBSD or DragonFlyBSD
     HCI_TIME_STAMP: int  # not in FreeBSD, NetBSD, or DragonFlyBSD
     HCI_DATA_DIR: int  # not in FreeBSD, NetBSD, or DragonFlyBSD
@@ -580,36 +626,37 @@ if sys.version_info >= (3, 12):
 if sys.platform == "linux":
     # Netlink is defined by Linux
     AF_NETLINK: int
-    NETLINK_ARPD: int
     NETLINK_CRYPTO: int
     NETLINK_DNRTMSG: int
     NETLINK_FIREWALL: int
     NETLINK_IP6_FW: int
     NETLINK_NFLOG: int
-    NETLINK_ROUTE6: int
     NETLINK_ROUTE: int
-    NETLINK_SKIP: int
-    NETLINK_TAPBASE: int
-    NETLINK_TCPDIAG: int
     NETLINK_USERSOCK: int
-    NETLINK_W1: int
     NETLINK_XFRM: int
+    # Technically still supported by CPython
+    # NETLINK_ARPD: int  # linux 2.0 to 2.6.12 (EOL August 2005)
+    # NETLINK_ROUTE6: int  # linux 2.2 to 2.6.12 (EOL August 2005)
+    # NETLINK_SKIP: int  # linux 2.0 to 2.6.12 (EOL August 2005)
+    # NETLINK_TAPBASE: int  # linux 2.2 to 2.6.12 (EOL August 2005)
+    # NETLINK_TCPDIAG: int  # linux 2.6.0 to 2.6.13 (EOL December 2005)
+    # NETLINK_W1: int  # linux 2.6.13 to 2.6.17 (EOL October 2006)
 
 if sys.platform == "darwin":
     PF_SYSTEM: int
     SYSPROTO_CONTROL: int
 
-if sys.platform != "darwin":
+if sys.platform != "darwin" and sys.platform != "linux":
     if sys.version_info >= (3, 9) or sys.platform != "win32":
         AF_BLUETOOTH: int
 
-if sys.platform != "win32" and sys.platform != "darwin":
+if sys.platform != "win32" and sys.platform != "darwin" and sys.platform != "linux":
     # Linux and some BSD support is explicit in the docs
     # Windows and macOS do not support in practice
     BTPROTO_HCI: int
     BTPROTO_L2CAP: int
     BTPROTO_SCO: int  # not in FreeBSD
-if sys.platform != "darwin":
+if sys.platform != "darwin" and sys.platform != "linux":
     if sys.version_info >= (3, 9) or sys.platform != "win32":
         BTPROTO_RFCOMM: int
 
@@ -636,13 +683,14 @@ AF_SNA: int
 
 if sys.platform != "win32":
     AF_ROUTE: int
+
+if sys.platform == "darwin":
     AF_SYSTEM: int
 
 if sys.platform != "darwin":
     AF_IRDA: int
 
 if sys.platform != "win32" and sys.platform != "darwin":
-    AF_AAL5: int
     AF_ASH: int
     AF_ATMPVC: int
     AF_ATMSVC: int
@@ -661,10 +709,12 @@ if sys.platform != "win32" and sys.platform != "darwin":
 
 # Miscellaneous undocumented
 
-if sys.platform != "win32":
+if sys.platform != "win32" and sys.platform != "linux":
     LOCAL_PEERCRED: int
 
 if sys.platform != "win32" and sys.platform != "darwin":
+    # Defined in linux socket.h, but this isn't always present for
+    # some reason.
     IPX_TYPE: int
 
 # ===== Classes =====
@@ -792,4 +842,4 @@ def if_nameindex() -> list[tuple[int, str]]: ...
 def if_nametoindex(oname: str, /) -> int: ...
 def if_indextoname(index: int, /) -> str: ...
 
-CAPI: object
+CAPI: CapsuleType

crates/red_knot_vendored/vendor/typeshed/stdlib/_thread.pyi

@@ -44,6 +44,12 @@ def start_new_thread(function: Callable[[Unpack[_Ts]], object], args: tuple[Unpa
 @overload
 def start_new_thread(function: Callable[..., object], args: tuple[Any, ...], kwargs: dict[str, Any], /) -> int: ...
 
+# Obsolete synonym for start_new_thread()
+@overload
+def start_new(function: Callable[[Unpack[_Ts]], object], args: tuple[Unpack[_Ts]], /) -> int: ...
+@overload
+def start_new(function: Callable[..., object], args: tuple[Any, ...], kwargs: dict[str, Any], /) -> int: ...
+
 if sys.version_info >= (3, 10):
     def interrupt_main(signum: signal.Signals = ..., /) -> None: ...
 
@@ -51,7 +57,9 @@ else:
     def interrupt_main() -> None: ...
 
 def exit() -> NoReturn: ...
+def exit_thread() -> NoReturn: ...  # Obsolete synonym for exit()
 def allocate_lock() -> LockType: ...
+def allocate() -> LockType: ...  # Obsolete synonym for allocate_lock()
 def get_ident() -> int: ...
 def stack_size(size: int = 0, /) -> int: ...
 

crates/red_knot_vendored/vendor/typeshed/stdlib/_threading_local.pyi

@@ -1,3 +1,4 @@
+from threading import RLock
 from typing import Any
 from typing_extensions import Self, TypeAlias
 from weakref import ReferenceType
@@ -8,6 +9,9 @@ _LocalDict: TypeAlias = dict[Any, Any]
 class _localimpl:
     key: str
     dicts: dict[int, tuple[ReferenceType[Any], _LocalDict]]
+    # Keep localargs in sync with the *args, **kwargs annotation on local.__new__
+    localargs: tuple[list[Any], dict[str, Any]]
+    locallock: RLock
     def get_dict(self) -> _LocalDict: ...
     def create_dict(self) -> _LocalDict: ...
 

