generate using cargo-dist

.editorconfig

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

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ env:
   CARGO_TERM_COLOR: always
   RUSTUP_MAX_RETRIES: 10
   PACKAGE_NAME: ruff
-  PYTHON_VERSION: "3.12"
+  PYTHON_VERSION: "3.11"
 
 jobs:
   determine_changes:
@@ -268,7 +268,6 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "fuzz -> target"
-          cache-all-crates: "true"
       - name: "Install cargo-binstall"
         uses: cargo-bins/cargo-binstall@main
         with:

.github/workflows/publish-playground.yml

@@ -47,7 +47,7 @@ jobs:
         working-directory: playground
       - name: "Deploy to Cloudflare Pages"
         if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@v3.12.1
+        uses: cloudflare/wrangler-action@v3.9.0
         with:
           apiToken: ${{ secrets.CF_API_TOKEN }}
           accountId: ${{ secrets.CF_ACCOUNT_ID }}

.github/workflows/release.yml

@@ -202,46 +202,15 @@ jobs:
           name: artifacts-dist-manifest
           path: dist-manifest.json
 
-  custom-publish-pypi:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-pypi.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "id-token": "write"
-      "packages": "write"
-
-  custom-publish-wasm:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-wasm.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "contents": "read"
-      "id-token": "write"
-      "packages": "write"
-
   # Create a GitHub Release while uploading all files to it
   announce:
     needs:
       - plan
       - host
-      - custom-publish-pypi
-      - custom-publish-wasm
     # use "always() && ..." to allow us to wait for all publish jobs while
     # still allowing individual publish jobs to skip themselves (for prereleases).
     # "host" however must run to completion, no skipping allowed!
-    if: ${{ always() && needs.host.result == 'success' && (needs.custom-publish-pypi.result == 'skipped' || needs.custom-publish-pypi.result == 'success') && (needs.custom-publish-wasm.result == 'skipped' || needs.custom-publish-wasm.result == 'success') }}
+    if: ${{ always() && needs.host.result == 'success' }}
     runs-on: "ubuntu-20.04"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.pre-commit-config.yaml

@@ -17,7 +17,7 @@ exclude: |
 
 repos:
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.23
+    rev: v0.21
     hooks:
       - id: validate-pyproject
 
@@ -51,15 +51,11 @@ repos:
       - id: blacken-docs
         args: ["--pyi", "--line-length", "130"]
         files: '^crates/.*/resources/mdtest/.*\.md'
-        exclude: |
-          (?x)^(
-            .*?invalid(_.+)*_syntax\.md
-          )$
         additional_dependencies:
           - black==24.10.0
 
   - repo: https://github.com/crate-ci/typos
-    rev: v1.27.3
+    rev: v1.26.0
     hooks:
       - id: typos
 
@@ -73,7 +69,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.7.4
+    rev: v0.7.0
     hooks:
       - id: ruff-format
       - id: ruff

CHANGELOG.md

@@ -1,91 +1,5 @@
 # Changelog
 
-## 0.7.4
-
-### Preview features
-
-- \[`flake8-datetimez`\] Detect usages of `datetime.max`/`datetime.min` (`DTZ901`) ([#14288](https://github.com/astral-sh/ruff/pull/14288))
-- \[`flake8-logging`\] Implement `root-logger-calls` (`LOG015`) ([#14302](https://github.com/astral-sh/ruff/pull/14302))
-- \[`flake8-no-pep420`\] Detect empty implicit namespace packages (`INP001`) ([#14236](https://github.com/astral-sh/ruff/pull/14236))
-- \[`flake8-pyi`\] Add "replace with `Self`" fix (`PYI019`) ([#14238](https://github.com/astral-sh/ruff/pull/14238))
-- \[`perflint`\] Implement quick-fix for `manual-list-comprehension` (`PERF401`) ([#13919](https://github.com/astral-sh/ruff/pull/13919))
-- \[`pylint`\] Implement `shallow-copy-environ` (`W1507`) ([#14241](https://github.com/astral-sh/ruff/pull/14241))
-- \[`ruff`\] Implement `none-not-at-end-of-union` (`RUF036`) ([#14314](https://github.com/astral-sh/ruff/pull/14314))
-- \[`ruff`\] Implementation `unsafe-markup-call` from `flake8-markupsafe` plugin (`RUF035`) ([#14224](https://github.com/astral-sh/ruff/pull/14224))
-- \[`ruff`\] Report problems for `attrs` dataclasses (`RUF008`, `RUF009`) ([#14327](https://github.com/astral-sh/ruff/pull/14327))
-
-### Rule changes
-
-- \[`flake8-boolean-trap`\] Exclude dunder methods that define operators (`FBT001`) ([#14203](https://github.com/astral-sh/ruff/pull/14203))
-- \[`flake8-pyi`\] Add "replace with `Self`" fix (`PYI034`) ([#14217](https://github.com/astral-sh/ruff/pull/14217))
-- \[`flake8-pyi`\] Always autofix `duplicate-union-members` (`PYI016`) ([#14270](https://github.com/astral-sh/ruff/pull/14270))
-- \[`flake8-pyi`\] Improve autofix for nested and mixed type unions for `unnecessary-type-union` (`PYI055`) ([#14272](https://github.com/astral-sh/ruff/pull/14272))
-- \[`flake8-pyi`\] Mark fix as unsafe when type annotation contains comments for `duplicate-literal-member` (`PYI062`) ([#14268](https://github.com/astral-sh/ruff/pull/14268))
-
-### Server
-
-- Use the current working directory to resolve settings from `ruff.configuration` ([#14352](https://github.com/astral-sh/ruff/pull/14352))
-
-### Bug fixes
-
-- Avoid conflicts between `PLC014` (`useless-import-alias`) and `I002` (`missing-required-import`) by considering `lint.isort.required-imports` for `PLC014` ([#14287](https://github.com/astral-sh/ruff/pull/14287))
-- \[`flake8-type-checking`\] Skip quoting annotation if it becomes invalid syntax (`TCH001`)
-- \[`flake8-pyi`\] Avoid using `typing.Self` in stub files pre-Python 3.11 (`PYI034`) ([#14230](https://github.com/astral-sh/ruff/pull/14230))
-- \[`flake8-pytest-style`\] Flag `pytest.raises` call with keyword argument `expected_exception` (`PT011`) ([#14298](https://github.com/astral-sh/ruff/pull/14298))
-- \[`flake8-simplify`\] Infer "unknown" truthiness for literal iterables whose items are all unpacks (`SIM222`) ([#14263](https://github.com/astral-sh/ruff/pull/14263))
-- \[`flake8-type-checking`\] Fix false positives for `typing.Annotated` (`TCH001`) ([#14311](https://github.com/astral-sh/ruff/pull/14311))
-- \[`pylint`\] Allow `await` at the top-level scope of a notebook (`PLE1142`) ([#14225](https://github.com/astral-sh/ruff/pull/14225))
-- \[`pylint`\] Fix miscellaneous issues in `await-outside-async` detection (`PLE1142`) ([#14218](https://github.com/astral-sh/ruff/pull/14218))
-- \[`pyupgrade`\] Avoid applying PEP 646 rewrites in invalid contexts (`UP044`) ([#14234](https://github.com/astral-sh/ruff/pull/14234))
-- \[`pyupgrade`\] Detect permutations in redundant open modes (`UP015`) ([#14255](https://github.com/astral-sh/ruff/pull/14255))
-- \[`refurb`\] Avoid triggering `hardcoded-string-charset` for reordered sets (`FURB156`) ([#14233](https://github.com/astral-sh/ruff/pull/14233))
-- \[`refurb`\] Further special cases added to `verbose-decimal-constructor` (`FURB157`) ([#14216](https://github.com/astral-sh/ruff/pull/14216))
-- \[`refurb`\] Use `UserString` instead of non-existent `UserStr` (`FURB189`) ([#14209](https://github.com/astral-sh/ruff/pull/14209))
-- \[`ruff`\] Avoid treating lowercase letters as `# noqa` codes (`RUF100`) ([#14229](https://github.com/astral-sh/ruff/pull/14229))
-- \[`ruff`\] Do not report when `Optional` has no type arguments (`RUF013`) ([#14181](https://github.com/astral-sh/ruff/pull/14181))
-
-### Documentation
-
-- Add "Notebook behavior" section for `F704`, `PLE1142` ([#14266](https://github.com/astral-sh/ruff/pull/14266))
-- Document comment policy around fix safety ([#14300](https://github.com/astral-sh/ruff/pull/14300))
-
-## 0.7.3
-
-### Preview features
-
-- Formatter: Disallow single-line implicit concatenated strings ([#13928](https://github.com/astral-sh/ruff/pull/13928))
-- \[`flake8-pyi`\] Include all Python file types for `PYI006` and `PYI066` ([#14059](https://github.com/astral-sh/ruff/pull/14059))
-- \[`flake8-simplify`\] Implement `split-of-static-string` (`SIM905`) ([#14008](https://github.com/astral-sh/ruff/pull/14008))
-- \[`refurb`\] Implement `subclass-builtin` (`FURB189`) ([#14105](https://github.com/astral-sh/ruff/pull/14105))
-- \[`ruff`\] Improve diagnostic messages and docs (`RUF031`, `RUF032`, `RUF034`) ([#14068](https://github.com/astral-sh/ruff/pull/14068))
-
-### Rule changes
-
-- Detect items that hash to same value in duplicate sets (`B033`, `PLC0208`) ([#14064](https://github.com/astral-sh/ruff/pull/14064))
-- \[`eradicate`\] Better detection of IntelliJ language injection comments (`ERA001`) ([#14094](https://github.com/astral-sh/ruff/pull/14094))
-- \[`flake8-pyi`\] Add autofix for `docstring-in-stub` (`PYI021`) ([#14150](https://github.com/astral-sh/ruff/pull/14150))
-- \[`flake8-pyi`\] Update `duplicate-literal-member` (`PYI062`) to alawys provide an autofix ([#14188](https://github.com/astral-sh/ruff/pull/14188))
-- \[`pyflakes`\] Detect items that hash to same value in duplicate dictionaries (`F601`) ([#14065](https://github.com/astral-sh/ruff/pull/14065))
-- \[`ruff`\] Fix false positive for decorators (`RUF028`) ([#14061](https://github.com/astral-sh/ruff/pull/14061))
-
-### Bug fixes
-
-- Avoid parsing joint rule codes as distinct codes in `# noqa` ([#12809](https://github.com/astral-sh/ruff/pull/12809))
-- \[`eradicate`\] ignore `# language=` in commented-out-code rule (ERA001) ([#14069](https://github.com/astral-sh/ruff/pull/14069))
-- \[`flake8-bugbear`\] - do not run `mutable-argument-default` on stubs (`B006`) ([#14058](https://github.com/astral-sh/ruff/pull/14058))
-- \[`flake8-builtins`\] Skip lambda expressions in `builtin-argument-shadowing (A002)` ([#14144](https://github.com/astral-sh/ruff/pull/14144))
-- \[`flake8-comprehension`\] Also remove trailing comma while fixing `C409` and `C419` ([#14097](https://github.com/astral-sh/ruff/pull/14097))
-- \[`flake8-simplify`\] Allow `open` without context manager in `return` statement (`SIM115`) ([#14066](https://github.com/astral-sh/ruff/pull/14066))
-- \[`pylint`\] Respect hash-equivalent literals in `iteration-over-set` (`PLC0208`) ([#14063](https://github.com/astral-sh/ruff/pull/14063))
-- \[`pylint`\] Update known dunder methods for Python 3.13 (`PLW3201`) ([#14146](https://github.com/astral-sh/ruff/pull/14146))
-- \[`pyupgrade`\] - ignore kwarg unpacking for `UP044` ([#14053](https://github.com/astral-sh/ruff/pull/14053))
-- \[`refurb`\] Parse more exotic decimal strings in `verbose-decimal-constructor` (`FURB157`) ([#14098](https://github.com/astral-sh/ruff/pull/14098))
-
-### Documentation
-
-- Add links to missing related options within rule documentations ([#13971](https://github.com/astral-sh/ruff/pull/13971))
-- Add rule short code to mkdocs tags to allow searching via rule codes ([#14040](https://github.com/astral-sh/ruff/pull/14040))
-
 ## 0.7.2
 
 ### Preview features

Cargo.toml

@@ -66,7 +66,6 @@ criterion = { version = "0.5.1", default-features = false }
 crossbeam = { version = "0.8.4" }
 dashmap = { version = "6.0.1" }
 dir-test = { version = "0.3.0" }
-dunce = { version = "1.0.5" }
 drop_bomb = { version = "0.1.5" }
 env_logger = { version = "0.11.0" }
 etcetera = { version = "0.8.0" }
@@ -82,7 +81,6 @@ hashbrown = { version = "0.15.0", default-features = false, features = [
 ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
 imperative = { version = "1.0.4" }
-indexmap = { version = "2.6.0" }
 indicatif = { version = "0.17.8" }
 indoc = { version = "2.0.4" }
 insta = { version = "1.35.1" }
@@ -103,7 +101,7 @@ matchit = { version = "0.8.1" }
 memchr = { version = "2.7.1" }
 mimalloc = { version = "0.1.39" }
 natord = { version = "1.0.9" }
-notify = { version = "7.0.0" }
+notify = { version = "6.1.1" }
 ordermap = { version = "0.5.0" }
 path-absolutize = { version = "3.1.1" }
 path-slash = { version = "0.2.1" }
@@ -137,7 +135,7 @@ strum_macros = { version = "0.26.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
-thiserror = { version = "2.0.0" }
+thiserror = { version = "1.0.58" }
 tikv-jemallocator = { version = "0.6.0" }
 toml = { version = "0.8.11" }
 tracing = { version = "0.1.40" }
@@ -295,7 +293,7 @@ build-local-artifacts = false
 # Local artifacts jobs to run in CI
 local-artifacts-jobs = ["./build-binaries", "./build-docker"]
 # Publish jobs to run in CI
-publish-jobs = ["./publish-pypi", "./publish-wasm"]
+# publish-jobs = ["./publish-pypi", "./publish-wasm"]
 # Post-announce jobs to run in CI
 post-announce-jobs = [
     "./notify-dependents",

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/0.7.4/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.7.4/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.7.2/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.7.2/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -170,7 +170,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.7.4
+  rev: v0.7.2
   hooks:
     # Run the linter.
     - id: ruff

_typos.toml

@@ -1,11 +1,6 @@
 [files]
 # https://github.com/crate-ci/typos/issues/868
-extend-exclude = [
-  "crates/red_knot_vendored/vendor/**/*",
-  "**/resources/**/*",
-  "**/snapshots/**/*",
-  "crates/red_knot_workspace/src/workspace/pyproject/package_name.rs"
-]
+extend-exclude = ["crates/red_knot_vendored/vendor/**/*", "**/resources/**/*", "**/snapshots/**/*"]
 
 [default.extend-words]
 "arange" = "arange"  # e.g. `numpy.arange`

crates/red_knot/Cargo.toml

@@ -34,7 +34,6 @@ tracing-tree = { workspace = true }
 [dev-dependencies]
 filetime = { workspace = true }
 tempfile = { workspace = true }
-ruff_db = { workspace = true, features = ["testing"] }
 
 [lints]
 workspace = true

crates/red_knot/src/main.rs

@@ -5,6 +5,8 @@ use anyhow::{anyhow, Context};
 use clap::Parser;
 use colored::Colorize;
 use crossbeam::channel as crossbeam_channel;
+use salsa::plumbing::ZalsaDatabase;
+
 use red_knot_python_semantic::SitePackages;
 use red_knot_server::run_server;
 use red_knot_workspace::db::RootDatabase;
@@ -12,9 +14,7 @@ use red_knot_workspace::watch;
 use red_knot_workspace::watch::WorkspaceWatcher;
 use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
-use ruff_db::diagnostic::Diagnostic;
 use ruff_db::system::{OsSystem, System, SystemPath, SystemPathBuf};
-use salsa::plumbing::ZalsaDatabase;
 use target_version::TargetVersion;
 
 use crate::logging::{setup_tracing, Verbosity};
@@ -183,10 +183,10 @@ fn run() -> anyhow::Result<ExitStatus> {
 
     let system = OsSystem::new(cwd.clone());
     let cli_configuration = args.to_configuration(&cwd);
-    let workspace_metadata = WorkspaceMetadata::discover(
+    let workspace_metadata = WorkspaceMetadata::from_path(
         system.current_directory(),
         &system,
-        Some(&cli_configuration),
+        Some(cli_configuration.clone()),
     )?;
 
     // TODO: Use the `program_settings` to compute the key for the database's persistent
@@ -318,9 +318,8 @@ impl MainLoop {
                 } => {
                     let has_diagnostics = !result.is_empty();
                     if check_revision == revision {
-                        #[allow(clippy::print_stdout)]
                         for diagnostic in result {
-                            println!("{}", diagnostic.display(db));
+                            tracing::error!("{}", diagnostic);
                         }
                     } else {
                         tracing::debug!(
@@ -379,10 +378,7 @@ impl MainLoopCancellationToken {
 #[derive(Debug)]
 enum MainLoopMessage {
     CheckWorkspace,
-    CheckCompleted {
-        result: Vec<Box<dyn Diagnostic>>,
-        revision: u64,
-    },
+    CheckCompleted { result: Vec<String>, revision: u64 },
     ApplyChanges(Vec<watch::ChangeEvent>),
     Exit,
 }

crates/red_knot/src/target_version.rs

@@ -4,8 +4,8 @@
 #[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
 pub enum TargetVersion {
     Py37,
-    Py38,
     #[default]
+    Py38,
     Py39,
     Py310,
     Py311,
@@ -46,17 +46,3 @@ impl From<TargetVersion> for red_knot_python_semantic::PythonVersion {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::target_version::TargetVersion;
-    use red_knot_python_semantic::PythonVersion;
-
-    #[test]
-    fn same_default_as_python_version() {
-        assert_eq!(
-            PythonVersion::from(TargetVersion::default()),
-            PythonVersion::default()
-        );
-    }
-}

crates/red_knot/tests/file_watching.rs

@@ -6,7 +6,7 @@ use std::time::Duration;
 use anyhow::{anyhow, Context};
 
 use red_knot_python_semantic::{resolve_module, ModuleName, Program, PythonVersion, SitePackages};
-use red_knot_workspace::db::{Db, RootDatabase};
+use red_knot_workspace::db::RootDatabase;
 use red_knot_workspace::watch;
 use red_knot_workspace::watch::{directory_watcher, WorkspaceWatcher};
 use red_knot_workspace::workspace::settings::{Configuration, SearchPathConfiguration};
@@ -14,7 +14,6 @@ use red_knot_workspace::workspace::WorkspaceMetadata;
 use ruff_db::files::{system_path_to_file, File, FileError};
 use ruff_db::source::source_text;
 use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
-use ruff_db::testing::setup_logging;
 use ruff_db::Upcast;
 
 struct TestCase {
@@ -70,6 +69,7 @@ impl TestCase {
         Some(all_events)
     }
 
+    #[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")
@@ -110,8 +110,8 @@ impl TestCase {
     ) -> anyhow::Result<()> {
         let program = Program::get(self.db());
 
-        let new_settings = configuration.to_settings(self.db.workspace().root(&self.db));
-        self.configuration.search_paths = configuration;
+        self.configuration.search_paths = configuration.clone();
+        let new_settings = configuration.into_settings(self.db.workspace().root(&self.db));
 
         program.update_search_paths(&mut self.db, &new_settings)?;
 
@@ -204,9 +204,7 @@ where
             .as_utf8_path()
             .canonicalize_utf8()
             .with_context(|| "Failed to canonicalize root path.")?,
-    )
-    .simplified()
-    .to_path_buf();
+    );
 
     let workspace_path = root_path.join("workspace");
 
@@ -243,7 +241,8 @@ where
         search_paths,
     };
 
-    let workspace = WorkspaceMetadata::discover(&workspace_path, &system, Some(&configuration))?;
+    let workspace =
+        WorkspaceMetadata::from_path(&workspace_path, &system, Some(configuration.clone()))?;
 
     let db = RootDatabase::new(workspace, system)?;
 
@@ -1312,138 +1311,3 @@ mod unix {
         Ok(())
     }
 }
-
-#[test]
-fn nested_packages_delete_root() -> anyhow::Result<()> {
-    let mut case = setup(|root: &SystemPath, workspace_root: &SystemPath| {
-        std::fs::write(
-            workspace_root.join("pyproject.toml").as_std_path(),
-            r#"
-            [project]
-            name = "inner"
-            "#,
-        )?;
-
-        std::fs::write(
-            root.join("pyproject.toml").as_std_path(),
-            r#"
-            [project]
-            name = "outer"
-            "#,
-        )?;
-
-        Ok(())
-    })?;
-
-    assert_eq!(
-        case.db().workspace().root(case.db()),
-        &*case.workspace_path("")
-    );
-
-    std::fs::remove_file(case.workspace_path("pyproject.toml").as_std_path())?;
-
-    let changes = case.stop_watch();
-
-    case.apply_changes(changes);
-
-    // It should now pick up the outer workspace.
-    assert_eq!(case.db().workspace().root(case.db()), case.root_path());
-
-    Ok(())
-}
-
-#[test]
-fn added_package() -> anyhow::Result<()> {
-    let _ = setup_logging();
-    let mut case = setup([
-        (
-            "pyproject.toml",
-            r#"
-            [project]
-            name = "inner"
-
-            [tool.knot.workspace]
-            members = ["packages/*"]
-            "#,
-        ),
-        (
-            "packages/a/pyproject.toml",
-            r#"
-            [project]
-            name = "a"
-            "#,
-        ),
-    ])?;
-
-    assert_eq!(case.db().workspace().packages(case.db()).len(), 2);
-
-    std::fs::create_dir(case.workspace_path("packages/b").as_std_path())
-        .context("failed to create folder for package 'b'")?;
-
-    // It seems that the file watcher won't pick up on file changes shortly after the folder
-    // was created... I suspect this is because most file watchers don't support recursive
-    // file watching. Instead, file-watching libraries manually implement recursive file watching
-    // by setting a watcher for each directory. But doing this obviously "lags" behind.
-    case.take_watch_changes();
-
-    std::fs::write(
-        case.workspace_path("packages/b/pyproject.toml")
-            .as_std_path(),
-        r#"
-            [project]
-            name = "b"
-            "#,
-    )
-    .context("failed to write pyproject.toml for package b")?;
-
-    let changes = case.stop_watch();
-
-    case.apply_changes(changes);
-
-    assert_eq!(case.db().workspace().packages(case.db()).len(), 3);
-
-    Ok(())
-}
-
-#[test]
-fn removed_package() -> anyhow::Result<()> {
-    let mut case = setup([
-        (
-            "pyproject.toml",
-            r#"
-            [project]
-            name = "inner"
-
-            [tool.knot.workspace]
-            members = ["packages/*"]
-            "#,
-        ),
-        (
-            "packages/a/pyproject.toml",
-            r#"
-            [project]
-            name = "a"
-            "#,
-        ),
-        (
-            "packages/b/pyproject.toml",
-            r#"
-            [project]
-            name = "b"
-            "#,
-        ),
-    ])?;
-
-    assert_eq!(case.db().workspace().packages(case.db()).len(), 3);
-
-    std::fs::remove_dir_all(case.workspace_path("packages/b").as_std_path())
-        .context("failed to remove package 'b'")?;
-
-    let changes = case.stop_watch();
-
-    case.apply_changes(changes);
-
-    assert_eq!(case.db().workspace().packages(case.db()).len(), 2);
-
-    Ok(())
-}

crates/red_knot_python_semantic/Cargo.toml

@@ -14,7 +14,6 @@ license = { workspace = true }
 ruff_db = { workspace = true }
 ruff_index = { workspace = true }
 ruff_python_ast = { workspace = true }
-ruff_python_parser = { workspace = true }
 ruff_python_stdlib = { workspace = true }
 ruff_source_file = { workspace = true }
 ruff_text_size = { workspace = true }
@@ -25,15 +24,13 @@ bitflags = { workspace = true }
 camino = { workspace = true }
 compact_str = { workspace = true }
 countme = { workspace = true }
-indexmap = { workspace = true }
-itertools = { workspace = true }
+itertools = { workspace = true}
 ordermap = { workspace = true }
 salsa = { workspace = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
 rustc-hash = { workspace = true }
 hashbrown = { workspace = true }
-serde = { workspace = true, optional = true }
 smallvec = { workspace = true }
 static_assertions = { workspace = true }
 test-case = { workspace = true }
@@ -46,9 +43,10 @@ red_knot_test = { workspace = true }
 red_knot_vendored = { workspace = true }
 
 anyhow = { workspace = true }
-dir-test = { workspace = true }
+dir-test = {workspace = true}
 insta = { workspace = true }
 tempfile = { workspace = true }
 
 [lints]
 workspace = true
+

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

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

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

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

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

@@ -1,191 +0,0 @@
-# String annotations
-
-## Simple
-
-```py
-def f() -> "int":
-    return 1
-
-reveal_type(f())  # revealed: int
-```
-
-## Nested
-
-```py
-def f() -> "'int'":
-    return 1
-
-reveal_type(f())  # revealed: int
-```
-
-## Type expression
-
-```py
-def f1() -> "int | str":
-    return 1
-
-def f2() -> "tuple[int, str]":
-    return 1
-
-reveal_type(f1())  # revealed: int | str
-reveal_type(f2())  # revealed: tuple[int, str]
-```
-
-## Partial
-
-```py
-def f() -> tuple[int, "str"]:
-    return 1
-
-reveal_type(f())  # revealed: tuple[int, str]
-```
-
-## Deferred
-
-```py
-def f() -> "Foo":
-    return Foo()
-
-class Foo:
-    pass
-
-reveal_type(f())  # revealed: Foo
-```
-
-## Deferred (undefined)
-
-```py
-# error: [unresolved-reference]
-def f() -> "Foo":
-    pass
-
-reveal_type(f())  # revealed: Unknown
-```
-
-## Partial deferred
-
-```py
-def f() -> int | "Foo":
-    return 1
-
-class Foo:
-    pass
-
-reveal_type(f())  # revealed: int | Foo
-```
-
-## `typing.Literal`
-
-```py
-from typing import Literal
-
-def f1() -> Literal["Foo", "Bar"]:
-    return "Foo"
-
-def f2() -> 'Literal["Foo", "Bar"]':
-    return "Foo"
-
-class Foo:
-    pass
-
-reveal_type(f1())  # revealed: Literal["Foo", "Bar"]
-reveal_type(f2())  # revealed: Literal["Foo", "Bar"]
-```
-
-## Various string kinds
-
-```py
-# error: [annotation-raw-string] "Type expressions cannot use raw string literal"
-def f1() -> r"int":
-    return 1
-
-# error: [annotation-f-string] "Type expressions cannot use f-strings"
-def f2() -> f"int":
-    return 1
-
-# error: [annotation-byte-string] "Type expressions cannot use bytes literal"
-def f3() -> b"int":
-    return 1
-
-def f4() -> "int":
-    return 1
-
-# error: [annotation-implicit-concat] "Type expressions cannot span multiple string literals"
-def f5() -> "in" "t":
-    return 1
-
-# error: [annotation-escape-character] "Type expressions cannot contain escape characters"
-def f6() -> "\N{LATIN SMALL LETTER I}nt":
-    return 1
-
-# error: [annotation-escape-character] "Type expressions cannot contain escape characters"
-def f7() -> "\x69nt":
-    return 1
-
-def f8() -> """int""":
-    return 1
-
-# error: [annotation-byte-string] "Type expressions cannot use bytes literal"
-def f9() -> "b'int'":
-    return 1
-
-reveal_type(f1())  # revealed: Unknown
-reveal_type(f2())  # revealed: Unknown
-reveal_type(f3())  # revealed: Unknown
-reveal_type(f4())  # revealed: int
-reveal_type(f5())  # revealed: Unknown
-reveal_type(f6())  # revealed: Unknown
-reveal_type(f7())  # revealed: Unknown
-reveal_type(f8())  # revealed: int
-reveal_type(f9())  # revealed: Unknown
-```
-
-## Various string kinds in `typing.Literal`
-
-```py
-from typing import Literal
-
-def f() -> Literal["a", r"b", b"c", "d" "e", "\N{LATIN SMALL LETTER F}", "\x67", """h"""]:
-    return "normal"
-
-reveal_type(f())  # revealed: Literal["a", "b", "de", "f", "g", "h"] | Literal[b"c"]
-```
-
-## Class variables
-
-```py
-MyType = int
-
-class Aliases:
-    MyType = str
-
-    forward: "MyType"
-    not_forward: MyType
-
-reveal_type(Aliases.forward)  # revealed: str
-reveal_type(Aliases.not_forward)  # revealed: str
-```
-
-## Annotated assignment
-
-```py
-a: "int" = 1
-b: "'int'" = 1
-c: "Foo"
-# error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `Foo`"
-d: "Foo" = 1
-
-class Foo:
-    pass
-
-c = Foo()
-
-reveal_type(a)  # revealed: Literal[1]
-reveal_type(b)  # revealed: Literal[1]
-reveal_type(c)  # revealed: Foo
-reveal_type(d)  # revealed: Foo
-```
-
-## Parameter
-
-TODO: Add tests once parameter inference is supported

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

@@ -110,29 +110,3 @@ c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = ((
 # error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `tuple[tuple[int, int], int]`"
 c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = "foo"
 ```
-
-## Future annotations are deferred
-
-```py
-from __future__ import annotations
-
-x: Foo
-
-class Foo:
-    pass
-
-x = Foo()
-reveal_type(x)  # revealed: Foo
-```
-
-## Annotations in stub files are deferred
-
-```pyi path=main.pyi
-x: Foo
-
-class Foo:
-    pass
-
-x = Foo()
-reveal_type(x)  # revealed: Foo
-```

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

@@ -85,7 +85,7 @@ f = Foo()
 # that `Foo.__iadd__` may be unbound as additional context.
 f += "Hello, world!"
 
-reveal_type(f)  # revealed: int | Unknown
+reveal_type(f)  # revealed: int
 ```
 
 ## Partially bound with `__add__`
@@ -104,7 +104,8 @@ class Foo:
 f = Foo()
 f += "Hello, world!"
 
-reveal_type(f)  # revealed: int | str
+# TODO(charlie): This should be `int | str`, since `__iadd__` may be unbound.
+reveal_type(f)  # revealed: int
 ```
 
 ## Partially bound target union
@@ -126,7 +127,8 @@ else:
     f = 42.0
 f += 12
 
-reveal_type(f)  # revealed: int | str | float
+# TODO(charlie): This should be `str | int | float`
+reveal_type(f)  # revealed: @Todo
 ```
 
 ## Target union
@@ -147,36 +149,6 @@ else:
     f = 42.0
 f += 12
 
-reveal_type(f)  # revealed: str | float
-```
-
-## Partially bound target union with `__add__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    def __add__(self, other: int) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-class Bar:
-    def __add__(self, other: int) -> bytes:
-        return b"Hello, world!"
-
-    def __iadd__(self, other: int) -> float:
-        return 42.0
-
-if flag:
-    f = Foo()
-else:
-    f = Bar()
-f += 12
-
-reveal_type(f)  # revealed: int | str | float
+# TODO(charlie): This should be `str | float`.
+reveal_type(f)  # revealed: @Todo
 ```

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

@@ -35,7 +35,6 @@ class C:
     if flag:
         x = 2
 
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C]` is possibly unbound"
 reveal_type(C.x)  # revealed: Literal[2]
 reveal_type(C.y)  # revealed: Literal[1]
 ```

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -9,128 +9,12 @@ def bool_instance() -> bool:
 flag = bool_instance()
 
 if flag:
-    class C1:
+    class C:
         x = 1
 
 else:
-    class C1:
+    class C:
         x = 2
 
-class C2:
-    if flag:
-        x = 3
-    else:
-        x = 4
-
-reveal_type(C1.x)  # revealed: Literal[1, 2]
-reveal_type(C2.x)  # revealed: Literal[3, 4]
-```
-
-## Inherited attributes
-
-```py
-class A:
-    X = "foo"
-
-class B(A): ...
-class C(B): ...
-
-reveal_type(C.X)  # revealed: Literal["foo"]
-```
-
-## Inherited attributes (multiple inheritance)
-
-```py
-class O: ...
-
-class F(O):
-    X = 56
-
-class E(O):
-    X = 42
-
-class D(O): ...
-class C(D, F): ...
-class B(E, D): ...
-class A(B, C): ...
-
-# revealed: tuple[Literal[A], Literal[B], Literal[E], Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(A.__mro__)
-
-# `E` is earlier in the MRO than `F`, so we should use the type of `E.X`
-reveal_type(A.X)  # revealed: Literal[42]
-```
-
-## Unions with possibly unbound paths
-
-### Definite boundness within a class
-
-In this example, the `x` attribute is not defined in the `C2` element of the union:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1:
-    x = 1
-
-class C2: ...
-
-class C3:
-    x = 3
-
-flag1 = bool_instance()
-flag2 = bool_instance()
-
-C = C1 if flag1 else C2 if flag2 else C3
-
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-reveal_type(C.x)  # revealed: Literal[1, 3]
-```
-
-### Possibly-unbound within a class
-
-We raise the same diagnostic if the attribute is possibly-unbound in at least one element of the
-union:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1:
-    x = 1
-
-class C2:
-    if bool_instance():
-        x = 2
-
-class C3:
-    x = 3
-
-flag1 = bool_instance()
-flag2 = bool_instance()
-
-C = C1 if flag1 else C2 if flag2 else C3
-
-# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-reveal_type(C.x)  # revealed: Literal[1, 2, 3]
-```
-
-## Unions with all paths unbound
-
-If the symbol is unbound in all elements of the union, we detect that:
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class C1: ...
-class C2: ...
-
-flag = bool_instance()
-
-C = C1 if flag else C2
-
-# error: [unresolved-attribute] "Type `Literal[C1, C2]` has no attribute `x`"
-reveal_type(C.x)  # revealed: Unknown
+reveal_type(C.x)  # revealed: Literal[1, 2]
 ```

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

@@ -202,7 +202,11 @@ reveal_type(A() + B())  # revealed: MyString
 # N.B. Still a subtype of `A`, even though `A` does not appear directly in the class's `__bases__`
 class C(B): ...
 
-reveal_type(A() + C())  # revealed: MyString
+# TODO: we currently only understand direct subclasses as subtypes of the superclass.
+# We need to iterate through the full MRO rather than just the class's bases;
+# if we do, we'll understand `C` as a subtype of `A`, and correctly understand this as being
+# `MyString` rather than `str`
+reveal_type(A() + C())  # revealed: str
 ```
 
