Separate TOC from the navigation

2024-09-05 16:08:53 +05:30
917 changed files with 3677 additions and 22889 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -1,5 +1,3 @@
-# This file was autogenerated by cargo-dist: https://opensource.axo.dev/cargo-dist/
-#
 # Copyright 2022-2024, axodotdev
 # SPDX-License-Identifier: MIT or Apache-2.0
 #
@@ -66,7 +64,7 @@ jobs:
        # we specify bash to get pipefail; it guards against the `curl` command
        # failing. otherwise `sh` won't catch that `curl` returned non-0
        shell: bash
-        run: "curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.22.1/cargo-dist-installer.sh | sh"
+        run: "curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.18.0/cargo-dist-installer.sh | sh"
      - name: Cache cargo-dist
        uses: actions/upload-artifact@v4
        with:
--- a/.github/workflows/sync_typeshed.yaml
+++ b/.github/workflows/sync_typeshed.yaml
@@ -37,13 +37,13 @@ jobs:
      - name: Sync typeshed
        id: sync
        run: |
-          rm -rf ruff/crates/red_knot_vendored/vendor/typeshed
-          mkdir ruff/crates/red_knot_vendored/vendor/typeshed
-          cp typeshed/README.md ruff/crates/red_knot_vendored/vendor/typeshed
-          cp typeshed/LICENSE ruff/crates/red_knot_vendored/vendor/typeshed
-          cp -r typeshed/stdlib ruff/crates/red_knot_vendored/vendor/typeshed/stdlib
-          rm -rf ruff/crates/red_knot_vendored/vendor/typeshed/stdlib/@tests
-          git -C typeshed rev-parse HEAD > ruff/crates/red_knot_vendored/vendor/typeshed/source_commit.txt
+          rm -rf ruff/crates/red_knot_python_semantic/vendor/typeshed
+          mkdir ruff/crates/red_knot_python_semantic/vendor/typeshed
+          cp typeshed/README.md ruff/crates/red_knot_python_semantic/vendor/typeshed
+          cp typeshed/LICENSE ruff/crates/red_knot_python_semantic/vendor/typeshed
+          cp -r typeshed/stdlib ruff/crates/red_knot_python_semantic/vendor/typeshed/stdlib
+          rm -rf ruff/crates/red_knot_python_semantic/vendor/typeshed/stdlib/@tests
+          git -C typeshed rev-parse HEAD > ruff/crates/red_knot_python_semantic/vendor/typeshed/source_commit.txt
      - name: Commit the changes
        id: commit
        if: ${{ steps.sync.outcome == 'success' }}
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -2,7 +2,7 @@ fail_fast: true

 exclude: |
  (?x)^(
-    crates/red_knot_vendored/vendor/.*|
+    crates/red_knot_python_semantic/vendor/.*|
    crates/red_knot_workspace/resources/.*|
    crates/ruff_linter/resources/.*|
    crates/ruff_linter/src/rules/.*/snapshots/.*|
@@ -17,7 +17,7 @@ exclude: |

 repos:
  - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.20.2
+    rev: v0.19
    hooks:
      - id: validate-pyproject

@@ -35,7 +35,7 @@ repos:
          )$

  - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.42.0
+    rev: v0.41.0
    hooks:
      - id: markdownlint-fix
        exclude: |
@@ -45,7 +45,7 @@ repos:
          )$

  - repo: https://github.com/crate-ci/typos
-    rev: v1.24.6
+    rev: v1.24.3
    hooks:
      - id: typos

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

  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.8
+    rev: v0.6.3
    hooks:
      - id: ruff-format
      - id: ruff
@@ -68,8 +68,8 @@ repos:
        require_serial: true

  # Prettier
-  - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.3.3
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v3.1.0
    hooks:
      - id: prettier
        types: [yaml]
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,164 +1,5 @@
 # Changelog

-## 0.6.9
-
-### Preview features
-
- Fix codeblock dynamic line length calculation for indented docstring examples ([#13523](https://github.com/astral-sh/ruff/pull/13523))
- \[`refurb`\] Mark `FURB118` fix as unsafe ([#13613](https://github.com/astral-sh/ruff/pull/13613))
-
-### Rule changes
-
- \[`pydocstyle`\] Don't raise `D208` when last line is non-empty ([#13372](https://github.com/astral-sh/ruff/pull/13372))
- \[`pylint`\] Preserve trivia (i.e. comments) in `PLR5501` autofix ([#13573](https://github.com/astral-sh/ruff/pull/13573))
-
-### Configuration
-
- \[`pyflakes`\] Add `allow-unused-imports` setting for `unused-import` rule (`F401`) ([#13601](https://github.com/astral-sh/ruff/pull/13601))
-
-### Bug fixes
-
- Support ruff discovery in pip build environments ([#13591](https://github.com/astral-sh/ruff/pull/13591))
- \[`flake8-bugbear`\] Avoid short circuiting `B017` for multiple context managers ([#13609](https://github.com/astral-sh/ruff/pull/13609))
- \[`pylint`\] Do not offer an invalid fix for `PLR1716` when the comparisons contain parenthesis ([#13527](https://github.com/astral-sh/ruff/pull/13527))
- \[`pyupgrade`\] Fix `UP043` to apply to `collections.abc.Generator` and `collections.abc.AsyncGenerator` ([#13611](https://github.com/astral-sh/ruff/pull/13611))
- \[`refurb`\] Fix handling of slices in tuples for `FURB118`, e.g., `x[:, 1]` ([#13518](https://github.com/astral-sh/ruff/pull/13518))
-
-### Documentation
-
- Update GitHub Action link to `astral-sh/ruff-action` ([#13551](https://github.com/astral-sh/ruff/pull/13551))
-
-## 0.6.8
-
-### Preview features
-
- Remove unnecessary parentheses around `match case` clauses ([#13510](https://github.com/astral-sh/ruff/pull/13510))
- Parenthesize overlong `if` guards in `match..case` clauses ([#13513](https://github.com/astral-sh/ruff/pull/13513))
- Detect basic wildcard imports in `ruff analyze graph` ([#13486](https://github.com/astral-sh/ruff/pull/13486))
- \[`pylint`\] Implement `boolean-chained-comparison` (`R1716`) ([#13435](https://github.com/astral-sh/ruff/pull/13435))
-
-### Rule changes
-
- \[`lake8-simplify`\] Detect `SIM910` when using variadic keyword arguments, i.e., `**kwargs` ([#13503](https://github.com/astral-sh/ruff/pull/13503))
- \[`pyupgrade`\] Avoid false negatives with non-reference shadowed bindings of loop variables (`UP028`) ([#13504](https://github.com/astral-sh/ruff/pull/13504))
-
-### Bug fixes
-
- Detect tuples bound to variadic positional arguments i.e. `*args` ([#13512](https://github.com/astral-sh/ruff/pull/13512))
- Exit gracefully on broken pipe errors ([#13485](https://github.com/astral-sh/ruff/pull/13485))
- Avoid panic when analyze graph hits broken pipe ([#13484](https://github.com/astral-sh/ruff/pull/13484))
-
-### Performance
-
- Reuse `BTreeSets` in module resolver ([#13440](https://github.com/astral-sh/ruff/pull/13440))
- Skip traversal for non-compound statements ([#13441](https://github.com/astral-sh/ruff/pull/13441))
-
-## 0.6.7
-
-### Preview features
-
- Add Python version support to ruff analyze CLI ([#13426](https://github.com/astral-sh/ruff/pull/13426))
- Add `exclude` support to `ruff analyze` ([#13425](https://github.com/astral-sh/ruff/pull/13425))
- Fix parentheses around return type annotations ([#13381](https://github.com/astral-sh/ruff/pull/13381))
-
-### Rule changes
-
- \[`pycodestyle`\] Fix: Don't autofix if the first line ends in a question mark? (D400) ([#13399](https://github.com/astral-sh/ruff/pull/13399))
-
-### Bug fixes
-
- Respect `lint.exclude` in ruff check `--add-noqa` ([#13427](https://github.com/astral-sh/ruff/pull/13427))
-
-### Performance
-
- Avoid tracking module resolver files in Salsa ([#13437](https://github.com/astral-sh/ruff/pull/13437))
- Use `forget` for module resolver database ([#13438](https://github.com/astral-sh/ruff/pull/13438))
-
-## 0.6.6
-
-### Preview features
-
- \[`refurb`\] Skip `slice-to-remove-prefix-or-suffix` (`FURB188`) when non-trivial slice steps are present ([#13405](https://github.com/astral-sh/ruff/pull/13405))
- Add a subcommand to generate dependency graphs ([#13402](https://github.com/astral-sh/ruff/pull/13402))
-
-### Formatter
-
- Fix placement of inline parameter comments ([#13379](https://github.com/astral-sh/ruff/pull/13379))
-
-### Server
-
- Fix off-by one error in the `LineIndex::offset` calculation ([#13407](https://github.com/astral-sh/ruff/pull/13407))
-
-### Bug fixes
-
- \[`fastapi`\] Respect FastAPI aliases in route definitions ([#13394](https://github.com/astral-sh/ruff/pull/13394))
- \[`pydocstyle`\] Respect word boundaries when detecting function signature in docs ([#13388](https://github.com/astral-sh/ruff/pull/13388))
-
-### Documentation
-
- Add backlinks to rule overview linter ([#13368](https://github.com/astral-sh/ruff/pull/13368))
- Fix documentation for editor vim plugin ALE ([#13348](https://github.com/astral-sh/ruff/pull/13348))
- Fix rendering of `FURB188` docs ([#13406](https://github.com/astral-sh/ruff/pull/13406))
-
-## 0.6.5
-
-### Preview features
-
- \[`pydoclint`\] Ignore `DOC201` when function name is "**new**" ([#13300](https://github.com/astral-sh/ruff/pull/13300))
- \[`refurb`\] Implement `slice-to-remove-prefix-or-suffix` (`FURB188`) ([#13256](https://github.com/astral-sh/ruff/pull/13256))
-
-### Rule changes
-
- \[`eradicate`\] Ignore script-comments with multiple end-tags (`ERA001`) ([#13283](https://github.com/astral-sh/ruff/pull/13283))
- \[`pyflakes`\] Improve error message for `UndefinedName` when a builtin was added in a newer version than specified in Ruff config (`F821`) ([#13293](https://github.com/astral-sh/ruff/pull/13293))
-
-### Server
-
- Add support for extensionless Python files for server ([#13326](https://github.com/astral-sh/ruff/pull/13326))
- Fix configuration inheritance for configurations specified in the LSP settings ([#13285](https://github.com/astral-sh/ruff/pull/13285))
-
-### Bug fixes
-
- \[`ruff`\] Handle unary operators in `decimal-from-float-literal` (`RUF032`) ([#13275](https://github.com/astral-sh/ruff/pull/13275))
-
-### CLI
-
- Only include rules with diagnostics in SARIF metadata ([#13268](https://github.com/astral-sh/ruff/pull/13268))
-
-### Playground
-
- Add "Copy as pyproject.toml/ruff.toml" and "Paste from TOML" ([#13328](https://github.com/astral-sh/ruff/pull/13328))
- Fix errors not shown for restored snippet on page load ([#13262](https://github.com/astral-sh/ruff/pull/13262))
-
-## 0.6.4
-
-### Preview features
-
- \[`flake8-builtins`\] Use dynamic builtins list based on Python version ([#13172](https://github.com/astral-sh/ruff/pull/13172))
- \[`pydoclint`\] Permit yielding `None` in `DOC402` and `DOC403` ([#13148](https://github.com/astral-sh/ruff/pull/13148))
- \[`pylint`\] Update diagnostic message for `PLW3201` ([#13194](https://github.com/astral-sh/ruff/pull/13194))
- \[`ruff`\] Implement `post-init-default` (`RUF033`) ([#13192](https://github.com/astral-sh/ruff/pull/13192))
- \[`ruff`\] Implement useless if-else (`RUF034`) ([#13218](https://github.com/astral-sh/ruff/pull/13218))
-
-### Rule changes
-
- \[`flake8-pyi`\] Respect `pep8_naming.classmethod-decorators` settings when determining if a method is a classmethod in `custom-type-var-return-type` (`PYI019`) ([#13162](https://github.com/astral-sh/ruff/pull/13162))
- \[`flake8-pyi`\] Teach various rules that annotations might be stringized ([#12951](https://github.com/astral-sh/ruff/pull/12951))
- \[`pylint`\] Avoid `no-self-use` for `attrs`-style validators ([#13166](https://github.com/astral-sh/ruff/pull/13166))
- \[`pylint`\] Recurse into subscript subexpressions when searching for list/dict lookups (`PLR1733`, `PLR1736`) ([#13186](https://github.com/astral-sh/ruff/pull/13186))
- \[`pyupgrade`\] Detect `aiofiles.open` calls in `UP015` ([#13173](https://github.com/astral-sh/ruff/pull/13173))
- \[`pyupgrade`\] Mark `sys.version_info[0] < 3` and similar comparisons as outdated (`UP036`) ([#13175](https://github.com/astral-sh/ruff/pull/13175))
-
-### CLI
-
- Enrich messages of SARIF results ([#13180](https://github.com/astral-sh/ruff/pull/13180))
- Handle singular case for incompatible rules warning in `ruff format` output ([#13212](https://github.com/astral-sh/ruff/pull/13212))
-
-### Bug fixes
-
- \[`pydocstyle`\] Improve heuristics for detecting Google-style docstrings ([#13142](https://github.com/astral-sh/ruff/pull/13142))
- \[`refurb`\] Treat `sep` arguments with effects as unsafe removals (`FURB105`) ([#13165](https://github.com/astral-sh/ruff/pull/13165))
-
 ## 0.6.3

 ### Preview features
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -29,14 +29,16 @@ You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
 cargo install cargo-insta
 ```

-You'll need [uv](https://docs.astral.sh/uv/getting-started/installation/) (or `pipx` and `pip`) to
-run Python utility commands.
+And you'll need pre-commit to run some validation checks:
+
+```shell
+pipx install pre-commit  # or `pip install pre-commit` if you have a virtualenv
+```

 You can optionally install pre-commit hooks to automatically run the validation checks
 when making a commit:

 ```shell
-uv tool install pre-commit
 pre-commit install
 ```

@@ -64,7 +66,7 @@ and that it passes both the lint and test validation checks:
 ```shell
 cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
 RUFF_UPDATE_SCHEMA=1 cargo test  # Rust testing and updating ruff.schema.json
-uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
 ```

 These checks will run on GitHub Actions when you open your pull request, but running them locally
@@ -265,20 +267,26 @@ To preview any changes to the documentation locally:

 1. Install the [Rust toolchain](https://www.rust-lang.org/tools/install).

+1. Install MkDocs and Material for MkDocs with:
+
+    ```shell
+    pip install -r docs/requirements.txt
+    ```
+
 1. Generate the MkDocs site with:

    ```shell
-    uv run --no-project --isolated --with-requirements docs/requirements.txt scripts/generate_mkdocs.py
+    python scripts/generate_mkdocs.py
    ```

 1. Run the development server with:

    ```shell
    # For contributors.
-    uvx --with-requirements docs/requirements.txt -- mkdocs serve -f mkdocs.public.yml
+    mkdocs serve -f mkdocs.public.yml

    # For members of the Astral org, which has access to MkDocs Insiders via sponsorship.
-    uvx --with-requirements docs/requirements-insiders.txt -- mkdocs serve -f mkdocs.insiders.yml
+    mkdocs serve -f mkdocs.insiders.yml
    ```

 The documentation should then be available locally at
@@ -360,8 +368,9 @@ GitHub Actions will run your changes against a number of real-world projects fro
 report on any linter or formatter differences. You can also run those checks locally via:

 ```shell
-uvx --from ./python/ruff-ecosystem ruff-ecosystem check ruff "./target/debug/ruff"
-uvx --from ./python/ruff-ecosystem ruff-ecosystem format ruff "./target/debug/ruff"
+pip install -e ./python/ruff-ecosystem
+ruff-ecosystem check ruff "./target/debug/ruff"
+ruff-ecosystem format ruff "./target/debug/ruff"
 ```

 See the [ruff-ecosystem package](https://github.com/astral-sh/ruff/tree/main/python/ruff-ecosystem) for more details.
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -129,9 +129,9 @@ dependencies = [

 [[package]]
 name = "anyhow"
-version = "1.0.89"
+version = "1.0.86"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86fdf8605db99b54d3cd748a44c6d04df638eb5dafb219b135d0149bd0db01f6"
+checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"

 [[package]]
 name = "append-only-vec"
@@ -161,21 +161,6 @@ version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96d30a06541fbafbc7f82ed10c06164cfbd2c401138f6addd8404629c4b16711"

-[[package]]
-name = "assert_fs"
-version = "1.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7efdb1fdb47602827a342857666feb372712cbc64b414172bd6b167a02927674"
-dependencies = [
- "anstyle",
- "doc-comment",
- "globwalk",
- "predicates",
- "predicates-core",
- "predicates-tree",
- "tempfile",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.2.0"
@@ -209,15 +194,6 @@ version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"

-[[package]]
-name = "block-buffer"
-version = "0.10.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
-dependencies = [
- "generic-array",
-]
-
 [[package]]
 name = "bstr"
 version = "1.10.0"
@@ -225,7 +201,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40723b8fb387abc38f4f4a37c09073622e41dd12327033091ef8950659e6dc0c"
 dependencies = [
 "memchr",
- "regex-automata 0.4.8",
+ "regex-automata 0.4.6",
 "serde",
 ]

@@ -255,9 +231,6 @@ name = "camino"
 version = "1.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b96ec4966b5813e2c0507c1f86115c8c5abaadc3980879c3424042a02fd1ad3"
-dependencies = [
- "serde",
-]

 [[package]]
 name = "cast"
@@ -353,9 +326,9 @@ dependencies = [

 [[package]]
 name = "clap"
-version = "4.5.18"
+version = "4.5.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0956a43b323ac1afaffc053ed5c4b7c1f1800bacd1683c353aabbb752515dd3"
+checksum = "ed6719fffa43d0d87e5fd8caeab59be1554fb028cd30edc88fc4369b17971019"
 dependencies = [
 "clap_builder",
 "clap_derive",
@@ -363,9 +336,9 @@ dependencies = [

 [[package]]
 name = "clap_builder"
-version = "4.5.18"
+version = "4.5.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4d72166dd41634086d5803a47eb71ae740e61d84709c36f3c34110173db3961b"
+checksum = "216aec2b177652e3846684cbfe25c9964d18ec45234f0f5da5157b207ed1aab6"
 dependencies = [
 "anstream",
 "anstyle",
@@ -406,9 +379,9 @@ dependencies = [

 [[package]]
 name = "clap_derive"
-version = "4.5.18"
+version = "4.5.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ac6a0c7b1a9e9a5186361f67dfa1b88213572f427fb9ab038efb2bd8c582dab"
+checksum = "501d359d5f3dcaf6ecdeee48833ae73ec6e42723a1e52419c79abf9507eec0a0"
 dependencies = [
 "heck",
 "proc-macro2",
@@ -437,9 +410,9 @@ dependencies = [

 [[package]]
 name = "codspeed"
-version = "2.7.2"
+version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "450a0e9df9df1c154156f4344f99d8f6f6e69d0fc4de96ef6e2e68b2ec3bce97"
+checksum = "3a104ac948e0188b921eb3fcbdd55dcf62e542df4c7ab7e660623f6288302089"
 dependencies = [
 "colored",
 "libc",
@@ -448,9 +421,9 @@ dependencies = [

 [[package]]
 name = "codspeed-criterion-compat"
-version = "2.7.2"
+version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8eb1a6cb9c20e177fde58cdef97c1c7c9264eb1424fe45c4fccedc2fb078a569"
+checksum = "722c36bdc62d9436d027256ce2627af81ac7a596dfc7d13d849d0d212448d7fe"
 dependencies = [
 "codspeed",
 "colored",
@@ -538,15 +511,6 @@ dependencies = [
 "rustc-hash 1.1.0",
 ]

-[[package]]
-name = "cpufeatures"
-version = "0.2.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "51e852e6dc9a5bed1fae92dd2375037bf2b768725bf3be87811edee3249d09ad"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "crc32fast"
 version = "1.4.0"
@@ -652,16 +616,6 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"

-[[package]]
-name = "crypto-common"
-version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
-dependencies = [
- "generic-array",
- "typenum",
-]
-
 [[package]]
 name = "ctrlc"
 version = "3.4.5"
@@ -722,9 +676,9 @@ dependencies = [

 [[package]]
 name = "dashmap"
-version = "6.1.0"
+version = "6.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5041cc499144891f3790297212f32a74fb938e5136a14943f338ef9e0ae276cf"
+checksum = "804c8821570c3f8b70230c2ba75ffa5c0f9a4189b9a432b6656c536712acae28"
 dependencies = [
 "cfg-if",
 "crossbeam-utils",
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- "crypto-common",
-]
-
 [[package]]
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@@ -797,12 +735,6 @@ dependencies = [
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-[[package]]
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-
 [[package]]
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@@ -879,9 +811,9 @@ dependencies = [

 [[package]]
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+checksum = "658bd65b1cf4c852a3cc96f18a8ce7b5640f6b703f905c7d74532294c2a63984"

 [[package]]
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@@ -894,9 +826,9 @@ dependencies = [

 [[package]]
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 dependencies = [
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 "libc",
@@ -947,16 +879,6 @@ dependencies = [
 "libc",
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-[[package]]
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-
 [[package]]
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@@ -987,26 +909,15 @@ checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"

 [[package]]
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-version = "0.4.15"
+version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15f1ce686646e7f1e19bf7d5533fe443a45dbfb990e00629110797578b42fb19"
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 dependencies = [
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 "bstr",
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-[[package]]
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-dependencies = [
- "bitflags 2.6.0",
- "ignore",
- "walkdir",
+ "regex-automata 0.4.6",
+ "regex-syntax 0.8.3",
 ]

 [[package]]
@@ -1106,15 +1017,15 @@ dependencies = [

 [[package]]
 name = "ignore"
-version = "0.4.23"
+version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d89fd380afde86567dfba715db065673989d6253f42b88179abd3eae47bda4b"
+checksum = "b46810df39e66e925525d6e38ce1e7f6e1d208f72dc39757880fcb66e2c58af1"
 dependencies = [
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 "globset",
 "log",
 "memchr",
- "regex-automata 0.4.8",
+ "regex-automata 0.4.6",
 "same-file",
 "walkdir",
 "winapi-util",
@@ -1142,9 +1053,9 @@ dependencies = [

 [[package]]
 name = "indexmap"
-version = "2.5.0"
+version = "2.4.0"
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-checksum = "68b900aa2f7301e21c36462b170ee99994de34dff39a4a6a528e80e7376d07e5"
+checksum = "93ead53efc7ea8ed3cfb0c79fc8023fbb782a5432b52830b6518941cebe6505c"
 dependencies = [
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 "hashbrown",
@@ -1193,16 +1104,14 @@ dependencies = [

 [[package]]
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-version = "1.40.0"
+version = "1.39.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
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+checksum = "810ae6042d48e2c9e9215043563a58a80b877bc863228a74cf10c49d4620a6f5"
 dependencies = [
 "console",
 "globset",
 "lazy_static",
 "linked-hash-map",
- "pest",
- "pest_derive",
 "regex",
 "serde",
 "similar",
@@ -1347,9 +1256,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"

 [[package]]
 name = "libc"
-version = "0.2.159"
+version = "0.2.158"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "561d97a539a36e26a9a5fad1ea11a3039a67714694aaa379433e580854bc3dc5"
+checksum = "d8adc4bb1803a324070e64a98ae98f38934d91957a99cfb3a43dcbc01bc56439"

 [[package]]
 name = "libcst"
@@ -1405,9 +1314,9 @@ checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"

 [[package]]
 name = "linux-raw-sys"
-version = "0.4.14"
+version = "0.4.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78b3ae25bc7c8c38cec158d1f2757ee79e9b3740fbc7ccf0e59e4b08d793fa89"
+checksum = "01cda141df6706de531b6c46c3a33ecca755538219bd484262fa09410c13539c"

 [[package]]
 name = "lock_api"
@@ -1427,9 +1336,9 @@ checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"

 [[package]]
 name = "lsp-server"
-version = "0.7.7"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "550446e84739dcaf6d48a4a093973850669e13e8a34d8f8d64851041be267cd9"
+checksum = "248f65b78f6db5d8e1b1604b4098a28b43d21a8eb1deeca22b1c421b276c7095"
 dependencies = [
 "crossbeam-channel",
 "log",
@@ -1644,9 +1553,9 @@ checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"

 [[package]]
 name = "ordermap"
-version = "0.5.3"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31f2bd7b03bf2c767e1bb7b91505dbe022833776e60480275e6f2fb0db0c7503"
+checksum = "61d7d835be600a7ac71b24e39c92fe6fad9e818b3c71bfc379e3ba65e327d77f"
 dependencies = [
 "indexmap",
 ]
@@ -1798,51 +1707,6 @@ version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"

-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd53dff83f26735fdc1ca837098ccf133605d794cdae66acfc2bfac3ec809d95"
-dependencies = [
- "memchr",
- "thiserror",
- "ucd-trie",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a548d2beca6773b1c244554d36fcf8548a8a58e74156968211567250e48e49a"
-dependencies = [
- "pest",
- "pest_generator",
-]
-
-[[package]]
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-version = "2.7.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3c93a82e8d145725dcbaf44e5ea887c8a869efdcc28706df2d08c69e17077183"
-dependencies = [
- "pest",
- "pest_meta",
- "proc-macro2",
- "quote",
- "syn",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
- "once_cell",
- "pest",
- "sha2",
-]
-
 [[package]]
 name = "phf"
 version = "0.11.2"
@@ -1905,38 +1769,11 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"

-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
- "anstyle",
- "difflib",
- "predicates-core",
-]
-
-[[package]]
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-version = "1.0.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae8177bee8e75d6846599c6b9ff679ed51e882816914eec639944d7c9aa11931"
-
-[[package]]
-name = "predicates-tree"
-version = "1.0.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41b740d195ed3166cd147c8047ec98db0e22ec019eb8eeb76d343b795304fb13"
-dependencies = [
- "predicates-core",
- "termtree",
-]
-
 [[package]]
 name = "pretty_assertions"
-version = "1.4.1"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ae130e2f271fbc2ac3a40fb1d07180839cdbbe443c7a27e1e3c13c5cac0116d"
+checksum = "af7cee1a6c8a5b9208b3cb1061f10c0cb689087b3d8ce85fb9d2dd7a29b6ba66"
 dependencies = [
 "diff",
 "yansi",
@@ -2083,8 +1920,9 @@ dependencies = [
 "countme",
 "hashbrown",
 "insta",
+ "once_cell",
 "ordermap",
- "red_knot_vendored",
+ "path-slash",
 "ruff_db",
 "ruff_index",
 "ruff_python_ast",
@@ -2098,9 +1936,10 @@ dependencies = [
 "smallvec",
 "static_assertions",
 "tempfile",
- "test-case",
 "thiserror",
 "tracing",
+ "walkdir",
+ "zip",
 ]

 [[package]]
@@ -2127,17 +1966,6 @@ dependencies = [
 "tracing-subscriber",
 ]

-[[package]]
-name = "red_knot_vendored"
-version = "0.0.0"
-dependencies = [
- "once_cell",
- "path-slash",
- "ruff_db",
- "walkdir",
- "zip",
-]
-
 [[package]]
 name = "red_knot_wasm"
 version = "0.0.0"
@@ -2163,7 +1991,6 @@ dependencies = [
 "notify",
 "rayon",
 "red_knot_python_semantic",
- "red_knot_vendored",
 "ruff_cache",
 "ruff_db",
 "ruff_python_ast",
@@ -2205,14 +2032,14 @@ dependencies = [

 [[package]]
 name = "regex"
-version = "1.11.0"
+version = "1.10.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38200e5ee88914975b69f657f0801b6f6dccafd44fd9326302a4aaeecfacb1d8"
+checksum = "4219d74c6b67a3654a9fbebc4b419e22126d13d2f3c4a07ee0cb61ff79a79619"
 dependencies = [
 "aho-corasick",
 "memchr",
- "regex-automata 0.4.8",
- "regex-syntax 0.8.5",
+ "regex-automata 0.4.6",
+ "regex-syntax 0.8.3",
 ]

 [[package]]
@@ -2226,13 +2053,13 @@ dependencies = [

 [[package]]
 name = "regex-automata"
-version = "0.4.8"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "368758f23274712b504848e9d5a6f010445cc8b87a7cdb4d7cbee666c1288da3"
+checksum = "86b83b8b9847f9bf95ef68afb0b8e6cdb80f498442f5179a29fad448fcc1eaea"
 dependencies = [
 "aho-corasick",
 "memchr",
- "regex-syntax 0.8.5",
+ "regex-syntax 0.8.3",
 ]

 [[package]]
@@ -2243,9 +2070,9 @@ checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"

 [[package]]
 name = "regex-syntax"
-version = "0.8.5"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
+checksum = "adad44e29e4c806119491a7f06f03de4d1af22c3a680dd47f1e6e179439d1f56"

 [[package]]
 name = "ring"
@@ -2264,11 +2091,10 @@ dependencies = [

 [[package]]
 name = "ruff"
-version = "0.6.9"
+version = "0.6.3"
 dependencies = [
 "anyhow",
 "argfile",
- "assert_fs",
 "bincode",
 "bitflags 2.6.0",
 "cachedir",
@@ -2278,9 +2104,7 @@ dependencies = [
 "clearscreen",
 "colored",
 "filetime",
- "globwalk",
 "ignore",
- "indoc",
 "insta",
 "insta-cmd",
 "is-macro",
@@ -2292,9 +2116,7 @@ dependencies = [
 "rayon",
 "regex",
 "ruff_cache",
- "ruff_db",
 "ruff_diagnostics",
- "ruff_graph",
 "ruff_linter",
 "ruff_macros",
 "ruff_notebook",
@@ -2336,7 +2158,6 @@ dependencies = [
 "ruff_python_formatter",
 "ruff_python_parser",
 "ruff_python_trivia",
- "rustc-hash 2.0.0",
 "serde",
 "serde_json",
 "tikv-jemallocator",
@@ -2363,7 +2184,7 @@ version = "0.0.0"
 dependencies = [
 "camino",
 "countme",
- "dashmap 6.1.0",
+ "dashmap 6.0.1",
 "filetime",
 "ignore",
 "insta",
@@ -2378,7 +2199,6 @@ dependencies = [
 "ruff_text_size",
 "rustc-hash 2.0.0",
 "salsa",
- "serde",
 "tempfile",
 "thiserror",
 "tracing",
@@ -2454,26 +2274,6 @@ dependencies = [
 "unicode-width",
 ]

-[[package]]
-name = "ruff_graph"
-version = "0.1.0"
-dependencies = [
- "anyhow",
- "clap",
- "once_cell",
- "red_knot_python_semantic",
- "ruff_cache",
- "ruff_db",
- "ruff_linter",
- "ruff_macros",
- "ruff_python_ast",
- "ruff_python_parser",
- "salsa",
- "schemars",
- "serde",
- "zip",
-]
-
 [[package]]
 name = "ruff_index"
 version = "0.0.0"
@@ -2484,7 +2284,7 @@ dependencies = [

 [[package]]
 name = "ruff_linter"
-version = "0.6.9"
+version = "0.6.3"
 dependencies = [
 "aho-corasick",
 "annotate-snippets 0.9.2",
@@ -2804,7 +2604,7 @@ dependencies = [

 [[package]]
 name = "ruff_wasm"
-version = "0.6.9"
+version = "0.6.3"
 dependencies = [
 "console_error_panic_hook",
 "console_log",
@@ -2847,7 +2647,6 @@ dependencies = [
 "regex",
 "ruff_cache",
 "ruff_formatter",
- "ruff_graph",
 "ruff_linter",
 "ruff_macros",
 "ruff_python_ast",
@@ -2887,9 +2686,9 @@ checksum = "583034fd73374156e66797ed8e5b0d5690409c9226b22d87cb7f19821c05d152"

 [[package]]
 name = "rustix"
-version = "0.38.37"
+version = "0.38.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8acb788b847c24f28525660c4d7758620a7210875711f79e7f663cc152726811"
+checksum = "70dc5ec042f7a43c4a73241207cecc9873a06d45debb38b329f8541d85c2730f"
 dependencies = [
 "bitflags 2.6.0",
 "errno",
@@ -2945,12 +2744,12 @@ checksum = "e86697c916019a8588c99b5fac3cead74ec0b4b819707a682fd4d23fa0ce1ba1"
 [[package]]
 name = "salsa"
 version = "0.18.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=4a7c955255e707e64e43f3ce5eabb771ae067768#4a7c955255e707e64e43f3ce5eabb771ae067768"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"
 dependencies = [
 "append-only-vec",
 "arc-swap",
 "crossbeam",
- "dashmap 6.1.0",
+ "dashmap 6.0.1",
 "hashlink",
 "indexmap",
 "lazy_static",
@@ -2965,12 +2764,12 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.1.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=4a7c955255e707e64e43f3ce5eabb771ae067768#4a7c955255e707e64e43f3ce5eabb771ae067768"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"

 [[package]]
 name = "salsa-macros"
 version = "0.18.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=4a7c955255e707e64e43f3ce5eabb771ae067768#4a7c955255e707e64e43f3ce5eabb771ae067768"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=f608ff8b24f07706492027199f51132244034f29#f608ff8b24f07706492027199f51132244034f29"
 dependencies = [
 "heck",
 "proc-macro2",
@@ -3032,9 +2831,9 @@ checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"

 [[package]]
 name = "serde"
-version = "1.0.210"
+version = "1.0.209"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8e3592472072e6e22e0a54d5904d9febf8508f65fb8552499a1abc7d1078c3a"
+checksum = "99fce0ffe7310761ca6bf9faf5115afbc19688edd00171d81b1bb1b116c63e09"
 dependencies = [
 "serde_derive",
 ]
@@ -3052,9 +2851,9 @@ dependencies = [

 [[package]]
 name = "serde_derive"
-version = "1.0.210"
+version = "1.0.209"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
+checksum = "a5831b979fd7b5439637af1752d535ff49f4860c0f341d1baeb6faf0f4242170"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -3074,9 +2873,9 @@ dependencies = [

 [[package]]
 name = "serde_json"
-version = "1.0.128"
+version = "1.0.127"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ff5456707a1de34e7e37f2a6fd3d3f808c318259cbd01ab6377795054b483d8"
+checksum = "8043c06d9f82bd7271361ed64f415fe5e12a77fdb52e573e7f06a516dea329ad"
 dependencies = [
 "itoa",
 "memchr",
@@ -3136,17 +2935,6 @@ dependencies = [
 "syn",
 ]

-[[package]]
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-version = "0.10.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
- "cfg-if",
- "cpufeatures",
- "digest",
-]
-
 [[package]]
 name = "sharded-slab"
 version = "0.1.7"
@@ -3246,9 +3034,9 @@ checksum = "81cdd64d312baedb58e21336b31bc043b77e01cc99033ce76ef539f78e965ebc"

 [[package]]
 name = "syn"
-version = "2.0.79"
+version = "2.0.76"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89132cd0bf050864e1d38dc3bbc07a0eb8e7530af26344d3d2bbbef83499f590"
+checksum = "578e081a14e0cefc3279b0472138c513f37b41a08d5a3cca9b6e4e8ceb6cd525"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -3268,9 +3056,9 @@ dependencies = [

 [[package]]
 name = "tempfile"
-version = "3.13.0"
+version = "3.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0f2c9fc62d0beef6951ccffd757e241266a2c833136efbe35af6cd2567dca5b"
+checksum = "04cbcdd0c794ebb0d4cf35e88edd2f7d2c4c3e9a5a6dab322839b321c6a87a64"
 dependencies = [
 "cfg-if",
 "fastrand",
@@ -3302,12 +3090,6 @@ dependencies = [
 "phf_codegen",
 ]

-[[package]]
-name = "termtree"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3369f5ac52d5eb6ab48c6b4ffdc8efbcad6b89c765749064ba298f2c68a16a76"
-
 [[package]]
 name = "test-case"
 version = "3.3.1"
@@ -3343,18 +3125,18 @@ dependencies = [

 [[package]]
 name = "thiserror"
-version = "1.0.64"
+version = "1.0.63"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d50af8abc119fb8bb6dbabcfa89656f46f84aa0ac7688088608076ad2b459a84"
+checksum = "c0342370b38b6a11b6cc11d6a805569958d54cfa061a29969c3b5ce2ea405724"
 dependencies = [
 "thiserror-impl",
 ]

 [[package]]
 name = "thiserror-impl"
-version = "1.0.64"
+version = "1.0.63"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08904e7672f5eb876eaaf87e0ce17857500934f4981c4a0ab2b4aa98baac7fc3"
+checksum = "a4558b58466b9ad7ca0f102865eccc95938dca1a74a856f2b57b6629050da261"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -3553,18 +3335,6 @@ version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6af6ae20167a9ece4bcb41af5b80f8a1f1df981f6391189ce00fd257af04126a"

-[[package]]
-name = "typenum"
-version = "1.17.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
-
-[[package]]
-name = "ucd-trie"
-version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed646292ffc8188ef8ea4d1e0e0150fb15a5c2e12ad9b8fc191ae7a8a7f3c4b9"
-
 [[package]]
 name = "unic-char-property"
 version = "0.9.0"
@@ -3615,15 +3385,15 @@ checksum = "08f95100a766bf4f8f28f90d77e0a5461bbdb219042e7679bebe79004fed8d75"

 [[package]]
 name = "unicode-ident"
-version = "1.0.13"
+version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"

 [[package]]
 name = "unicode-normalization"
-version = "0.1.24"
+version = "0.1.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5033c97c4262335cded6d6fc3e5c18ab755e1a3dc96376350f3d8e9f009ad956"
+checksum = "a56d1686db2308d901306f92a263857ef59ea39678a5458e7cb17f01415101f5"
 dependencies = [
 "tinyvec",
 ]
@@ -3636,9 +3406,9 @@ checksum = "0336d538f7abc86d282a4189614dfaa90810dfc2c6f6427eaf88e16311dd225d"

 [[package]]
 name = "unicode_names2"
-version = "1.3.0"
+version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1673eca9782c84de5f81b82e4109dcfb3611c8ba0d52930ec4a9478f547b2dd"
+checksum = "addeebf294df7922a1164f729fb27ebbbcea99cc32b3bf08afab62757f707677"
 dependencies = [
 "phf",
 "unicode_names2_generator",
@@ -3646,9 +3416,9 @@ dependencies = [

 [[package]]
 name = "unicode_names2_generator"
-version = "1.3.0"
+version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b91e5b84611016120197efd7dc93ef76774f4e084cd73c9fb3ea4a86c570c56e"
+checksum = "f444b8bba042fe3c1251ffaca35c603f2dc2ccc08d595c65a8c4f76f3e8426c0"
 dependencies = [
 "getopts",
 "log",
@@ -4134,9 +3904,9 @@ checksum = "d135d17ab770252ad95e9a872d365cf3090e3be864a34ab46f48555993efc904"

 [[package]]
 name = "yansi"
-version = "1.0.1"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfe53a6657fd280eaa890a3bc59152892ffa3e30101319d168b781ed6529b049"
+checksum = "09041cd90cf85f7f8b2df60c646f853b7f535ce68f85244eb6731cf89fa498ec"

 [[package]]
 name = "yansi-term"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,10 +14,9 @@ license = "MIT"
 [workspace.dependencies]
 ruff = { path = "crates/ruff" }
 ruff_cache = { path = "crates/ruff_cache" }
-ruff_db = { path = "crates/ruff_db", default-features = false }
+ruff_db = { path = "crates/ruff_db" }
 ruff_diagnostics = { path = "crates/ruff_diagnostics" }
 ruff_formatter = { path = "crates/ruff_formatter" }
-ruff_graph = { path = "crates/ruff_graph" }
 ruff_index = { path = "crates/ruff_index" }
 ruff_linter = { path = "crates/ruff_linter" }
 ruff_macros = { path = "crates/ruff_macros" }
@@ -34,17 +33,15 @@ ruff_python_trivia = { path = "crates/ruff_python_trivia" }
 ruff_server = { path = "crates/ruff_server" }
 ruff_source_file = { path = "crates/ruff_source_file" }
 ruff_text_size = { path = "crates/ruff_text_size" }
-red_knot_vendored = { path = "crates/red_knot_vendored" }
 ruff_workspace = { path = "crates/ruff_workspace" }

 red_knot_python_semantic = { path = "crates/red_knot_python_semantic" }
 red_knot_server = { path = "crates/red_knot_server" }
-red_knot_workspace = { path = "crates/red_knot_workspace", default-features = false }
+red_knot_workspace = { path = "crates/red_knot_workspace" }

 aho-corasick = { version = "1.1.3" }
 annotate-snippets = { version = "0.9.2", features = ["color"] }
 anyhow = { version = "1.0.80" }
-assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
 bincode = { version = "1.3.3" }
 bitflags = { version = "2.5.0" }
@@ -71,7 +68,6 @@ fern = { version = "0.6.1" }
 filetime = { version = "0.2.23" }
 glob = { version = "0.3.1" }
 globset = { version = "0.4.14" }
-globwalk = { version = "0.9.1" }
 hashbrown = "0.14.3"
 ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
@@ -112,7 +108,7 @@ rand = { version = "0.8.5" }
 rayon = { version = "1.10.0" }
 regex = { version = "1.10.2" }
 rustc-hash = { version = "2.0.0" }
-salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "4a7c955255e707e64e43f3ce5eabb771ae067768" }
+salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "f608ff8b24f07706492027199f51132244034f29" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
@@ -234,9 +230,9 @@ inherits = "release"
 # Config for 'cargo dist'
 [workspace.metadata.dist]
 # The preferred cargo-dist version to use in CI (Cargo.toml SemVer syntax)
-cargo-dist-version = "0.22.1"
+cargo-dist-version = "0.18.0"
 # CI backends to support
-ci = "github"
+ci = ["github"]
 # The installers to generate for each app
 installers = ["shell", "powershell"]
 # The archive format to use for windows builds (defaults .zip)
@@ -267,11 +263,11 @@ targets = [
 auto-includes = false
 # Whether cargo-dist should create a GitHub Release or use an existing draft
 create-release = true
-# Which actions to run on pull requests
+# Publish jobs to run in CI
 pr-run-mode = "skip"
 # Whether CI should trigger releases with dispatches instead of tag pushes
 dispatch-releases = true
-# Which phase cargo-dist should use to create the GitHub release
+# The stage during which the GitHub Release should be created
 github-release = "announce"
 # Whether CI should include auto-generated code to build local artifacts
 build-local-artifacts = false
@@ -279,11 +275,9 @@ build-local-artifacts = false
 local-artifacts-jobs = ["./build-binaries", "./build-docker"]
 # Publish jobs to run in CI
 publish-jobs = ["./publish-pypi", "./publish-wasm"]
-# Post-announce jobs to run in CI
+# Announcement jobs to run in CI
 post-announce-jobs = ["./notify-dependents", "./publish-docs", "./publish-playground"]
 # Custom permissions for GitHub Jobs
 github-custom-job-permissions = { "build-docker" = { packages = "write", contents = "read" }, "publish-wasm" = { contents = "read", id-token = "write", packages = "write" } }
 # Whether to install an updater program
 install-updater = false
-# Path that installers should place binaries in
-install-path = "CARGO_HOME"
--- a/README.md
+++ b/README.md
@@ -136,8 +136,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"

 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.6.9/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.6.9/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.6.3/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.6.3/install.ps1 | iex"
 ```

 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -170,7 +170,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
  # Ruff version.
-  rev: v0.6.9
+  rev: v0.6.3
  hooks:
    # Run the linter.
    - id: ruff
@@ -182,7 +182,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 Ruff can also be used as a [VS Code extension](https://github.com/astral-sh/ruff-vscode) or with [various other editors](https://docs.astral.sh/ruff/editors/setup).

 Ruff can also be used as a [GitHub Action](https://github.com/features/actions) via
-[`ruff-action`](https://github.com/astral-sh/ruff-action):
+[`ruff-action`](https://github.com/chartboost/ruff-action):

 ```yaml
 name: Ruff
@@ -192,7 +192,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
-      - uses: astral-sh/ruff-action@v1
+      - uses: chartboost/ruff-action@v1
 ```

 ### Configuration<a id="configuration"></a>
--- a/_typos.toml
+++ b/_typos.toml
@@ -1,6 +1,6 @@
 [files]
 # https://github.com/crate-ci/typos/issues/868
-extend-exclude = ["crates/red_knot_vendored/vendor/**/*", "**/resources/**/*", "**/snapshots/**/*"]
+extend-exclude = ["crates/red_knot_python_semantic/vendor/**/*", "**/resources/**/*", "**/snapshots/**/*"]

 [default.extend-words]
 "arange" = "arange"  # e.g. `numpy.arange`
@@ -8,7 +8,7 @@ hel = "hel"
 whos = "whos"
 spawnve = "spawnve"
 ned = "ned"
-pn = "pn"  # `import panel as pn` is a thing
+pn = "pn"  # `import panel as pd` is a thing
 poit = "poit"
 BA = "BA" # acronym for "Bad Allowed", used in testing.
 jod = "jod" # e.g., `jod-thread`
--- a/crates/red_knot/Cargo.toml
+++ b/crates/red_knot/Cargo.toml
@@ -13,8 +13,9 @@ license.workspace = true

 [dependencies]
 red_knot_python_semantic = { workspace = true }
-red_knot_workspace = { workspace = true, features = ["zstd"] }
+red_knot_workspace = { workspace = true }
 red_knot_server = { workspace = true }
+
 ruff_db = { workspace = true, features = ["os", "cache"] }

 anyhow = { workspace = true }
--- a/crates/red_knot/src/main.rs
+++ b/crates/red_knot/src/main.rs
@@ -160,7 +160,7 @@ fn run() -> anyhow::Result<ExitStatus> {
        SystemPathBuf::from_path_buf(cwd)
            .map_err(|path| {
                anyhow!(
-                    "The current working directory `{}` contains non-Unicode characters. Red Knot only supports Unicode paths.",
+                    "The current working directory '{}' contains non-unicode characters. Red Knot only supports unicode paths.",
                    path.display()
                )
            })?
@@ -174,7 +174,7 @@ fn run() -> anyhow::Result<ExitStatus> {
                Ok(SystemPath::absolute(cwd, &cli_base_path))
            } else {
                Err(anyhow!(
-                    "Provided current-directory path `{cwd}` is not a directory"
+                    "Provided current-directory path '{cwd}' is not a directory."
                ))
            }
        })
--- a/crates/red_knot/tests/file_watching.rs
+++ b/crates/red_knot/tests/file_watching.rs
@@ -42,14 +42,14 @@ impl TestCase {

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

    fn try_stop_watch(&mut self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
        let watcher = self
            .watcher
            .take()
-            .expect("Cannot call `stop_watch` more than once");
+            .expect("Cannot call `stop_watch` more than once.");

        let mut all_events = self
            .changes_receiver
@@ -72,7 +72,7 @@ impl TestCase {
    #[cfg(unix)]
    fn take_watch_changes(&self) -> Vec<watch::ChangeEvent> {
        self.try_take_watch_changes(Duration::from_secs(10))
-            .expect("Expected watch changes but observed none")
+            .expect("Expected watch changes but observed none.")
    }

    fn try_take_watch_changes(&self, timeout: Duration) -> Option<Vec<watch::ChangeEvent>> {
@@ -150,14 +150,14 @@ where
            let absolute_path = workspace_path.join(relative_path);
            if let Some(parent) = absolute_path.parent() {
                std::fs::create_dir_all(parent).with_context(|| {
-                    format!("Failed to create parent directory for file `{relative_path}`")
+                    format!("Failed to create parent directory for file '{relative_path}'.",)
                })?;
            }

            let mut file = std::fs::File::create(absolute_path.as_std_path())
-                .with_context(|| format!("Failed to open file `{relative_path}`"))?;
+                .with_context(|| format!("Failed to open file '{relative_path}'"))?;
            file.write_all(content.as_bytes())
-                .with_context(|| format!("Failed to write to file `{relative_path}`"))?;
+                .with_context(|| format!("Failed to write to file '{relative_path}'"))?;
            file.sync_data()?;
        }

@@ -194,7 +194,7 @@ where

    let root_path = SystemPath::from_std_path(temp_dir.path()).ok_or_else(|| {
        anyhow!(
-            "Temporary directory `{}` is not a valid UTF-8 path.",
+            "Temp directory '{}' is not a valid UTF-8 path.",
            temp_dir.path().display()
        )
    })?;
@@ -209,7 +209,7 @@ where
    let workspace_path = root_path.join("workspace");

    std::fs::create_dir_all(workspace_path.as_std_path())
-        .with_context(|| format!("Failed to create workspace directory `{workspace_path}`"))?;
+        .with_context(|| format!("Failed to create workspace directory '{workspace_path}'",))?;

    setup_files
        .setup(&root_path, &workspace_path)
@@ -233,7 +233,7 @@ where
        }))
    {
        std::fs::create_dir_all(path.as_std_path())
-            .with_context(|| format!("Failed to create search path `{path}`"))?;
+            .with_context(|| format!("Failed to create search path '{path}'"))?;
    }

    let configuration = Configuration {
@@ -665,7 +665,7 @@ fn directory_deleted() -> anyhow::Result<()> {

    let bar = case.system_file(case.workspace_path("bar.py")).unwrap();

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

    let sub_path = case.workspace_path("sub");

--- a/crates/red_knot_python_semantic/Cargo.toml
+++ b/crates/red_knot_python_semantic/Cargo.toml
@@ -24,6 +24,7 @@ bitflags = { workspace = true }
 camino = { workspace = true }
 compact_str = { workspace = true }
 countme = { workspace = true }
+once_cell = { workspace = true }
 ordermap = { workspace = true }
 salsa = { workspace = true }
 thiserror = { workspace = true }
@@ -32,16 +33,21 @@ rustc-hash = { workspace = true }
 hashbrown = { workspace = true }
 smallvec = { workspace = true }
 static_assertions = { workspace = true }
-test-case = { workspace = true }
+
+[build-dependencies]
+path-slash = { workspace = true }
+walkdir = { workspace = true }
+zip = { workspace = true, features = ["zstd", "deflate"] }

 [dev-dependencies]
 ruff_db = { workspace = true, features = ["os", "testing"] }
 ruff_python_parser = { workspace = true }
-red_knot_vendored = { workspace = true }

 anyhow = { workspace = true }
 insta = { workspace = true }
 tempfile = { workspace = true }
+walkdir = { workspace = true }
+zip = { workspace = true }

 [lints]
 workspace = true
--- a/crates/red_knot_python_semantic/README.md
+++ b/crates/red_knot_python_semantic/README.md
@@ -1,5 +1,9 @@
-# Vendored types for the stdlib
+# Red Knot

-This crate vendors [typeshed](https://github.com/python/typeshed)'s stubs for the standard library. The vendored stubs can be found in `crates/red_knot_vendored/vendor/typeshed`. The file `crates/red_knot_vendored/vendor/typeshed/source_commit.txt` tells you the typeshed commit that our vendored stdlib stubs currently correspond to.
+Semantic analysis for the red-knot project.
+
+## Vendored types for the stdlib
+
+This crate vendors [typeshed](https://github.com/python/typeshed)'s stubs for the standard library. The vendored stubs can be found in `crates/red_knot_python_semantic/vendor/typeshed`. The file `crates/red_knot_python_semantic/vendor/typeshed/source_commit.txt` tells you the typeshed commit that our vendored stdlib stubs currently correspond to.

 The typeshed stubs are updated every two weeks via an automated PR using the `sync_typeshed.yaml` workflow in the `.github/workflows` directory. This workflow can also be triggered at any time via [workflow dispatch](https://docs.github.com/en/actions/using-workflows/manually-running-a-workflow#running-a-workflow).
--- a/crates/red_knot_python_semantic/build.rs
+++ b/crates/red_knot_python_semantic/build.rs
@@ -3,7 +3,7 @@
 //!
 //! This script should be automatically run at build time
 //! whenever the script itself changes, or whenever any files
-//! in `crates/red_knot_vendored/vendor/typeshed` change.
+//! in `crates/red_knot_python_semantic/vendor/typeshed` change.

 use std::fs::File;
 use std::path::Path;
@@ -30,12 +30,10 @@ fn zip_dir(directory_path: &str, writer: File) -> ZipResult<File> {
    // We can't use `#[cfg(...)]` here because the target-arch in a build script is the
    // architecture of the system running the build script and not the architecture of the build-target.
    // That's why we use the `TARGET` environment variable here.
-    let method = if cfg!(feature = "zstd") {
-        CompressionMethod::Zstd
-    } else if cfg!(feature = "deflate") {
+    let method = if std::env::var("TARGET").unwrap().contains("wasm32") {
        CompressionMethod::Deflated
    } else {
-        CompressionMethod::Stored
+        CompressionMethod::Zstd
    };

    let options = FileOptions::default()
--- a/crates/red_knot_python_semantic/src/builtins.rs
+++ b/crates/red_knot_python_semantic/src/builtins.rs
@@ -0,0 +1,16 @@
+use crate::module_name::ModuleName;
+use crate::module_resolver::resolve_module;
+use crate::semantic_index::global_scope;
+use crate::semantic_index::symbol::ScopeId;
+use crate::Db;
+
+/// Salsa query to get the builtins scope.
+///
+/// Can return None if a custom typeshed is used that is missing `builtins.pyi`.
+#[salsa::tracked]
+pub(crate) fn builtins_scope(db: &dyn Db) -> Option<ScopeId<'_>> {
+    let builtins_name =
+        ModuleName::new_static("builtins").expect("Expected 'builtins' to be a valid module name");
+    let builtins_file = resolve_module(db, builtins_name)?.file();
+    Some(global_scope(db, builtins_file))
+}
--- a/crates/red_knot_python_semantic/src/db.rs
+++ b/crates/red_knot_python_semantic/src/db.rs
@@ -11,6 +11,7 @@ pub trait Db: SourceDb + Upcast<dyn SourceDb> {
 pub(crate) mod tests {
    use std::sync::Arc;

+    use crate::module_resolver::vendored_typeshed_stubs;
    use ruff_db::files::{File, Files};
    use ruff_db::system::{DbWithTestSystem, System, TestSystem};
    use ruff_db::vendored::VendoredFileSystem;
@@ -32,7 +33,7 @@ pub(crate) mod tests {
            Self {
                storage: salsa::Storage::default(),
                system: TestSystem::default(),
-                vendored: red_knot_vendored::file_system().clone(),
+                vendored: vendored_typeshed_stubs().clone(),
                events: std::sync::Arc::default(),
                files: Files::default(),
            }
--- a/crates/red_knot_python_semantic/src/lib.rs
+++ b/crates/red_knot_python_semantic/src/lib.rs
@@ -4,12 +4,13 @@ use rustc_hash::FxHasher;

 pub use db::Db;
 pub use module_name::ModuleName;
-pub use module_resolver::{resolve_module, system_module_search_paths, Module};
+pub use module_resolver::{resolve_module, system_module_search_paths, vendored_typeshed_stubs};
 pub use program::{Program, ProgramSettings, SearchPathSettings, SitePackages};
 pub use python_version::PythonVersion;
 pub use semantic_model::{HasTy, SemanticModel};

 pub mod ast_node_ref;
+mod builtins;
 mod db;
 mod module_name;
 mod module_resolver;
@@ -19,7 +20,7 @@ mod python_version;
 pub mod semantic_index;
 mod semantic_model;
 pub(crate) mod site_packages;
-mod stdlib;
 pub mod types;

 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;
+type FxOrderMap<K, V> = ordermap::map::OrderMap<K, V, BuildHasherDefault<FxHasher>>;
--- a/crates/red_knot_python_semantic/src/module_resolver/mod.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/mod.rs
@@ -1,9 +1,10 @@
 use std::iter::FusedIterator;

-pub use module::Module;
+pub(crate) use module::Module;
 pub use resolver::resolve_module;
 pub(crate) use resolver::{file_to_module, SearchPaths};
 use ruff_db::system::SystemPath;
+pub use typeshed::vendored_typeshed_stubs;

 use crate::module_resolver::resolver::search_paths;
 use crate::Db;
--- a/crates/red_knot_python_semantic/src/module_resolver/path.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/path.rs
@@ -59,10 +59,6 @@ impl ModulePath {
        self.relative_path.push(component);
    }

-    pub(crate) fn pop(&mut self) -> bool {
-        self.relative_path.pop()
-    }
-
    #[must_use]
    pub(super) fn is_directory(&self, resolver: &ResolverContext) -> bool {
        let ModulePath {
--- a/crates/red_knot_python_semantic/src/module_resolver/resolver.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/resolver.rs
@@ -1,21 +1,20 @@
+use rustc_hash::{FxBuildHasher, FxHashSet};
 use std::borrow::Cow;
 use std::iter::FusedIterator;
-
-use rustc_hash::{FxBuildHasher, FxHashSet};
+use std::ops::Deref;

 use ruff_db::files::{File, FilePath, FileRootKind};
 use ruff_db::system::{DirectoryEntry, System, SystemPath, SystemPathBuf};
 use ruff_db::vendored::{VendoredFileSystem, VendoredPath};

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

-use super::module::{Module, ModuleKind};
-use super::path::{ModulePath, SearchPath, SearchPathValidationError};
-
 /// Resolves a module name to a module.
 pub fn resolve_module(db: &dyn Db, module_name: ModuleName) -> Option<Module> {
    let interned_name = ModuleNameIngredient::new(db, module_name);
@@ -36,14 +35,14 @@ pub(crate) fn resolve_module_query<'db>(
    let _span = tracing::trace_span!("resolve_module", %name).entered();

    let Some((search_path, module_file, kind)) = resolve_name(db, name) else {
-        tracing::debug!("Module `{name}` not found in search paths");
+        tracing::debug!("Module '{name}' not found in the search paths.");
        return None;
    };

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

    tracing::trace!(
-        "Resolved module `{name}` to `{path}`",
+        "Resolved module '{name}' to '{path}'.",
        path = module_file.path(db)
    );

@@ -137,7 +136,7 @@ pub(crate) struct SearchPaths {
    /// for the first `site-packages` path
    site_packages: Vec<SearchPath>,

-    typeshed_versions: TypeshedVersions,
+    typeshed_versions: ResolvedTypeshedVersions,
 }

 impl SearchPaths {
@@ -203,11 +202,11 @@ impl SearchPaths {

            let search_path = SearchPath::custom_stdlib(db, &custom_typeshed)?;