crates/red_knot_vendored/vendor/typeshed/stdlib/builtins.pyi

@@ -107,7 +107,7 @@ class object:
     @property
     def __class__(self) -> type[Self]: ...
     @__class__.setter
-    def __class__(self, type: type[object], /) -> None: ...
+    def __class__(self, type: type[Self], /) -> None: ...
     def __init__(self) -> None: ...
     def __new__(cls) -> Self: ...
     # N.B. `object.__setattr__` and `object.__delattr__` are heavily special-cased by type checkers.
@@ -1963,14 +1963,33 @@ class StopAsyncIteration(Exception):
 
 class SyntaxError(Exception):
     msg: str
+    filename: str | None
     lineno: int | None
     offset: int | None
     text: str | None
-    filename: str | None
+    # Errors are displayed differently if this attribute exists on the exception.
+    # The value is always None.
+    print_file_and_line: None
     if sys.version_info >= (3, 10):
         end_lineno: int | None
         end_offset: int | None
 
+    @overload
+    def __init__(self) -> None: ...
+    @overload
+    def __init__(self, msg: object, /) -> None: ...
+    # Second argument is the tuple (filename, lineno, offset, text)
+    @overload
+    def __init__(self, msg: str, info: tuple[str | None, int | None, int | None, str | None], /) -> None: ...
+    if sys.version_info >= (3, 10):
+        # end_lineno and end_offset must both be provided if one is.
+        @overload
+        def __init__(
+            self, msg: str, info: tuple[str | None, int | None, int | None, str | None, int | None, int | None], /
+        ) -> None: ...
+    # If you provide more than two arguments, it still creates the SyntaxError, but
+    # the arguments from the info tuple are not parsed. This form is omitted.
+
 class SystemError(Exception): ...
 class TypeError(Exception): ...
 class ValueError(Exception): ...

crates/red_knot_vendored/vendor/typeshed/stdlib/bz2.pyi

@@ -126,6 +126,7 @@ class BZ2File(BaseStream, IO[bytes]):
     def readline(self, size: SupportsIndex = -1) -> bytes: ...  # type: ignore[override]
     def readinto(self, b: WriteableBuffer) -> int: ...
     def readlines(self, size: SupportsIndex = -1) -> list[bytes]: ...
+    def peek(self, n: int = 0) -> bytes: ...
     def seek(self, offset: int, whence: int = 0) -> int: ...
     def write(self, data: ReadableBuffer) -> int: ...
     def writelines(self, seq: Iterable[ReadableBuffer]) -> None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/codecs.pyi

@@ -3,7 +3,7 @@ from _codecs import *
 from _typeshed import ReadableBuffer
 from abc import abstractmethod
 from collections.abc import Callable, Generator, Iterable
-from typing import Any, BinaryIO, Final, Literal, Protocol, TextIO
+from typing import Any, BinaryIO, ClassVar, Final, Literal, Protocol, TextIO
 from typing_extensions import Self
 
 __all__ = [
@@ -202,6 +202,7 @@ class StreamWriter(Codec):
     def write(self, object: str) -> None: ...
     def writelines(self, list: Iterable[str]) -> None: ...
     def reset(self) -> None: ...
+    def seek(self, offset: int, whence: int = 0) -> None: ...
     def __enter__(self) -> Self: ...
     def __exit__(self, type: type[BaseException] | None, value: BaseException | None, tb: types.TracebackType | None) -> None: ...
     def __getattr__(self, name: str, getattr: Callable[[Any, str], Any] = ...) -> Any: ...
@@ -209,11 +210,14 @@ class StreamWriter(Codec):
 class StreamReader(Codec):
     stream: _ReadableStream
     errors: str
+    # This is set to str, but some subclasses set to bytes instead.
+    charbuffertype: ClassVar[type] = ...
     def __init__(self, stream: _ReadableStream, errors: str = "strict") -> None: ...
     def read(self, size: int = -1, chars: int = -1, firstline: bool = False) -> str: ...
     def readline(self, size: int | None = None, keepends: bool = True) -> str: ...
     def readlines(self, sizehint: int | None = None, keepends: bool = True) -> list[str]: ...
     def reset(self) -> None: ...
+    def seek(self, offset: int, whence: int = 0) -> None: ...
     def __enter__(self) -> Self: ...
     def __exit__(self, type: type[BaseException] | None, value: BaseException | None, tb: types.TracebackType | None) -> None: ...
     def __iter__(self) -> Self: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/configparser.pyi

@@ -1,5 +1,5 @@
 import sys
-from _typeshed import StrOrBytesPath, SupportsWrite
+from _typeshed import MaybeNone, StrOrBytesPath, SupportsWrite
 from collections.abc import Callable, ItemsView, Iterable, Iterator, Mapping, MutableMapping, Sequence
 from re import Pattern
 from typing import Any, ClassVar, Final, Literal, TypeVar, overload
@@ -263,11 +263,11 @@ class RawConfigParser(_Parser):
     ) -> _T: ...
     # This is incompatible with MutableMapping so we ignore the type
     @overload  # type: ignore[override]
-    def get(self, section: str, option: str, *, raw: bool = False, vars: _Section | None = None) -> str | Any: ...
+    def get(self, section: str, option: str, *, raw: bool = False, vars: _Section | None = None) -> str | MaybeNone: ...
     @overload
     def get(
         self, section: str, option: str, *, raw: bool = False, vars: _Section | None = None, fallback: _T
-    ) -> str | _T | Any: ...
+    ) -> str | _T | MaybeNone: ...
     @overload
     def items(self, *, raw: bool = False, vars: _Section | None = None) -> ItemsView[str, SectionProxy]: ...
     @overload
@@ -277,6 +277,8 @@ class RawConfigParser(_Parser):
     def remove_option(self, section: str, option: str) -> bool: ...
     def remove_section(self, section: str) -> bool: ...
     def optionxform(self, optionstr: str) -> str: ...
+    @property
+    def converters(self) -> ConverterMapping: ...
 