 ## Reflected precedence 2

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

@@ -18,58 +18,3 @@ class Unit: ...
 b = Unit()(3.0)  # error: "Object of type `Unit` is not callable"
 reveal_type(b)  # revealed: Unknown
 ```
-
-## Possibly unbound `__call__` method
-
-```py
-def flag() -> bool: ...
-
-class PossiblyNotCallable:
-    if flag():
-        def __call__(self) -> int: ...
-
-a = PossiblyNotCallable()
-result = a()  # error: "Object of type `PossiblyNotCallable` is not callable (possibly unbound `__call__` method)"
-reveal_type(result)  # revealed: int
-```
-
-## Possibly unbound callable
-
-```py
-def flag() -> bool: ...
-
-if flag():
-    class PossiblyUnbound:
-        def __call__(self) -> int: ...
-
-# error: [possibly-unresolved-reference]
-a = PossiblyUnbound()
-reveal_type(a())  # revealed: int
-```
-
-## Non-callable `__call__`
-
-```py
-class NonCallable:
-    __call__ = 1
-
-a = NonCallable()
-# error: "Object of type `NonCallable` is not callable"
-reveal_type(a())  # revealed: Unknown
-```
-
-## Possibly non-callable `__call__`
-
-```py
-def flag() -> bool: ...
-
-class NonCallable:
-    if flag():
-        __call__ = 1
-    else:
-        def __call__(self) -> int: ...
-
-a = NonCallable()
-# error: "Object of type `Literal[1] | Literal[__call__]` is not callable (due to union element `Literal[1]`)"
-reveal_type(a())  # revealed: Unknown | int
-```

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

@@ -19,15 +19,6 @@ async def get_int_async() -> int:
 reveal_type(get_int_async())  # revealed: @Todo
 ```
 
-## Generic
-
-```py
-def get_int[T]() -> int:
-    return 42
-
-reveal_type(get_int())  # revealed: int
-```
-
 ## Decorated
 
 ```py
@@ -53,16 +44,3 @@ reveal_type(bar())  # revealed: @Todo
 nonsense = 123
 x = nonsense()  # error: "Object of type `Literal[123]` is not callable"
 ```
-
-## Potentially unbound function
-
-```py
-def flag() -> bool: ...
-
-if flag():
-    def foo() -> int:
-        return 42
-
-# error: [possibly-unresolved-reference]
-reveal_type(foo())  # revealed: int
-```

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

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

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

@@ -93,11 +93,13 @@ class AlwaysFalse:
     def __contains__(self, item: int) -> Literal[""]:
         return ""
 
-reveal_type(42 in AlwaysTrue())  # revealed: Literal[True]
-reveal_type(42 not in AlwaysTrue())  # revealed: Literal[False]
+# TODO: it should be Literal[True] and Literal[False]
+reveal_type(42 in AlwaysTrue())  # revealed: @Todo
+reveal_type(42 not in AlwaysTrue())  # revealed: @Todo
 
-reveal_type(42 in AlwaysFalse())  # revealed: Literal[False]
-reveal_type(42 not in AlwaysFalse())  # revealed: Literal[True]
+# TODO: it should be Literal[False] and Literal[True]
+reveal_type(42 in AlwaysFalse())  # revealed: @Todo
+reveal_type(42 not in AlwaysFalse())  # revealed: @Todo
 ```
 
 ## No Fallback for `__contains__`

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

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

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

@@ -41,10 +41,11 @@ except EXCEPTIONS as f:
 ## Dynamic exception types
 
 ```py
+# TODO: we should not emit these `call-possibly-unbound-method` errors for `tuple.__class_getitem__`
 def foo(
     x: type[AttributeError],
-    y: tuple[type[OSError], type[RuntimeError]],
-    z: tuple[type[BaseException], ...],
+    y: tuple[type[OSError], type[RuntimeError]],  # error: [call-possibly-unbound-method]
+    z: tuple[type[BaseException], ...],  # error: [call-possibly-unbound-method]
 ):
     try:
         help()

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

@@ -1,13 +0,0 @@
-# Exception Handling
-
-## Invalid syntax
-
-```py
-from typing_extensions import reveal_type
-
-try:
-    print
-except as e:  # error: [invalid-syntax]
-    reveal_type(e)  # revealed: Unknown
-
-```

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

@@ -1,28 +0,0 @@
-# Attribute access
-
-## Boundness
-
-```py
-def flag() -> bool: ...
-
-class A:
-    always_bound = 1
-
-    if flag():
-        union = 1
-    else:
-        union = "abc"
-
-    if flag():
-        possibly_unbound = "abc"
-
-reveal_type(A.always_bound)  # revealed: Literal[1]
-
-reveal_type(A.union)  # revealed: Literal[1] | Literal["abc"]
-
-# error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
-reveal_type(A.possibly_unbound)  # revealed: Literal["abc"]
-
-# error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
-reveal_type(A.non_existent)  # revealed: Unknown
-```

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

@@ -1,24 +0,0 @@
-# If expression
-
-## Union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-reveal_type(1 if bool_instance() else 2)  # revealed: Literal[1, 2]
-```
-
-## Statically known branches
-
-```py
-reveal_type(1 if True else 2)  # revealed: Literal[1]
-reveal_type(1 if "not empty" else 2)  # revealed: Literal[1]
-reveal_type(1 if (1,) else 2)  # revealed: Literal[1]
-reveal_type(1 if 1 else 2)  # revealed: Literal[1]
-
-reveal_type(1 if False else 2)  # revealed: Literal[2]
-reveal_type(1 if None else 2)  # revealed: Literal[2]
-reveal_type(1 if "" else 2)  # revealed: Literal[2]
-reveal_type(1 if 0 else 2)  # revealed: Literal[2]
-```

crates/red_knot_python_semantic/resources/mdtest/generics.md

@@ -6,9 +6,13 @@ Basic PEP 695 generics
 
 ```py
 class MyBox[T]:
+    # TODO: `T` is defined here
+    # error: [unresolved-reference] "Name `T` used when not defined"
     data: T
     box_model_number = 695
 
+    # TODO: `T` is defined here
+    # error: [unresolved-reference] "Name `T` used when not defined"
     def __init__(self, data: T):
         self.data = data
 
@@ -27,12 +31,17 @@ reveal_type(MyBox.box_model_number)  # revealed: Literal[695]
 
 ```py
 class MyBox[T]:
+    # TODO: `T` is defined here
+    # error: [unresolved-reference] "Name `T` used when not defined"
     data: T
 
+    # TODO: `T` is defined here
+    # error: [unresolved-reference] "Name `T` used when not defined"
     def __init__(self, data: T):
         self.data = data
 
-# TODO not error on the subscripting
+# TODO not error on the subscripting or the use of type param
+# error: [unresolved-reference] "Name `T` used when not defined"
 # error: [non-subscriptable]
 class MySecureBox[T](MyBox[T]): ...
 
@@ -57,55 +66,3 @@ class S[T](Seq[S]): ...  # error: [non-subscriptable]
 
 reveal_type(S)  # revealed: Literal[S]
 ```
-
-## Type params
-
-A PEP695 type variable defines a value of type `typing.TypeVar` with attributes `__name__`,
-`__bounds__`, `__constraints__`, and `__default__` (the latter three all lazily evaluated):
-
-```py
-def f[T, U: A, V: (A, B), W = A, X: A = A1]():
-    reveal_type(T)  # revealed: T
-    reveal_type(T.__name__)  # revealed: Literal["T"]
-    reveal_type(T.__bound__)  # revealed: None
-    reveal_type(T.__constraints__)  # revealed: tuple[()]
-    reveal_type(T.__default__)  # revealed: NoDefault
-
-    reveal_type(U)  # revealed: U
-    reveal_type(U.__name__)  # revealed: Literal["U"]
-    reveal_type(U.__bound__)  # revealed: type[A]
-    reveal_type(U.__constraints__)  # revealed: tuple[()]
-    reveal_type(U.__default__)  # revealed: NoDefault
-
-    reveal_type(V)  # revealed: V
-    reveal_type(V.__name__)  # revealed: Literal["V"]
-    reveal_type(V.__bound__)  # revealed: None
-    reveal_type(V.__constraints__)  # revealed: tuple[type[A], type[B]]
-    reveal_type(V.__default__)  # revealed: NoDefault
-
-    reveal_type(W)  # revealed: W
-    reveal_type(W.__name__)  # revealed: Literal["W"]
-    reveal_type(W.__bound__)  # revealed: None
-    reveal_type(W.__constraints__)  # revealed: tuple[()]
-    reveal_type(W.__default__)  # revealed: type[A]
-
-    reveal_type(X)  # revealed: X
-    reveal_type(X.__name__)  # revealed: Literal["X"]
-    reveal_type(X.__bound__)  # revealed: type[A]
-    reveal_type(X.__constraints__)  # revealed: tuple[()]
-    reveal_type(X.__default__)  # revealed: type[A1]
-
-class A: ...
-class B: ...
-class A1(A): ...
-```
-
-## Minimum two constraints
-
-A typevar with less than two constraints emits a diagnostic and is treated as unconstrained:
-
-```py
-# error: [invalid-typevar-constraints] "TypeVar must have at least two constrained types"
-def f[T: (int,)]():
-    reveal_type(T.__constraints__)  # revealed: tuple[()]
-```

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

@@ -21,7 +21,6 @@ reveal_type(y)
 ```
 
 ```py
-# error: [possibly-unbound-import] "Member `y` of module `maybe_unbound` is possibly unbound"
 from maybe_unbound import x, y
 
 reveal_type(x)  # revealed: Literal[3]
@@ -51,7 +50,6 @@ reveal_type(y)
 Importing an annotated name prefers the declared type over the inferred type:
 
 ```py
-# error: [possibly-unbound-import] "Member `y` of module `maybe_unbound_annotated` is possibly unbound"
 from maybe_unbound_annotated import x, y
 
 reveal_type(x)  # revealed: Literal[3]

crates/red_knot_python_semantic/resources/mdtest/literal/literal.md

@@ -1,93 +0,0 @@
-# Literal
-
-<https://typing.readthedocs.io/en/latest/spec/literal.html#literals>
-
-## Parameterization
-
-```py
-from typing import Literal
-from enum import Enum
-
-mode: Literal["w", "r"]
-mode2: Literal["w"] | Literal["r"]
-union_var: Literal[Literal[Literal[1, 2, 3], "foo"], 5, None]
-a1: Literal[26]
-a2: Literal[0x1A]
-a3: Literal[-4]
-a4: Literal["hello world"]
-a5: Literal[b"hello world"]
-a6: Literal[True]
-a7: Literal[None]
-a8: Literal[Literal[1]]
-a9: Literal[Literal["w"], Literal["r"], Literal[Literal["w+"]]]
-
-class Color(Enum):
-    RED = 0
-    GREEN = 1
-    BLUE = 2
-
-b1: Literal[Color.RED]
-
-def f():
-    reveal_type(mode)  # revealed: Literal["w", "r"]
-    reveal_type(mode2)  # revealed: Literal["w", "r"]
-    # TODO: should be revealed: Literal[1, 2, 3, "foo", 5] | None
-    reveal_type(union_var)  # revealed: Literal[1, 2, 3, 5] | Literal["foo"] | None
-    reveal_type(a1)  # revealed: Literal[26]
-    reveal_type(a2)  # revealed: Literal[26]
-    reveal_type(a3)  # revealed: Literal[-4]
-    reveal_type(a4)  # revealed: Literal["hello world"]
-    reveal_type(a5)  # revealed: Literal[b"hello world"]
-    reveal_type(a6)  # revealed: Literal[True]
-    reveal_type(a7)  # revealed: None
-    reveal_type(a8)  # revealed: Literal[1]
-    reveal_type(a9)  # revealed: Literal["w", "r", "w+"]
-    # TODO: This should be Color.RED
-    reveal_type(b1)  # revealed: Literal[0]
-
-# error: [invalid-literal-parameter]
-invalid1: Literal[3 + 4]
-# error: [invalid-literal-parameter]
-invalid2: Literal[4 + 3j]
-# error: [invalid-literal-parameter]
-invalid3: Literal[(3, 4)]
-
-hello = "hello"
-invalid4: Literal[
-    1 + 2,  # error: [invalid-literal-parameter]
-    "foo",
-    hello,  # error: [invalid-literal-parameter]
-    (1, 2, 3),  # error: [invalid-literal-parameter]
-]
-```
-
-## Detecting Literal outside typing and typing_extensions
-
-Only Literal that is defined in typing and typing_extension modules is detected as the special
-Literal.
-
-```pyi path=other.pyi
-from typing import _SpecialForm
-
-Literal: _SpecialForm
-```
-
-```py
-from other import Literal
-
-a1: Literal[26]
-
-def f():
-    reveal_type(a1)  # revealed: @Todo
-```
-
-## Detecting typing_extensions.Literal
-
-```py
-from typing_extensions import Literal
-
-a1: Literal[26]
-
-def f():
-    reveal_type(a1)  # revealed: Literal[26]
-```

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

@@ -238,7 +238,7 @@ class Test:
 def coinflip() -> bool:
     return True
 
-# error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
+# TODO: we should emit a diagnostic here (it might not be iterable)
 for x in Test() if coinflip() else 42:
     reveal_type(x)  # revealed: int
 ```

crates/red_knot_python_semantic/resources/mdtest/metaclass.md

@@ -1,196 +0,0 @@
-## Default
-
-```py
-class M(type): ...
-
-reveal_type(M.__class__)  # revealed: Literal[type]
-```
-
-## `object`
-
-```py
-reveal_type(object.__class__)  # revealed: Literal[type]
-```
-
-## `type`
-
-```py
-reveal_type(type.__class__)  # revealed: Literal[type]
-```
-
-## Basic
-
-```py
-class M(type): ...
-class B(metaclass=M): ...
-
-reveal_type(B.__class__)  # revealed: Literal[M]
-```
-
-## Invalid metaclass
-
-A class which doesn't inherit `type` (and/or doesn't implement a custom `__new__` accepting the same
-arguments as `type.__new__`) isn't a valid metaclass.
-
-```py
-class M: ...
-class A(metaclass=M): ...
-
-# TODO: emit a diagnostic for the invalid metaclass
-reveal_type(A.__class__)  # revealed: Literal[M]
-```
-
-## Linear inheritance
-
-If a class is a subclass of a class with a custom metaclass, then the subclass will also have that
-metaclass.
-
-```py
-class M(type): ...
-class A(metaclass=M): ...
-class B(A): ...
-
-reveal_type(B.__class__)  # revealed: Literal[M]
-```
-
-## Conflict (1)
-
-The metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its
-bases. ("Strict subclass" is a synonym for "proper subclass"; a non-strict subclass can be a
-subclass or the class itself.)
-
-```py
-class M1(type): ...
-class M2(type): ...
-class A(metaclass=M1): ...
-class B(metaclass=M2): ...
-
-# error: [conflicting-metaclass] "The metaclass of a derived class (`C`) must be a subclass of the metaclasses of all its bases, but `M1` (metaclass of base class `A`) and `M2` (metaclass of base class `B`) have no subclass relationship"
-class C(A, B): ...
-
-reveal_type(C.__class__)  # revealed: Unknown
-```
-
-## Conflict (2)
-
-The metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its
-bases. ("Strict subclass" is a synonym for "proper subclass"; a non-strict subclass can be a
-subclass or the class itself.)
-
-```py
-class M1(type): ...
-class M2(type): ...
-class A(metaclass=M1): ...
-
-# error: [conflicting-metaclass] "The metaclass of a derived class (`B`) must be a subclass of the metaclasses of all its bases, but `M2` (metaclass of `B`) and `M1` (metaclass of base class `A`) have no subclass relationship"
-class B(A, metaclass=M2): ...
-
-reveal_type(B.__class__)  # revealed: Unknown
-```
-
-## Common metaclass
-
-A class has two explicit bases, both of which have the same metaclass.
-
-```py
-class M(type): ...
-class A(metaclass=M): ...
-class B(metaclass=M): ...
-class C(A, B): ...
-
-reveal_type(C.__class__)  # revealed: Literal[M]
-```
-
-## Metaclass metaclass
-
-A class has an explicit base with a custom metaclass. That metaclass itself has a custom metaclass.
-
-```py
-class M1(type): ...
-class M2(type, metaclass=M1): ...
-class M3(M2): ...
-class A(metaclass=M3): ...
-class B(A): ...
-
-reveal_type(A.__class__)  # revealed: Literal[M3]
-```
-
-## Diamond inheritance
-
-```py
-class M(type): ...
-class M1(M): ...
-class M2(M): ...
-class M12(M1, M2): ...
-class A(metaclass=M1): ...
-class B(metaclass=M2): ...
-class C(metaclass=M12): ...
-
-# error: [conflicting-metaclass] "The metaclass of a derived class (`D`) must be a subclass of the metaclasses of all its bases, but `M1` (metaclass of base class `A`) and `M2` (metaclass of base class `B`) have no subclass relationship"
-class D(A, B, C): ...
-
-reveal_type(D.__class__)  # revealed: Unknown
-```
-
-## Unknown
-
-```py
-from nonexistent_module import UnknownClass  # error: [unresolved-import]
-
-class C(UnknownClass): ...
-
-# TODO: should be `type[type] & Unknown`
-reveal_type(C.__class__)  # revealed: Literal[type]
-
-class M(type): ...
-class A(metaclass=M): ...
-class B(A, UnknownClass): ...
-
-# TODO: should be `type[M] & Unknown`
-reveal_type(B.__class__)  # revealed: Literal[M]
-```
-
-## Duplicate
-
-```py
-class M(type): ...
-class A(metaclass=M): ...
-class B(A, A): ...  # error: [duplicate-base] "Duplicate base class `A`"
-
-reveal_type(B.__class__)  # revealed: Literal[M]
-```
-
-## Non-class
-
-When a class has an explicit `metaclass` that is not a class, but is a callable that accepts
-`type.__new__` arguments, we should return the meta type of its return type.
-
-```py
-def f(*args, **kwargs) -> int: ...
-
-class A(metaclass=f): ...
-
-# TODO should be `type[int]`
-reveal_type(A.__class__)  # revealed: @Todo
-```
-
-## Cyclic
-
-Retrieving the metaclass of a cyclically defined class should not cause an infinite loop.
-
-```py path=a.pyi
-class A(B): ...  # error: [cyclic-class-def]
-class B(C): ...  # error: [cyclic-class-def]
-class C(A): ...  # error: [cyclic-class-def]
-
-reveal_type(A.__class__)  # revealed: Unknown
-```
-
-## PEP 695 generic
-
-```py
-class M(type): ...
-class A[T: str](metaclass=M): ...
-
-reveal_type(A.__class__)  # revealed: Literal[M]
-```

crates/red_knot_python_semantic/resources/mdtest/mro.md

@@ -1,409 +0,0 @@
-# Method Resolution Order tests
-
-Tests that assert that we can infer the correct type for a class's `__mro__` attribute.
-
-This attribute is rarely accessed directly at runtime. However, it's extremely important for *us* to
-know the precise possible values of a class's Method Resolution Order, or we won't be able to infer
-the correct type of attributes accessed from instances.
-
-For documentation on method resolution orders, see:
-
-- <https://docs.python.org/3/glossary.html#term-method-resolution-order>
-- <https://docs.python.org/3/howto/mro.html#python-2-3-mro>
-
-## No bases
-
-```py
-class C: ...
-
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[object]]
-```
-
-## The special case: `object` itself
-
-```py
-reveal_type(object.__mro__)  # revealed: tuple[Literal[object]]
-```
-
-## Explicit inheritance from `object`
-
-```py
-class C(object): ...
-
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[object]]
-```
-
-## Explicit inheritance from non-`object` single base
-
-```py
-class A: ...
-class B(A): ...
-
-reveal_type(B.__mro__)  # revealed: tuple[Literal[B], Literal[A], Literal[object]]
-```
-
-## Linearization of multiple bases
-
-```py
-class A: ...
-class B: ...
-class C(A, B): ...
-
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[A], Literal[B], Literal[object]]
-```
-
-## Complex diamond inheritance (1)
-
-This is "ex_2" from <https://docs.python.org/3/howto/mro.html#the-end>
-
-```py
-class O: ...
-class X(O): ...
-class Y(O): ...
-class A(X, Y): ...
-class B(Y, X): ...
-
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Literal[X], Literal[Y], Literal[O], Literal[object]]
-reveal_type(B.__mro__)  # revealed: tuple[Literal[B], Literal[Y], Literal[X], Literal[O], Literal[object]]
-```
-
-## Complex diamond inheritance (2)
-
-This is "ex_5" from <https://docs.python.org/3/howto/mro.html#the-end>
-
-```py
-class O: ...
-class F(O): ...
-class E(O): ...
-class D(O): ...
-class C(D, F): ...
-class B(D, E): ...
-class A(B, C): ...
-
-# revealed: tuple[Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(C.__mro__)
-# revealed: tuple[Literal[B], Literal[D], Literal[E], Literal[O], Literal[object]]
-reveal_type(B.__mro__)
-# revealed: tuple[Literal[A], Literal[B], Literal[C], Literal[D], Literal[E], Literal[F], Literal[O], Literal[object]]
-reveal_type(A.__mro__)
-```
-
-## Complex diamond inheritance (3)
-
-This is "ex_6" from <https://docs.python.org/3/howto/mro.html#the-end>
-
-```py
-class O: ...
-class F(O): ...
-class E(O): ...
-class D(O): ...
-class C(D, F): ...
-class B(E, D): ...
-class A(B, C): ...
-
-# revealed: tuple[Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(C.__mro__)
-# revealed: tuple[Literal[B], Literal[E], Literal[D], Literal[O], Literal[object]]
-reveal_type(B.__mro__)
-# revealed: tuple[Literal[A], Literal[B], Literal[E], Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(A.__mro__)
-```
-
-## Complex diamond inheritance (4)
-
-This is "ex_9" from <https://docs.python.org/3/howto/mro.html#the-end>
-
-```py
-class O: ...
-class A(O): ...
-class B(O): ...
-class C(O): ...
-class D(O): ...
-class E(O): ...
-class K1(A, B, C): ...
-class K2(D, B, E): ...
-class K3(D, A): ...
-class Z(K1, K2, K3): ...
-
-# revealed: tuple[Literal[K1], Literal[A], Literal[B], Literal[C], Literal[O], Literal[object]]
-reveal_type(K1.__mro__)
-# revealed: tuple[Literal[K2], Literal[D], Literal[B], Literal[E], Literal[O], Literal[object]]
-reveal_type(K2.__mro__)
-# revealed: tuple[Literal[K3], Literal[D], Literal[A], Literal[O], Literal[object]]
-reveal_type(K3.__mro__)
-# revealed: tuple[Literal[Z], Literal[K1], Literal[K2], Literal[K3], Literal[D], Literal[A], Literal[B], Literal[C], Literal[E], Literal[O], Literal[object]]
-reveal_type(Z.__mro__)
-```
-
-## Inheritance from `Unknown`
-
-```py
-from does_not_exist import DoesNotExist  # error: [unresolved-import]
-
-class A(DoesNotExist): ...
-class B: ...
-class C: ...
-class D(A, B, C): ...
-class E(B, C): ...
-class F(E, A): ...
-
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Unknown, Literal[object]]
-reveal_type(D.__mro__)  # revealed: tuple[Literal[D], Literal[A], Unknown, Literal[B], Literal[C], Literal[object]]
-reveal_type(E.__mro__)  # revealed: tuple[Literal[E], Literal[B], Literal[C], Literal[object]]
-reveal_type(F.__mro__)  # revealed: tuple[Literal[F], Literal[E], Literal[B], Literal[C], Literal[A], Unknown, Literal[object]]
-```
-
-## `__bases__` lists that cause errors at runtime
-
-If the class's `__bases__` cause an exception to be raised at runtime and therefore the class
-creation to fail, we infer the class's `__mro__` as being `[<class>, Unknown, object]`:
-
-```py
-# error: [inconsistent-mro] "Cannot create a consistent method resolution order (MRO) for class `Foo` with bases list `[<class 'object'>, <class 'int'>]`"
-class Foo(object, int): ...
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-
-class Bar(Foo): ...
-
-reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Literal[Foo], Unknown, Literal[object]]
-
-# This is the `TypeError` at the bottom of "ex_2"
-# in the examples at <https://docs.python.org/3/howto/mro.html#the-end>
-class O: ...
-class X(O): ...
-class Y(O): ...
-class A(X, Y): ...
-class B(Y, X): ...
-
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Literal[X], Literal[Y], Literal[O], Literal[object]]
-reveal_type(B.__mro__)  # revealed: tuple[Literal[B], Literal[Y], Literal[X], Literal[O], Literal[object]]
-
-# error: [inconsistent-mro] "Cannot create a consistent method resolution order (MRO) for class `Z` with bases list `[<class 'A'>, <class 'B'>]`"
-class Z(A, B): ...
-
-reveal_type(Z.__mro__)  # revealed: tuple[Literal[Z], Unknown, Literal[object]]
-
-class AA(Z): ...
-
-reveal_type(AA.__mro__)  # revealed: tuple[Literal[AA], Literal[Z], Unknown, Literal[object]]
-```
-
-## `__bases__` includes a `Union`
-
-We don't support union types in a class's bases; a base must resolve to a single `ClassLiteralType`.
-If we find a union type in a class's bases, we infer the class's `__mro__` as being
-`[<class>, Unknown, object]`, the same as for MROs that cause errors at runtime.
-
-```py
-def returns_bool() -> bool:
-    return True
-
-class A: ...
-class B: ...
-
-if returns_bool():
-    x = A
-else:
-    x = B
-
-reveal_type(x)  # revealed: Literal[A, B]
-
-# error: 11 [invalid-base] "Invalid class base with type `Literal[A, B]` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class Foo(x): ...
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-```
-
-## `__bases__` includes multiple `Union`s
-
-```py
-def returns_bool() -> bool:
-    return True
-
-class A: ...
-class B: ...
-class C: ...
-class D: ...
-
-if returns_bool():
-    x = A
-else:
-    x = B
-
-if returns_bool():
-    y = C
-else:
-    y = D
-
-reveal_type(x)  # revealed: Literal[A, B]
-reveal_type(y)  # revealed: Literal[C, D]
-
-# error: 11 [invalid-base] "Invalid class base with type `Literal[A, B]` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-# error: 14 [invalid-base] "Invalid class base with type `Literal[C, D]` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class Foo(x, y): ...
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-```
-
-## `__bases__` lists that cause errors... now with `Union`s
-
-```py
-def returns_bool() -> bool:
-    return True
-
-class O: ...
-class X(O): ...
-class Y(O): ...
-
-if bool():
-    foo = Y
-else:
-    foo = object
-
-# error: 21 [invalid-base] "Invalid class base with type `Literal[Y, object]` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class PossibleError(foo, X): ...
-
-reveal_type(PossibleError.__mro__)  # revealed: tuple[Literal[PossibleError], Unknown, Literal[object]]
-
-class A(X, Y): ...
-
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Literal[X], Literal[Y], Literal[O], Literal[object]]
-
-if returns_bool():
-    class B(X, Y): ...
-
-else:
-    class B(Y, X): ...
-
-# revealed: tuple[Literal[B], Literal[X], Literal[Y], Literal[O], Literal[object]] | tuple[Literal[B], Literal[Y], Literal[X], Literal[O], Literal[object]]
-reveal_type(B.__mro__)
-
-# error: 12 [invalid-base] "Invalid class base with type `Literal[B, B]` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class Z(A, B): ...
-
-reveal_type(Z.__mro__)  # revealed: tuple[Literal[Z], Unknown, Literal[object]]
-```
-
-## `__bases__` lists with duplicate bases
-
-```py
-class Foo(str, str): ...  # error: 16 [duplicate-base] "Duplicate base class `str`"
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-
-class Spam: ...
-class Eggs: ...
-class Ham(
-    Spam,
-    Eggs,
-    Spam,  # error: [duplicate-base] "Duplicate base class `Spam`"
-    Eggs,  # error: [duplicate-base] "Duplicate base class `Eggs`"
-): ...
-
-reveal_type(Ham.__mro__)  # revealed: tuple[Literal[Ham], Unknown, Literal[object]]
-
-class Mushrooms: ...
-class Omelette(Spam, Eggs, Mushrooms, Mushrooms): ...  # error: [duplicate-base]
-
-reveal_type(Omelette.__mro__)  # revealed: tuple[Literal[Omelette], Unknown, Literal[object]]
-```
-
-## `__bases__` lists with duplicate `Unknown` bases
-
-```py
-# error: [unresolved-import]
-# error: [unresolved-import]
-from does_not_exist import unknown_object_1, unknown_object_2
-
-reveal_type(unknown_object_1)  # revealed: Unknown
-reveal_type(unknown_object_2)  # revealed: Unknown
-
-# We *should* emit an error here to warn the user that we have no idea
-# what the MRO of this class should really be.
-# However, we don't complain about "duplicate base classes" here,
-# even though two classes are both inferred as being `Unknown`.
-#
-# (TODO: should we revisit this? Does it violate the gradual guarantee?
-# Should we just silently infer `[Foo, Unknown, object]` as the MRO here
-# without emitting any error at all? Not sure...)
-#
-# error: [inconsistent-mro] "Cannot create a consistent method resolution order (MRO) for class `Foo` with bases list `[Unknown, Unknown]`"
-class Foo(unknown_object_1, unknown_object_2): ...
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-```
-
-## Unrelated objects inferred as `Any`/`Unknown` do not have special `__mro__` attributes
-
-```py
-from does_not_exist import unknown_object  # error: [unresolved-import]
-
-reveal_type(unknown_object)  # revealed: Unknown
-reveal_type(unknown_object.__mro__)  # revealed: Unknown
-```
-
-## Classes that inherit from themselves
-
-These are invalid, but we need to be able to handle them gracefully without panicking.
-
-```py path=a.pyi
-class Foo(Foo): ...  # error: [cyclic-class-def]
-
-reveal_type(Foo)  # revealed: Literal[Foo]
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-
-class Bar: ...
-class Baz: ...
-class Boz(Bar, Baz, Boz): ...  # error: [cyclic-class-def]
-
-reveal_type(Boz)  # revealed: Literal[Boz]
-reveal_type(Boz.__mro__)  # revealed: tuple[Literal[Boz], Unknown, Literal[object]]
-```
-
-## Classes with indirect cycles in their MROs
-
-These are similarly unlikely, but we still shouldn't crash:
-
-```py path=a.pyi
-class Foo(Bar): ...  # error: [cyclic-class-def]
-class Bar(Baz): ...  # error: [cyclic-class-def]
-class Baz(Foo): ...  # error: [cyclic-class-def]
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
-reveal_type(Baz.__mro__)  # revealed: tuple[Literal[Baz], Unknown, Literal[object]]
-```
-
-## Classes with cycles in their MROs, and multiple inheritance
-
-```py path=a.pyi
-class Spam: ...
-class Foo(Bar): ...  # error: [cyclic-class-def]
-class Bar(Baz): ...  # error: [cyclic-class-def]
-class Baz(Foo, Spam): ...  # error: [cyclic-class-def]
-
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
-reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
-reveal_type(Baz.__mro__)  # revealed: tuple[Literal[Baz], Unknown, Literal[object]]
-```
-
-## Classes with cycles in their MRO, and a sub-graph
-
-```py path=a.pyi
-class FooCycle(BarCycle): ...  # error: [cyclic-class-def]
-class Foo: ...
-class BarCycle(FooCycle): ...  # error: [cyclic-class-def]
-class Bar(Foo): ...
-
-# TODO: can we avoid emitting the errors for these?
-# The classes have cyclic superclasses,
-# but are not themselves cyclic...
-class Baz(Bar, BarCycle): ...  # error: [cyclic-class-def]
-class Spam(Baz): ...  # error: [cyclic-class-def]
-
-reveal_type(FooCycle.__mro__)  # revealed: tuple[Literal[FooCycle], Unknown, Literal[object]]
-reveal_type(BarCycle.__mro__)  # revealed: tuple[Literal[BarCycle], Unknown, Literal[object]]
-reveal_type(Baz.__mro__)  # revealed: tuple[Literal[Baz], Unknown, Literal[object]]
-reveal_type(Spam.__mro__)  # revealed: tuple[Literal[Spam], Unknown, Literal[object]]
-```

crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/boolean.md

@@ -1,282 +0,0 @@
-# Narrowing for conditionals with boolean expressions
-
-## Narrowing in `and` conditional
-
-```py
-class A: ...
-class B: ...
-
-def instance() -> A | B:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) and isinstance(x, B):
-    reveal_type(x)  # revealed:  A & B
-else:
-    reveal_type(x)  # revealed:  B & ~A | A & ~B
-```
-
-## Arms might not add narrowing constraints
-
-```py
-class A: ...
-class B: ...
-
-def bool_instance() -> bool:
-    return True
-
-def instance() -> A | B:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) and bool_instance():
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: A | B
-
-if bool_instance() and isinstance(x, A):
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: A | B
-
-reveal_type(x)  # revealed: A | B
-```
-
-## Statically known arms
-
-```py
-class A: ...
-class B: ...
-
-def instance() -> A | B:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) and True:
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: B & ~A
-
-if True and isinstance(x, A):
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: B & ~A
-
-if False and isinstance(x, A):
-    # TODO: should emit an `unreachable code` diagnostic
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: A | B
-
-if False or isinstance(x, A):
-    reveal_type(x)  # revealed: A
-else:
-    reveal_type(x)  # revealed: B & ~A
-
-if True or isinstance(x, A):
-    reveal_type(x)  # revealed: A | B
-else:
-    # TODO: should emit an `unreachable code` diagnostic
-    reveal_type(x)  # revealed: B & ~A
-
-reveal_type(x)  # revealed: A | B
-```
-
-## The type of multiple symbols can be narrowed down
-
-```py
-class A: ...
-class B: ...
-
-def instance() -> A | B:
-    return A()
-
-x = instance()
-y = instance()
-
-if isinstance(x, A) and isinstance(y, B):
-    reveal_type(x)  # revealed: A
-    reveal_type(y)  # revealed: B
-else:
-    # No narrowing: Only-one or both checks might have failed
-    reveal_type(x)  # revealed: A | B
-    reveal_type(y)  # revealed: A | B
-
-reveal_type(x)  # revealed: A | B
-reveal_type(y)  # revealed: A | B
-```
-
-## Narrowing in `or` conditional
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) or isinstance(x, B):
-    reveal_type(x)  # revealed:  A | B
-else:
-    reveal_type(x)  # revealed:  C & ~A & ~B
-```
-
-## In `or`, all arms should add constraint in order to narrow
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-def bool_instance() -> bool:
-    return True
-
-x = instance()
-
-if isinstance(x, A) or isinstance(x, B) or bool_instance():
-    reveal_type(x)  # revealed:  A | B | C
-else:
-    reveal_type(x)  # revealed:  C & ~A & ~B
-```
-
-## in `or`, all arms should narrow the same set of symbols
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-y = instance()
-
-if isinstance(x, A) or isinstance(y, A):
-    # The predicate might be satisfied by the right side, so the type of `x` can’t be narrowed down here.
-    reveal_type(x)  # revealed:  A | B | C
-    # The same for `y`
-    reveal_type(y)  # revealed:  A | B | C
-else:
-    reveal_type(x)  # revealed:  B & ~A | C & ~A
-    reveal_type(y)  # revealed:  B & ~A | C & ~A
-
-if (isinstance(x, A) and isinstance(y, A)) or (isinstance(x, B) and isinstance(y, B)):
-    # Here, types of `x` and `y` can be narrowd since all `or` arms constraint them.
-    reveal_type(x)  # revealed:  A | B
-    reveal_type(y)  # revealed:  A | B
-else:
-    reveal_type(x)  # revealed:  A | B | C
-    reveal_type(y)  # revealed:  A | B | C
-```
-
-## mixing `and` and `not`
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-
-if isinstance(x, B) and not isinstance(x, C):
-    reveal_type(x)  # revealed:  B & ~C
-else:
-    # ~(B & ~C) -> ~B | C -> (A & ~B) | (C & ~B) | C -> (A & ~B) | C
-    reveal_type(x)  # revealed: A & ~B | C
-```
-
-## mixing `or` and `not`
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-
-if isinstance(x, B) or not isinstance(x, C):
-    reveal_type(x)  # revealed: B | A & ~C
-else:
-    reveal_type(x)  # revealed: C & ~B
-```
-
-## `or` with nested `and`
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) or (isinstance(x, B) and not isinstance(x, C)):
-    reveal_type(x)  # revealed:  A | B & ~C
-else:
-    # ~(A | (B & ~C)) -> ~A & ~(B & ~C) -> ~A & (~B | C) -> (~A & C) | (~A ~ B)
-    reveal_type(x)  # revealed:  C & ~A
-```
-
-## `and` with nested `or`
-
-```py
-class A: ...
-class B: ...
-class C: ...
-
-def instance() -> A | B | C:
-    return A()
-
-x = instance()
-
-if isinstance(x, A) and (isinstance(x, B) or not isinstance(x, C)):
-    # A & (B | ~C) -> (A & B) | (A & ~C)
-    reveal_type(x)  # revealed:  A & B | A & ~C
-else:
-    # ~((A & B) | (A & ~C)) ->
-    # ~(A & B) & ~(A & ~C) ->
-    # (~A | ~B) & (~A | C) ->
-    # [(~A | ~B) & ~A] | [(~A | ~B) & C] ->
-    # ~A | (~A & C) | (~B & C) ->
-    # ~A | (C & ~B) ->
-    # ~A | (C & ~B)  The positive side of ~A is  A | B | C ->
-    reveal_type(x)  # revealed:  B & ~A | C & ~A | C & ~B
-```
-
-## Boolean expression internal narrowing
-
-```py
-def optional_string() -> str | None:
-    return None
-
-x = optional_string()
-y = optional_string()
-
-if x is None and y is not x:
-    reveal_type(y)  # revealed: str
-
-# Neither of the conditions alone is sufficient for narrowing y's type:
-if x is None:
-    reveal_type(y)  # revealed: str | None
-
-if y is not x:
-    reveal_type(y)  # revealed: str | None
-```

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

@@ -1,247 +0,0 @@
-# Narrowing for `issubclass` checks
-
-Narrowing for `issubclass(class, classinfo)` expressions.
-
-## `classinfo` is a single type
-
-### Basic example
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-if issubclass(t, bytes):
-    reveal_type(t)  # revealed: Never
-
-if issubclass(t, object):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-else:
-    reveal_type(t)  # revealed: Literal[str]
-
-if issubclass(t, str):
-    reveal_type(t)  # revealed: Literal[str]
-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Never
-```
-
-### Proper narrowing in `elif` and `else` branches
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str if flag() else bytes
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-else:
-    reveal_type(t)  # revealed: Literal[str, bytes]
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-elif issubclass(t, str):
-    reveal_type(t)  # revealed: Literal[str]
-else:
-    reveal_type(t)  # revealed: Literal[bytes]
-```
-
-### Multiple derived classes
-
-```py
-class Base: ...
-class Derived1(Base): ...
-class Derived2(Base): ...
-class Unrelated: ...
-
-def flag() -> bool: ...
-
-t1 = Derived1 if flag() else Derived2
-
-if issubclass(t1, Base):
-    reveal_type(t1)  # revealed: Literal[Derived1, Derived2]
-
-if issubclass(t1, Derived1):
-    reveal_type(t1)  # revealed: Literal[Derived1]
-else:
-    reveal_type(t1)  # revealed: Literal[Derived2]
-
-t2 = Derived1 if flag() else Base
-
-if issubclass(t2, Base):
-    reveal_type(t2)  # revealed: Literal[Derived1, Base]
-
-t3 = Derived1 if flag() else Unrelated
-
-if issubclass(t3, Base):
-    reveal_type(t3)  # revealed: Literal[Derived1]
-else:
-    reveal_type(t3)  # revealed: Literal[Unrelated]
-```
-
-### Narrowing for non-literals
-
-```py
-class A: ...
-class B: ...
-
-def get_class() -> type[object]: ...
-
-t = get_class()
-
-if issubclass(t, A):
-    reveal_type(t)  # revealed: type[A]
-    if issubclass(t, B):
-        reveal_type(t)  # revealed: type[A] & type[B]
-else:
-    reveal_type(t)  # revealed: type[object] & ~type[A]
-```
-
-### Handling of `None`
-
-```py
-# TODO: this error should ideally go away once we (1) understand `sys.version_info` branches,
-# and (2) set the target Python version for this test to 3.10.
-# error: [possibly-unbound-import] "Member `NoneType` of module `types` is possibly unbound"
-from types import NoneType
-
-def flag() -> bool: ...
-
-t = int if flag() else NoneType
-
-if issubclass(t, NoneType):
-    reveal_type(t)  # revealed: Literal[NoneType]
-
-if issubclass(t, type(None)):
-    # TODO: this should be just `Literal[NoneType]`
-    reveal_type(t)  # revealed: Literal[int, NoneType]
-```
-
-## `classinfo` contains multiple types
-
-### (Nested) tuples of types
-
-```py
-class Unrelated: ...
-
-def flag() -> bool: ...
-
-t = int if flag() else str if flag() else bytes
-
-if issubclass(t, (int, (Unrelated, (bytes,)))):
-    reveal_type(t)  # revealed: Literal[int, bytes]
-else:
-    reveal_type(t)  # revealed: Literal[str]
-```
-
-## Special cases
-
-### Emit a diagnostic if the first argument is of wrong type
-
-#### Too wide
-
-`type[object]` is a subtype of `object`, but not every `object` can be passed as the first argument
-to `issubclass`:
-
-```py
-class A: ...
-
-def get_object() -> object: ...
-
-t = get_object()
-
-# TODO: we should emit a diagnostic here
-if issubclass(t, A):
-    reveal_type(t)  # revealed: type[A]
-```
-
-#### Wrong
-
-`Literal[1]` and `type` are entirely disjoint, so the inferred type of `Literal[1] & type[int]` is
-eagerly simplified to `Never` as a result of the type narrowing in the `if issubclass(t, int)`
-branch:
-
-```py
-t = 1
-
-# TODO: we should emit a diagnostic here
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Never
-```
-
-### Do not use custom `issubclass` for narrowing
-
-```py
-def issubclass(c, ci):
-    return True
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int, str]
-```
-
-### Do support narrowing if `issubclass` is aliased
-
-```py
-issubclass_alias = issubclass
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if issubclass_alias(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-```
-
-### Do support narrowing if `issubclass` is imported
-
-```py
-from builtins import issubclass as imported_issubclass
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if imported_issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-```
-
-### Do not narrow if second argument is not a proper `classinfo` argument
-
-```py
-from typing import Any
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, "str"):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, (bytes, "str")):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, Any):
-    reveal_type(t)  # revealed: Literal[int, str]
-```
-
-### Do not narrow if there are keyword arguments
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-# TODO: this should cause us to emit a diagnostic
-# (`issubclass` has no `foo` parameter)
-if issubclass(t, int, foo="bar"):
-    reveal_type(t)  # revealed: Literal[int, str]
-```

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

@@ -1,152 +0,0 @@
-# Narrowing for checks involving `type(x)`
-
-## `type(x) is C`
-
-```py
-class A: ...
-class B: ...
-
-def get_a_or_b() -> A | B:
-    return A()
-
-x = get_a_or_b()
-
-if type(x) is A:
-    reveal_type(x)  # revealed: A
-else:
-    # It would be wrong to infer `B` here. The type
-    # of `x` could be a subclass of `A`, so we need
-    # to infer the full union type:
-    reveal_type(x)  # revealed: A | B
-```
-
-## `type(x) is not C`
-
-```py
-class A: ...
-class B: ...
-
-def get_a_or_b() -> A | B:
-    return A()
-
-x = get_a_or_b()
-
-if type(x) is not A:
-    # Same reasoning as above: no narrowing should occur here.
-    reveal_type(x)  # revealed: A | B
-else:
-    reveal_type(x)  # revealed: A
-```
-
-## `type(x) == C`, `type(x) != C`
-
-No narrowing can occur for equality comparisons, since there might be a custom `__eq__`
-implementation on the metaclass.
-
-TODO: Narrowing might be possible in some cases where the classes themselves are `@final` or their
-metaclass is `@final`.
-
-```py
-class IsEqualToEverything(type):
-    def __eq__(cls, other):
-        return True
-
-class A(metaclass=IsEqualToEverything): ...
-class B(metaclass=IsEqualToEverything): ...
-
-def get_a_or_b() -> A | B:
-    return B()
-
-x = get_a_or_b()
-
-if type(x) == A:
-    reveal_type(x)  # revealed: A | B
-
-if type(x) != A:
-    reveal_type(x)  # revealed: A | B
-```
-
-## No narrowing for custom `type` callable
-
-```py
-class A: ...
-class B: ...
-
-def type(x):
-    return int
-
-def get_a_or_b() -> A | B:
-    return A()
-
-x = get_a_or_b()
-
-if type(x) is A:
-    reveal_type(x)  # revealed: A | B
-else:
-    reveal_type(x)  # revealed: A | B
-```
-
-## No narrowing for multiple arguments
-
-No narrowing should occur if `type` is used to dynamically create a class:
-
-```py
-def get_str_or_int() -> str | int:
-    return "test"
-
-x = get_str_or_int()
-
-if type(x, (), {}) is str:
-    reveal_type(x)  # revealed: str | int
-else:
-    reveal_type(x)  # revealed: str | int
-```
-
-## No narrowing for keyword arguments
-
-`type` can't be used with a keyword argument:
-
-```py
-def get_str_or_int() -> str | int:
-    return "test"
-
-x = get_str_or_int()
-
-# TODO: we could issue a diagnostic here
-if type(object=x) is str:
-    reveal_type(x)  # revealed: str | int
-```
-
-## Narrowing if `type` is aliased
-
-```py
-class A: ...
-class B: ...
-
-alias_for_type = type
-
-def get_a_or_b() -> A | B:
-    return A()
-
-x = get_a_or_b()
-
-if alias_for_type(x) is A:
-    reveal_type(x)  # revealed: A
-```
-
-## Limitations
-
-```py
-class Base: ...
-class Derived(Base): ...
-
-def get_base() -> Base:
-    return Base()
-
-x = get_base()
-
-if type(x) is Base:
-    # Ideally, this could be narrower, but there is now way to
-    # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
-    reveal_type(x)  # revealed: Base
-```

crates/red_knot_python_semantic/resources/mdtest/regression/14334_diagnostics_in_wrong_file.md

@@ -1,13 +0,0 @@
-# Regression test for #14334
-
-Regression test for [this issue](https://github.com/astral-sh/ruff/issues/14334).
-
-```py path=base.py
-# error: [invalid-base]
-class Base(2): ...
-```
-
-```py path=a.py
-# No error here
-from base import Base
-```

crates/red_knot_python_semantic/resources/mdtest/scopes/moduletype_attrs.md

@@ -58,9 +58,11 @@ reveal_type(typing.__name__)  # revealed: str
 reveal_type(typing.__init__)  # revealed: Literal[__init__]
 
 # These come from `builtins.object`, not `types.ModuleType`:
-reveal_type(typing.__eq__)  # revealed: Literal[__eq__]
-
-reveal_type(typing.__class__)  # revealed: Literal[type]
+# TODO: we don't currently understand `types.ModuleType` as inheriting from `object`;
+# these should not reveal `Unknown`:
+reveal_type(typing.__eq__)  # revealed: Unknown
+reveal_type(typing.__class__)  # revealed: Unknown
+reveal_type(typing.__module__)  # revealed: Unknown
 
 # TODO: needs support for attribute access on instances, properties and generics;
 # should be `dict[str, Any]`
@@ -74,7 +76,6 @@ we're dealing with:
 ```py path=__getattr__.py
 import typing
 