-            (parsed, search_path)
+            (ResolvedTypeshedVersions::Custom(parsed), search_path)
        } else {
            tracing::debug!("Using vendored stdlib");
            (
-                vendored_typeshed_versions(db),
+                ResolvedTypeshedVersions::Vendored(vendored_typeshed_versions()),
                SearchPath::vendored_stdlib(),
            )
        };
@@ -280,6 +279,23 @@ impl SearchPaths {
    }
 }

+#[derive(Debug, PartialEq, Eq)]
+enum ResolvedTypeshedVersions {
+    Vendored(&'static TypeshedVersions),
+    Custom(TypeshedVersions),
+}
+
+impl Deref for ResolvedTypeshedVersions {
+    type Target = TypeshedVersions;
+
+    fn deref(&self) -> &Self::Target {
+        match self {
+            ResolvedTypeshedVersions::Vendored(versions) => versions,
+            ResolvedTypeshedVersions::Custom(versions) => versions,
+        }
+    }
+}
+
 /// Collect all dynamic search paths. For each `site-packages` path:
 /// - Collect that `site-packages` path
 /// - Collect any search paths listed in `.pth` files in that `site-packages` directory
@@ -324,7 +340,7 @@ pub(crate) fn dynamic_resolution_paths(db: &dyn Db) -> Vec<SearchPath> {

        let site_packages_root = files
            .root(db.upcast(), site_packages_dir)
-            .expect("Site-package root to have been created");
+            .expect("Site-package root to have been created.");

        // This query needs to be re-executed each time a `.pth` file
        // is added, modified or removed from the `site-packages` directory.
@@ -553,16 +569,24 @@ fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, Mod

                package_path.push(module_name);

-                // Check for a regular package first (highest priority)
-                package_path.push("__init__");
-                if let Some(regular_package) = resolve_file_module(&package_path, &resolver_state) {
-                    return Some((search_path.clone(), regular_package, ModuleKind::Package));
+                // Must be a `__init__.pyi` or `__init__.py` or it isn't a package.
+                let kind = if package_path.is_directory(&resolver_state) {
+                    package_path.push("__init__");
+                    ModuleKind::Package
+                } else {
+                    ModuleKind::Module
+                };
+
+                // TODO Implement full https://peps.python.org/pep-0561/#type-checker-module-resolution-order resolution
+                if let Some(stub) = package_path.with_pyi_extension().to_file(&resolver_state) {
+                    return Some((search_path.clone(), stub, kind));
                }

-                // Check for a file module next
-                package_path.pop();
-                if let Some(file_module) = resolve_file_module(&package_path, &resolver_state) {
-                    return Some((search_path.clone(), file_module, ModuleKind::Module));
+                if let Some(module) = package_path
+                    .with_py_extension()
+                    .and_then(|path| path.to_file(&resolver_state))
+                {
+                    return Some((search_path.clone(), module, kind));
                }

                // For regular packages, don't search the next search path. All files of that
@@ -583,23 +607,6 @@ fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, Mod
    None
 }

-/// If `module` exists on disk with either a `.pyi` or `.py` extension,
-/// return the [`File`] corresponding to that path.
-///
-/// `.pyi` files take priority, as they always have priority when
-/// resolving modules.
-fn resolve_file_module(module: &ModulePath, resolver_state: &ResolverContext) -> Option<File> {
-    // Stubs have precedence over source files
-    module
-        .with_pyi_extension()
-        .to_file(resolver_state)
-        .or_else(|| {
-            module
-                .with_py_extension()
-                .and_then(|path| path.to_file(resolver_state))
-        })
-}
-
 fn resolve_package<'a, 'db, I>(
    module_search_path: &SearchPath,
    components: I,
@@ -626,10 +633,7 @@ where

        if is_regular_package {
            in_namespace_package = false;
-        } else if package_path.is_directory(resolver_state)
-            // Pure modules hide namespace packages with the same name
-            && resolve_file_module(&package_path, resolver_state).is_none()
-        {
+        } else if package_path.is_directory(resolver_state) {
            // A directory without an `__init__.py` is a namespace package, continue with the next folder.
            in_namespace_package = true;
        } else if in_namespace_package {
@@ -1087,25 +1091,6 @@ mod tests {
        );
    }

-    #[test]
-    fn single_file_takes_priority_over_namespace_package() {
-        //const SRC: &[FileSpec] = &[("foo.py", "x = 1")];
-        const SRC: &[FileSpec] = &[("foo.py", "x = 1"), ("foo/bar.py", "x = 2")];
-
-        let TestCase { db, src, .. } = TestCaseBuilder::new().with_src_files(SRC).build();
-
-        let foo_module_name = ModuleName::new_static("foo").unwrap();
-        let foo_bar_module_name = ModuleName::new_static("foo.bar").unwrap();
-
-        // `foo.py` takes priority over the `foo` namespace package
-        let foo_module = resolve_module(&db, foo_module_name.clone()).unwrap();
-        assert_eq!(foo_module.file().path(&db), &src.join("foo.py"));
-
-        // `foo.bar` isn't recognised as a module
-        let foo_bar_module = resolve_module(&db, foo_bar_module_name.clone());
-        assert_eq!(foo_bar_module, None);
-    }
-
    #[test]
    fn typing_stub_over_module() {
        const SRC: &[FileSpec] = &[("foo.py", "print('Hello, world!')"), ("foo.pyi", "x: int")];
--- a/crates/red_knot_python_semantic/src/module_resolver/typeshed/mod.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/typeshed/mod.rs
@@ -0,0 +1,8 @@
+pub use self::vendored::vendored_typeshed_stubs;
+pub(super) use self::versions::{
+    typeshed_versions, vendored_typeshed_versions, TypeshedVersions, TypeshedVersionsParseError,
+    TypeshedVersionsQueryResult,
+};
+
+mod vendored;
+mod versions;
--- a/crates/red_knot_python_semantic/src/module_resolver/typeshed/vendored.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/typeshed/vendored.rs
@@ -6,7 +6,7 @@ use ruff_db::vendored::VendoredFileSystem;
 // Luckily this crate will fail to build if this file isn't available at build time.
 static TYPESHED_ZIP_BYTES: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/zipped_typeshed.zip"));

-pub fn file_system() -> &'static VendoredFileSystem {
+pub fn vendored_typeshed_stubs() -> &'static VendoredFileSystem {
    static VENDORED_TYPESHED_STUBS: Lazy<VendoredFileSystem> =
        Lazy::new(|| VendoredFileSystem::new_static(TYPESHED_ZIP_BYTES).unwrap());
    &VENDORED_TYPESHED_STUBS
@@ -42,7 +42,7 @@ mod tests {
    #[test]
    fn typeshed_vfs_consistent_with_vendored_stubs() {
        let vendored_typeshed_dir = Path::new("vendor/typeshed").canonicalize().unwrap();
-        let vendored_typeshed_stubs = file_system();
+        let vendored_typeshed_stubs = vendored_typeshed_stubs();

        let mut empty_iterator = true;
        for entry in walkdir::WalkDir::new(&vendored_typeshed_dir).min_depth(1) {
--- a/crates/red_knot_python_semantic/src/module_resolver/typeshed/versions.rs
+++ b/crates/red_knot_python_semantic/src/module_resolver/typeshed/versions.rs
@@ -4,19 +4,25 @@ use std::num::{NonZeroU16, NonZeroUsize};
 use std::ops::{RangeFrom, RangeInclusive};
 use std::str::FromStr;

+use once_cell::sync::Lazy;
 use rustc_hash::FxHashMap;

+use super::vendored::vendored_typeshed_stubs;
 use crate::db::Db;
 use crate::module_name::ModuleName;
 use crate::{Program, PythonVersion};

-pub(in crate::module_resolver) fn vendored_typeshed_versions(db: &dyn Db) -> TypeshedVersions {
+static VENDORED_VERSIONS: Lazy<TypeshedVersions> = Lazy::new(|| {
    TypeshedVersions::from_str(
-        &db.vendored()
+        &vendored_typeshed_stubs()
            .read_to_string("stdlib/VERSIONS")
-            .expect("The vendored typeshed stubs should contain a VERSIONS file"),
+            .unwrap(),
    )
-    .expect("The VERSIONS file in the vendored typeshed stubs should be well-formed")
+    .unwrap()
+});
+
+pub(crate) fn vendored_typeshed_versions() -> &'static TypeshedVersions {
+    &VENDORED_VERSIONS
 }

 pub(crate) fn typeshed_versions(db: &dyn Db) -> &TypeshedVersions {
@@ -326,8 +332,6 @@ mod tests {

    use insta::assert_snapshot;

-    use crate::db::tests::TestDb;
-
    use super::*;

    const TYPESHED_STDLIB_DIR: &str = "stdlib";
@@ -349,9 +353,12 @@ mod tests {

    #[test]
    fn can_parse_vendored_versions_file() {
-        let db = TestDb::new();
+        let versions_data = include_str!(concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/vendor/typeshed/stdlib/VERSIONS"
+        ));

-        let versions = vendored_typeshed_versions(&db);
+        let versions = TypeshedVersions::from_str(versions_data).unwrap();
        assert!(versions.len() > 100);
        assert!(versions.len() < 1000);

@@ -388,10 +395,9 @@ mod tests {

    #[test]
    fn typeshed_versions_consistent_with_vendored_stubs() {
-        let db = TestDb::new();
-        let vendored_typeshed_versions = vendored_typeshed_versions(&db);
-        let vendored_typeshed_dir =
-            Path::new(env!("CARGO_MANIFEST_DIR")).join("../red_knot_vendored/vendor/typeshed");
+        const VERSIONS_DATA: &str = include_str!("../../../vendor/typeshed/stdlib/VERSIONS");
+        let vendored_typeshed_dir = Path::new("vendor/typeshed").canonicalize().unwrap();
+        let vendored_typeshed_versions = TypeshedVersions::from_str(VERSIONS_DATA).unwrap();

        let mut empty_iterator = true;

--- a/crates/red_knot_python_semantic/src/python_version.rs
+++ b/crates/red_knot_python_semantic/src/python_version.rs
@@ -54,13 +54,6 @@ impl TryFrom<(&str, &str)> for PythonVersion {
    }
 }

-impl From<(u8, u8)> for PythonVersion {
-    fn from(value: (u8, u8)) -> Self {
-        let (major, minor) = value;
-        Self { major, minor }
-    }
-}
-
 impl fmt::Display for PythonVersion {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let PythonVersion { major, minor } = self;
--- a/crates/red_knot_python_semantic/src/semantic_index.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index.rs
@@ -21,15 +21,12 @@ use crate::Db;

 pub mod ast_ids;
 mod builder;
-pub(crate) mod constraint;
 pub mod definition;
 pub mod expression;
 pub mod symbol;
 mod use_def;

-pub(crate) use self::use_def::{
-    BindingWithConstraints, BindingWithConstraintsIterator, DeclarationsIterator,
-};
+pub(crate) use self::use_def::{DefinitionWithConstraints, DefinitionWithConstraintsIterator};

 type SymbolMap = hashbrown::HashMap<ScopedSymbolId, (), ()>;

@@ -115,9 +112,6 @@ pub(crate) struct SemanticIndex<'db> {
    /// Note: We should not depend on this map when analysing other files or
    /// changing a file invalidates all dependents.
    ast_ids: IndexVec<FileScopeId, AstIds>,
-
-    /// Flags about the global scope (code usage impacting inference)
-    has_future_annotations: bool,
 }

 impl<'db> SemanticIndex<'db> {
@@ -218,12 +212,6 @@ impl<'db> SemanticIndex<'db> {
    pub(crate) fn node_scope(&self, node: NodeWithScopeRef) -> FileScopeId {
        self.scopes_by_node[&node.node_key()]
    }
-
-    /// Checks if there is an import of `__future__.annotations` in the global scope, which affects
-    /// the logic for type inference.
-    pub(super) fn has_future_annotations(&self) -> bool {
-        self.has_future_annotations
-    }
 }

 pub struct AncestorsIter<'a> {
@@ -337,16 +325,16 @@ mod tests {
    use crate::Db;

    impl UseDefMap<'_> {
-        fn first_public_binding(&self, symbol: ScopedSymbolId) -> Option<Definition<'_>> {
-            self.public_bindings(symbol)
+        fn first_public_definition(&self, symbol: ScopedSymbolId) -> Option<Definition<'_>> {
+            self.public_definitions(symbol)
                .next()
-                .map(|constrained_binding| constrained_binding.binding)
+                .map(|constrained_definition| constrained_definition.definition)
        }

-        fn first_binding_at_use(&self, use_id: ScopedUseId) -> Option<Definition<'_>> {
-            self.bindings_at_use(use_id)
+        fn first_use_definition(&self, use_id: ScopedUseId) -> Option<Definition<'_>> {
+            self.use_definitions(use_id)
                .next()
-                .map(|constrained_binding| constrained_binding.binding)
+                .map(|constrained_definition| constrained_definition.definition)
        }
    }

@@ -408,8 +396,8 @@ mod tests {
        let foo = global_table.symbol_id_by_name("foo").unwrap();

        let use_def = use_def_map(&db, scope);
-        let binding = use_def.first_public_binding(foo).unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::Import(_)));
+        let definition = use_def.first_public_definition(foo).unwrap();
+        assert!(matches!(definition.node(&db), DefinitionKind::Import(_)));
    }

    #[test]
@@ -438,19 +426,22 @@ mod tests {
        assert!(
            global_table
                .symbol_by_name("foo")
-                .is_some_and(|symbol| { symbol.is_bound() && !symbol.is_used() }),
+                .is_some_and(|symbol| { symbol.is_defined() && !symbol.is_used() }),
            "symbols that are defined get the defined flag"
        );

        let use_def = use_def_map(&db, scope);
-        let binding = use_def
-            .first_public_binding(
+        let definition = use_def
+            .first_public_definition(
                global_table
                    .symbol_id_by_name("foo")
                    .expect("symbol to exist"),
            )
            .unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::ImportFrom(_)));
+        assert!(matches!(
+            definition.node(&db),
+            DefinitionKind::ImportFrom(_)
+        ));
    }

    #[test]
@@ -463,14 +454,17 @@ mod tests {
        assert!(
            global_table
                .symbol_by_name("foo")
-                .is_some_and(|symbol| { !symbol.is_bound() && symbol.is_used() }),
-            "a symbol used but not bound in a scope should have only the used flag"
+                .is_some_and(|symbol| { !symbol.is_defined() && symbol.is_used() }),
+            "a symbol used but not defined in a scope should have only the used flag"
        );
        let use_def = use_def_map(&db, scope);
-        let binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("x").expect("symbol exists"))
+        let definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("x").expect("symbol exists"))
            .unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::Assignment(_)));
+        assert!(matches!(
+            definition.node(&db),
+            DefinitionKind::Assignment(_)
+        ));
    }

    #[test]
@@ -482,12 +476,12 @@ mod tests {
        assert_eq!(names(&global_table), vec!["x"]);

        let use_def = use_def_map(&db, scope);
-        let binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("x").unwrap())
+        let definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("x").unwrap())
            .unwrap();

        assert!(matches!(
-            binding.kind(&db),
+            definition.node(&db),
            DefinitionKind::AugmentedAssignment(_)
        ));
    }
@@ -520,10 +514,13 @@ y = 2
        assert_eq!(names(&class_table), vec!["x"]);

        let use_def = index.use_def_map(class_scope_id);
-        let binding = use_def
-            .first_public_binding(class_table.symbol_id_by_name("x").expect("symbol exists"))
+        let definition = use_def
+            .first_public_definition(class_table.symbol_id_by_name("x").expect("symbol exists"))
            .unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::Assignment(_)));
+        assert!(matches!(
+            definition.node(&db),
+            DefinitionKind::Assignment(_)
+        ));
    }

    #[test]
@@ -553,14 +550,17 @@ y = 2
        assert_eq!(names(&function_table), vec!["x"]);

        let use_def = index.use_def_map(function_scope_id);
-        let binding = use_def
-            .first_public_binding(
+        let definition = use_def
+            .first_public_definition(
                function_table
                    .symbol_id_by_name("x")
                    .expect("symbol exists"),
            )
            .unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::Assignment(_)));
+        assert!(matches!(
+            definition.node(&db),
+            DefinitionKind::Assignment(_)
+        ));
    }

    #[test]
@@ -592,27 +592,27 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):

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

@@ -640,19 +640,23 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):

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

@@ -690,15 +694,15 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):

        let use_def = index.use_def_map(comprehension_scope_id);
        for name in ["x", "y"] {
-            let binding = use_def
-                .first_public_binding(
+            let definition = use_def
+                .first_public_definition(
                    comprehension_symbol_table
                        .symbol_id_by_name(name)
                        .expect("symbol exists"),
                )
                .unwrap();
            assert!(matches!(
-                binding.kind(&db),
+                definition.node(&db),
                DefinitionKind::Comprehension(_)
            ));
        }
@@ -737,8 +741,8 @@ def f(a: str, /, b: str, c: int = 1, *args, d: int = 2, **kwargs):
        let element_use_id =
            element.scoped_use_id(&db, comprehension_scope_id.to_scope_id(&db, file));

-        let binding = use_def.first_binding_at_use(element_use_id).unwrap();
-        let DefinitionKind::Comprehension(comprehension) = binding.kind(&db) else {
+        let definition = use_def.first_use_definition(element_use_id).unwrap();
+        let DefinitionKind::Comprehension(comprehension) = definition.node(&db) else {
            panic!("expected generator definition")
        };
        let target = comprehension.target();
@@ -817,10 +821,12 @@ with item1 as x, item2 as y:

        let use_def = index.use_def_map(FileScopeId::global());
        for name in ["x", "y"] {
-            let binding = use_def
-                .first_public_binding(global_table.symbol_id_by_name(name).expect("symbol exists"))
-                .expect("Expected with item definition for {name}");
-            assert!(matches!(binding.kind(&db), DefinitionKind::WithItem(_)));
+            let Some(definition) = use_def.first_public_definition(
+                global_table.symbol_id_by_name(name).expect("symbol exists"),
+            ) else {
+                panic!("Expected with item definition for {name}");
+            };
+            assert!(matches!(definition.node(&db), DefinitionKind::WithItem(_)));
        }
    }

@@ -840,10 +846,12 @@ with context() as (x, y):

        let use_def = index.use_def_map(FileScopeId::global());
        for name in ["x", "y"] {
-            let binding = use_def
-                .first_public_binding(global_table.symbol_id_by_name(name).expect("symbol exists"))
-                .expect("Expected with item definition for {name}");
-            assert!(matches!(binding.kind(&db), DefinitionKind::WithItem(_)));
+            let Some(definition) = use_def.first_public_definition(
+                global_table.symbol_id_by_name(name).expect("symbol exists"),
+            ) else {
+                panic!("Expected with item definition for {name}");
+            };
+            assert!(matches!(definition.node(&db), DefinitionKind::WithItem(_)));
        }
    }

@@ -880,14 +888,14 @@ def func():
        assert_eq!(names(&func2_table), vec!["y"]);

        let use_def = index.use_def_map(FileScopeId::global());
-        let binding = use_def
-            .first_public_binding(
+        let definition = use_def
+            .first_public_definition(
                global_table
                    .symbol_id_by_name("func")
                    .expect("symbol exists"),
            )
            .unwrap();
-        assert!(matches!(binding.kind(&db), DefinitionKind::Function(_)));
+        assert!(matches!(definition.node(&db), DefinitionKind::Function(_)));
    }

    #[test]
@@ -955,7 +963,7 @@ class C[T]:
        assert!(
            ann_table
                .symbol_by_name("T")
-                .is_some_and(|s| s.is_bound() && !s.is_used()),
+                .is_some_and(|s| s.is_defined() && !s.is_used()),
            "type parameters are defined by the scope that introduces them"
        );

@@ -987,8 +995,8 @@ class C[T]:
        };
        let x_use_id = x_use_expr_name.scoped_use_id(&db, scope);
        let use_def = use_def_map(&db, scope);
-        let binding = use_def.first_binding_at_use(x_use_id).unwrap();
-        let DefinitionKind::Assignment(assignment) = binding.kind(&db) else {
+        let definition = use_def.first_use_definition(x_use_id).unwrap();
+        let DefinitionKind::Assignment(assignment) = definition.node(&db) else {
            panic!("should be an assignment definition")
        };
        let ast::Expr::NumberLiteral(ast::ExprNumberLiteral {
@@ -1036,7 +1044,7 @@ class C[T]:
        }

        let TestCase { db, file } = test_case(
-            r"
+            r#"
 class Test:
    def foo():
        def bar():
@@ -1045,7 +1053,7 @@ class Test:
        pass

 def x():
-    pass",
+    pass"#,
        );

        let index = semantic_index(&db, file);
@@ -1118,10 +1126,12 @@ match subject:
            ("k", 0),
            ("l", 1),
        ] {
-            let binding = use_def
-                .first_public_binding(global_table.symbol_id_by_name(name).expect("symbol exists"))
+            let definition = use_def
+                .first_public_definition(
+                    global_table.symbol_id_by_name(name).expect("symbol exists"),
+                )
                .expect("Expected with item definition for {name}");
-            if let DefinitionKind::MatchPattern(pattern) = binding.kind(&db) {
+            if let DefinitionKind::MatchPattern(pattern) = definition.node(&db) {
                assert_eq!(pattern.index(), expected_index);
            } else {
                panic!("Expected match pattern definition for {name}");
@@ -1148,10 +1158,12 @@ match 1:

        let use_def = use_def_map(&db, global_scope_id);
        for (name, expected_index) in [("first", 0), ("second", 0)] {
-            let binding = use_def
-                .first_public_binding(global_table.symbol_id_by_name(name).expect("symbol exists"))
+            let definition = use_def
+                .first_public_definition(
+                    global_table.symbol_id_by_name(name).expect("symbol exists"),
+                )
                .expect("Expected with item definition for {name}");
-            if let DefinitionKind::MatchPattern(pattern) = binding.kind(&db) {
+            if let DefinitionKind::MatchPattern(pattern) = definition.node(&db) {
                assert_eq!(pattern.index(), expected_index);
            } else {
                panic!("Expected match pattern definition for {name}");
@@ -1168,11 +1180,11 @@ match 1:
        assert_eq!(&names(&global_table), &["a", "x"]);

        let use_def = use_def_map(&db, scope);
-        let binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("x").unwrap())
+        let definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("x").unwrap())
            .unwrap();

-        assert!(matches!(binding.kind(&db), DefinitionKind::For(_)));
+        assert!(matches!(definition.node(&db), DefinitionKind::For(_)));
    }

    #[test]
@@ -1184,15 +1196,15 @@ match 1:
        assert_eq!(&names(&global_table), &["a", "x", "y"]);

        let use_def = use_def_map(&db, scope);
-        let x_binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("x").unwrap())
+        let x_definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("x").unwrap())
            .unwrap();
-        let y_binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("y").unwrap())
+        let y_definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("y").unwrap())
            .unwrap();

-        assert!(matches!(x_binding.kind(&db), DefinitionKind::For(_)));
-        assert!(matches!(y_binding.kind(&db), DefinitionKind::For(_)));
+        assert!(matches!(x_definition.node(&db), DefinitionKind::For(_)));
+        assert!(matches!(y_definition.node(&db), DefinitionKind::For(_)));
    }

    #[test]
@@ -1204,10 +1216,10 @@ match 1:
        assert_eq!(&names(&global_table), &["e", "a", "b", "c", "d"]);

        let use_def = use_def_map(&db, scope);
-        let binding = use_def
-            .first_public_binding(global_table.symbol_id_by_name("a").unwrap())
+        let definition = use_def
+            .first_public_definition(global_table.symbol_id_by_name("a").unwrap())
            .unwrap();

-        assert!(matches!(binding.kind(&db), DefinitionKind::For(_)));
+        assert!(matches!(definition.node(&db), DefinitionKind::For(_)));
    }
 }
--- a/crates/red_knot_python_semantic/src/semantic_index/builder.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/builder.rs
@@ -19,18 +19,14 @@ use crate::semantic_index::definition::{
 };
 use crate::semantic_index::expression::Expression;
 use crate::semantic_index::symbol::{
-    FileScopeId, NodeWithScopeKey, NodeWithScopeRef, Scope, ScopeId, ScopedSymbolId,
+    FileScopeId, NodeWithScopeKey, NodeWithScopeRef, Scope, ScopeId, ScopedSymbolId, SymbolFlags,
    SymbolTableBuilder,
 };
 use crate::semantic_index::use_def::{FlowSnapshot, UseDefMapBuilder};
 use crate::semantic_index::SemanticIndex;
 use crate::Db;

-use super::constraint::{Constraint, PatternConstraint};
-use super::definition::{
-    DefinitionCategory, ExceptHandlerDefinitionNodeRef, MatchPatternDefinitionNodeRef,
-    WithItemDefinitionNodeRef,
-};
+use super::definition::{MatchPatternDefinitionNodeRef, WithItemDefinitionNodeRef};

 pub(super) struct SemanticIndexBuilder<'db> {
    // Builder state
@@ -45,9 +41,6 @@ pub(super) struct SemanticIndexBuilder<'db> {
    /// Flow states at each `break` in the current loop.
    loop_break_states: Vec<FlowSnapshot>,

-    /// Flags about the file's global scope
-    has_future_annotations: bool,
-
    // Semantic Index fields
    scopes: IndexVec<FileScopeId, Scope>,
    scope_ids_by_scope: IndexVec<FileScopeId, ScopeId<'db>>,
@@ -71,8 +64,6 @@ impl<'db> SemanticIndexBuilder<'db> {
            current_match_case: None,
            loop_break_states: vec![],

-            has_future_annotations: false,
-
            scopes: IndexVec::new(),
            symbol_tables: IndexVec::new(),
            ast_ids: IndexVec::new(),
@@ -174,95 +165,49 @@ impl<'db> SemanticIndexBuilder<'db> {
        self.current_use_def_map_mut().merge(state);
    }

-    fn add_symbol(&mut self, name: Name) -> ScopedSymbolId {
-        let (symbol_id, added) = self.current_symbol_table().add_symbol(name);
+    fn add_or_update_symbol(&mut self, name: Name, flags: SymbolFlags) -> ScopedSymbolId {
+        let symbol_table = self.current_symbol_table();
+        let (symbol_id, added) = symbol_table.add_or_update_symbol(name, flags);
        if added {
-            self.current_use_def_map_mut().add_symbol(symbol_id);
+            let use_def_map = self.current_use_def_map_mut();
+            use_def_map.add_symbol(symbol_id);
        }
        symbol_id
    }

-    fn mark_symbol_bound(&mut self, id: ScopedSymbolId) {
-        self.current_symbol_table().mark_symbol_bound(id);
-    }
-
-    fn mark_symbol_used(&mut self, id: ScopedSymbolId) {
-        self.current_symbol_table().mark_symbol_used(id);
-    }
-
    fn add_definition<'a>(
        &mut self,
        symbol: ScopedSymbolId,
        definition_node: impl Into<DefinitionNodeRef<'a>>,
    ) -> Definition<'db> {
        let definition_node: DefinitionNodeRef<'_> = definition_node.into();
-        #[allow(unsafe_code)]
-        // SAFETY: `definition_node` is guaranteed to be a child of `self.module`
-        let kind = unsafe { definition_node.into_owned(self.module.clone()) };
-        let category = kind.category();
        let definition = Definition::new(
            self.db,
            self.file,
            self.current_scope(),
            symbol,
-            kind,
+            #[allow(unsafe_code)]
+            unsafe {
+                definition_node.into_owned(self.module.clone())
+            },
            countme::Count::default(),
        );

-        let existing_definition = self
-            .definitions_by_node
+        self.definitions_by_node
            .insert(definition_node.key(), definition);
-        debug_assert_eq!(existing_definition, None);
-
-        if category.is_binding() {
-            self.mark_symbol_bound(symbol);
-        }
-
-        let use_def = self.current_use_def_map_mut();
-        match category {
-            DefinitionCategory::DeclarationAndBinding => {
-                use_def.record_declaration_and_binding(symbol, definition);
-            }
-            DefinitionCategory::Declaration => use_def.record_declaration(symbol, definition),
-            DefinitionCategory::Binding => use_def.record_binding(symbol, definition),
-        }
+        self.current_use_def_map_mut()
+            .record_definition(symbol, definition);

        definition
    }

-    fn add_expression_constraint(&mut self, constraint_node: &ast::Expr) -> Expression<'db> {
+    fn add_constraint(&mut self, constraint_node: &ast::Expr) -> Expression<'db> {
        let expression = self.add_standalone_expression(constraint_node);
-        self.current_use_def_map_mut()
-            .record_constraint(Constraint::Expression(expression));
+        self.current_use_def_map_mut().record_constraint(expression);

        expression
    }

-    fn add_pattern_constraint(
-        &mut self,
-        subject: &ast::Expr,
-        pattern: &ast::Pattern,
-    ) -> PatternConstraint<'db> {
-        #[allow(unsafe_code)]
-        let (subject, pattern) = unsafe {
-            (
-                AstNodeRef::new(self.module.clone(), subject),
-                AstNodeRef::new(self.module.clone(), pattern),
-            )
-        };
-        let pattern_constraint = PatternConstraint::new(
-            self.db,
-            self.file,
-            self.current_scope(),
-            subject,
-            pattern,
-            countme::Count::default(),
-        );
-        self.current_use_def_map_mut()
-            .record_constraint(Constraint::Pattern(pattern_constraint));
-        pattern_constraint
-    }
-
    /// Record an expression that needs to be a Salsa ingredient, because we need to infer its type
    /// standalone (type narrowing tests, RHS of an assignment.)
    fn add_standalone_expression(&mut self, expression_node: &ast::Expr) -> Expression<'db> {
@@ -307,13 +252,10 @@ impl<'db> SemanticIndexBuilder<'db> {
                        ..
                    }) => (name, &None, default),
                };
-                let symbol = self.add_symbol(name.id.clone());
-                // TODO create Definition for PEP 695 typevars
-                // note that the "bound" on the typevar is a totally different thing than whether
-                // or not a name is "bound" by a typevar declaration; the latter is always true.
-                self.mark_symbol_bound(symbol);
-                if let Some(bounds) = bound {
-                    self.visit_expr(bounds);
+                // TODO create Definition for typevars
+                self.add_or_update_symbol(name.id.clone(), SymbolFlags::IS_DEFINED);
+                if let Some(bound) = bound {
+                    self.visit_expr(bound);
                }
                if let Some(default) = default {
                    self.visit_expr(default);
@@ -330,23 +272,11 @@ impl<'db> SemanticIndexBuilder<'db> {
        nested_scope
    }

