Add rule registry and rule selection

.github/workflows/build-binaries.yml

@@ -53,9 +53,9 @@ jobs:
           args: --out dist
       - name: "Test sdist"
         run: |
-          pip install dist/${PACKAGE_NAME}-*.tar.gz --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          pip install dist/${{ env.PACKAGE_NAME }}-*.tar.gz --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
       - name: "Upload sdist"
         uses: actions/upload-artifact@v4
         with:
@@ -125,7 +125,7 @@ jobs:
           args: --release --locked --out dist
       - name: "Test wheel - aarch64"
         run: |
-          pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
           ruff --help
           python -m ruff --help
       - name: "Upload wheels"
@@ -186,9 +186,9 @@ jobs:
         if: ${{ !startsWith(matrix.platform.target, 'aarch64') }}
         shell: bash
         run: |
-          python -m pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          python -m pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:
@@ -236,9 +236,9 @@ jobs:
       - name: "Test wheel"
         if: ${{ startsWith(matrix.target, 'x86_64') }}
         run: |
-          pip install dist/${PACKAGE_NAME}-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ${{ env.MODULE_NAME }} --help
+          python -m ${{ env.MODULE_NAME }} --help
       - name: "Upload wheels"
         uses: actions/upload-artifact@v4
         with:

.github/workflows/build-docker.yml

@@ -72,7 +72,7 @@ jobs:
       - name: Normalize Platform Pair (replace / with -)
         run: |
           platform=${{ matrix.platform }}
-          echo "PLATFORM_TUPLE=${platform//\//-}" >> "$GITHUB_ENV"
+          echo "PLATFORM_TUPLE=${platform//\//-}" >> $GITHUB_ENV
 
       # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
       - name: Build and push by digest
@@ -87,10 +87,9 @@ jobs:
           outputs: type=image,name=${{ env.RUFF_BASE_IMG }},push-by-digest=true,name-canonical=true,push=${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
 
       - name: Export digests
-        env:
-          digest: ${{ steps.build.outputs.digest }}
         run: |
           mkdir -p /tmp/digests
+          digest="${{ steps.build.outputs.digest }}"
           touch "/tmp/digests/${digest#sha256:}"
 
       - name: Upload digests
@@ -144,7 +143,7 @@ jobs:
         run: |
           docker buildx imagetools create \
             $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)
+            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)
 
   docker-publish-extra:
     name: Publish additional Docker image based on ${{ matrix.image-mapping }}
@@ -183,7 +182,7 @@ jobs:
           # Generate Dockerfile content
           cat <<EOF > Dockerfile
           FROM ${BASE_IMAGE}
-          COPY --from=${RUFF_BASE_IMG}:latest /ruff /usr/local/bin/ruff
+          COPY --from=${{ env.RUFF_BASE_IMG }}:latest /ruff /usr/local/bin/ruff
           ENTRYPOINT []
           CMD ["/usr/local/bin/ruff"]
           EOF
@@ -203,14 +202,14 @@ jobs:
           TAG_PATTERNS="${TAG_PATTERNS%\\n}"
 
           # Export image cache name
-          echo "IMAGE_REF=${BASE_IMAGE//:/-}" >> "$GITHUB_ENV"
+          echo "IMAGE_REF=${BASE_IMAGE//:/-}" >> $GITHUB_ENV
 
           # Export tag patterns using the multiline env var syntax
           {
             echo "TAG_PATTERNS<<EOF"
             echo -e "${TAG_PATTERNS}"
             echo EOF
-          } >> "$GITHUB_ENV"
+          } >> $GITHUB_ENV
 
       - name: Extract metadata (tags, labels) for Docker
         id: meta
@@ -289,4 +288,4 @@ jobs:
           docker buildx imagetools create \
             "${annotations[@]}" \
             $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)
+            $(printf '${{ env.RUFF_BASE_IMG }}@sha256:%s ' *)

.github/workflows/ci.yaml

@@ -312,7 +312,7 @@ jobs:
     name: "cargo fuzz build"
     runs-on: ubuntu-latest
     needs: determine_changes
-    if: ${{ github.ref == 'refs/heads/main' || needs.determine_changes.outputs.fuzz == 'true' || needs.determine_changes.outputs.code == 'true' }}
+    if: ${{ github.ref == 'refs/heads/main' || needs.determine_changes.outputs.fuzz == 'true' }}
     timeout-minutes: 10
     steps:
       - uses: actions/checkout@v4

.github/workflows/publish-docs.yml

@@ -49,11 +49,13 @@ jobs:
 
       - name: "Set branch name"
         run: |
+          version="${{ env.version }}"
+          display_name="${{ env.display_name }}"
           timestamp="$(date +%s)"
 
           # create branch_display_name from display_name by replacing all
           # characters disallowed in git branch names with hyphens
-          branch_display_name="$(echo "${display_name}" | tr -c '[:alnum:]._' '-' | tr -s '-')"
+          branch_display_name="$(echo "$display_name" | tr -c '[:alnum:]._' '-' | tr -s '-')"
 
           echo "branch_name=update-docs-$branch_display_name-$timestamp" >> $GITHUB_ENV
           echo "timestamp=$timestamp" >> $GITHUB_ENV
@@ -91,7 +93,9 @@ jobs:
         run: mkdocs build --strict -f mkdocs.public.yml
 
       - name: "Clone docs repo"
-        run: git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
+        run: |
+          version="${{ env.version }}"
+          git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
 
       - name: "Copy docs"
         run: rm -rf astral-docs/site/ruff && mkdir -p astral-docs/site && cp -r site/ruff astral-docs/site/
@@ -99,10 +103,12 @@ jobs:
       - name: "Commit docs"
         working-directory: astral-docs
         run: |
+          branch_name="${{ env.branch_name }}"
+
           git config user.name "astral-docs-bot"
           git config user.email "176161322+astral-docs-bot@users.noreply.github.com"
 
-          git checkout -b "${branch_name}"
+          git checkout -b $branch_name
           git add site/ruff
           git commit -m "Update ruff documentation for $version"
 
@@ -111,8 +117,12 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
         run: |
+          version="${{ env.version }}"
+          display_name="${{ env.display_name }}"
+          branch_name="${{ env.branch_name }}"
+
           # set the PR title
-          pull_request_title="Update ruff documentation for "${display_name}""
+          pull_request_title="Update ruff documentation for $display_name"
 
           # Delete any existing pull requests that are open for this version
           # by checking against pull_request_title because the new PR will
@@ -121,12 +131,12 @@ jobs:
             xargs -I {} gh pr close {}
 
           # push the branch to GitHub
-          git push origin "${branch_name}"
+          git push origin $branch_name
 
           # create the PR
-          gh pr create --base main --head "${branch_name}" \
+          gh pr create --base main --head $branch_name \
             --title "$pull_request_title" \
-            --body "Automated documentation update for "${display_name}"" \
+            --body "Automated documentation update for $display_name" \
             --label "documentation"
 
       - name: "Merge Pull Request"
@@ -135,7 +145,9 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
         run: |
+          branch_name="${{ env.branch_name }}"
+
           # auto-merge the PR if the build was triggered by a release. Manual builds should be reviewed by a human.
           # give the PR a few seconds to be created before trying to auto-merge it
           sleep 10
-          gh pr merge --squash "${branch_name}"
+          gh pr merge --squash $branch_name

.github/workflows/sync_typeshed.yaml

@@ -31,7 +31,7 @@ jobs:
         with:
           repository: python/typeshed
           path: typeshed
-          persist-credentials: false
+          persist-credentials: true
       - name: Setup git
         run: |
           git config --global user.name typeshedbot

.pre-commit-config.yaml

@@ -95,6 +95,8 @@ repos:
         # `release.yml` is autogenerated by `dist`; security issues need to be fixed there
         # (https://opensource.axo.dev/cargo-dist/)
         exclude: .github/workflows/release.yml
+        # We could consider enabling the low-severity warnings, but they're noisy
+        args: [--min-severity=medium]
 
   - repo: https://github.com/python-jsonschema/check-jsonschema
     rev: 0.30.0

CHANGELOG.md

@@ -1,40 +1,5 @@
 # Changelog
 
-## 0.8.3
-
-### Preview features
-
-- Fix fstring formatting removing overlong implicit concatenated string in expression part ([#14811](https://github.com/astral-sh/ruff/pull/14811))
-- \[`airflow`\] Add fix to remove deprecated keyword arguments (`AIR302`) ([#14887](https://github.com/astral-sh/ruff/pull/14887))
-- \[`airflow`\]: Extend rule to include deprecated names for Airflow 3.0 (`AIR302`) ([#14765](https://github.com/astral-sh/ruff/pull/14765) and [#14804](https://github.com/astral-sh/ruff/pull/14804))
-- \[`flake8-bugbear`\] Improve error messages for `except*` (`B025`, `B029`, `B030`, `B904`) ([#14815](https://github.com/astral-sh/ruff/pull/14815))
-- \[`flake8-bugbear`\] `itertools.batched()` without explicit `strict` (`B911`) ([#14408](https://github.com/astral-sh/ruff/pull/14408))
-- \[`flake8-use-pathlib`\] Dotless suffix passed to `Path.with_suffix()` (`PTH210`) ([#14779](https://github.com/astral-sh/ruff/pull/14779))
-- \[`pylint`\] Include parentheses and multiple comparators in check for `boolean-chained-comparison` (`PLR1716`) ([#14781](https://github.com/astral-sh/ruff/pull/14781))
-- \[`ruff`\] Do not simplify `round()` calls (`RUF046`) ([#14832](https://github.com/astral-sh/ruff/pull/14832))
-- \[`ruff`\] Don't emit `used-dummy-variable` on function parameters (`RUF052`) ([#14818](https://github.com/astral-sh/ruff/pull/14818))
-- \[`ruff`\] Implement `if-key-in-dict-del` (`RUF051`) ([#14553](https://github.com/astral-sh/ruff/pull/14553))
-- \[`ruff`\] Mark autofix for `RUF052` as always unsafe ([#14824](https://github.com/astral-sh/ruff/pull/14824))
-- \[`ruff`\] Teach autofix for `used-dummy-variable` about TypeVars etc. (`RUF052`) ([#14819](https://github.com/astral-sh/ruff/pull/14819))
-
-### Rule changes
-
-- \[`flake8-bugbear`\] Offer unsafe autofix for `no-explicit-stacklevel` (`B028`) ([#14829](https://github.com/astral-sh/ruff/pull/14829))
-- \[`flake8-pyi`\] Skip all type definitions in `string-or-bytes-too-long` (`PYI053`) ([#14797](https://github.com/astral-sh/ruff/pull/14797))
-- \[`pyupgrade`\] Do not report when a UTF-8 comment is followed by a non-UTF-8 one (`UP009`) ([#14728](https://github.com/astral-sh/ruff/pull/14728))
-- \[`pyupgrade`\] Mark fixes for `convert-typed-dict-functional-to-class` and `convert-named-tuple-functional-to-class` as unsafe if they will remove comments (`UP013`, `UP014`) ([#14842](https://github.com/astral-sh/ruff/pull/14842))
-
-### Bug fixes
-
-- Raise syntax error for mixing `except` and `except*` ([#14895](https://github.com/astral-sh/ruff/pull/14895))
-- \[`flake8-bugbear`\] Fix `B028` to allow `stacklevel` to be explicitly assigned as a positional argument ([#14868](https://github.com/astral-sh/ruff/pull/14868))
-- \[`flake8-bugbear`\] Skip `B028` if `warnings.warn` is called with `*args` or `**kwargs` ([#14870](https://github.com/astral-sh/ruff/pull/14870))
-- \[`flake8-comprehensions`\] Skip iterables with named expressions in `unnecessary-map` (`C417`) ([#14827](https://github.com/astral-sh/ruff/pull/14827))
-- \[`flake8-pyi`\] Also remove `self` and `cls`'s annotation (`PYI034`) ([#14801](https://github.com/astral-sh/ruff/pull/14801))
-- \[`flake8-pytest-style`\] Fix `pytest-parametrize-names-wrong-type` (`PT006`) to edit both `argnames` and `argvalues` if both of them are single-element tuples/lists ([#14699](https://github.com/astral-sh/ruff/pull/14699))
-- \[`perflint`\] Improve autofix for `PERF401` ([#14369](https://github.com/astral-sh/ruff/pull/14369))
-- \[`pylint`\] Fix `PLW1508` false positive for default string created via a mult operation ([#14841](https://github.com/astral-sh/ruff/pull/14841))
-
 ## 0.8.2
 
 ### Preview features

Cargo.lock

@@ -2517,7 +2517,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.8.3"
+version = "0.8.2"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2736,7 +2736,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.8.3"
+version = "0.8.2"
 dependencies = [
  "aho-corasick",
  "annotate-snippets 0.9.2",
@@ -3051,7 +3051,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.8.3"
+version = "0.8.2"
 dependencies = [
  "console_error_panic_hook",
  "console_log",

README.md

@@ -140,8 +140,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
 
 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.8.3/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.8.3/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.8.2/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.8.2/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -174,7 +174,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.8.3
+  rev: v0.8.2
   hooks:
     # Run the linter.
     - id: ruff

crates/red_knot/src/main.rs

@@ -5,7 +5,6 @@ use anyhow::{anyhow, Context};
 use clap::Parser;
 use colored::Colorize;
 use crossbeam::channel as crossbeam_channel;
-use python_version::PythonVersion;
 use red_knot_python_semantic::SitePackages;
 use red_knot_server::run_server;
 use red_knot_workspace::db::RootDatabase;
@@ -16,11 +15,12 @@ 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};
 
 mod logging;
-mod python_version;
+mod target_version;
 mod verbosity;
 
 #[derive(Debug, Parser)]
@@ -34,39 +34,54 @@ struct Args {
     #[command(subcommand)]
     pub(crate) command: Option<Command>,
 
-    /// Run the command within the given project directory.
-    ///
-    /// All `pyproject.toml` files will be discovered by walking up the directory tree from the given project directory,
-    /// as will the project's virtual environment (`.venv`) unless the `venv-path` option is set.
-    ///
-    /// Other command-line arguments (such as relative paths) will be resolved relative to the current working directory.
-    #[arg(long, value_name = "PROJECT")]
-    project: Option<SystemPathBuf>,
+    #[arg(
+        long,
+        help = "Changes the current working directory.",
+        long_help = "Changes the current working directory before any specified operations. This affects the workspace and configuration discovery.",
+        value_name = "PATH"
+    )]
+    current_directory: Option<SystemPathBuf>,
 
-    /// Path to the virtual environment the project uses.
-    ///
-    /// If provided, red-knot will use the `site-packages` directory of this virtual environment
-    /// to resolve type information for the project's third-party dependencies.
-    #[arg(long, value_name = "PATH")]
+    #[arg(
+        long,
+        help = "Path to the virtual environment the project uses",
+        long_help = "\
+Path to the virtual environment the project uses. \
+If provided, red-knot will use the `site-packages` directory of this virtual environment \
+to resolve type information for the project's third-party dependencies.",
+        value_name = "PATH"
+    )]
     venv_path: Option<SystemPathBuf>,
 
-    /// Custom directory to use for stdlib typeshed stubs.
-    #[arg(long, value_name = "PATH", alias = "custom-typeshed-dir")]
-    typeshed: Option<SystemPathBuf>,
+    #[arg(
+        long,
+        value_name = "DIRECTORY",
+        help = "Custom directory to use for stdlib typeshed stubs"
+    )]
+    custom_typeshed_dir: Option<SystemPathBuf>,
 
-    /// Additional path to use as a module-resolution source (can be passed multiple times).
-    #[arg(long, value_name = "PATH")]
+    #[arg(
+        long,
+        value_name = "PATH",
+        help = "Additional path to use as a module-resolution source (can be passed multiple times)"
+    )]
     extra_search_path: Option<Vec<SystemPathBuf>>,
 
-    /// Python version to assume when resolving types.
-    #[arg(long, value_name = "VERSION", alias = "target-version")]
-    python_version: Option<PythonVersion>,
+    #[arg(
+        long,
+        help = "Python version to assume when resolving types",
+        value_name = "VERSION"
+    )]
+    target_version: Option<TargetVersion>,
 
     #[clap(flatten)]
     verbosity: Verbosity,
 
-    /// Run in watch mode by re-running whenever files change.
-    #[arg(long, short = 'W')]
+    #[arg(
+        long,
+        help = "Run in watch mode by re-running whenever files change",
+        short = 'W'
+    )]
     watch: bool,
 }
 
@@ -74,8 +89,8 @@ impl Args {
     fn to_configuration(&self, cli_cwd: &SystemPath) -> Configuration {
         let mut configuration = Configuration::default();
 