-# error: [unresolved-attribute]
 reveal_type(typing.__getattr__)  # revealed: Unknown
 ```
 

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

@@ -6,12 +6,7 @@ In type stubs, classes can reference themselves in their base class definitions.
 `typeshed`, we have `class str(Sequence[str]): ...`.
 
 ```py path=a.pyi
-class Foo[T]: ...
+class C(C): ...
 
-# TODO: actually is subscriptable
-# error: [non-subscriptable]
-class Bar(Foo[Bar]): ...
-
-reveal_type(Bar)  # revealed: Literal[Bar]
-reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
+reveal_type(C)  # revealed: Literal[C]
 ```

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

@@ -39,8 +39,7 @@ reveal_type(UnionClassGetItem[0])  # revealed: str | int
 ## Class getitem with class union
 
 ```py
-def bool_instance() -> bool:
-    return True
+flag = True
 
 class A:
     def __class_getitem__(cls, item: int) -> str:
@@ -50,7 +49,7 @@ class B:
     def __class_getitem__(cls, item: int) -> int:
         return item
 
-x = A if bool_instance() else B
+x = A if flag else B
 
 reveal_type(x)  # revealed: Literal[A, B]
 reveal_type(x[0])  # revealed: str | int

crates/red_knot_python_semantic/resources/mdtest/sys_version_info.md

@@ -1,139 +0,0 @@
-# `sys.version_info`
-
-## The type of `sys.version_info`
-
-The type of `sys.version_info` is `sys._version_info`, at least according to typeshed's stubs (which
-we treat as the single source of truth for the standard library). This is quite a complicated type
-in typeshed, so there are many things we don't fully understand about the type yet; this is the
-source of several TODOs in this test file. Many of these TODOs should be naturally fixed as we
-implement more type-system features in the future.
-
-```py
-import sys
-
-reveal_type(sys.version_info)  # revealed: _version_info
-```
-
-## Literal types from comparisons
-
-Comparing `sys.version_info` with a 2-element tuple of literal integers always produces a `Literal`
-type:
-
-```py
-import sys
-
-reveal_type(sys.version_info >= (3, 9))  # revealed: Literal[True]
-reveal_type((3, 9) <= sys.version_info)  # revealed: Literal[True]
-
-reveal_type(sys.version_info > (3, 9))  # revealed: Literal[True]
-reveal_type((3, 9) < sys.version_info)  # revealed: Literal[True]
-
-reveal_type(sys.version_info < (3, 9))  # revealed: Literal[False]
-reveal_type((3, 9) > sys.version_info)  # revealed: Literal[False]
-
-reveal_type(sys.version_info <= (3, 9))  # revealed: Literal[False]
-reveal_type((3, 9) >= sys.version_info)  # revealed: Literal[False]
-
-reveal_type(sys.version_info == (3, 9))  # revealed: Literal[False]
-reveal_type((3, 9) == sys.version_info)  # revealed: Literal[False]
-
-reveal_type(sys.version_info != (3, 9))  # revealed: Literal[True]
-reveal_type((3, 9) != sys.version_info)  # revealed: Literal[True]
-```
-
-## Non-literal types from comparisons
-
-Comparing `sys.version_info` with tuples of other lengths will sometimes produce `Literal` types,
-sometimes not:
-
-```py
-import sys
-
-reveal_type(sys.version_info >= (3, 9, 1))  # revealed: bool
-reveal_type(sys.version_info >= (3, 9, 1, "final", 0))  # revealed: bool
-
-# TODO: While this won't fail at runtime, the user has probably made a mistake
-# if they're comparing a tuple of length >5 with `sys.version_info`
-# (`sys.version_info` is a tuple of length 5). It might be worth
-# emitting a lint diagnostic of some kind warning them about the probable error?
-reveal_type(sys.version_info >= (3, 9, 1, "final", 0, 5))  # revealed: bool
-
-# TODO: this should be `Literal[False]`; see #14279
-reveal_type(sys.version_info == (3, 9, 1, "finallllll", 0))  # revealed: bool
-```
-
-## Imports and aliases
-
-Comparisons with `sys.version_info` still produce literal types, even if the symbol is aliased to
-another name:
-
-```py
-from sys import version_info
-from sys import version_info as foo
-
-reveal_type(version_info >= (3, 9))  # revealed: Literal[True]
-reveal_type(foo >= (3, 9))  # revealed: Literal[True]
-
-bar = version_info
-reveal_type(bar >= (3, 9))  # revealed: Literal[True]
-```
-
-## Non-stdlib modules named `sys`
-
-Only comparisons with the symbol `version_info` from the `sys` module produce literal types:
-
-```py path=package/__init__.py
-```
-
-```py path=package/sys.py
-version_info: tuple[int, int] = (4, 2)
-```
-
-```py path=package/script.py
-from .sys import version_info
-
-reveal_type(version_info >= (3, 9))  # revealed: bool
-```
-
-## Accessing fields by name
-
-The fields of `sys.version_info` can be accessed by name:
-
-```py path=a.py
-import sys
-
-reveal_type(sys.version_info.major >= 3)  # revealed: Literal[True]
-reveal_type(sys.version_info.minor >= 9)  # revealed: Literal[True]
-reveal_type(sys.version_info.minor >= 10)  # revealed: Literal[False]
-```
-
-But the `micro`, `releaselevel` and `serial` fields are inferred as `@Todo` until we support
-properties on instance types:
-
-```py path=b.py
-import sys
-
-reveal_type(sys.version_info.micro)  # revealed: @Todo
-reveal_type(sys.version_info.releaselevel)  # revealed: @Todo
-reveal_type(sys.version_info.serial)  # revealed: @Todo
-```
-
-## Accessing fields by index/slice
-
-The fields of `sys.version_info` can be accessed by index or by slice:
-
-```py
-import sys
-
-reveal_type(sys.version_info[0] < 3)  # revealed: Literal[False]
-reveal_type(sys.version_info[1] > 9)  # revealed: Literal[False]
-
-# revealed: tuple[Literal[3], Literal[9], int, Literal["alpha", "beta", "candidate", "final"], int]
-reveal_type(sys.version_info[:5])
-
-reveal_type(sys.version_info[:2] >= (3, 9))  # revealed: Literal[True]
-reveal_type(sys.version_info[0:2] >= (3, 10))  # revealed: Literal[False]
-reveal_type(sys.version_info[:3] >= (3, 10, 1))  # revealed: Literal[False]
-reveal_type(sys.version_info[3] == "final")  # revealed: bool
-reveal_type(sys.version_info[3] == "finalllllll")  # revealed: Literal[False]
-```

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

@@ -1,10 +1,6 @@
-# Invert, UAdd, USub
-
-## Instance
+# Unary Operations
 
 ```py
-from typing import Literal
-
 class Number:
     def __init__(self, value: int):
         self.value = 1
@@ -22,7 +18,7 @@ a = Number()
 
 reveal_type(+a)  # revealed: int
 reveal_type(-a)  # revealed: int
-reveal_type(~a)  # revealed: Literal[True]
+reveal_type(~a)  # revealed: @Todo
 
 class NoDunder: ...
 

crates/red_knot_python_semantic/resources/mdtest/unary/not.md

@@ -10,6 +10,8 @@ reveal_type(not not None)  # revealed: Literal[False]
 ## Function
 
 ```py
+from typing import reveal_type
+
 def f():
     return 1
 
@@ -113,101 +115,3 @@ reveal_type(not ())  # revealed: Literal[True]
 reveal_type(not ("hello",))  # revealed: Literal[False]
 reveal_type(not (1, "hello"))  # revealed: Literal[False]
 ```
-
-## Instance
-
-Not operator is inferred based on
-<https://docs.python.org/3/library/stdtypes.html#truth-value-testing>. An instance is True or False
-if the `__bool__` method says so.
-
-At runtime, the `__len__` method is a fallback for `__bool__`, but we can't make use of that. If we
-have a class that defines `__len__` but not `__bool__`, it is possible that any subclass could add a
-`__bool__` method that would invalidate whatever conclusion we drew from `__len__`. So instances of
-classes without a `__bool__` method, with or without `__len__`, must be inferred as unknown
-truthiness.
-
-```py
-class AlwaysTrue:
-    def __bool__(self) -> Literal[True]:
-        return True
-
-# revealed: Literal[False]
-reveal_type(not AlwaysTrue())
-
-class AlwaysFalse:
-    def __bool__(self) -> Literal[False]:
-        return False
-
-# revealed: Literal[True]
-reveal_type(not AlwaysFalse())
-
-# We don't get into a cycle if someone sets their `__bool__` method to the `bool` builtin:
-class BoolIsBool:
-    __bool__ = bool
-
-# revealed: bool
-reveal_type(not BoolIsBool())
-
-# At runtime, no `__bool__` and no `__len__` means truthy, but we can't rely on that, because
-# a subclass could add a `__bool__` method.
-class NoBoolMethod: ...
-
-# revealed: bool
-reveal_type(not NoBoolMethod())
-
-# And we can't rely on `__len__` for the same reason: a subclass could add `__bool__`.
-class LenZero:
-    def __len__(self) -> Literal[0]:
-        return 0
-
-# revealed: bool
-reveal_type(not LenZero())
-
-class LenNonZero:
-    def __len__(self) -> Literal[1]:
-        return 1
-
-# revealed: bool
-reveal_type(not LenNonZero())
-
-class WithBothLenAndBool1:
-    def __bool__(self) -> Literal[False]:
-        return False
-
-    def __len__(self) -> Literal[2]:
-        return 2
-
-# revealed: Literal[True]
-reveal_type(not WithBothLenAndBool1())
-
-class WithBothLenAndBool2:
-    def __bool__(self) -> Literal[True]:
-        return True
-
-    def __len__(self) -> Literal[0]:
-        return 0
-
-# revealed: Literal[False]
-reveal_type(not WithBothLenAndBool2())
-
-# TODO: raise diagnostic when __bool__ method is not valid: [unsupported-operator] "Method __bool__ for type `MethodBoolInvalid` should return `bool`, returned type `int`"
-# https://docs.python.org/3/reference/datamodel.html#object.__bool__
-class MethodBoolInvalid:
-    def __bool__(self) -> int:
-        return 0
-
-# revealed: bool
-reveal_type(not MethodBoolInvalid())
-
-# Don't trust a possibly-unbound `__bool__` method:
-def get_flag() -> bool:
-    return True
-
-class PossiblyUnboundBool:
-    if get_flag():
-        def __bool__(self) -> Literal[False]:
-            return False
-
-# revealed: bool
-reveal_type(not PossiblyUnboundBool())
-```

crates/red_knot_python_semantic/resources/mdtest/unpacking.md

@@ -145,8 +145,13 @@ reveal_type(f)  # revealed: Unknown
 
 ### Non-iterable unpacking
 
+TODO: Remove duplicate diagnostics. This is happening because for a sequence-like assignment target,
+multiple definitions are created and the inference engine runs on each of them which results in
+duplicate diagnostics.
+
 ```py
 # error: "Object of type `Literal[1]` is not iterable"
+# error: "Object of type `Literal[1]` is not iterable"
 a, b = 1
 reveal_type(a)  # revealed: Unknown
 reveal_type(b)  # revealed: Unknown

crates/red_knot_python_semantic/src/lib.rs

@@ -22,7 +22,6 @@ pub(crate) mod site_packages;
 mod stdlib;
 pub(crate) mod symbol;
 pub mod types;
-mod unpack;
 mod util;
 
 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;

crates/red_knot_python_semantic/src/module_resolver/typeshed.rs

@@ -459,11 +459,11 @@ foo: 3.8-   # trailing comment
 ";
         let parsed_versions = TypeshedVersions::from_str(VERSIONS).unwrap();
         assert_eq!(parsed_versions.len(), 3);
-        assert_snapshot!(parsed_versions.to_string(), @r"
+        assert_snapshot!(parsed_versions.to_string(), @r###"
         bar: 2.7-3.10
         bar.baz: 3.1-3.9
         foo: 3.8-
-        "
+        "###
         );
     }
 

crates/red_knot_python_semantic/src/node_key.rs

@@ -1,14 +1,14 @@
-use ruff_python_ast::AnyNodeRef;
+use ruff_python_ast::{AnyNodeRef, NodeKind};
+use ruff_text_size::{Ranged, TextRange};
 
 /// Compact key for a node for use in a hash map.
 ///
-/// Stores the memory address of the node, because using the range and the kind
-/// of the node is not enough to uniquely identify them in ASTs resulting from
-/// invalid syntax. For example, parsing the input `for` results in a `StmtFor`
-/// AST node where both the `target` and the `iter` field are `ExprName` nodes
-/// with the same (empty) range `3..3`.
+/// Compares two nodes by their kind and text range.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
-pub(super) struct NodeKey(usize);
+pub(super) struct NodeKey {
+    kind: NodeKind,
+    range: TextRange,
+}
 
 impl NodeKey {
     pub(super) fn from_node<'a, N>(node: N) -> Self
@@ -16,6 +16,9 @@ impl NodeKey {
         N: Into<AnyNodeRef<'a>>,
     {
         let node = node.into();
-        NodeKey(node.as_ptr().as_ptr() as usize)
+        NodeKey {
+            kind: node.kind(),
+            range: node.range(),
+        }
     }
 }

crates/red_knot_python_semantic/src/program.rs

@@ -54,7 +54,6 @@ impl Program {
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct ProgramSettings {
     pub target_version: PythonVersion,
     pub search_paths: SearchPathSettings,
@@ -62,7 +61,6 @@ pub struct ProgramSettings {
 
 /// Configures the search paths for module resolution.
 #[derive(Eq, PartialEq, Debug, Clone)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct SearchPathSettings {
     /// List of user-provided paths that should take first priority in the module resolution.
     /// Examples in other type checkers are mypy's MYPYPATH environment variable,
@@ -93,7 +91,6 @@ impl SearchPathSettings {
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub enum SitePackages {
     Derived {
         venv_path: SystemPathBuf,

crates/red_knot_python_semantic/src/python_version.rs

@@ -5,7 +5,6 @@ use std::fmt;
 /// Unlike the `TargetVersion` enums in the CLI crates,
 /// this does not necessarily represent a Python version that we actually support.
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct PythonVersion {
     pub major: u8,
     pub minor: u8,
@@ -39,7 +38,7 @@ impl PythonVersion {
 
 impl Default for PythonVersion {
     fn default() -> Self {
-        Self::PY39
+        Self::PY38
     }
 }
 

crates/red_knot_python_semantic/src/semantic_index.rs

@@ -125,7 +125,6 @@ impl<'db> SemanticIndex<'db> {
     ///
     /// Use the Salsa cached [`symbol_table()`] query if you only need the
     /// symbol table for a single scope.
-    #[track_caller]
     pub(super) fn symbol_table(&self, scope_id: FileScopeId) -> Arc<SymbolTable> {
         self.symbol_tables[scope_id].clone()
     }
@@ -134,18 +133,15 @@ impl<'db> SemanticIndex<'db> {
     ///
     /// Use the Salsa cached [`use_def_map()`] query if you only need the
     /// use-def map for a single scope.
-    #[track_caller]
     pub(super) fn use_def_map(&self, scope_id: FileScopeId) -> Arc<UseDefMap> {
         self.use_def_maps[scope_id].clone()
     }
 
-    #[track_caller]
     pub(crate) fn ast_ids(&self, scope_id: FileScopeId) -> &AstIds {
         &self.ast_ids[scope_id]
     }
 
     /// Returns the ID of the `expression`'s enclosing scope.
-    #[track_caller]
     pub(crate) fn expression_scope_id(
         &self,
         expression: impl Into<ExpressionNodeKey>,
@@ -155,13 +151,11 @@ impl<'db> SemanticIndex<'db> {
 
     /// Returns the [`Scope`] of the `expression`'s enclosing scope.
     #[allow(unused)]
-    #[track_caller]
     pub(crate) fn expression_scope(&self, expression: impl Into<ExpressionNodeKey>) -> &Scope {
         &self.scopes[self.expression_scope_id(expression)]
     }
 
     /// Returns the [`Scope`] with the given id.
-    #[track_caller]
     pub(crate) fn scope(&self, id: FileScopeId) -> &Scope {
         &self.scopes[id]
     }
@@ -178,7 +172,6 @@ impl<'db> SemanticIndex<'db> {
 
     /// Returns the parent scope of `scope_id`.
     #[allow(unused)]
-    #[track_caller]
     pub(crate) fn parent_scope(&self, scope_id: FileScopeId) -> Option<&Scope> {
         Some(&self.scopes[self.parent_scope_id(scope_id)?])
     }
@@ -202,7 +195,6 @@ impl<'db> SemanticIndex<'db> {
     }
 
     /// Returns the [`Definition`] salsa ingredient for `definition_key`.
-    #[track_caller]
     pub(crate) fn definition(
         &self,
         definition_key: impl Into<DefinitionNodeKey>,
@@ -214,7 +206,6 @@ impl<'db> SemanticIndex<'db> {
     /// Panics if we have no expression ingredient for that node. We can only call this method for
     /// standalone-inferable expressions, which we call `add_standalone_expression` for in
     /// [`SemanticIndexBuilder`].
-    #[track_caller]
     pub(crate) fn expression(
         &self,
         expression_key: impl Into<ExpressionNodeKey>,
@@ -222,18 +213,8 @@ impl<'db> SemanticIndex<'db> {
         self.expressions_by_node[&expression_key.into()]
     }
 