-    /// This method does several things:
-    /// - It pushes a new scope onto the stack for visiting
-    ///   a list/dict/set comprehension or generator expression
-    /// - Inside that scope, it visits a list of [`Comprehension`] nodes,
-    ///   assumed to be the "generators" that compose a comprehension
-    ///   (that is, the `for x in y` and `for y in z` parts of `x for x in y for y in z`).
-    /// - Inside that scope, it also calls a closure for visiting the outer `elt`
-    ///   of a list/dict/set comprehension or generator expression
-    /// - It then pops the new scope off the stack
+    /// Visit a list of [`Comprehension`] nodes, assumed to be the "generators" that compose a
+    /// comprehension (that is, the `for x in y` and `for y in z` parts of `x for x in y for y in z`.)
    ///
    /// [`Comprehension`]: ast::Comprehension
-    fn with_generators_scope(
-        &mut self,
-        scope: NodeWithScopeRef,
-        generators: &'db [ast::Comprehension],
-        visit_outer_elt: impl FnOnce(&mut Self),
-    ) {
+    fn visit_generators(&mut self, scope: NodeWithScopeRef, generators: &'db [ast::Comprehension]) {
        let mut generators_iter = generators.iter();

        let Some(generator) = generators_iter.next() else {
@@ -385,13 +315,11 @@ impl<'db> SemanticIndexBuilder<'db> {
                self.visit_expr(expr);
            }
        }
-
-        visit_outer_elt(self);
-        self.pop_scope();
    }

    fn declare_parameter(&mut self, parameter: AnyParameterRef) {
-        let symbol = self.add_symbol(parameter.name().id().clone());
+        let symbol =
+            self.add_or_update_symbol(parameter.name().id().clone(), SymbolFlags::IS_DEFINED);

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

@@ -399,11 +327,10 @@ impl<'db> SemanticIndexBuilder<'db> {
            // Insert a mapping from the parameter to the same definition.
            // This ensures that calling `HasTy::ty` on the inner parameter returns
            // a valid type (and doesn't panic)
-            let existing_definition = self.definitions_by_node.insert(
+            self.definitions_by_node.insert(
                DefinitionNodeRef::from(AnyParameterRef::Variadic(&with_default.parameter)).key(),
                definition,
            );
-            debug_assert_eq!(existing_definition, None);
        }
    }

@@ -455,7 +382,6 @@ impl<'db> SemanticIndexBuilder<'db> {
            scopes_by_expression: self.scopes_by_expression,
            scopes_by_node: self.scopes_by_node,
            use_def_maps,
-            has_future_annotations: self.has_future_annotations,
        }
    }
 }
@@ -503,7 +429,8 @@ where
                // The symbol for the function name itself has to be evaluated
                // at the end to match the runtime evaluation of parameter defaults
                // and return-type annotations.
-                let symbol = self.add_symbol(function_def.name.id.clone());
+                let symbol = self
+                    .add_or_update_symbol(function_def.name.id.clone(), SymbolFlags::IS_DEFINED);
                self.add_definition(symbol, function_def);
            }
            ast::Stmt::ClassDef(class) => {
@@ -511,7 +438,8 @@ where
                    self.visit_decorator(decorator);
                }

-                let symbol = self.add_symbol(class.name.id.clone());
+                let symbol =
+                    self.add_or_update_symbol(class.name.id.clone(), SymbolFlags::IS_DEFINED);
                self.add_definition(symbol, class);

                self.with_type_params(
@@ -537,7 +465,7 @@ where
                        Name::new(alias.name.id.split('.').next().unwrap())
                    };

-                    let symbol = self.add_symbol(symbol_name);
+                    let symbol = self.add_or_update_symbol(symbol_name, SymbolFlags::IS_DEFINED);
                    self.add_definition(symbol, alias);
                }
            }
@@ -549,16 +477,8 @@ where
                        &alias.name.id
                    };

-                    // Look for imports `from __future__ import annotations`, ignore `as ...`
-                    // We intentionally don't enforce the rules about location of `__future__`
-                    // imports here, we assume the user's intent was to apply the `__future__`
-                    // import, so we still check using it (and will also emit a diagnostic about a
-                    // miss-placed `__future__` import.)
-                    self.has_future_annotations |= alias.name.id == "annotations"
-                        && node.module.as_deref() == Some("__future__");
-
-                    let symbol = self.add_symbol(symbol_name.clone());
-
+                    let symbol =
+                        self.add_or_update_symbol(symbol_name.clone(), SymbolFlags::IS_DEFINED);
                    self.add_definition(symbol, ImportFromDefinitionNodeRef { node, alias_index });
                }
            }
@@ -574,6 +494,7 @@ where
            }
            ast::Stmt::AnnAssign(node) => {
                debug_assert!(self.current_assignment.is_none());
+                // TODO deferred annotation visiting
                self.visit_expr(&node.annotation);
                if let Some(value) = &node.value {
                    self.visit_expr(value);
@@ -599,7 +520,7 @@ where
            ast::Stmt::If(node) => {
                self.visit_expr(&node.test);
                let pre_if = self.flow_snapshot();
-                self.add_expression_constraint(&node.test);
+                self.add_constraint(&node.test);
                self.visit_body(&node.body);
                let mut post_clauses: Vec<FlowSnapshot> = vec![];
                for clause in &node.elif_else_clauses {
@@ -624,23 +545,14 @@ where
                    self.flow_merge(pre_if);
                }
            }
-            ast::Stmt::While(ast::StmtWhile {
-                test,
-                body,
-                orelse,
-                range: _,
-            }) => {
-                self.visit_expr(test);
+            ast::Stmt::While(node) => {
+                self.visit_expr(&node.test);

                let pre_loop = self.flow_snapshot();

                // Save aside any break states from an outer loop
                let saved_break_states = std::mem::take(&mut self.loop_break_states);
-
-                // TODO: definitions created inside the body should be fully visible
-                // to other statements/expressions inside the body --Alex/Carl
-                self.visit_body(body);
-
+                self.visit_body(&node.body);
                // Get the break states from the body of this loop, and restore the saved outer
                // ones.
                let break_states =
@@ -649,7 +561,7 @@ where
                // We may execute the `else` clause without ever executing the body, so merge in
                // the pre-loop state before visiting `else`.
                self.flow_merge(pre_loop);
-                self.visit_body(orelse);
+                self.visit_body(&node.orelse);

                // Breaking out of a while loop bypasses the `else` clause, so merge in the break
                // states after visiting `else`.
@@ -683,35 +595,15 @@ where
                    orelse,
                },
            ) => {
+                // TODO add control flow similar to `ast::Stmt::While` above
                self.add_standalone_expression(iter);
                self.visit_expr(iter);
-
-                let pre_loop = self.flow_snapshot();
-                let saved_break_states = std::mem::take(&mut self.loop_break_states);
-
                debug_assert!(self.current_assignment.is_none());
                self.current_assignment = Some(for_stmt.into());
                self.visit_expr(target);
                self.current_assignment = None;
-
-                // TODO: Definitions created by loop variables
-                // (and definitions created inside the body)
-                // are fully visible to other statements/expressions inside the body --Alex/Carl
                self.visit_body(body);
-
-                let break_states =
-                    std::mem::replace(&mut self.loop_break_states, saved_break_states);
-
-                // We may execute the `else` clause without ever executing the body, so merge in
-                // the pre-loop state before visiting `else`.
-                self.flow_merge(pre_loop);
                self.visit_body(orelse);
-
-                // Breaking out of a `for` loop bypasses the `else` clause, so merge in the break
-                // states after visiting `else`.
-                for break_state in break_states {
-                    self.flow_merge(break_state);
-                }
            }
            ast::Stmt::Match(ast::StmtMatch {
                subject,
@@ -720,74 +612,9 @@ where
            }) => {
                self.add_standalone_expression(subject);
                self.visit_expr(subject);
-
-                let after_subject = self.flow_snapshot();
-                let Some((first, remaining)) = cases.split_first() else {
-                    return;
-                };
-                self.add_pattern_constraint(subject, &first.pattern);
-                self.visit_match_case(first);
-
-                let mut post_case_snapshots = vec![];
-                for case in remaining {
-                    post_case_snapshots.push(self.flow_snapshot());
-                    self.flow_restore(after_subject.clone());
-                    self.add_pattern_constraint(subject, &case.pattern);
+                for case in cases {
                    self.visit_match_case(case);
                }
-                for post_clause_state in post_case_snapshots {
-                    self.flow_merge(post_clause_state);
-                }
-                if !cases
-                    .last()
-                    .is_some_and(|case| case.guard.is_none() && case.pattern.is_wildcard())
-                {
-                    self.flow_merge(after_subject);
-                }
-            }
-            ast::Stmt::Try(ast::StmtTry {
-                body,
-                handlers,
-                orelse,
-                finalbody,
-                is_star,
-                range: _,
-            }) => {
-                self.visit_body(body);
-
-                for except_handler in handlers {
-                    let ast::ExceptHandler::ExceptHandler(except_handler) = except_handler;
-                    let ast::ExceptHandlerExceptHandler {
-                        name: symbol_name,
-                        type_: handled_exceptions,
-                        body: handler_body,
-                        range: _,
-                    } = except_handler;
-
-                    if let Some(handled_exceptions) = handled_exceptions {
-                        self.visit_expr(handled_exceptions);
-                    }
-
-                    // If `handled_exceptions` above was `None`, it's something like `except as e:`,
-                    // which is invalid syntax. However, it's still pretty obvious here that the user
-                    // *wanted* `e` to be bound, so we should still create a definition here nonetheless.
-                    if let Some(symbol_name) = symbol_name {
-                        let symbol = self.add_symbol(symbol_name.id.clone());
-
-                        self.add_definition(
-                            symbol,
-                            DefinitionNodeRef::ExceptHandler(ExceptHandlerDefinitionNodeRef {
-                                handler: except_handler,
-                                is_star: *is_star,
-                            }),
-                        );
-                    }
-
-                    self.visit_body(handler_body);
-                }
-
-                self.visit_body(orelse);
-                self.visit_body(finalbody);
            }
            _ => {
                walk_stmt(self, stmt);
@@ -802,18 +629,23 @@ where

        match expr {
            ast::Expr::Name(name_node @ ast::ExprName { id, ctx, .. }) => {
-                let (is_use, is_definition) = match (ctx, self.current_assignment) {
-                    (ast::ExprContext::Store, Some(CurrentAssignment::AugAssign(_))) => {
-                        // For augmented assignment, the target expression is also used.
-                        (true, true)
-                    }
-                    (ast::ExprContext::Load, _) => (true, false),
-                    (ast::ExprContext::Store, _) => (false, true),
-                    (ast::ExprContext::Del, _) => (false, true),
-                    (ast::ExprContext::Invalid, _) => (false, false),
+                let mut flags = match ctx {
+                    ast::ExprContext::Load => SymbolFlags::IS_USED,
+                    ast::ExprContext::Store => SymbolFlags::IS_DEFINED,
+                    ast::ExprContext::Del => SymbolFlags::IS_DEFINED,
+                    ast::ExprContext::Invalid => SymbolFlags::empty(),
                };
-                let symbol = self.add_symbol(id.clone());
-                if is_definition {
+                if matches!(
+                    self.current_assignment,
+                    Some(CurrentAssignment::AugAssign(_))
+                ) && !ctx.is_invalid()
+                {
+                    // For augmented assignment, the target expression is also used, so we should
+                    // record that as a use.
+                    flags |= SymbolFlags::IS_USED;
+                }
+                let symbol = self.add_or_update_symbol(id.clone(), flags);
+                if flags.contains(SymbolFlags::IS_DEFINED) {
                    match self.current_assignment {
                        Some(CurrentAssignment::Assign(assignment)) => {
                            self.add_definition(
@@ -836,7 +668,6 @@ where
                                ForStmtDefinitionNodeRef {
                                    iterable: &node.iter,
                                    target: name_node,
-                                    is_async: node.is_async,
                                },
                            );
                        }
@@ -853,7 +684,6 @@ where
                                    iterable: &node.iter,
                                    target: name_node,
                                    first,
-                                    is_async: node.is_async,
                                },
                            );
                        }
@@ -870,8 +700,7 @@ where
                    }
                }

-                if is_use {
-                    self.mark_symbol_used(symbol);
+                if flags.contains(SymbolFlags::IS_USED) {
                    let use_id = self.current_ast_ids().record_use(expr);
                    self.current_use_def_map_mut().record_use(symbol, use_id);
                }
@@ -908,7 +737,6 @@ where
                }

                self.visit_expr(lambda.body.as_ref());
-                self.pop_scope();
            }
            ast::Expr::If(ast::ExprIf {
                body, test, orelse, ..
@@ -929,33 +757,30 @@ where
                    elt, generators, ..
                },
            ) => {
-                self.with_generators_scope(
+                self.visit_generators(
                    NodeWithScopeRef::ListComprehension(list_comprehension),
                    generators,
-                    |builder| builder.visit_expr(elt),
                );
+                self.visit_expr(elt);
            }
            ast::Expr::SetComp(
                set_comprehension @ ast::ExprSetComp {
                    elt, generators, ..
                },
            ) => {
-                self.with_generators_scope(
+                self.visit_generators(
                    NodeWithScopeRef::SetComprehension(set_comprehension),
                    generators,
-                    |builder| builder.visit_expr(elt),
                );
+                self.visit_expr(elt);
            }
            ast::Expr::Generator(
                generator @ ast::ExprGenerator {
                    elt, generators, ..
                },
            ) => {
-                self.with_generators_scope(
-                    NodeWithScopeRef::GeneratorExpression(generator),
-                    generators,
-                    |builder| builder.visit_expr(elt),
-                );
+                self.visit_generators(NodeWithScopeRef::GeneratorExpression(generator), generators);
+                self.visit_expr(elt);
            }
            ast::Expr::DictComp(
                dict_comprehension @ ast::ExprDictComp {
@@ -965,19 +790,28 @@ where
                    ..
                },
            ) => {
-                self.with_generators_scope(
+                self.visit_generators(
                    NodeWithScopeRef::DictComprehension(dict_comprehension),
                    generators,
-                    |builder| {
-                        builder.visit_expr(key);
-                        builder.visit_expr(value);
-                    },
                );
+                self.visit_expr(key);
+                self.visit_expr(value);
            }
            _ => {
                walk_expr(self, expr);
            }
        }
+
+        if matches!(
+            expr,
+            ast::Expr::Lambda(_)
+                | ast::Expr::ListComp(_)
+                | ast::Expr::SetComp(_)
+                | ast::Expr::Generator(_)
+                | ast::Expr::DictComp(_)
+        ) {
+            self.pop_scope();
+        }
    }

    fn visit_parameters(&mut self, parameters: &'ast ast::Parameters) {
@@ -1006,7 +840,7 @@ where
            range: _,
        }) = pattern
        {
-            let symbol = self.add_symbol(name.id().clone());
+            let symbol = self.add_or_update_symbol(name.id().clone(), SymbolFlags::IS_DEFINED);
            let state = self.current_match_case.as_ref().unwrap();
            self.add_definition(
                symbol,
@@ -1027,7 +861,7 @@ where
            rest: Some(name), ..
        }) = pattern
        {
-            let symbol = self.add_symbol(name.id().clone());
+            let symbol = self.add_or_update_symbol(name.id().clone(), SymbolFlags::IS_DEFINED);
            let state = self.current_match_case.as_ref().unwrap();
            self.add_definition(
                symbol,
--- a/crates/red_knot_python_semantic/src/semantic_index/constraint.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/constraint.rs
@@ -1,39 +0,0 @@
-use ruff_db::files::File;
-use ruff_python_ast as ast;
-
-use crate::ast_node_ref::AstNodeRef;
-use crate::db::Db;
-use crate::semantic_index::expression::Expression;
-use crate::semantic_index::symbol::{FileScopeId, ScopeId};
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub(crate) enum Constraint<'db> {
-    Expression(Expression<'db>),
-    Pattern(PatternConstraint<'db>),
-}
-
-#[salsa::tracked]
-pub(crate) struct PatternConstraint<'db> {
-    #[id]
-    pub(crate) file: File,
-
-    #[id]
-    pub(crate) file_scope: FileScopeId,
-
-    #[no_eq]
-    #[return_ref]
-    pub(crate) subject: AstNodeRef<ast::Expr>,
-
-    #[no_eq]
-    #[return_ref]
-    pub(crate) pattern: AstNodeRef<ast::Pattern>,
-
-    #[no_eq]
-    count: countme::Count<PatternConstraint<'static>>,
-}
-
-impl<'db> PatternConstraint<'db> {
-    pub(crate) fn scope(self, db: &'db dyn Db) -> ScopeId<'db> {
-        self.file_scope(db).to_scope_id(db, self.file(db))
-    }
-}
--- a/crates/red_knot_python_semantic/src/semantic_index/definition.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/definition.rs
@@ -3,7 +3,6 @@ use ruff_db::parsed::ParsedModule;
 use ruff_python_ast as ast;

 use crate::ast_node_ref::AstNodeRef;
-use crate::module_resolver::file_to_module;
 use crate::node_key::NodeKey;
 use crate::semantic_index::symbol::{FileScopeId, ScopeId, ScopedSymbolId};
 use crate::Db;
@@ -24,7 +23,7 @@ pub struct Definition<'db> {

    #[no_eq]
    #[return_ref]
-    pub(crate) kind: DefinitionKind,
+    pub(crate) node: DefinitionKind,

    #[no_eq]
    count: countme::Count<Definition<'static>>,
@@ -34,26 +33,6 @@ impl<'db> Definition<'db> {
    pub(crate) fn scope(self, db: &'db dyn Db) -> ScopeId<'db> {
        self.file_scope(db).to_scope_id(db, self.file(db))
    }
-
-    pub(crate) fn category(self, db: &'db dyn Db) -> DefinitionCategory {
-        self.kind(db).category()
-    }
-
-    pub(crate) fn is_declaration(self, db: &'db dyn Db) -> bool {
-        self.kind(db).category().is_declaration()
-    }
-
-    pub(crate) fn is_binding(self, db: &'db dyn Db) -> bool {
-        self.kind(db).category().is_binding()
-    }
-
-    /// Return true if this is a symbol was defined in the `typing` or `typing_extensions` modules
-    pub(crate) fn is_typing_definition(self, db: &'db dyn Db) -> bool {
-        file_to_module(db, self.file(db)).is_some_and(|module| {
-            module.search_path().is_standard_library()
-                && matches!(&**module.name(), "typing" | "typing_extensions")
-        })
-    }
 }

 #[derive(Copy, Clone, Debug)]
@@ -71,7 +50,6 @@ pub(crate) enum DefinitionNodeRef<'a> {
    Parameter(ast::AnyParameterRef<'a>),
    WithItem(WithItemDefinitionNodeRef<'a>),
    MatchPattern(MatchPatternDefinitionNodeRef<'a>),
-    ExceptHandler(ExceptHandlerDefinitionNodeRef<'a>),
 }

 impl<'a> From<&'a ast::StmtFunctionDef> for DefinitionNodeRef<'a> {
@@ -174,13 +152,6 @@ pub(crate) struct WithItemDefinitionNodeRef<'a> {
 pub(crate) struct ForStmtDefinitionNodeRef<'a> {
    pub(crate) iterable: &'a ast::Expr,
    pub(crate) target: &'a ast::ExprName,
-    pub(crate) is_async: bool,
-}
-
-#[derive(Copy, Clone, Debug)]
-pub(crate) struct ExceptHandlerDefinitionNodeRef<'a> {
-    pub(crate) handler: &'a ast::ExceptHandlerExceptHandler,
-    pub(crate) is_star: bool,
 }

 #[derive(Copy, Clone, Debug)]
@@ -188,7 +159,6 @@ pub(crate) struct ComprehensionDefinitionNodeRef<'a> {
    pub(crate) iterable: &'a ast::Expr,
    pub(crate) target: &'a ast::ExprName,
    pub(crate) first: bool,
-    pub(crate) is_async: bool,
 }

 #[derive(Copy, Clone, Debug)]
@@ -236,25 +206,20 @@ impl DefinitionNodeRef<'_> {
            DefinitionNodeRef::AugmentedAssignment(augmented_assignment) => {
                DefinitionKind::AugmentedAssignment(AstNodeRef::new(parsed, augmented_assignment))
            }
-            DefinitionNodeRef::For(ForStmtDefinitionNodeRef {
-                iterable,
-                target,
-                is_async,
-            }) => DefinitionKind::For(ForStmtDefinitionKind {
-                iterable: AstNodeRef::new(parsed.clone(), iterable),
-                target: AstNodeRef::new(parsed, target),
-                is_async,
-            }),
+            DefinitionNodeRef::For(ForStmtDefinitionNodeRef { iterable, target }) => {
+                DefinitionKind::For(ForStmtDefinitionKind {
+                    iterable: AstNodeRef::new(parsed.clone(), iterable),
+                    target: AstNodeRef::new(parsed, target),
+                })
+            }
            DefinitionNodeRef::Comprehension(ComprehensionDefinitionNodeRef {
                iterable,
                target,
                first,
-                is_async,
            }) => DefinitionKind::Comprehension(ComprehensionDefinitionKind {
                iterable: AstNodeRef::new(parsed.clone(), iterable),
                target: AstNodeRef::new(parsed, target),
                first,
-                is_async,
            }),
            DefinitionNodeRef::Parameter(parameter) => match parameter {
                ast::AnyParameterRef::Variadic(parameter) => {
@@ -279,13 +244,6 @@ impl DefinitionNodeRef<'_> {
                identifier: AstNodeRef::new(parsed, identifier),
                index,
            }),
-            DefinitionNodeRef::ExceptHandler(ExceptHandlerDefinitionNodeRef {
-                handler,
-                is_star,
-            }) => DefinitionKind::ExceptHandler(ExceptHandlerDefinitionKind {
-                handler: AstNodeRef::new(parsed.clone(), handler),
-                is_star,
-            }),
        }
    }

@@ -307,7 +265,6 @@ impl DefinitionNodeRef<'_> {
            Self::For(ForStmtDefinitionNodeRef {
                iterable: _,
                target,
-                is_async: _,
            }) => target.into(),
            Self::Comprehension(ComprehensionDefinitionNodeRef { target, .. }) => target.into(),
            Self::Parameter(node) => match node {
@@ -318,46 +275,10 @@ impl DefinitionNodeRef<'_> {
            Self::MatchPattern(MatchPatternDefinitionNodeRef { identifier, .. }) => {
                identifier.into()
            }
-            Self::ExceptHandler(ExceptHandlerDefinitionNodeRef { handler, .. }) => handler.into(),
        }
    }
 }

-#[derive(Clone, Copy, Debug)]
-pub(crate) enum DefinitionCategory {
-    /// A Definition which binds a value to a name (e.g. `x = 1`).
-    Binding,
-    /// A Definition which declares the upper-bound of acceptable types for this name (`x: int`).
-    Declaration,
-    /// A Definition which both declares a type and binds a value (e.g. `x: int = 1`).
-    DeclarationAndBinding,
-}
-
-impl DefinitionCategory {
-    /// True if this definition establishes a "declared type" for the symbol.
-    ///
-    /// If so, any assignments reached by this definition are in error if they assign a value of a
-    /// type not assignable to the declared type.
-    ///
-    /// Annotations establish a declared type. So do function and class definitions, and imports.
-    pub(crate) fn is_declaration(self) -> bool {
-        matches!(
-            self,
-            DefinitionCategory::Declaration | DefinitionCategory::DeclarationAndBinding
-        )
-    }
-
-    /// True if this definition assigns a value to the symbol.
-    ///
-    /// False only for annotated assignments without a RHS.
-    pub(crate) fn is_binding(self) -> bool {
-        matches!(
-            self,
-            DefinitionCategory::Binding | DefinitionCategory::DeclarationAndBinding
-        )
-    }
-}
-
 #[derive(Clone, Debug)]
 pub enum DefinitionKind {
    Import(AstNodeRef<ast::Alias>),
@@ -374,52 +295,6 @@ pub enum DefinitionKind {
    ParameterWithDefault(AstNodeRef<ast::ParameterWithDefault>),
    WithItem(WithItemDefinitionKind),
    MatchPattern(MatchPatternDefinitionKind),
-    ExceptHandler(ExceptHandlerDefinitionKind),
-}
-
-impl DefinitionKind {
-    pub(crate) fn category(&self) -> DefinitionCategory {
-        match self {
-            // functions, classes, and imports always bind, and we consider them declarations
-            DefinitionKind::Function(_)
-            | DefinitionKind::Class(_)
-            | DefinitionKind::Import(_)
-            | DefinitionKind::ImportFrom(_) => DefinitionCategory::DeclarationAndBinding,
-            // a parameter always binds a value, but is only a declaration if annotated
-            DefinitionKind::Parameter(parameter) => {
-                if parameter.annotation.is_some() {
-                    DefinitionCategory::DeclarationAndBinding
-                } else {
-                    DefinitionCategory::Binding
-                }
-            }
-            // presence of a default is irrelevant, same logic as for a no-default parameter
-            DefinitionKind::ParameterWithDefault(parameter_with_default) => {
-                if parameter_with_default.parameter.annotation.is_some() {
-                    DefinitionCategory::DeclarationAndBinding
-                } else {
-                    DefinitionCategory::Binding
-                }
-            }
-            // annotated assignment is always a declaration, only a binding if there is a RHS
-            DefinitionKind::AnnotatedAssignment(ann_assign) => {
-                if ann_assign.value.is_some() {
-                    DefinitionCategory::DeclarationAndBinding
-                } else {
-                    DefinitionCategory::Declaration
-                }
-            }
-            // all of these bind values without declaring a type
-            DefinitionKind::NamedExpression(_)
-            | DefinitionKind::Assignment(_)
-            | DefinitionKind::AugmentedAssignment(_)
-            | DefinitionKind::For(_)
-            | DefinitionKind::Comprehension(_)
-            | DefinitionKind::WithItem(_)
-            | DefinitionKind::MatchPattern(_)
-            | DefinitionKind::ExceptHandler(_) => DefinitionCategory::Binding,
-        }
-    }
 }

 #[derive(Clone, Debug)]
@@ -445,7 +320,6 @@ pub struct ComprehensionDefinitionKind {
    iterable: AstNodeRef<ast::Expr>,
    target: AstNodeRef<ast::ExprName>,
    first: bool,
-    is_async: bool,
 }

 impl ComprehensionDefinitionKind {
@@ -460,10 +334,6 @@ impl ComprehensionDefinitionKind {
    pub(crate) fn is_first(&self) -> bool {
        self.first
    }
-
-    pub(crate) fn is_async(&self) -> bool {
-        self.is_async
-    }
 }

 #[derive(Clone, Debug)]
@@ -518,7 +388,6 @@ impl WithItemDefinitionKind {
 pub struct ForStmtDefinitionKind {
    iterable: AstNodeRef<ast::Expr>,
    target: AstNodeRef<ast::ExprName>,
-    is_async: bool,
 }

 impl ForStmtDefinitionKind {
@@ -529,30 +398,6 @@ impl ForStmtDefinitionKind {
    pub(crate) fn target(&self) -> &ast::ExprName {
        self.target.node()
    }
-
-    pub(crate) fn is_async(&self) -> bool {
-        self.is_async
-    }
-}
-
-#[derive(Clone, Debug)]
-pub struct ExceptHandlerDefinitionKind {
-    handler: AstNodeRef<ast::ExceptHandlerExceptHandler>,
-    is_star: bool,
-}
-
-impl ExceptHandlerDefinitionKind {
-    pub(crate) fn node(&self) -> &ast::ExceptHandlerExceptHandler {
-        self.handler.node()
-    }
-
-    pub(crate) fn handled_exceptions(&self) -> Option<&ast::Expr> {
-        self.node().type_.as_deref()
-    }
-
-    pub(crate) fn is_star(&self) -> bool {
-        self.is_star
-    }
 }