-        if let Some(python_version) = self.python_version {
-            configuration.python_version = Some(python_version.into());
+        if let Some(target_version) = self.target_version {
+            configuration.target_version = Some(target_version.into());
         }
 
         if let Some(venv_path) = &self.venv_path {
@@ -84,8 +99,9 @@ impl Args {
             });
         }
 
-        if let Some(typeshed) = &self.typeshed {
-            configuration.search_paths.typeshed = Some(SystemPath::absolute(typeshed, cli_cwd));
+        if let Some(custom_typeshed_dir) = &self.custom_typeshed_dir {
+            configuration.search_paths.custom_typeshed =
+                Some(SystemPath::absolute(custom_typeshed_dir, cli_cwd));
         }
 
         if let Some(extra_search_paths) = &self.extra_search_path {
@@ -151,13 +167,15 @@ fn run() -> anyhow::Result<ExitStatus> {
     };
 
     let cwd = args
-        .project
+        .current_directory
         .as_ref()
         .map(|cwd| {
             if cwd.as_std_path().is_dir() {
                 Ok(SystemPath::absolute(cwd, &cli_base_path))
             } else {
-                Err(anyhow!("Provided project path `{cwd}` is not a directory"))
+                Err(anyhow!(
+                    "Provided current-directory path `{cwd}` is not a directory"
+                ))
             }
         })
         .transpose()?

crates/red_knot/src/python_version.rs

@@ -1,68 +0,0 @@
-/// Enumeration of all supported Python versions
-///
-/// TODO: unify with the `PythonVersion` enum in the linter/formatter crates?
-#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
-pub enum PythonVersion {
-    #[value(name = "3.7")]
-    Py37,
-    #[value(name = "3.8")]
-    Py38,
-    #[default]
-    #[value(name = "3.9")]
-    Py39,
-    #[value(name = "3.10")]
-    Py310,
-    #[value(name = "3.11")]
-    Py311,
-    #[value(name = "3.12")]
-    Py312,
-    #[value(name = "3.13")]
-    Py313,
-}
-
-impl PythonVersion {
-    const fn as_str(self) -> &'static str {
-        match self {
-            Self::Py37 => "3.7",
-            Self::Py38 => "3.8",
-            Self::Py39 => "3.9",
-            Self::Py310 => "3.10",
-            Self::Py311 => "3.11",
-            Self::Py312 => "3.12",
-            Self::Py313 => "3.13",
-        }
-    }
-}
-
-impl std::fmt::Display for PythonVersion {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.write_str(self.as_str())
-    }
-}
-
-impl From<PythonVersion> for red_knot_python_semantic::PythonVersion {
-    fn from(value: PythonVersion) -> Self {
-        match value {
-            PythonVersion::Py37 => Self::PY37,
-            PythonVersion::Py38 => Self::PY38,
-            PythonVersion::Py39 => Self::PY39,
-            PythonVersion::Py310 => Self::PY310,
-            PythonVersion::Py311 => Self::PY311,
-            PythonVersion::Py312 => Self::PY312,
-            PythonVersion::Py313 => Self::PY313,
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::python_version::PythonVersion;
-
-    #[test]
-    fn same_default_as_python_version() {
-        assert_eq!(
-            red_knot_python_semantic::PythonVersion::from(PythonVersion::default()),
-            red_knot_python_semantic::PythonVersion::default()
-        );
-    }
-}

crates/red_knot/src/target_version.rs

@@ -0,0 +1,62 @@
+/// Enumeration of all supported Python versions
+///
+/// TODO: unify with the `PythonVersion` enum in the linter/formatter crates?
+#[derive(Copy, Clone, Hash, Debug, PartialEq, Eq, PartialOrd, Ord, Default, clap::ValueEnum)]
+pub enum TargetVersion {
+    Py37,
+    Py38,
+    #[default]
+    Py39,
+    Py310,
+    Py311,
+    Py312,
+    Py313,
+}
+
+impl TargetVersion {
+    const fn as_str(self) -> &'static str {
+        match self {
+            Self::Py37 => "py37",
+            Self::Py38 => "py38",
+            Self::Py39 => "py39",
+            Self::Py310 => "py310",
+            Self::Py311 => "py311",
+            Self::Py312 => "py312",
+            Self::Py313 => "py313",
+        }
+    }
+}
+
+impl std::fmt::Display for TargetVersion {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl From<TargetVersion> for red_knot_python_semantic::PythonVersion {
+    fn from(value: TargetVersion) -> Self {
+        match value {
+            TargetVersion::Py37 => Self::PY37,
+            TargetVersion::Py38 => Self::PY38,
+            TargetVersion::Py39 => Self::PY39,
+            TargetVersion::Py310 => Self::PY310,
+            TargetVersion::Py311 => Self::PY311,
+            TargetVersion::Py312 => Self::PY312,
+            TargetVersion::Py313 => Self::PY313,
+        }
+    }
+}
+
+#[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

@@ -282,7 +282,7 @@ where
         .extra_paths
         .iter()
         .flatten()
-        .chain(search_paths.typeshed.iter())
+        .chain(search_paths.custom_typeshed.iter())
         .chain(search_paths.site_packages.iter().flat_map(|site_packages| {
             if let SitePackages::Known(path) = site_packages {
                 path.as_slice()
@@ -296,7 +296,7 @@ where
     }
 
     let configuration = Configuration {
-        python_version: Some(PythonVersion::PY312),
+        target_version: Some(PythonVersion::PY312),
         search_paths,
     };
 
@@ -888,7 +888,7 @@ fn changed_versions_file() -> anyhow::Result<()> {
             Ok(())
         },
         |root_path, _workspace_path| SearchPathConfiguration {
-            typeshed: Some(root_path.join("typeshed")),
+            custom_typeshed: Some(root_path.join("typeshed")),
             ..SearchPathConfiguration::default()
         },
     )?;

crates/red_knot_python_semantic/Cargo.toml

@@ -53,9 +53,5 @@ tempfile = { workspace = true }
 quickcheck = { version = "1.0.3", default-features = false }
 quickcheck_macros = { version = "1.0.0" }
 
-[features]
-serde = ["ruff_db/serde", "dep:serde"]
-
 [lints]
 workspace = true
-

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

@@ -1,94 +0,0 @@
-# `Annotated`
-
-`Annotated` attaches arbitrary metadata to a given type.
-
-## Usages
-
-`Annotated[T, ...]` is equivalent to `T`: All metadata arguments are simply ignored.
-
-```py
-from typing_extensions import Annotated
-
-def _(x: Annotated[int, "foo"]):
-    reveal_type(x)  # revealed: int
-
-def _(x: Annotated[int, lambda: 0 + 1 * 2 // 3, _(4)]):
-    reveal_type(x)  # revealed: int
-
-def _(x: Annotated[int, "arbitrary", "metadata", "elements", "are", "fine"]):
-    reveal_type(x)  # revealed: int
-
-def _(x: Annotated[tuple[str, int], bytes]):
-    reveal_type(x)  # revealed: tuple[str, int]
-```
-
-## Parameterization
-
-It is invalid to parameterize `Annotated` with less than two arguments.
-
-```py
-from typing_extensions import Annotated
-
-# error: [invalid-type-form] "`Annotated` requires at least two arguments when used in an annotation or type expression"
-def _(x: Annotated):
-    reveal_type(x)  # revealed: Unknown
-
-def _(flag: bool):
-    if flag:
-        X = Annotated
-    else:
-        X = bool
-
-    # error: [invalid-type-form] "`Annotated` requires at least two arguments when used in an annotation or type expression"
-    def f(y: X):
-        reveal_type(y)  # revealed: Unknown | bool
-
-# error: [invalid-type-form] "`Annotated` requires at least two arguments when used in an annotation or type expression"
-def _(x: Annotated | bool):
-    reveal_type(x)  # revealed: Unknown | bool
-
-# error: [invalid-type-form]
-def _(x: Annotated[()]):
-    reveal_type(x)  # revealed: Unknown
-
-# error: [invalid-type-form]
-def _(x: Annotated[int]):
-    # `Annotated[T]` is invalid and will raise an error at runtime,
-    # but we treat it the same as `T` to provide better diagnostics later on.
-    # The subscription itself is still reported, regardless.
-    # Same for the `(int,)` form below.
-    reveal_type(x)  # revealed: int
-
-# error: [invalid-type-form]
-def _(x: Annotated[(int,)]):
-    reveal_type(x)  # revealed: int
-```
-
-## Inheritance
-
-### Correctly parameterized
-
-Inheriting from `Annotated[T, ...]` is equivalent to inheriting from `T` itself.
-
-```py
-from typing_extensions import Annotated
-
-# TODO: False positive
-# error: [invalid-base]
-class C(Annotated[int, "foo"]): ...
-
-# TODO: Should be `tuple[Literal[C], Literal[int], Literal[object]]`
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Unknown, Literal[object]]
-```
-
-### Not parameterized
-
-```py
-from typing_extensions import Annotated
-
-# At runtime, this is an error.
-# error: [invalid-base]
-class C(Annotated): ...
-
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Unknown, Literal[object]]
-```

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

@@ -34,7 +34,8 @@ If you define your own class named `Any`, using that in a type expression refers
 isn't a spelling of the Any type.
 
 ```py
-class Any: ...
+class Any:
+    pass
 
 x: Any
 
@@ -58,7 +59,8 @@ assignable to `int`.
 ```py
 from typing import Any
 
-class Subclass(Any): ...
+class Subclass(Any):
+    pass
 
 reveal_type(Subclass.__mro__)  # revealed: tuple[Literal[Subclass], Any, Literal[object]]
 
@@ -66,18 +68,8 @@ x: Subclass = 1  # error: [invalid-assignment]
 # TODO: no diagnostic
 y: int = Subclass()  # error: [invalid-assignment]
 
-def _(s: Subclass):
-    reveal_type(s)  # revealed: Subclass
-```
-
-## Invalid
-
-`Any` cannot be parameterized:
-
-```py
-from typing import Any
-
-# error: [invalid-type-form] "Type `typing.Any` expected no type parameter"
-def f(x: Any[int]):
-    reveal_type(x)  # revealed: Unknown
+def f() -> Subclass:
+    pass
+
+reveal_type(f())  # revealed: Subclass
 ```

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

@@ -27,19 +27,19 @@ def f():
 ```py
 from typing_extensions import Literal, LiteralString
 
-bad_union: Literal["hello", LiteralString]  # error: [invalid-type-form]
-bad_nesting: Literal[LiteralString]  # error: [invalid-type-form]
+bad_union: Literal["hello", LiteralString]  # error: [invalid-literal-parameter]
+bad_nesting: Literal[LiteralString]  # error: [invalid-literal-parameter]
 ```
 
-### Parameterized
+### Parametrized
 
-`LiteralString` cannot be parameterized.
+`LiteralString` cannot be parametrized.
 
 ```py
 from typing_extensions import LiteralString
 
-a: LiteralString[str]  # error: [invalid-type-form]
-b: LiteralString["foo"]  # error: [invalid-type-form]
+a: LiteralString[str]  # error: [invalid-type-parameter]
+b: LiteralString["foo"]  # error: [invalid-type-parameter]
 ```
 
 ### As a base class
@@ -89,26 +89,28 @@ vice versa.
 ```py
 from typing_extensions import Literal, LiteralString
 
-def _(flag: bool):
-    foo_1: Literal["foo"] = "foo"
-    bar_1: LiteralString = foo_1  # fine
+def coinflip() -> bool:
+    return True
 
-    foo_2 = "foo" if flag else "bar"
-    reveal_type(foo_2)  # revealed: Literal["foo", "bar"]
-    bar_2: LiteralString = foo_2  # fine
+foo_1: Literal["foo"] = "foo"
+bar_1: LiteralString = foo_1  # fine
 
-    foo_3: LiteralString = "foo" * 1_000_000_000
-    bar_3: str = foo_2  # fine
+foo_2 = "foo" if coinflip() else "bar"
+reveal_type(foo_2)  # revealed: Literal["foo", "bar"]
+bar_2: LiteralString = foo_2  # fine
 
-    baz_1: str = str()
-    qux_1: LiteralString = baz_1  # error: [invalid-assignment]
+foo_3: LiteralString = "foo" * 1_000_000_000
+bar_3: str = foo_2  # fine
 
-    baz_2: LiteralString = "baz" * 1_000_000_000
-    qux_2: Literal["qux"] = baz_2  # error: [invalid-assignment]
+baz_1: str = str()
+qux_1: LiteralString = baz_1  # error: [invalid-assignment]
 
-    baz_3 = "foo" if flag else 1
-    reveal_type(baz_3)  # revealed: Literal["foo"] | Literal[1]
-    qux_3: LiteralString = baz_3  # error: [invalid-assignment]
+baz_2: LiteralString = "baz" * 1_000_000_000
+qux_2: Literal["qux"] = baz_2  # error: [invalid-assignment]
+
+baz_3 = "foo" if coinflip() else 1
+reveal_type(baz_3)  # revealed: Literal["foo"] | Literal[1]
+qux_3: LiteralString = baz_3  # error: [invalid-assignment]
 ```
 
 ### Narrowing
@@ -135,7 +137,7 @@ if "" < lorem == "ipsum":
 
 ```toml
 [environment]
-python-version = "3.11"
+target-version = "3.11"
 ```
 
 ```py

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

@@ -21,7 +21,7 @@ reveal_type(stop())
 ```py
 from typing_extensions import NoReturn, Never, Any
 
-# error: [invalid-type-form] "Type `typing.Never` expected no type parameter"
+# error: [invalid-type-parameter] "Type `typing.Never` expected no type parameter"
 x: Never[int]
 a1: NoReturn
 a2: Never
@@ -51,7 +51,7 @@ def f():
 
 ```toml
 [environment]
-python-version = "3.11"
+target-version = "3.11"
 ```
 
 ```py

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

@@ -1,83 +0,0 @@
-# Typing-module aliases to other stdlib classes
-
-The `typing` module has various aliases to other stdlib classes. These are a legacy feature, but
-still need to be supported by a type checker.
-
-## Currently unsupported
-
-Support for most of these symbols is currently a TODO:
-
-```py
-import typing
-
-def f(
-    a: typing.List,
-    b: typing.List[int],
-    c: typing.Dict,
-    d: typing.Dict[int, str],
-    e: typing.DefaultDict,
-    f: typing.DefaultDict[str, int],
-    g: typing.Set,
-    h: typing.Set[int],
-    i: typing.FrozenSet,
-    j: typing.FrozenSet[str],
-    k: typing.OrderedDict,
-    l: typing.OrderedDict[int, str],
-    m: typing.Counter,
-    n: typing.Counter[int],
-):
-    reveal_type(a)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(b)  # revealed: @Todo(typing.List alias)
-    reveal_type(c)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(d)  # revealed: @Todo(typing.Dict alias)
-    reveal_type(e)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(f)  # revealed: @Todo(typing.DefaultDict[] alias)
-    reveal_type(g)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(h)  # revealed: @Todo(typing.Set alias)
-    reveal_type(i)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(j)  # revealed: @Todo(typing.FrozenSet alias)
-    reveal_type(k)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(l)  # revealed: @Todo(typing.OrderedDict alias)
-    reveal_type(m)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-    reveal_type(n)  # revealed: @Todo(typing.Counter[] alias)
-```
-
-## Inheritance
-
-The aliases can be inherited from. Some of these are still partially or wholly TODOs.
-
-```py
-import typing
-
-class A(typing.Dict): ...
-
-# TODO: should have `Generic`, should not have `Unknown`
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Literal[dict], Unknown, Literal[object]]
-
-class B(typing.List): ...
-
-# TODO: should have `Generic`, should not have `Unknown`
-reveal_type(B.__mro__)  # revealed: tuple[Literal[B], Literal[list], Unknown, Literal[object]]
-
-class C(typing.Set): ...
-
-# TODO: should have `Generic`, should not have `Unknown`
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[set], Unknown, Literal[object]]
-
-class D(typing.FrozenSet): ...
-
-# TODO: should have `Generic`, should not have `Unknown`
-reveal_type(D.__mro__)  # revealed: tuple[Literal[D], Literal[frozenset], Unknown, Literal[object]]
-
-class E(typing.DefaultDict): ...
-
-reveal_type(E.__mro__)  # revealed: tuple[Literal[E], @Todo(Support for more typing aliases as base classes), Literal[object]]
-
-class F(typing.OrderedDict): ...
-
-reveal_type(F.__mro__)  # revealed: tuple[Literal[F], @Todo(Support for more typing aliases as base classes), Literal[object]]
-
-class G(typing.Counter): ...
-
-reveal_type(G.__mro__)  # revealed: tuple[Literal[G], @Todo(Support for more typing aliases as base classes), Literal[object]]
-```