-    pub(crate) fn try_expression(
-        &self,
-        expression_key: impl Into<ExpressionNodeKey>,
-    ) -> Option<Expression<'db>> {
-        self.expressions_by_node
-            .get(&expression_key.into())
-            .copied()
-    }
-
     /// Returns the id of the scope that `node` creates. This is different from [`Definition::scope`] which
     /// returns the scope in which that definition is defined in.
-    #[track_caller]
     pub(crate) fn node_scope(&self, node: NodeWithScopeRef) -> FileScopeId {
         self.scopes_by_node[&node.node_key()]
     }

crates/red_knot_python_semantic/src/semantic_index/ast_ids.rs

@@ -49,50 +49,56 @@ fn ast_ids<'db>(db: &'db dyn Db, scope: ScopeId) -> &'db AstIds {
     semantic_index(db, scope.file(db)).ast_ids(scope.file_scope_id(db))
 }
 
+pub trait HasScopedUseId {
+    /// The type of the ID uniquely identifying the use.
+    type Id: Copy;
+
+    /// Returns the ID that uniquely identifies the use in `scope`.
+    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id;
+}
+
 /// Uniquely identifies a use of a name in a [`crate::semantic_index::symbol::FileScopeId`].
 #[newtype_index]
 pub struct ScopedUseId;
 
-pub trait HasScopedUseId {
-    /// Returns the ID that uniquely identifies the use in `scope`.
-    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedUseId;
-}
-
 impl HasScopedUseId for ast::ExprName {
-    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedUseId {
+    type Id = ScopedUseId;
+
+    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id {
         let expression_ref = ExpressionRef::from(self);
         expression_ref.scoped_use_id(db, scope)
     }
 }
 
 impl HasScopedUseId for ast::ExpressionRef<'_> {
-    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedUseId {
+    type Id = ScopedUseId;
+
+    fn scoped_use_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id {
         let ast_ids = ast_ids(db, scope);
         ast_ids.use_id(*self)
     }
 }
 
+pub trait HasScopedAstId {
+    /// The type of the ID uniquely identifying the node.
+    type Id: Copy;
+
+    /// Returns the ID that uniquely identifies the node in `scope`.
+    fn scoped_ast_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id;
+}
+
 /// Uniquely identifies an [`ast::Expr`] in a [`crate::semantic_index::symbol::FileScopeId`].
 #[newtype_index]
 pub struct ScopedExpressionId;
 
-pub trait HasScopedExpressionId {
-    /// Returns the ID that uniquely identifies the node in `scope`.
-    fn scoped_expression_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedExpressionId;
-}
-
-impl<T: HasScopedExpressionId> HasScopedExpressionId for Box<T> {
-    fn scoped_expression_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedExpressionId {
-        self.as_ref().scoped_expression_id(db, scope)
-    }
-}
-
 macro_rules! impl_has_scoped_expression_id {
     ($ty: ty) => {
-        impl HasScopedExpressionId for $ty {
-            fn scoped_expression_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedExpressionId {
+        impl HasScopedAstId for $ty {
+            type Id = ScopedExpressionId;
+
+            fn scoped_ast_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id {
                 let expression_ref = ExpressionRef::from(self);
-                expression_ref.scoped_expression_id(db, scope)
+                expression_ref.scoped_ast_id(db, scope)
             }
         }
     };
@@ -132,20 +138,29 @@ impl_has_scoped_expression_id!(ast::ExprSlice);
 impl_has_scoped_expression_id!(ast::ExprIpyEscapeCommand);
 impl_has_scoped_expression_id!(ast::Expr);
 
-impl HasScopedExpressionId for ast::ExpressionRef<'_> {
-    fn scoped_expression_id(&self, db: &dyn Db, scope: ScopeId) -> ScopedExpressionId {
+impl HasScopedAstId for ast::ExpressionRef<'_> {
+    type Id = ScopedExpressionId;
+
+    fn scoped_ast_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id {
         let ast_ids = ast_ids(db, scope);
         ast_ids.expression_id(*self)
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub(super) struct AstIdsBuilder {
     expressions_map: FxHashMap<ExpressionNodeKey, ScopedExpressionId>,
     uses_map: FxHashMap<ExpressionNodeKey, ScopedUseId>,
 }
 
 impl AstIdsBuilder {
+    pub(super) fn new() -> Self {
+        Self {
+            expressions_map: FxHashMap::default(),
+            uses_map: FxHashMap::default(),
+        }
+    }
+
     /// Adds `expr` to the expression ids map and returns its id.
     pub(super) fn record_expression(&mut self, expr: &ast::Expr) -> ScopedExpressionId {
         let expression_id = self.expressions_map.len().into();

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -25,13 +25,12 @@ use crate::semantic_index::symbol::{
 };
 use crate::semantic_index::use_def::{FlowSnapshot, UseDefMapBuilder};
 use crate::semantic_index::SemanticIndex;
-use crate::unpack::Unpack;
 use crate::Db;
 
 use super::constraint::{Constraint, ConstraintNode, PatternConstraint};
 use super::definition::{
-    DefinitionCategory, ExceptHandlerDefinitionNodeRef, MatchPatternDefinitionNodeRef,
-    WithItemDefinitionNodeRef,
+    AssignmentKind, DefinitionCategory, ExceptHandlerDefinitionNodeRef,
+    MatchPatternDefinitionNodeRef, WithItemDefinitionNodeRef,
 };
 
 mod except_handlers;
@@ -47,7 +46,6 @@ pub(super) struct SemanticIndexBuilder<'db> {
     current_assignments: Vec<CurrentAssignment<'db>>,
     /// The match case we're currently visiting.
     current_match_case: Option<CurrentMatchCase<'db>>,
-
     /// Flow states at each `break` in the current loop.
     loop_break_states: Vec<FlowSnapshot>,
     /// Per-scope contexts regarding nested `try`/`except` statements
@@ -114,21 +112,27 @@ impl<'db> SemanticIndexBuilder<'db> {
     fn push_scope_with_parent(&mut self, node: NodeWithScopeRef, parent: Option<FileScopeId>) {
         let children_start = self.scopes.next_index() + 1;
 
-        #[allow(unsafe_code)]
         let scope = Scope {
             parent,
-            // SAFETY: `node` is guaranteed to be a child of `self.module`
-            node: unsafe { node.to_kind(self.module.clone()) },
+            kind: node.scope_kind(),
             descendents: children_start..children_start,
         };
         self.try_node_context_stack_manager.enter_nested_scope();
 
         let file_scope_id = self.scopes.push(scope);
-        self.symbol_tables.push(SymbolTableBuilder::default());
-        self.use_def_maps.push(UseDefMapBuilder::default());
-        let ast_id_scope = self.ast_ids.push(AstIdsBuilder::default());
+        self.symbol_tables.push(SymbolTableBuilder::new());
+        self.use_def_maps.push(UseDefMapBuilder::new());
+        let ast_id_scope = self.ast_ids.push(AstIdsBuilder::new());
 
-        let scope_id = ScopeId::new(self.db, self.file, file_scope_id, countme::Count::default());
+        #[allow(unsafe_code)]
+        // SAFETY: `node` is guaranteed to be a child of `self.module`
+        let scope_id = ScopeId::new(
+            self.db,
+            self.file,
+            file_scope_id,
+            unsafe { node.to_kind(self.module.clone()) },
+            countme::Count::default(),
+        );
 
         self.scope_ids_by_scope.push(scope_id);
         self.scopes_by_node.insert(node.node_key(), file_scope_id);
@@ -199,10 +203,10 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.current_symbol_table().mark_symbol_used(id);
     }
 
-    fn add_definition(
+    fn add_definition<'a>(
         &mut self,
         symbol: ScopedSymbolId,
-        definition_node: impl Into<DefinitionNodeRef<'db>>,
+        definition_node: impl Into<DefinitionNodeRef<'a>>,
     ) -> Definition<'db> {
         let definition_node: DefinitionNodeRef<'_> = definition_node.into();
         #[allow(unsafe_code)]
@@ -281,12 +285,8 @@ impl<'db> SemanticIndexBuilder<'db> {
         debug_assert!(popped_assignment.is_some());
     }
 
-    fn current_assignment(&self) -> Option<CurrentAssignment<'db>> {
-        self.current_assignments.last().copied()
-    }
-
-    fn current_assignment_mut(&mut self) -> Option<&mut CurrentAssignment<'db>> {
-        self.current_assignments.last_mut()
+    fn current_assignment(&self) -> Option<&CurrentAssignment<'db>> {
+        self.current_assignments.last()
     }
 
     fn add_pattern_constraint(
@@ -373,11 +373,6 @@ impl<'db> SemanticIndexBuilder<'db> {
                 if let Some(default) = default {
                     self.visit_expr(default);
                 }
-                match type_param {
-                    ast::TypeParam::TypeVar(node) => self.add_definition(symbol, node),
-                    ast::TypeParam::ParamSpec(node) => self.add_definition(symbol, node),
-                    ast::TypeParam::TypeVarTuple(node) => self.add_definition(symbol, node),
-                };
             }
         }
 
@@ -450,7 +445,7 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.pop_scope();
     }
 
-    fn declare_parameter(&mut self, parameter: AnyParameterRef<'db>) {
+    fn declare_parameter(&mut self, parameter: AnyParameterRef) {
         let symbol = self.add_symbol(parameter.name().id().clone());
 
         let definition = self.add_definition(symbol, parameter);
@@ -624,48 +619,24 @@ where
             }
             ast::Stmt::Assign(node) => {
                 debug_assert_eq!(&self.current_assignments, &[]);
-
                 self.visit_expr(&node.value);
-                let value = self.add_standalone_expression(&node.value);
-
-                for target in &node.targets {
-                    // We only handle assignments to names and unpackings here, other targets like
-                    // attribute and subscript are handled separately as they don't create a new
-                    // definition.
-                    let current_assignment = match target {
-                        ast::Expr::List(_) | ast::Expr::Tuple(_) => {
-                            Some(CurrentAssignment::Assign {
-                                node,
-                                first: true,
-                                unpack: Some(Unpack::new(
-                                    self.db,
-                                    self.file,
-                                    self.current_scope(),
-                                    #[allow(unsafe_code)]
-                                    unsafe {
-                                        AstNodeRef::new(self.module.clone(), target)
-                                    },
-                                    value,
-                                    countme::Count::default(),
-                                )),
-                            })
-                        }
-                        ast::Expr::Name(_) => Some(CurrentAssignment::Assign {
-                            node,
-                            unpack: None,
-                            first: false,
-                        }),
+                self.add_standalone_expression(&node.value);
+                for (target_index, target) in node.targets.iter().enumerate() {
+                    let kind = match target {
+                        ast::Expr::List(_) | ast::Expr::Tuple(_) => Some(AssignmentKind::Sequence),
+                        ast::Expr::Name(_) => Some(AssignmentKind::Name),
                         _ => None,
                     };
-
-                    if let Some(current_assignment) = current_assignment {
-                        self.push_assignment(current_assignment);
+                    if let Some(kind) = kind {
+                        self.push_assignment(CurrentAssignment::Assign {
+                            assignment: node,
+                            target_index,
+                            kind,
+                        });
                     }
-
                     self.visit_expr(target);
-
-                    if current_assignment.is_some() {
-                        // Only need to pop in the case where we pushed something
+                    if kind.is_some() {
+                        // only need to pop in the case where we pushed something
                         self.pop_assignment();
                     }
                 }
@@ -676,18 +647,9 @@ where
                 if let Some(value) = &node.value {
                     self.visit_expr(value);
                 }
-
-                // See https://docs.python.org/3/library/ast.html#ast.AnnAssign
-                if matches!(
-                    *node.target,
-                    ast::Expr::Attribute(_) | ast::Expr::Subscript(_) | ast::Expr::Name(_)
-                ) {
-                    self.push_assignment(node.into());
-                    self.visit_expr(&node.target);
-                    self.pop_assignment();
-                } else {
-                    self.visit_expr(&node.target);
-                }
+                self.push_assignment(node.into());
+                self.visit_expr(&node.target);
+                self.pop_assignment();
             }
             ast::Stmt::AugAssign(
                 aug_assign @ ast::StmtAugAssign {
@@ -699,18 +661,9 @@ where
             ) => {
                 debug_assert_eq!(&self.current_assignments, &[]);
                 self.visit_expr(value);
-
-                // See https://docs.python.org/3/library/ast.html#ast.AugAssign
-                if matches!(
-                    **target,
-                    ast::Expr::Attribute(_) | ast::Expr::Subscript(_) | ast::Expr::Name(_)
-                ) {
-                    self.push_assignment(aug_assign.into());
-                    self.visit_expr(target);
-                    self.pop_assignment();
-                } else {
-                    self.visit_expr(target);
-                }
+                self.push_assignment(aug_assign.into());
+                self.visit_expr(target);
+                self.pop_assignment();
             }
             ast::Stmt::If(node) => {
                 self.visit_expr(&node.test);
@@ -1017,19 +970,19 @@ where
                 }
 
                 if is_definition {
-                    match self.current_assignment() {
+                    match self.current_assignment().copied() {
                         Some(CurrentAssignment::Assign {
-                            node,
-                            first,
-                            unpack,
+                            assignment,
+                            target_index,
+                            kind,
                         }) => {
                             self.add_definition(
                                 symbol,
                                 AssignmentDefinitionNodeRef {
-                                    unpack,
-                                    value: &node.value,
+                                    assignment,
+                                    target_index,
                                     name: name_node,
-                                    first,
+                                    kind,
                                 },
                             );
                         }
@@ -1080,25 +1033,14 @@ where
                     }
                 }
 
-                if let Some(CurrentAssignment::Assign { first, .. }) = self.current_assignment_mut()
-                {
-                    *first = false;
-                }
-
                 walk_expr(self, expr);
             }
             ast::Expr::Named(node) => {
                 // TODO walrus in comprehensions is implicitly nonlocal
                 self.visit_expr(&node.value);
-
-                // See https://peps.python.org/pep-0572/#differences-between-assignment-expressions-and-assignment-statements
-                if node.target.is_name_expr() {
-                    self.push_assignment(node.into());
-                    self.visit_expr(&node.target);
-                    self.pop_assignment();
-                } else {
-                    self.visit_expr(&node.target);
-                }
+                self.push_assignment(node.into());
+                self.visit_expr(&node.target);
+                self.pop_assignment();
             }
             ast::Expr::Lambda(lambda) => {
                 if let Some(parameters) = &lambda.parameters {
@@ -1131,13 +1073,10 @@ where
                 // AST inspection, so we can't simplify here, need to record test expression for
                 // later checking)
                 self.visit_expr(test);
-                let constraint = self.record_expression_constraint(test);
                 let pre_if = self.flow_snapshot();
                 self.visit_expr(body);
                 let post_body = self.flow_snapshot();
                 self.flow_restore(pre_if);
-
-                self.record_negated_constraint(constraint);
                 self.visit_expr(orelse);
                 self.flow_merge(post_body);
             }
@@ -1290,9 +1229,9 @@ where
 #[derive(Copy, Clone, Debug, PartialEq)]
 enum CurrentAssignment<'a> {
     Assign {
-        node: &'a ast::StmtAssign,
-        first: bool,
-        unpack: Option<Unpack<'a>>,
+        assignment: &'a ast::StmtAssign,
+        target_index: usize,
+        kind: AssignmentKind,
     },
     AnnAssign(&'a ast::StmtAnnAssign),
     AugAssign(&'a ast::StmtAugAssign),

crates/red_knot_python_semantic/src/semantic_index/definition.rs

@@ -6,22 +6,8 @@ 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::unpack::Unpack;
 use crate::Db;
 
-/// A definition of a symbol.
-///
-/// ## Module-local type
-/// This type should not be used as part of any cross-module API because
-/// it holds a reference to the AST node. Range-offset changes
-/// then propagate through all usages, and deserialization requires
-/// reparsing the entire module.
-///
-/// E.g. don't use this type in:
-///
-/// * a return type of a cross-module query
-/// * a field of a type that is a return type of a cross-module query
-/// * an argument of a cross-module query
 #[salsa::tracked]
 pub struct Definition<'db> {
     /// The file in which the definition occurs.
@@ -38,7 +24,7 @@ pub struct Definition<'db> {
 
     #[no_eq]
     #[return_ref]
-    pub(crate) kind: DefinitionKind<'db>,
+    pub(crate) kind: DefinitionKind,
 
     #[no_eq]
     count: countme::Count<Definition<'static>>,
@@ -92,9 +78,6 @@ pub(crate) enum DefinitionNodeRef<'a> {
     WithItem(WithItemDefinitionNodeRef<'a>),
     MatchPattern(MatchPatternDefinitionNodeRef<'a>),
     ExceptHandler(ExceptHandlerDefinitionNodeRef<'a>),
-    TypeVar(&'a ast::TypeParamTypeVar),
-    ParamSpec(&'a ast::TypeParamParamSpec),
-    TypeVarTuple(&'a ast::TypeParamTypeVarTuple),
 }
 
 impl<'a> From<&'a ast::StmtFunctionDef> for DefinitionNodeRef<'a> {
@@ -133,24 +116,6 @@ impl<'a> From<&'a ast::Alias> for DefinitionNodeRef<'a> {
     }
 }
 
-impl<'a> From<&'a ast::TypeParamTypeVar> for DefinitionNodeRef<'a> {
-    fn from(value: &'a ast::TypeParamTypeVar) -> Self {
-        Self::TypeVar(value)
-    }
-}
-
-impl<'a> From<&'a ast::TypeParamParamSpec> for DefinitionNodeRef<'a> {
-    fn from(value: &'a ast::TypeParamParamSpec) -> Self {
-        Self::ParamSpec(value)
-    }
-}
-
-impl<'a> From<&'a ast::TypeParamTypeVarTuple> for DefinitionNodeRef<'a> {
-    fn from(value: &'a ast::TypeParamTypeVarTuple) -> Self {
-        Self::TypeVarTuple(value)
-    }
-}
-
 impl<'a> From<ImportFromDefinitionNodeRef<'a>> for DefinitionNodeRef<'a> {
     fn from(node_ref: ImportFromDefinitionNodeRef<'a>) -> Self {
         Self::ImportFrom(node_ref)
@@ -201,10 +166,10 @@ pub(crate) struct ImportFromDefinitionNodeRef<'a> {
 
 #[derive(Copy, Clone, Debug)]
 pub(crate) struct AssignmentDefinitionNodeRef<'a> {
-    pub(crate) unpack: Option<Unpack<'a>>,
-    pub(crate) value: &'a ast::Expr,
+    pub(crate) assignment: &'a ast::StmtAssign,
+    pub(crate) target_index: usize,
     pub(crate) name: &'a ast::ExprName,
-    pub(crate) first: bool,
+    pub(crate) kind: AssignmentKind,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -246,9 +211,9 @@ pub(crate) struct MatchPatternDefinitionNodeRef<'a> {
     pub(crate) index: u32,
 }
 
-impl<'db> DefinitionNodeRef<'db> {
+impl DefinitionNodeRef<'_> {
     #[allow(unsafe_code)]
-    pub(super) unsafe fn into_owned(self, parsed: ParsedModule) -> DefinitionKind<'db> {
+    pub(super) unsafe fn into_owned(self, parsed: ParsedModule) -> DefinitionKind {
         match self {
             DefinitionNodeRef::Import(alias) => {
                 DefinitionKind::Import(AstNodeRef::new(parsed, alias))
@@ -269,15 +234,15 @@ impl<'db> DefinitionNodeRef<'db> {
                 DefinitionKind::NamedExpression(AstNodeRef::new(parsed, named))
             }
             DefinitionNodeRef::Assignment(AssignmentDefinitionNodeRef {
-                unpack,
-                value,
+                assignment,
+                target_index,
                 name,
-                first,
+                kind,
             }) => DefinitionKind::Assignment(AssignmentDefinitionKind {
-                target: TargetKind::from(unpack),
-                value: AstNodeRef::new(parsed.clone(), value),
+                assignment: AstNodeRef::new(parsed.clone(), assignment),
+                target_index,
                 name: AstNodeRef::new(parsed, name),
-                first,
+                kind,
             }),
             DefinitionNodeRef::AnnotatedAssignment(assign) => {
                 DefinitionKind::AnnotatedAssignment(AstNodeRef::new(parsed, assign))
@@ -338,15 +303,6 @@ impl<'db> DefinitionNodeRef<'db> {
                 handler: AstNodeRef::new(parsed, handler),
                 is_star,
             }),
-            DefinitionNodeRef::TypeVar(node) => {
-                DefinitionKind::TypeVar(AstNodeRef::new(parsed, node))
-            }
-            DefinitionNodeRef::ParamSpec(node) => {
-                DefinitionKind::ParamSpec(AstNodeRef::new(parsed, node))
-            }
-            DefinitionNodeRef::TypeVarTuple(node) => {
-                DefinitionKind::TypeVarTuple(AstNodeRef::new(parsed, node))
-            }
         }
     }
 
@@ -360,10 +316,10 @@ impl<'db> DefinitionNodeRef<'db> {
             Self::Class(node) => node.into(),
             Self::NamedExpression(node) => node.into(),
             Self::Assignment(AssignmentDefinitionNodeRef {
-                value: _,
-                unpack: _,
+                assignment: _,
+                target_index: _,
                 name,
-                first: _,
+                kind: _,
             }) => name.into(),
             Self::AnnotatedAssignment(node) => node.into(),
             Self::AugmentedAssignment(node) => node.into(),
@@ -386,9 +342,6 @@ impl<'db> DefinitionNodeRef<'db> {
                 identifier.into()
             }
             Self::ExceptHandler(ExceptHandlerDefinitionNodeRef { handler, .. }) => handler.into(),
-            Self::TypeVar(node) => node.into(),
-            Self::ParamSpec(node) => node.into(),
-            Self::TypeVarTuple(node) => node.into(),
         }
     }
 }
@@ -429,13 +382,13 @@ impl DefinitionCategory {
 }
 
 #[derive(Clone, Debug)]
-pub enum DefinitionKind<'db> {
+pub enum DefinitionKind {
     Import(AstNodeRef<ast::Alias>),
     ImportFrom(ImportFromDefinitionKind),
     Function(AstNodeRef<ast::StmtFunctionDef>),
     Class(AstNodeRef<ast::StmtClassDef>),
     NamedExpression(AstNodeRef<ast::ExprNamed>),
-    Assignment(AssignmentDefinitionKind<'db>),
+    Assignment(AssignmentDefinitionKind),
     AnnotatedAssignment(AstNodeRef<ast::StmtAnnAssign>),
     AugmentedAssignment(AstNodeRef<ast::StmtAugAssign>),
     For(ForStmtDefinitionKind),
@@ -445,22 +398,16 @@ pub enum DefinitionKind<'db> {
     WithItem(WithItemDefinitionKind),
     MatchPattern(MatchPatternDefinitionKind),
     ExceptHandler(ExceptHandlerDefinitionKind),
-    TypeVar(AstNodeRef<ast::TypeParamTypeVar>),
-    ParamSpec(AstNodeRef<ast::TypeParamParamSpec>),
-    TypeVarTuple(AstNodeRef<ast::TypeParamTypeVarTuple>),
 }
 
-impl DefinitionKind<'_> {
+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(_)
-            | DefinitionKind::TypeVar(_)
-            | DefinitionKind::ParamSpec(_)
-            | DefinitionKind::TypeVarTuple(_) => DefinitionCategory::DeclarationAndBinding,
+            | 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() {
@@ -498,21 +445,6 @@ impl DefinitionKind<'_> {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
-pub(crate) enum TargetKind<'db> {
-    Sequence(Unpack<'db>),
-    Name,
-}
-
-impl<'db> From<Option<Unpack<'db>>> for TargetKind<'db> {
-    fn from(value: Option<Unpack<'db>>) -> Self {
-        match value {
-            Some(unpack) => TargetKind::Sequence(unpack),
-            None => TargetKind::Name,
-        }
-    }
-}
-
 #[derive(Clone, Debug)]
 #[allow(dead_code)]
 pub struct MatchPatternDefinitionKind {
@@ -574,31 +506,38 @@ impl ImportFromDefinitionKind {
 }
 
 #[derive(Clone, Debug)]
-pub struct AssignmentDefinitionKind<'db> {
-    target: TargetKind<'db>,
-    value: AstNodeRef<ast::Expr>,
+pub struct AssignmentDefinitionKind {
+    assignment: AstNodeRef<ast::StmtAssign>,
+    target_index: usize,
     name: AstNodeRef<ast::ExprName>,
-    first: bool,
+    kind: AssignmentKind,
 }
 
-impl<'db> AssignmentDefinitionKind<'db> {
-    pub(crate) fn target(&self) -> TargetKind<'db> {
-        self.target
+impl AssignmentDefinitionKind {
+    pub(crate) fn value(&self) -> &ast::Expr {
+        &self.assignment.node().value
     }
 
-    pub(crate) fn value(&self) -> &ast::Expr {
-        self.value.node()
+    pub(crate) fn target(&self) -> &ast::Expr {
+        &self.assignment.node().targets[self.target_index]
     }
 
     pub(crate) fn name(&self) -> &ast::ExprName {
         self.name.node()
     }
 
-    pub(crate) fn is_first(&self) -> bool {
-        self.first
+    pub(crate) fn kind(&self) -> AssignmentKind {
+        self.kind
     }
 }
 
+/// The kind of assignment target expression.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum AssignmentKind {
+    Sequence,
+    Name,
+}
+
 #[derive(Clone, Debug)]
 pub struct WithItemDefinitionKind {
     node: AstNodeRef<ast::WithItem>,
@@ -735,21 +674,3 @@ impl From<&ast::ExceptHandlerExceptHandler> for DefinitionNodeKey {
         Self(NodeKey::from_node(handler))
     }
 }
-
-impl From<&ast::TypeParamTypeVar> for DefinitionNodeKey {
-    fn from(value: &ast::TypeParamTypeVar) -> Self {
-        Self(NodeKey::from_node(value))
-    }
-}
-
-impl From<&ast::TypeParamParamSpec> for DefinitionNodeKey {
-    fn from(value: &ast::TypeParamParamSpec) -> Self {
-        Self(NodeKey::from_node(value))
-    }
-}
-
-impl From<&ast::TypeParamTypeVarTuple> for DefinitionNodeKey {
-    fn from(value: &ast::TypeParamTypeVarTuple) -> Self {
-        Self(NodeKey::from_node(value))
-    }
-}

crates/red_knot_python_semantic/src/semantic_index/expression.rs

@@ -8,18 +8,6 @@ use salsa;
 /// An independently type-inferable expression.
 ///
 /// Includes constraint expressions (e.g. if tests) and the RHS of an unpacking assignment.
-///
-/// ## Module-local type
-/// This type should not be used as part of any cross-module API because
-/// it holds a reference to the AST node. Range-offset changes
-/// then propagate through all usages, and deserialization requires
-/// reparsing the entire module.
-///
-/// E.g. don't use this type in:
-///
-/// * a return type of a cross-module query
-/// * a field of a type that is a return type of a cross-module query
-/// * an argument of a cross-module query
 #[salsa::tracked]
 pub(crate) struct Expression<'db> {
     /// The file in which the expression occurs.

crates/red_knot_python_semantic/src/semantic_index/symbol.rs

@@ -103,10 +103,14 @@ pub struct ScopedSymbolId;
 pub struct ScopeId<'db> {
     #[id]
     pub file: File,
-
     #[id]
     pub file_scope_id: FileScopeId,
 
+    /// The node that introduces this scope.
+    #[no_eq]
+    #[return_ref]
+    pub node: NodeWithScopeKind,
+
     #[no_eq]
     count: countme::Count<ScopeId<'static>>,
 }
@@ -127,14 +131,6 @@ impl<'db> ScopeId<'db> {
         )
     }
 
-    pub(crate) fn node(self, db: &dyn Db) -> &NodeWithScopeKind {
-        self.scope(db).node()
-    }
-
-    pub(crate) fn scope(self, db: &dyn Db) -> &Scope {
-        semantic_index(db, self.file(db)).scope(self.file_scope_id(db))
-    }
-
     #[cfg(test)]
     pub(crate) fn name(self, db: &'db dyn Db) -> &'db str {
         match self.node(db) {
@@ -173,10 +169,10 @@ impl FileScopeId {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Eq, PartialEq)]
 pub struct Scope {
     pub(super) parent: Option<FileScopeId>,
-    pub(super) node: NodeWithScopeKind,
+    pub(super) kind: ScopeKind,
     pub(super) descendents: Range<FileScopeId>,
 }
 
@@ -185,12 +181,8 @@ impl Scope {
         self.parent
     }
 
-    pub fn node(&self) -> &NodeWithScopeKind {
-        &self.node
-    }
-
     pub fn kind(&self) -> ScopeKind {
-        self.node().scope_kind()
+        self.kind
     }
 }
 
@@ -210,7 +202,7 @@ impl ScopeKind {
 }
 
 /// Symbol table for a specific [`Scope`].
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct SymbolTable {
     /// The symbols in this scope.
     symbols: IndexVec<ScopedSymbolId, Symbol>,
@@ -220,6 +212,13 @@ pub struct SymbolTable {
 }
 
 impl SymbolTable {
+    fn new() -> Self {
+        Self {
+            symbols: IndexVec::new(),
+            symbols_by_name: SymbolMap::default(),
+        }
+    }
+
     fn shrink_to_fit(&mut self) {
         self.symbols.shrink_to_fit();
     }
@@ -271,12 +270,18 @@ impl PartialEq for SymbolTable {
 
 impl Eq for SymbolTable {}
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub(super) struct SymbolTableBuilder {
     table: SymbolTable,
 }
 
 impl SymbolTableBuilder {
+    pub(super) fn new() -> Self {
+        Self {
+            table: SymbolTable::new(),
+        }
+    }
+
     pub(super) fn add_symbol(&mut self, name: Name) -> (ScopedSymbolId, bool) {
         let hash = SymbolTable::hash_name(&name);
         let entry = self
@@ -371,6 +376,21 @@ impl NodeWithScopeRef<'_> {
         }
     }
 
+    pub(super) fn scope_kind(self) -> ScopeKind {
+        match self {
+            NodeWithScopeRef::Module => ScopeKind::Module,
+            NodeWithScopeRef::Class(_) => ScopeKind::Class,
+            NodeWithScopeRef::Function(_) => ScopeKind::Function,
+            NodeWithScopeRef::Lambda(_) => ScopeKind::Function,
+            NodeWithScopeRef::FunctionTypeParameters(_)
+            | NodeWithScopeRef::ClassTypeParameters(_) => ScopeKind::Annotation,
+            NodeWithScopeRef::ListComprehension(_)
+            | NodeWithScopeRef::SetComprehension(_)
+            | NodeWithScopeRef::DictComprehension(_)
+            | NodeWithScopeRef::GeneratorExpression(_) => ScopeKind::Comprehension,
+        }
+    }
+
     pub(crate) fn node_key(self) -> NodeWithScopeKey {
         match self {
             NodeWithScopeRef::Module => NodeWithScopeKey::Module,
@@ -418,36 +438,6 @@ pub enum NodeWithScopeKind {
     GeneratorExpression(AstNodeRef<ast::ExprGenerator>),
 }
 
-impl NodeWithScopeKind {
-    pub(super) const fn scope_kind(&self) -> ScopeKind {
-        match self {
-            Self::Module => ScopeKind::Module,
-            Self::Class(_) => ScopeKind::Class,
-            Self::Function(_) => ScopeKind::Function,
-            Self::Lambda(_) => ScopeKind::Function,
-            Self::FunctionTypeParameters(_) | Self::ClassTypeParameters(_) => ScopeKind::Annotation,
-            Self::ListComprehension(_)
-            | Self::SetComprehension(_)
-            | Self::DictComprehension(_)
-            | Self::GeneratorExpression(_) => ScopeKind::Comprehension,
-        }
-    }
-
-    pub fn expect_class(&self) -> &ast::StmtClassDef {
-        match self {
-            Self::Class(class) => class.node(),
-            _ => panic!("expected class"),
-        }
-    }
-
-    pub fn expect_function(&self) -> &ast::StmtFunctionDef {
-        match self {
-            Self::Function(function) => function.node(),
-            _ => panic!("expected function"),
-        }
-    }
-}
-
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
 pub(crate) enum NodeWithScopeKey {
     Module,

crates/red_knot_python_semantic/src/semantic_index/use_def.rs

@@ -277,7 +277,7 @@ impl<'db> UseDefMap<'db> {
 
     pub(crate) fn use_boundness(&self, use_id: ScopedUseId) -> Boundness {
         if self.bindings_by_use[use_id].may_be_unbound() {
-            Boundness::PossiblyUnbound
+            Boundness::MayBeUnbound
         } else {
             Boundness::Bound
         }
@@ -292,7 +292,7 @@ impl<'db> UseDefMap<'db> {
 
     pub(crate) fn public_boundness(&self, symbol: ScopedSymbolId) -> Boundness {
         if self.public_symbols[symbol].may_be_unbound() {
-            Boundness::PossiblyUnbound
+            Boundness::MayBeUnbound
         } else {
             Boundness::Bound
         }
@@ -459,6 +459,10 @@ pub(super) struct UseDefMapBuilder<'db> {
 }
 
 impl<'db> UseDefMapBuilder<'db> {
+    pub(super) fn new() -> Self {
+        Self::default()
+    }
+
     pub(super) fn add_symbol(&mut self, symbol: ScopedSymbolId) {
         let new_symbol = self.symbol_states.push(SymbolState::undefined());
         debug_assert_eq!(symbol, new_symbol);

crates/red_knot_python_semantic/src/semantic_model.rs

@@ -6,7 +6,7 @@ use ruff_source_file::LineIndex;
 
 use crate::module_name::ModuleName;
 use crate::module_resolver::{resolve_module, Module};
-use crate::semantic_index::ast_ids::HasScopedExpressionId;
+use crate::semantic_index::ast_ids::HasScopedAstId;
 use crate::semantic_index::semantic_index;
 use crate::types::{binding_ty, infer_scope_types, Type};
 use crate::Db;
@@ -54,7 +54,7 @@ impl HasTy for ast::ExpressionRef<'_> {
         let file_scope = index.expression_scope_id(*self);
         let scope = file_scope.to_scope_id(model.db, model.file);
 