 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
@@ -623,9 +468,3 @@ impl From<&ast::Identifier> for DefinitionNodeKey {
        Self(NodeKey::from_node(identifier))
    }
 }
-
-impl From<&ast::ExceptHandlerExceptHandler> for DefinitionNodeKey {
-    fn from(handler: &ast::ExceptHandlerExceptHandler) -> Self {
-        Self(NodeKey::from_node(handler))
-    }
-}
--- a/crates/red_knot_python_semantic/src/semantic_index/symbol.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/symbol.rs
@@ -44,16 +44,16 @@ impl Symbol {
    }

    /// Is the symbol defined in its containing scope?
-    pub fn is_bound(&self) -> bool {
-        self.flags.contains(SymbolFlags::IS_BOUND)
+    pub fn is_defined(&self) -> bool {
+        self.flags.contains(SymbolFlags::IS_DEFINED)
    }
 }

 bitflags! {
    #[derive(Copy, Clone, Debug, Eq, PartialEq)]
-    struct SymbolFlags: u8 {
+    pub(super) struct SymbolFlags: u8 {
        const IS_USED         = 1 << 0;
-        const IS_BOUND      = 1 << 1;
+        const IS_DEFINED      = 1 << 1;
        /// TODO: This flag is not yet set by anything
        const MARKED_GLOBAL   = 1 << 2;
        /// TODO: This flag is not yet set by anything
@@ -272,7 +272,11 @@ impl SymbolTableBuilder {
        }
    }

-    pub(super) fn add_symbol(&mut self, name: Name) -> (ScopedSymbolId, bool) {
+    pub(super) fn add_or_update_symbol(
+        &mut self,
+        name: Name,
+        flags: SymbolFlags,
+    ) -> (ScopedSymbolId, bool) {
        let hash = SymbolTable::hash_name(&name);
        let entry = self
            .table
@@ -281,9 +285,15 @@ impl SymbolTableBuilder {
            .from_hash(hash, |id| self.table.symbols[*id].name() == &name);

        match entry {
-            RawEntryMut::Occupied(entry) => (*entry.key(), false),
+            RawEntryMut::Occupied(entry) => {
+                let symbol = &mut self.table.symbols[*entry.key()];
+                symbol.insert_flags(flags);
+
+                (*entry.key(), false)
+            }
            RawEntryMut::Vacant(entry) => {
-                let symbol = Symbol::new(name);
+                let mut symbol = Symbol::new(name);
+                symbol.insert_flags(flags);

                let id = self.table.symbols.push(symbol);
                entry.insert_with_hasher(hash, id, (), |id| {
@@ -294,14 +304,6 @@ impl SymbolTableBuilder {
        }
    }

-    pub(super) fn mark_symbol_bound(&mut self, id: ScopedSymbolId) {
-        self.table.symbols[id].insert_flags(SymbolFlags::IS_BOUND);
-    }
-
-    pub(super) fn mark_symbol_used(&mut self, id: ScopedSymbolId) {
-        self.table.symbols[id].insert_flags(SymbolFlags::IS_USED);
-    }
-
    pub(super) fn finish(mut self) -> SymbolTable {
        self.table.shrink_to_fit();
        self.table
--- a/crates/red_knot_python_semantic/src/semantic_index/use_def.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/use_def.rs
@@ -1,79 +1,5 @@
-//! First, some terminology:
-//!
-//! * A "binding" gives a new value to a variable. This includes many different Python statements
-//!   (assignment statements of course, but also imports, `def` and `class` statements, `as`
-//!   clauses in `with` and `except` statements, match patterns, and others) and even one
-//!   expression kind (named expressions). It notably does not include annotated assignment
-//!   statements without a right-hand side value; these do not assign any new value to the
-//!   variable. We consider function parameters to be bindings as well, since (from the perspective
-//!   of the function's internal scope), a function parameter begins the scope bound to a value.
-//!
-//! * A "declaration" establishes an upper bound type for the values that a variable may be
-//!   permitted to take on. Annotated assignment statements (with or without an RHS value) are
-//!   declarations; annotated function parameters are also declarations. We consider `def` and
-//!   `class` statements to also be declarations, so as to prohibit accidentally shadowing them.
-//!
-//! Annotated assignments with a right-hand side, and annotated function parameters, are both
-//! bindings and declarations.
-//!
-//! We use [`Definition`] as the universal term (and Salsa tracked struct) encompassing both
-//! bindings and declarations. (This sacrifices a bit of type safety in exchange for improved
-//! performance via fewer Salsa tracked structs and queries, since most declarations -- typed
-//! parameters and annotated assignments with RHS -- are both bindings and declarations.)
-//!
-//! At any given use of a variable, we can ask about both its "declared type" and its "inferred
-//! type". These may be different, but the inferred type must always be assignable to the declared
-//! type; that is, the declared type is always wider, and the inferred type may be more precise. If
-//! we see an invalid assignment, we emit a diagnostic and abandon our inferred type, deferring to
-//! the declared type (this allows an explicit annotation to override bad inference, without a
-//! cast), maintaining the invariant.
-//!
-//! The **inferred type** represents the most precise type we believe encompasses all possible
-//! values for the variable at a given use. It is based on a union of the bindings which can reach
-//! that use through some control flow path, and the narrowing constraints that control flow must
-//! have passed through between the binding and the use. For example, in this code:
-//!
-//! ```python
-//! x = 1 if flag else None
-//! if x is not None:
-//!     use(x)
-//! ```
-//!
-//! For the use of `x` on the third line, the inferred type should be `Literal[1]`. This is based
-//! on the binding on the first line, which assigns the type `Literal[1] | None`, and the narrowing
-//! constraint on the second line, which rules out the type `None`, since control flow must pass
-//! through this constraint to reach the use in question.
-//!
-//! The **declared type** represents the code author's declaration (usually through a type
-//! annotation) that a given variable should not be assigned any type outside the declared type. In
-//! our model, declared types are also control-flow-sensitive; we allow the code author to
-//! explicitly re-declare the same variable with a different type. So for a given binding of a
-//! variable, we will want to ask which declarations of that variable can reach that binding, in
-//! order to determine whether the binding is permitted, or should be a type error. For example:
-//!
-//! ```python
-//! from pathlib import Path
-//! def f(path: str):
-//!     path: Path = Path(path)
-//! ```
-//!
-//! In this function, the initial declared type of `path` is `str`, meaning that the assignment
-//! `path = Path(path)` would be a type error, since it assigns to `path` a value whose type is not
-//! assignable to `str`. This is the purpose of declared types: they prevent accidental assignment
-//! of the wrong type to a variable.
-//!
-//! But in some cases it is useful to "shadow" or "re-declare" a variable with a new type, and we
-//! permit this, as long as it is done with an explicit re-annotation. So `path: Path =
-//! Path(path)`, with the explicit `: Path` annotation, is permitted.
-//!
-//! The general rule is that whatever declaration(s) can reach a given binding determine the
-//! validity of that binding. If there is a path in which the symbol is not declared, that is a
-//! declaration of `Unknown`. If multiple declarations can reach a binding, we union them, but by
-//! default we also issue a type error, since this implicit union of declared types may hide an
-//! error.
-//!
-//! To support type inference, we build a map from each use of a symbol to the bindings live at
-//! that use, and the type narrowing constraints that apply to each binding.
+//! Build a map from each use of a symbol to the definitions visible from that use, and the
+//! type-narrowing constraints that apply to each definition.
 //!
 //! Let's take this code sample:
 //!
@@ -81,157 +7,148 @@
 //! x = 1
 //! x = 2
 //! y = x
-//! if flag:
+//! if y is not None:
 //!     x = 3
 //! else:
 //!     x = 4
 //! z = x
 //! ```
 //!
-//! In this snippet, we have four bindings of `x` (the statements assigning `1`, `2`, `3`, and `4`
-//! to it), and two uses of `x` (the `y = x` and `z = x` assignments). The first binding of `x`
-//! does not reach any use, because it's immediately replaced by the second binding, before any use
-//! happens. (A linter could thus flag the statement `x = 1` as likely superfluous.)
+//! In this snippet, we have four definitions of `x` (the statements assigning `1`, `2`, `3`,
+//! and `4` to it), and two uses of `x` (the `y = x` and `z = x` assignments). The first
+//! [`Definition`] of `x` is never visible to any use, because it's immediately replaced by the
+//! second definition, before any use happens. (A linter could thus flag the statement `x = 1`
+//! as likely superfluous.)
 //!
-//! The first use of `x` has one live binding: the assignment `x = 2`.
+//! The first use of `x` has one definition visible to it: the assignment `x = 2`.
 //!
 //! Things get a bit more complex when we have branches. We will definitely take either the `if` or
-//! the `else` branch. Thus, the second use of `x` has two live bindings: `x = 3` and `x = 4`. The
-//! `x = 2` assignment is no longer visible, because it must be replaced by either `x = 3` or `x =
-//! 4`, no matter which branch was taken. We don't know which branch was taken, so we must consider
-//! both bindings as live, which means eventually we would (in type inference) look at these two
-//! bindings and infer a type of `Literal[3, 4]` -- the union of `Literal[3]` and `Literal[4]` --
-//! for the second use of `x`.
+//! the `else` branch. Thus, the second use of `x` has two definitions visible to it: `x = 3` and
+//! `x = 4`. The `x = 2` definition is no longer visible, because it must be replaced by either `x
+//! = 3` or `x = 4`, no matter which branch was taken. We don't know which branch was taken, so we
+//! must consider both definitions as visible, which means eventually we would (in type inference)
+//! look at these two definitions and infer a type of `Literal[3, 4]` -- the union of `Literal[3]`
+//! and `Literal[4]` -- for the second use of `x`.
 //!
 //! So that's one question our use-def map needs to answer: given a specific use of a symbol, which
-//! binding(s) can reach that use. In [`AstIds`](crate::semantic_index::ast_ids::AstIds) we number
-//! all uses (that means a `Name` node with `Load` context) so we have a `ScopedUseId` to
-//! efficiently represent each use.
+//! definition(s) is/are visible from that use. In
+//! [`AstIds`](crate::semantic_index::ast_ids::AstIds) we number all uses (that means a `Name` node
+//! with `Load` context) so we have a `ScopedUseId` to efficiently represent each use.
 //!
-//! We also need to know, for a given definition of a symbol, what type narrowing constraints apply
+//! Another case we need to handle is when a symbol is referenced from a different scope (the most
+//! obvious example of this is an import). We call this "public" use of a symbol. So the other
+//! question we need to be able to answer is, what are the publicly-visible definitions of each
+//! symbol?
+//!
+//! Technically, public use of a symbol could also occur from any point in control flow of the
+//! scope where the symbol is defined (via inline imports and import cycles, in the case of an
+//! import, or via a function call partway through the local scope that ends up using a symbol from
+//! the scope via a global or nonlocal reference.) But modeling this fully accurately requires
+//! whole-program analysis that isn't tractable for an efficient incremental compiler, since it
+//! means a given symbol could have a different type every place it's referenced throughout the
+//! program, depending on the shape of arbitrarily-sized call/import graphs. So we follow other
+//! Python type-checkers in making the simplifying assumption that usually the scope will finish
+//! execution before its symbols are made visible to other scopes; for instance, most imports will
+//! import from a complete module, not a partially-executed module. (We may want to get a little
+//! smarter than this in the future, in particular for closures, but for now this is where we
+//! start.)
+//!
+//! So this means that the publicly-visible definitions of a symbol are the definitions still
+//! visible at the end of the scope; effectively we have an implicit "use" of every symbol at the
+//! end of the scope.
+//!
+//! We also need to know, for a given definition of a symbol, what type-narrowing constraints apply
 //! to it. For instance, in this code sample:
 //!
 //! ```python
 //! x = 1 if flag else None
 //! if x is not None:
-//!     use(x)
+//!     y = x
 //! ```
 //!
-//! At the use of `x`, the live binding of `x` is `1 if flag else None`, which would infer as the
-//! type `Literal[1] | None`. But the constraint `x is not None` dominates this use, which means we
-//! can rule out the possibility that `x` is `None` here, which should give us the type
-//! `Literal[1]` for this use.
-//!
-//! For declared types, we need to be able to answer the question "given a binding to a symbol,
-//! which declarations of that symbol can reach the binding?" This allows us to emit a diagnostic
-//! if the binding is attempting to bind a value of a type that is not assignable to the declared
-//! type for that symbol, at that point in control flow.
-//!
-//! We also need to know, given a declaration of a symbol, what the inferred type of that symbol is
-//! at that point. This allows us to emit a diagnostic in a case like `x = "foo"; x: int`. The
-//! binding `x = "foo"` occurs before the declaration `x: int`, so according to our
-//! control-flow-sensitive interpretation of declarations, the assignment is not an error. But the
-//! declaration is an error, since it would violate the "inferred type must be assignable to
-//! declared type" rule.
-//!
-//! Another case we need to handle is when a symbol is referenced from a different scope (for
-//! example, an import or a nonlocal reference). We call this "public" use of a symbol. For public
-//! use of a symbol, we prefer the declared type, if there are any declarations of that symbol; if
-//! not, we fall back to the inferred type. So we also need to know which declarations and bindings
-//! can reach the end of the scope.
-//!
-//! Technically, public use of a symbol could occur from any point in control flow of the scope
-//! where the symbol is defined (via inline imports and import cycles, in the case of an import, or
-//! via a function call partway through the local scope that ends up using a symbol from the scope
-//! via a global or nonlocal reference.) But modeling this fully accurately requires whole-program
-//! analysis that isn't tractable for an efficient analysis, since it means a given symbol could
-//! have a different type every place it's referenced throughout the program, depending on the
-//! shape of arbitrarily-sized call/import graphs. So we follow other Python type checkers in
-//! making the simplifying assumption that usually the scope will finish execution before its
-//! symbols are made visible to other scopes; for instance, most imports will import from a
-//! complete module, not a partially-executed module. (We may want to get a little smarter than
-//! this in the future for some closures, but for now this is where we start.)
+//! At the use of `x` in `y = x`, the visible definition of `x` is `1 if flag else None`, which
+//! would infer as the type `Literal[1] | None`. But the constraint `x is not None` dominates this
+//! use, which means we can rule out the possibility that `x` is `None` here, which should give us
+//! the type `Literal[1]` for this use.
 //!
 //! The data structure we build to answer these questions is the `UseDefMap`. It has a
-//! `bindings_by_use` vector of [`SymbolBindings`] indexed by [`ScopedUseId`], a
-//! `declarations_by_binding` vector of [`SymbolDeclarations`] indexed by [`ScopedDefinitionId`], a
-//! `bindings_by_declaration` vector of [`SymbolBindings`] indexed by [`ScopedDefinitionId`], and
-//! `public_bindings` and `public_definitions` vectors indexed by [`ScopedSymbolId`]. The values in
-//! each of these vectors are (in principle) a list of live bindings at that use/definition, or at
-//! the end of the scope for that symbol, with a list of the dominating constraints for each
-//! binding.
+//! `definitions_by_use` vector indexed by [`ScopedUseId`] and a `public_definitions` vector
+//! indexed by [`ScopedSymbolId`]. The values in each of these vectors are (in principle) a list of
+//! visible definitions at that use, or at the end of the scope for that symbol, with a list of the
+//! dominating constraints for each of those definitions.
 //!
 //! In order to avoid vectors-of-vectors-of-vectors and all the allocations that would entail, we
 //! don't actually store these "list of visible definitions" as a vector of [`Definition`].
-//! Instead, [`SymbolBindings`] and [`SymbolDeclarations`] are structs which use bit-sets to track
-//! definitions (and constraints, in the case of bindings) in terms of [`ScopedDefinitionId`] and
-//! [`ScopedConstraintId`], which are indices into the `all_definitions` and `all_constraints`
-//! indexvecs in the [`UseDefMap`].
+//! Instead, the values in `definitions_by_use` and `public_definitions` are a [`SymbolState`]
+//! struct which uses bit-sets to track definitions and constraints in terms of
+//! [`ScopedDefinitionId`] and [`ScopedConstraintId`], which are indices into the `all_definitions`
+//! and `all_constraints` indexvecs in the [`UseDefMap`].
 //!
 //! There is another special kind of possible "definition" for a symbol: there might be a path from
 //! the scope entry to a given use in which the symbol is never bound.
 //!
-//! The simplest way to model "unbound" would be as a "binding" itself: the initial "binding" for
-//! each symbol in a scope. But actually modeling it this way would unnecessarily increase the
-//! number of [`Definition`]s that Salsa must track. Since "unbound" is special in that all symbols
-//! share it, and it doesn't have any additional per-symbol state, and constraints are irrelevant
-//! to it, we can represent it more efficiently: we use the `may_be_unbound` boolean on the
-//! [`SymbolBindings`] struct. If this flag is `true` for a use of a symbol, it means the symbol
-//! has a path to the use in which it is never bound. If this flag is `false`, it means we've
-//! eliminated the possibility of unbound: every control flow path to the use includes a binding
-//! for this symbol.
+//! The simplest way to model "unbound" would be as an actual [`Definition`] itself: the initial
+//! visible [`Definition`] for each symbol in a scope. But actually modeling it this way would
+//! unnecessarily increase the number of [`Definition`] that Salsa must track. Since "unbound" is a
+//! special definition in that all symbols share it, and it doesn't have any additional per-symbol
+//! state, and constraints are irrelevant to it, we can represent it more efficiently: we use the
+//! `may_be_unbound` boolean on the [`SymbolState`] struct. If this flag is `true`, it means the
+//! symbol/use really has one additional visible "definition", which is the unbound state. If this
+//! flag is `false`, it means we've eliminated the possibility of unbound: every path we've
+//! followed includes a definition for this symbol.
 //!
 //! To build a [`UseDefMap`], the [`UseDefMapBuilder`] is notified of each new use, definition, and
 //! constraint as they are encountered by the
 //! [`SemanticIndexBuilder`](crate::semantic_index::builder::SemanticIndexBuilder) AST visit. For
-//! each symbol, the builder tracks the `SymbolState` (`SymbolBindings` and `SymbolDeclarations`)
-//! for that symbol. When we hit a use or definition of a symbol, we record the necessary parts of
-//! the current state for that symbol that we need for that use or definition. When we reach the
-//! end of the scope, it records the state for each symbol as the public definitions of that
-//! symbol.
+//! each symbol, the builder tracks the `SymbolState` for that symbol. When we hit a use of a
+//! symbol, it records the current state for that symbol for that use. When we reach the end of the
+//! scope, it records the state for each symbol as the public definitions of that symbol.
 //!
-//! Let's walk through the above example. Initially we record for `x` that it has no bindings, and
-//! may be unbound. When we see `x = 1`, we record that as the sole live binding of `x`, and flip
-//! `may_be_unbound` to `false`. Then we see `x = 2`, and we replace `x = 1` as the sole live
-//! binding of `x`. When we get to `y = x`, we record that the live bindings for that use of `x`
-//! are just the `x = 2` definition.
+//! Let's walk through the above example. Initially we record for `x` that it has no visible
+//! definitions, and may be unbound. When we see `x = 1`, we record that as the sole visible
+//! definition of `x`, and flip `may_be_unbound` to `false`. Then we see `x = 2`, and it replaces
+//! `x = 1` as the sole visible definition of `x`. When we get to `y = x`, we record that the
+//! visible definitions for that use of `x` are just the `x = 2` definition.
 //!
 //! Then we hit the `if` branch. We visit the `test` node (`flag` in this case), since that will
-//! happen regardless. Then we take a pre-branch snapshot of the current state for all symbols,
-//! which we'll need later. Then we record `flag` as a possible constraint on the current binding
-//! (`x = 2`), and go ahead and visit the `if` body. When we see `x = 3`, it replaces `x = 2`
-//! (constrained by `flag`) as the sole live binding of `x`. At the end of the `if` body, we take
-//! another snapshot of the current symbol state; we'll call this the post-if-body snapshot.
+//! happen regardless. Then we take a pre-branch snapshot of the currently visible definitions for
+//! all symbols, which we'll need later. Then we record `flag` as a possible constraint on the
+//! currently visible definition (`x = 2`), and go ahead and visit the `if` body. When we see `x =
+//! 3`, it replaces `x = 2` (constrained by `flag`) as the sole visible definition of `x`. At the
+//! end of the `if` body, we take another snapshot of the currently-visible definitions; we'll call
+//! this the post-if-body snapshot.
 //!
 //! Now we need to visit the `else` clause. The conditions when entering the `else` clause should
 //! be the pre-if conditions; if we are entering the `else` clause, we know that the `if` test
 //! failed and we didn't execute the `if` body. So we first reset the builder to the pre-if state,
-//! using the snapshot we took previously (meaning we now have `x = 2` as the sole binding for `x`
-//! again), then visit the `else` clause, where `x = 4` replaces `x = 2` as the sole live binding
-//! of `x`.
+//! using the snapshot we took previously (meaning we now have `x = 2` as the sole visible
+//! definition for `x` again), then visit the `else` clause, where `x = 4` replaces `x = 2` as the
+//! sole visible definition of `x`.
 //!
 //! Now we reach the end of the if/else, and want to visit the following code. The state here needs
 //! to reflect that we might have gone through the `if` branch, or we might have gone through the
 //! `else` branch, and we don't know which. So we need to "merge" our current builder state
-//! (reflecting the end-of-else state, with `x = 4` as the only live binding) with our post-if-body
-//! snapshot (which has `x = 3` as the only live binding). The result of this merge is that we now
-//! have two live bindings of `x`: `x = 3` and `x = 4`.
+//! (reflecting the end-of-else state, with `x = 4` as the only visible definition) with our
+//! post-if-body snapshot (which has `x = 3` as the only visible definition). The result of this
+//! merge is that we now have two visible definitions of `x`: `x = 3` and `x = 4`.
 //!
 //! The [`UseDefMapBuilder`] itself just exposes methods for taking a snapshot, resetting to a
 //! snapshot, and merging a snapshot into the current state. The logic using these methods lives in
 //! [`SemanticIndexBuilder`](crate::semantic_index::builder::SemanticIndexBuilder), e.g. where it
 //! visits a `StmtIf` node.
+//!
+//! (In the future we may have some other questions we want to answer as well, such as "is this
+//! definition used?", which will require tracking a bit more info in our map, e.g. a "used" bit
+//! for each [`Definition`] which is flipped to true when we record that definition for a use.)
 use self::symbol_state::{
-    BindingIdWithConstraintsIterator, ConstraintIdIterator, DeclarationIdIterator,
-    ScopedConstraintId, ScopedDefinitionId, SymbolBindings, SymbolDeclarations, SymbolState,
+    ConstraintIdIterator, DefinitionIdWithConstraintsIterator, ScopedConstraintId,
+    ScopedDefinitionId, SymbolState,
 };
 use crate::semantic_index::ast_ids::ScopedUseId;
 use crate::semantic_index::definition::Definition;
+use crate::semantic_index::expression::Expression;
 use crate::semantic_index::symbol::ScopedSymbolId;
 use ruff_index::IndexVec;
-use rustc_hash::FxHashMap;
-
-use super::constraint::Constraint;

 mod bitset;
 mod symbol_state;
@@ -242,135 +159,63 @@ pub(crate) struct UseDefMap<'db> {
    /// Array of [`Definition`] in this scope.
    all_definitions: IndexVec<ScopedDefinitionId, Definition<'db>>,

-    /// Array of [`Constraint`] in this scope.
-    all_constraints: IndexVec<ScopedConstraintId, Constraint<'db>>,
+    /// Array of constraints (as [`Expression`]) in this scope.
+    all_constraints: IndexVec<ScopedConstraintId, Expression<'db>>,

-    /// [`SymbolBindings`] reaching a [`ScopedUseId`].
-    bindings_by_use: IndexVec<ScopedUseId, SymbolBindings>,
-
-    /// [`SymbolBindings`] or [`SymbolDeclarations`] reaching a given [`Definition`].
-    ///
-    /// If the definition is a binding (only) -- `x = 1` for example -- then we need
-    /// [`SymbolDeclarations`] to know whether this binding is permitted by the live declarations.
-    ///
-    /// If the definition is a declaration (only) -- `x: int` for example -- then we need
-    /// [`SymbolBindings`] to know whether this declaration is consistent with the previously
-    /// inferred type.
-    ///
-    /// If the definition is both a declaration and a binding -- `x: int = 1` for example -- then
-    /// we don't actually need anything here, all we'll need to validate is that our own RHS is a
-    /// valid assignment to our own annotation.
-    definitions_by_definition: FxHashMap<Definition<'db>, SymbolDefinitions>,
+    /// [`SymbolState`] visible at a [`ScopedUseId`].
+    definitions_by_use: IndexVec<ScopedUseId, SymbolState>,

    /// [`SymbolState`] visible at end of scope for each symbol.
-    public_symbols: IndexVec<ScopedSymbolId, SymbolState>,
+    public_definitions: IndexVec<ScopedSymbolId, SymbolState>,
 }

 impl<'db> UseDefMap<'db> {
-    pub(crate) fn bindings_at_use(
+    pub(crate) fn use_definitions(
        &self,
        use_id: ScopedUseId,
-    ) -> BindingWithConstraintsIterator<'_, 'db> {
-        self.bindings_iterator(&self.bindings_by_use[use_id])
+    ) -> DefinitionWithConstraintsIterator<'_, 'db> {
+        DefinitionWithConstraintsIterator {
+            all_definitions: &self.all_definitions,
+            all_constraints: &self.all_constraints,
+            inner: self.definitions_by_use[use_id].visible_definitions(),
+        }
    }

    pub(crate) fn use_may_be_unbound(&self, use_id: ScopedUseId) -> bool {
-        self.bindings_by_use[use_id].may_be_unbound()
+        self.definitions_by_use[use_id].may_be_unbound()
    }

-    pub(crate) fn public_bindings(
+    pub(crate) fn public_definitions(
        &self,
        symbol: ScopedSymbolId,
-    ) -> BindingWithConstraintsIterator<'_, 'db> {
-        self.bindings_iterator(self.public_symbols[symbol].bindings())
+    ) -> DefinitionWithConstraintsIterator<'_, 'db> {
+        DefinitionWithConstraintsIterator {
+            all_definitions: &self.all_definitions,
+            all_constraints: &self.all_constraints,
+            inner: self.public_definitions[symbol].visible_definitions(),
+        }
    }

    pub(crate) fn public_may_be_unbound(&self, symbol: ScopedSymbolId) -> bool {
-        self.public_symbols[symbol].may_be_unbound()
+        self.public_definitions[symbol].may_be_unbound()
    }
-
-    pub(crate) fn bindings_at_declaration(
-        &self,
-        declaration: Definition<'db>,
-    ) -> BindingWithConstraintsIterator<'_, 'db> {
-        if let SymbolDefinitions::Bindings(bindings) = &self.definitions_by_definition[&declaration]
-        {
-            self.bindings_iterator(bindings)
-        } else {
-            unreachable!("Declaration has non-Bindings in definitions_by_definition");
-        }
-    }
-
-    pub(crate) fn declarations_at_binding(
-        &self,
-        binding: Definition<'db>,
-    ) -> DeclarationsIterator<'_, 'db> {
-        if let SymbolDefinitions::Declarations(declarations) =
-            &self.definitions_by_definition[&binding]
-        {
-            self.declarations_iterator(declarations)
-        } else {
-            unreachable!("Binding has non-Declarations in definitions_by_definition");
-        }
-    }
-
-    pub(crate) fn public_declarations(
-        &self,
-        symbol: ScopedSymbolId,
-    ) -> DeclarationsIterator<'_, 'db> {
-        let declarations = self.public_symbols[symbol].declarations();
-        self.declarations_iterator(declarations)
-    }
-
-    pub(crate) fn has_public_declarations(&self, symbol: ScopedSymbolId) -> bool {
-        !self.public_symbols[symbol].declarations().is_empty()
-    }
-
-    fn bindings_iterator<'a>(
-        &'a self,
-        bindings: &'a SymbolBindings,
-    ) -> BindingWithConstraintsIterator<'a, 'db> {
-        BindingWithConstraintsIterator {
-            all_definitions: &self.all_definitions,
-            all_constraints: &self.all_constraints,
-            inner: bindings.iter(),
-        }
-    }
-
-    fn declarations_iterator<'a>(
-        &'a self,
-        declarations: &'a SymbolDeclarations,
-    ) -> DeclarationsIterator<'a, 'db> {
-        DeclarationsIterator {
-            all_definitions: &self.all_definitions,
-            inner: declarations.iter(),
-            may_be_undeclared: declarations.may_be_undeclared(),
-        }
-    }
-}
-
-/// Either live bindings or live declarations for a symbol.
-#[derive(Debug, PartialEq, Eq)]
-enum SymbolDefinitions {
-    Bindings(SymbolBindings),
-    Declarations(SymbolDeclarations),
 }

 #[derive(Debug)]
-pub(crate) struct BindingWithConstraintsIterator<'map, 'db> {
+pub(crate) struct DefinitionWithConstraintsIterator<'map, 'db> {
    all_definitions: &'map IndexVec<ScopedDefinitionId, Definition<'db>>,
-    all_constraints: &'map IndexVec<ScopedConstraintId, Constraint<'db>>,
-    inner: BindingIdWithConstraintsIterator<'map>,
+    all_constraints: &'map IndexVec<ScopedConstraintId, Expression<'db>>,
+    inner: DefinitionIdWithConstraintsIterator<'map>,
 }