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

@@ -3,56 +3,75 @@
 ## Simple
 
 ```py
-def f(v: "int"):
-    reveal_type(v)  # revealed: int
+def f() -> "int":
+    return 1
+
+reveal_type(f())  # revealed: int
 ```
 
 ## Nested
 
 ```py
-def f(v: "'int'"):
-    reveal_type(v)  # revealed: int
+def f() -> "'int'":
+    return 1
+
+reveal_type(f())  # revealed: int
 ```
 
 ## Type expression
 
 ```py
-def f1(v: "int | str", w: "tuple[int, str]"):
-    reveal_type(v)  # revealed: int | str
-    reveal_type(w)  # revealed: tuple[int, str]
+def f1() -> "int | str":
+    return 1
+
+def f2() -> "tuple[int, str]":
+    return 1
+
+reveal_type(f1())  # revealed: int | str
+reveal_type(f2())  # revealed: tuple[int, str]
 ```
 
 ## Partial
 
 ```py
-def f(v: tuple[int, "str"]):
-    reveal_type(v)  # revealed: tuple[int, str]
+def f() -> tuple[int, "str"]:
+    return 1
+
+reveal_type(f())  # revealed: tuple[int, str]
 ```
 
 ## Deferred
 
 ```py
-def f(v: "Foo"):
-    reveal_type(v)  # revealed: Foo
+def f() -> "Foo":
+    return Foo()
 
-class Foo: ...
+class Foo:
+    pass
+
+reveal_type(f())  # revealed: Foo
 ```
 
 ## Deferred (undefined)
 
 ```py
 # error: [unresolved-reference]
-def f(v: "Foo"):
-    reveal_type(v)  # revealed: Unknown
+def f() -> "Foo":
+    pass
+
+reveal_type(f())  # revealed: Unknown
 ```
 
 ## Partial deferred
 
 ```py
-def f(v: int | "Foo"):
-    reveal_type(v)  # revealed: int | Foo
+def f() -> int | "Foo":
+    return 1
 
-class Foo: ...
+class Foo:
+    pass
+
+reveal_type(f())  # revealed: int | Foo
 ```
 
 ## `typing.Literal`
@@ -60,43 +79,65 @@ class Foo: ...
 ```py
 from typing import Literal
 
-def f1(v: Literal["Foo", "Bar"], w: 'Literal["Foo", "Bar"]'):
-    reveal_type(v)  # revealed: Literal["Foo", "Bar"]
-    reveal_type(w)  # revealed: Literal["Foo", "Bar"]
+def f1() -> Literal["Foo", "Bar"]:
+    return "Foo"
 
-class Foo: ...
+def f2() -> 'Literal["Foo", "Bar"]':
+    return "Foo"
+
+class Foo:
+    pass
+
+reveal_type(f1())  # revealed: Literal["Foo", "Bar"]
+reveal_type(f2())  # revealed: Literal["Foo", "Bar"]
 ```
 
 ## Various string kinds
 
 ```py
-def f1(
-    # error: [raw-string-type-annotation] "Type expressions cannot use raw string literal"
-    a: r"int",
-    # error: [fstring-type-annotation] "Type expressions cannot use f-strings"
-    b: f"int",
-    # error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
-    c: b"int",
-    d: "int",
-    # error: [implicit-concatenated-string-type-annotation] "Type expressions cannot span multiple string literals"
-    e: "in" "t",
-    # error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
-    f: "\N{LATIN SMALL LETTER I}nt",
-    # error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
-    g: "\x69nt",
-    h: """int""",
-    # error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
-    i: "b'int'",
-):
-    reveal_type(a)  # revealed: Unknown
-    reveal_type(b)  # revealed: Unknown
-    reveal_type(c)  # revealed: Unknown
-    reveal_type(d)  # revealed: int
-    reveal_type(e)  # revealed: Unknown
-    reveal_type(f)  # revealed: Unknown
-    reveal_type(g)  # revealed: Unknown
-    reveal_type(h)  # revealed: int
-    reveal_type(i)  # revealed: Unknown
+# error: [raw-string-type-annotation] "Type expressions cannot use raw string literal"
+def f1() -> r"int":
+    return 1
+
+# error: [fstring-type-annotation] "Type expressions cannot use f-strings"
+def f2() -> f"int":
+    return 1
+
+# error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
+def f3() -> b"int":
+    return 1
+
+def f4() -> "int":
+    return 1
+
+# error: [implicit-concatenated-string-type-annotation] "Type expressions cannot span multiple string literals"
+def f5() -> "in" "t":
+    return 1
+
+# error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
+def f6() -> "\N{LATIN SMALL LETTER I}nt":
+    return 1
+
+# error: [escape-character-in-forward-annotation] "Type expressions cannot contain escape characters"
+def f7() -> "\x69nt":
+    return 1
+
+def f8() -> """int""":
+    return 1
+
+# error: [byte-string-type-annotation] "Type expressions cannot use bytes literal"
+def f9() -> "b'int'":
+    return 1
+
+reveal_type(f1())  # revealed: Unknown
+reveal_type(f2())  # revealed: Unknown
+reveal_type(f3())  # revealed: Unknown
+reveal_type(f4())  # revealed: int
+reveal_type(f5())  # revealed: Unknown
+reveal_type(f6())  # revealed: Unknown
+reveal_type(f7())  # revealed: Unknown
+reveal_type(f8())  # revealed: int
+reveal_type(f9())  # revealed: Unknown
 ```
 
 ## Various string kinds in `typing.Literal`
@@ -104,8 +145,10 @@ def f1(
 ```py
 from typing import Literal
 
-def f(v: Literal["a", r"b", b"c", "d" "e", "\N{LATIN SMALL LETTER F}", "\x67", """h"""]):
-    reveal_type(v)  # revealed: Literal["a", "b", "de", "f", "g", "h"] | Literal[b"c"]
+def f() -> Literal["a", r"b", b"c", "d" "e", "\N{LATIN SMALL LETTER F}", "\x67", """h"""]:
+    return "normal"
+
+reveal_type(f())  # revealed: Literal["a", "b", "de", "f", "g", "h"] | Literal[b"c"]
 ```
 
 ## Class variables
@@ -132,7 +175,8 @@ c: "Foo"
 # error: [invalid-assignment] "Object of type `Literal[1]` is not assignable to `Foo`"
 d: "Foo" = 1
 
-class Foo: ...
+class Foo:
+    pass
 
 c = Foo()
 

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

@@ -1,71 +0,0 @@
-# Unsupported special forms
-
-## Not yet supported
-
-Several special forms are unsupported by red-knot currently. However, we also don't emit
-false-positive errors if you use one in an annotation:
-
-```py
-from typing_extensions import Self, TypeVarTuple, Unpack, TypeGuard, TypeIs, Concatenate, ParamSpec, TypeAlias, Callable, TypeVar
-
-P = ParamSpec("P")
-Ts = TypeVarTuple("Ts")
-R_co = TypeVar("R_co", covariant=True)
-
-Alias: TypeAlias = int
-
-def f(*args: Unpack[Ts]) -> tuple[Unpack[Ts]]:
-    # TODO: should understand the annotation
-    reveal_type(args)  # revealed: tuple
-
-    reveal_type(Alias)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-
-def g() -> TypeGuard[int]: ...
-def h() -> TypeIs[int]: ...
-def i(callback: Callable[Concatenate[int, P], R_co], *args: P.args, **kwargs: P.kwargs) -> R_co:
-    # TODO: should understand the annotation
-    reveal_type(args)  # revealed: tuple
-
-    # TODO: should understand the annotation
-    reveal_type(kwargs)  # revealed: dict
-
-    return callback(42, *args, **kwargs)
-
-class Foo:
-    def method(self, x: Self):
-        reveal_type(x)  # revealed: @Todo(Unsupported or invalid type in a type expression)
-```
-
-## Inheritance
-
-You can't inherit from most of these. `typing.Callable` is an exception.
-
-```py
-from typing import Callable
-from typing_extensions import Self, Unpack, TypeGuard, TypeIs, Concatenate
-
-class A(Self): ...  # error: [invalid-base]
-class B(Unpack): ...  # error: [invalid-base]
-class C(TypeGuard): ...  # error: [invalid-base]
-class D(TypeIs): ...  # error: [invalid-base]
-class E(Concatenate): ...  # error: [invalid-base]
-class F(Callable): ...
-
-reveal_type(F.__mro__)  # revealed: tuple[Literal[F], @Todo(Support for more typing aliases as base classes), Literal[object]]
-```
-
-## Subscriptability
-
-Some of these are not subscriptable:
-
-```py
-from typing_extensions import Self, TypeAlias
-
-X: TypeAlias[T] = int  # error: [invalid-type-form]
-
-class Foo[T]:
-    # error: [invalid-type-form] "Special form `typing.Self` expected no type parameter"
-    # error: [invalid-type-form] "Special form `typing.Self` expected no type parameter"
-    def method(self: Self[int]) -> Self[int]:
-        reveal_type(self)  # revealed: Unknown
-```

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

@@ -1,37 +0,0 @@
-# Unsupported type qualifiers
-
-## Not yet supported
-
-Several type qualifiers are unsupported by red-knot currently. However, we also don't emit
-false-positive errors if you use one in an annotation:
-
-```py
-from typing_extensions import Final, ClassVar, Required, NotRequired, ReadOnly, TypedDict
-
-X: Final = 42
-Y: Final[int] = 42
-
-class Foo:
-    A: ClassVar[int] = 42
-
-# TODO: `TypedDict` is actually valid as a base
-# error: [invalid-base]
-class Bar(TypedDict):
-    x: Required[int]
-    y: NotRequired[str]
-    z: ReadOnly[bytes]
-```
-
-## Inheritance
-
-You can't inherit from a type qualifier.
-
-```py
-from typing_extensions import Final, ClassVar, Required, NotRequired, ReadOnly
-
-class A(Final): ...  # error: [invalid-base]
-class B(ClassVar): ...  # error: [invalid-base]
-class C(Required): ...  # error: [invalid-base]
-class D(NotRequired): ...  # error: [invalid-base]
-class E(ReadOnly): ...  # error: [invalid-base]
-```

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

@@ -78,10 +78,20 @@ c: tuple[str | int, str] = ([], "foo")
 ## PEP-604 annotations are supported
 
 ```py
-def foo(v: str | int | None, w: str | str | None, x: str | str):
-    reveal_type(v)  # revealed: str | int | None
-    reveal_type(w)  # revealed: str | None
-    reveal_type(x)  # revealed: str
+def foo() -> str | int | None:
+    return None
+
+reveal_type(foo())  # revealed: str | int | None
+
+def bar() -> str | str | None:
+    return None
+
+reveal_type(bar())  # revealed: str | None
+
+def baz() -> str | str:
+    return "Hello, world!"
+
+reveal_type(baz())  # revealed: str
 ```
 
 ## Attribute expressions in type annotations are understood
@@ -108,7 +118,8 @@ from __future__ import annotations
 
 x: Foo
 
-class Foo: ...
+class Foo:
+    pass
 
 x = Foo()
 reveal_type(x)  # revealed: Foo
@@ -119,7 +130,8 @@ reveal_type(x)  # revealed: Foo
 ```pyi path=main.pyi
 x: Foo
 
-class Foo: ...
+class Foo:
+    pass
 
 x = Foo()
 reveal_type(x)  # revealed: Foo

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

@@ -49,116 +49,134 @@ reveal_type(x)  # revealed: int
 ## Method union
 
 ```py
-def _(flag: bool):
-    class Foo:
-        if flag:
-            def __iadd__(self, other: int) -> str:
-                return "Hello, world!"
-        else:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True
 
-    f = Foo()
-    f += 12
+flag = bool_instance()
 
-    reveal_type(f)  # revealed: str | int
+class Foo:
+    if bool_instance():
+        def __iadd__(self, other: int) -> str:
+            return "Hello, world!"
+    else:
+        def __iadd__(self, other: int) -> int:
+            return 42
+
+f = Foo()
+f += 12
+
+reveal_type(f)  # revealed: str | int
 ```
 
 ## Partially bound `__iadd__`
 
 ```py
-def _(flag: bool):
-    class Foo:
-        if flag:
-            def __iadd__(self, other: str) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True
 
-    f = Foo()
+class Foo:
+    if bool_instance():
+        def __iadd__(self, other: str) -> int:
+            return 42
 
-    # TODO: We should emit an `unsupported-operator` error here, possibly with the information
-    # that `Foo.__iadd__` may be unbound as additional context.
-    f += "Hello, world!"
+f = Foo()
 
-    reveal_type(f)  # revealed: int | Unknown
+# TODO: We should emit an `unsupported-operator` error here, possibly with the information
+# that `Foo.__iadd__` may be unbound as additional context.
+f += "Hello, world!"
+
+reveal_type(f)  # revealed: int | Unknown
 ```
 
 ## Partially bound with `__add__`
 
 ```py
-def _(flag: bool):
-    class Foo:
-        def __add__(self, other: str) -> str:
-            return "Hello, world!"
-        if flag:
-            def __iadd__(self, other: str) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True
 
-    f = Foo()
-    f += "Hello, world!"
+class Foo:
+    def __add__(self, other: str) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: str) -> int:
+            return 42
 
-    reveal_type(f)  # revealed: int | str
+f = Foo()
+f += "Hello, world!"
+
+reveal_type(f)  # revealed: int | str
 ```
 
 ## Partially bound target union
 
 ```py
-def _(flag1: bool, flag2: bool):
-    class Foo:
-        def __add__(self, other: int) -> str:
-            return "Hello, world!"
-        if flag1:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True
 
-    if flag2:
-        f = Foo()
-    else:
-        f = 42.0
-    f += 12
+class Foo:
+    def __add__(self, other: int) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: int) -> int:
+            return 42
 
-    reveal_type(f)  # revealed: int | str | float
+if bool_instance():
+    f = Foo()
+else:
+    f = 42.0
+f += 12
+
+reveal_type(f)  # revealed: int | str | float
 ```
 
 ## Target union
 
 ```py
-def _(flag: bool):
-    class Foo:
-        def __iadd__(self, other: int) -> str:
-            return "Hello, world!"
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        f = Foo()
-    else:
-        f = 42.0
-    f += 12
+flag = bool_instance()
 
-    reveal_type(f)  # revealed: str | float
+class Foo:
+    def __iadd__(self, other: int) -> str:
+        return "Hello, world!"
+
+if flag:
+    f = Foo()
+else:
+    f = 42.0
+f += 12
+
+reveal_type(f)  # revealed: str | float
 ```
 
 ## Partially bound target union with `__add__`
 
 ```py
-def f(flag: bool, flag2: bool):
-    class Foo:
-        def __add__(self, other: int) -> str:
-            return "Hello, world!"
-        if flag:
-            def __iadd__(self, other: int) -> int:
-                return 42
+def bool_instance() -> bool:
+    return True
 
-    class Bar:
-        def __add__(self, other: int) -> bytes:
-            return b"Hello, world!"
+flag = bool_instance()
 
-        def __iadd__(self, other: int) -> float:
-            return 42.0
+class Foo:
+    def __add__(self, other: int) -> str:
+        return "Hello, world!"
+    if bool_instance():
+        def __iadd__(self, other: int) -> int:
+            return 42
 
-    if flag2:
-        f = Foo()
-    else:
-        f = Bar()
-    f += 12
+class Bar:
+    def __add__(self, other: int) -> bytes:
+        return b"Hello, world!"
 
-    reveal_type(f)  # revealed: int | str | float
+    def __iadd__(self, other: int) -> float:
+        return 42.0
+
+if flag:
+    f = Foo()
+else:
+    f = Bar()
+f += 12
+
+reveal_type(f)  # revealed: int | str | float
 ```

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -3,23 +3,27 @@
 ## Union of attributes
 
 ```py
-def _(flag: bool):
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+if flag:
+    class C1:
+        x = 1
+
+else:
+    class C1:
+        x = 2
+
+class C2:
     if flag:
-        class C1:
-            x = 1
-
+        x = 3
     else:
-        class C1:
-            x = 2
+        x = 4
 
-    class C2:
-        if flag:
-            x = 3
-        else:
-            x = 4
-
-    reveal_type(C1.x)  # revealed: Literal[1, 2]
-    reveal_type(C2.x)  # revealed: Literal[3, 4]
+reveal_type(C1.x)  # revealed: Literal[1, 2]
+reveal_type(C2.x)  # revealed: Literal[3, 4]
 ```
 
 ## Inherited attributes
@@ -64,19 +68,24 @@ reveal_type(A.X)  # revealed: Literal[42]
 In this example, the `x` attribute is not defined in the `C2` element of the union:
 
 ```py
-def _(flag1: bool, flag2: bool):
-    class C1:
-        x = 1
+def bool_instance() -> bool:
+    return True
 
-    class C2: ...
+class C1:
+    x = 1
 
-    class C3:
-        x = 3
+class C2: ...
 