-        let expression_id = self.scoped_expression_id(model.db, scope);
+        let expression_id = self.scoped_ast_id(model.db, scope);
         infer_scope_types(model.db, scope).expression_ty(expression_id)
     }
 }

crates/red_knot_python_semantic/src/site_packages.rs

@@ -732,20 +732,7 @@ mod tests {
         let system = TestSystem::default();
         assert!(matches!(
             VirtualEnvironment::new("/.venv", &system),
-            Err(SitePackagesDiscoveryError::VenvDirCanonicalizationError(..))
-        ));
-    }
-
-    #[test]
-    fn reject_venv_that_is_not_a_directory() {
-        let system = TestSystem::default();
-        system
-            .memory_file_system()
-            .write_file("/.venv", "")
-            .unwrap();
-        assert!(matches!(
-            VirtualEnvironment::new("/.venv", &system),
-            Err(SitePackagesDiscoveryError::VenvDirIsNotADirectory(..))
+            Err(SitePackagesDiscoveryError::VenvDirIsNotADirectory(_))
         ));
     }
 

crates/red_knot_python_semantic/src/stdlib.rs

@@ -8,38 +8,34 @@ use crate::Db;
 
 /// Enumeration of various core stdlib modules, for which we have dedicated Salsa queries.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) enum CoreStdlibModule {
+enum CoreStdlibModule {
     Builtins,
     Types,
+    // the Typing enum is currently only used in tests
+    #[allow(dead_code)]
+    Typing,
     Typeshed,
     TypingExtensions,
-    Typing,
-    Sys,
 }
 
 impl CoreStdlibModule {
-    pub(crate) const fn as_str(self) -> &'static str {
-        match self {
+    fn name(self) -> ModuleName {
+        let module_name = match self {
             Self::Builtins => "builtins",
             Self::Types => "types",
             Self::Typing => "typing",
             Self::Typeshed => "_typeshed",
             Self::TypingExtensions => "typing_extensions",
-            Self::Sys => "sys",
-        }
-    }
-
-    pub(crate) fn name(self) -> ModuleName {
-        let self_as_str = self.as_str();
-        ModuleName::new_static(self_as_str)
-            .unwrap_or_else(|| panic!("{self_as_str} should be a valid module name!"))
+        };
+        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 `Symbol::Unbound` if the given core module cannot be resolved for some reason
-pub(crate) fn core_module_symbol<'db>(
+fn core_module_symbol<'db>(
     db: &'db dyn Db,
     core_module: CoreStdlibModule,
     symbol: &str,
@@ -57,14 +53,29 @@ pub(crate) fn builtins_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db>
     core_module_symbol(db, CoreStdlibModule::Builtins, symbol)
 }
 
+/// Lookup the type of `symbol` in the `types` module namespace.
+///
+/// Returns `Symbol::Unbound` if the `types` module isn't available for some reason.
+#[inline]
+pub(crate) fn types_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
+    core_module_symbol(db, CoreStdlibModule::Types, symbol)
+}
+
 /// Lookup the type of `symbol` in the `typing` module namespace.
 ///
 /// Returns `Symbol::Unbound` if the `typing` module isn't available for some reason.
 #[inline]
-#[cfg(test)]
+#[allow(dead_code)] // currently only used in tests
 pub(crate) fn typing_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
     core_module_symbol(db, CoreStdlibModule::Typing, symbol)
 }
+/// Lookup the type of `symbol` in the `_typeshed` module namespace.
+///
+/// Returns `Symbol::Unbound` if the `_typeshed` module isn't available for some reason.
+#[inline]
+pub(crate) fn typeshed_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
+    core_module_symbol(db, CoreStdlibModule::Typeshed, symbol)
+}
 
 /// Lookup the type of `symbol` in the `typing_extensions` module namespace.
 ///

crates/red_knot_python_semantic/src/symbol.rs

@@ -3,19 +3,10 @@ use crate::{
     Db,
 };
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub(crate) enum Boundness {
     Bound,
-    PossiblyUnbound,
-}
-
-impl Boundness {
-    pub(crate) fn or(self, other: Boundness) -> Boundness {
-        match (self, other) {
-            (Boundness::Bound, _) | (_, Boundness::Bound) => Boundness::Bound,
-            (Boundness::PossiblyUnbound, Boundness::PossiblyUnbound) => Boundness::PossiblyUnbound,
-        }
-    }
+    MayBeUnbound,
 }
 
 /// The result of a symbol lookup, which can either be a (possibly unbound) type
@@ -26,14 +17,14 @@ impl Boundness {
 /// bound = 1
 ///
 /// if flag:
-///     possibly_unbound = 2
+///     maybe_unbound = 2
 /// ```
 ///
 /// If we look up symbols in this scope, we would get the following results:
 /// ```rs
-/// bound:             Symbol::Type(Type::IntLiteral(1), Boundness::Bound),
-/// possibly_unbound:  Symbol::Type(Type::IntLiteral(2), Boundness::PossiblyUnbound),
-/// non_existent:      Symbol::Unbound,
+/// bound:          Symbol::Type(Type::IntLiteral(1), Boundness::Bound),
+/// maybe_unbound:  Symbol::Type(Type::IntLiteral(2), Boundness::MayBeUnbound),
+/// non_existent:   Symbol::Unbound,
 /// ```
 #[derive(Debug, Clone, PartialEq)]
 pub(crate) enum Symbol<'db> {
@@ -46,18 +37,25 @@ impl<'db> Symbol<'db> {
         matches!(self, Symbol::Unbound)
     }
 
-    pub(crate) fn possibly_unbound(&self) -> bool {
+    pub(crate) fn may_be_unbound(&self) -> bool {
         match self {
-            Symbol::Type(_, Boundness::PossiblyUnbound) | Symbol::Unbound => true,
+            Symbol::Type(_, Boundness::MayBeUnbound) | Symbol::Unbound => true,
             Symbol::Type(_, Boundness::Bound) => false,
         }
     }
 
-    /// Returns the type of the symbol, ignoring possible unboundness.
-    ///
-    /// If the symbol is *definitely* unbound, this function will return `None`. Otherwise,
-    /// if there is at least one control-flow path where the symbol is bound, return the type.
-    pub(crate) fn ignore_possibly_unbound(&self) -> Option<Type<'db>> {
+    pub(crate) fn unwrap_or(&self, other: Type<'db>) -> Type<'db> {
+        match self {
+            Symbol::Type(ty, _) => *ty,
+            Symbol::Unbound => other,
+        }
+    }
+
+    pub(crate) fn unwrap_or_unknown(&self) -> Type<'db> {
+        self.unwrap_or(Type::Unknown)
+    }
+
+    pub(crate) fn as_type(&self) -> Option<Type<'db>> {
         match self {
             Symbol::Type(ty, _) => Some(*ty),
             Symbol::Unbound => None,
@@ -67,80 +65,28 @@ impl<'db> Symbol<'db> {
     #[cfg(test)]
     #[track_caller]
     pub(crate) fn expect_type(self) -> Type<'db> {
-        self.ignore_possibly_unbound()
+        self.as_type()
             .expect("Expected a (possibly unbound) type, not an unbound symbol")
     }
 
     #[must_use]
-    pub(crate) fn or_fall_back_to(self, db: &'db dyn Db, fallback: &Symbol<'db>) -> Symbol<'db> {
-        match fallback {
-            Symbol::Type(fallback_ty, fallback_boundness) => match self {
-                Symbol::Type(_, Boundness::Bound) => self,
-                Symbol::Type(ty, boundness @ Boundness::PossiblyUnbound) => Symbol::Type(
-                    UnionType::from_elements(db, [*fallback_ty, ty]),
-                    fallback_boundness.or(boundness),
-                ),
-                Symbol::Unbound => fallback.clone(),
-            },
+    pub(crate) fn replace_unbound_with(
+        self,
+        db: &'db dyn Db,
+        replacement: &Symbol<'db>,
+    ) -> Symbol<'db> {
+        match replacement {
+            Symbol::Type(replacement, _) => Symbol::Type(
+                match self {
+                    Symbol::Type(ty, Boundness::Bound) => ty,
+                    Symbol::Type(ty, Boundness::MayBeUnbound) => {
+                        UnionType::from_elements(db, [*replacement, ty])
+                    }
+                    Symbol::Unbound => *replacement,
+                },
+                Boundness::Bound,
+            ),
             Symbol::Unbound => self,
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::types::tests::setup_db;
-
-    #[test]
-    fn test_symbol_or_fall_back_to() {
-        use Boundness::{Bound, PossiblyUnbound};
-
-        let db = setup_db();
-        let ty1 = Type::IntLiteral(1);
-        let ty2 = Type::IntLiteral(2);
-
-        // Start from an unbound symbol
-        assert_eq!(
-            Symbol::Unbound.or_fall_back_to(&db, &Symbol::Unbound),
-            Symbol::Unbound
-        );
-        assert_eq!(
-            Symbol::Unbound.or_fall_back_to(&db, &Symbol::Type(ty1, PossiblyUnbound)),
-            Symbol::Type(ty1, PossiblyUnbound)
-        );
-        assert_eq!(
-            Symbol::Unbound.or_fall_back_to(&db, &Symbol::Type(ty1, Bound)),
-            Symbol::Type(ty1, Bound)
-        );
-
-        // Start from a possibly unbound symbol
-        assert_eq!(
-            Symbol::Type(ty1, PossiblyUnbound).or_fall_back_to(&db, &Symbol::Unbound),
-            Symbol::Type(ty1, PossiblyUnbound)
-        );
-        assert_eq!(
-            Symbol::Type(ty1, PossiblyUnbound)
-                .or_fall_back_to(&db, &Symbol::Type(ty2, PossiblyUnbound)),
-            Symbol::Type(UnionType::from_elements(&db, [ty2, ty1]), PossiblyUnbound)
-        );
-        assert_eq!(
-            Symbol::Type(ty1, PossiblyUnbound).or_fall_back_to(&db, &Symbol::Type(ty2, Bound)),
-            Symbol::Type(UnionType::from_elements(&db, [ty2, ty1]), Bound)
-        );
-
-        // Start from a definitely bound symbol
-        assert_eq!(
-            Symbol::Type(ty1, Bound).or_fall_back_to(&db, &Symbol::Unbound),
-            Symbol::Type(ty1, Bound)
-        );
-        assert_eq!(
-            Symbol::Type(ty1, Bound).or_fall_back_to(&db, &Symbol::Type(ty2, PossiblyUnbound)),
-            Symbol::Type(ty1, Bound)
-        );
-        assert_eq!(
-            Symbol::Type(ty1, Bound).or_fall_back_to(&db, &Symbol::Type(ty2, Bound)),
-            Symbol::Type(ty1, Bound)
-        );
-    }
-}

crates/red_knot_python_semantic/src/types/builder.rs

@@ -25,11 +25,12 @@
 //!   * 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::{InstanceType, IntersectionType, KnownClass, Type, UnionType};
+use crate::types::{IntersectionType, Type, UnionType};
 use crate::{Db, FxOrderSet};
 use smallvec::SmallVec;
 
+use super::KnownClass;
+
 pub(crate) struct UnionBuilder<'db> {
     elements: Vec<Type<'db>>,
     db: &'db dyn Db,
@@ -79,6 +80,7 @@ impl<'db> UnionBuilder<'db> {
                         to_remove.push(index);
                     }
                 }
+
                 match to_remove[..] {
                     [] => self.elements.push(to_add),
                     [index] => self.elements[index] = to_add,
@@ -101,6 +103,7 @@ impl<'db> UnionBuilder<'db> {
                 }
             }
         }
+
         self
     }
 
@@ -128,7 +131,7 @@ impl<'db> IntersectionBuilder<'db> {
     pub(crate) fn new(db: &'db dyn Db) -> Self {
         Self {
             db,
-            intersections: vec![InnerIntersectionBuilder::default()],
+            intersections: vec![InnerIntersectionBuilder::new()],
         }
     }
 
@@ -231,6 +234,10 @@ struct InnerIntersectionBuilder<'db> {
 }
 
 impl<'db> InnerIntersectionBuilder<'db> {
+    fn new() -> Self {
+        Self::default()
+    }
+
     /// Adds a positive type to this intersection.
     fn add_positive(&mut self, db: &'db dyn Db, new_positive: Type<'db>) {
         if let Type::Intersection(other) = new_positive {
@@ -242,14 +249,14 @@ impl<'db> InnerIntersectionBuilder<'db> {
             }
         } else {
             // ~Literal[True] & bool = Literal[False]
-            if let Type::Instance(InstanceType { class }) = new_positive {
-                if class.is_known(db, KnownClass::Bool) {
+            if let Type::Instance(class_type) = new_positive {
+                if class_type.is_known(db, KnownClass::Bool) {
                     if let Some(&Type::BooleanLiteral(value)) = self
                         .negative
                         .iter()
                         .find(|element| element.is_boolean_literal())
                     {
-                        *self = Self::default();
+                        *self = Self::new();
                         self.positive.insert(Type::BooleanLiteral(!value));
                         return;
                     }
@@ -268,7 +275,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
                 }
                 // A & B = Never    if A and B are disjoint
                 if new_positive.is_disjoint_from(db, *existing_positive) {
-                    *self = Self::default();
+                    *self = Self::new();
                     self.positive.insert(Type::Never);
                     return;
                 }
@@ -281,7 +288,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
             for (index, existing_negative) in self.negative.iter().enumerate() {
                 // S & ~T = Never    if S <: T
                 if new_positive.is_subtype_of(db, *existing_negative) {
-                    *self = Self::default();
+                    *self = Self::new();
                     self.positive.insert(Type::Never);
                     return;
                 }
@@ -313,7 +320,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
                 // Adding any of these types to the negative side of an intersection
                 // is equivalent to adding it to the positive side. We do this to
                 // simplify the representation.
-                self.add_positive(db, ty);
+                self.positive.insert(ty);
             }
             // ~Literal[True] & bool = Literal[False]
             Type::BooleanLiteral(bool)
@@ -322,7 +329,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
                     .iter()
                     .any(|pos| *pos == KnownClass::Bool.to_instance(db)) =>
             {
-                *self = Self::default();
+                *self = Self::new();
                 self.positive.insert(Type::BooleanLiteral(!bool));
             }
             _ => {
@@ -344,7 +351,7 @@ impl<'db> InnerIntersectionBuilder<'db> {
                 for existing_positive in &self.positive {
                     // S & ~T = Never    if S <: T
                     if existing_positive.is_subtype_of(db, new_negative) {
-                        *self = Self::default();
+                        *self = Self::new();
                         self.positive.insert(Type::Never);
                         return;
                     }
@@ -379,9 +386,8 @@ mod tests {
     use crate::program::{Program, SearchPathSettings};
     use crate::python_version::PythonVersion;
     use crate::stdlib::typing_symbol;
-    use crate::types::{global_symbol, KnownClass, UnionBuilder};
+    use crate::types::{KnownClass, StringLiteralType, UnionBuilder};
     use crate::ProgramSettings;
-    use ruff_db::files::system_path_to_file;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
     use test_case::test_case;
 
@@ -588,22 +594,6 @@ mod tests {
         assert_eq!(ta_not_i0.display(&db).to_string(), "int & Any | Literal[1]");
     }
 
-    #[test]
-    fn build_intersection_simplify_negative_any() {
-        let db = setup_db();
-
-        let ty = IntersectionBuilder::new(&db)
-            .add_negative(Type::Any)
-            .build();
-        assert_eq!(ty, Type::Any);
-
-        let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::Never)
-            .add_negative(Type::Any)
-            .build();
-        assert_eq!(ty, Type::Never);
-    }
-
     #[test]
     fn intersection_distributes_over_union() {
         let db = setup_db();
@@ -685,8 +675,8 @@ mod tests {
     fn build_intersection_self_negation() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
-            .add_negative(Type::none(&db))
+            .add_positive(Type::None)
+            .add_negative(Type::None)
             .build();
 
         assert_eq!(ty, Type::Never);
@@ -696,18 +686,18 @@ mod tests {
     fn build_intersection_simplify_negative_never() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
+            .add_positive(Type::None)
             .add_negative(Type::Never)
             .build();
 
-        assert_eq!(ty, Type::none(&db));
+        assert_eq!(ty, Type::None);
     }
 
     #[test]
     fn build_intersection_simplify_positive_never() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
+            .add_positive(Type::None)
             .add_positive(Type::Never)
             .build();
 
@@ -719,14 +709,14 @@ mod tests {
         let db = setup_db();
 
         let ty = IntersectionBuilder::new(&db)
-            .add_negative(Type::none(&db))
+            .add_negative(Type::None)
             .add_positive(Type::IntLiteral(1))
             .build();
         assert_eq!(ty, Type::IntLiteral(1));
 
         let ty = IntersectionBuilder::new(&db)
             .add_positive(Type::IntLiteral(1))
-            .add_negative(Type::none(&db))
+            .add_negative(Type::None)
             .build();
         assert_eq!(ty, Type::IntLiteral(1));
     }
@@ -771,7 +761,7 @@ mod tests {
             .build();
         assert_eq!(ty, s);
 
-        let literal = Type::string_literal(&db, "a");
+        let literal = Type::StringLiteral(StringLiteralType::new(&db, "a"));
         let expected = IntersectionBuilder::new(&db)
             .add_positive(s)
             .add_negative(literal)
@@ -874,7 +864,7 @@ mod tests {
 
         let ty = IntersectionBuilder::new(&db)
             .add_positive(s)
-            .add_negative(Type::string_literal(&db, "a"))
+            .add_negative(Type::StringLiteral(StringLiteralType::new(&db, "a")))
             .add_negative(t)
             .build();
         assert_eq!(ty, Type::Never);
@@ -885,7 +875,7 @@ mod tests {
         let db = setup_db();
 
         let t1 = Type::IntLiteral(1);
-        let t2 = Type::none(&db);
+        let t2 = Type::None;
 
         let ty = IntersectionBuilder::new(&db)
             .add_positive(t1)
@@ -908,7 +898,7 @@ mod tests {
         let db = setup_db();
 
         let t_p = KnownClass::Int.to_instance(&db);
-        let t_n = Type::string_literal(&db, "t_n");
+        let t_n = Type::StringLiteral(StringLiteralType::new(&db, "t_n"));
 
         let ty = IntersectionBuilder::new(&db)
             .add_positive(t_p)
@@ -1003,66 +993,4 @@ mod tests {
             .build();
         assert_eq!(result, ty);
     }
-
-    #[test]
-    fn build_intersection_of_two_unions_simplify() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/module.py",
-            "
-            class A: ...
-            class B: ...
-            a = A()
-            b = B()
-        ",
-        )
-        .unwrap();
-
-        let file = system_path_to_file(&db, "src/module.py").expect("file to exist");
-
-        let a = global_symbol(&db, file, "a").expect_type();
-        let b = global_symbol(&db, file, "b").expect_type();
-        let union = UnionBuilder::new(&db).add(a).add(b).build();
-        assert_eq!(union.display(&db).to_string(), "A | B");
-        let reversed_union = UnionBuilder::new(&db).add(b).add(a).build();
-        assert_eq!(reversed_union.display(&db).to_string(), "B | A");
-        let intersection = IntersectionBuilder::new(&db)
-            .add_positive(union)
-            .add_positive(reversed_union)
-            .build();
-        assert_eq!(intersection.display(&db).to_string(), "B | A");
-    }
-
-    #[test]
-    fn build_union_of_two_intersections_simplify() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/module.py",
-            "
-            class A: ...
-            class B: ...
-            a = A()
-            b = B()
-        ",
-        )
-        .unwrap();
-
-        let file = system_path_to_file(&db, "src/module.py").expect("file to exist");
-
-        let a = global_symbol(&db, file, "a").expect_type();
-        let b = global_symbol(&db, file, "b").expect_type();
-        let intersection = IntersectionBuilder::new(&db)
-            .add_positive(a)
-            .add_positive(b)
-            .build();
-        let reversed_intersection = IntersectionBuilder::new(&db)
-            .add_positive(b)
-            .add_positive(a)
-            .build();
-        let union = UnionBuilder::new(&db)
-            .add(intersection)
-            .add(reversed_intersection)
-            .build();
-        assert_eq!(union.display(&db).to_string(), "A & B");
-    }
 }

crates/red_knot_python_semantic/src/types/diagnostic.rs

@@ -1,15 +1,14 @@
-use crate::types::{ClassLiteralType, Type};
-use crate::Db;
-use ruff_db::diagnostic::{Diagnostic, Severity};
 use ruff_db::files::File;
 use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_text_size::{Ranged, TextRange};
-use std::borrow::Cow;
 use std::fmt::Formatter;
 use std::ops::Deref;
 use std::sync::Arc;
 
-#[derive(Debug, Eq, PartialEq, Clone)]
+use crate::types::Type;
+use crate::Db;
+
+#[derive(Debug, Eq, PartialEq)]
 pub struct TypeCheckDiagnostic {
     // TODO: Don't use string keys for rules
     pub(super) rule: String,
@@ -32,28 +31,6 @@ impl TypeCheckDiagnostic {
     }
 }
 
-impl Diagnostic for TypeCheckDiagnostic {
-    fn rule(&self) -> &str {
-        TypeCheckDiagnostic::rule(self)
-    }
-
-    fn message(&self) -> Cow<str> {
-        TypeCheckDiagnostic::message(self).into()
-    }
-
-    fn file(&self) -> File {
-        TypeCheckDiagnostic::file(self)
-    }
-
-    fn range(&self) -> Option<TextRange> {
-        Some(Ranged::range(self))
-    }
-
-    fn severity(&self) -> Severity {
-        Severity::Error
-    }
-}
-
 impl Ranged for TypeCheckDiagnostic {
     fn range(&self) -> TextRange {
         self.range
@@ -73,6 +50,10 @@ pub struct TypeCheckDiagnostics {
 }
 
 impl TypeCheckDiagnostics {
+    pub fn new() -> Self {
+        Self { inner: Vec::new() }
+    }
+
     pub(super) fn push(&mut self, diagnostic: TypeCheckDiagnostic) {
         self.inner.push(Arc::new(diagnostic));
     }
@@ -144,7 +125,7 @@ impl<'db> TypeCheckDiagnosticsBuilder<'db> {
         Self {
             db,
             file,
-            diagnostics: TypeCheckDiagnostics::default(),
+            diagnostics: TypeCheckDiagnostics::new(),
         }
     }
 
@@ -160,23 +141,6 @@ impl<'db> TypeCheckDiagnosticsBuilder<'db> {
         );
     }
 
-    /// Emit a diagnostic declaring that the object represented by `node` is not iterable
-    /// because its `__iter__` method is possibly unbound.
-    pub(super) fn add_not_iterable_possibly_unbound(
-        &mut self,
-        node: AnyNodeRef,
-        element_ty: Type<'db>,
-    ) {
-        self.add(
-            node,
-            "not-iterable",
-            format_args!(
-                "Object of type `{}` is not iterable because its `__iter__` method is possibly unbound",
-                element_ty.display(self.db)
-            ),
-        );
-    }
-
     /// Emit a diagnostic declaring that an index is out of bounds for a tuple.
     pub(super) fn add_index_out_of_bounds(
         &mut self,
@@ -245,7 +209,7 @@ impl<'db> TypeCheckDiagnosticsBuilder<'db> {
         assigned_ty: Type<'db>,
     ) {
         match declared_ty {
-            Type::ClassLiteral(ClassLiteralType { class }) => {
+            Type::ClassLiteral(class) => {
                 self.add(node, "invalid-assignment", format_args!(
                         "Implicit shadowing of class `{}`; annotate to make it explicit if this is intentional",
                         class.name(self.db)));

crates/red_knot_python_semantic/src/types/display.rs

@@ -1,15 +1,12 @@
 //! Display implementations for types.
 
-use std::fmt::{self, Display, Formatter, Write};
+use std::fmt::{self, Display, Formatter};
 
 use ruff_db::display::FormatterJoinExtension;
 use ruff_python_ast::str::Quote;
 use ruff_python_literal::escape::AsciiEscape;
 
-use crate::types::{
-    ClassLiteralType, InstanceType, IntersectionType, KnownClass, StringLiteralType,
-    SubclassOfType, Type, UnionType,
-};
+use crate::types::{IntersectionType, Type, UnionType};
 use crate::Db;
 use rustc_hash::FxHashMap;
 
@@ -67,14 +64,7 @@ impl Display for DisplayRepresentation<'_> {
             Type::Any => f.write_str("Any"),
             Type::Never => f.write_str("Never"),
             Type::Unknown => f.write_str("Unknown"),
-            Type::Instance(InstanceType { class }) => {
-                let representation = match class.known(self.db) {
-                    Some(KnownClass::NoneType) => "None",
-                    Some(KnownClass::NoDefaultType) => "NoDefault",
-                    _ => class.name(self.db),
-                };
-                f.write_str(representation)
-            }
+            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"),
@@ -82,17 +72,16 @@ impl Display for DisplayRepresentation<'_> {
                 write!(f, "<module '{:?}'>", file.path(self.db))
             }
             // TODO functions and classes should display using a fully qualified name
-            Type::ClassLiteral(ClassLiteralType { class }) => f.write_str(class.name(self.db)),
-            Type::SubclassOf(SubclassOfType { class }) => {
-                write!(f, "type[{}]", class.name(self.db))
-            }
-            Type::KnownInstance(known_instance) => f.write_str(known_instance.repr(self.db)),
+            Type::ClassLiteral(class) => f.write_str(class.name(self.db)),
+            Type::Instance(class) => f.write_str(class.name(self.db)),
             Type::FunctionLiteral(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::StringLiteral(string) => string.display(self.db).fmt(f),
+            Type::StringLiteral(string) => {
+                write!(f, r#""{}""#, string.value(self.db).replace('"', r#"\""#))
+            }
             Type::LiteralString => f.write_str("LiteralString"),
             Type::BytesLiteral(bytes) => {
                 let escape =
@@ -327,40 +316,15 @@ impl<'db> Display for DisplayTypeArray<'_, 'db> {
     }
 }
 
-impl<'db> StringLiteralType<'db> {
-    fn display(&'db self, db: &'db dyn Db) -> DisplayStringLiteralType<'db> {
-        DisplayStringLiteralType { db, ty: self }
-    }
-}
-
-struct DisplayStringLiteralType<'db> {
-    ty: &'db StringLiteralType<'db>,
-    db: &'db dyn Db,
-}
-
-impl Display for DisplayStringLiteralType<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        let value = self.ty.value(self.db);
-        f.write_char('"')?;
-        for ch in value.chars() {
-            match ch {
-                // `escape_debug` will escape even single quotes, which is not necessary for our
-                // use case as we are already using double quotes to wrap the string.
-                '\'' => f.write_char('\'')?,
-                _ => write!(f, "{}", ch.escape_debug())?,
-            }
-        }
-        f.write_char('"')
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use ruff_db::files::system_path_to_file;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
 
     use crate::db::tests::TestDb;
-    use crate::types::{global_symbol, SliceLiteralType, StringLiteralType, Type, UnionType};
+    use crate::types::{
+        global_symbol, BytesLiteralType, SliceLiteralType, StringLiteralType, Type, UnionType,
+    };
     use crate::{Program, ProgramSettings, PythonVersion, SearchPathSettings};
 
     fn setup_db() -> TestDb {
@@ -406,17 +370,17 @@ mod tests {
             Type::Unknown,
             Type::IntLiteral(-1),
             global_symbol(&db, mod_file, "A").expect_type(),
-            Type::string_literal(&db, "A"),
-            Type::bytes_literal(&db, &[0u8]),
-            Type::bytes_literal(&db, &[7u8]),
+            Type::StringLiteral(StringLiteralType::new(&db, "A")),
+            Type::BytesLiteral(BytesLiteralType::new(&db, [0u8].as_slice())),
+            Type::BytesLiteral(BytesLiteralType::new(&db, [7u8].as_slice())),
             Type::IntLiteral(0),
             Type::IntLiteral(1),
-            Type::string_literal(&db, "B"),
+            Type::StringLiteral(StringLiteralType::new(&db, "B")),
             global_symbol(&db, mod_file, "foo").expect_type(),
             global_symbol(&db, mod_file, "bar").expect_type(),
             global_symbol(&db, mod_file, "B").expect_type(),
             Type::BooleanLiteral(true),
-            Type::none(&db),
+            Type::None,
         ];
         let union = UnionType::from_elements(&db, union_elements).expect_union();
         let display = format!("{}", union.display(&db));
@@ -477,28 +441,4 @@ mod tests {
             "slice[None, None, Literal[2]]"
         );
     }
-
-    #[test]
-    fn string_literal_display() {
-        let db = setup_db();
-
-        assert_eq!(
-            Type::StringLiteral(StringLiteralType::new(&db, r"\n"))
-                .display(&db)
-                .to_string(),
-            r#"Literal["\\n"]"#
-        );
-        assert_eq!(
-            Type::StringLiteral(StringLiteralType::new(&db, "'"))
-                .display(&db)
-                .to_string(),
-            r#"Literal["'"]"#
-        );
-        assert_eq!(
-            Type::StringLiteral(StringLiteralType::new(&db, r#"""#))
-                .display(&db)
-                .to_string(),
-            r#"Literal["\""]"#
-        );
-    }
 }