-impl<'map, 'db> Iterator for BindingWithConstraintsIterator<'map, 'db> {
-    type Item = BindingWithConstraints<'map, 'db>;
+impl<'map, 'db> Iterator for DefinitionWithConstraintsIterator<'map, 'db> {
+    type Item = DefinitionWithConstraints<'map, 'db>;

    fn next(&mut self) -> Option<Self::Item> {
        self.inner
            .next()
-            .map(|def_id_with_constraints| BindingWithConstraints {
-                binding: self.all_definitions[def_id_with_constraints.definition],
+            .map(|def_id_with_constraints| DefinitionWithConstraints {
+                definition: self.all_definitions[def_id_with_constraints.definition],
                constraints: ConstraintsIterator {
                    all_constraints: self.all_constraints,
                    constraint_ids: def_id_with_constraints.constraint_ids,
@@ -379,20 +224,20 @@ impl<'map, 'db> Iterator for BindingWithConstraintsIterator<'map, 'db> {
    }
 }

-impl std::iter::FusedIterator for BindingWithConstraintsIterator<'_, '_> {}
+impl std::iter::FusedIterator for DefinitionWithConstraintsIterator<'_, '_> {}

-pub(crate) struct BindingWithConstraints<'map, 'db> {
-    pub(crate) binding: Definition<'db>,
+pub(crate) struct DefinitionWithConstraints<'map, 'db> {
+    pub(crate) definition: Definition<'db>,
    pub(crate) constraints: ConstraintsIterator<'map, 'db>,
 }

 pub(crate) struct ConstraintsIterator<'map, 'db> {
-    all_constraints: &'map IndexVec<ScopedConstraintId, Constraint<'db>>,
+    all_constraints: &'map IndexVec<ScopedConstraintId, Expression<'db>>,
    constraint_ids: ConstraintIdIterator<'map>,
 }

 impl<'map, 'db> Iterator for ConstraintsIterator<'map, 'db> {
-    type Item = Constraint<'db>;
+    type Item = Expression<'db>;

    fn next(&mut self) -> Option<Self::Item> {
        self.constraint_ids
@@ -403,50 +248,25 @@ impl<'map, 'db> Iterator for ConstraintsIterator<'map, 'db> {

 impl std::iter::FusedIterator for ConstraintsIterator<'_, '_> {}

-pub(crate) struct DeclarationsIterator<'map, 'db> {
-    all_definitions: &'map IndexVec<ScopedDefinitionId, Definition<'db>>,
-    inner: DeclarationIdIterator<'map>,
-    may_be_undeclared: bool,
-}
-
-impl DeclarationsIterator<'_, '_> {
-    pub(crate) fn may_be_undeclared(&self) -> bool {
-        self.may_be_undeclared
-    }
-}
-
-impl<'map, 'db> Iterator for DeclarationsIterator<'map, 'db> {
-    type Item = Definition<'db>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.inner.next().map(|def_id| self.all_definitions[def_id])
-    }
-}
-
-impl std::iter::FusedIterator for DeclarationsIterator<'_, '_> {}
-
 /// A snapshot of the definitions and constraints state at a particular point in control flow.
 #[derive(Clone, Debug)]
 pub(super) struct FlowSnapshot {
-    symbol_states: IndexVec<ScopedSymbolId, SymbolState>,
+    definitions_by_symbol: IndexVec<ScopedSymbolId, SymbolState>,
 }

 #[derive(Debug, Default)]
 pub(super) struct UseDefMapBuilder<'db> {
-    /// Append-only array of [`Definition`].
+    /// Append-only array of [`Definition`]; None is unbound.
    all_definitions: IndexVec<ScopedDefinitionId, Definition<'db>>,

-    /// Append-only array of [`Constraint`].
-    all_constraints: IndexVec<ScopedConstraintId, Constraint<'db>>,
+    /// Append-only array of constraints (as [`Expression`]).
+    all_constraints: IndexVec<ScopedConstraintId, Expression<'db>>,

-    /// Live bindings at each so-far-recorded use.
-    bindings_by_use: IndexVec<ScopedUseId, SymbolBindings>,
+    /// Visible definitions at each so-far-recorded use.
+    definitions_by_use: IndexVec<ScopedUseId, SymbolState>,

-    /// Live bindings or declarations for each so-far-recorded definition.
-    definitions_by_definition: FxHashMap<Definition<'db>, SymbolDefinitions>,
-
-    /// Currently live bindings and declarations for each symbol.
-    symbol_states: IndexVec<ScopedSymbolId, SymbolState>,
+    /// Currently visible definitions for each symbol.
+    definitions_by_symbol: IndexVec<ScopedSymbolId, SymbolState>,
 }

 impl<'db> UseDefMapBuilder<'db> {
@@ -455,104 +275,86 @@ impl<'db> UseDefMapBuilder<'db> {
    }

    pub(super) fn add_symbol(&mut self, symbol: ScopedSymbolId) {
-        let new_symbol = self.symbol_states.push(SymbolState::undefined());
+        let new_symbol = self.definitions_by_symbol.push(SymbolState::unbound());
        debug_assert_eq!(symbol, new_symbol);
    }

-    pub(super) fn record_binding(&mut self, symbol: ScopedSymbolId, binding: Definition<'db>) {
-        let def_id = self.all_definitions.push(binding);
-        let symbol_state = &mut self.symbol_states[symbol];
-        self.definitions_by_definition.insert(
-            binding,
-            SymbolDefinitions::Declarations(symbol_state.declarations().clone()),
-        );
-        symbol_state.record_binding(def_id);
-    }
-
-    pub(super) fn record_constraint(&mut self, constraint: Constraint<'db>) {
-        let constraint_id = self.all_constraints.push(constraint);
-        for state in &mut self.symbol_states {
-            state.record_constraint(constraint_id);
-        }
-    }
-
-    pub(super) fn record_declaration(
-        &mut self,
-        symbol: ScopedSymbolId,
-        declaration: Definition<'db>,
-    ) {
-        let def_id = self.all_definitions.push(declaration);
-        let symbol_state = &mut self.symbol_states[symbol];
-        self.definitions_by_definition.insert(
-            declaration,
-            SymbolDefinitions::Bindings(symbol_state.bindings().clone()),
-        );
-        symbol_state.record_declaration(def_id);
-    }
-
-    pub(super) fn record_declaration_and_binding(
+    pub(super) fn record_definition(
        &mut self,
        symbol: ScopedSymbolId,
        definition: Definition<'db>,
    ) {
-        // We don't need to store anything in self.definitions_by_definition.
+        // We have a new definition of a symbol; this replaces any previous definitions in this
+        // path.
        let def_id = self.all_definitions.push(definition);
-        let symbol_state = &mut self.symbol_states[symbol];
-        symbol_state.record_declaration(def_id);
-        symbol_state.record_binding(def_id);
+        self.definitions_by_symbol[symbol] = SymbolState::with(def_id);
+    }
+
+    pub(super) fn record_constraint(&mut self, constraint: Expression<'db>) {
+        let constraint_id = self.all_constraints.push(constraint);
+        for definitions in &mut self.definitions_by_symbol {
+            definitions.add_constraint(constraint_id);
+        }
    }

    pub(super) fn record_use(&mut self, symbol: ScopedSymbolId, use_id: ScopedUseId) {
-        // We have a use of a symbol; clone the current bindings for that symbol, and record them
-        // as the live bindings for this use.
+        // We have a use of a symbol; clone the currently visible definitions for that symbol, and
+        // record them as the visible definitions for this use.
        let new_use = self
-            .bindings_by_use
-            .push(self.symbol_states[symbol].bindings().clone());
+            .definitions_by_use
+            .push(self.definitions_by_symbol[symbol].clone());
        debug_assert_eq!(use_id, new_use);
    }

    /// Take a snapshot of the current visible-symbols state.
    pub(super) fn snapshot(&self) -> FlowSnapshot {
        FlowSnapshot {
-            symbol_states: self.symbol_states.clone(),
+            definitions_by_symbol: self.definitions_by_symbol.clone(),
        }
    }

-    /// Restore the current builder symbols state to the given snapshot.
+    /// Restore the current builder visible-definitions state to the given snapshot.
    pub(super) fn restore(&mut self, snapshot: FlowSnapshot) {
-        // We never remove symbols from `symbol_states` (it's an IndexVec, and the symbol
+        // We never remove symbols from `definitions_by_symbol` (it's an IndexVec, and the symbol
        // IDs must line up), so the current number of known symbols must always be equal to or
        // greater than the number of known symbols in a previously-taken snapshot.
-        let num_symbols = self.symbol_states.len();
-        debug_assert!(num_symbols >= snapshot.symbol_states.len());
+        let num_symbols = self.definitions_by_symbol.len();
+        debug_assert!(num_symbols >= snapshot.definitions_by_symbol.len());

        // Restore the current visible-definitions state to the given snapshot.
-        self.symbol_states = snapshot.symbol_states;
+        self.definitions_by_symbol = snapshot.definitions_by_symbol;

        // If the snapshot we are restoring is missing some symbols we've recorded since, we need
        // to fill them in so the symbol IDs continue to line up. Since they don't exist in the
-        // snapshot, the correct state to fill them in with is "undefined".
-        self.symbol_states
-            .resize(num_symbols, SymbolState::undefined());
+        // snapshot, the correct state to fill them in with is "unbound".
+        self.definitions_by_symbol
+            .resize(num_symbols, SymbolState::unbound());
    }

    /// Merge the given snapshot into the current state, reflecting that we might have taken either
-    /// path to get here. The new state for each symbol should include definitions from both the
-    /// prior state and the snapshot.
+    /// path to get here. The new visible-definitions state for each symbol should include
+    /// definitions from both the prior state and the snapshot.
    pub(super) fn merge(&mut self, snapshot: FlowSnapshot) {
-        // We never remove symbols from `symbol_states` (it's an IndexVec, and the symbol
+        // The tricky thing about merging two Ranges pointing into `all_definitions` is that if the
+        // two Ranges aren't already adjacent in `all_definitions`, we will have to copy at least
+        // one or the other of the ranges to the end of `all_definitions` so as to make them
+        // adjacent. We can't ever move things around in `all_definitions` because previously
+        // recorded uses may still have ranges pointing to any part of it; all we can do is append.
+        // It's possible we may end up with some old entries in `all_definitions` that nobody is
+        // pointing to, but that's OK.
+
+        // We never remove symbols from `definitions_by_symbol` (it's an IndexVec, and the symbol
        // IDs must line up), so the current number of known symbols must always be equal to or
        // greater than the number of known symbols in a previously-taken snapshot.
-        debug_assert!(self.symbol_states.len() >= snapshot.symbol_states.len());
+        debug_assert!(self.definitions_by_symbol.len() >= snapshot.definitions_by_symbol.len());

-        let mut snapshot_definitions_iter = snapshot.symbol_states.into_iter();
-        for current in &mut self.symbol_states {
+        let mut snapshot_definitions_iter = snapshot.definitions_by_symbol.into_iter();
+        for current in &mut self.definitions_by_symbol {
            if let Some(snapshot) = snapshot_definitions_iter.next() {
                current.merge(snapshot);
            } else {
-                // Symbol not present in snapshot, so it's unbound/undeclared from that path.
-                current.set_may_be_unbound();
-                current.set_may_be_undeclared();
+                // Symbol not present in snapshot, so it's unbound from that path.
+                current.add_unbound();
            }
        }
    }
@@ -560,16 +362,14 @@ impl<'db> UseDefMapBuilder<'db> {
    pub(super) fn finish(mut self) -> UseDefMap<'db> {
        self.all_definitions.shrink_to_fit();
        self.all_constraints.shrink_to_fit();
-        self.symbol_states.shrink_to_fit();
-        self.bindings_by_use.shrink_to_fit();
-        self.definitions_by_definition.shrink_to_fit();
+        self.definitions_by_symbol.shrink_to_fit();
+        self.definitions_by_use.shrink_to_fit();

        UseDefMap {
            all_definitions: self.all_definitions,
            all_constraints: self.all_constraints,
-            bindings_by_use: self.bindings_by_use,
-            public_symbols: self.symbol_states,
-            definitions_by_definition: self.definitions_by_definition,
+            definitions_by_use: self.definitions_by_use,
+            public_definitions: self.definitions_by_symbol,
        }
    }
 }
--- a/crates/red_knot_python_semantic/src/semantic_index/use_def/bitset.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/use_def/bitset.rs
@@ -32,25 +32,17 @@ impl<const B: usize> BitSet<B> {
        bitset
    }

-    pub(super) fn is_empty(&self) -> bool {
-        self.blocks().iter().all(|&b| b == 0)
-    }
-
    /// Convert from Inline to Heap, if needed, and resize the Heap vector, if needed.
    fn resize(&mut self, value: u32) {
        let num_blocks_needed = (value / 64) + 1;
-        self.resize_blocks(num_blocks_needed as usize);
-    }
-
-    fn resize_blocks(&mut self, num_blocks_needed: usize) {
        match self {
            Self::Inline(blocks) => {
                let mut vec = blocks.to_vec();
-                vec.resize(num_blocks_needed, 0);
+                vec.resize(num_blocks_needed as usize, 0);
                *self = Self::Heap(vec);
            }
            Self::Heap(vec) => {
-                vec.resize(num_blocks_needed, 0);
+                vec.resize(num_blocks_needed as usize, 0);
            }
        }
    }
@@ -97,19 +89,6 @@ impl<const B: usize> BitSet<B> {
        }
    }

-    /// Union in-place with another [`BitSet`].
-    pub(super) fn union(&mut self, other: &BitSet<B>) {
-        let mut max_len = self.blocks().len();
-        let other_len = other.blocks().len();
-        if other_len > max_len {
-            max_len = other_len;
-            self.resize_blocks(max_len);
-        }
-        for (my_block, other_block) in self.blocks_mut().iter_mut().zip(other.blocks()) {
-            *my_block |= other_block;
-        }
-    }
-
    /// Return an iterator over the values (in ascending order) in this [`BitSet`].
    pub(super) fn iter(&self) -> BitSetIterator<'_, B> {
        let blocks = self.blocks();
@@ -239,59 +218,6 @@ mod tests {
        assert_bitset(&b1, &[89]);
    }

-    #[test]
-    fn union() {
-        let mut b1 = BitSet::<1>::with(2);
-        let b2 = BitSet::<1>::with(4);
-
-        b1.union(&b2);
-        assert_bitset(&b1, &[2, 4]);
-    }
-
-    #[test]
-    fn union_mixed_1() {
-        let mut b1 = BitSet::<1>::with(4);
-        let mut b2 = BitSet::<1>::with(4);
-        b1.insert(89);
-        b2.insert(5);
-
-        b1.union(&b2);
-        assert_bitset(&b1, &[4, 5, 89]);
-    }
-
-    #[test]
-    fn union_mixed_2() {
-        let mut b1 = BitSet::<1>::with(4);
-        let mut b2 = BitSet::<1>::with(4);
-        b1.insert(23);
-        b2.insert(89);
-
-        b1.union(&b2);
-        assert_bitset(&b1, &[4, 23, 89]);
-    }
-
-    #[test]
-    fn union_heap() {
-        let mut b1 = BitSet::<1>::with(4);
-        let mut b2 = BitSet::<1>::with(4);
-        b1.insert(89);
-        b2.insert(90);
-
-        b1.union(&b2);
-        assert_bitset(&b1, &[4, 89, 90]);
-    }
-
-    #[test]
-    fn union_heap_2() {
-        let mut b1 = BitSet::<1>::with(89);
-        let mut b2 = BitSet::<1>::with(89);
-        b1.insert(91);
-        b2.insert(90);
-
-        b1.union(&b2);
-        assert_bitset(&b1, &[89, 90, 91]);
-    }
-
    #[test]
    fn multiple_blocks() {
        let mut b = BitSet::<2>::with(120);
@@ -299,11 +225,4 @@ mod tests {
        assert!(matches!(b, BitSet::Inline(_)));
        assert_bitset(&b, &[45, 120]);
    }
-
-    #[test]
-    fn empty() {
-        let b = BitSet::<1>::default();
-
-        assert!(b.is_empty());
-    }
 }
--- a/crates/red_knot_python_semantic/src/semantic_index/use_def/symbol_state.rs
+++ b/crates/red_knot_python_semantic/src/semantic_index/use_def/symbol_state.rs
@@ -1,13 +1,13 @@
-//! Track live bindings per symbol, applicable constraints per binding, and live declarations.
+//! Track visible definitions of a symbol, and applicable constraints per definition.
 //!
 //! These data structures operate entirely on scope-local newtype-indices for definitions and
 //! constraints, referring to their location in the `all_definitions` and `all_constraints`
 //! indexvecs in [`super::UseDefMapBuilder`].
 //!
-//! We need to track arbitrary associations between bindings and constraints, not just a single set
-//! of currently dominating constraints (where "dominating" means "control flow must have passed
-//! through it to reach this point"), because we can have dominating constraints that apply to some
-//! bindings but not others, as in this code:
+//! We need to track arbitrary associations between definitions and constraints, not just a single
+//! set of currently dominating constraints (where "dominating" means "control flow must have
+//! passed through it to reach this point"), because we can have dominating constraints that apply
+//! to some definitions but not others, as in this code:
 //!
 //! ```python
 //! x = 1 if flag else None
@@ -18,11 +18,11 @@
 //! ```
 //!
 //! The `x is not None` constraint dominates the final use of `x`, but it applies only to the first
-//! binding of `x`, not the second, so `None` is a possible value for `x`.
+//! definition of `x`, not the second, so `None` is a possible value for `x`.
 //!
-//! And we can't just track, for each binding, an index into a list of dominating constraints,
-//! either, because we can have bindings which are still visible, but subject to constraints that
-//! are no longer dominating, as in this code:
+//! And we can't just track, for each definition, an index into a list of dominating constraints,
+//! either, because we can have definitions which are still visible, but subject to constraints
+//! that are no longer dominating, as in this code:
 //!
 //! ```python
 //! x = 0
@@ -33,16 +33,13 @@
 //! ```
 //!
 //! From the point of view of the final use of `x`, the `x is not None` constraint no longer
-//! dominates, but it does dominate the `x = 1 if flag2 else None` binding, so we have to keep
+//! dominates, but it does dominate the `x = 1 if flag2 else None` definition, so we have to keep
 //! track of that.
 //!
 //! The data structures used here ([`BitSet`] and [`smallvec::SmallVec`]) optimize for keeping all
 //! data inline (avoiding lots of scattered allocations) in small-to-medium cases, and falling back
-//! to heap allocation to be able to scale to arbitrary numbers of live bindings and constraints
-//! when needed.
-//!
-//! Tracking live declarations is simpler, since constraints are not involved, but otherwise very
-//! similar to tracking live bindings.
+//! to heap allocation to be able to scale to arbitrary numbers of definitions and constraints when
+//! needed.
 use super::bitset::{BitSet, BitSetIterator};
 use ruff_index::newtype_index;
 use smallvec::SmallVec;
@@ -56,200 +53,93 @@ pub(super) struct ScopedDefinitionId;
 pub(super) struct ScopedConstraintId;

 /// Can reference this * 64 total definitions inline; more will fall back to the heap.
-const INLINE_BINDING_BLOCKS: usize = 3;
+const INLINE_DEFINITION_BLOCKS: usize = 3;

-/// A [`BitSet`] of [`ScopedDefinitionId`], representing live bindings of a symbol in a scope.
-type Bindings = BitSet<INLINE_BINDING_BLOCKS>;
-type BindingsIterator<'a> = BitSetIterator<'a, INLINE_BINDING_BLOCKS>;
-
-/// Can reference this * 64 total declarations inline; more will fall back to the heap.
-const INLINE_DECLARATION_BLOCKS: usize = 3;
-
-/// A [`BitSet`] of [`ScopedDefinitionId`], representing live declarations of a symbol in a scope.
-type Declarations = BitSet<INLINE_DECLARATION_BLOCKS>;
-type DeclarationsIterator<'a> = BitSetIterator<'a, INLINE_DECLARATION_BLOCKS>;
+/// A [`BitSet`] of [`ScopedDefinitionId`], representing visible definitions of a symbol in a scope.
+type Definitions = BitSet<INLINE_DEFINITION_BLOCKS>;
+type DefinitionsIterator<'a> = BitSetIterator<'a, INLINE_DEFINITION_BLOCKS>;

 /// Can reference this * 64 total constraints inline; more will fall back to the heap.
 const INLINE_CONSTRAINT_BLOCKS: usize = 2;

-/// Can keep inline this many live bindings per symbol at a given time; more will go to heap.
-const INLINE_BINDINGS_PER_SYMBOL: usize = 4;
+/// Can keep inline this many visible definitions per symbol at a given time; more will go to heap.
+const INLINE_VISIBLE_DEFINITIONS_PER_SYMBOL: usize = 4;

-/// One [`BitSet`] of applicable [`ScopedConstraintId`] per live binding.
-type InlineConstraintArray = [BitSet<INLINE_CONSTRAINT_BLOCKS>; INLINE_BINDINGS_PER_SYMBOL];
+/// One [`BitSet`] of applicable [`ScopedConstraintId`] per visible definition.
+type InlineConstraintArray =
+    [BitSet<INLINE_CONSTRAINT_BLOCKS>; INLINE_VISIBLE_DEFINITIONS_PER_SYMBOL];
 type Constraints = SmallVec<InlineConstraintArray>;
 type ConstraintsIterator<'a> = std::slice::Iter<'a, BitSet<INLINE_CONSTRAINT_BLOCKS>>;
 type ConstraintsIntoIterator = smallvec::IntoIter<InlineConstraintArray>;

-/// Live declarations for a single symbol at some point in control flow.
+/// Visible definitions and narrowing constraints for a single symbol at some point in control flow.
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub(super) struct SymbolDeclarations {
-    /// [`BitSet`]: which declarations (as [`ScopedDefinitionId`]) can reach the current location?
-    live_declarations: Declarations,
+pub(super) struct SymbolState {
+    /// [`BitSet`]: which [`ScopedDefinitionId`] are visible for this symbol?
+    visible_definitions: Definitions,

-    /// Could the symbol be un-declared at this point?
-    may_be_undeclared: bool,
-}
-
-impl SymbolDeclarations {
-    fn undeclared() -> Self {
-        Self {
-            live_declarations: Declarations::default(),
-            may_be_undeclared: true,
-        }
-    }
-
-    /// Record a newly-encountered declaration for this symbol.
-    fn record_declaration(&mut self, declaration_id: ScopedDefinitionId) {
-        self.live_declarations = Declarations::with(declaration_id.into());
-        self.may_be_undeclared = false;
-    }
-
-    /// Add undeclared as a possibility for this symbol.
-    fn set_may_be_undeclared(&mut self) {
-        self.may_be_undeclared = true;
-    }
-
-    /// Return an iterator over live declarations for this symbol.
-    pub(super) fn iter(&self) -> DeclarationIdIterator {
-        DeclarationIdIterator {
-            inner: self.live_declarations.iter(),
-        }
-    }
-
-    pub(super) fn is_empty(&self) -> bool {
-        self.live_declarations.is_empty()
-    }
-
-    pub(super) fn may_be_undeclared(&self) -> bool {
-        self.may_be_undeclared
-    }
-}
-
-/// Live bindings and narrowing constraints for a single symbol at some point in control flow.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(super) struct SymbolBindings {
-    /// [`BitSet`]: which bindings (as [`ScopedDefinitionId`]) can reach the current location?
-    live_bindings: Bindings,
-
-    /// For each live binding, which [`ScopedConstraintId`] apply?
+    /// For each definition, which [`ScopedConstraintId`] apply?
    ///
    /// This is a [`smallvec::SmallVec`] which should always have one [`BitSet`] of constraints per
-    /// binding in `live_bindings`.
+    /// definition in `visible_definitions`.
    constraints: Constraints,

    /// Could the symbol be unbound at this point?
    may_be_unbound: bool,
 }

-impl SymbolBindings {
-    fn unbound() -> Self {
+/// A single [`ScopedDefinitionId`] with an iterator of its applicable [`ScopedConstraintId`].
+#[derive(Debug)]
+pub(super) struct DefinitionIdWithConstraints<'a> {
+    pub(super) definition: ScopedDefinitionId,
+    pub(super) constraint_ids: ConstraintIdIterator<'a>,
+}
+
+impl SymbolState {
+    /// Return a new [`SymbolState`] representing an unbound symbol.
+    pub(super) fn unbound() -> Self {
        Self {
-            live_bindings: Bindings::default(),
+            visible_definitions: Definitions::default(),
            constraints: Constraints::default(),
            may_be_unbound: true,
        }
    }

+    /// Return a new [`SymbolState`] representing a symbol with a single visible definition.
+    pub(super) fn with(definition_id: ScopedDefinitionId) -> Self {
+        let mut constraints = Constraints::with_capacity(1);
+        constraints.push(BitSet::default());
+        Self {
+            visible_definitions: Definitions::with(definition_id.into()),
+            constraints,
+            may_be_unbound: false,
+        }
+    }
+
    /// Add Unbound as a possibility for this symbol.
-    fn set_may_be_unbound(&mut self) {
+    pub(super) fn add_unbound(&mut self) {
        self.may_be_unbound = true;
    }

-    /// Record a newly-encountered binding for this symbol.
-    pub(super) fn record_binding(&mut self, binding_id: ScopedDefinitionId) {
-        // The new binding replaces all previous live bindings in this path, and has no
-        // constraints.
-        self.live_bindings = Bindings::with(binding_id.into());
-        self.constraints = Constraints::with_capacity(1);
-        self.constraints.push(BitSet::default());
-        self.may_be_unbound = false;
-    }
-
-    /// Add given constraint to all live bindings.
-    pub(super) fn record_constraint(&mut self, constraint_id: ScopedConstraintId) {
+    /// Add given constraint to all currently-visible definitions.
+    pub(super) fn add_constraint(&mut self, constraint_id: ScopedConstraintId) {
        for bitset in &mut self.constraints {
            bitset.insert(constraint_id.into());
        }
    }

-    /// Iterate over currently live bindings for this symbol.
-    pub(super) fn iter(&self) -> BindingIdWithConstraintsIterator {
-        BindingIdWithConstraintsIterator {
-            definitions: self.live_bindings.iter(),
-            constraints: self.constraints.iter(),
-        }
-    }
-
-    pub(super) fn may_be_unbound(&self) -> bool {
-        self.may_be_unbound
-    }
-}
-
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(super) struct SymbolState {
-    declarations: SymbolDeclarations,
-    bindings: SymbolBindings,
-}
-
-impl SymbolState {
-    /// Return a new [`SymbolState`] representing an unbound, undeclared symbol.
-    pub(super) fn undefined() -> Self {
-        Self {
-            declarations: SymbolDeclarations::undeclared(),
-            bindings: SymbolBindings::unbound(),
-        }
-    }
-
-    /// Add Unbound as a possibility for this symbol.
-    pub(super) fn set_may_be_unbound(&mut self) {
-        self.bindings.set_may_be_unbound();
-    }
-
-    /// Record a newly-encountered binding for this symbol.
-    pub(super) fn record_binding(&mut self, binding_id: ScopedDefinitionId) {
-        self.bindings.record_binding(binding_id);
-    }
-
-    /// Add given constraint to all live bindings.
-    pub(super) fn record_constraint(&mut self, constraint_id: ScopedConstraintId) {
-        self.bindings.record_constraint(constraint_id);
-    }
-
-    /// Add undeclared as a possibility for this symbol.
-    pub(super) fn set_may_be_undeclared(&mut self) {
-        self.declarations.set_may_be_undeclared();
-    }
-
-    /// Record a newly-encountered declaration of this symbol.
-    pub(super) fn record_declaration(&mut self, declaration_id: ScopedDefinitionId) {
-        self.declarations.record_declaration(declaration_id);
-    }
-
    /// Merge another [`SymbolState`] into this one.
    pub(super) fn merge(&mut self, b: SymbolState) {
        let mut a = Self {
-            bindings: SymbolBindings {
-                live_bindings: Bindings::default(),
-                constraints: Constraints::default(),
-                may_be_unbound: self.bindings.may_be_unbound || b.bindings.may_be_unbound,
-            },
-            declarations: SymbolDeclarations {
-                live_declarations: self.declarations.live_declarations.clone(),
-                may_be_undeclared: self.declarations.may_be_undeclared
-                    || b.declarations.may_be_undeclared,
-            },
+            visible_definitions: Definitions::default(),
+            constraints: Constraints::default(),
+            may_be_unbound: self.may_be_unbound || b.may_be_unbound,
        };
-
        std::mem::swap(&mut a, self);
-        self.declarations
-            .live_declarations
-            .union(&b.declarations.live_declarations);
-
-        let mut a_defs_iter = a.bindings.live_bindings.iter();
-        let mut b_defs_iter = b.bindings.live_bindings.iter();
-        let mut a_constraints_iter = a.bindings.constraints.into_iter();
-        let mut b_constraints_iter = b.bindings.constraints.into_iter();
+        let mut a_defs_iter = a.visible_definitions.iter();
+        let mut b_defs_iter = b.visible_definitions.iter();
+        let mut a_constraints_iter = a.constraints.into_iter();
+        let mut b_constraints_iter = b.constraints.into_iter();

        let mut opt_a_def: Option<u32> = a_defs_iter.next();
        let mut opt_b_def: Option<u32> = b_defs_iter.next();
@@ -262,7 +152,7 @@ impl SymbolState {