-    C = C1 if flag1 else C2 if flag2 else C3
+class C3:
+    x = 3
 
-    # error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-    reveal_type(C.x)  # revealed: Literal[1, 3]
+flag1 = bool_instance()
+flag2 = bool_instance()
+
+C = C1 if flag1 else C2 if flag2 else C3
+
+# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
+reveal_type(C.x)  # revealed: Literal[1, 3]
 ```
 
 ### Possibly-unbound within a class
@@ -85,21 +94,26 @@ We raise the same diagnostic if the attribute is possibly-unbound in at least on
 union:
 
 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    class C1:
-        x = 1
+def bool_instance() -> bool:
+    return True
 
-    class C2:
-        if flag:
-            x = 2
+class C1:
+    x = 1
 
-    class C3:
-        x = 3
+class C2:
+    if bool_instance():
+        x = 2
 
-    C = C1 if flag1 else C2 if flag2 else C3
+class C3:
+    x = 3
 
-    # error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
-    reveal_type(C.x)  # revealed: Literal[1, 2, 3]
+flag1 = bool_instance()
+flag2 = bool_instance()
+
+C = C1 if flag1 else C2 if flag2 else C3
+
+# error: [possibly-unbound-attribute] "Attribute `x` on type `Literal[C1, C2, C3]` is possibly unbound"
+reveal_type(C.x)  # revealed: Literal[1, 2, 3]
 ```
 
 ## Unions with all paths unbound
@@ -107,51 +121,16 @@ def _(flag: bool, flag1: bool, flag2: bool):
 If the symbol is unbound in all elements of the union, we detect that:
 
 ```py
-def _(flag: bool):
-    class C1: ...
-    class C2: ...
-    C = C1 if flag else C2
+def bool_instance() -> bool:
+    return True
 
-    # error: [unresolved-attribute] "Type `Literal[C1, C2]` has no attribute `x`"
-    reveal_type(C.x)  # revealed: Unknown
-```
-
-## Objects of all types have a `__class__` method
-
-```py
-import typing_extensions
-
-reveal_type(typing_extensions.__class__)  # revealed: Literal[ModuleType]
-
-a = 42
-reveal_type(a.__class__)  # revealed: Literal[int]
-
-b = "42"
-reveal_type(b.__class__)  # revealed: Literal[str]
-
-c = b"42"
-reveal_type(c.__class__)  # revealed: Literal[bytes]
-
-d = True
-reveal_type(d.__class__)  # revealed: Literal[bool]
-
-e = (42, 42)
-reveal_type(e.__class__)  # revealed: Literal[tuple]
-
-def f(a: int, b: typing_extensions.LiteralString, c: int | str, d: type[str]):
-    reveal_type(a.__class__)  # revealed: type[int]
-    reveal_type(b.__class__)  # revealed: Literal[str]
-    reveal_type(c.__class__)  # revealed: type[int] | type[str]
-
-    # `type[type]`, a.k.a., either the class `type` or some subclass of `type`.
-    # It would be incorrect to infer `Literal[type]` here,
-    # as `c` could be some subclass of `str` with a custom metaclass.
-    # All we know is that the metaclass must be a (non-strict) subclass of `type`.
-    reveal_type(d.__class__)  # revealed: type[type]
-
-reveal_type(f.__class__)  # revealed: Literal[FunctionType]
-
-class Foo: ...
-
-reveal_type(Foo.__class__)  # revealed: Literal[type]
+class C1: ...
+class C2: ...
+
+flag = bool_instance()
+
+C = C1 if flag else C2
+
+# error: [unresolved-attribute] "Type `Literal[C1, C2]` has no attribute `x`"
+reveal_type(C.x)  # revealed: Unknown
 ```

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

@@ -281,12 +281,20 @@ reveal_type(42 + 4.2)  # revealed: int
 # TODO should be complex, need to check arg type and fall back to `rhs.__radd__`
 reveal_type(3 + 3j)  # revealed: int
 
-def _(x: bool, y: int):
-    reveal_type(x + y)  # revealed: int
-    reveal_type(4.2 + x)  # revealed: float
+def returns_int() -> int:
+    return 42
 
-    # TODO should be float, need to check arg type and fall back to `rhs.__radd__`
-    reveal_type(y + 4.12)  # revealed: int
+def returns_bool() -> bool:
+    return True
+
+x = returns_bool()
+y = returns_int()
+
+reveal_type(x + y)  # revealed: int
+reveal_type(4.2 + x)  # revealed: float
+
+# TODO should be float, need to check arg type and fall back to `rhs.__radd__`
+reveal_type(y + 4.12)  # revealed: int
 ```
 
 ## With literal types

crates/red_knot_python_semantic/resources/mdtest/boolean/short_circuit.md

@@ -7,25 +7,29 @@ Similarly, in `and` expressions, if the left-hand side is falsy, the right-hand
 evaluated.
 
 ```py
-def _(flag: bool):
-    if flag or (x := 1):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True
 
-    if flag and (x := 1):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
+if bool_instance() or (x := 1):
+    # error: [possibly-unresolved-reference]
+    reveal_type(x)  # revealed: Literal[1]
+
+if bool_instance() and (x := 1):
+    # error: [possibly-unresolved-reference]
+    reveal_type(x)  # revealed: Literal[1]
 ```
 
 ## First expression is always evaluated
 
 ```py
-def _(flag: bool):
-    if (x := 1) or flag:
-        reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True
 
-    if (x := 1) and flag:
-        reveal_type(x)  # revealed: Literal[1]
+if (x := 1) or bool_instance():
+    reveal_type(x)  # revealed: Literal[1]
+
+if (x := 1) and bool_instance():
+    reveal_type(x)  # revealed: Literal[1]
 ```
 
 ## Statically known truthiness
@@ -45,26 +49,30 @@ if True and (x := 1):
 ## Later expressions can always use variables from earlier expressions
 
 ```py
-def _(flag: bool):
-    flag or (x := 1) or reveal_type(x)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True
 
-    # error: [unresolved-reference]
-    flag or reveal_type(y) or (y := 1)  # revealed: Unknown
+bool_instance() or (x := 1) or reveal_type(x)  # revealed: Literal[1]
+
+# error: [unresolved-reference]
+bool_instance() or reveal_type(y) or (y := 1)  # revealed: Unknown
 ```
 
 ## Nested expressions
 
 ```py
-def _(flag1: bool, flag2: bool):
-    if flag1 or ((x := 1) and flag2):
-        # error: [possibly-unresolved-reference]
-        reveal_type(x)  # revealed: Literal[1]
-
-    if ((y := 1) and flag1) or flag2:
-        reveal_type(y)  # revealed: Literal[1]
+def bool_instance() -> bool:
+    return True
 
+if bool_instance() or ((x := 1) and bool_instance()):
     # error: [possibly-unresolved-reference]
-    if (flag1 and (z := 1)) or reveal_type(z):  # revealed: Literal[1]
-        # error: [possibly-unresolved-reference]
-        reveal_type(z)  # revealed: Literal[1]
+    reveal_type(x)  # revealed: Literal[1]
+
+if ((y := 1) and bool_instance()) or bool_instance():
+    reveal_type(y)  # revealed: Literal[1]
+
+# error: [possibly-unresolved-reference]
+if (bool_instance() and (z := 1)) or reveal_type(z):  # revealed: Literal[1]
+    # error: [possibly-unresolved-reference]
+    reveal_type(z)  # revealed: Literal[1]
 ```

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

@@ -22,27 +22,29 @@ reveal_type(b)  # revealed: Unknown
 ## Possibly unbound `__call__` method
 
 ```py
-def _(flag: bool):
-    class PossiblyNotCallable:
-        if flag:
-            def __call__(self) -> int: ...
+def flag() -> bool: ...
 
-    a = PossiblyNotCallable()
-    result = a()  # error: "Object of type `PossiblyNotCallable` is not callable (possibly unbound `__call__` method)"
-    reveal_type(result)  # revealed: int
+class PossiblyNotCallable:
+    if flag():
+        def __call__(self) -> int: ...
+
+a = PossiblyNotCallable()
+result = a()  # error: "Object of type `PossiblyNotCallable` is not callable (possibly unbound `__call__` method)"
+reveal_type(result)  # revealed: int
 ```
 
 ## Possibly unbound callable
 
 ```py
-def _(flag: bool):
-    if flag:
-        class PossiblyUnbound:
-            def __call__(self) -> int: ...
+def flag() -> bool: ...
 
-    # error: [possibly-unresolved-reference]
-    a = PossiblyUnbound()
-    reveal_type(a())  # revealed: int
+if flag():
+    class PossiblyUnbound:
+        def __call__(self) -> int: ...
+
+# error: [possibly-unresolved-reference]
+a = PossiblyUnbound()
+reveal_type(a())  # revealed: int
 ```
 
 ## Non-callable `__call__`
@@ -59,14 +61,15 @@ reveal_type(a())  # revealed: Unknown
 ## Possibly non-callable `__call__`
 
 ```py
-def _(flag: bool):
-    class NonCallable:
-        if flag:
-            __call__ = 1
-        else:
-            def __call__(self) -> int: ...
+def flag() -> bool: ...
 
-    a = NonCallable()
-    # error: "Object of type `Literal[1] | Literal[__call__]` is not callable (due to union element `Literal[1]`)"
-    reveal_type(a())  # revealed: Unknown | int
+class NonCallable:
+    if flag():
+        __call__ = 1
+    else:
+        def __call__(self) -> int: ...
+
+a = NonCallable()
+# error: "Object of type `Literal[1] | Literal[__call__]` is not callable (due to union element `Literal[1]`)"
+reveal_type(a())  # revealed: Unknown | int
 ```

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

@@ -57,10 +57,12 @@ x = nonsense()  # error: "Object of type `Literal[123]` is not callable"
 ## Potentially unbound function
 
 ```py
-def _(flag: bool):
-    if flag:
-        def foo() -> int:
-            return 42
-    # error: [possibly-unresolved-reference]
-    reveal_type(foo())  # revealed: int
+def flag() -> bool: ...
+
+if flag():
+    def foo() -> int:
+        return 42
+
+# error: [possibly-unresolved-reference]
+reveal_type(foo())  # revealed: int
 ```

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

@@ -3,14 +3,22 @@
 ## Union of return types
 
 ```py
-def _(flag: bool):
-    if flag:
-        def f() -> int:
-            return 1
-    else:
-        def f() -> str:
-            return "foo"
-    reveal_type(f())  # revealed: int | str
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+if flag:
+
+    def f() -> int:
+        return 1
+
+else:
+
+    def f() -> str:
+        return "foo"
+
+reveal_type(f())  # revealed: int | str
 ```
 
 ## Calling with an unknown union
@@ -18,10 +26,13 @@ def _(flag: bool):
 ```py
 from nonexistent import f  # error: [unresolved-import] "Cannot resolve import `nonexistent`"
 
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+flag = bool_instance()
+
+if flag:
+
     def f() -> int:
         return 1
 
@@ -33,14 +44,20 @@ reveal_type(f())  # revealed: Unknown | int
 Calling a union with a non-callable element should emit a diagnostic.
 
 ```py
-def _(flag: bool):
-    if flag:
-        f = 1
-    else:
-        def f() -> int:
-            return 1
-    x = f()  # error: "Object of type `Literal[1] | Literal[f]` is not callable (due to union element `Literal[1]`)"
-    reveal_type(x)  # revealed: Unknown | int
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+if flag:
+    f = 1
+else:
+
+    def f() -> int:
+        return 1
+
+x = f()  # error: "Object of type `Literal[1] | Literal[f]` is not callable (due to union element `Literal[1]`)"
+reveal_type(x)  # revealed: Unknown | int
 ```
 
 ## Multiple non-callable elements in a union
@@ -48,17 +65,23 @@ def _(flag: bool):
 Calling a union with multiple non-callable elements should mention all of them in the diagnostic.
 
 ```py
-def _(flag: bool, flag2: bool):
-    if flag:
-        f = 1
-    elif flag2:
-        f = "foo"
-    else:
-        def f() -> int:
-            return 1
-    # error: "Object of type `Literal[1] | Literal["foo"] | Literal[f]` is not callable (due to union elements Literal[1], Literal["foo"])"
-    # revealed: Unknown | int
-    reveal_type(f())
+def bool_instance() -> bool:
+    return True
+
+flag, flag2 = bool_instance(), bool_instance()
+
+if flag:
+    f = 1
+elif flag2:
+    f = "foo"
+else:
+
+    def f() -> int:
+        return 1
+
+# error: "Object of type `Literal[1] | Literal["foo"] | Literal[f]` is not callable (due to union elements Literal[1], Literal["foo"])"
+# revealed: Unknown | int
+reveal_type(f())
 ```
 
 ## All non-callable union elements
@@ -66,12 +89,16 @@ def _(flag: bool, flag2: bool):
 Calling a union with no callable elements can emit a simpler diagnostic.
 
 ```py
-def _(flag: bool):
-    if flag:
-        f = 1
-    else:
-        f = "foo"
+def bool_instance() -> bool:
+    return True
 
-    x = f()  # error: "Object of type `Literal[1] | Literal["foo"]` is not callable"
-    reveal_type(x)  # revealed: Unknown
+flag = bool_instance()
+
+if flag:
+    f = 1
+else:
+    f = "foo"
+
+x = f()  # error: "Object of type `Literal[1] | Literal["foo"]` is not callable"
+reveal_type(x)  # revealed: Unknown
 ```

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

@@ -3,31 +3,38 @@
 ```py
 class A: ...
 
-def _(a1: A, a2: A, o: object):
-    n1 = None
-    n2 = None
+def get_a() -> A: ...
+def get_object() -> object: ...
 
-    reveal_type(a1 is a1)  # revealed: bool
-    reveal_type(a1 is a2)  # revealed: bool
+a1 = get_a()
+a2 = get_a()
 
-    reveal_type(n1 is n1)  # revealed: Literal[True]
-    reveal_type(n1 is n2)  # revealed: Literal[True]
+n1 = None
+n2 = None
 
-    reveal_type(a1 is n1)  # revealed: Literal[False]
-    reveal_type(n1 is a1)  # revealed: Literal[False]
+o = get_object()
 
-    reveal_type(a1 is o)  # revealed: bool
-    reveal_type(n1 is o)  # revealed: bool
+reveal_type(a1 is a1)  # revealed: bool
+reveal_type(a1 is a2)  # revealed: bool
 
-    reveal_type(a1 is not a1)  # revealed: bool
-    reveal_type(a1 is not a2)  # revealed: bool
+reveal_type(n1 is n1)  # revealed: Literal[True]
+reveal_type(n1 is n2)  # revealed: Literal[True]
 
-    reveal_type(n1 is not n1)  # revealed: Literal[False]
-    reveal_type(n1 is not n2)  # revealed: Literal[False]
+reveal_type(a1 is n1)  # revealed: Literal[False]
+reveal_type(n1 is a1)  # revealed: Literal[False]
 
-    reveal_type(a1 is not n1)  # revealed: Literal[True]
-    reveal_type(n1 is not a1)  # revealed: Literal[True]
+reveal_type(a1 is o)  # revealed: bool
+reveal_type(n1 is o)  # revealed: bool
 
-    reveal_type(a1 is not o)  # revealed: bool
-    reveal_type(n1 is not o)  # revealed: bool
+reveal_type(a1 is not a1)  # revealed: bool
+reveal_type(a1 is not a2)  # revealed: bool
+
+reveal_type(n1 is not n1)  # revealed: Literal[False]
+reveal_type(n1 is not n2)  # revealed: Literal[False]
+
+reveal_type(a1 is not n1)  # revealed: Literal[True]
+reveal_type(n1 is not a1)  # revealed: Literal[True]
+
+reveal_type(a1 is not o)  # revealed: bool
+reveal_type(n1 is not o)  # revealed: bool
 ```

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

@@ -312,9 +312,17 @@ reveal_type(1 <= 2j)  # revealed: bool
 reveal_type(1 > 2j)  # revealed: bool
 reveal_type(1 >= 2j)  # revealed: bool
 