crates/red_knot_python_semantic/src/types/mro.rs

@@ -1,455 +0,0 @@
-use std::collections::VecDeque;
-use std::ops::Deref;
-
-use itertools::Either;
-use rustc_hash::FxHashSet;
-
-use super::{Class, ClassLiteralType, KnownClass, KnownInstanceType, Type};
-use crate::Db;
-
-/// The inferred method resolution order of a given class.
-///
-/// See [`Class::iter_mro`] for more details.
-#[derive(PartialEq, Eq, Clone, Debug)]
-pub(super) struct Mro<'db>(Box<[ClassBase<'db>]>);
-
-impl<'db> Mro<'db> {
-    /// Attempt to resolve the MRO of a given class
-    ///
-    /// In the event that a possible list of bases would (or could) lead to a
-    /// `TypeError` being raised at runtime due to an unresolvable MRO, we infer
-    /// the MRO of the class as being `[<the class in question>, Unknown, object]`.
-    /// This seems most likely to reduce the possibility of cascading errors
-    /// elsewhere.
-    ///
-    /// (We emit a diagnostic warning about the runtime `TypeError` in
-    /// [`super::infer::TypeInferenceBuilder::infer_region_scope`].)
-    pub(super) fn of_class(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroError<'db>> {
-        Self::of_class_impl(db, class).map_err(|error_kind| MroError {
-            kind: error_kind,
-            fallback_mro: Self::from_error(db, class),
-        })
-    }
-
-    pub(super) fn from_error(db: &'db dyn Db, class: Class<'db>) -> Self {
-        Self::from([
-            ClassBase::Class(class),
-            ClassBase::Unknown,
-            ClassBase::object(db),
-        ])
-    }
-
-    fn of_class_impl(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroErrorKind<'db>> {
-        let class_bases = class.explicit_bases(db);
-
-        if !class_bases.is_empty() && class.is_cyclically_defined(db) {
-            // We emit errors for cyclically defined classes elsewhere.
-            // It's important that we don't even try to infer the MRO for a cyclically defined class,
-            // or we'll end up in an infinite loop.
-            return Ok(Mro::from_error(db, class));
-        }
-
-        match class_bases {
-            // `builtins.object` is the special case:
-            // the only class in Python that has an MRO with length <2
-            [] if class.is_known(db, KnownClass::Object) => {
-                Ok(Self::from([ClassBase::Class(class)]))
-            }
-
-            // All other classes in Python have an MRO with length >=2.
-            // Even if a class has no explicit base classes,
-            // it will implicitly inherit from `object` at runtime;
-            // `object` will appear in the class's `__bases__` list and `__mro__`:
-            //
-            // ```pycon
-            // >>> class Foo: ...
-            // ...
-            // >>> Foo.__bases__
-            // (<class 'object'>,)
-            // >>> Foo.__mro__
-            // (<class '__main__.Foo'>, <class 'object'>)
-            // ```
-            [] => Ok(Self::from([ClassBase::Class(class), ClassBase::object(db)])),
-
-            // Fast path for a class that has only a single explicit base.
-            //
-            // This *could* theoretically be handled by the final branch below,
-            // but it's a common case (i.e., worth optimizing for),
-            // and the `c3_merge` function requires lots of allocations.
-            [single_base] => {
-                let single_base = ClassBase::try_from_ty(*single_base).ok_or(*single_base);
-                single_base.map_or_else(
-                    |invalid_base_ty| {
-                        let bases_info = Box::from([(0, invalid_base_ty)]);
-                        Err(MroErrorKind::InvalidBases(bases_info))
-                    },
-                    |single_base| {
-                        let mro = std::iter::once(ClassBase::Class(class))
-                            .chain(single_base.mro(db))
-                            .collect();
-                        Ok(mro)
-                    },
-                )
-            }
-
-            // The class has multiple explicit bases.
-            //
-            // We'll fallback to a full implementation of the C3-merge algorithm to determine
-            // what MRO Python will give this class at runtime
-            // (if an MRO is indeed resolvable at all!)
-            multiple_bases => {
-                let mut valid_bases = vec![];
-                let mut invalid_bases = vec![];
-
-                for (i, base) in multiple_bases.iter().enumerate() {
-                    match ClassBase::try_from_ty(*base).ok_or(*base) {
-                        Ok(valid_base) => valid_bases.push(valid_base),
-                        Err(invalid_base) => invalid_bases.push((i, invalid_base)),
-                    }
-                }
-
-                if !invalid_bases.is_empty() {
-                    return Err(MroErrorKind::InvalidBases(invalid_bases.into_boxed_slice()));
-                }
-
-                let mut seqs = vec![VecDeque::from([ClassBase::Class(class)])];
-                for base in &valid_bases {
-                    seqs.push(base.mro(db).collect());
-                }
-                seqs.push(valid_bases.iter().copied().collect());
-
-                c3_merge(seqs).ok_or_else(|| {
-                    let mut seen_bases = FxHashSet::default();
-                    let mut duplicate_bases = vec![];
-                    for (index, base) in valid_bases
-                        .iter()
-                        .enumerate()
-                        .filter_map(|(index, base)| Some((index, base.into_class_literal_type()?)))
-                    {
-                        if !seen_bases.insert(base) {
-                            duplicate_bases.push((index, base));
-                        }
-                    }
-
-                    if duplicate_bases.is_empty() {
-                        MroErrorKind::UnresolvableMro {
-                            bases_list: valid_bases.into_boxed_slice(),
-                        }
-                    } else {
-                        MroErrorKind::DuplicateBases(duplicate_bases.into_boxed_slice())
-                    }
-                })
-            }
-        }
-    }
-}
-
-impl<'db, const N: usize> From<[ClassBase<'db>; N]> for Mro<'db> {
-    fn from(value: [ClassBase<'db>; N]) -> Self {
-        Self(Box::from(value))
-    }
-}
-
-impl<'db> From<Vec<ClassBase<'db>>> for Mro<'db> {
-    fn from(value: Vec<ClassBase<'db>>) -> Self {
-        Self(value.into_boxed_slice())
-    }
-}
-
-impl<'db> Deref for Mro<'db> {
-    type Target = [ClassBase<'db>];
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl<'db> FromIterator<ClassBase<'db>> for Mro<'db> {
-    fn from_iter<T: IntoIterator<Item = ClassBase<'db>>>(iter: T) -> Self {
-        Self(iter.into_iter().collect())
-    }
-}
-
-/// Iterator that yields elements of a class's MRO.
-///
-/// We avoid materialising the *full* MRO unless it is actually necessary:
-/// - Materialising the full MRO is expensive
-/// - We need to do it for every class in the code that we're checking, as we need to make sure
-///   that there are no class definitions in the code we're checking that would cause an
-///   exception to be raised at runtime. But the same does *not* necessarily apply for every class
-///   in third-party and stdlib dependencies: we never emit diagnostics about non-first-party code.
-/// - However, we *do* need to resolve attribute accesses on classes/instances from
-///   third-party and stdlib dependencies. That requires iterating over the MRO of third-party/stdlib
-///   classes, but not necessarily the *whole* MRO: often just the first element is enough.
-///   Luckily we know that for any class `X`, the first element of `X`'s MRO will always be `X` itself.
-///   We can therefore avoid resolving the full MRO for many third-party/stdlib classes while still
-///   being faithful to the runtime semantics.
-///
-/// Even for first-party code, where we will have to resolve the MRO for every class we encounter,
-/// loading the cached MRO comes with a certain amount of overhead, so it's best to avoid calling the
-/// Salsa-tracked [`Class::try_mro`] method unless it's absolutely necessary.
-pub(super) struct MroIterator<'db> {
-    db: &'db dyn Db,
-
-    /// The class whose MRO we're iterating over
-    class: Class<'db>,
-
-    /// Whether or not we've already yielded the first element of the MRO
-    first_element_yielded: bool,
-
-    /// Iterator over all elements of the MRO except the first.
-    ///
-    /// The full MRO is expensive to materialize, so this field is `None`
-    /// unless we actually *need* to iterate past the first element of the MRO,
-    /// at which point it is lazily materialized.
-    subsequent_elements: Option<std::slice::Iter<'db, ClassBase<'db>>>,
-}
-
-impl<'db> MroIterator<'db> {
-    pub(super) fn new(db: &'db dyn Db, class: Class<'db>) -> Self {
-        Self {
-            db,
-            class,
-            first_element_yielded: false,
-            subsequent_elements: None,
-        }
-    }
-
-    /// Materialize the full MRO of the class.
-    /// Return an iterator over that MRO which skips the first element of the MRO.
-    fn full_mro_except_first_element(&mut self) -> impl Iterator<Item = ClassBase<'db>> + '_ {
-        self.subsequent_elements
-            .get_or_insert_with(|| {
-                let mut full_mro_iter = match self.class.try_mro(self.db) {
-                    Ok(mro) => mro.iter(),
-                    Err(error) => error.fallback_mro().iter(),
-                };
-                full_mro_iter.next();
-                full_mro_iter
-            })
-            .copied()
-    }
-}
-
-impl<'db> Iterator for MroIterator<'db> {
-    type Item = ClassBase<'db>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if !self.first_element_yielded {
-            self.first_element_yielded = true;
-            return Some(ClassBase::Class(self.class));
-        }
-        self.full_mro_except_first_element().next()
-    }
-}
-
-impl std::iter::FusedIterator for MroIterator<'_> {}
-
-#[derive(Debug, PartialEq, Eq)]
-pub(super) struct MroError<'db> {
-    kind: MroErrorKind<'db>,
-    fallback_mro: Mro<'db>,
-}
-
-impl<'db> MroError<'db> {
-    /// Return an [`MroErrorKind`] variant describing why we could not resolve the MRO for this class.
-    pub(super) fn reason(&self) -> &MroErrorKind<'db> {
-        &self.kind
-    }
-
-    /// Return the fallback MRO we should infer for this class during type inference
-    /// (since accurate resolution of its "true" MRO was impossible)
-    pub(super) fn fallback_mro(&self) -> &Mro<'db> {
-        &self.fallback_mro
-    }
-}
-
-/// Possible ways in which attempting to resolve the MRO of a class might fail.
-#[derive(Debug, PartialEq, Eq)]
-pub(super) enum MroErrorKind<'db> {
-    /// The class inherits from one or more invalid bases.
-    ///
-    /// To avoid excessive complexity in our implementation,
-    /// we only permit classes to inherit from class-literal types,
-    /// `Todo`, `Unknown` or `Any`. Anything else results in us
-    /// emitting a diagnostic.
-    ///
-    /// This variant records the indices and types of class bases
-    /// that we deem to be invalid. The indices are the indices of nodes
-    /// in the bases list of the class's [`StmtClassDef`](ruff_python_ast::StmtClassDef) node.
-    /// Each index is the index of a node representing an invalid base.
-    InvalidBases(Box<[(usize, Type<'db>)]>),
-
-    /// The class has one or more duplicate bases.
-    ///
-    /// This variant records the indices and [`Class`]es
-    /// of the duplicate bases. The indices are the indices of nodes
-    /// in the bases list of the class's [`StmtClassDef`](ruff_python_ast::StmtClassDef) node.
-    /// Each index is the index of a node representing a duplicate base.
-    DuplicateBases(Box<[(usize, Class<'db>)]>),
-
-    /// The MRO is otherwise unresolvable through the C3-merge algorithm.
-    ///
-    /// See [`c3_merge`] for more details.
-    UnresolvableMro { bases_list: Box<[ClassBase<'db>]> },
-}
-
-/// Enumeration of the possible kinds of types we allow in class bases.
-///
-/// This is much more limited than the [`Type`] enum:
-/// all types that would be invalid to have as a class base are
-/// transformed into [`ClassBase::Unknown`]
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub(super) enum ClassBase<'db> {
-    Any,
-    Unknown,
-    Todo,
-    Class(Class<'db>),
-}
-
-impl<'db> ClassBase<'db> {
-    pub(super) fn display(self, db: &'db dyn Db) -> impl std::fmt::Display + 'db {
-        struct Display<'db> {
-            base: ClassBase<'db>,
-            db: &'db dyn Db,
-        }
-
-        impl std::fmt::Display for Display<'_> {
-            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                match self.base {
-                    ClassBase::Any => f.write_str("Any"),
-                    ClassBase::Todo => f.write_str("Todo"),
-                    ClassBase::Unknown => f.write_str("Unknown"),
-                    ClassBase::Class(class) => write!(f, "<class '{}'>", class.name(self.db)),
-                }
-            }
-        }
-
-        Display { base: self, db }
-    }
-
-    #[cfg(test)]
-    #[track_caller]
-    pub(super) fn expect_class_base(self) -> Class<'db> {
-        match self {
-            ClassBase::Class(class) => class,
-            _ => panic!("Expected a `ClassBase::Class()` variant"),
-        }
-    }
-
-    /// Return a `ClassBase` representing the class `builtins.object`
-    fn object(db: &'db dyn Db) -> Self {
-        KnownClass::Object
-            .to_class_literal(db)
-            .into_class_literal()
-            .map_or(Self::Unknown, |ClassLiteralType { class }| {
-                Self::Class(class)
-            })
-    }
-
-    /// Attempt to resolve `ty` into a `ClassBase`.
-    ///
-    /// Return `None` if `ty` is not an acceptable type for a class base.
-    fn try_from_ty(ty: Type<'db>) -> Option<Self> {
-        match ty {
-            Type::Any => Some(Self::Any),
-            Type::Unknown => Some(Self::Unknown),
-            Type::Todo => Some(Self::Todo),
-            Type::ClassLiteral(ClassLiteralType { class }) => Some(Self::Class(class)),
-            Type::Union(_) => None, // TODO -- forces consideration of multiple possible MROs?
-            Type::Intersection(_) => None, // TODO -- probably incorrect?
-            Type::Instance(_) => None, // TODO -- handle `__mro_entries__`?
-            Type::Never
-            | Type::BooleanLiteral(_)
-            | Type::FunctionLiteral(_)
-            | Type::BytesLiteral(_)
-            | Type::IntLiteral(_)
-            | Type::StringLiteral(_)
-            | Type::LiteralString
-            | Type::Tuple(_)
-            | Type::SliceLiteral(_)
-            | Type::ModuleLiteral(_)
-            | Type::SubclassOf(_) => None,
-            Type::KnownInstance(known_instance) => match known_instance {
-                KnownInstanceType::TypeVar(_)
-                | KnownInstanceType::Literal
-                | KnownInstanceType::Optional => None,
-            },
-        }
-    }
-
-    fn into_class_literal_type(self) -> Option<Class<'db>> {
-        match self {
-            Self::Class(class) => Some(class),
-            _ => None,
-        }
-    }
-
-    /// Iterate over the MRO of this base
-    fn mro(
-        self,
-        db: &'db dyn Db,
-    ) -> Either<impl Iterator<Item = ClassBase<'db>>, impl Iterator<Item = ClassBase<'db>>> {
-        match self {
-            ClassBase::Any => Either::Left([ClassBase::Any, ClassBase::object(db)].into_iter()),
-            ClassBase::Unknown => {
-                Either::Left([ClassBase::Unknown, ClassBase::object(db)].into_iter())
-            }
-            ClassBase::Todo => Either::Left([ClassBase::Todo, ClassBase::object(db)].into_iter()),
-            ClassBase::Class(class) => Either::Right(class.iter_mro(db)),
-        }
-    }
-}
-
-impl<'db> From<ClassBase<'db>> for Type<'db> {
-    fn from(value: ClassBase<'db>) -> Self {
-        match value {
-            ClassBase::Any => Type::Any,
-            ClassBase::Todo => Type::Todo,
-            ClassBase::Unknown => Type::Unknown,
-            ClassBase::Class(class) => Type::class_literal(class),
-        }
-    }
-}
-
-/// Implementation of the [C3-merge algorithm] for calculating a Python class's
-/// [method resolution order].
-///
-/// [C3-merge algorithm]: https://docs.python.org/3/howto/mro.html#python-2-3-mro
-/// [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
-fn c3_merge(mut sequences: Vec<VecDeque<ClassBase>>) -> Option<Mro> {
-    // Most MROs aren't that long...
-    let mut mro = Vec::with_capacity(8);
-
-    loop {
-        sequences.retain(|sequence| !sequence.is_empty());
-
-        if sequences.is_empty() {
-            return Some(Mro::from(mro));
-        }
-
-        // If the candidate exists "deeper down" in the inheritance hierarchy,
-        // we should refrain from adding it to the MRO for now. Add the first candidate
-        // for which this does not hold true. If this holds true for all candidates,
-        // return `None`; it will be impossible to find a consistent MRO for the class
-        // with the given bases.
-        let mro_entry = sequences.iter().find_map(|outer_sequence| {
-            let candidate = outer_sequence[0];
-
-            let not_head = sequences
-                .iter()
-                .all(|sequence| sequence.iter().skip(1).all(|base| base != &candidate));
-
-            not_head.then_some(candidate)
-        })?;
-
-        mro.push(mro_entry);
-
-        // Make sure we don't try to add the candidate to the MRO twice:
-        for sequence in &mut sequences {
-            if sequence[0] == mro_entry {
-                sequence.pop_front();
-            }
-        }
-    }
-}

crates/red_knot_python_semantic/src/types/narrow.rs

@@ -1,19 +1,16 @@
-use crate::semantic_index::ast_ids::HasScopedExpressionId;
+use crate::semantic_index::ast_ids::HasScopedAstId;
 use crate::semantic_index::constraint::{Constraint, ConstraintNode, 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, ClassLiteralType, IntersectionBuilder, KnownClass,
-    KnownConstraintFunction, KnownFunction, Truthiness, Type, UnionBuilder,
+    infer_expression_types, IntersectionBuilder, KnownFunction, Type, UnionBuilder,
 };
 use crate::Db;
 use itertools::Itertools;
 use ruff_python_ast as ast;
-use ruff_python_ast::{BoolOp, ExprBoolOp};
 use rustc_hash::FxHashMap;
-use std::collections::hash_map::Entry;
 use std::sync::Arc;
 
 /// Return the type constraint that `test` (if true) would place on `definition`, if any.
@@ -37,20 +34,21 @@ pub(crate) fn narrowing_constraint<'db>(
     constraint: Constraint<'db>,
     definition: Definition<'db>,
 ) -> Option<Type<'db>> {
-    let constraints = match constraint.node {
+    match constraint.node {
         ConstraintNode::Expression(expression) => {
             if constraint.is_positive {
                 all_narrowing_constraints_for_expression(db, expression)
+                    .get(&definition.symbol(db))
+                    .copied()
             } else {
                 all_negative_narrowing_constraints_for_expression(db, expression)
+                    .get(&definition.symbol(db))
+                    .copied()
             }
         }
-        ConstraintNode::Pattern(pattern) => all_narrowing_constraints_for_pattern(db, pattern),
-    };
-    if let Some(constraints) = constraints {
-        constraints.get(&definition.symbol(db)).copied()
-    } else {
-        None
+        ConstraintNode::Pattern(pattern) => all_narrowing_constraints_for_pattern(db, pattern)
+            .get(&definition.symbol(db))
+            .copied(),
     }
 }
 
@@ -58,7 +56,7 @@ pub(crate) fn narrowing_constraint<'db>(
 fn all_narrowing_constraints_for_pattern<'db>(
     db: &'db dyn Db,
     pattern: PatternConstraint<'db>,
-) -> Option<NarrowingConstraints<'db>> {
+) -> NarrowingConstraints<'db> {
     NarrowingConstraintsBuilder::new(db, ConstraintNode::Pattern(pattern), true).finish()
 }
 
@@ -66,7 +64,7 @@ fn all_narrowing_constraints_for_pattern<'db>(
 fn all_narrowing_constraints_for_expression<'db>(
     db: &'db dyn Db,
     expression: Expression<'db>,
-) -> Option<NarrowingConstraints<'db>> {
+) -> NarrowingConstraints<'db> {
     NarrowingConstraintsBuilder::new(db, ConstraintNode::Expression(expression), true).finish()
 }
 
@@ -74,83 +72,39 @@ fn all_narrowing_constraints_for_expression<'db>(
 fn all_negative_narrowing_constraints_for_expression<'db>(
     db: &'db dyn Db,
     expression: Expression<'db>,
-) -> Option<NarrowingConstraints<'db>> {
+) -> NarrowingConstraints<'db> {
     NarrowingConstraintsBuilder::new(db, ConstraintNode::Expression(expression), false).finish()
 }
 
-/// Generate a constraint from the type of a `classinfo` argument to `isinstance` or `issubclass`.
+/// Generate a constraint from the *type* of the second argument of an `isinstance` call.
 ///
-/// The `classinfo` argument can be a class literal, a tuple of (tuples of) class literals. PEP 604
-/// union types are not yet supported. Returns `None` if the `classinfo` argument has a wrong type.
-fn generate_classinfo_constraint<'db, F>(
+/// Example: for `isinstance(…, str)`, we would infer `Type::ClassLiteral(str)` from the
+/// second argument, but we need to generate a `Type::Instance(str)` constraint that can
+/// be used to narrow down the type of the first argument.
+fn generate_isinstance_constraint<'db>(
     db: &'db dyn Db,
     classinfo: &Type<'db>,
-    to_constraint: F,
-) -> Option<Type<'db>>
-where
-    F: Fn(ClassLiteralType<'db>) -> Type<'db> + Copy,
-{
+) -> Option<Type<'db>> {
     match classinfo {
+        Type::ClassLiteral(class) => Some(Type::Instance(*class)),
         Type::Tuple(tuple) => {
             let mut builder = UnionBuilder::new(db);
             for element in tuple.elements(db) {
-                builder = builder.add(generate_classinfo_constraint(db, element, to_constraint)?);
+                builder = builder.add(generate_isinstance_constraint(db, element)?);
             }
             Some(builder.build())
         }
-        Type::ClassLiteral(class_literal_type) => Some(to_constraint(*class_literal_type)),
         _ => None,
     }
 }
 
 type NarrowingConstraints<'db> = FxHashMap<ScopedSymbolId, Type<'db>>;
 
-fn merge_constraints_and<'db>(
-    into: &mut NarrowingConstraints<'db>,
-    from: NarrowingConstraints<'db>,
-    db: &'db dyn Db,
-) {
-    for (key, value) in from {
-        match into.entry(key) {
-            Entry::Occupied(mut entry) => {
-                *entry.get_mut() = IntersectionBuilder::new(db)
-                    .add_positive(*entry.get())
-                    .add_positive(value)
-                    .build();
-            }
-            Entry::Vacant(entry) => {
-                entry.insert(value);
-            }
-        }
-    }
-}
-
-fn merge_constraints_or<'db>(
-    into: &mut NarrowingConstraints<'db>,
-    from: &NarrowingConstraints<'db>,
-    db: &'db dyn Db,
-) {
-    for (key, value) in from {
-        match into.entry(*key) {
-            Entry::Occupied(mut entry) => {
-                *entry.get_mut() = UnionBuilder::new(db).add(*entry.get()).add(*value).build();
-            }
-            Entry::Vacant(entry) => {
-                entry.insert(KnownClass::Object.to_instance(db));
-            }
-        }
-    }
-    for (key, value) in into.iter_mut() {
-        if !from.contains_key(key) {
-            *value = KnownClass::Object.to_instance(db);
-        }
-    }
-}
-
 struct NarrowingConstraintsBuilder<'db> {
     db: &'db dyn Db,
     constraint: ConstraintNode<'db>,
     is_positive: bool,
+    constraints: NarrowingConstraints<'db>,
 }
 
 impl<'db> NarrowingConstraintsBuilder<'db> {
@@ -159,31 +113,24 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
             db,
             constraint,
             is_positive,
+            constraints: NarrowingConstraints::default(),
         }
     }
 
-    fn finish(mut self) -> Option<NarrowingConstraints<'db>> {
-        let constraints: Option<NarrowingConstraints<'db>> = match self.constraint {
+    fn finish(mut self) -> NarrowingConstraints<'db> {
+        match self.constraint {
             ConstraintNode::Expression(expression) => {
-                self.evaluate_expression_constraint(expression, self.is_positive)
+                self.evaluate_expression_constraint(expression, self.is_positive);
             }
             ConstraintNode::Pattern(pattern) => self.evaluate_pattern_constraint(pattern),
-        };
-        if let Some(mut constraints) = constraints {
-            constraints.shrink_to_fit();
-            Some(constraints)
-        } else {
-            None
         }
+        self.constraints.shrink_to_fit();
+        self.constraints
     }
 
-    fn evaluate_expression_constraint(
-        &mut self,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
+    fn evaluate_expression_constraint(&mut self, expression: Expression<'db>, is_positive: bool) {
         let expression_node = expression.node_ref(self.db).node();
-        self.evaluate_expression_node_constraint(expression_node, expression, is_positive)
+        self.evaluate_expression_node_constraint(expression_node, expression, is_positive);
     }
 
     fn evaluate_expression_node_constraint(
@@ -191,51 +138,52 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         expression_node: &ruff_python_ast::Expr,
         expression: Expression<'db>,
         is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
+    ) {
         match expression_node {
             ast::Expr::Compare(expr_compare) => {
-                self.evaluate_expr_compare(expr_compare, expression, is_positive)
+                self.add_expr_compare(expr_compare, expression, is_positive);
             }
             ast::Expr::Call(expr_call) => {
-                self.evaluate_expr_call(expr_call, expression, is_positive)
+                self.add_expr_call(expr_call, expression, is_positive);
             }
-            ast::Expr::UnaryOp(unary_op) if unary_op.op == ast::UnaryOp::Not => self
-                .evaluate_expression_node_constraint(&unary_op.operand, expression, !is_positive),
-            ast::Expr::BoolOp(bool_op) => self.evaluate_bool_op(bool_op, expression, is_positive),
-            _ => None, // TODO other test expression kinds
+            ast::Expr::UnaryOp(unary_op) if unary_op.op == ast::UnaryOp::Not => {
+                self.evaluate_expression_node_constraint(
+                    &unary_op.operand,
+                    expression,
+                    !is_positive,
+                );
+            }
+            _ => {} // TODO other test expression kinds
         }
     }
 
-    fn evaluate_pattern_constraint(
-        &mut self,
-        pattern: PatternConstraint<'db>,
-    ) -> Option<NarrowingConstraints<'db>> {
+    fn evaluate_pattern_constraint(&mut self, pattern: PatternConstraint<'db>) {
         let subject = pattern.subject(self.db);
 
         match pattern.pattern(self.db).node() {
             ast::Pattern::MatchValue(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchSingleton(singleton_pattern) => {
-                self.evaluate_match_pattern_singleton(subject, singleton_pattern)
+                self.add_match_pattern_singleton(subject, singleton_pattern);
             }
             ast::Pattern::MatchSequence(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchMapping(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchClass(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchStar(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchAs(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchOr(_) => {
-                None // TODO
+                // TODO
             }
         }
     }
@@ -251,38 +199,29 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         }
     }
 
-    fn evaluate_expr_compare(
+    fn add_expr_compare(
         &mut self,
         expr_compare: &ast::ExprCompare,
         expression: Expression<'db>,
         is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
-        fn is_narrowing_target_candidate(expr: &ast::Expr) -> bool {
-            matches!(expr, ast::Expr::Name(_) | ast::Expr::Call(_))
-        }
-
+    ) {
         let ast::ExprCompare {
             range: _,
             left,
             ops,
             comparators,
         } = expr_compare;
-
-        // Performance optimization: early return if there are no potential narrowing targets.
-        if !is_narrowing_target_candidate(left)
-            && comparators
-                .iter()
-                .all(|c| !is_narrowing_target_candidate(c))
-        {
-            return None;
+        if !left.is_name_expr() && comparators.iter().all(|c| !c.is_name_expr()) {
+            // If none of the comparators are name expressions,
+            // we have no symbol to narrow down the type of.
+            return;
         }
-
         if !is_positive && comparators.len() > 1 {
             // We can't negate a constraint made by a multi-comparator expression, since we can't
             // know which comparison part is the one being negated.
             // For example, the negation of  `x is 1 is y is 2`, would be `(x is not 1) or (y is not 1) or (y is not 2)`
             // and that requires cross-symbol constraints, which we don't support yet.
-            return None;
+            return;
         }
         let scope = self.scope();
         let inference = infer_expression_types(self.db, expression);
@@ -290,218 +229,98 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         let comparator_tuples = std::iter::once(&**left)
             .chain(comparators)
             .tuple_windows::<(&ruff_python_ast::Expr, &ruff_python_ast::Expr)>();
-        let mut constraints = NarrowingConstraints::default();
         for (op, (left, right)) in std::iter::zip(&**ops, comparator_tuples) {
-            let rhs_ty = inference.expression_ty(right.scoped_expression_id(self.db, scope));
+            if let ast::Expr::Name(ast::ExprName {
+                range: _,
+                id,
+                ctx: _,
+            }) = left
+            {
+                // SAFETY: we should always have a symbol for every Name node.
+                let symbol = self.symbols().symbol_id_by_name(id).unwrap();
+                let rhs_ty = inference.expression_ty(right.scoped_ast_id(self.db, scope));
 
-            match left {
-                ast::Expr::Name(ast::ExprName {
-                    range: _,
-                    id,
-                    ctx: _,
-                }) => {
-                    let symbol = self
-                        .symbols()
-                        .symbol_id_by_name(id)
-                        .expect("Should always have a symbol for every Name node");
-
-                    match if is_positive { *op } else { op.negate() } {
-                        ast::CmpOp::IsNot => {
-                            if rhs_ty.is_singleton(self.db) {
-                                let ty = IntersectionBuilder::new(self.db)
-                                    .add_negative(rhs_ty)
-                                    .build();
-                                constraints.insert(symbol, ty);
-                            } else {
-                                // Non-singletons cannot be safely narrowed using `is not`
-                            }
+                match if is_positive { *op } else { op.negate() } {
+                    ast::CmpOp::IsNot => {
+                        if rhs_ty.is_singleton() {
+                            let ty = IntersectionBuilder::new(self.db)
+                                .add_negative(rhs_ty)
+                                .build();
+                            self.constraints.insert(symbol, ty);
+                        } else {
+                            // Non-singletons cannot be safely narrowed using `is not`
                         }
-                        ast::CmpOp::Is => {
-                            constraints.insert(symbol, rhs_ty);
-                        }
-                        ast::CmpOp::NotEq => {
-                            if rhs_ty.is_single_valued(self.db) {
-                                let ty = IntersectionBuilder::new(self.db)
-                                    .add_negative(rhs_ty)
-                                    .build();
-                                constraints.insert(symbol, ty);
-                            }
-                        }
-                        _ => {
-                            // TODO other comparison types
+                    }
+                    ast::CmpOp::Is => {
+                        self.constraints.insert(symbol, rhs_ty);
+                    }
+                    ast::CmpOp::NotEq => {
+                        if rhs_ty.is_single_valued(self.db) {
+                            let ty = IntersectionBuilder::new(self.db)
+                                .add_negative(rhs_ty)
+                                .build();
+                            self.constraints.insert(symbol, ty);
                         }
                     }
+                    _ => {
+                        // TODO other comparison types
+                    }
                 }
-                ast::Expr::Call(ast::ExprCall {
-                    range: _,
-                    func: callable,
-                    arguments:
-                        ast::Arguments {
-                            args,
-                            keywords,
-                            range: _,
-                        },
-                }) if rhs_ty.is_class_literal() && keywords.is_empty() => {
-                    let [ast::Expr::Name(ast::ExprName { id, .. })] = &**args else {
-                        continue;
-                    };
-
-                    let is_valid_constraint = if is_positive {
-                        op == &ast::CmpOp::Is
-                    } else {
-                        op == &ast::CmpOp::IsNot
-                    };
-
-                    if !is_valid_constraint {
-                        continue;
-                    }
-
-                    let callable_ty =
-                        inference.expression_ty(callable.scoped_expression_id(self.db, scope));
-
-                    if callable_ty
-                        .into_class_literal()
-                        .is_some_and(|c| c.class.is_known(self.db, KnownClass::Type))
-                    {
-                        let symbol = self
-                            .symbols()
-                            .symbol_id_by_name(id)
-                            .expect("Should always have a symbol for every Name node");
-                        constraints.insert(symbol, rhs_ty.to_instance(self.db));
-                    }
-                }
-                _ => {}
             }
         }
-        Some(constraints)
     }
 
-    fn evaluate_expr_call(
+    fn add_expr_call(
         &mut self,
         expr_call: &ast::ExprCall,
         expression: Expression<'db>,
         is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
+    ) {
         let scope = self.scope();
         let inference = infer_expression_types(self.db, expression);
 
-        // TODO: add support for PEP 604 union types on the right hand side of `isinstance`
-        // and `issubclass`, for example `isinstance(x, str | (int | float))`.
-        match inference
-            .expression_ty(expr_call.func.scoped_expression_id(self.db, scope))
-            .into_function_literal()
-            .and_then(|f| f.known(self.db))
-            .and_then(KnownFunction::constraint_function)
+        if let Some(func_type) = inference
+            .expression_ty(expr_call.func.scoped_ast_id(self.db, scope))
+            .into_function_literal_type()
         {
-            Some(function) if expr_call.arguments.keywords.is_empty() => {
-                if let [ast::Expr::Name(ast::ExprName { id, .. }), class_info] =
-                    &*expr_call.arguments.args
+            if func_type.is_known(self.db, KnownFunction::IsInstance)
+                && expr_call.arguments.keywords.is_empty()
+            {
+                if let [ast::Expr::Name(ast::ExprName { id, .. }), rhs] = &*expr_call.arguments.args
                 {
                     let symbol = self.symbols().symbol_id_by_name(id).unwrap();
 
-                    let class_info_ty =
-                        inference.expression_ty(class_info.scoped_expression_id(self.db, scope));
+                    let rhs_type = inference.expression_ty(rhs.scoped_ast_id(self.db, scope));
 
-                    let to_constraint = match function {
-                        KnownConstraintFunction::IsInstance => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::instance(class_literal.class)
-                            }
+                    // TODO: add support for PEP 604 union types on the right hand side:
+                    // isinstance(x, str | (int | float))
+                    if let Some(mut constraint) = generate_isinstance_constraint(self.db, &rhs_type)
+                    {
+                        if !is_positive {
+                            constraint = constraint.negate(self.db);
                         }
-                        KnownConstraintFunction::IsSubclass => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::subclass_of(class_literal.class)
-                            }
-                        }
-                    };
-
-                    generate_classinfo_constraint(self.db, &class_info_ty, to_constraint).map(
-                        |constraint| {
-                            let mut constraints = NarrowingConstraints::default();
-                            constraints.insert(symbol, constraint.negate_if(self.db, !is_positive));
-                            constraints
-                        },
-                    )
-                } else {
-                    None
+                        self.constraints.insert(symbol, constraint);
+                    }
                 }
             }
-            _ => None,
         }
     }
 