 class ConfigParser(RawConfigParser):
     # This is incompatible with MutableMapping so we ignore the type
@@ -300,28 +302,34 @@ class SectionProxy(MutableMapping[str, str]):
     def parser(self) -> RawConfigParser: ...
     @property
     def name(self) -> str: ...
-    def get(  # type: ignore[override]
+    # This is incompatible with MutableMapping so we ignore the type
+    @overload  # type: ignore[override]
+    def get(
+        self, option: str, *, raw: bool = False, vars: _Section | None = None, _impl: Any | None = None, **kwargs: Any
+    ) -> str | None: ...
+    @overload
+    def get(
         self,
         option: str,
-        fallback: str | None = None,
+        fallback: _T,
         *,
         raw: bool = False,
         vars: _Section | None = None,
         _impl: Any | None = None,
         **kwargs: Any,
-    ) -> str | Any: ...  # can be None in RawConfigParser's sections
+    ) -> str | _T: ...
     # These are partially-applied version of the methods with the same names in
     # RawConfigParser; the stubs should be kept updated together
     @overload
-    def getint(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> int: ...
+    def getint(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> int | None: ...
     @overload
     def getint(self, option: str, fallback: _T = ..., *, raw: bool = ..., vars: _Section | None = ...) -> int | _T: ...
     @overload
-    def getfloat(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> float: ...
+    def getfloat(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> float | None: ...
     @overload
     def getfloat(self, option: str, fallback: _T = ..., *, raw: bool = ..., vars: _Section | None = ...) -> float | _T: ...
     @overload
-    def getboolean(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> bool: ...
+    def getboolean(self, option: str, *, raw: bool = ..., vars: _Section | None = ...) -> bool | None: ...
     @overload
     def getboolean(self, option: str, fallback: _T = ..., *, raw: bool = ..., vars: _Section | None = ...) -> bool | _T: ...
     # SectionProxy can have arbitrary attributes when custom converters are used

crates/red_knot_vendored/vendor/typeshed/stdlib/contextlib.pyi

@@ -1,7 +1,7 @@
 import abc
 import sys
 from _typeshed import FileDescriptorOrPath, Unused
-from abc import abstractmethod
+from abc import ABC, abstractmethod
 from collections.abc import AsyncGenerator, AsyncIterator, Awaitable, Callable, Generator, Iterator
 from types import TracebackType
 from typing import IO, Any, Generic, Protocol, TypeVar, overload, runtime_checkable
@@ -38,16 +38,22 @@ _P = ParamSpec("_P")
 _ExitFunc: TypeAlias = Callable[[type[BaseException] | None, BaseException | None, TracebackType | None], bool | None]
 _CM_EF = TypeVar("_CM_EF", bound=AbstractContextManager[Any, Any] | _ExitFunc)
 
+# mypy and pyright object to this being both ABC and Protocol.
+# At runtime it inherits from ABC and is not a Protocol, but it is on the
+# allowlist for use as a Protocol.
 @runtime_checkable
-class AbstractContextManager(Protocol[_T_co, _ExitT_co]):
+class AbstractContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
     def __enter__(self) -> _T_co: ...
     @abstractmethod
     def __exit__(
         self, exc_type: type[BaseException] | None, exc_value: BaseException | None, traceback: TracebackType | None, /
     ) -> _ExitT_co: ...
 
+# mypy and pyright object to this being both ABC and Protocol.
+# At runtime it inherits from ABC and is not a Protocol, but it is on the
+# allowlist for use as a Protocol.
 @runtime_checkable
-class AbstractAsyncContextManager(Protocol[_T_co, _ExitT_co]):
+class AbstractAsyncContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
     async def __aenter__(self) -> _T_co: ...
     @abstractmethod
     async def __aexit__(

crates/red_knot_vendored/vendor/typeshed/stdlib/crypt.pyi

@@ -1,8 +1,15 @@
 import sys
-from typing import Final
+from typing import Final, NamedTuple, type_check_only
 
 if sys.platform != "win32":
-    class _Method: ...
+    @type_check_only
+    class _MethodBase(NamedTuple):
+        name: str
+        ident: str | None
+        salt_chars: int
+        total_size: int
+
+    class _Method(_MethodBase): ...
     METHOD_CRYPT: Final[_Method]
     METHOD_MD5: Final[_Method]
     METHOD_SHA256: Final[_Method]

crates/red_knot_vendored/vendor/typeshed/stdlib/csv.pyi

@@ -8,8 +8,6 @@ from _csv import (
     __version__ as __version__,
     _DialectLike,
     _QuotingType,
-    _reader,
-    _writer,
     field_size_limit as field_size_limit,
     get_dialect as get_dialect,
     list_dialects as list_dialects,
@@ -21,6 +19,10 @@ from _csv import (
 
 if sys.version_info >= (3, 12):
     from _csv import QUOTE_NOTNULL as QUOTE_NOTNULL, QUOTE_STRINGS as QUOTE_STRINGS
+if sys.version_info >= (3, 10):
+    from _csv import Reader, Writer
+else:
+    from _csv import _reader as Reader, _writer as Writer
 
 from _typeshed import SupportsWrite
 from collections.abc import Collection, Iterable, Mapping, Sequence
@@ -77,7 +79,7 @@ class DictReader(Generic[_T]):
     fieldnames: Sequence[_T] | None
     restkey: _T | None
     restval: str | Any | None
-    reader: _reader
+    reader: Reader
     dialect: _DialectLike
     line_num: int
     @overload
@@ -125,7 +127,7 @@ class DictWriter(Generic[_T]):
     fieldnames: Collection[_T]
     restval: Any | None
     extrasaction: Literal["raise", "ignore"]
-    writer: _writer
+    writer: Writer
     def __init__(
         self,
         f: SupportsWrite[str],