-def f(x: bool, y: int):
-    reveal_type(x < y)  # revealed: bool
-    reveal_type(y < x)  # revealed: bool
-    reveal_type(4.2 < x)  # revealed: bool
-    reveal_type(x < 4.2)  # revealed: bool
+def bool_instance() -> bool:
+    return True
+
+def int_instance() -> int:
+    return 42
+
+x = bool_instance()
+y = int_instance()
+
+reveal_type(x < y)  # revealed: bool
+reveal_type(y < x)  # revealed: bool
+reveal_type(4.2 < x)  # revealed: bool
+reveal_type(x < 4.2)  # revealed: bool
 ```

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

@@ -20,8 +20,10 @@ reveal_type(1 <= "" and 0 < 1)  # revealed: bool
 
 ```py
 # TODO: implement lookup of `__eq__` on typeshed `int` stub.
-def _(a: int, b: int):
-    reveal_type(1 == a)  # revealed: bool
-    reveal_type(9 < a)  # revealed: bool
-    reveal_type(a < b)  # revealed: bool
+def int_instance() -> int:
+    return 42
+
+reveal_type(1 == int_instance())  # revealed: bool
+reveal_type(9 < int_instance())  # revealed: bool
+reveal_type(int_instance() < int_instance())  # revealed: bool
 ```

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

@@ -14,19 +14,21 @@ class Child1(Base):
 
 class Child2(Base): ...
 
-def _(x: Base):
-    c1 = Child1()
+def get_base() -> Base: ...
 
-    # Create an intersection type through narrowing:
-    if isinstance(x, Child1):
-        if isinstance(x, Child2):
-            reveal_type(x)  # revealed: Child1 & Child2
+x = get_base()
+c1 = Child1()
 
-            reveal_type(x == 1)  # revealed: Literal[True]
+# Create an intersection type through narrowing:
+if isinstance(x, Child1):
+    if isinstance(x, Child2):
+        reveal_type(x)  # revealed: Child1 & Child2
 
-            # Other comparison operators fall back to the base type:
-            reveal_type(x > 1)  # revealed: bool
-            reveal_type(x is c1)  # revealed: bool
+        reveal_type(x == 1)  # revealed: Literal[True]
+
+        # Other comparison operators fall back to the base type:
+        reveal_type(x > 1)  # revealed: bool
+        reveal_type(x is c1)  # revealed: bool
 ```
 
 ## Negative contributions
@@ -71,15 +73,18 @@ if x != "abc":
 #### Integers
 
 ```py
-def _(x: int):
-    if x != 1:
-        reveal_type(x)  # revealed: int & ~Literal[1]
+def get_int() -> int: ...
 
-        reveal_type(x != 1)  # revealed: Literal[True]
-        reveal_type(x != 2)  # revealed: bool
+x = get_int()
 
-        reveal_type(x == 1)  # revealed: Literal[False]
-        reveal_type(x == 2)  # revealed: bool
+if x != 1:
+    reveal_type(x)  # revealed: int & ~Literal[1]
+
+    reveal_type(x != 1)  # revealed: Literal[True]
+    reveal_type(x != 2)  # revealed: bool
+
+    reveal_type(x == 1)  # revealed: Literal[False]
+    reveal_type(x == 2)  # revealed: bool
 ```
 
 ### Identity comparisons
@@ -87,15 +92,18 @@ def _(x: int):
 ```py
 class A: ...
 
-def _(o: object):
-    a = A()
-    n = None
+def get_object() -> object: ...
 
-    if o is not None:
-        reveal_type(o)  # revealed: object & ~None
+o = object()
 
-        reveal_type(o is n)  # revealed: Literal[False]
-        reveal_type(o is not n)  # revealed: Literal[True]
+a = A()
+n = None
+
+if o is not None:
+    reveal_type(o)  # revealed: object & ~None
+
+    reveal_type(o is n)  # revealed: Literal[False]
+    reveal_type(o is not n)  # revealed: Literal[True]
 ```
 
 ## Diagnostics
@@ -111,13 +119,16 @@ class Container:
 
 class NonContainer: ...
 
-def _(x: object):
-    if isinstance(x, Container):
-        if isinstance(x, NonContainer):
-            reveal_type(x)  # revealed: Container & NonContainer
+def get_object() -> object: ...
 
-            # error: [unsupported-operator] "Operator `in` is not supported for types `int` and `NonContainer`"
-            reveal_type(2 in x)  # revealed: bool
+x = get_object()
+
+if isinstance(x, Container):
+    if isinstance(x, NonContainer):
+        reveal_type(x)  # revealed: Container & NonContainer
+
+        # error: [unsupported-operator] "Operator `in` is not supported for types `int` and `NonContainer`"
+        reveal_type(2 in x)  # revealed: bool
 ```
 
 ### Unsupported operators for negative contributions
@@ -131,11 +142,14 @@ class Container:
 
 class NonContainer: ...
 
-def _(x: object):
-    if isinstance(x, Container):
-        if not isinstance(x, NonContainer):
-            reveal_type(x)  # revealed: Container & ~NonContainer
+def get_object() -> object: ...
 
-            # No error here!
-            reveal_type(2 in x)  # revealed: bool
+x = get_object()
+
+if isinstance(x, Container):
+    if not isinstance(x, NonContainer):
+        reveal_type(x)  # revealed: Container & ~NonContainer
+
+        # No error here!
+        reveal_type(2 in x)  # revealed: bool
 ```

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

@@ -3,17 +3,18 @@
 ## String literals
 
 ```py
-def _(x: str):
-    reveal_type("abc" == "abc")  # revealed: Literal[True]
-    reveal_type("ab_cd" <= "ab_ce")  # revealed: Literal[True]
-    reveal_type("abc" in "ab cd")  # revealed: Literal[False]
-    reveal_type("" not in "hello")  # revealed: Literal[False]
-    reveal_type("--" is "--")  # revealed: bool
-    reveal_type("A" is "B")  # revealed: Literal[False]
-    reveal_type("--" is not "--")  # revealed: bool
-    reveal_type("A" is not "B")  # revealed: Literal[True]
-    reveal_type(x < "...")  # revealed: bool
+def str_instance() -> str: ...
 
-    # ensure we're not comparing the interned salsa symbols, which compare by order of declaration.
-    reveal_type("ab" < "ab_cd")  # revealed: Literal[True]
+reveal_type("abc" == "abc")  # revealed: Literal[True]
+reveal_type("ab_cd" <= "ab_ce")  # revealed: Literal[True]
+reveal_type("abc" in "ab cd")  # revealed: Literal[False]
+reveal_type("" not in "hello")  # revealed: Literal[False]
+reveal_type("--" is "--")  # revealed: bool
+reveal_type("A" is "B")  # revealed: Literal[False]
+reveal_type("--" is not "--")  # revealed: bool
+reveal_type("A" is not "B")  # revealed: Literal[True]
+reveal_type(str_instance() < "...")  # revealed: bool
+
+# ensure we're not comparing the interned salsa symbols, which compare by order of declaration.
+reveal_type("ab" < "ab_cd")  # revealed: Literal[True]
 ```

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

@@ -58,23 +58,28 @@ reveal_type(c >= d)  # revealed: Literal[True]
 #### Results with Ambiguity
 
 ```py
-def _(x: bool, y: int):
-    a = (x,)
-    b = (y,)
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(a == a)  # revealed: bool
-    reveal_type(a != a)  # revealed: bool
-    reveal_type(a < a)  # revealed: bool
-    reveal_type(a <= a)  # revealed: bool
-    reveal_type(a > a)  # revealed: bool
-    reveal_type(a >= a)  # revealed: bool
+def int_instance() -> int:
+    return 42
 
-    reveal_type(a == b)  # revealed: bool
-    reveal_type(a != b)  # revealed: bool
-    reveal_type(a < b)  # revealed: bool
-    reveal_type(a <= b)  # revealed: bool
-    reveal_type(a > b)  # revealed: bool
-    reveal_type(a >= b)  # revealed: bool
+a = (bool_instance(),)
+b = (int_instance(),)
+
+reveal_type(a == a)  # revealed: bool
+reveal_type(a != a)  # revealed: bool
+reveal_type(a < a)  # revealed: bool
+reveal_type(a <= a)  # revealed: bool
+reveal_type(a > a)  # revealed: bool
+reveal_type(a >= a)  # revealed: bool
+
+reveal_type(a == b)  # revealed: bool
+reveal_type(a != b)  # revealed: bool
+reveal_type(a < b)  # revealed: bool
+reveal_type(a <= b)  # revealed: bool
+reveal_type(a > b)  # revealed: bool
+reveal_type(a >= b)  # revealed: bool
 ```
 
 #### Comparison Unsupported
@@ -192,7 +197,7 @@ reveal_type((A(), B()) < (A(), B()))  # revealed: float | set | Literal[False]
 
 #### Special Handling of Eq and NotEq in Lexicographic Comparisons
 
-> Example: `(<int instance>, "foo") == (<int instance>, "bar")`
+> Example: `(int_instance(), "foo") == (int_instance(), "bar")`
 
 `Eq` and `NotEq` have unique behavior compared to other operators in lexicographic comparisons.
 Specifically, for `Eq`, if any non-equal pair exists within the tuples being compared, we can
@@ -203,38 +208,42 @@ In contrast, with operators like `<` and `>`, the comparison must consider each
 sequentially, and the final outcome might remain ambiguous until all pairs are compared.
 
 ```py
-def _(x: str, y: int):
-    reveal_type("foo" == "bar")  # revealed: Literal[False]
-    reveal_type(("foo",) == ("bar",))  # revealed: Literal[False]
-    reveal_type((4, "foo") == (4, "bar"))  # revealed: Literal[False]
-    reveal_type((y, "foo") == (y, "bar"))  # revealed: Literal[False]
+def str_instance() -> str:
+    return "hello"
 
-    a = (x, y, "foo")
+def int_instance() -> int:
+    return 42
 
-    reveal_type(a == a)  # revealed: bool
-    reveal_type(a != a)  # revealed: bool
-    reveal_type(a < a)  # revealed: bool
-    reveal_type(a <= a)  # revealed: bool
-    reveal_type(a > a)  # revealed: bool
-    reveal_type(a >= a)  # revealed: bool
+reveal_type("foo" == "bar")  # revealed: Literal[False]
+reveal_type(("foo",) == ("bar",))  # revealed: Literal[False]
+reveal_type((4, "foo") == (4, "bar"))  # revealed: Literal[False]
+reveal_type((int_instance(), "foo") == (int_instance(), "bar"))  # revealed: Literal[False]
 
-    b = (x, y, "bar")
+a = (str_instance(), int_instance(), "foo")
 
-    reveal_type(a == b)  # revealed: Literal[False]
-    reveal_type(a != b)  # revealed: Literal[True]
-    reveal_type(a < b)  # revealed: bool
-    reveal_type(a <= b)  # revealed: bool
-    reveal_type(a > b)  # revealed: bool
-    reveal_type(a >= b)  # revealed: bool
+reveal_type(a == a)  # revealed: bool
+reveal_type(a != a)  # revealed: bool
+reveal_type(a < a)  # revealed: bool
+reveal_type(a <= a)  # revealed: bool
+reveal_type(a > a)  # revealed: bool
+reveal_type(a >= a)  # revealed: bool
 
-    c = (x, y, "foo", "different_length")
+b = (str_instance(), int_instance(), "bar")
 
-    reveal_type(a == c)  # revealed: Literal[False]
-    reveal_type(a != c)  # revealed: Literal[True]
-    reveal_type(a < c)  # revealed: bool
-    reveal_type(a <= c)  # revealed: bool
-    reveal_type(a > c)  # revealed: bool
-    reveal_type(a >= c)  # revealed: bool
+reveal_type(a == b)  # revealed: Literal[False]
+reveal_type(a != b)  # revealed: Literal[True]
+reveal_type(a < b)  # revealed: bool
+reveal_type(a <= b)  # revealed: bool
+reveal_type(a > b)  # revealed: bool
+reveal_type(a >= b)  # revealed: bool
+
+c = (str_instance(), int_instance(), "foo", "different_length")
+reveal_type(a == c)  # revealed: Literal[False]
+reveal_type(a != c)  # revealed: Literal[True]
+reveal_type(a < c)  # revealed: bool
+reveal_type(a <= c)  # revealed: bool
+reveal_type(a > c)  # revealed: bool
+reveal_type(a >= c)  # revealed: bool
 ```
 
 #### Error Propagation
@@ -243,36 +252,42 @@ Errors occurring within a tuple comparison should propagate outward. However, if
 comparison can clearly conclude before encountering an error, the error should not be raised.
 
 ```py
-def _(n: int, s: str):
-    class A: ...
-    # error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`"
-    A() < A()
-    # error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`"
-    A() <= A()
-    # error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`"
-    A() > A()
-    # error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`"
-    A() >= A()
+def int_instance() -> int:
+    return 42
 
-    a = (0, n, A())
+def str_instance() -> str:
+    return "hello"
 
-    # error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-    reveal_type(a < a)  # revealed: Unknown
-    # error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-    reveal_type(a <= a)  # revealed: Unknown
-    # error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-    reveal_type(a > a)  # revealed: Unknown
-    # error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
-    reveal_type(a >= a)  # revealed: Unknown
+class A: ...
 
-    # Comparison between `a` and `b` should only involve the first elements, `Literal[0]` and `Literal[99999]`,
-    # and should terminate immediately.
-    b = (99999, n, A())
+# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`"
+A() < A()
+# error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`"
+A() <= A()
+# error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`"
+A() > A()
+# error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`"
+A() >= A()
 
-    reveal_type(a < b)  # revealed: Literal[True]
-    reveal_type(a <= b)  # revealed: Literal[True]
-    reveal_type(a > b)  # revealed: Literal[False]
-    reveal_type(a >= b)  # revealed: Literal[False]
+a = (0, int_instance(), A())
+
+# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
+reveal_type(a < a)  # revealed: Unknown
+# error: [unsupported-operator] "Operator `<=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
+reveal_type(a <= a)  # revealed: Unknown
+# error: [unsupported-operator] "Operator `>` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
+reveal_type(a > a)  # revealed: Unknown
+# error: [unsupported-operator] "Operator `>=` is not supported for types `A` and `A`, in comparing `tuple[Literal[0], int, A]` with `tuple[Literal[0], int, A]`"
+reveal_type(a >= a)  # revealed: Unknown
+
+# Comparison between `a` and `b` should only involve the first elements, `Literal[0]` and `Literal[99999]`,
+# and should terminate immediately.
+b = (99999, int_instance(), A())
+
+reveal_type(a < b)  # revealed: Literal[True]
+reveal_type(a <= b)  # revealed: Literal[True]
+reveal_type(a > b)  # revealed: Literal[False]
+reveal_type(a >= b)  # revealed: Literal[False]
 ```
 
 ### Membership Test Comparisons
@@ -280,20 +295,22 @@ def _(n: int, s: str):
 "Membership Test Comparisons" refers to the operators `in` and `not in`.
 
 ```py
-def _(n: int):
-    a = (1, 2)
-    b = ((3, 4), (1, 2))
-    c = ((1, 2, 3), (4, 5, 6))
-    d = ((n, n), (n, n))
+def int_instance() -> int:
+    return 42
 
-    reveal_type(a in b)  # revealed: Literal[True]
-    reveal_type(a not in b)  # revealed: Literal[False]
+a = (1, 2)
+b = ((3, 4), (1, 2))
+c = ((1, 2, 3), (4, 5, 6))
+d = ((int_instance(), int_instance()), (int_instance(), int_instance()))
 
-    reveal_type(a in c)  # revealed: Literal[False]
-    reveal_type(a not in c)  # revealed: Literal[True]
+reveal_type(a in b)  # revealed: Literal[True]
+reveal_type(a not in b)  # revealed: Literal[False]
 
-    reveal_type(a in d)  # revealed: bool
-    reveal_type(a not in d)  # revealed: bool
+reveal_type(a in c)  # revealed: Literal[False]
+reveal_type(a not in c)  # revealed: Literal[True]
+
+reveal_type(a in d)  # revealed: bool
+reveal_type(a not in d)  # revealed: bool
 ```
 