-    fn evaluate_match_pattern_singleton(
+    fn add_match_pattern_singleton(
         &mut self,
         subject: &ast::Expr,
         pattern: &ast::PatternMatchSingleton,
-    ) -> Option<NarrowingConstraints<'db>> {
+    ) {
         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(self.db),
+                ast::Singleton::None => Type::None,
                 ast::Singleton::True => Type::BooleanLiteral(true),
                 ast::Singleton::False => Type::BooleanLiteral(false),
             };
-            let mut constraints = NarrowingConstraints::default();
-            constraints.insert(symbol, ty);
-            Some(constraints)
-        } else {
-            None
-        }
-    }
-
-    fn evaluate_bool_op(
-        &mut self,
-        expr_bool_op: &ExprBoolOp,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
-        let inference = infer_expression_types(self.db, expression);
-        let scope = self.scope();
-        let mut sub_constraints = expr_bool_op
-            .values
-            .iter()
-            // filter our arms with statically known truthiness
-            .filter(|expr| {
-                inference
-                    .expression_ty(expr.scoped_expression_id(self.db, scope))
-                    .bool(self.db)
-                    != match expr_bool_op.op {
-                        BoolOp::And => Truthiness::AlwaysTrue,
-                        BoolOp::Or => Truthiness::AlwaysFalse,
-                    }
-            })
-            .map(|sub_expr| {
-                self.evaluate_expression_node_constraint(sub_expr, expression, is_positive)
-            })
-            .collect::<Vec<_>>();
-        match (expr_bool_op.op, is_positive) {
-            (BoolOp::And, true) | (BoolOp::Or, false) => {
-                let mut aggregation: Option<NarrowingConstraints> = None;
-                for sub_constraint in sub_constraints.into_iter().flatten() {
-                    if let Some(ref mut some_aggregation) = aggregation {
-                        merge_constraints_and(some_aggregation, sub_constraint, self.db);
-                    } else {
-                        aggregation = Some(sub_constraint);
-                    }
-                }
-                aggregation
-            }
-            (BoolOp::Or, true) | (BoolOp::And, false) => {
-                let (first, rest) = sub_constraints.split_first_mut()?;
-                if let Some(ref mut first) = first {
-                    for rest_constraint in rest {
-                        if let Some(rest_constraint) = rest_constraint {
-                            merge_constraints_or(first, rest_constraint, self.db);
-                        } else {
-                            return None;
-                        }
-                    }
-                }
-                first.clone()
-            }
+            self.constraints.insert(symbol, ty);
         }
     }
 }

crates/red_knot_python_semantic/src/types/signatures.rs

@@ -1,480 +0,0 @@
-#![allow(dead_code)]
-use super::{definition_expression_ty, Type};
-use crate::semantic_index::definition::Definition;
-use crate::Db;
-use ruff_python_ast::{self as ast, name::Name};
-
-/// A typed callable signature.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct Signature<'db> {
-    parameters: Parameters<'db>,
-
-    /// Annotated return type (Unknown if no annotation.)
-    pub(crate) return_ty: Type<'db>,
-}
-
-impl<'db> Signature<'db> {
-    /// Return a todo signature: (*args: Todo, **kwargs: Todo) -> Todo
-    pub(crate) fn todo() -> Self {
-        Self {
-            parameters: Parameters::todo(),
-            return_ty: Type::Todo,
-        }
-    }
-
-    /// Return a typed signature from a function definition.
-    pub(super) fn from_function(
-        db: &'db dyn Db,
-        definition: Definition<'db>,
-        function_node: &'db ast::StmtFunctionDef,
-    ) -> Self {
-        let return_ty = function_node
-            .returns
-            .as_ref()
-            .map(|returns| {
-                if function_node.is_async {
-                    // TODO: generic `types.CoroutineType`!
-                    Type::Todo
-                } else {
-                    definition_expression_ty(db, definition, returns.as_ref())
-                }
-            })
-            .unwrap_or(Type::Unknown);
-
-        Self {
-            parameters: Parameters::from_parameters(
-                db,
-                definition,
-                function_node.parameters.as_ref(),
-            ),
-            return_ty,
-        }
-    }
-}
-
-/// The parameters portion of a typed signature.
-///
-/// The ordering of parameters is always as given in this struct: first positional-only parameters,
-/// then positional-or-keyword, then optionally the variadic parameter, then keyword-only
-/// parameters, and last, optionally the variadic keywords parameter.
-#[derive(Clone, Debug, Default, PartialEq, Eq)]
-pub(super) struct Parameters<'db> {
-    /// Parameters which may only be filled by positional arguments.
-    positional_only: Box<[ParameterWithDefault<'db>]>,
-
-    /// Parameters which may be filled by positional or keyword arguments.
-    positional_or_keyword: Box<[ParameterWithDefault<'db>]>,
-
-    /// The `*args` variadic parameter, if any.
-    variadic: Option<Parameter<'db>>,
-
-    /// Parameters which may only be filled by keyword arguments.
-    keyword_only: Box<[ParameterWithDefault<'db>]>,
-
-    /// The `**kwargs` variadic keywords parameter, if any.
-    keywords: Option<Parameter<'db>>,
-}
-
-impl<'db> Parameters<'db> {
-    /// Return todo parameters: (*args: Todo, **kwargs: Todo)
-    fn todo() -> Self {
-        Self {
-            variadic: Some(Parameter {
-                name: Some(Name::new_static("args")),
-                annotated_ty: Type::Todo,
-            }),
-            keywords: Some(Parameter {
-                name: Some(Name::new_static("kwargs")),
-                annotated_ty: Type::Todo,
-            }),
-            ..Default::default()
-        }
-    }
-
-    fn from_parameters(
-        db: &'db dyn Db,
-        definition: Definition<'db>,
-        parameters: &'db ast::Parameters,
-    ) -> Self {
-        let ast::Parameters {
-            posonlyargs,
-            args,
-            vararg,
-            kwonlyargs,
-            kwarg,
-            range: _,
-        } = parameters;
-        let positional_only = posonlyargs
-            .iter()
-            .map(|arg| ParameterWithDefault::from_node(db, definition, arg))
-            .collect();
-        let positional_or_keyword = args
-            .iter()
-            .map(|arg| ParameterWithDefault::from_node(db, definition, arg))
-            .collect();
-        let variadic = vararg
-            .as_ref()
-            .map(|arg| Parameter::from_node(db, definition, arg));
-        let keyword_only = kwonlyargs
-            .iter()
-            .map(|arg| ParameterWithDefault::from_node(db, definition, arg))
-            .collect();
-        let keywords = kwarg
-            .as_ref()
-            .map(|arg| Parameter::from_node(db, definition, arg));
-        Self {
-            positional_only,
-            positional_or_keyword,
-            variadic,
-            keyword_only,
-            keywords,
-        }
-    }
-}
-
-/// A single parameter of a typed signature, with optional default value.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(super) struct ParameterWithDefault<'db> {
-    parameter: Parameter<'db>,
-
-    /// Type of the default value, if any.
-    default_ty: Option<Type<'db>>,
-}
-
-impl<'db> ParameterWithDefault<'db> {
-    fn from_node(
-        db: &'db dyn Db,
-        definition: Definition<'db>,
-        parameter_with_default: &'db ast::ParameterWithDefault,
-    ) -> Self {
-        Self {
-            default_ty: parameter_with_default
-                .default
-                .as_deref()
-                .map(|default| definition_expression_ty(db, definition, default)),
-            parameter: Parameter::from_node(db, definition, &parameter_with_default.parameter),
-        }
-    }
-}
-
-/// A single parameter of a typed signature.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(super) struct Parameter<'db> {
-    /// Parameter name.
-    ///
-    /// It is possible for signatures to be defined in ways that leave positional-only parameters
-    /// nameless (e.g. via `Callable` annotations).
-    name: Option<Name>,
-
-    /// Annotated type of the parameter (Unknown if no annotation.)
-    annotated_ty: Type<'db>,
-}
-
-impl<'db> Parameter<'db> {
-    fn from_node(
-        db: &'db dyn Db,
-        definition: Definition<'db>,
-        parameter: &'db ast::Parameter,
-    ) -> Self {
-        Parameter {
-            name: Some(parameter.name.id.clone()),
-            annotated_ty: parameter
-                .annotation
-                .as_deref()
-                .map(|annotation| definition_expression_ty(db, definition, annotation))
-                .unwrap_or(Type::Unknown),
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::db::tests::TestDb;
-    use crate::program::{Program, SearchPathSettings};
-    use crate::python_version::PythonVersion;
-    use crate::types::{global_symbol, FunctionType};
-    use crate::ProgramSettings;
-    use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
-
-    pub(crate) fn setup_db() -> TestDb {
-        let db = TestDb::new();
-
-        let src_root = SystemPathBuf::from("/src");
-        db.memory_file_system()
-            .create_directory_all(&src_root)
-            .unwrap();
-
-        Program::from_settings(
-            &db,
-            &ProgramSettings {
-                target_version: PythonVersion::default(),
-                search_paths: SearchPathSettings::new(src_root),
-            },
-        )
-        .expect("Valid search path settings");
-
-        db
-    }
-
-    #[track_caller]
-    fn get_function_f<'db>(db: &'db TestDb, file: &'static str) -> FunctionType<'db> {
-        let module = ruff_db::files::system_path_to_file(db, file).unwrap();
-        global_symbol(db, module, "f")
-            .expect_type()
-            .expect_function_literal()
-    }
-
-    #[track_caller]
-    fn assert_param_with_default<'db>(
-        db: &'db TestDb,
-        param_with_default: &ParameterWithDefault<'db>,
-        expected_name: &'static str,
-        expected_annotation_ty_display: &'static str,
-        expected_default_ty_display: Option<&'static str>,
-    ) {
-        assert_eq!(
-            param_with_default
-                .default_ty
-                .map(|ty| ty.display(db).to_string()),
-            expected_default_ty_display.map(ToString::to_string)
-        );
-        assert_param(
-            db,
-            &param_with_default.parameter,
-            expected_name,
-            expected_annotation_ty_display,
-        );
-    }
-
-    #[track_caller]
-    fn assert_param<'db>(
-        db: &'db TestDb,
-        param: &Parameter<'db>,
-        expected_name: &'static str,
-        expected_annotation_ty_display: &'static str,
-    ) {
-        assert_eq!(param.name.as_ref().unwrap(), expected_name);
-        assert_eq!(
-            param.annotated_ty.display(db).to_string(),
-            expected_annotation_ty_display
-        );
-    }
-
-    #[test]
-    fn empty() {
-        let mut db = setup_db();
-        db.write_dedented("/src/a.py", "def f(): ...").unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let sig = func.internal_signature(&db);
-
-        assert_eq!(sig.return_ty.display(&db).to_string(), "Unknown");
-        let params = sig.parameters;
-        assert!(params.positional_only.is_empty());
-        assert!(params.positional_or_keyword.is_empty());
-        assert!(params.variadic.is_none());
-        assert!(params.keyword_only.is_empty());
-        assert!(params.keywords.is_none());
-    }
-
-    #[test]
-    #[allow(clippy::many_single_char_names)]
-    fn full() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.py",
-            "
-            def f(a, b: int, c = 1, d: int = 2, /,
-                  e = 3, f: Literal[4] = 4, *args: object,
-                  g = 5, h: Literal[6] = 6, **kwargs: str) -> bytes: ...
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let sig = func.internal_signature(&db);
-
-        assert_eq!(sig.return_ty.display(&db).to_string(), "bytes");
-        let params = sig.parameters;
-        let [a, b, c, d] = &params.positional_only[..] else {
-            panic!("expected four positional-only parameters");
-        };
-        let [e, f] = &params.positional_or_keyword[..] else {
-            panic!("expected two positional-or-keyword parameters");
-        };
-        let Some(args) = params.variadic else {
-            panic!("expected a variadic parameter");
-        };
-        let [g, h] = &params.keyword_only[..] else {
-            panic!("expected two keyword-only parameters");
-        };
-        let Some(kwargs) = params.keywords else {
-            panic!("expected a kwargs parameter");
-        };
-
-        assert_param_with_default(&db, a, "a", "Unknown", None);
-        assert_param_with_default(&db, b, "b", "int", None);
-        assert_param_with_default(&db, c, "c", "Unknown", Some("Literal[1]"));
-        assert_param_with_default(&db, d, "d", "int", Some("Literal[2]"));
-        assert_param_with_default(&db, e, "e", "Unknown", Some("Literal[3]"));
-        assert_param_with_default(&db, f, "f", "Literal[4]", Some("Literal[4]"));
-        assert_param_with_default(&db, g, "g", "Unknown", Some("Literal[5]"));
-        assert_param_with_default(&db, h, "h", "Literal[6]", Some("Literal[6]"));
-        assert_param(&db, &args, "args", "object");
-        assert_param(&db, &kwargs, "kwargs", "str");
-    }
-
-    #[test]
-    fn not_deferred() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.py",
-            "
-            class A: ...
-            class B: ...
-
-            alias = A
-
-            def f(a: alias): ...
-
-            alias = B
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let sig = func.internal_signature(&db);
-
-        let [a] = &sig.parameters.positional_or_keyword[..] else {
-            panic!("expected one positional-or-keyword parameter");
-        };
-        // Parameter resolution not deferred; we should see A not B
-        assert_param_with_default(&db, a, "a", "A", None);
-    }
-
-    #[test]
-    fn deferred_in_stub() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.pyi",
-            "
-            class A: ...
-            class B: ...
-
-            alias = A
-
-            def f(a: alias): ...
-
-            alias = B
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.pyi");
-
-        let sig = func.internal_signature(&db);
-
-        let [a] = &sig.parameters.positional_or_keyword[..] else {
-            panic!("expected one positional-or-keyword parameter");
-        };
-        // Parameter resolution deferred; we should see B
-        assert_param_with_default(&db, a, "a", "B", None);
-    }
-
-    #[test]
-    fn generic_not_deferred() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.py",
-            "
-            class A: ...
-            class B: ...
-
-            alias = A
-
-            def f[T](a: alias, b: T) -> T: ...
-
-            alias = B
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let sig = func.internal_signature(&db);
-
-        let [a, b] = &sig.parameters.positional_or_keyword[..] else {
-            panic!("expected two positional-or-keyword parameters");
-        };
-        // TODO resolution should not be deferred; we should see A not B
-        assert_param_with_default(&db, a, "a", "B", None);
-        assert_param_with_default(&db, b, "b", "T", None);
-    }
-
-    #[test]
-    fn generic_deferred_in_stub() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.pyi",
-            "
-            class A: ...
-            class B: ...
-
-            alias = A
-
-            def f[T](a: alias, b: T) -> T: ...
-
-            alias = B
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.pyi");
-
-        let sig = func.internal_signature(&db);
-
-        let [a, b] = &sig.parameters.positional_or_keyword[..] else {
-            panic!("expected two positional-or-keyword parameters");
-        };
-        // Parameter resolution deferred; we should see B
-        assert_param_with_default(&db, a, "a", "B", None);
-        assert_param_with_default(&db, b, "b", "T", None);
-    }
-
-    #[test]
-    fn external_signature_no_decorator() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.py",
-            "
-            def f(a: int) -> int: ...
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let expected_sig = func.internal_signature(&db);
-
-        // With no decorators, internal and external signature are the same
-        assert_eq!(func.signature(&db), &expected_sig);
-    }
-
-    #[test]
-    fn external_signature_decorated() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/a.py",
-            "
-            def deco(func): ...
-
-            @deco
-            def f(a: int) -> int: ...
-            ",
-        )
-        .unwrap();
-        let func = get_function_f(&db, "/src/a.py");
-
-        let expected_sig = Signature::todo();
-
-        // With no decorators, internal and external signature are the same
-        assert_eq!(func.signature(&db), &expected_sig);
-    }
-}

crates/red_knot_python_semantic/src/types/string_annotation.rs

@@ -1,77 +0,0 @@
-use ruff_db::files::File;
-use ruff_db::source::source_text;
-use ruff_python_ast::str::raw_contents;
-use ruff_python_ast::{self as ast, ModExpression, StringFlags};
-use ruff_python_parser::{parse_expression_range, Parsed};
-use ruff_text_size::Ranged;
-
-use crate::types::diagnostic::{TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
-use crate::Db;
-
-type AnnotationParseResult = Result<Parsed<ModExpression>, TypeCheckDiagnostics>;
-
-/// Parses the given expression as a string annotation.
-pub(crate) fn parse_string_annotation(
-    db: &dyn Db,
-    file: File,
-    string_expr: &ast::ExprStringLiteral,
-) -> AnnotationParseResult {
-    let _span = tracing::trace_span!("parse_string_annotation", string=?string_expr.range(), file=%file.path(db)).entered();
-
-    let source = source_text(db.upcast(), file);
-    let node_text = &source[string_expr.range()];
-    let mut diagnostics = TypeCheckDiagnosticsBuilder::new(db, file);
-
-    if let [string_literal] = string_expr.value.as_slice() {
-        let prefix = string_literal.flags.prefix();
-        if prefix.is_raw() {
-            diagnostics.add(
-                string_literal.into(),
-                "annotation-raw-string",
-                format_args!("Type expressions cannot use raw string literal"),
-            );
-        // Compare the raw contents (without quotes) of the expression with the parsed contents
-        // contained in the string literal.
-        } else if raw_contents(node_text)
-            .is_some_and(|raw_contents| raw_contents == string_literal.as_str())
-        {
-            let range_excluding_quotes = string_literal
-                .range()
-                .add_start(string_literal.flags.opener_len())
-                .sub_end(string_literal.flags.closer_len());
-
-            // TODO: Support multiline strings like:
-            // ```py
-            // x: """
-            //     int
-            //     | float
-            // """ = 1
-            // ```
-            match parse_expression_range(source.as_str(), range_excluding_quotes) {
-                Ok(parsed) => return Ok(parsed),
-                Err(parse_error) => diagnostics.add(
-                    string_literal.into(),
-                    "forward-annotation-syntax-error",
-                    format_args!("Syntax error in forward annotation: {}", parse_error.error),
-                ),
-            }
-        } else {
-            // The raw contents of the string doesn't match the parsed content. This could be the
-            // case for annotations that contain escape sequences.
-            diagnostics.add(
-                string_expr.into(),
-                "annotation-escape-character",
-                format_args!("Type expressions cannot contain escape characters"),
-            );
-        }
-    } else {
-        // String is implicitly concatenated.
-        diagnostics.add(
-            string_expr.into(),
-            "annotation-implicit-concat",
-            format_args!("Type expressions cannot span multiple string literals"),
-        );
-    }
-
-    Err(diagnostics.finish())
-}

crates/red_knot_python_semantic/src/types/unpacker.rs

@@ -1,142 +0,0 @@
-use std::borrow::Cow;
-
-use ruff_db::files::File;
-use ruff_python_ast::{self as ast, AnyNodeRef};
-use rustc_hash::FxHashMap;
-
-use crate::semantic_index::ast_ids::{HasScopedExpressionId, ScopedExpressionId};
-use crate::semantic_index::symbol::ScopeId;
-use crate::types::{Type, TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
-use crate::Db;
-
-/// Unpacks the value expression type to their respective targets.
-pub(crate) struct Unpacker<'db> {
-    db: &'db dyn Db,
-    targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnosticsBuilder<'db>,
-}
-
-impl<'db> Unpacker<'db> {
-    pub(crate) fn new(db: &'db dyn Db, file: File) -> Self {
-        Self {
-            db,
-            targets: FxHashMap::default(),
-            diagnostics: TypeCheckDiagnosticsBuilder::new(db, file),
-        }
-    }
-
-    pub(crate) fn unpack(&mut self, target: &ast::Expr, value_ty: Type<'db>, scope: ScopeId<'db>) {
-        match target {
-            ast::Expr::Name(target_name) => {
-                self.targets
-                    .insert(target_name.scoped_expression_id(self.db, scope), value_ty);
-            }
-            ast::Expr::Starred(ast::ExprStarred { value, .. }) => {
-                self.unpack(value, value_ty, scope);
-            }
-            ast::Expr::List(ast::ExprList { elts, .. })
-            | ast::Expr::Tuple(ast::ExprTuple { elts, .. }) => match value_ty {
-                Type::Tuple(tuple_ty) => {
-                    let starred_index = elts.iter().position(ast::Expr::is_starred_expr);
-
-                    let element_types = if let Some(starred_index) = starred_index {
-                        if tuple_ty.len(self.db) >= elts.len() - 1 {
-                            let mut element_types = Vec::with_capacity(elts.len());
-                            element_types.extend_from_slice(
-                                // SAFETY: Safe because of the length check above.
-                                &tuple_ty.elements(self.db)[..starred_index],
-                            );
-
-                            // E.g., in `(a, *b, c, d) = ...`, the index of starred element `b`
-                            // is 1 and the remaining elements after that are 2.
-                            let remaining = elts.len() - (starred_index + 1);
-                            // This index represents the type of the last element that belongs
-                            // to the starred expression, in an exclusive manner.
-                            let starred_end_index = tuple_ty.len(self.db) - remaining;
-                            // SAFETY: Safe because of the length check above.
-                            let _starred_element_types =
-                                &tuple_ty.elements(self.db)[starred_index..starred_end_index];
-                            // TODO: Combine the types into a list type. If the
-                            // starred_element_types is empty, then it should be `List[Any]`.
-                            // combine_types(starred_element_types);
-                            element_types.push(Type::Todo);
-
-                            element_types.extend_from_slice(
-                                // SAFETY: Safe because of the length check above.
-                                &tuple_ty.elements(self.db)[starred_end_index..],
-                            );
-                            Cow::Owned(element_types)
-                        } else {
-                            let mut element_types = tuple_ty.elements(self.db).to_vec();
-                            // Subtract 1 to insert the starred expression type at the correct
-                            // index.
-                            element_types.resize(elts.len() - 1, Type::Unknown);
-                            // TODO: This should be `list[Unknown]`
-                            element_types.insert(starred_index, Type::Todo);
-                            Cow::Owned(element_types)
-                        }
-                    } else {
-                        Cow::Borrowed(tuple_ty.elements(self.db).as_ref())
-                    };
-
-                    for (index, element) in elts.iter().enumerate() {
-                        self.unpack(
-                            element,
-                            element_types.get(index).copied().unwrap_or(Type::Unknown),
-                            scope,
-                        );
-                    }
-                }
-                Type::StringLiteral(string_literal_ty) => {
-                    // Deconstruct the string literal to delegate the inference back to the
-                    // tuple type for correct handling of starred expressions. We could go
-                    // further and deconstruct to an array of `StringLiteral` with each
-                    // individual character, instead of just an array of `LiteralString`, but
-                    // there would be a cost and it's not clear that it's worth it.
-                    let value_ty = Type::tuple(
-                        self.db,
-                        &vec![Type::LiteralString; string_literal_ty.len(self.db)],
-                    );
-                    self.unpack(target, value_ty, scope);
-                }
-                _ => {
-                    let value_ty = if value_ty.is_literal_string() {
-                        Type::LiteralString
-                    } else {
-                        value_ty
-                            .iterate(self.db)
-                            .unwrap_with_diagnostic(AnyNodeRef::from(target), &mut self.diagnostics)
-                    };
-                    for element in elts {
-                        self.unpack(element, value_ty, scope);
-                    }
-                }
-            },
-            _ => {}
-        }
-    }
-
-    pub(crate) fn finish(mut self) -> UnpackResult<'db> {
-        self.targets.shrink_to_fit();
-        UnpackResult {
-            diagnostics: self.diagnostics.finish(),
-            targets: self.targets,
-        }
-    }
-}
-
-#[derive(Debug, Default, PartialEq, Eq)]
-pub(crate) struct UnpackResult<'db> {
-    targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnostics,
-}
-
-impl<'db> UnpackResult<'db> {
-    pub(crate) fn get(&self, expr_id: ScopedExpressionId) -> Option<Type<'db>> {
-        self.targets.get(&expr_id).copied()
-    }
-
-    pub(crate) fn diagnostics(&self) -> &TypeCheckDiagnostics {
-        &self.diagnostics
-    }
-}

crates/red_knot_python_semantic/src/unpack.rs

@@ -1,55 +0,0 @@
-use ruff_db::files::File;
-use ruff_python_ast::{self as ast};
-
-use crate::ast_node_ref::AstNodeRef;
-use crate::semantic_index::expression::Expression;
-use crate::semantic_index::symbol::{FileScopeId, ScopeId};
-use crate::Db;
-
-/// This ingredient represents a single unpacking.
-///
-/// This is required to make use of salsa to cache the complete unpacking of multiple variables
-/// involved. It allows us to:
-/// 1. Avoid doing structural match multiple times for each definition
-/// 2. Avoid highlighting the same error multiple times
-///
-/// ## Module-local type
-/// This type should not be used as part of any cross-module API because
-/// it holds a reference to the AST node. Range-offset changes
-/// then propagate through all usages, and deserialization requires
-/// reparsing the entire module.
-///
-/// E.g. don't use this type in:
-///
-/// * a return type of a cross-module query
-/// * a field of a type that is a return type of a cross-module query
-/// * an argument of a cross-module query
-#[salsa::tracked]
-pub(crate) struct Unpack<'db> {
-    #[id]
-    pub(crate) file: File,
-
-    #[id]
-    pub(crate) file_scope: FileScopeId,
-
-    /// The target expression that is being unpacked. For example, in `(a, b) = (1, 2)`, the target
-    /// expression is `(a, b)`.
-    #[no_eq]
-    #[return_ref]
-    pub(crate) target: AstNodeRef<ast::Expr>,
-
-    /// The ingredient representing the value expression of the unpacking. For example, in
-    /// `(a, b) = (1, 2)`, the value expression is `(1, 2)`.
-    #[no_eq]
-    pub(crate) value: Expression<'db>,
-
-    #[no_eq]
-    count: countme::Count<Unpack<'static>>,
-}
-
-impl<'db> Unpack<'db> {
-    /// Returns the scope where the unpacking is happening.
-    pub(crate) fn scope(self, db: &'db dyn Db) -> ScopeId<'db> {
-        self.file_scope(db).to_scope_id(db, self.file(db))
-    }
-}

crates/red_knot_python_semantic/tests/mdtest.rs

@@ -1,7 +1,6 @@
-use std::ffi::OsStr;
-use std::path::Path;
-
 use dir_test::{dir_test, Fixture};
+use red_knot_test::run;
+use std::path::Path;
 
 /// See `crates/red_knot_test/README.md` for documentation on these tests.
 #[dir_test(
@@ -10,16 +9,16 @@ use dir_test::{dir_test, Fixture};
 )]
 #[allow(clippy::needless_pass_by_value)]
 fn mdtest(fixture: Fixture<&str>) {
-    let fixture_path = Path::new(fixture.path());
-    let crate_dir = Path::new(env!("CARGO_MANIFEST_DIR"));
-    let workspace_root = crate_dir.parent().and_then(Path::parent).unwrap();
+    let path = fixture.path();
 
-    let long_title = fixture_path
-        .strip_prefix(workspace_root)
-        .unwrap()
-        .to_str()
+    let crate_dir = Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("resources/mdtest")
+        .canonicalize()
         .unwrap();
-    let short_title = fixture_path.file_name().and_then(OsStr::to_str).unwrap();
 
-    red_knot_test::run(fixture_path, long_title, short_title);
+    let relative_path = path
+        .strip_prefix(crate_dir.to_str().unwrap())
+        .unwrap_or(path);
+
+    run(Path::new(path), relative_path);
 }

crates/red_knot_server/src/edit.rs

@@ -6,7 +6,7 @@ mod text_document;
 
 use lsp_types::{PositionEncodingKind, Url};
 pub use notebook::NotebookDocument;
-pub(crate) use range::{RangeExt, ToRangeExt};
+pub(crate) use range::RangeExt;
 pub(crate) use text_document::DocumentVersion;
 pub use text_document::TextDocument;
 

crates/red_knot_server/src/edit/range.rs

@@ -1,32 +1,13 @@
-use super::notebook;
 use super::PositionEncoding;
-use lsp_types as types;
-use ruff_notebook::NotebookIndex;
+use ruff_source_file::LineIndex;
 use ruff_source_file::OneIndexed;
-use ruff_source_file::{LineIndex, SourceLocation};
 use ruff_text_size::{TextRange, TextSize};
 
-pub(crate) struct NotebookRange {
-    pub(crate) cell: notebook::CellId,
-    pub(crate) range: types::Range,
-}
-
 pub(crate) trait RangeExt {
     fn to_text_range(&self, text: &str, index: &LineIndex, encoding: PositionEncoding)
         -> TextRange;
 }
 
-pub(crate) trait ToRangeExt {
-    fn to_range(&self, text: &str, index: &LineIndex, encoding: PositionEncoding) -> types::Range;
-    fn to_notebook_range(
-        &self,
-        text: &str,
-        source_index: &LineIndex,
-        notebook_index: &NotebookIndex,
-        encoding: PositionEncoding,
-    ) -> NotebookRange;
-}
-
 fn u32_index_to_usize(index: u32) -> usize {
     usize::try_from(index).expect("u32 fits in usize")
 }
@@ -94,61 +75,6 @@ impl RangeExt for lsp_types::Range {
     }
 }
 
-impl ToRangeExt for TextRange {
-    fn to_range(&self, text: &str, index: &LineIndex, encoding: PositionEncoding) -> types::Range {
-        types::Range {
-            start: source_location_to_position(&offset_to_source_location(
-                self.start(),
-                text,
-                index,
-                encoding,
-            )),
-            end: source_location_to_position(&offset_to_source_location(
-                self.end(),
-                text,
-                index,
-                encoding,
-            )),
-        }
-    }
-
-    fn to_notebook_range(
-        &self,
-        text: &str,
-        source_index: &LineIndex,
-        notebook_index: &NotebookIndex,
-        encoding: PositionEncoding,
-    ) -> NotebookRange {
-        let start = offset_to_source_location(self.start(), text, source_index, encoding);
-        let mut end = offset_to_source_location(self.end(), text, source_index, encoding);
-        let starting_cell = notebook_index.cell(start.row);
-
-        // weird edge case here - if the end of the range is where the newline after the cell got added (making it 'out of bounds')
-        // we need to move it one character back (which should place it at the end of the last line).
-        // we test this by checking if the ending offset is in a different (or nonexistent) cell compared to the cell of the starting offset.
-        if notebook_index.cell(end.row) != starting_cell {
-            end.row = end.row.saturating_sub(1);
-            end.column = offset_to_source_location(
-                self.end().checked_sub(1.into()).unwrap_or_default(),
-                text,
-                source_index,
-                encoding,
-            )
-            .column;
-        }
-
-        let start = source_location_to_position(&notebook_index.translate_location(&start));
-        let end = source_location_to_position(&notebook_index.translate_location(&end));
-
-        NotebookRange {
-            cell: starting_cell
-                .map(OneIndexed::to_zero_indexed)
-                .unwrap_or_default(),
-            range: types::Range { start, end },
-        }
-    }
-}
-
 /// Converts a UTF-16 code unit offset for a given line into a UTF-8 column number.
 fn utf8_column_offset(utf16_code_unit_offset: u32, line: &str) -> TextSize {
     let mut utf8_code_unit_offset = TextSize::new(0);
@@ -170,46 +96,3 @@ fn utf8_column_offset(utf16_code_unit_offset: u32, line: &str) -> TextSize {
 
     utf8_code_unit_offset
 }
-
-fn offset_to_source_location(
-    offset: TextSize,
-    text: &str,
-    index: &LineIndex,
-    encoding: PositionEncoding,
-) -> SourceLocation {
-    match encoding {
-        PositionEncoding::UTF8 => {
-            let row = index.line_index(offset);
-            let column = offset - index.line_start(row, text);
-
-            SourceLocation {
-                column: OneIndexed::from_zero_indexed(column.to_usize()),
-                row,
-            }
-        }
-        PositionEncoding::UTF16 => {
-            let row = index.line_index(offset);
-
-            let column = if index.is_ascii() {
-                (offset - index.line_start(row, text)).to_usize()
-            } else {
-                let up_to_line = &text[TextRange::new(index.line_start(row, text), offset)];
-                up_to_line.encode_utf16().count()
-            };
-
-            SourceLocation {
-                column: OneIndexed::from_zero_indexed(column),
-                row,
-            }
-        }
-        PositionEncoding::UTF32 => index.source_location(offset, text),
-    }
-}
-
-fn source_location_to_position(location: &SourceLocation) -> types::Position {
-    types::Position {
-        line: u32::try_from(location.row.to_zero_indexed()).expect("row usize fits in u32"),
-        character: u32::try_from(location.column.to_zero_indexed())
-            .expect("character usize fits in u32"),
-    }
-}

crates/red_knot_server/src/server/api/requests/diagnostic.rs

@@ -3,17 +3,15 @@ use std::borrow::Cow;
 use lsp_types::request::DocumentDiagnosticRequest;
 use lsp_types::{
     Diagnostic, DiagnosticSeverity, DocumentDiagnosticParams, DocumentDiagnosticReport,
-    DocumentDiagnosticReportResult, FullDocumentDiagnosticReport, NumberOrString, Range,
+    DocumentDiagnosticReportResult, FullDocumentDiagnosticReport, Position, Range,
     RelatedFullDocumentDiagnosticReport, Url,
 };
 
-use crate::edit::ToRangeExt;
+use red_knot_workspace::db::RootDatabase;
+
 use crate::server::api::traits::{BackgroundDocumentRequestHandler, RequestHandler};
 use crate::server::{client::Notifier, Result};
 use crate::session::DocumentSnapshot;
-use red_knot_workspace::db::{Db, RootDatabase};
-use ruff_db::diagnostic::Severity;
-use ruff_db::source::{line_index, source_text};
 
 pub(crate) struct DocumentDiagnosticRequestHandler;
 
@@ -66,37 +64,36 @@ fn compute_diagnostics(snapshot: &DocumentSnapshot, db: &RootDatabase) -> Vec<Di
     diagnostics
         .as_slice()
         .iter()
-        .map(|message| to_lsp_diagnostic(db, message, snapshot.encoding()))
+        .map(|message| to_lsp_diagnostic(message))
         .collect()
 }
 
-fn to_lsp_diagnostic(
-    db: &dyn Db,
-    diagnostic: &dyn ruff_db::diagnostic::Diagnostic,
-    encoding: crate::PositionEncoding,
-) -> Diagnostic {
-    let range = if let Some(range) = diagnostic.range() {
-        let index = line_index(db.upcast(), diagnostic.file());
-        let source = source_text(db.upcast(), diagnostic.file());
+fn to_lsp_diagnostic(message: &str) -> Diagnostic {
+    let words = message.split(':').collect::<Vec<_>>();
 
-        range.to_range(&source, &index, encoding)
-    } else {
-        Range::default()
-    };
-
-    let severity = match diagnostic.severity() {
-        Severity::Info => DiagnosticSeverity::INFORMATION,
-        Severity::Error => DiagnosticSeverity::ERROR,
+    let (range, message) = match words.as_slice() {
+        [_, _, line, column, message] | [_, line, column, message] => {
+            let line = line.parse::<u32>().unwrap_or_default().saturating_sub(1);
+            let column = column.parse::<u32>().unwrap_or_default();
+            (
+                Range::new(
+                    Position::new(line, column.saturating_sub(1)),
+                    Position::new(line, column),
+                ),
+                message.trim(),
+            )
+        }
+        _ => (Range::default(), message),
     };
 
     Diagnostic {
         range,
-        severity: Some(severity),
+        severity: Some(DiagnosticSeverity::ERROR),
         tags: None,
-        code: Some(NumberOrString::String(diagnostic.rule().to_string())),
+        code: None,
         code_description: None,
         source: Some("red-knot".into()),
-        message: diagnostic.message().into_owned(),
+        message: message.to_string(),
         related_information: None,
         data: None,
     }

crates/red_knot_server/src/session.rs

@@ -68,7 +68,7 @@ impl Session {
             let system = LSPSystem::new(index.clone());
 
             // TODO(dhruvmanila): Get the values from the client settings
-            let metadata = WorkspaceMetadata::discover(system_path, &system, None)?;
+            let metadata = WorkspaceMetadata::from_path(system_path, &system, None)?;
             // TODO(micha): Handle the case where the program settings are incorrect more gracefully.
             workspaces.insert(path, RootDatabase::new(metadata, system)?);
         }

crates/red_knot_server/src/system.rs

@@ -7,8 +7,8 @@ use lsp_types::Url;
 use ruff_db::file_revision::FileRevision;
 use ruff_db::system::walk_directory::WalkDirectoryBuilder;
 use ruff_db::system::{
-    DirectoryEntry, FileType, GlobError, Metadata, OsSystem, PatternError, Result, System,
-    SystemPath, SystemPathBuf, SystemVirtualPath, SystemVirtualPathBuf,
+    DirectoryEntry, FileType, Metadata, OsSystem, Result, System, SystemPath, SystemPathBuf,
+    SystemVirtualPath, SystemVirtualPathBuf,
 };
 use ruff_notebook::{Notebook, NotebookError};
 
@@ -198,16 +198,6 @@ impl System for LSPSystem {
         self.os_system.walk_directory(path)
     }
 
-    fn glob(
-        &self,
-        pattern: &str,
-    ) -> std::result::Result<
-        Box<dyn Iterator<Item = std::result::Result<SystemPathBuf, GlobError>>>,
-        PatternError,
-    > {
-        self.os_system.glob(pattern)
-    }
-
     fn as_any(&self) -> &dyn Any {
         self
     }

crates/red_knot_test/src/diagnostic.rs

@@ -2,8 +2,8 @@
 //!
 //! We don't assume that we will get the diagnostics in source order.
 