        // Helper to push `def`, with constraints in `constraints_iter`, onto `self`.
        let push = |def, constraints_iter: &mut ConstraintsIntoIterator, merged: &mut Self| {
-            merged.bindings.live_bindings.insert(def);
+            merged.visible_definitions.insert(def);
            // SAFETY: we only ever create SymbolState with either no definitions and no constraint
            // bitsets (`::unbound`) or one definition and one constraint bitset (`::with`), and
            // `::merge` always pushes one definition and one constraint bitset together (just
@@ -271,7 +161,7 @@ impl SymbolState {
            let constraints = constraints_iter
                .next()
                .expect("definitions and constraints length mismatch");
-            merged.bindings.constraints.push(constraints);
+            merged.constraints.push(constraints);
        };

        loop {
@@ -301,8 +191,7 @@ impl SymbolState {
                        // If the same definition is visible through both paths, any constraint
                        // that applies on only one path is irrelevant to the resulting type from
                        // unioning the two paths, so we intersect the constraints.
-                        self.bindings
-                            .constraints
+                        self.constraints
                            .last_mut()
                            .unwrap()
                            .intersect(&a_constraints);
@@ -325,49 +214,40 @@ impl SymbolState {
        }
    }

-    pub(super) fn bindings(&self) -> &SymbolBindings {
-        &self.bindings
-    }
-
-    pub(super) fn declarations(&self) -> &SymbolDeclarations {
-        &self.declarations
+    /// Get iterator over visible definitions with constraints.
+    pub(super) fn visible_definitions(&self) -> DefinitionIdWithConstraintsIterator {
+        DefinitionIdWithConstraintsIterator {
+            definitions: self.visible_definitions.iter(),
+            constraints: self.constraints.iter(),
+        }
    }

    /// Could the symbol be unbound?
    pub(super) fn may_be_unbound(&self) -> bool {
-        self.bindings.may_be_unbound()
+        self.may_be_unbound
    }
 }

-/// The default state of a symbol, if we've seen no definitions of it, is undefined (that is,
-/// both unbound and undeclared).
+/// The default state of a symbol (if we've seen no definitions of it) is unbound.
 impl Default for SymbolState {
    fn default() -> Self {
-        SymbolState::undefined()
+        SymbolState::unbound()
    }
 }

-/// A single binding (as [`ScopedDefinitionId`]) with an iterator of its applicable
-/// [`ScopedConstraintId`].
 #[derive(Debug)]
-pub(super) struct BindingIdWithConstraints<'a> {
-    pub(super) definition: ScopedDefinitionId,
-    pub(super) constraint_ids: ConstraintIdIterator<'a>,
-}
-
-#[derive(Debug)]
-pub(super) struct BindingIdWithConstraintsIterator<'a> {
-    definitions: BindingsIterator<'a>,
+pub(super) struct DefinitionIdWithConstraintsIterator<'a> {
+    definitions: DefinitionsIterator<'a>,
    constraints: ConstraintsIterator<'a>,
 }

-impl<'a> Iterator for BindingIdWithConstraintsIterator<'a> {
-    type Item = BindingIdWithConstraints<'a>;
+impl<'a> Iterator for DefinitionIdWithConstraintsIterator<'a> {
+    type Item = DefinitionIdWithConstraints<'a>;

    fn next(&mut self) -> Option<Self::Item> {
        match (self.definitions.next(), self.constraints.next()) {
            (None, None) => None,
-            (Some(def), Some(constraints)) => Some(BindingIdWithConstraints {
+            (Some(def), Some(constraints)) => Some(DefinitionIdWithConstraints {
                definition: ScopedDefinitionId::from_u32(def),
                constraint_ids: ConstraintIdIterator {
                    wrapped: constraints.iter(),
@@ -379,7 +259,7 @@ impl<'a> Iterator for BindingIdWithConstraintsIterator<'a> {
    }
 }

-impl std::iter::FusedIterator for BindingIdWithConstraintsIterator<'_> {}
+impl std::iter::FusedIterator for DefinitionIdWithConstraintsIterator<'_> {}

 #[derive(Debug)]
 pub(super) struct ConstraintIdIterator<'a> {
@@ -396,193 +276,99 @@ impl Iterator for ConstraintIdIterator<'_> {

 impl std::iter::FusedIterator for ConstraintIdIterator<'_> {}

-#[derive(Debug)]
-pub(super) struct DeclarationIdIterator<'a> {
-    inner: DeclarationsIterator<'a>,
-}
-
-impl<'a> Iterator for DeclarationIdIterator<'a> {
-    type Item = ScopedDefinitionId;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        self.inner.next().map(ScopedDefinitionId::from_u32)
-    }
-}
-
-impl std::iter::FusedIterator for DeclarationIdIterator<'_> {}
-
 #[cfg(test)]
 mod tests {
    use super::{ScopedConstraintId, ScopedDefinitionId, SymbolState};

-    fn assert_bindings(symbol: &SymbolState, may_be_unbound: bool, expected: &[&str]) {
-        assert_eq!(symbol.may_be_unbound(), may_be_unbound);
-        let actual = symbol
-            .bindings()
-            .iter()
-            .map(|def_id_with_constraints| {
-                format!(
-                    "{}<{}>",
-                    def_id_with_constraints.definition.as_u32(),
-                    def_id_with_constraints
-                        .constraint_ids
-                        .map(ScopedConstraintId::as_u32)
-                        .map(|idx| idx.to_string())
-                        .collect::<Vec<_>>()
-                        .join(", ")
-                )
-            })
-            .collect::<Vec<_>>();
-        assert_eq!(actual, expected);
-    }
-
-    pub(crate) fn assert_declarations(
-        symbol: &SymbolState,
-        may_be_undeclared: bool,
-        expected: &[u32],
-    ) {
-        assert_eq!(symbol.declarations.may_be_undeclared(), may_be_undeclared);
-        let actual = symbol
-            .declarations()
-            .iter()
-            .map(ScopedDefinitionId::as_u32)
-            .collect::<Vec<_>>();
-        assert_eq!(actual, expected);
+    impl SymbolState {
+        pub(crate) fn assert(&self, may_be_unbound: bool, expected: &[&str]) {
+            assert_eq!(self.may_be_unbound(), may_be_unbound);
+            let actual = self
+                .visible_definitions()
+                .map(|def_id_with_constraints| {
+                    format!(
+                        "{}<{}>",
+                        def_id_with_constraints.definition.as_u32(),
+                        def_id_with_constraints
+                            .constraint_ids
+                            .map(ScopedConstraintId::as_u32)
+                            .map(|idx| idx.to_string())
+                            .collect::<Vec<_>>()
+                            .join(", ")
+                    )
+                })
+                .collect::<Vec<_>>();
+            assert_eq!(actual, expected);
+        }
    }

    #[test]
    fn unbound() {
-        let sym = SymbolState::undefined();
+        let cd = SymbolState::unbound();

-        assert_bindings(&sym, true, &[]);
+        cd.assert(true, &[]);
    }

    #[test]
    fn with() {
-        let mut sym = SymbolState::undefined();
-        sym.record_binding(ScopedDefinitionId::from_u32(0));
+        let cd = SymbolState::with(ScopedDefinitionId::from_u32(0));

-        assert_bindings(&sym, false, &["0<>"]);
+        cd.assert(false, &["0<>"]);
    }

    #[test]
-    fn set_may_be_unbound() {
-        let mut sym = SymbolState::undefined();
-        sym.record_binding(ScopedDefinitionId::from_u32(0));
-        sym.set_may_be_unbound();
+    fn add_unbound() {
+        let mut cd = SymbolState::with(ScopedDefinitionId::from_u32(0));
+        cd.add_unbound();

-        assert_bindings(&sym, true, &["0<>"]);
+        cd.assert(true, &["0<>"]);
    }

    #[test]
-    fn record_constraint() {
-        let mut sym = SymbolState::undefined();
-        sym.record_binding(ScopedDefinitionId::from_u32(0));
-        sym.record_constraint(ScopedConstraintId::from_u32(0));
+    fn add_constraint() {
+        let mut cd = SymbolState::with(ScopedDefinitionId::from_u32(0));
+        cd.add_constraint(ScopedConstraintId::from_u32(0));

-        assert_bindings(&sym, false, &["0<0>"]);
+        cd.assert(false, &["0<0>"]);
    }

    #[test]
    fn merge() {
        // merging the same definition with the same constraint keeps the constraint
-        let mut sym0a = SymbolState::undefined();
-        sym0a.record_binding(ScopedDefinitionId::from_u32(0));
-        sym0a.record_constraint(ScopedConstraintId::from_u32(0));
+        let mut cd0a = SymbolState::with(ScopedDefinitionId::from_u32(0));
+        cd0a.add_constraint(ScopedConstraintId::from_u32(0));

-        let mut sym0b = SymbolState::undefined();
-        sym0b.record_binding(ScopedDefinitionId::from_u32(0));
-        sym0b.record_constraint(ScopedConstraintId::from_u32(0));
+        let mut cd0b = SymbolState::with(ScopedDefinitionId::from_u32(0));
+        cd0b.add_constraint(ScopedConstraintId::from_u32(0));

-        sym0a.merge(sym0b);
-        let mut sym0 = sym0a;
-        assert_bindings(&sym0, false, &["0<0>"]);
+        cd0a.merge(cd0b);
+        let mut cd0 = cd0a;
+        cd0.assert(false, &["0<0>"]);

        // merging the same definition with differing constraints drops all constraints
-        let mut sym1a = SymbolState::undefined();
-        sym1a.record_binding(ScopedDefinitionId::from_u32(1));
-        sym1a.record_constraint(ScopedConstraintId::from_u32(1));
+        let mut cd1a = SymbolState::with(ScopedDefinitionId::from_u32(1));
+        cd1a.add_constraint(ScopedConstraintId::from_u32(1));

-        let mut sym1b = SymbolState::undefined();
-        sym1b.record_binding(ScopedDefinitionId::from_u32(1));
-        sym1b.record_constraint(ScopedConstraintId::from_u32(2));
+        let mut cd1b = SymbolState::with(ScopedDefinitionId::from_u32(1));
+        cd1b.add_constraint(ScopedConstraintId::from_u32(2));

-        sym1a.merge(sym1b);
-        let sym1 = sym1a;
-        assert_bindings(&sym1, false, &["1<>"]);
+        cd1a.merge(cd1b);
+        let cd1 = cd1a;
+        cd1.assert(false, &["1<>"]);

        // merging a constrained definition with unbound keeps both
-        let mut sym2a = SymbolState::undefined();
-        sym2a.record_binding(ScopedDefinitionId::from_u32(2));
-        sym2a.record_constraint(ScopedConstraintId::from_u32(3));
+        let mut cd2a = SymbolState::with(ScopedDefinitionId::from_u32(2));
+        cd2a.add_constraint(ScopedConstraintId::from_u32(3));

-        let sym2b = SymbolState::undefined();
+        let cd2b = SymbolState::unbound();

-        sym2a.merge(sym2b);
-        let sym2 = sym2a;
-        assert_bindings(&sym2, true, &["2<3>"]);
+        cd2a.merge(cd2b);
+        let cd2 = cd2a;
+        cd2.assert(true, &["2<3>"]);

        // merging different definitions keeps them each with their existing constraints
-        sym0.merge(sym2);
-        let sym = sym0;
-        assert_bindings(&sym, true, &["0<0>", "2<3>"]);
-    }
-
-    #[test]
-    fn no_declaration() {
-        let sym = SymbolState::undefined();
-
-        assert_declarations(&sym, true, &[]);
-    }
-
-    #[test]
-    fn record_declaration() {
-        let mut sym = SymbolState::undefined();
-        sym.record_declaration(ScopedDefinitionId::from_u32(1));
-
-        assert_declarations(&sym, false, &[1]);
-    }
-
-    #[test]
-    fn record_declaration_override() {
-        let mut sym = SymbolState::undefined();
-        sym.record_declaration(ScopedDefinitionId::from_u32(1));
-        sym.record_declaration(ScopedDefinitionId::from_u32(2));
-
-        assert_declarations(&sym, false, &[2]);
-    }
-
-    #[test]
-    fn record_declaration_merge() {
-        let mut sym = SymbolState::undefined();
-        sym.record_declaration(ScopedDefinitionId::from_u32(1));
-
-        let mut sym2 = SymbolState::undefined();
-        sym2.record_declaration(ScopedDefinitionId::from_u32(2));
-
-        sym.merge(sym2);
-
-        assert_declarations(&sym, false, &[1, 2]);
-    }
-
-    #[test]
-    fn record_declaration_merge_partial_undeclared() {
-        let mut sym = SymbolState::undefined();
-        sym.record_declaration(ScopedDefinitionId::from_u32(1));
-
-        let sym2 = SymbolState::undefined();
-
-        sym.merge(sym2);
-
-        assert_declarations(&sym, true, &[1]);
-    }
-
-    #[test]
-    fn set_may_be_undeclared() {
-        let mut sym = SymbolState::undefined();
-        sym.record_declaration(ScopedDefinitionId::from_u32(0));
-        sym.set_may_be_undeclared();
-
-        assert_declarations(&sym, true, &[0]);
+        cd0.merge(cd2);
+        let cd = cd0;
+        cd.assert(true, &["0<0>", "2<3>"]);
    }
 }
--- a/crates/red_knot_python_semantic/src/semantic_model.rs
+++ b/crates/red_knot_python_semantic/src/semantic_model.rs
@@ -8,7 +8,7 @@ use crate::module_name::ModuleName;
 use crate::module_resolver::{resolve_module, Module};
 use crate::semantic_index::ast_ids::HasScopedAstId;
 use crate::semantic_index::semantic_index;
-use crate::types::{binding_ty, global_symbol_ty, infer_scope_types, Type};
+use crate::types::{definition_ty, global_symbol_ty_by_name, infer_scope_types, Type};
 use crate::Db;

 pub struct SemanticModel<'db> {
@@ -40,7 +40,7 @@ impl<'db> SemanticModel<'db> {
    }

    pub fn global_symbol_ty(&self, module: &Module, symbol_name: &str) -> Type<'db> {
-        global_symbol_ty(self.db, module.file(), symbol_name)
+        global_symbol_ty_by_name(self.db, module.file(), symbol_name)
    }
 }

@@ -147,24 +147,24 @@ impl HasTy for ast::Expr {
    }
 }

-macro_rules! impl_binding_has_ty {
+macro_rules! impl_definition_has_ty {
    ($ty: ty) => {
        impl HasTy for $ty {
            #[inline]
            fn ty<'db>(&self, model: &SemanticModel<'db>) -> Type<'db> {
                let index = semantic_index(model.db, model.file);
-                let binding = index.definition(self);
-                binding_ty(model.db, binding)
+                let definition = index.definition(self);
+                definition_ty(model.db, definition)
            }
        }
    };
 }

-impl_binding_has_ty!(ast::StmtFunctionDef);
-impl_binding_has_ty!(ast::StmtClassDef);
-impl_binding_has_ty!(ast::Alias);
-impl_binding_has_ty!(ast::Parameter);
-impl_binding_has_ty!(ast::ParameterWithDefault);
+impl_definition_has_ty!(ast::StmtFunctionDef);
+impl_definition_has_ty!(ast::StmtClassDef);
+impl_definition_has_ty!(ast::Alias);
+impl_definition_has_ty!(ast::Parameter);
+impl_definition_has_ty!(ast::ParameterWithDefault);

 #[cfg(test)]
 mod tests {
--- a/crates/red_knot_python_semantic/src/site_packages.rs
+++ b/crates/red_knot_python_semantic/src/site_packages.rs
@@ -192,7 +192,7 @@ impl VirtualEnvironment {
            } else {
                tracing::warn!(
                    "Failed to resolve `sys.prefix` of the system Python installation \
-from the `home` value in the `pyvenv.cfg` file at `{}`. \
+from the `home` value in the `pyvenv.cfg` file at '{}'. \
 System site-packages will not be used for module resolution.",
                    venv_path.join("pyvenv.cfg")
                );
@@ -426,7 +426,7 @@ impl Deref for SysPrefixPath {

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

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

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

--- a/crates/red_knot_python_semantic/src/stdlib.rs
+++ b/crates/red_knot_python_semantic/src/stdlib.rs
@@ -1,87 +0,0 @@
-use crate::module_name::ModuleName;
-use crate::module_resolver::resolve_module;
-use crate::semantic_index::global_scope;
-use crate::semantic_index::symbol::ScopeId;
-use crate::types::{global_symbol_ty, Type};
-use crate::Db;
-
-/// Enumeration of various core stdlib modules, for which we have dedicated Salsa queries.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum CoreStdlibModule {
-    Builtins,
-    Types,
-    Typeshed,
-    TypingExtensions,
-}
-
-impl CoreStdlibModule {
-    fn name(self) -> ModuleName {
-        let module_name = match self {
-            Self::Builtins => "builtins",
-            Self::Types => "types",
-            Self::Typeshed => "_typeshed",
-            Self::TypingExtensions => "typing_extensions",
-        };
-        ModuleName::new_static(module_name)
-            .unwrap_or_else(|| panic!("{module_name} should be a valid module name!"))
-    }
-}
-
-/// Lookup the type of `symbol` in a given core module
-///
-/// Returns `Unbound` if the given core module cannot be resolved for some reason
-fn core_module_symbol_ty<'db>(
-    db: &'db dyn Db,
-    core_module: CoreStdlibModule,
-    symbol: &str,
-) -> Type<'db> {
-    resolve_module(db, core_module.name())
-        .map(|module| global_symbol_ty(db, module.file(), symbol))
-        .unwrap_or(Type::Unbound)
-}
-
-/// Lookup the type of `symbol` in the builtins namespace.
-///
-/// Returns `Unbound` if the `builtins` module isn't available for some reason.
-#[inline]
-pub(crate) fn builtins_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
-    core_module_symbol_ty(db, CoreStdlibModule::Builtins, symbol)
-}
-
-/// Lookup the type of `symbol` in the `types` module namespace.
-///
-/// Returns `Unbound` if the `types` module isn't available for some reason.
-#[inline]
-pub(crate) fn types_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
-    core_module_symbol_ty(db, CoreStdlibModule::Types, symbol)
-}
-
-/// Lookup the type of `symbol` in the `_typeshed` module namespace.
-///
-/// Returns `Unbound` if the `_typeshed` module isn't available for some reason.
-#[inline]
-pub(crate) fn typeshed_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
-    core_module_symbol_ty(db, CoreStdlibModule::Typeshed, symbol)
-}
-
-/// Lookup the type of `symbol` in the `typing_extensions` module namespace.
-///
-/// Returns `Unbound` if the `typing_extensions` module isn't available for some reason.
-#[inline]
-pub(crate) fn typing_extensions_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
-    core_module_symbol_ty(db, CoreStdlibModule::TypingExtensions, symbol)
-}
-
-/// Get the scope of a core stdlib module.
-///
-/// Can return `None` if a custom typeshed is used that is missing the core module in question.
-fn core_module_scope(db: &dyn Db, core_module: CoreStdlibModule) -> Option<ScopeId<'_>> {
-    resolve_module(db, core_module.name()).map(|module| global_scope(db, module.file()))
-}
-
-/// Get the `builtins` module scope.
-///
-/// Can return `None` if a custom typeshed is used that is missing `builtins.pyi`.
-pub(crate) fn builtins_module_scope(db: &dyn Db) -> Option<ScopeId<'_>> {
-    core_module_scope(db, CoreStdlibModule::Builtins)
-}
--- a/crates/red_knot_python_semantic/src/types.rs
+++ b/crates/red_knot_python_semantic/src/types.rs
--- a/crates/red_knot_python_semantic/src/types/builder.rs
+++ b/crates/red_knot_python_semantic/src/types/builder.rs
@@ -25,12 +25,15 @@
 //!   * No type in an intersection can be a supertype of any other type in the intersection (just
 //!     eliminate the supertype from the intersection).
 //!   * An intersection containing two non-overlapping types should simplify to [`Type::Never`].
-use crate::types::{builtins_symbol_ty, IntersectionType, Type, UnionType};
+
+use crate::types::{IntersectionType, Type, UnionType};
 use crate::{Db, FxOrderSet};
-use smallvec::SmallVec;
+use ordermap::set::MutableValues;
+
+use super::builtins_symbol_ty_by_name;

 pub(crate) struct UnionBuilder<'db> {
-    elements: Vec<Type<'db>>,
+    elements: FxOrderSet<Type<'db>>,
    db: &'db dyn Db,
 }

@@ -38,7 +41,7 @@ impl<'db> UnionBuilder<'db> {
    pub(crate) fn new(db: &'db dyn Db) -> Self {
        Self {
            db,
-            elements: vec![],
+            elements: FxOrderSet::default(),
        }
    }

@@ -46,70 +49,47 @@ impl<'db> UnionBuilder<'db> {
    pub(crate) fn add(mut self, ty: Type<'db>) -> Self {
        match ty {
            Type::Union(union) => {
-                let new_elements = union.elements(self.db);
-                self.elements.reserve(new_elements.len());
-                for element in new_elements {
-                    self = self.add(*element);
-                }
+                self.elements.extend(union.elements(self.db));
            }
            Type::Never => {}
            _ => {
-                let bool_pair = if let Type::BooleanLiteral(b) = ty {
-                    Some(Type::BooleanLiteral(!b))
-                } else {
-                    None
-                };
-
-                let mut to_add = ty;
-                let mut to_remove = SmallVec::<[usize; 2]>::new();
-                for (index, element) in self.elements.iter().enumerate() {
-                    if Some(*element) == bool_pair {
-                        to_add = builtins_symbol_ty(self.db, "bool");
-                        to_remove.push(index);
-                        // The type we are adding is a BooleanLiteral, which doesn't have any
-                        // subtypes. And we just found that the union already contained our
-                        // mirror-image BooleanLiteral, so it can't also contain bool or any
-                        // supertype of bool. Therefore, we are done.
-                        break;
-                    }
-                    if ty.is_subtype_of(self.db, *element) {
-                        return self;
-                    } else if element.is_subtype_of(self.db, ty) {
-                        to_remove.push(index);
-                    }
-                }
-
-                match to_remove[..] {
-                    [] => self.elements.push(to_add),
-                    [index] => self.elements[index] = to_add,
-                    _ => {
-                        let mut current_index = 0;
-                        let mut to_remove = to_remove.into_iter();
-                        let mut next_to_remove_index = to_remove.next();
-                        self.elements.retain(|_| {
-                            let retain = if Some(current_index) == next_to_remove_index {
-                                next_to_remove_index = to_remove.next();
-                                false
-                            } else {
-                                true
-                            };
-                            current_index += 1;
-                            retain
-                        });
-                        self.elements.push(to_add);
-                    }
-                }
+                self.elements.insert(ty);
            }
        }

        self
    }

-    pub(crate) fn build(self) -> Type<'db> {
+    /// Performs the following normalizations:
+    ///     - Replaces `Literal[True,False]` with `bool`.
+    ///     - TODO For enums `E` with members `X1`,...,`Xn`, replaces
+    ///     `Literal[E.X1,...,E.Xn]` with `E`.
+    fn simplify(&mut self) {
+        if let Some(true_index) = self.elements.get_index_of(&Type::BooleanLiteral(true)) {
+            if self.elements.contains(&Type::BooleanLiteral(false)) {
+                *self.elements.get_index_mut2(true_index).unwrap() =
+                    builtins_symbol_ty_by_name(self.db, "bool");
+                self.elements.remove(&Type::BooleanLiteral(false));
+            }
+        }
+    }
+
+    pub(crate) fn build(mut self) -> Type<'db> {
        match self.elements.len() {
            0 => Type::Never,
            1 => self.elements[0],
-            _ => Type::Union(UnionType::new(self.db, self.elements.into())),
+            _ => {
+                self.simplify();
+
+                match self.elements.len() {
+                    0 => Type::Never,
+                    1 => self.elements[0],
+                    _ => {
+                        self.elements.shrink_to_fit();
+                        Type::Union(UnionType::new(self.db, self.elements))
+                    }
+                }
+            }
        }
    }
 }
@@ -192,12 +172,11 @@ impl<'db> IntersectionBuilder<'db> {
        if self.intersections.len() == 1 {
            self.intersections.pop().unwrap().build(self.db)
        } else {
-            UnionType::from_elements(
-                self.db,
-                self.intersections
-                    .into_iter()
-                    .map(|inner| inner.build(self.db)),
-            )
+            let mut builder = UnionBuilder::new(self.db);
+            for inner in self.intersections {
+                builder = builder.add(inner.build(self.db));
+            }
+            builder.build()
        }
    }
 }
@@ -215,7 +194,6 @@ impl<'db> InnerIntersectionBuilder<'db> {

    /// Adds a positive type to this intersection.
    fn add_positive(&mut self, db: &'db dyn Db, ty: Type<'db>) {
-        // TODO `Any`/`Unknown`/`Todo` actually should not self-cancel
        match ty {
            Type::Intersection(inter) => {
                let pos = inter.positive(db);
@@ -235,7 +213,7 @@ impl<'db> InnerIntersectionBuilder<'db> {

    /// Adds a negative type to this intersection.
    fn add_negative(&mut self, db: &'db dyn Db, ty: Type<'db>) {
-        // TODO `Any`/`Unknown`/`Todo` actually should not self-cancel
+        // TODO Any/Unknown actually should not self-cancel
        match ty {
            Type::Intersection(intersection) => {
                let pos = intersection.negative(db);
@@ -296,14 +274,20 @@ impl<'db> InnerIntersectionBuilder<'db> {

 #[cfg(test)]
 mod tests {
-    use super::{IntersectionBuilder, IntersectionType, Type, UnionType};
+    use super::{IntersectionBuilder, IntersectionType, Type, UnionBuilder, UnionType};
    use crate::db::tests::TestDb;
    use crate::program::{Program, SearchPathSettings};
    use crate::python_version::PythonVersion;
-    use crate::types::{builtins_symbol_ty, UnionBuilder};
+    use crate::types::builtins_symbol_ty_by_name;
    use crate::ProgramSettings;
    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};

+    impl<'db> UnionType<'db> {
+        fn elements_vec(self, db: &'db TestDb) -> Vec<Type<'db>> {
+            self.elements(db).into_iter().copied().collect()
+        }
+    }
+
    fn setup_db() -> TestDb {
        let db = TestDb::new();

@@ -329,16 +313,21 @@ mod tests {
        let db = setup_db();
        let t0 = Type::IntLiteral(0);
        let t1 = Type::IntLiteral(1);
-        let union = UnionType::from_elements(&db, [t0, t1]).expect_union();
+        let union = UnionBuilder::new(&db)
+            .add(t0)
+            .add(t1)
+            .build()
+            .expect_union();

-        assert_eq!(union.elements(&db), &[t0, t1]);
+        assert_eq!(union.elements_vec(&db), &[t0, t1]);
    }

    #[test]
    fn build_union_single() {
        let db = setup_db();
        let t0 = Type::IntLiteral(0);
-        let ty = UnionType::from_elements(&db, [t0]);
+        let ty = UnionBuilder::new(&db).add(t0).build();
+
        assert_eq!(ty, t0);
    }

@@ -346,6 +335,7 @@ mod tests {
    fn build_union_empty() {
        let db = setup_db();
        let ty = UnionBuilder::new(&db).build();
+
        assert_eq!(ty, Type::Never);
    }

@@ -353,25 +343,37 @@ mod tests {
    fn build_union_never() {
        let db = setup_db();
        let t0 = Type::IntLiteral(0);
-        let ty = UnionType::from_elements(&db, [t0, Type::Never]);
+        let ty = UnionBuilder::new(&db).add(t0).add(Type::Never).build();
+
        assert_eq!(ty, t0);
    }

    #[test]
    fn build_union_bool() {
        let db = setup_db();
-        let bool_ty = builtins_symbol_ty(&db, "bool");
+        let bool_ty = builtins_symbol_ty_by_name(&db, "bool");

        let t0 = Type::BooleanLiteral(true);
        let t1 = Type::BooleanLiteral(true);
        let t2 = Type::BooleanLiteral(false);
        let t3 = Type::IntLiteral(17);

-        let union = UnionType::from_elements(&db, [t0, t1, t3]).expect_union();
-        assert_eq!(union.elements(&db), &[t0, t3]);
+        let union = UnionBuilder::new(&db)
+            .add(t0)
+            .add(t1)
+            .add(t3)
+            .build()
+            .expect_union();
+        assert_eq!(union.elements_vec(&db), &[t0, t3]);
+        let union = UnionBuilder::new(&db)
+            .add(t0)
+            .add(t1)
+            .add(t2)
+            .add(t3)
+            .build()
+            .expect_union();

-        let union = UnionType::from_elements(&db, [t0, t1, t2, t3]).expect_union();
-        assert_eq!(union.elements(&db), &[bool_ty, t3]);
+        assert_eq!(union.elements_vec(&db), &[bool_ty, t3]);
    }

    #[test]
@@ -380,47 +382,14 @@ mod tests {
        let t0 = Type::IntLiteral(0);
        let t1 = Type::IntLiteral(1);
        let t2 = Type::IntLiteral(2);
-        let u1 = UnionType::from_elements(&db, [t0, t1]);
-        let union = UnionType::from_elements(&db, [u1, t2]).expect_union();
+        let u1 = UnionBuilder::new(&db).add(t0).add(t1).build();
+        let union = UnionBuilder::new(&db)
+            .add(u1)
+            .add(t2)
+            .build()
+            .expect_union();

-        assert_eq!(union.elements(&db), &[t0, t1, t2]);
-    }
-
-    #[test]
-    fn build_union_simplify_subtype() {
-        let db = setup_db();
-        let t0 = Type::builtin_str_instance(&db);
-        let t1 = Type::LiteralString;
-        let u0 = UnionType::from_elements(&db, [t0, t1]);
-        let u1 = UnionType::from_elements(&db, [t1, t0]);
-
-        assert_eq!(u0, t0);
-        assert_eq!(u1, t0);
-    }
-
-    #[test]
-    fn build_union_no_simplify_unknown() {
-        let db = setup_db();
-        let t0 = Type::builtin_str_instance(&db);
-        let t1 = Type::Unknown;
-        let u0 = UnionType::from_elements(&db, [t0, t1]);
-        let u1 = UnionType::from_elements(&db, [t1, t0]);
-
-        assert_eq!(u0.expect_union().elements(&db), &[t0, t1]);
-        assert_eq!(u1.expect_union().elements(&db), &[t1, t0]);
-    }
-
-    #[test]
-    fn build_union_subsume_multiple() {
-        let db = setup_db();
-        let str_ty = Type::builtin_str_instance(&db);
-        let int_ty = Type::builtin_int_instance(&db);
-        let object_ty = builtins_symbol_ty(&db, "object").to_instance(&db);
-        let unknown_ty = Type::Unknown;
-
-        let u0 = UnionType::from_elements(&db, [str_ty, unknown_ty, int_ty, object_ty]);
-
-        assert_eq!(u0.expect_union().elements(&db), &[unknown_ty, object_ty]);
+        assert_eq!(union.elements_vec(&db), &[t0, t1, t2]);
    }

    impl<'db> IntersectionType<'db> {
@@ -494,14 +463,14 @@ mod tests {
        let t0 = Type::IntLiteral(0);
        let t1 = Type::IntLiteral(1);
        let ta = Type::Any;
-        let u0 = UnionType::from_elements(&db, [t0, t1]);
+        let u0 = UnionBuilder::new(&db).add(t0).add(t1).build();

        let union = IntersectionBuilder::new(&db)
            .add_positive(ta)
            .add_positive(u0)
            .build()
            .expect_union();
-        let [Type::Intersection(i0), Type::Intersection(i1)] = union.elements(&db)[..] else {
+        let [Type::Intersection(i0), Type::Intersection(i1)] = union.elements_vec(&db)[..] else {
            panic!("expected a union of two intersections");
        };
        assert_eq!(i0.pos_vec(&db), &[ta, t0]);
--- a/crates/red_knot_python_semantic/src/types/display.rs
+++ b/crates/red_knot_python_semantic/src/types/display.rs
@@ -1,20 +1,19 @@
 //! Display implementations for types.