 ### Identity Comparisons

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

@@ -5,46 +5,49 @@
 Comparisons on union types need to consider all possible cases:
 
 ```py
-def _(flag: bool):
-    one_or_two = 1 if flag else 2
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(one_or_two <= 2)  # revealed: Literal[True]
-    reveal_type(one_or_two <= 1)  # revealed: bool
-    reveal_type(one_or_two <= 0)  # revealed: Literal[False]
+flag = bool_instance()
+one_or_two = 1 if flag else 2
 
-    reveal_type(2 >= one_or_two)  # revealed: Literal[True]
-    reveal_type(1 >= one_or_two)  # revealed: bool
-    reveal_type(0 >= one_or_two)  # revealed: Literal[False]
+reveal_type(one_or_two <= 2)  # revealed: Literal[True]
+reveal_type(one_or_two <= 1)  # revealed: bool
+reveal_type(one_or_two <= 0)  # revealed: Literal[False]
 
-    reveal_type(one_or_two < 1)  # revealed: Literal[False]
-    reveal_type(one_or_two < 2)  # revealed: bool
-    reveal_type(one_or_two < 3)  # revealed: Literal[True]
+reveal_type(2 >= one_or_two)  # revealed: Literal[True]
+reveal_type(1 >= one_or_two)  # revealed: bool
+reveal_type(0 >= one_or_two)  # revealed: Literal[False]
 
-    reveal_type(one_or_two > 0)  # revealed: Literal[True]
-    reveal_type(one_or_two > 1)  # revealed: bool
-    reveal_type(one_or_two > 2)  # revealed: Literal[False]
+reveal_type(one_or_two < 1)  # revealed: Literal[False]
+reveal_type(one_or_two < 2)  # revealed: bool
+reveal_type(one_or_two < 3)  # revealed: Literal[True]
 
-    reveal_type(one_or_two == 3)  # revealed: Literal[False]
-    reveal_type(one_or_two == 1)  # revealed: bool
+reveal_type(one_or_two > 0)  # revealed: Literal[True]
+reveal_type(one_or_two > 1)  # revealed: bool
+reveal_type(one_or_two > 2)  # revealed: Literal[False]
 
-    reveal_type(one_or_two != 3)  # revealed: Literal[True]
-    reveal_type(one_or_two != 1)  # revealed: bool
+reveal_type(one_or_two == 3)  # revealed: Literal[False]
+reveal_type(one_or_two == 1)  # revealed: bool
 
-    a_or_ab = "a" if flag else "ab"
+reveal_type(one_or_two != 3)  # revealed: Literal[True]
+reveal_type(one_or_two != 1)  # revealed: bool
 
-    reveal_type(a_or_ab in "ab")  # revealed: Literal[True]
-    reveal_type("a" in a_or_ab)  # revealed: Literal[True]
+a_or_ab = "a" if flag else "ab"
 
-    reveal_type("c" not in a_or_ab)  # revealed: Literal[True]
-    reveal_type("a" not in a_or_ab)  # revealed: Literal[False]
+reveal_type(a_or_ab in "ab")  # revealed: Literal[True]
+reveal_type("a" in a_or_ab)  # revealed: Literal[True]
 
-    reveal_type("b" in a_or_ab)  # revealed: bool
-    reveal_type("b" not in a_or_ab)  # revealed: bool
+reveal_type("c" not in a_or_ab)  # revealed: Literal[True]
+reveal_type("a" not in a_or_ab)  # revealed: Literal[False]
 
-    one_or_none = 1 if flag else None
+reveal_type("b" in a_or_ab)  # revealed: bool
+reveal_type("b" not in a_or_ab)  # revealed: bool
 
-    reveal_type(one_or_none is None)  # revealed: bool
-    reveal_type(one_or_none is not None)  # revealed: bool
+one_or_none = 1 if flag else None
+
+reveal_type(one_or_none is None)  # revealed: bool
+reveal_type(one_or_none is not None)  # revealed: bool
 ```
 
 ## Union on both sides of the comparison
@@ -53,15 +56,18 @@ With unions on both sides, we need to consider the full cross product of options
 resulting (union) type:
 
 ```py
-def _(flag_s: bool, flag_l: bool):
-    small = 1 if flag_s else 2
-    large = 2 if flag_l else 3
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(small <= large)  # revealed: Literal[True]
-    reveal_type(small >= large)  # revealed: bool
+flag_s, flag_l = bool_instance(), bool_instance()
+small = 1 if flag_s else 2
+large = 2 if flag_l else 3
 
-    reveal_type(small < large)  # revealed: bool
-    reveal_type(small > large)  # revealed: Literal[False]
+reveal_type(small <= large)  # revealed: Literal[True]
+reveal_type(small >= large)  # revealed: bool
+
+reveal_type(small < large)  # revealed: bool
+reveal_type(small > large)  # revealed: Literal[False]
 ```
 
 ## Unsupported operations
@@ -71,9 +77,12 @@ back to `bool` for the result type instead of trying to infer something more pre
 (supported) variants:
 
 ```py
-def _(flag: bool):
-    x = [1, 2] if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    result = 1 in x  # error: "Operator `in` is not supported"
-    reveal_type(result)  # revealed: bool
+flag = bool_instance()
+x = [1, 2] if flag else 1
+
+result = 1 in x  # error: "Operator `in` is not supported"
+reveal_type(result)  # revealed: bool
 ```

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

@@ -1,38 +1,42 @@
 # Comparison: Unsupported operators
 
 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    class A: ...
-    a = 1 in 7  # error: "Operator `in` is not supported for types `Literal[1]` and `Literal[7]`"
-    reveal_type(a)  # revealed: bool
+def bool_instance() -> bool:
+    return True
 
-    b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
-    reveal_type(b)  # revealed: bool
+class A: ...
 
-    # TODO: should error, once operand type check is implemented
-    # ("Operator `<` is not supported for types `object` and `int`")
-    c = object() < 5
-    # TODO: should be Unknown, once operand type check is implemented
-    reveal_type(c)  # revealed: bool
+a = 1 in 7  # error: "Operator `in` is not supported for types `Literal[1]` and `Literal[7]`"
+reveal_type(a)  # revealed: bool
 
-    # TODO: should error, once operand type check is implemented
-    # ("Operator `<` is not supported for types `int` and `object`")
-    d = 5 < object()
-    # TODO: should be Unknown, once operand type check is implemented
-    reveal_type(d)  # revealed: bool
+b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
+reveal_type(b)  # revealed: bool
 
-    int_literal_or_str_literal = 1 if flag else "foo"
-    # error: "Operator `in` is not supported for types `Literal[42]` and `Literal[1]`, in comparing `Literal[42]` with `Literal[1] | Literal["foo"]`"
-    e = 42 in int_literal_or_str_literal
-    reveal_type(e)  # revealed: bool
+# TODO: should error, once operand type check is implemented
+# ("Operator `<` is not supported for types `object` and `int`")
+c = object() < 5
+# TODO: should be Unknown, once operand type check is implemented
+reveal_type(c)  # revealed: bool
 
-    # TODO: should error, need to check if __lt__ signature is valid for right operand
-    # error may be "Operator `<` is not supported for types `int` and `str`, in comparing `tuple[Literal[1], Literal[2]]` with `tuple[Literal[1], Literal["hello"]]`
-    f = (1, 2) < (1, "hello")
-    # TODO: should be Unknown, once operand type check is implemented
-    reveal_type(f)  # revealed: bool
+# TODO: should error, once operand type check is implemented
+# ("Operator `<` is not supported for types `int` and `object`")
+d = 5 < object()
+# TODO: should be Unknown, once operand type check is implemented
+reveal_type(d)  # revealed: bool
 
-    # error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[bool, A]` with `tuple[bool, A]`"
-    g = (flag1, A()) < (flag2, A())
-    reveal_type(g)  # revealed: Unknown
+flag = bool_instance()
+int_literal_or_str_literal = 1 if flag else "foo"
+# error: "Operator `in` is not supported for types `Literal[42]` and `Literal[1]`, in comparing `Literal[42]` with `Literal[1] | Literal["foo"]`"
+e = 42 in int_literal_or_str_literal
+reveal_type(e)  # revealed: bool
+
+# TODO: should error, need to check if __lt__ signature is valid for right operand
+# error may be "Operator `<` is not supported for types `int` and `str`, in comparing `tuple[Literal[1], Literal[2]]` with `tuple[Literal[1], Literal["hello"]]`
+f = (1, 2) < (1, "hello")
+# TODO: should be Unknown, once operand type check is implemented
+reveal_type(f)  # revealed: bool
+
+# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `A`, in comparing `tuple[bool, A]` with `tuple[bool, A]`"
+g = (bool_instance(), A()) < (bool_instance(), A())
+reveal_type(g)  # revealed: Unknown
 ```

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

@@ -3,35 +3,47 @@
 ## Simple if-expression
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else 2
-    reveal_type(x)  # revealed: Literal[1, 2]
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+x = 1 if flag else 2
+reveal_type(x)  # revealed: Literal[1, 2]
 ```
 
 ## If-expression with walrus operator
 
 ```py
-def _(flag: bool):
-    y = 0
-    z = 0
-    x = (y := 1) if flag else (z := 2)
-    reveal_type(x)  # revealed: Literal[1, 2]
-    reveal_type(y)  # revealed: Literal[0, 1]
-    reveal_type(z)  # revealed: Literal[0, 2]
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+y = 0
+z = 0
+x = (y := 1) if flag else (z := 2)
+reveal_type(x)  # revealed: Literal[1, 2]
+reveal_type(y)  # revealed: Literal[0, 1]
+reveal_type(z)  # revealed: Literal[0, 2]
 ```
 
 ## Nested if-expression
 
 ```py
-def _(flag: bool, flag2: bool):
-    x = 1 if flag else 2 if flag2 else 3
-    reveal_type(x)  # revealed: Literal[1, 2, 3]
+def bool_instance() -> bool:
+    return True
+
+flag, flag2 = bool_instance(), bool_instance()
+x = 1 if flag else 2 if flag2 else 3
+reveal_type(x)  # revealed: Literal[1, 2, 3]
 ```
 
 ## None
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else None
-    reveal_type(x)  # revealed: Literal[1] | None
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+x = 1 if flag else None
+reveal_type(x)  # revealed: Literal[1] | None
 ```

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

@@ -3,115 +3,128 @@
 ## Simple if
 
 ```py
-def _(flag: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        y = 3
+flag = bool_instance()
+y = 1
+y = 2
 
-    reveal_type(y)  # revealed: Literal[2, 3]
+if flag:
+    y = 3
+
+reveal_type(y)  # revealed: Literal[2, 3]
 ```
 
 ## Simple if-elif-else
 
 ```py
-def _(flag: bool, flag2: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        y = 3
-    elif flag2:
-        y = 4
-    else:
-        r = y
-        y = 5
-        s = y
-    x = y
+flag, flag2 = bool_instance(), bool_instance()
+y = 1
+y = 2
+if flag:
+    y = 3
+elif flag2:
+    y = 4
+else:
+    r = y
+    y = 5
+    s = y
+x = y
 
-    reveal_type(x)  # revealed: Literal[3, 4, 5]
+reveal_type(x)  # revealed: Literal[3, 4, 5]
 
-    # revealed: Literal[2]
-    # error: [possibly-unresolved-reference]
-    reveal_type(r)
+# revealed: Literal[2]
+# error: [possibly-unresolved-reference]
+reveal_type(r)
 
-    # revealed: Literal[5]
-    # error: [possibly-unresolved-reference]
-    reveal_type(s)
+# revealed: Literal[5]
+# error: [possibly-unresolved-reference]
+reveal_type(s)
 ```
 
 ## Single symbol across if-elif-else
 
 ```py
-def _(flag: bool, flag2: bool):
-    if flag:
-        y = 1
-    elif flag2:
-        y = 2
-    else:
-        y = 3
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(y)  # revealed: Literal[1, 2, 3]
+flag, flag2 = bool_instance(), bool_instance()
+
+if flag:
+    y = 1
+elif flag2:
+    y = 2
+else:
+    y = 3
+reveal_type(y)  # revealed: Literal[1, 2, 3]
 ```
 
 ## if-elif-else without else assignment
 
 ```py
-def _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        y = 1
-    elif flag2:
-        y = 2
-    else:
-        pass
-
-    reveal_type(y)  # revealed: Literal[0, 1, 2]
+flag, flag2 = bool_instance(), bool_instance()
+y = 0
+if flag:
+    y = 1
+elif flag2:
+    y = 2
+else:
+    pass
+reveal_type(y)  # revealed: Literal[0, 1, 2]
 ```
 
 ## if-elif-else with intervening assignment
 
 ```py
-def _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        y = 1
-        z = 3
-    elif flag2:
-        y = 2
-    else:
-        pass
-
-    reveal_type(y)  # revealed: Literal[0, 1, 2]
+flag, flag2 = bool_instance(), bool_instance()
+y = 0
+if flag:
+    y = 1
+    z = 3
+elif flag2:
+    y = 2
+else:
+    pass
+reveal_type(y)  # revealed: Literal[0, 1, 2]
 ```
 
 ## Nested if statement
 
 ```py
-def _(flag: bool, flag2: bool):
-    y = 0
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        if flag2:
-            y = 1
-
-    reveal_type(y)  # revealed: Literal[0, 1]
+flag, flag2 = bool_instance(), bool_instance()
+y = 0
+if flag:
+    if flag2:
+        y = 1
+reveal_type(y)  # revealed: Literal[0, 1]
 ```
 
 ## if-elif without else
 
 ```py
-def _(flag: bool, flag2: bool):
-    y = 1
-    y = 2
+def bool_instance() -> bool:
+    return True
 
-    if flag:
-        y = 3
-    elif flag2:
-        y = 4
+flag, flag2 = bool_instance(), bool_instance()
+y = 1
+y = 2
+if flag:
+    y = 3
+elif flag2:
+    y = 4
 
-    reveal_type(y)  # revealed: Literal[2, 3, 4]
+reveal_type(y)  # revealed: Literal[2, 3, 4]
 ```

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

@@ -3,43 +3,39 @@
 ## With wildcard
 
 ```py
-def _(target: int):
-    match target:
-        case 1:
-            y = 2
-        case _:
-            y = 3
+match 0:
+    case 1:
+        y = 2
+    case _:
+        y = 3
 
-    reveal_type(y)  # revealed: Literal[2, 3]
+reveal_type(y)  # revealed: Literal[2, 3]
 ```
 
 ## Without wildcard
 
 ```py
-def _(target: int):
-    match target:
-        case 1:
-            y = 2
-        case 2:
-            y = 3
+match 0:
+    case 1:
+        y = 2
+    case 2:
+        y = 3
 
-    # revealed: Literal[2, 3]
-    # error: [possibly-unresolved-reference]
-    reveal_type(y)
+# revealed: Literal[2, 3]
+# error: [possibly-unresolved-reference]
+reveal_type(y)
 ```
 
 ## Basic match
 
 ```py
-def _(target: int):
-    y = 1
-    y = 2
+y = 1
+y = 2
+match 0:
+    case 1:
+        y = 3
+    case 2:
+        y = 4
 
-    match target:
-        case 1:
-            y = 3
-        case 2:
-            y = 4
-
-    reveal_type(y)  # revealed: Literal[2, 3, 4]
+reveal_type(y)  # revealed: Literal[2, 3, 4]
 ```

crates/red_knot_python_semantic/resources/mdtest/declaration/error.md

@@ -10,35 +10,42 @@ x: str  # error: [invalid-declaration] "Cannot declare type `str` for inferred t
 ## Incompatible declarations
 
 ```py
-def _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True
 
-    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
+flag = bool_instance()
+if flag:
+    x: str
+else:
+    x: int
+x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: str, int"
 ```
 
 ## Partial declarations
 
 ```py
-def _(flag: bool):
-    if flag:
-        x: int
+def bool_instance() -> bool:
+    return True
 
-    x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: Unknown, int"
+flag = bool_instance()
+if flag:
+    x: int
+x = 1  # error: [conflicting-declarations] "Conflicting declared types for `x`: Unknown, int"
 ```
 
 ## Incompatible declarations with bad assignment
 