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/__init__.pyi

@@ -10,13 +10,11 @@ from _ctypes import (
     _CanCastTo as _CanCastTo,
     _CArgObject as _CArgObject,
     _CData as _CData,
-    _CDataMeta as _CDataMeta,
+    _CDataType as _CDataType,
     _CField as _CField,
     _Pointer as _Pointer,
     _PointerLike as _PointerLike,
     _SimpleCData as _SimpleCData,
-    _StructUnionBase as _StructUnionBase,
-    _StructUnionMeta as _StructUnionMeta,
     addressof as addressof,
     alignment as alignment,
     byref as byref,
@@ -28,7 +26,7 @@ from _ctypes import (
 )
 from ctypes._endian import BigEndianStructure as BigEndianStructure, LittleEndianStructure as LittleEndianStructure
 from typing import Any, ClassVar, Generic, TypeVar
-from typing_extensions import TypeAlias
+from typing_extensions import Self, TypeAlias, deprecated
 
 if sys.platform == "win32":
     from _ctypes import FormatError as FormatError, get_last_error as get_last_error, set_last_error as set_last_error
@@ -41,6 +39,7 @@ if sys.version_info >= (3, 9):
 
 _T = TypeVar("_T")
 _DLLT = TypeVar("_DLLT", bound=CDLL)
+_CT = TypeVar("_CT", bound=_CData)
 
 DEFAULT_MODE: int
 
@@ -48,7 +47,7 @@ class ArgumentError(Exception): ...
 
 class CDLL:
     _func_flags_: ClassVar[int]
-    _func_restype_: ClassVar[_CData]
+    _func_restype_: ClassVar[_CDataType]
     _name: str
     _handle: int
     _FuncPtr: type[_FuncPointer]
@@ -91,15 +90,21 @@ class _NamedFuncPointer(_FuncPointer):
     __name__: str
 
 def CFUNCTYPE(
-    restype: type[_CData] | None, *argtypes: type[_CData], use_errno: bool = ..., use_last_error: bool = ...
+    restype: type[_CData | _CDataType] | None,
+    *argtypes: type[_CData | _CDataType],
+    use_errno: bool = ...,
+    use_last_error: bool = ...,
 ) -> type[_FuncPointer]: ...
 
 if sys.platform == "win32":
     def WINFUNCTYPE(
-        restype: type[_CData] | None, *argtypes: type[_CData], use_errno: bool = ..., use_last_error: bool = ...
+        restype: type[_CData | _CDataType] | None,
+        *argtypes: type[_CData | _CDataType],
+        use_errno: bool = ...,
+        use_last_error: bool = ...,
     ) -> type[_FuncPointer]: ...
 
-def PYFUNCTYPE(restype: type[_CData] | None, *argtypes: type[_CData]) -> type[_FuncPointer]: ...
+def PYFUNCTYPE(restype: type[_CData | _CDataType] | None, *argtypes: type[_CData | _CDataType]) -> type[_FuncPointer]: ...
 
 # Any type that can be implicitly converted to c_void_p when passed as a C function argument.
 # (bytes is not included here, see below.)
@@ -112,12 +117,17 @@ _CVoidConstPLike: TypeAlias = _CVoidPLike | bytes
 
 _CastT = TypeVar("_CastT", bound=_CanCastTo)
 
-def cast(obj: _CData | _CArgObject | int, typ: type[_CastT]) -> _CastT: ...
+def cast(obj: _CData | _CDataType | _CArgObject | int, typ: type[_CastT]) -> _CastT: ...
 def create_string_buffer(init: int | bytes, size: int | None = None) -> Array[c_char]: ...
 
 c_buffer = create_string_buffer
 
 def create_unicode_buffer(init: int | str, size: int | None = None) -> Array[c_wchar]: ...
+@deprecated("Deprecated in Python 3.13; removal scheduled for Python 3.15")
+def SetPointerType(
+    pointer: type[_Pointer[Any]], cls: Any  # noqa: F811  # Redefinition of unused `pointer` from line 22
+) -> None: ...
+def ARRAY(typ: _CT, len: int) -> Array[_CT]: ...  # Soft Deprecated, no plans to remove
 
 if sys.platform == "win32":
     def DllCanUnloadNow() -> int: ...
@@ -126,12 +136,12 @@ if sys.platform == "win32":
 
 def memmove(dst: _CVoidPLike, src: _CVoidConstPLike, count: int) -> int: ...
 def memset(dst: _CVoidPLike, c: int, count: int) -> int: ...
-def string_at(address: _CVoidConstPLike, size: int = -1) -> bytes: ...
+def string_at(ptr: _CVoidConstPLike, size: int = -1) -> bytes: ...
 
 if sys.platform == "win32":
     def WinError(code: int | None = None, descr: str | None = None) -> OSError: ...
 
-def wstring_at(address: _CVoidConstPLike, size: int = -1) -> str: ...
+def wstring_at(ptr: _CVoidConstPLike, size: int = -1) -> str: ...
 
 class c_byte(_SimpleCData[int]): ...
 