-use std::fmt::{self, Display, Formatter};
+use std::fmt::{Display, Formatter};

-use ruff_db::display::FormatterJoinExtension;
 use ruff_python_ast::str::Quote;
 use ruff_python_literal::escape::AsciiEscape;

 use crate::types::{IntersectionType, Type, UnionType};
-use crate::Db;
-use rustc_hash::FxHashMap;
+use crate::{Db, FxOrderMap};

 impl<'db> Type<'db> {
-    pub fn display(&self, db: &'db dyn Db) -> DisplayType {
+    pub fn display(&'db self, db: &'db dyn Db) -> DisplayType<'db> {
        DisplayType { ty: self, db }
    }
-    fn representation(self, db: &'db dyn Db) -> DisplayRepresentation<'db> {
+
+    fn representation(&'db self, db: &'db dyn Db) -> DisplayRepresentation<'db> {
        DisplayRepresentation { db, ty: self }
    }
 }
@@ -26,7 +25,7 @@ pub struct DisplayType<'db> {
 }

 impl Display for DisplayType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let representation = self.ty.representation(self.db);
        if matches!(
            self.ty,
@@ -37,16 +36,16 @@ impl Display for DisplayType<'_> {
                | Type::Class(_)
                | Type::Function(_)
        ) {
-            write!(f, "Literal[{representation}]")
+            write!(f, "Literal[{representation}]",)
        } else {
            representation.fmt(f)
        }
    }
 }

-impl fmt::Debug for DisplayType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        Display::fmt(self, f)
+impl std::fmt::Debug for DisplayType<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
    }
 }

@@ -54,21 +53,18 @@ impl fmt::Debug for DisplayType<'_> {
 /// `Literal[<repr>]` or `Literal[<repr1>, <repr2>]` for literal types or as `<repr>` for
 /// non literals
 struct DisplayRepresentation<'db> {
-    ty: Type<'db>,
+    ty: &'db Type<'db>,
    db: &'db dyn Db,
 }

-impl Display for DisplayRepresentation<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+impl std::fmt::Display for DisplayRepresentation<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self.ty {
            Type::Any => f.write_str("Any"),
            Type::Never => f.write_str("Never"),
            Type::Unknown => f.write_str("Unknown"),
            Type::Unbound => f.write_str("Unbound"),
            Type::None => f.write_str("None"),
-            // `[Type::Todo]`'s display should be explicit that is not a valid display of
-            // any other type
-            Type::Todo => f.write_str("@Todo"),
            Type::Module(file) => {
                write!(f, "<module '{:?}'>", file.path(self.db))
            }
@@ -78,8 +74,8 @@ impl Display for DisplayRepresentation<'_> {
            Type::Function(function) => f.write_str(function.name(self.db)),
            Type::Union(union) => union.display(self.db).fmt(f),
            Type::Intersection(intersection) => intersection.display(self.db).fmt(f),
-            Type::IntLiteral(n) => n.fmt(f),
-            Type::BooleanLiteral(boolean) => f.write_str(if boolean { "True" } else { "False" }),
+            Type::IntLiteral(n) => write!(f, "{n}"),
+            Type::BooleanLiteral(boolean) => f.write_str(if *boolean { "True" } else { "False" }),
            Type::StringLiteral(string) => {
                write!(f, r#""{}""#, string.value(self.db).replace('"', r#"\""#))
            }
@@ -90,16 +86,6 @@ impl Display for DisplayRepresentation<'_> {

                escape.bytes_repr().write(f)
            }
-            Type::Tuple(tuple) => {
-                f.write_str("tuple[")?;
-                let elements = tuple.elements(self.db);
-                if elements.is_empty() {
-                    f.write_str("()")?;
-                } else {
-                    elements.display(self.db).fmt(f)?;
-                }
-                f.write_str("]")
-            }
        }
    }
 }
@@ -116,11 +102,11 @@ struct DisplayUnionType<'db> {
 }

 impl Display for DisplayUnionType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let elements = self.ty.elements(self.db);

        // Group literal types by kind.
-        let mut grouped_literals = FxHashMap::default();
+        let mut grouped_literals = FxOrderMap::default();

        for element in elements {
            if let Ok(literal_kind) = LiteralTypeKind::try_from(*element) {
@@ -131,26 +117,42 @@ impl Display for DisplayUnionType<'_> {
            }
        }

-        let mut join = f.join(" | ");
+        let mut first = true;

-        for element in elements {
-            if let Ok(literal_kind) = LiteralTypeKind::try_from(*element) {
+        // Print all types, but write all literals together (while preserving their position).
+        for ty in elements {
+            if let Ok(literal_kind) = LiteralTypeKind::try_from(*ty) {
                let Some(mut literals) = grouped_literals.remove(&literal_kind) else {
                    continue;
                };
+
+                if !first {
+                    f.write_str(" | ")?;
+                };
+
+                f.write_str("Literal[")?;
+
                if literal_kind == LiteralTypeKind::IntLiteral {
                    literals.sort_unstable_by_key(|ty| ty.expect_int_literal());
                }
-                join.entry(&DisplayLiteralGroup {
-                    literals,
-                    db: self.db,
-                });
-            } else {
-                join.entry(&element.display(self.db));
-            }
-        }

-        join.finish()?;
+                for (i, literal_ty) in literals.iter().enumerate() {
+                    if i > 0 {
+                        f.write_str(", ")?;
+                    }
+                    literal_ty.representation(self.db).fmt(f)?;
+                }
+                f.write_str("]")?;
+            } else {
+                if !first {
+                    f.write_str(" | ")?;
+                };
+
+                ty.display(self.db).fmt(f)?;
+            }
+
+            first = false;
+        }

        debug_assert!(grouped_literals.is_empty());

@@ -158,24 +160,9 @@ impl Display for DisplayUnionType<'_> {
    }
 }

-impl fmt::Debug for DisplayUnionType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        Display::fmt(self, f)
-    }
-}
-
-struct DisplayLiteralGroup<'db> {
-    literals: Vec<Type<'db>>,
-    db: &'db dyn Db,
-}
-
-impl Display for DisplayLiteralGroup<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        f.write_str("Literal[")?;
-        f.join(", ")
-            .entries(self.literals.iter().map(|ty| ty.representation(self.db)))
-            .finish()?;
-        f.write_str("]")
+impl std::fmt::Debug for DisplayUnionType<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
    }
 }

@@ -215,77 +202,31 @@ struct DisplayIntersectionType<'db> {
 }

 impl Display for DisplayIntersectionType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        let tys = self
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut first = true;
+        for (neg, ty) in self
            .ty
            .positive(self.db)
            .iter()
-            .map(|&ty| DisplayMaybeNegatedType {
-                ty,
-                db: self.db,
-                negated: false,
-            })
-            .chain(
-                self.ty
-                    .negative(self.db)
-                    .iter()
-                    .map(|&ty| DisplayMaybeNegatedType {
-                        ty,
-                        db: self.db,
-                        negated: true,
-                    }),
-            );
-        f.join(" & ").entries(tys).finish()
-    }
-}
-
-impl fmt::Debug for DisplayIntersectionType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        Display::fmt(self, f)
-    }
-}
-
-struct DisplayMaybeNegatedType<'db> {
-    ty: Type<'db>,
-    db: &'db dyn Db,
-    negated: bool,
-}
-
-impl<'db> Display for DisplayMaybeNegatedType<'db> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        if self.negated {
-            f.write_str("~")?;
+            .map(|ty| (false, ty))
+            .chain(self.ty.negative(self.db).iter().map(|ty| (true, ty)))
+        {
+            if !first {
+                f.write_str(" & ")?;
+            };
+            first = false;
+            if neg {
+                f.write_str("~")?;
+            };
+            write!(f, "{}", ty.display(self.db))?;
        }
-        self.ty.display(self.db).fmt(f)
+        Ok(())
    }
 }

-pub(crate) trait TypeArrayDisplay<'db> {
-    fn display(&self, db: &'db dyn Db) -> DisplayTypeArray;
-}
-
-impl<'db> TypeArrayDisplay<'db> for Box<[Type<'db>]> {
-    fn display(&self, db: &'db dyn Db) -> DisplayTypeArray {
-        DisplayTypeArray { types: self, db }
-    }
-}
-
-impl<'db> TypeArrayDisplay<'db> for Vec<Type<'db>> {
-    fn display(&self, db: &'db dyn Db) -> DisplayTypeArray {
-        DisplayTypeArray { types: self, db }
-    }
-}
-
-pub(crate) struct DisplayTypeArray<'b, 'db> {
-    types: &'b [Type<'db>],
-    db: &'db dyn Db,
-}
-
-impl<'db> Display for DisplayTypeArray<'_, 'db> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        f.join(", ")
-            .entries(self.types.iter().map(|ty| ty.display(self.db)))
-            .finish()
+impl std::fmt::Debug for DisplayIntersectionType<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
    }
 }

@@ -295,7 +236,9 @@ mod tests {
    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};

    use crate::db::tests::TestDb;
-    use crate::types::{global_symbol_ty, BytesLiteralType, StringLiteralType, Type, UnionType};
+    use crate::types::{
+        global_symbol_ty_by_name, BytesLiteralType, StringLiteralType, Type, UnionBuilder,
+    };
    use crate::{Program, ProgramSettings, PythonVersion, SearchPathSettings};

    fn setup_db() -> TestDb {
@@ -335,25 +278,28 @@ mod tests {
            class B: ...
            ",
        )?;
-        let mod_file = system_path_to_file(&db, "src/main.py").expect("file to exist");
+        let mod_file = system_path_to_file(&db, "src/main.py").expect("Expected file to exist.");

-        let union_elements = &[
+        let vec: Vec<Type<'_>> = vec![
            Type::Unknown,
            Type::IntLiteral(-1),
-            global_symbol_ty(&db, mod_file, "A"),
+            global_symbol_ty_by_name(&db, mod_file, "A"),
            Type::StringLiteral(StringLiteralType::new(&db, Box::from("A"))),
            Type::BytesLiteral(BytesLiteralType::new(&db, Box::from([0]))),
            Type::BytesLiteral(BytesLiteralType::new(&db, Box::from([7]))),
            Type::IntLiteral(0),
            Type::IntLiteral(1),
            Type::StringLiteral(StringLiteralType::new(&db, Box::from("B"))),
-            global_symbol_ty(&db, mod_file, "foo"),
-            global_symbol_ty(&db, mod_file, "bar"),
-            global_symbol_ty(&db, mod_file, "B"),
+            global_symbol_ty_by_name(&db, mod_file, "foo"),
+            global_symbol_ty_by_name(&db, mod_file, "bar"),
+            global_symbol_ty_by_name(&db, mod_file, "B"),
            Type::BooleanLiteral(true),
            Type::None,
        ];
-        let union = UnionType::from_elements(&db, union_elements).expect_union();
+        let builder = vec.iter().fold(UnionBuilder::new(&db), |builder, literal| {
+            builder.add(*literal)
+        });
+        let union = builder.build().expect_union();
        let display = format!("{}", union.display(&db));
        assert_eq!(
            display,
--- a/crates/red_knot_python_semantic/src/types/infer.rs
+++ b/crates/red_knot_python_semantic/src/types/infer.rs
--- a/crates/red_knot_python_semantic/src/types/narrow.rs
+++ b/crates/red_knot_python_semantic/src/types/narrow.rs
@@ -1,10 +1,9 @@
 use crate::semantic_index::ast_ids::HasScopedAstId;
-use crate::semantic_index::constraint::{Constraint, PatternConstraint};
 use crate::semantic_index::definition::Definition;
 use crate::semantic_index::expression::Expression;
 use crate::semantic_index::symbol::{ScopeId, ScopedSymbolId, SymbolTable};
 use crate::semantic_index::symbol_table;
-use crate::types::{infer_expression_types, IntersectionBuilder, Type};
+use crate::types::{infer_expression_types, IntersectionBuilder, Type, TypeInference};
 use crate::Db;
 use ruff_python_ast as ast;
 use rustc_hash::FxHashMap;
@@ -28,114 +27,62 @@ use std::sync::Arc;
 /// constraint is applied to that definition, so we'd just return `None`.
 pub(crate) fn narrowing_constraint<'db>(
    db: &'db dyn Db,
-    constraint: Constraint<'db>,
+    test: Expression<'db>,
    definition: Definition<'db>,
 ) -> Option<Type<'db>> {
-    match constraint {
-        Constraint::Expression(expression) => {
-            all_narrowing_constraints_for_expression(db, expression)
-                .get(&definition.symbol(db))
-                .copied()
-        }
-        Constraint::Pattern(pattern) => all_narrowing_constraints_for_pattern(db, pattern)
-            .get(&definition.symbol(db))
-            .copied(),
-    }
+    all_narrowing_constraints(db, test)
+        .get(&definition.symbol(db))
+        .copied()
 }

 #[salsa::tracked(return_ref)]
-fn all_narrowing_constraints_for_pattern<'db>(
+fn all_narrowing_constraints<'db>(
    db: &'db dyn Db,
-    pattern: PatternConstraint<'db>,
+    test: Expression<'db>,
 ) -> NarrowingConstraints<'db> {
-    NarrowingConstraintsBuilder::new(db, Constraint::Pattern(pattern)).finish()
-}
-
-#[salsa::tracked(return_ref)]
-fn all_narrowing_constraints_for_expression<'db>(
-    db: &'db dyn Db,
-    expression: Expression<'db>,
-) -> NarrowingConstraints<'db> {
-    NarrowingConstraintsBuilder::new(db, Constraint::Expression(expression)).finish()
+    NarrowingConstraintsBuilder::new(db, test).finish()
 }

 type NarrowingConstraints<'db> = FxHashMap<ScopedSymbolId, Type<'db>>;

 struct NarrowingConstraintsBuilder<'db> {
    db: &'db dyn Db,
-    constraint: Constraint<'db>,
+    expression: Expression<'db>,
    constraints: NarrowingConstraints<'db>,
 }

 impl<'db> NarrowingConstraintsBuilder<'db> {
-    fn new(db: &'db dyn Db, constraint: Constraint<'db>) -> Self {
+    fn new(db: &'db dyn Db, expression: Expression<'db>) -> Self {
        Self {
            db,
-            constraint,
+            expression,
            constraints: NarrowingConstraints::default(),
        }
    }

    fn finish(mut self) -> NarrowingConstraints<'db> {
-        match self.constraint {
-            Constraint::Expression(expression) => self.evaluate_expression_constraint(expression),
-            Constraint::Pattern(pattern) => self.evaluate_pattern_constraint(pattern),
+        if let ast::Expr::Compare(expr_compare) = self.expression.node_ref(self.db).node() {
+            self.add_expr_compare(expr_compare);
        }
+        // TODO other test expression kinds

        self.constraints.shrink_to_fit();
        self.constraints
    }

-    fn evaluate_expression_constraint(&mut self, expression: Expression<'db>) {
-        if let ast::Expr::Compare(expr_compare) = expression.node_ref(self.db).node() {
-            self.add_expr_compare(expr_compare, expression);
-        }
-        // TODO other test expression kinds
-    }
-
-    fn evaluate_pattern_constraint(&mut self, pattern: PatternConstraint<'db>) {
-        let subject = pattern.subject(self.db);
-
-        match pattern.pattern(self.db).node() {
-            ast::Pattern::MatchValue(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchSingleton(singleton_pattern) => {
-                self.add_match_pattern_singleton(subject, singleton_pattern);
-            }
-            ast::Pattern::MatchSequence(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchMapping(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchClass(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchStar(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchAs(_) => {
-                // TODO
-            }
-            ast::Pattern::MatchOr(_) => {
-                // TODO
-            }
-        }
-    }
-
    fn symbols(&self) -> Arc<SymbolTable> {
        symbol_table(self.db, self.scope())
    }

    fn scope(&self) -> ScopeId<'db> {
-        match self.constraint {
-            Constraint::Expression(expression) => expression.scope(self.db),
-            Constraint::Pattern(pattern) => pattern.scope(self.db),
-        }
+        self.expression.scope(self.db)
    }

-    fn add_expr_compare(&mut self, expr_compare: &ast::ExprCompare, expression: Expression<'db>) {
+    fn inference(&self) -> &'db TypeInference<'db> {
+        infer_expression_types(self.db, self.expression)
+    }
+
+    fn add_expr_compare(&mut self, expr_compare: &ast::ExprCompare) {
        let ast::ExprCompare {
            range: _,
            left,
@@ -152,7 +99,7 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
            // SAFETY: we should always have a symbol for every Name node.
            let symbol = self.symbols().symbol_id_by_name(id).unwrap();
            let scope = self.scope();
-            let inference = infer_expression_types(self.db, expression);
+            let inference = self.inference();
            for (op, comparator) in std::iter::zip(&**ops, &**comparators) {
                let comp_ty = inference.expression_ty(comparator.scoped_ast_id(self.db, scope));
                if matches!(op, ast::CmpOp::IsNot) {
@@ -165,22 +112,4 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
            }
        }
    }
-
-    fn add_match_pattern_singleton(
-        &mut self,
-        subject: &ast::Expr,
-        pattern: &ast::PatternMatchSingleton,
-    ) {
-        if let Some(ast::ExprName { id, .. }) = subject.as_name_expr() {
-            // SAFETY: we should always have a symbol for every Name node.
-            let symbol = self.symbols().symbol_id_by_name(id).unwrap();
-
-            let ty = match pattern.value {
-                ast::Singleton::None => Type::None,
-                ast::Singleton::True => Type::BooleanLiteral(true),
-                ast::Singleton::False => Type::BooleanLiteral(false),
-            };
-            self.constraints.insert(symbol, ty);
-        }
-    }
 }
--- a/crates/red_knot_python_semantic/vendor/typeshed/LICENSE
+++ b/crates/red_knot_python_semantic/vendor/typeshed/LICENSE
--- a/crates/red_knot_python_semantic/vendor/typeshed/README.md
+++ b/crates/red_knot_python_semantic/vendor/typeshed/README.md
--- a/crates/red_knot_python_semantic/vendor/typeshed/source_commit.txt
+++ b/crates/red_knot_python_semantic/vendor/typeshed/source_commit.txt
@@ -0,0 +1 @@
+23d867efb2df6de5600f64656f1aa8a83e06109e
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/VERSIONS
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/VERSIONS
@@ -41,7 +41,7 @@ _json: 3.0-
 _locale: 3.0-
 _lsprof: 3.0-
 _markupbase: 3.0-
-_msi: 3.0-3.12
+_msi: 3.0-
 _operator: 3.4-
 _osx_support: 3.0-
 _posixsubprocess: 3.2-
@@ -161,8 +161,6 @@ importlib.metadata._meta: 3.10-
 importlib.metadata.diagnose: 3.13-
 importlib.readers: 3.10-
 importlib.resources: 3.7-
-importlib.resources._common: 3.11-
-importlib.resources._functional: 3.13-
 importlib.resources.abc: 3.11-
 importlib.resources.readers: 3.11-
 importlib.resources.simple: 3.11-
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/future.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/future.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/main.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/main.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_ast.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_ast.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_bisect.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_bisect.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_bootlocale.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_bootlocale.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_codecs.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_codecs.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_collections_abc.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_collections_abc.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_compat_pickle.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_compat_pickle.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_compression.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_compression.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_csv.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_csv.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_ctypes.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_ctypes.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_curses.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_curses.pyi
@@ -493,7 +493,7 @@ class _CursesWindow:
    def instr(self, y: int, x: int, n: int = ...) -> bytes: ...
    def is_linetouched(self, line: int, /) -> bool: ...
    def is_wintouched(self) -> bool: ...
-    def keypad(self, yes: bool, /) -> None: ...
+    def keypad(self, yes: bool) -> None: ...
    def leaveok(self, yes: bool) -> None: ...
    def move(self, new_y: int, new_x: int) -> None: ...
    def mvderwin(self, y: int, x: int) -> None: ...
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_decimal.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_decimal.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_dummy_thread.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_dummy_thread.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_dummy_threading.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_dummy_threading.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_heapq.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_heapq.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_imp.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_imp.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpchannels.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpchannels.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpqueues.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpqueues.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpreters.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_interpreters.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_json.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_json.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_locale.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_locale.pyi
@@ -0,0 +1,100 @@
+import sys
+from _typeshed import StrPath
+from collections.abc import Mapping
+
+LC_CTYPE: int
+LC_COLLATE: int
+LC_TIME: int
+LC_MONETARY: int
+LC_NUMERIC: int
+LC_ALL: int
+CHAR_MAX: int
+
+def setlocale(category: int, locale: str | None = None, /) -> str: ...
+def localeconv() -> Mapping[str, int | str | list[int]]: ...
+
+if sys.version_info >= (3, 11):
+    def getencoding() -> str: ...
+
+def strcoll(os1: str, os2: str, /) -> int: ...
+def strxfrm(string: str, /) -> str: ...
+
+# native gettext functions
+# https://docs.python.org/3/library/locale.html#access-to-message-catalogs
+# https://github.com/python/cpython/blob/f4c03484da59049eb62a9bf7777b963e2267d187/Modules/_localemodule.c#L626
+if sys.platform != "win32":
+    LC_MESSAGES: int
+
+    ABDAY_1: int
+    ABDAY_2: int
+    ABDAY_3: int
+    ABDAY_4: int
+    ABDAY_5: int
+    ABDAY_6: int
+    ABDAY_7: int
+
+    ABMON_1: int
+    ABMON_2: int
+    ABMON_3: int
+    ABMON_4: int
+    ABMON_5: int
+    ABMON_6: int
+    ABMON_7: int
+    ABMON_8: int
+    ABMON_9: int
+    ABMON_10: int
+    ABMON_11: int
+    ABMON_12: int
+
+    DAY_1: int
+    DAY_2: int
+    DAY_3: int
+    DAY_4: int
+    DAY_5: int
+    DAY_6: int
+    DAY_7: int
+
+    ERA: int
+    ERA_D_T_FMT: int
+    ERA_D_FMT: int
+    ERA_T_FMT: int
+
+    MON_1: int
+    MON_2: int
+    MON_3: int
+    MON_4: int
+    MON_5: int
+    MON_6: int
+    MON_7: int
+    MON_8: int
+    MON_9: int
+    MON_10: int
+    MON_11: int
+    MON_12: int
+
+    CODESET: int
+    D_T_FMT: int
+    D_FMT: int
+    T_FMT: int
+    T_FMT_AMPM: int
+    AM_STR: int
+    PM_STR: int
+
+    RADIXCHAR: int
+    THOUSEP: int
+    YESEXPR: int
+    NOEXPR: int
+    CRNCYSTR: int
+    ALT_DIGITS: int
+
+    def nl_langinfo(key: int, /) -> str: ...
+
+    # This is dependent on `libintl.h` which is a part of `gettext`
+    # system dependency. These functions might be missing.
+    # But, we always say that they are present.
+    def gettext(msg: str, /) -> str: ...
+    def dgettext(domain: str | None, msg: str, /) -> str: ...
+    def dcgettext(domain: str | None, msg: str, category: int, /) -> str: ...
+    def textdomain(domain: str | None, /) -> str: ...
+    def bindtextdomain(domain: str, dir: StrPath | None, /) -> str: ...
+    def bind_textdomain_codeset(domain: str, codeset: str | None, /) -> str | None: ...
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_lsprof.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_lsprof.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_markupbase.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_markupbase.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_msi.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_msi.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_operator.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_operator.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_osx_support.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_osx_support.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_posixsubprocess.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_posixsubprocess.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_py_abc.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_py_abc.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_pydecimal.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_pydecimal.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_random.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_random.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_sitebuiltins.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_sitebuiltins.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_socket.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_socket.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_stat.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_stat.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_thread.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_thread.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_threading_local.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_threading_local.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_tkinter.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_tkinter.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_tracemalloc.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_tracemalloc.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/README.md
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/README.md
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/init.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/init.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/dbapi.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/dbapi.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/importlib.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/importlib.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/wsgi.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/wsgi.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/xml.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_typeshed/xml.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_warnings.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_warnings.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_weakref.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_weakref.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_weakrefset.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_weakrefset.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_winapi.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/_winapi.pyi
@@ -99,20 +99,6 @@ if sys.platform == "win32":
    SEC_RESERVE: Final = 0x4000000
    SEC_WRITECOMBINE: Final = 0x40000000

-    if sys.version_info >= (3, 13):
-        STARTF_FORCEOFFFEEDBACK: Final = 0x80
-        STARTF_FORCEONFEEDBACK: Final = 0x40
-        STARTF_PREVENTPINNING: Final = 0x2000
-        STARTF_RUNFULLSCREEN: Final = 0x20
-        STARTF_TITLEISAPPID: Final = 0x1000
-        STARTF_TITLEISLINKNAME: Final = 0x800
-        STARTF_UNTRUSTEDSOURCE: Final = 0x8000
-        STARTF_USECOUNTCHARS: Final = 0x8
-        STARTF_USEFILLATTRIBUTE: Final = 0x10
-        STARTF_USEHOTKEY: Final = 0x200
-        STARTF_USEPOSITION: Final = 0x4
-        STARTF_USESIZE: Final = 0x2
-
    STARTF_USESHOWWINDOW: Final = 0x1
    STARTF_USESTDHANDLES: Final = 0x100

@@ -264,20 +250,6 @@ if sys.platform == "win32":
        def cancel(self) -> None: ...
        def getbuffer(self) -> bytes | None: ...

-    if sys.version_info >= (3, 13):
-        def BatchedWaitForMultipleObjects(
-            handle_seq: Sequence[int], wait_all: bool, milliseconds: int = 0xFFFFFFFF
-        ) -> list[int]: ...
-        def CreateEventW(security_attributes: int, manual_reset: bool, initial_state: bool, name: str | None) -> int: ...
-        def CreateMutexW(security_attributes: int, initial_owner: bool, name: str) -> int: ...
-        def GetLongPathName(path: str) -> str: ...
-        def GetShortPathName(path: str) -> str: ...
-        def OpenEventW(desired_access: int, inherit_handle: bool, name: str) -> int: ...
-        def OpenMutexW(desired_access: int, inherit_handle: bool, name: str) -> int: ...
-        def ReleaseMutex(mutex: int) -> None: ...
-        def ResetEvent(event: int) -> None: ...
-        def SetEvent(event: int) -> None: ...
-
    if sys.version_info >= (3, 12):
        def CopyFile2(existing_file_name: str, new_file_name: str, flags: int, progress_routine: int | None = None) -> int: ...
        def NeedCurrentDirectoryForExePath(exe_name: str, /) -> bool: ...
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/abc.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/abc.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/aifc.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/aifc.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/antigravity.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/antigravity.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/argparse.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/argparse.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/array.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/array.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/ast.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/ast.pyi
--- a/crates/red_knot_python_semantic/vendor/typeshed/stdlib/asynchat.pyi
+++ b/crates/red_knot_python_semantic/vendor/typeshed/stdlib/asynchat.pyi
--- a/Show More
+++ b/Show More