 ```py
-def _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True
 
-    # error: [conflicting-declarations]
-    # error: [invalid-assignment]
-    x = b"foo"
+flag = bool_instance()
+if flag:
+    x: str
+else:
+    x: int
+
+# error: [conflicting-declarations]
+# error: [invalid-assignment]
+x = b"foo"
 ```

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

@@ -49,44 +49,12 @@ def foo(
     try:
         help()
     except x as e:
-        reveal_type(e)  # revealed: AttributeError
+        # TODO: should be `AttributeError`
+        reveal_type(e)  # revealed: @Todo(exception type)
     except y as f:
-        reveal_type(f)  # revealed: OSError | RuntimeError
+        # TODO: should be `OSError | RuntimeError`
+        reveal_type(f)  # revealed: @Todo(exception type)
     except z as g:
         # TODO: should be `BaseException`
-        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
-```
-
-## Invalid exception handlers
-
-```py
-try:
-    pass
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal[3]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-except 3 as e:
-    reveal_type(e)  # revealed: Unknown
-
-try:
-    pass
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal["foo"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-# error: [invalid-exception-caught] "Cannot catch object of type `Literal[b"bar"]` in an exception handler (must be a `BaseException` subclass or a tuple of `BaseException` subclasses)"
-except (ValueError, OSError, "foo", b"bar") as e:
-    reveal_type(e)  # revealed: ValueError | OSError | Unknown
-
-def foo(
-    x: type[str],
-    y: tuple[type[OSError], type[RuntimeError], int],
-    z: tuple[type[str], ...],
-):
-    try:
-        help()
-    # error: [invalid-exception-caught]
-    except x as e:
-        reveal_type(e)  # revealed: Unknown
-    # error: [invalid-exception-caught]
-    except y as f:
-        reveal_type(f)  # revealed: OSError | RuntimeError | Unknown
-    except z as g:
-        # TODO: should emit a diagnostic here:
-        reveal_type(g)  # revealed: @Todo(full tuple[...] support)
+        reveal_type(g)  # revealed: @Todo(exception type)
 ```

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

@@ -1,66 +1,30 @@
-# `except*`
+# Except star
 
-`except*` is only available in Python 3.11 and later:
-
-```toml
-[environment]
-python-version = "3.11"
-```
-
-## `except*` with `BaseException`
+## Except\* with BaseException
 
 ```py
 try:
     help()
 except* BaseException as e:
-    # TODO: should be `BaseExceptionGroup[BaseException]` --Alex
     reveal_type(e)  # revealed: BaseExceptionGroup
 ```
 
-## `except*` with specific exception
+## Except\* with specific exception
 
 ```py
 try:
     help()
 except* OSError as e:
-    # TODO: more precise would be `ExceptionGroup[OSError]` --Alex
-    # (needs homogenous tuples + generics)
+    # TODO(Alex): more precise would be `ExceptionGroup[OSError]`
     reveal_type(e)  # revealed: BaseExceptionGroup
 ```
 
-## `except*` with multiple exceptions
+## Except\* with multiple exceptions
 
 ```py
 try:
     help()
 except* (TypeError, AttributeError) as e:
-    # TODO: more precise would be `ExceptionGroup[TypeError | AttributeError]` --Alex
-    # (needs homogenous tuples + generics)
-    reveal_type(e)  # revealed: BaseExceptionGroup
-```
-
-## `except*` with mix of `Exception`s and `BaseException`s
-
-```py
-try:
-    help()
-except* (KeyboardInterrupt, AttributeError) as e:
-    # TODO: more precise would be `BaseExceptionGroup[KeyboardInterrupt | AttributeError]` --Alex
-    reveal_type(e)  # revealed: BaseExceptionGroup
-```
-
-## Invalid `except*` handlers
-
-```py
-try:
-    help()
-except* 3 as e:  # error: [invalid-exception-caught]
-    # TODO: Should be `BaseExceptionGroup[Unknown]` --Alex
-    reveal_type(e)  # revealed: BaseExceptionGroup
-
-try:
-    help()
-except* (AttributeError, 42) as e:  # error: [invalid-exception-caught]
-    # TODO: Should be `BaseExceptionGroup[AttributeError | Unknown]` --Alex
+    # TODO(Alex): more precise would be `ExceptionGroup[TypeError | AttributeError]`.
     reveal_type(e)  # revealed: BaseExceptionGroup
 ```

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

@@ -9,4 +9,5 @@ try:
     print
 except as e:  # error: [invalid-syntax]
     reveal_type(e)  # revealed: Unknown
+
 ```

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

@@ -3,25 +3,26 @@
 ## Boundness
 
 ```py
-def _(flag: bool):
-    class A:
-        always_bound = 1
+def flag() -> bool: ...
 
-        if flag:
-            union = 1
-        else:
-            union = "abc"
+class A:
+    always_bound = 1
 
-        if flag:
-            possibly_unbound = "abc"
+    if flag():
+        union = 1
+    else:
+        union = "abc"
 
-    reveal_type(A.always_bound)  # revealed: Literal[1]
+    if flag():
+        possibly_unbound = "abc"
 
-    reveal_type(A.union)  # revealed: Literal[1] | Literal["abc"]
+reveal_type(A.always_bound)  # revealed: Literal[1]
 
-    # error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
-    reveal_type(A.possibly_unbound)  # revealed: Literal["abc"]
+reveal_type(A.union)  # revealed: Literal[1] | Literal["abc"]
 
-    # error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
-    reveal_type(A.non_existent)  # revealed: Unknown
+# error: [possibly-unbound-attribute] "Attribute `possibly_unbound` on type `Literal[A]` is possibly unbound"
+reveal_type(A.possibly_unbound)  # revealed: Literal["abc"]
+
+# error: [unresolved-attribute] "Type `Literal[A]` has no attribute `non_existent`"
+reveal_type(A.non_existent)  # revealed: Unknown
 ```

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

@@ -3,45 +3,54 @@
 ## OR
 
 ```py
-def _(foo: str):
-    reveal_type(True or False)  # revealed: Literal[True]
-    reveal_type("x" or "y" or "z")  # revealed: Literal["x"]
-    reveal_type("" or "y" or "z")  # revealed: Literal["y"]
-    reveal_type(False or "z")  # revealed: Literal["z"]
-    reveal_type(False or True)  # revealed: Literal[True]
-    reveal_type(False or False)  # revealed: Literal[False]
-    reveal_type(foo or False)  # revealed: str | Literal[False]
-    reveal_type(foo or True)  # revealed: str | Literal[True]
+def foo() -> str:
+    pass
+
+reveal_type(True or False)  # revealed: Literal[True]
+reveal_type("x" or "y" or "z")  # revealed: Literal["x"]
+reveal_type("" or "y" or "z")  # revealed: Literal["y"]
+reveal_type(False or "z")  # revealed: Literal["z"]
+reveal_type(False or True)  # revealed: Literal[True]
+reveal_type(False or False)  # revealed: Literal[False]
+reveal_type(foo() or False)  # revealed: str | Literal[False]
+reveal_type(foo() or True)  # revealed: str | Literal[True]
 ```
 
 ## AND
 
 ```py
-def _(foo: str):
-    reveal_type(True and False)  # revealed: Literal[False]
-    reveal_type(False and True)  # revealed: Literal[False]
-    reveal_type(foo and False)  # revealed: str | Literal[False]
-    reveal_type(foo and True)  # revealed: str | Literal[True]
-    reveal_type("x" and "y" and "z")  # revealed: Literal["z"]
-    reveal_type("x" and "y" and "")  # revealed: Literal[""]
-    reveal_type("" and "y")  # revealed: Literal[""]
+def foo() -> str:
+    pass
+
+reveal_type(True and False)  # revealed: Literal[False]
+reveal_type(False and True)  # revealed: Literal[False]
+reveal_type(foo() and False)  # revealed: str | Literal[False]
+reveal_type(foo() and True)  # revealed: str | Literal[True]
+reveal_type("x" and "y" and "z")  # revealed: Literal["z"]
+reveal_type("x" and "y" and "")  # revealed: Literal[""]
+reveal_type("" and "y")  # revealed: Literal[""]
 ```
 
 ## Simple function calls to bool
 
 ```py
-def _(flag: bool):
-    if flag:
-        x = True
-    else:
-        x = False
+def returns_bool() -> bool:
+    return True
 
-    reveal_type(x)  # revealed: bool
+if returns_bool():
+    x = True
+else:
+    x = False
+
+reveal_type(x)  # revealed: bool
 ```
 
 ## Complex
 
 ```py
+def foo() -> str:
+    pass
+
 reveal_type("x" and "y" or "z")  # revealed: Literal["y"]
 reveal_type("x" or "y" and "z")  # revealed: Literal["x"]
 reveal_type("" and "y" or "z")  # revealed: Literal["z"]

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

@@ -3,8 +3,10 @@
 ## Union
 
 ```py
-def _(flag: bool):
-    reveal_type(1 if flag else 2)  # revealed: Literal[1, 2]
+def bool_instance() -> bool:
+    return True
+
+reveal_type(1 if bool_instance() else 2)  # revealed: Literal[1, 2]
 ```
 
 ## Statically known branches
@@ -28,12 +30,14 @@ reveal_type(1 if 0 else 2)  # revealed: Literal[2]
 The test inside an if expression should not affect code outside of the expression.
 
 ```py
-def _(flag: bool):
-    x: Literal[42, "hello"] = 42 if flag else "hello"
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+x: Literal[42, "hello"] = 42 if bool_instance() else "hello"
 
-    _ = ... if isinstance(x, str) else ...
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
 
-    reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
+_ = ... if isinstance(x, str) else ...
+
+reveal_type(x)  # revealed: Literal[42] | Literal["hello"]
 ```

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

@@ -211,7 +211,8 @@ reveal_type(len(SecondRequiredArgument()))  # revealed: Literal[1]
 ### No `__len__`
 
 ```py
-class NoDunderLen: ...
+class NoDunderLen:
+    pass
 
 # TODO: Emit a diagnostic
 reveal_type(len(NoDunderLen()))  # revealed: int

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

@@ -3,6 +3,6 @@
 ```py
 import builtins
 
-x = builtins.chr
-reveal_type(x)  # revealed: Literal[chr]
+x = builtins.copyright
+reveal_type(x)  # revealed: Literal[copyright]
 ```

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

@@ -3,10 +3,11 @@
 ## Maybe unbound
 
 ```py path=maybe_unbound.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+flag = bool_instance()
+if flag:
     y = 3
 
 x = y  # error: [possibly-unresolved-reference]
@@ -30,12 +31,13 @@ reveal_type(y)  # revealed: Literal[3]
 ## Maybe unbound annotated
 
 ```py path=maybe_unbound_annotated.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
-    y: int = 3
+flag = bool_instance()
 
+if flag:
+    y: int = 3
 x = y  # error: [possibly-unresolved-reference]
 
 # revealed: Literal[3]
@@ -61,10 +63,10 @@ reveal_type(y)  # revealed: int
 Importing a possibly undeclared name still gives us its declared type:
 
 ```py path=maybe_undeclared.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+if bool_instance():
     x: int
 ```
 
@@ -81,12 +83,14 @@ def f(): ...
 ```
 
 ```py path=b.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+flag = bool_instance()
+if flag:
     from c import f
 else:
+
     def f(): ...
 ```
 
@@ -107,10 +111,11 @@ x: int
 ```
 
 ```py path=b.py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+flag = bool_instance()
+if flag:
     from c import x
 else:
     x = 1

crates/red_knot_python_semantic/resources/mdtest/known_constants.md

@@ -1,52 +0,0 @@
-# Known constants
-
-## `typing.TYPE_CHECKING`
-
-This constant is `True` when in type-checking mode, `False` otherwise. The symbol is defined to be
-`False` at runtime. In typeshed, it is annotated as `bool`. This test makes sure that we infer
-`Literal[True]` for it anyways.
-
-### Basic
-
-```py
-from typing import TYPE_CHECKING
-import typing
-
-reveal_type(TYPE_CHECKING)  # revealed: Literal[True]
-reveal_type(typing.TYPE_CHECKING)  # revealed: Literal[True]
-```
-
-### Aliased
-
-Make sure that we still infer the correct type if the constant has been given a different name:
-
-```py
-from typing import TYPE_CHECKING as TC
-
-reveal_type(TC)  # revealed: Literal[True]
-```
-
-### Must originate from `typing`
-
-Make sure we only use our special handling for `typing.TYPE_CHECKING` and not for other constants
-with the same name:
-
-```py path=constants.py
-TYPE_CHECKING: bool = False
-```
-
-```py
-from constants import TYPE_CHECKING
-
-reveal_type(TYPE_CHECKING)  # revealed: bool
-```
-
-### `typing_extensions` re-export
-
-This should behave in the same way as `typing.TYPE_CHECKING`:
-
-```py
-from typing_extensions import TYPE_CHECKING
-
-reveal_type(TYPE_CHECKING)  # revealed: Literal[True]
-```

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

@@ -45,19 +45,19 @@ def f():
     # TODO: This should be Color.RED
     reveal_type(b1)  # revealed: Literal[0]
 
-# error: [invalid-type-form]
+# error: [invalid-literal-parameter]
 invalid1: Literal[3 + 4]
-# error: [invalid-type-form]
+# error: [invalid-literal-parameter]
 invalid2: Literal[4 + 3j]
-# error: [invalid-type-form]
+# error: [invalid-literal-parameter]
 invalid3: Literal[(3, 4)]
 
 hello = "hello"
 invalid4: Literal[
-    1 + 2,  # error: [invalid-type-form]
+    1 + 2,  # error: [invalid-literal-parameter]
     "foo",
-    hello,  # error: [invalid-type-form]
-    (1, 2, 3),  # error: [invalid-type-form]
+    hello,  # error: [invalid-literal-parameter]
+    (1, 2, 3),  # error: [invalid-literal-parameter]
 ]
 ```
 
@@ -91,13 +91,3 @@ a1: Literal[26]
 def f():
     reveal_type(a1)  # revealed: Literal[26]
 ```
-
-## Invalid
-
-```py
-from typing import Literal
-
-# error: [invalid-type-form] "`Literal` requires at least one argument when used in a type expression"
-def _(x: Literal):
-    reveal_type(x)  # revealed: Unknown
-```

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

@@ -106,19 +106,23 @@ reveal_type(x)
 ## With non-callable iterator
 
 ```py
-def _(flag: bool):
-    class NotIterable:
-        if flag:
-            __iter__ = 1
-        else:
-            __iter__ = None
+def bool_instance() -> bool:
+    return True
 
-    for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
-        pass
+flag = bool_instance()
 
-    # revealed: Unknown
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)
+class NotIterable:
+    if flag:
+        __iter__ = 1
+    else:
+        __iter__ = None
+
+for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
+    pass
+
+# revealed: Unknown
+# error: [possibly-unresolved-reference]
+reveal_type(x)
 ```
 
 ## Invalid iterable
@@ -156,9 +160,13 @@ class Test2:
     def __iter__(self) -> TestIter:
         return TestIter()
 
-def _(flag: bool):
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: int
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+for x in Test() if flag else Test2():
+    reveal_type(x)  # revealed: int
 ```
 
 ## Union type as iterator
@@ -207,9 +215,13 @@ class Test2:
     def __iter__(self) -> TestIter3 | TestIter4:
         return TestIter3()
 
-def _(flag: bool):
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: int | Exception | str | tuple[int, int] | bytes | memoryview
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+
+for x in Test() if flag else Test2():
+    reveal_type(x)  # revealed: int | Exception | str | tuple[int, int] | bytes | memoryview
 ```
 
 ## Union type as iterable where one union element has no `__iter__` method
@@ -223,10 +235,12 @@ class Test:
     def __iter__(self) -> TestIter:
         return TestIter()
 
-def _(flag: bool):
-    # error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
-    for x in Test() if flag else 42:
-        reveal_type(x)  # revealed: int
+def coinflip() -> bool:
+    return True
+
+# error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
+for x in Test() if coinflip() else 42:
+    reveal_type(x)  # revealed: int
 ```
 
 ## Union type as iterable where one union element has invalid `__iter__` method
@@ -244,10 +258,12 @@ class Test2:
     def __iter__(self) -> int:
         return 42
 
-def _(flag: bool):
-    # error: "Object of type `Test | Test2` is not iterable"
-    for x in Test() if flag else Test2():
-        reveal_type(x)  # revealed: Unknown
+def coinflip() -> bool:
+    return True
+
+# error: "Object of type `Test | Test2` is not iterable"
+for x in Test() if coinflip() else Test2():
+    reveal_type(x)  # revealed: Unknown
 ```
 
 ## Union type as iterator where one union element has no `__next__` method

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

@@ -1,50 +1,59 @@
 # While loops
 
-## Basic `while` loop
+## Basic While Loop
 
 ```py
-def _(flag: bool):
-    x = 1
-    while flag:
-        x = 2
+def bool_instance() -> bool:
+    return True
 
+flag = bool_instance()
+x = 1
+while flag:
+    x = 2
+
+reveal_type(x)  # revealed: Literal[1, 2]
+```
+
+## While with else (no break)
+
+```py
+def bool_instance() -> bool:
+    return True
+
+flag = bool_instance()
+x = 1
+while flag:
+    x = 2
+else:
     reveal_type(x)  # revealed: Literal[1, 2]
+    x = 3
+
+reveal_type(x)  # revealed: Literal[3]
 ```
 