@@ -140,6 +150,8 @@ class c_char(_SimpleCData[bytes]):
 
 class c_char_p(_PointerLike, _SimpleCData[bytes | None]):
     def __init__(self, value: int | bytes | None = ...) -> None: ...
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 class c_double(_SimpleCData[float]): ...
 class c_longdouble(_SimpleCData[float]): ...  # can be an alias for c_double
@@ -155,7 +167,13 @@ class c_uint(_SimpleCData[int]): ...  # can be an alias for c_ulong
 class c_ulong(_SimpleCData[int]): ...
 class c_ulonglong(_SimpleCData[int]): ...  # can be an alias for c_ulong
 class c_ushort(_SimpleCData[int]): ...
-class c_void_p(_PointerLike, _SimpleCData[int | None]): ...
+
+class c_void_p(_PointerLike, _SimpleCData[int | None]):
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
+
+c_voidp = c_void_p  # backwards compatibility (to a bug)
+
 class c_wchar(_SimpleCData[str]): ...
 
 c_int8 = c_byte
@@ -174,6 +192,8 @@ class c_uint64(_SimpleCData[int]): ...
 
 class c_wchar_p(_PointerLike, _SimpleCData[str | None]):
     def __init__(self, value: int | str | None = ...) -> None: ...
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 class c_bool(_SimpleCData[bool]):
     def __init__(self, value: bool = ...) -> None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/macholib/__init__.pyi

@@ -0,0 +1 @@
+__version__: str

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/macholib/dyld.pyi

@@ -0,0 +1,8 @@
+from collections.abc import Mapping
+from ctypes.macholib.dylib import dylib_info as dylib_info
+from ctypes.macholib.framework import framework_info as framework_info
+
+__all__ = ["dyld_find", "framework_find", "framework_info", "dylib_info"]
+
+def dyld_find(name: str, executable_path: str | None = None, env: Mapping[str, str] | None = None) -> str: ...
+def framework_find(fn: str, executable_path: str | None = None, env: Mapping[str, str] | None = None) -> str: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/macholib/dylib.pyi

@@ -0,0 +1,14 @@
+from typing import TypedDict, type_check_only
+
+__all__ = ["dylib_info"]
+
+# Actual result is produced by re.match.groupdict()
+@type_check_only
+class _DylibInfo(TypedDict):
+    location: str
+    name: str
+    shortname: str
+    version: str | None
+    suffix: str | None
+
+def dylib_info(filename: str) -> _DylibInfo | None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/macholib/framework.pyi

@@ -0,0 +1,14 @@
+from typing import TypedDict, type_check_only
+
+__all__ = ["framework_info"]
+
+# Actual result is produced by re.match.groupdict()
+@type_check_only
+class _FrameworkInfo(TypedDict):
+    location: str
+    name: str
+    shortname: str
+    version: str | None
+    suffix: str | None
+
+def framework_info(filename: str) -> _FrameworkInfo | None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/util.pyi

@@ -4,3 +4,5 @@ def find_library(name: str) -> str | None: ...
 
 if sys.platform == "win32":
     def find_msvcrt() -> str | None: ...
+
+def test() -> None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/ctypes/wintypes.pyi

@@ -1,7 +1,7 @@
+from _ctypes import _CArgObject, _CField
 from ctypes import (
     Array,
     Structure,
-    _CField,
     _Pointer,
     _SimpleCData,
     c_byte,
@@ -21,8 +21,8 @@ from ctypes import (
     c_wchar,
     c_wchar_p,
 )
-from typing import TypeVar
-from typing_extensions import TypeAlias
+from typing import Any, TypeVar
+from typing_extensions import Self, TypeAlias
 
 BYTE = c_byte
 WORD = c_ushort
@@ -241,10 +241,16 @@ LPBYTE = PBYTE
 PBOOLEAN = PBYTE
 
 # LP_c_char
-class PCHAR(_Pointer[CHAR]): ...
+class PCHAR(_Pointer[CHAR]):
+    # this is inherited from ctypes.c_char_p, kind of.
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 # LP_c_wchar
-class PWCHAR(_Pointer[WCHAR]): ...
+class PWCHAR(_Pointer[WCHAR]):
+    # inherited from ctypes.c_wchar_p, kind of
+    @classmethod
+    def from_param(cls, value: Any, /) -> Self | _CArgObject: ...
 
 # LP_c_void_p
 class PHANDLE(_Pointer[HANDLE]): ...

crates/red_knot_vendored/vendor/typeshed/stdlib/curses/__init__.pyi

@@ -1,7 +1,9 @@
+import sys
 from _curses import *
 from _curses import window as window
+from _typeshed import structseq
 from collections.abc import Callable
-from typing import TypeVar
+from typing import Final, TypeVar, final, type_check_only
 from typing_extensions import Concatenate, ParamSpec
 
 # NOTE: The _curses module is ordinarily only available on Unix, but the
@@ -25,3 +27,19 @@ def wrapper(func: Callable[Concatenate[window, _P], _T], /, *arg: _P.args, **kwd
 # it was mapped to the name 'window' in 3.8.
 # Kept here as a legacy alias in case any third-party code is relying on it.
 _CursesWindow = window
+
+# At runtime this class is unexposed and calls itself curses.ncurses_version.
+# That name would conflict with the actual curses.ncurses_version, which is
+# an instance of this class.
+@final
+@type_check_only
+class _ncurses_version(structseq[int], tuple[int, int, int]):
+    if sys.version_info >= (3, 10):
+        __match_args__: Final = ("major", "minor", "patch")
+
+    @property
+    def major(self) -> int: ...
+    @property
+    def minor(self) -> int: ...
+    @property
+    def patch(self) -> int: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/curses/panel.pyi