-use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::{LineIndex, OneIndexed};
+use ruff_text_size::Ranged;
 use std::ops::{Deref, Range};
 
 /// All diagnostics for one embedded Python file, sorted and grouped by start line number.
@@ -19,17 +19,13 @@ pub(crate) struct SortedDiagnostics<T> {
 
 impl<T> SortedDiagnostics<T>
 where
-    T: Diagnostic,
+    T: Ranged + Clone,
 {
     pub(crate) fn new(diagnostics: impl IntoIterator<Item = T>, line_index: &LineIndex) -> Self {
         let mut diagnostics: Vec<_> = diagnostics
             .into_iter()
             .map(|diagnostic| DiagnosticWithLine {
-                line_number: diagnostic
-                    .range()
-                    .map_or(OneIndexed::from_zero_indexed(0), |range| {
-                        line_index.line_index(range.start())
-                    }),
+                line_number: line_index.line_index(diagnostic.start()),
                 diagnostic,
             })
             .collect();
@@ -98,7 +94,7 @@ pub(crate) struct LineDiagnosticsIterator<'a, T> {
 
 impl<'a, T> Iterator for LineDiagnosticsIterator<'a, T>
 where
-    T: Diagnostic,
+    T: Ranged + Clone,
 {
     type Item = LineDiagnostics<'a, T>;
 
@@ -114,7 +110,7 @@ where
     }
 }
 
-impl<T> std::iter::FusedIterator for LineDiagnosticsIterator<'_, T> where T: Diagnostic {}
+impl<T> std::iter::FusedIterator for LineDiagnosticsIterator<'_, T> where T: Clone + Ranged {}
 
 /// All diagnostics that start on a single line of source code in one embedded Python file.
 #[derive(Debug)]
@@ -143,14 +139,11 @@ struct DiagnosticWithLine<T> {
 #[cfg(test)]
 mod tests {
     use crate::db::Db;
-    use crate::diagnostic::Diagnostic;
-    use ruff_db::diagnostic::Severity;
-    use ruff_db::files::{system_path_to_file, File};
+    use ruff_db::files::system_path_to_file;
     use ruff_db::source::line_index;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
     use ruff_source_file::OneIndexed;
     use ruff_text_size::{TextRange, TextSize};
-    use std::borrow::Cow;
 
     #[test]
     fn sort_and_group() {
@@ -159,18 +152,13 @@ mod tests {
         let file = system_path_to_file(&db, "/src/test.py").unwrap();
         let lines = line_index(&db, file);
 
-        let ranges = [
+        let ranges = vec![
             TextRange::new(TextSize::new(0), TextSize::new(1)),
             TextRange::new(TextSize::new(5), TextSize::new(10)),
             TextRange::new(TextSize::new(1), TextSize::new(7)),
         ];
 
-        let diagnostics: Vec<_> = ranges
-            .into_iter()
-            .map(|range| DummyDiagnostic { range, file })
-            .collect();
-
-        let sorted = super::SortedDiagnostics::new(diagnostics, &lines);
+        let sorted = super::SortedDiagnostics::new(&ranges, &lines);
         let grouped = sorted.iter_lines().collect::<Vec<_>>();
 
         let [line1, line2] = &grouped[..] else {
@@ -182,32 +170,4 @@ mod tests {
         assert_eq!(line2.line_number, OneIndexed::from_zero_indexed(1));
         assert_eq!(line2.diagnostics.len(), 1);
     }
-
-    #[derive(Debug)]
-    struct DummyDiagnostic {
-        range: TextRange,
-        file: File,
-    }
-
-    impl Diagnostic for DummyDiagnostic {
-        fn rule(&self) -> &str {
-            "dummy"
-        }
-
-        fn message(&self) -> Cow<str> {
-            "dummy".into()
-        }
-
-        fn file(&self) -> File {
-            self.file
-        }
-
-        fn range(&self) -> Option<TextRange> {
-            Some(self.range)
-        }
-
-        fn severity(&self) -> Severity {
-            Severity::Error
-        }
-    }
 }

crates/red_knot_test/src/lib.rs

@@ -1,7 +1,6 @@
 use colored::Colorize;
 use parser as test_parser;
 use red_knot_python_semantic::types::check_types;
-use ruff_db::diagnostic::{Diagnostic, ParseDiagnostic};
 use ruff_db::files::{system_path_to_file, File, Files};
 use ruff_db::parsed::parsed_module;
 use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
@@ -19,9 +18,9 @@ mod parser;
 ///
 /// Panic on test failure, and print failure details.
 #[allow(clippy::print_stdout)]
-pub fn run(path: &Path, long_title: &str, short_title: &str) {
+pub fn run(path: &Path, title: &str) {
     let source = std::fs::read_to_string(path).unwrap();
-    let suite = match test_parser::parse(short_title, &source) {
+    let suite = match test_parser::parse(title, &source) {
         Ok(suite) => suite,
         Err(err) => {
             panic!("Error parsing `{}`: {err}", path.to_str().unwrap())
@@ -49,8 +48,8 @@ pub fn run(path: &Path, long_title: &str, short_title: &str) {
                     for failure in failures {
                         let absolute_line_number =
                             backtick_line.checked_add(relative_line_number).unwrap();
-                        let line_info = format!("{long_title}:{absolute_line_number}").cyan();
-                        println!("  {line_info} {failure}");
+                        let line_info = format!("{title}:{absolute_line_number}").cyan();
+                        println!("    {line_info} {failure}");
                     }
                 }
             }
@@ -88,24 +87,16 @@ fn run_test(db: &mut db::Db, test: &parser::MarkdownTest) -> Result<(), Failures
         .filter_map(|test_file| {
             let parsed = parsed_module(db, test_file.file);
 
-            let mut diagnostics: Vec<Box<_>> = parsed
-                .errors()
-                .iter()
-                .cloned()
-                .map(|error| {
-                    let diagnostic: Box<dyn Diagnostic> =
-                        Box::new(ParseDiagnostic::new(test_file.file, error));
-                    diagnostic
-                })
-                .collect();
+            // TODO allow testing against code with syntax errors
+            assert!(
+                parsed.errors().is_empty(),
+                "Python syntax errors in {}, {}: {:?}",
+                test.name(),
+                test_file.file.path(db),
+                parsed.errors()
+            );
 
-            let type_diagnostics = check_types(db, test_file.file);
-            diagnostics.extend(type_diagnostics.into_iter().map(|diagnostic| {
-                let diagnostic: Box<dyn Diagnostic> = Box::new((*diagnostic).clone());
-                diagnostic
-            }));
-
-            match matcher::match_file(db, test_file.file, diagnostics) {
+            match matcher::match_file(db, test_file.file, check_types(db, test_file.file)) {
                 Ok(()) => None,
                 Err(line_failures) => Some(FileFailures {
                     backtick_offset: test_file.backtick_offset,

crates/red_knot_test/src/matcher.rs

@@ -1,15 +1,17 @@
-//! Match [`Diagnostic`]s against [`Assertion`]s and produce test failure messages for any
+//! Match [`TypeCheckDiagnostic`]s against [`Assertion`]s and produce test failure messages for any
 //! mismatches.
 use crate::assertion::{Assertion, ErrorAssertion, InlineFileAssertions};
 use crate::db::Db;
 use crate::diagnostic::SortedDiagnostics;
 use colored::Colorize;
-use ruff_db::diagnostic::Diagnostic;
+use red_knot_python_semantic::types::TypeCheckDiagnostic;
 use ruff_db::files::File;
 use ruff_db::source::{line_index, source_text, SourceText};
 use ruff_source_file::{LineIndex, OneIndexed};
+use ruff_text_size::Ranged;
 use std::cmp::Ordering;
 use std::ops::Range;
+use std::sync::Arc;
 
 #[derive(Debug, Default)]
 pub(super) struct FailuresByLine {
@@ -53,7 +55,7 @@ pub(super) fn match_file<T>(
     diagnostics: impl IntoIterator<Item = T>,
 ) -> Result<(), FailuresByLine>
 where
-    T: Diagnostic,
+    T: Diagnostic + Clone,
 {
     // Parse assertions from comments in the file, and get diagnostics from the file; both
     // ordered by line number.
@@ -124,6 +126,22 @@ where
     }
 }
 
+pub(super) trait Diagnostic: Ranged {
+    fn rule(&self) -> &str;
+
+    fn message(&self) -> &str;
+}
+
+impl Diagnostic for Arc<TypeCheckDiagnostic> {
+    fn rule(&self) -> &str {
+        self.as_ref().rule()
+    }
+
+    fn message(&self) -> &str {
+        self.as_ref().message()
+    }
+}
+
 trait Unmatched {
     fn unmatched(&self) -> String;
 }
@@ -235,15 +253,10 @@ impl Matcher {
         }
     }
 
-    fn column<T: Diagnostic>(&self, diagnostic: &T) -> OneIndexed {
-        diagnostic
-            .range()
-            .map(|range| {
-                self.line_index
-                    .source_location(range.start(), &self.source)
-                    .column
-            })
-            .unwrap_or(OneIndexed::from_zero_indexed(0))
+    fn column<T: Ranged>(&self, ranged: &T) -> OneIndexed {
+        self.line_index
+            .source_location(ranged.start(), &self.source)
+            .column
     }
 
     /// Check if `assertion` matches any [`Diagnostic`]s in `unmatched`.
@@ -310,21 +323,20 @@ impl Matcher {
 #[cfg(test)]
 mod tests {
     use super::FailuresByLine;
-    use ruff_db::diagnostic::{Diagnostic, Severity};
-    use ruff_db::files::{system_path_to_file, File};
+    use ruff_db::files::system_path_to_file;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
     use ruff_python_trivia::textwrap::dedent;
     use ruff_source_file::OneIndexed;
-    use ruff_text_size::TextRange;
-    use std::borrow::Cow;
+    use ruff_text_size::{Ranged, TextRange};
 
-    struct ExpectedDiagnostic {
+    #[derive(Clone, Debug)]
+    struct TestDiagnostic {
         rule: &'static str,
         message: &'static str,
         range: TextRange,
     }
 
-    impl ExpectedDiagnostic {
+    impl TestDiagnostic {
         fn new(rule: &'static str, message: &'static str, offset: usize) -> Self {
             let offset: u32 = offset.try_into().unwrap();
             Self {
@@ -333,64 +345,32 @@ mod tests {
                 range: TextRange::new(offset.into(), (offset + 1).into()),
             }
         }
-
-        fn into_diagnostic(self, file: File) -> TestDiagnostic {
-            TestDiagnostic {
-                rule: self.rule,
-                message: self.message,
-                range: self.range,
-                file,
-            }
-        }
     }
 
-    #[derive(Debug)]
-    struct TestDiagnostic {
-        rule: &'static str,
-        message: &'static str,
-        range: TextRange,
-        file: File,
-    }
-
-    impl Diagnostic for TestDiagnostic {
+    impl super::Diagnostic for TestDiagnostic {
         fn rule(&self) -> &str {
             self.rule
         }
 
-        fn message(&self) -> Cow<str> {
-            self.message.into()
-        }
-
-        fn file(&self) -> File {
-            self.file
-        }
-
-        fn range(&self) -> Option<TextRange> {
-            Some(self.range)
-        }
-
-        fn severity(&self) -> Severity {
-            Severity::Error
+        fn message(&self) -> &str {
+            self.message
         }
     }
 
-    fn get_result(
-        source: &str,
-        diagnostics: Vec<ExpectedDiagnostic>,
-    ) -> Result<(), FailuresByLine> {
+    impl Ranged for TestDiagnostic {
+        fn range(&self) -> ruff_text_size::TextRange {
+            self.range
+        }
+    }
+
+    fn get_result(source: &str, diagnostics: Vec<TestDiagnostic>) -> Result<(), FailuresByLine> {
         colored::control::set_override(false);
 
         let mut db = crate::db::Db::setup(SystemPathBuf::from("/src"));
         db.write_file("/src/test.py", source).unwrap();
         let file = system_path_to_file(&db, "/src/test.py").unwrap();
 
-        super::match_file(
-            &db,
-            file,
-            diagnostics
-                .into_iter()
-                .map(|diagnostic| diagnostic.into_diagnostic(file)),
-        )
+        super::match_file(&db, file, diagnostics)
     }
 
     fn assert_fail(result: Result<(), FailuresByLine>, messages: &[(usize, &[&str])]) {
@@ -423,7 +403,7 @@ mod tests {
     fn revealed_match() {
         let result = get_result(
             "x # revealed: Foo",
-            vec![ExpectedDiagnostic::new(
+            vec![TestDiagnostic::new(
                 "revealed-type",
                 "Revealed type is `Foo`",
                 0,
@@ -437,7 +417,7 @@ mod tests {
     fn revealed_wrong_rule() {
         let result = get_result(
             "x # revealed: Foo",
-            vec![ExpectedDiagnostic::new(
+            vec![TestDiagnostic::new(
                 "not-revealed-type",
                 "Revealed type is `Foo`",
                 0,
@@ -460,11 +440,7 @@ mod tests {
     fn revealed_wrong_message() {
         let result = get_result(
             "x # revealed: Foo",
-            vec![ExpectedDiagnostic::new(
-                "revealed-type",
-                "Something else",
-                0,
-            )],
+            vec![TestDiagnostic::new("revealed-type", "Something else", 0)],
         );
 
         assert_fail(
@@ -491,8 +467,8 @@ mod tests {
         let result = get_result(
             "x # revealed: Foo",
             vec![
-                ExpectedDiagnostic::new("revealed-type", "Revealed type is `Foo`", 0),
-                ExpectedDiagnostic::new("undefined-reveal", "Doesn't matter", 0),
+                TestDiagnostic::new("revealed-type", "Revealed type is `Foo`", 0),
+                TestDiagnostic::new("undefined-reveal", "Doesn't matter", 0),
             ],
         );
 
@@ -503,11 +479,7 @@ mod tests {
     fn revealed_match_with_only_undefined() {
         let result = get_result(
             "x # revealed: Foo",
-            vec![ExpectedDiagnostic::new(
-                "undefined-reveal",
-                "Doesn't matter",
-                0,
-            )],
+            vec![TestDiagnostic::new("undefined-reveal", "Doesn't matter", 0)],
         );
 
         assert_fail(result, &[(0, &["unmatched assertion: revealed: Foo"])]);
@@ -518,8 +490,8 @@ mod tests {
         let result = get_result(
             "x # revealed: Foo",
             vec![
-                ExpectedDiagnostic::new("revealed-type", "Revealed type is `Bar`", 0),
-                ExpectedDiagnostic::new("undefined-reveal", "Doesn't matter", 0),
+                TestDiagnostic::new("revealed-type", "Revealed type is `Bar`", 0),
+                TestDiagnostic::new("undefined-reveal", "Doesn't matter", 0),
             ],
         );
 
@@ -540,8 +512,8 @@ mod tests {
         let result = get_result(
             "reveal_type(1)",
             vec![
-                ExpectedDiagnostic::new("undefined-reveal", "undefined reveal message", 0),
-                ExpectedDiagnostic::new("revealed-type", "Revealed type is `Literal[1]`", 12),
+                TestDiagnostic::new("undefined-reveal", "undefined reveal message", 0),
+                TestDiagnostic::new("revealed-type", "Revealed type is `Literal[1]`", 12),
             ],
         );
 
@@ -563,8 +535,8 @@ mod tests {
         let result = get_result(
             "reveal_type(1) # error: [something-else]",
             vec![
-                ExpectedDiagnostic::new("undefined-reveal", "undefined reveal message", 0),
-                ExpectedDiagnostic::new("revealed-type", "Revealed type is `Literal[1]`", 12),
+                TestDiagnostic::new("undefined-reveal", "undefined reveal message", 0),
+                TestDiagnostic::new("revealed-type", "Revealed type is `Literal[1]`", 12),
             ],
         );
 
@@ -593,7 +565,7 @@ mod tests {
     fn error_match_rule() {
         let result = get_result(
             "x # error: [some-rule]",
-            vec![ExpectedDiagnostic::new("some-rule", "Any message", 0)],
+            vec![TestDiagnostic::new("some-rule", "Any message", 0)],
         );
 
         assert_ok(&result);
@@ -603,7 +575,7 @@ mod tests {
     fn error_wrong_rule() {
         let result = get_result(
             "x # error: [some-rule]",
-            vec![ExpectedDiagnostic::new("anything", "Any message", 0)],
+            vec![TestDiagnostic::new("anything", "Any message", 0)],
         );
 
         assert_fail(
@@ -622,11 +594,7 @@ mod tests {
     fn error_match_message() {
         let result = get_result(
             r#"x # error: "contains this""#,
-            vec![ExpectedDiagnostic::new(
-                "anything",
-                "message contains this",
-                0,
-            )],
+            vec![TestDiagnostic::new("anything", "message contains this", 0)],
         );
 
         assert_ok(&result);
@@ -636,7 +604,7 @@ mod tests {
     fn error_wrong_message() {
         let result = get_result(
             r#"x # error: "contains this""#,
-            vec![ExpectedDiagnostic::new("anything", "Any message", 0)],
+            vec![TestDiagnostic::new("anything", "Any message", 0)],
         );
 
         assert_fail(
@@ -655,7 +623,7 @@ mod tests {
     fn error_match_column_and_rule() {
         let result = get_result(
             "x # error: 1 [some-rule]",
-            vec![ExpectedDiagnostic::new("some-rule", "Any message", 0)],
+            vec![TestDiagnostic::new("some-rule", "Any message", 0)],
         );
 
         assert_ok(&result);
@@ -665,7 +633,7 @@ mod tests {
     fn error_wrong_column() {
         let result = get_result(
             "x # error: 2 [rule]",
-            vec![ExpectedDiagnostic::new("rule", "Any message", 0)],
+            vec![TestDiagnostic::new("rule", "Any message", 0)],
         );
 
         assert_fail(
@@ -684,11 +652,7 @@ mod tests {
     fn error_match_column_and_message() {
         let result = get_result(
             r#"x # error: 1 "contains this""#,
-            vec![ExpectedDiagnostic::new(
-                "anything",
-                "message contains this",
-                0,
-            )],
+            vec![TestDiagnostic::new("anything", "message contains this", 0)],
         );
 
         assert_ok(&result);
@@ -698,11 +662,7 @@ mod tests {
     fn error_match_rule_and_message() {
         let result = get_result(
             r#"x # error: [a-rule] "contains this""#,
-            vec![ExpectedDiagnostic::new(
-                "a-rule",
-                "message contains this",
-                0,
-            )],
+            vec![TestDiagnostic::new("a-rule", "message contains this", 0)],
         );
 
         assert_ok(&result);
@@ -712,11 +672,7 @@ mod tests {
     fn error_match_all() {
         let result = get_result(
             r#"x # error: 1 [a-rule] "contains this""#,
-            vec![ExpectedDiagnostic::new(
-                "a-rule",
-                "message contains this",
-                0,
-            )],
+            vec![TestDiagnostic::new("a-rule", "message contains this", 0)],
         );
 
         assert_ok(&result);
@@ -726,11 +682,7 @@ mod tests {
     fn error_match_all_wrong_column() {
         let result = get_result(
             r#"x # error: 2 [some-rule] "contains this""#,
-            vec![ExpectedDiagnostic::new(
-                "some-rule",
-                "message contains this",
-                0,
-            )],
+            vec![TestDiagnostic::new("some-rule", "message contains this", 0)],
         );
 
         assert_fail(
@@ -749,7 +701,7 @@ mod tests {
     fn error_match_all_wrong_rule() {
         let result = get_result(
             r#"x # error: 1 [some-rule] "contains this""#,
-            vec![ExpectedDiagnostic::new(
+            vec![TestDiagnostic::new(
                 "other-rule",
                 "message contains this",
                 0,
@@ -772,7 +724,7 @@ mod tests {
     fn error_match_all_wrong_message() {
         let result = get_result(
             r#"x # error: 1 [some-rule] "contains this""#,
-            vec![ExpectedDiagnostic::new("some-rule", "Any message", 0)],
+            vec![TestDiagnostic::new("some-rule", "Any message", 0)],
         );
 
         assert_fail(
@@ -805,9 +757,9 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("line-two", "msg", two),
-                ExpectedDiagnostic::new("line-three", "msg", three),
-                ExpectedDiagnostic::new("line-five", "msg", five),
+                TestDiagnostic::new("line-two", "msg", two),
+                TestDiagnostic::new("line-three", "msg", three),
+                TestDiagnostic::new("line-five", "msg", five),
             ],
         );
 
@@ -836,8 +788,8 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("line-one", "msg", one),
-                ExpectedDiagnostic::new("line-two", "msg", two),
+                TestDiagnostic::new("line-one", "msg", one),
+                TestDiagnostic::new("line-two", "msg", two),
             ],
         );
 
@@ -857,8 +809,8 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("one-rule", "msg", x),
-                ExpectedDiagnostic::new("other-rule", "msg", x),
+                TestDiagnostic::new("one-rule", "msg", x),
+                TestDiagnostic::new("other-rule", "msg", x),
             ],
         );
 
@@ -878,8 +830,8 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("one-rule", "msg", x),
-                ExpectedDiagnostic::new("one-rule", "msg", x),
+                TestDiagnostic::new("one-rule", "msg", x),
+                TestDiagnostic::new("one-rule", "msg", x),
             ],
         );
 
@@ -899,9 +851,9 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("one-rule", "msg", x),
-                ExpectedDiagnostic::new("other-rule", "msg", x),
-                ExpectedDiagnostic::new("third-rule", "msg", x),
+                TestDiagnostic::new("one-rule", "msg", x),
+                TestDiagnostic::new("other-rule", "msg", x),
+                TestDiagnostic::new("third-rule", "msg", x),
             ],
         );
 
@@ -925,8 +877,8 @@ mod tests {
         let result = get_result(
             &source,
             vec![
-                ExpectedDiagnostic::new("undefined-reveal", "msg", reveal),
-                ExpectedDiagnostic::new("revealed-type", "Revealed type is `Literal[5]`", reveal),
+                TestDiagnostic::new("undefined-reveal", "msg", reveal),
+                TestDiagnostic::new("revealed-type", "Revealed type is `Literal[5]`", reveal),
             ],
         );
 
@@ -939,7 +891,7 @@ mod tests {
         let x = source.find('x').unwrap();
         let result = get_result(
             source,
-            vec![ExpectedDiagnostic::new("some-rule", "some message", x)],
+            vec![TestDiagnostic::new("some-rule", "some message", x)],
         );
 
         assert_fail(
@@ -960,7 +912,7 @@ mod tests {
         let x = source.find('x').unwrap();
         let result = get_result(
             source,
-            vec![ExpectedDiagnostic::new("some-rule", "some message", x)],
+            vec![TestDiagnostic::new("some-rule", "some message", x)],
         );
 
         assert_fail(

crates/red_knot_vendored/vendor/typeshed/source_commit.txt

@@ -1 +1 @@
-5052fa2f18db4493892e0f2775030683c9d06531
+d262beb07502cda412db2179fb406d45d1a9486f

crates/red_knot_vendored/vendor/typeshed/stdlib/VERSIONS

@@ -24,22 +24,18 @@ _asyncio: 3.0-
 _bisect: 3.0-
 _blake2: 3.6-
 _bootlocale: 3.4-3.9
-_bz2: 3.3-
 _codecs: 3.0-
 _collections_abc: 3.3-
 _compat_pickle: 3.1-
 _compression: 3.5-
-_contextvars: 3.7-
 _csv: 3.0-
 _ctypes: 3.0-
 _curses: 3.0-
-_dbm: 3.0-
 _decimal: 3.3-
 _dummy_thread: 3.0-3.8
 _dummy_threading: 3.0-3.8
 _frozen_importlib: 3.0-
 _frozen_importlib_external: 3.5-
-_gdbm: 3.0-
 _heapq: 3.0-
 _imp: 3.0-
 _interpchannels: 3.13-
@@ -49,7 +45,6 @@ _io: 3.0-
 _json: 3.0-
 _locale: 3.0-
 _lsprof: 3.0-
-_lzma: 3.3-
 _markupbase: 3.0-
 _msi: 3.0-3.12
 _operator: 3.4-
@@ -57,14 +52,12 @@ _osx_support: 3.0-
 _posixsubprocess: 3.2-
 _py_abc: 3.7-
 _pydecimal: 3.5-
-_queue: 3.7-
 _random: 3.0-
 _sitebuiltins: 3.4-
 _socket: 3.0-  # present in 3.0 at runtime, but not in typeshed
 _sqlite3: 3.0-
 _ssl: 3.0-
 _stat: 3.4-
-_struct: 3.0-
 _thread: 3.0-
 _threading_local: 3.0-
 _tkinter: 3.0-

crates/red_knot_vendored/vendor/typeshed/stdlib/_bz2.pyi

@@ -1,18 +0,0 @@
-from _typeshed import ReadableBuffer
-from typing import final
-
-@final
-class BZ2Compressor:
-    def __init__(self, compresslevel: int = 9) -> None: ...
-    def compress(self, data: ReadableBuffer, /) -> bytes: ...
-    def flush(self) -> bytes: ...
-
-@final
-class BZ2Decompressor:
-    def decompress(self, data: ReadableBuffer, max_length: int = -1) -> bytes: ...
-    @property
-    def eof(self) -> bool: ...
-    @property
-    def needs_input(self) -> bool: ...
-    @property
-    def unused_data(self) -> bytes: ...

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

@@ -1,61 +0,0 @@
-import sys
-from collections.abc import Callable, Iterator, Mapping
-from typing import Any, ClassVar, Generic, TypeVar, final, overload
-from typing_extensions import ParamSpec
-
-if sys.version_info >= (3, 9):
-    from types import GenericAlias
-
-_T = TypeVar("_T")
-_D = TypeVar("_D")
-_P = ParamSpec("_P")
-
-@final
-class ContextVar(Generic[_T]):
-    @overload
-    def __init__(self, name: str) -> None: ...
-    @overload
-    def __init__(self, name: str, *, default: _T) -> None: ...
-    def __hash__(self) -> int: ...
-    @property
-    def name(self) -> str: ...
-    @overload
-    def get(self) -> _T: ...
-    @overload
-    def get(self, default: _T, /) -> _T: ...
-    @overload
-    def get(self, default: _D, /) -> _D | _T: ...
-    def set(self, value: _T, /) -> Token[_T]: ...
-    def reset(self, token: Token[_T], /) -> None: ...
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
-
-@final
-class Token(Generic[_T]):
-    @property
-    def var(self) -> ContextVar[_T]: ...
-    @property
-    def old_value(self) -> Any: ...  # returns either _T or MISSING, but that's hard to express
-    MISSING: ClassVar[object]
-    if sys.version_info >= (3, 9):
-        def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
-
-def copy_context() -> Context: ...
-
-# It doesn't make sense to make this generic, because for most Contexts each ContextVar will have
-# a different value.
-@final
-class Context(Mapping[ContextVar[Any], Any]):
-    def __init__(self) -> None: ...
-    @overload
-    def get(self, key: ContextVar[_T], default: None = None, /) -> _T | None: ...
-    @overload
-    def get(self, key: ContextVar[_T], default: _T, /) -> _T: ...
-    @overload
-    def get(self, key: ContextVar[_T], default: _D, /) -> _T | _D: ...
-    def run(self, callable: Callable[_P, _T], *args: _P.args, **kwargs: _P.kwargs) -> _T: ...
-    def copy(self) -> Context: ...
-    def __getitem__(self, key: ContextVar[_T], /) -> _T: ...
-    def __iter__(self) -> Iterator[ContextVar[Any]]: ...
-    def __len__(self) -> int: ...
-    def __eq__(self, value: object, /) -> bool: ...

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

@@ -1,43 +0,0 @@
-import sys
-from _typeshed import ReadOnlyBuffer, StrOrBytesPath
-from types import TracebackType
-from typing import TypeVar, overload
-from typing_extensions import Self, TypeAlias
-
-if sys.platform != "win32":
-    _T = TypeVar("_T")
-    _KeyType: TypeAlias = str | ReadOnlyBuffer
-    _ValueType: TypeAlias = str | ReadOnlyBuffer
-
-    class error(OSError): ...
-    library: str
-
-    # Actual typename dbm, not exposed by the implementation
-    class _dbm:
-        def close(self) -> None: ...
-        if sys.version_info >= (3, 13):
-            def clear(self) -> None: ...
-
-        def __getitem__(self, item: _KeyType) -> bytes: ...
-        def __setitem__(self, key: _KeyType, value: _ValueType) -> None: ...
-        def __delitem__(self, key: _KeyType) -> None: ...
-        def __len__(self) -> int: ...
-        def __del__(self) -> None: ...
-        def __enter__(self) -> Self: ...
-        def __exit__(
-            self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: TracebackType | None
-        ) -> None: ...
-        @overload
-        def get(self, k: _KeyType) -> bytes | None: ...
-        @overload
-        def get(self, k: _KeyType, default: _T) -> bytes | _T: ...
-        def keys(self) -> list[bytes]: ...
-        def setdefault(self, k: _KeyType, default: _ValueType = ...) -> bytes: ...
-        # Don't exist at runtime
-        __new__: None  # type: ignore[assignment]
-        __init__: None  # type: ignore[assignment]
-
-    if sys.version_info >= (3, 11):
-        def open(filename: StrOrBytesPath, flags: str = "r", mode: int = 0o666, /) -> _dbm: ...
-    else:
-        def open(filename: str, flags: str = "r", mode: int = 0o666, /) -> _dbm: ...