@@ -1,22 +1 @@
-from _curses import window
-
-version: str
-
-class _Curses_Panel:  # type is <class '_curses_panel.curses panel'> (note the space in the class name)
-    def above(self) -> _Curses_Panel: ...
-    def below(self) -> _Curses_Panel: ...
-    def bottom(self) -> None: ...
-    def hidden(self) -> bool: ...
-    def hide(self) -> None: ...
-    def move(self, y: int, x: int) -> None: ...
-    def replace(self, win: window) -> None: ...
-    def set_userptr(self, obj: object) -> None: ...
-    def show(self) -> None: ...
-    def top(self) -> None: ...
-    def userptr(self) -> object: ...
-    def window(self) -> window: ...
-
-def bottom_panel() -> _Curses_Panel: ...
-def new_panel(win: window, /) -> _Curses_Panel: ...
-def top_panel() -> _Curses_Panel: ...
-def update_panels() -> _Curses_Panel: ...
+from _curses_panel import *

crates/red_knot_vendored/vendor/typeshed/stdlib/datetime.pyi

@@ -1,8 +1,8 @@
 import sys
 from abc import abstractmethod
 from time import struct_time
-from typing import ClassVar, Final, NamedTuple, NoReturn, SupportsIndex, final, overload
-from typing_extensions import Self, TypeAlias, deprecated
+from typing import ClassVar, Final, NoReturn, SupportsIndex, final, overload, type_check_only
+from typing_extensions import CapsuleType, Self, TypeAlias, deprecated
 
 if sys.version_info >= (3, 11):
     __all__ = ("date", "datetime", "time", "timedelta", "timezone", "tzinfo", "MINYEAR", "MAXYEAR", "UTC")
@@ -40,10 +40,17 @@ if sys.version_info >= (3, 11):
     UTC: timezone
 
 if sys.version_info >= (3, 9):
-    class _IsoCalendarDate(NamedTuple):
-        year: int
-        week: int
-        weekday: int
+    # This class calls itself datetime.IsoCalendarDate. It's neither
+    # NamedTuple nor structseq.
+    @final
+    @type_check_only
+    class _IsoCalendarDate(tuple[int, int, int]):
+        @property
+        def year(self) -> int: ...
+        @property
+        def week(self) -> int: ...
+        @property
+        def weekday(self) -> int: ...
 
 class date:
     min: ClassVar[date]
@@ -325,3 +332,5 @@ class datetime(date):
     def __sub__(self, value: Self, /) -> timedelta: ...
     @overload
     def __sub__(self, value: timedelta, /) -> Self: ...
+
+datetime_CAPI: CapsuleType

crates/red_knot_vendored/vendor/typeshed/stdlib/dbm/__init__.pyi

@@ -2,7 +2,7 @@ import sys
 from _typeshed import StrOrBytesPath
 from collections.abc import Iterator, MutableMapping
 from types import TracebackType
-from typing import Literal
+from typing import Literal, type_check_only
 from typing_extensions import Self, TypeAlias
 
 __all__ = ["open", "whichdb", "error"]
@@ -89,6 +89,8 @@ class _Database(MutableMapping[_KeyType, bytes]):
         self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: TracebackType | None
     ) -> None: ...
 
+# This class is not exposed. It calls itself dbm.error.
+@type_check_only
 class _error(Exception): ...
 
 error: tuple[type[_error], type[OSError]]

crates/red_knot_vendored/vendor/typeshed/stdlib/decimal.pyi

@@ -24,7 +24,8 @@ from _decimal import (
     setcontext as setcontext,
 )
 from collections.abc import Container, Sequence
-from typing import Any, ClassVar, Literal, NamedTuple, overload
+from types import TracebackType
+from typing import Any, ClassVar, Literal, NamedTuple, final, overload, type_check_only
 from typing_extensions import Self, TypeAlias
 
 _Decimal: TypeAlias = Decimal | int
@@ -35,6 +36,14 @@ _TrapType: TypeAlias = type[DecimalException]
 # At runtime, these classes are implemented in C as part of "_decimal".
 # However, they consider themselves to live in "decimal", so we'll put them here.
 
+# This type isn't exposed at runtime. It calls itself decimal.ContextManager
+@final
+@type_check_only
+class _ContextManager:
+    def __init__(self, new_context: Context) -> None: ...
+    def __enter__(self) -> Context: ...
+    def __exit__(self, t: type[BaseException] | None, v: BaseException | None, tb: TracebackType | None) -> None: ...
+
 class DecimalTuple(NamedTuple):
     sign: int
     digits: tuple[int, ...]

crates/red_knot_vendored/vendor/typeshed/stdlib/distutils/ccompiler.pyi

@@ -165,7 +165,7 @@ class CCompiler:
     def execute(
         self, func: Callable[[Unpack[_Ts]], Unused], args: tuple[Unpack[_Ts]], msg: str | None = None, level: int = 1
     ) -> None: ...
-    def spawn(self, cmd: list[str]) -> None: ...
+    def spawn(self, cmd: Iterable[str]) -> None: ...
     def mkpath(self, name: str, mode: int = 0o777) -> None: ...
     @overload
     def move_file(self, src: StrPath, dst: _StrPathT) -> _StrPathT | str: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/distutils/spawn.pyi

@@ -1,6 +1,10 @@
+from collections.abc import Iterable
 from typing import Literal
 
 def spawn(
-    cmd: list[str], search_path: bool | Literal[0, 1] = 1, verbose: bool | Literal[0, 1] = 0, dry_run: bool | Literal[0, 1] = 0
+    cmd: Iterable[str],
+    search_path: bool | Literal[0, 1] = 1,
+    verbose: bool | Literal[0, 1] = 0,
+    dry_run: bool | Literal[0, 1] = 0,
 ) -> None: ...
 def find_executable(executable: str, path: str | None = None) -> str | None: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/doctest.pyi

@@ -3,7 +3,7 @@ import types
 import unittest
 from _typeshed import ExcInfo
 from collections.abc import Callable
-from typing import Any, ClassVar, NamedTuple
+from typing import Any, NamedTuple, type_check_only
 from typing_extensions import Self, TypeAlias
 
 __all__ = [
@@ -42,17 +42,15 @@ __all__ = [
     "debug",
 ]
 
-# MyPy errors on conditionals within named tuples.
-
 if sys.version_info >= (3, 13):
-    class TestResults(NamedTuple):
-        def __new__(cls, failed: int, attempted: int, *, skipped: int = 0) -> Self: ...  # type: ignore[misc]
-        skipped: int
+    @type_check_only
+    class _TestResultsBase(NamedTuple):
         failed: int
         attempted: int
-        _fields: ClassVar = ("failed", "attempted")  # type: ignore[misc]
-        __match_args__ = ("failed", "attempted")  # type: ignore[misc]
-        __doc__: None  # type: ignore[misc]
+
+    class TestResults(_TestResultsBase):
+        def __new__(cls, failed: int, attempted: int, *, skipped: int = 0) -> Self: ...
+        skipped: int
 
 else:
     class TestResults(NamedTuple):

crates/red_knot_vendored/vendor/typeshed/stdlib/email/__init__.pyi

@@ -4,6 +4,29 @@ from email.policy import Policy
 from typing import IO
 from typing_extensions import TypeAlias
 
+# At runtime, listing submodules in __all__ without them being imported is
+# valid, and causes them to be included in a star import. See #6523
+
+__all__ = [  # noqa: F822  # Undefined names in __all__
+    "base64mime",  # pyright: ignore[reportUnsupportedDunderAll]
+    "charset",  # pyright: ignore[reportUnsupportedDunderAll]
+    "encoders",  # pyright: ignore[reportUnsupportedDunderAll]
+    "errors",  # pyright: ignore[reportUnsupportedDunderAll]
+    "feedparser",  # pyright: ignore[reportUnsupportedDunderAll]
+    "generator",  # pyright: ignore[reportUnsupportedDunderAll]
+    "header",  # pyright: ignore[reportUnsupportedDunderAll]
+    "iterators",  # pyright: ignore[reportUnsupportedDunderAll]
+    "message",  # pyright: ignore[reportUnsupportedDunderAll]
+    "message_from_file",
+    "message_from_binary_file",
+    "message_from_string",
+    "message_from_bytes",
+    "mime",  # pyright: ignore[reportUnsupportedDunderAll]
+    "parser",  # pyright: ignore[reportUnsupportedDunderAll]
+    "quoprimime",  # pyright: ignore[reportUnsupportedDunderAll]
+    "utils",  # pyright: ignore[reportUnsupportedDunderAll]
+]
+
 # Definitions imported by multiple submodules in typeshed
 _ParamType: TypeAlias = str | tuple[str | None, str | None, str]  # noqa: Y047
 _ParamsType: TypeAlias = str | None | tuple[str, str | None, str]  # noqa: Y047
@@ -12,18 +35,3 @@ def message_from_string(s: str, _class: Callable[[], Message] = ..., *, policy:
 def message_from_bytes(s: bytes | bytearray, _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
 def message_from_file(fp: IO[str], _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
 def message_from_binary_file(fp: IO[bytes], _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
-
-# Names in __all__ with no definition:
-#   base64mime
-#   charset
-#   encoders
-#   errors
-#   feedparser
-#   generator
-#   header
-#   iterators
-#   message
-#   mime
-#   parser
-#   quoprimime
-#   utils

crates/red_knot_vendored/vendor/typeshed/stdlib/email/_policybase.pyi

@@ -5,6 +5,8 @@ from email.message import Message
 from typing import Generic, Protocol, TypeVar, type_check_only
 from typing_extensions import Self
 
+__all__ = ["Policy", "Compat32", "compat32"]
+
 _MessageT = TypeVar("_MessageT", bound=Message, default=Message)
 
 @type_check_only

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/aliases.pyi

@@ -0,0 +1 @@
+aliases: dict[str, str]

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/ascii.pyi

@@ -0,0 +1,30 @@
+import codecs
+from _typeshed import ReadableBuffer
+
+class Codec(codecs.Codec):
+    # At runtime, this is codecs.ascii_encode
+    @staticmethod
+    def encode(str: str, errors: str | None = None, /) -> tuple[bytes, int]: ...
+    # At runtime, this is codecs.ascii_decode
+    @staticmethod
+    def decode(data: ReadableBuffer, errors: str | None = None, /) -> tuple[str, int]: ...
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def encode(self, input: str, final: bool = False) -> bytes: ...
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    def decode(self, input: ReadableBuffer, final: bool = False) -> str: ...
+
+class StreamWriter(Codec, codecs.StreamWriter): ...
+class StreamReader(Codec, codecs.StreamReader): ...
+
+# Note: encode being a decode function and decode being an encode function is accurate to runtime.
+class StreamConverter(StreamWriter, StreamReader):  # type: ignore[misc]  # incompatible methods in base classes
+    # At runtime, this is codecs.ascii_decode
+    @staticmethod
+    def encode(data: ReadableBuffer, errors: str | None = None, /) -> tuple[str, int]: ...  # type: ignore[override]
+    # At runtime, this is codecs.ascii_encode
+    @staticmethod
+    def decode(str: str, errors: str | None = None, /) -> tuple[bytes, int]: ...  # type: ignore[override]
+
+def getregentry() -> codecs.CodecInfo: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/base64_codec.pyi

@@ -0,0 +1,26 @@
+import codecs
+from _typeshed import ReadableBuffer
+from typing import ClassVar
+
+# This codec is bytes to bytes.
+
+def base64_encode(input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...
+def base64_decode(input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...
+
+class Codec(codecs.Codec):
+    def encode(self, input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...  # type: ignore[override]
+    def decode(self, input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...  # type: ignore[override]
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def encode(self, input: ReadableBuffer, final: bool = False) -> bytes: ...  # type: ignore[override]
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    def decode(self, input: ReadableBuffer, final: bool = False) -> bytes: ...  # type: ignore[override]
+
+class StreamWriter(Codec, codecs.StreamWriter):
+    charbuffertype: ClassVar[type] = ...
+
+class StreamReader(Codec, codecs.StreamReader):
+    charbuffertype: ClassVar[type] = ...
+
+def getregentry() -> codecs.CodecInfo: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/big5.pyi

@@ -0,0 +1,23 @@
+import _multibytecodec as mbc
+import codecs
+from typing import ClassVar
+
+codec: mbc._MultibyteCodec
+
+class Codec(codecs.Codec):
+    encode = codec.encode  # type: ignore[assignment]  # pyright: ignore[reportAssignmentType]
+    decode = codec.decode  # type: ignore[assignment]  # pyright: ignore[reportAssignmentType]
+
+class IncrementalEncoder(mbc.MultibyteIncrementalEncoder, codecs.IncrementalEncoder):  # type: ignore[misc]
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class IncrementalDecoder(mbc.MultibyteIncrementalDecoder, codecs.IncrementalDecoder):
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class StreamReader(Codec, mbc.MultibyteStreamReader, codecs.StreamReader):  # type: ignore[misc]
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class StreamWriter(Codec, mbc.MultibyteStreamWriter, codecs.StreamWriter):
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+def getregentry() -> codecs.CodecInfo: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/big5hkscs.pyi

@@ -0,0 +1,23 @@
+import _multibytecodec as mbc
+import codecs
+from typing import ClassVar
+
+codec: mbc._MultibyteCodec
+
+class Codec(codecs.Codec):
+    encode = codec.encode  # type: ignore[assignment]  # pyright: ignore[reportAssignmentType]
+    decode = codec.decode  # type: ignore[assignment]  # pyright: ignore[reportAssignmentType]
+
+class IncrementalEncoder(mbc.MultibyteIncrementalEncoder, codecs.IncrementalEncoder):  # type: ignore[misc]
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class IncrementalDecoder(mbc.MultibyteIncrementalDecoder, codecs.IncrementalDecoder):
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class StreamReader(Codec, mbc.MultibyteStreamReader, codecs.StreamReader):  # type: ignore[misc]
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+class StreamWriter(Codec, mbc.MultibyteStreamWriter, codecs.StreamWriter):
+    codec: ClassVar[mbc._MultibyteCodec] = ...
+
+def getregentry() -> codecs.CodecInfo: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/bz2_codec.pyi

@@ -0,0 +1,26 @@
+import codecs
+from _typeshed import ReadableBuffer
+from typing import ClassVar
+
+# This codec is bytes to bytes.
+
+def bz2_encode(input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...
+def bz2_decode(input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...
+
+class Codec(codecs.Codec):
+    def encode(self, input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...  # type: ignore[override]
+    def decode(self, input: ReadableBuffer, errors: str = "strict") -> tuple[bytes, int]: ...  # type: ignore[override]
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    def encode(self, input: ReadableBuffer, final: bool = False) -> bytes: ...  # type: ignore[override]
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    def decode(self, input: ReadableBuffer, final: bool = False) -> bytes: ...  # type: ignore[override]
+
+class StreamWriter(Codec, codecs.StreamWriter):
+    charbuffertype: ClassVar[type] = ...
+
+class StreamReader(Codec, codecs.StreamReader):
+    charbuffertype: ClassVar[type] = ...
+
+def getregentry() -> codecs.CodecInfo: ...

crates/red_knot_vendored/vendor/typeshed/stdlib/encodings/charmap.pyi

@@ -0,0 +1,33 @@
+import codecs
+from _codecs import _CharMap
+from _typeshed import ReadableBuffer
+
+class Codec(codecs.Codec):
+    # At runtime, this is codecs.charmap_encode
+    @staticmethod
+    def encode(str: str, errors: str | None = None, mapping: _CharMap | None = None, /) -> tuple[bytes, int]: ...
+    # At runtime, this is codecs.charmap_decode
+    @staticmethod
+    def decode(data: ReadableBuffer, errors: str | None = None, mapping: _CharMap | None = None, /) -> tuple[str, int]: ...
+
+class IncrementalEncoder(codecs.IncrementalEncoder):
+    mapping: _CharMap | None
+    def __init__(self, errors: str = "strict", mapping: _CharMap | None = None) -> None: ...
+    def encode(self, input: str, final: bool = False) -> bytes: ...
+
+class IncrementalDecoder(codecs.IncrementalDecoder):
+    mapping: _CharMap | None
+    def __init__(self, errors: str = "strict", mapping: _CharMap | None = None) -> None: ...
+    def decode(self, input: ReadableBuffer, final: bool = False) -> str: ...
+
+class StreamWriter(Codec, codecs.StreamWriter):
+    mapping: _CharMap | None
+    def __init__(self, stream: codecs._WritableStream, errors: str = "strict", mapping: _CharMap | None = None) -> None: ...
+    def encode(self, input: str, errors: str = "strict") -> tuple[bytes, int]: ...  # type: ignore[override]
+
+class StreamReader(Codec, codecs.StreamReader):
+    mapping: _CharMap | None
+    def __init__(self, stream: codecs._ReadableStream, errors: str = "strict", mapping: _CharMap | None = None) -> None: ...
+    def decode(self, input: ReadableBuffer, errors: str = "strict") -> tuple[str, int]: ...  # type: ignore[override]
+
+def getregentry() -> codecs.CodecInfo: ...