-## `while` with `else` (no `break`)
+## While with Else (may break)
 
 ```py
-def _(flag: bool):
-    x = 1
-    while flag:
-        x = 2
-    else:
-        reveal_type(x)  # revealed: Literal[1, 2]
-        x = 3
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(x)  # revealed: Literal[3]
+flag, flag2 = bool_instance(), bool_instance()
+x = 1
+y = 0
+while flag:
+    x = 2
+    if flag2:
+        y = 4
+        break
+else:
+    y = x
+    x = 3
+
+reveal_type(x)  # revealed: Literal[2, 3]
+reveal_type(y)  # revealed: Literal[1, 2, 4]
 ```
 
-## `while` with `else` (may `break`)
-
-```py
-def _(flag: bool, flag2: bool):
-    x = 1
-    y = 0
-    while flag:
-        x = 2
-        if flag2:
-            y = 4
-            break
-    else:
-        y = x
-        x = 3
-
-    reveal_type(x)  # revealed: Literal[2, 3]
-    reveal_type(y)  # revealed: Literal[1, 2, 4]
-```
-
-## Nested `while` loops
+## Nested while loops
 
 ```py
 def flag() -> bool:
@@ -69,50 +78,3 @@ else:
 
 reveal_type(x)  # revealed: Literal[3, 4, 5]
 ```
-
-## Boundness
-
-Make sure that the boundness information is correctly tracked in `while` loop control flow.
-
-### Basic `while` loop
-
-```py
-def _(flag: bool):
-    while flag:
-        x = 1
-
-    # error: [possibly-unresolved-reference]
-    x
-```
-
-### `while` with `else` (no `break`)
-
-```py
-def _(flag: bool):
-    while flag:
-        y = 1
-    else:
-        x = 1
-
-    # no error, `x` is always bound
-    x
-    # error: [possibly-unresolved-reference]
-    y
-```
-
-### `while` with `else` (may `break`)
-
-```py
-def _(flag: bool, flag2: bool):
-    while flag:
-        x = 1
-        if flag2:
-            break
-    else:
-        y = 1
-
-    # error: [possibly-unresolved-reference]
-    x
-    # error: [possibly-unresolved-reference]
-    y
-```

crates/red_knot_python_semantic/resources/mdtest/mdtest_config.md

@@ -5,7 +5,7 @@ The following configuration will be attached to the *root* section (without any
 
 ```toml
 [environment]
-python-version = "3.10"
+target-version = "3.10"
 ```
 
 # Basic
@@ -34,7 +34,7 @@ Here, we make sure that we can overwrite the global configuration in a child sec
 
 ```toml
 [environment]
-python-version = "3.11"
+target-version = "3.11"
 ```
 
 ```py
@@ -55,7 +55,7 @@ Children in this section should all use the section configuration:
 
 ```toml
 [environment]
-python-version = "3.12"
+target-version = "3.12"
 ```
 
 ## Child

crates/red_knot_python_semantic/resources/mdtest/metaclass.md

@@ -68,7 +68,7 @@ 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: type[Unknown]
+reveal_type(C.__class__)  # revealed: Unknown
 ```
 
 ## Conflict (2)
@@ -85,7 +85,7 @@ 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: type[Unknown]
+reveal_type(B.__class__)  # revealed: Unknown
 ```
 
 ## Common metaclass
@@ -129,7 +129,7 @@ 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: type[Unknown]
+reveal_type(D.__class__)  # revealed: Unknown
 ```
 
 ## Unknown
@@ -183,7 +183,7 @@ class A(B): ...  # error: [cyclic-class-definition]
 class B(C): ...  # error: [cyclic-class-definition]
 class C(A): ...  # error: [cyclic-class-definition]
 
-reveal_type(A.__class__)  # revealed: type[Unknown]
+reveal_type(A.__class__)  # revealed: Unknown
 ```
 
 ## PEP 695 generic
@@ -194,26 +194,3 @@ class A[T: str](metaclass=M): ...
 
 reveal_type(A.__class__)  # revealed: Literal[M]
 ```
-
-## Metaclasses of metaclasses
-
-```py
-class Foo(type): ...
-class Bar(type, metaclass=Foo): ...
-class Baz(type, metaclass=Bar): ...
-class Spam(metaclass=Baz): ...
-
-reveal_type(Spam.__class__)  # revealed: Literal[Baz]
-reveal_type(Spam.__class__.__class__)  # revealed: Literal[Bar]
-reveal_type(Spam.__class__.__class__.__class__)  # revealed: Literal[Foo]
-
-def test(x: Spam):
-    reveal_type(x.__class__)  # revealed: type[Spam]
-    reveal_type(x.__class__.__class__)  # revealed: type[Baz]
-    reveal_type(x.__class__.__class__.__class__)  # revealed: type[Bar]
-    reveal_type(x.__class__.__class__.__class__.__class__)  # revealed: type[Foo]
-    reveal_type(x.__class__.__class__.__class__.__class__.__class__)  # revealed: type[type]
-
-    # revealed: type[type]
-    reveal_type(x.__class__.__class__.__class__.__class__.__class__.__class__.__class__.__class__)
-```

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

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

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

@@ -9,67 +9,85 @@ Similarly, in `and` expressions, the right-hand side is evaluated only if the le
 ## Narrowing in `or`
 
 ```py
-def _(flag: bool):
-    class A: ...
-    x: A | None = A() if flag else None
+def bool_instance() -> bool:
+    return True
 
-    isinstance(x, A) or reveal_type(x)  # revealed: None
-    x is None or reveal_type(x)  # revealed: A
-    reveal_type(x)  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+isinstance(x, A) or reveal_type(x)  # revealed: None
+x is None or reveal_type(x)  # revealed: A
+reveal_type(x)  # revealed: A | None
 ```
 
 ## Narrowing in `and`
 
 ```py
-def _(flag: bool):
-    class A: ...
-    x: A | None = A() if flag else None
+def bool_instance() -> bool:
+    return True
 
-    isinstance(x, A) and reveal_type(x)  # revealed: A
-    x is None and reveal_type(x)  # revealed: None
-    reveal_type(x)  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+isinstance(x, A) and reveal_type(x)  # revealed: A
+x is None and reveal_type(x)  # revealed: None
+reveal_type(x)  # revealed: A | None
 ```
 
 ## Multiple `and` arms
 
 ```py
-def _(flag1: bool, flag2: bool, flag3: bool, flag4: bool):
-    class A: ...
-    x: A | None = A() if flag1 else None
+def bool_instance() -> bool:
+    return True
 
-    flag2 and isinstance(x, A) and reveal_type(x)  # revealed: A
-    isinstance(x, A) and flag2 and reveal_type(x)  # revealed: A
-    reveal_type(x) and isinstance(x, A) and flag3  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+bool_instance() and isinstance(x, A) and reveal_type(x)  # revealed: A
+isinstance(x, A) and bool_instance() and reveal_type(x)  # revealed: A
+reveal_type(x) and isinstance(x, A) and bool_instance()  # revealed: A | None
 ```
 
 ## Multiple `or` arms
 
 ```py
-def _(flag1: bool, flag2: bool, flag3: bool, flag4: bool):
-    class A: ...
-    x: A | None = A() if flag1 else None
+def bool_instance() -> bool:
+    return True
 
-    flag2 or isinstance(x, A) or reveal_type(x)  # revealed: None
-    isinstance(x, A) or flag3 or reveal_type(x)  # revealed: None
-    reveal_type(x) or isinstance(x, A) or flag4  # revealed: A | None
+class A: ...
+
+x: A | None = A() if bool_instance() else None
+
+bool_instance() or isinstance(x, A) or reveal_type(x)  # revealed: None
+isinstance(x, A) or bool_instance() or reveal_type(x)  # revealed: None
+reveal_type(x) or isinstance(x, A) or bool_instance()  # revealed: A | None
 ```
 
 ## Multiple predicates
 
 ```py
-def _(flag1: bool, flag2: bool):
-    class A: ...
-    x: A | None | Literal[1] = A() if flag1 else None if flag2 else 1
+def bool_instance() -> bool:
+    return True
 
-    x is None or isinstance(x, A) or reveal_type(x)  # revealed: Literal[1]
+class A: ...
+
+x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
+
+x is None or isinstance(x, A) or reveal_type(x)  # revealed: Literal[1]
 ```
 
 ## Mix of `and` and `or`
 
 ```py
-def _(flag1: bool, flag2: bool):
-    class A: ...
-    x: A | None | Literal[1] = A() if flag1 else None if flag2 else 1
+def bool_instance() -> bool:
+    return True
 
-    isinstance(x, A) or x is not None and reveal_type(x)  # revealed: Literal[1]
+class A: ...
+
+x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
+
+isinstance(x, A) or x is not None and reveal_type(x)  # revealed: Literal[1]
 ```

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

@@ -6,11 +6,15 @@
 class A: ...
 class B: ...
 
-def _(x: A | B):
-    if isinstance(x, A) and isinstance(x, B):
-        reveal_type(x)  # revealed:  A & B
-    else:
-        reveal_type(x)  # revealed:  B & ~A | A & ~B
+def instance() -> A | B:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) and isinstance(x, B):
+    reveal_type(x)  # revealed:  A & B
+else:
+    reveal_type(x)  # revealed:  B & ~A | A & ~B
 ```
 
 ## Arms might not add narrowing constraints
@@ -19,18 +23,25 @@ def _(x: A | B):
 class A: ...
 class B: ...
 
-def _(flag: bool, x: A | B):
-    if isinstance(x, A) and flag:
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+def bool_instance() -> bool:
+    return True
 
-    if flag and isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+def instance() -> A | B:
+    return A()
 
+x = instance()
+
+if isinstance(x, A) and bool_instance():
+    reveal_type(x)  # revealed: A
+else:
     reveal_type(x)  # revealed: A | B
+
+if bool_instance() and isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: A | B
+
+reveal_type(x)  # revealed: A | B
 ```
 
 ## Statically known arms
@@ -39,35 +50,39 @@ def _(flag: bool, x: A | B):
 class A: ...
 class B: ...
 
-def _(x: A | B):
-    if isinstance(x, A) and True:
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
+def instance() -> A | B:
+    return A()
 
-    if True and isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
+x = instance()
 
-    if False and isinstance(x, A):
-        # TODO: should emit an `unreachable code` diagnostic
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: A | B
+if isinstance(x, A) and True:
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A
 
-    if False or isinstance(x, A):
-        reveal_type(x)  # revealed: A
-    else:
-        reveal_type(x)  # revealed: B & ~A
-
-    if True or isinstance(x, A):
-        reveal_type(x)  # revealed: A | B
-    else:
-        # TODO: should emit an `unreachable code` diagnostic
-        reveal_type(x)  # revealed: B & ~A
+if True and isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A
 
+if False and isinstance(x, A):
+    # TODO: should emit an `unreachable code` diagnostic
+    reveal_type(x)  # revealed: A
+else:
     reveal_type(x)  # revealed: A | B
+
+if False or isinstance(x, A):
+    reveal_type(x)  # revealed: A
+else:
+    reveal_type(x)  # revealed: B & ~A
+
+if True or isinstance(x, A):
+    reveal_type(x)  # revealed: A | B
+else:
+    # TODO: should emit an `unreachable code` diagnostic
+    reveal_type(x)  # revealed: B & ~A
+
+reveal_type(x)  # revealed: A | B
 ```
 
 ## The type of multiple symbols can be narrowed down
@@ -76,17 +91,22 @@ def _(x: A | B):
 class A: ...
 class B: ...
 
-def _(x: A | B, y: A | B):
-    if isinstance(x, A) and isinstance(y, B):
-        reveal_type(x)  # revealed: A
-        reveal_type(y)  # revealed: B
-    else:
-        # No narrowing: Only-one or both checks might have failed
-        reveal_type(x)  # revealed: A | B
-        reveal_type(y)  # revealed: A | B
+def instance() -> A | B:
+    return A()
 
+x = instance()
+y = instance()
+
+if isinstance(x, A) and isinstance(y, B):
+    reveal_type(x)  # revealed: A
+    reveal_type(y)  # revealed: B
+else:
+    # No narrowing: Only-one or both checks might have failed
     reveal_type(x)  # revealed: A | B
     reveal_type(y)  # revealed: A | B
+
+reveal_type(x)  # revealed: A | B
+reveal_type(y)  # revealed: A | B
 ```
 
 ## Narrowing in `or` conditional
@@ -96,11 +116,15 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C):
-    if isinstance(x, A) or isinstance(x, B):
-        reveal_type(x)  # revealed:  A | B
-    else:
-        reveal_type(x)  # revealed:  C & ~A & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) or isinstance(x, B):
+    reveal_type(x)  # revealed:  A | B
+else:
+    reveal_type(x)  # revealed:  C & ~A & ~B
 ```
 
 ## In `or`, all arms should add constraint in order to narrow
@@ -110,11 +134,18 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(flag: bool, x: A | B | C):
-    if isinstance(x, A) or isinstance(x, B) or flag:
-        reveal_type(x)  # revealed:  A | B | C
-    else:
-        reveal_type(x)  # revealed:  C & ~A & ~B
+def instance() -> A | B | C:
+    return A()
+
+def bool_instance() -> bool:
+    return True
+
+x = instance()
+
+if isinstance(x, A) or isinstance(x, B) or bool_instance():
+    reveal_type(x)  # revealed:  A | B | C
+else:
+    reveal_type(x)  # revealed:  C & ~A & ~B
 ```
 
 ## in `or`, all arms should narrow the same set of symbols
@@ -124,23 +155,28 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C, y: A | B | C):
-    if isinstance(x, A) or isinstance(y, A):
-        # The predicate might be satisfied by the right side, so the type of `x` can’t be narrowed down here.
-        reveal_type(x)  # revealed:  A | B | C
-        # The same for `y`
-        reveal_type(y)  # revealed:  A | B | C
-    else:
-        reveal_type(x)  # revealed:  B & ~A | C & ~A
-        reveal_type(y)  # revealed:  B & ~A | C & ~A
+def instance() -> A | B | C:
+    return A()
 
-    if (isinstance(x, A) and isinstance(y, A)) or (isinstance(x, B) and isinstance(y, B)):
-        # Here, types of `x` and `y` can be narrowd since all `or` arms constraint them.
-        reveal_type(x)  # revealed:  A | B
-        reveal_type(y)  # revealed:  A | B
-    else:
-        reveal_type(x)  # revealed:  A | B | C
-        reveal_type(y)  # revealed:  A | B | C
+x = instance()
+y = instance()
+
+if isinstance(x, A) or isinstance(y, A):
+    # The predicate might be satisfied by the right side, so the type of `x` can’t be narrowed down here.
+    reveal_type(x)  # revealed:  A | B | C
+    # The same for `y`
+    reveal_type(y)  # revealed:  A | B | C
+else:
+    reveal_type(x)  # revealed:  B & ~A | C & ~A
+    reveal_type(y)  # revealed:  B & ~A | C & ~A
+
+if (isinstance(x, A) and isinstance(y, A)) or (isinstance(x, B) and isinstance(y, B)):
+    # Here, types of `x` and `y` can be narrowd since all `or` arms constraint them.
+    reveal_type(x)  # revealed:  A | B
+    reveal_type(y)  # revealed:  A | B
+else:
+    reveal_type(x)  # revealed:  A | B | C
+    reveal_type(y)  # revealed:  A | B | C
 ```
 
 ## mixing `and` and `not`
@@ -150,12 +186,16 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C):
-    if isinstance(x, B) and not isinstance(x, C):
-        reveal_type(x)  # revealed:  B & ~C
-    else:
-        # ~(B & ~C) -> ~B | C -> (A & ~B) | (C & ~B) | C -> (A & ~B) | C
-        reveal_type(x)  # revealed: A & ~B | C
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, B) and not isinstance(x, C):
+    reveal_type(x)  # revealed:  B & ~C
+else:
+    # ~(B & ~C) -> ~B | C -> (A & ~B) | (C & ~B) | C -> (A & ~B) | C
+    reveal_type(x)  # revealed: A & ~B | C
 ```
 
 ## mixing `or` and `not`
@@ -165,11 +205,15 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C):
-    if isinstance(x, B) or not isinstance(x, C):
-        reveal_type(x)  # revealed: B | A & ~C
-    else:
-        reveal_type(x)  # revealed: C & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, B) or not isinstance(x, C):
+    reveal_type(x)  # revealed: B | A & ~C
+else:
+    reveal_type(x)  # revealed: C & ~B
 ```
 
 ## `or` with nested `and`
@@ -179,12 +223,16 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C):
-    if isinstance(x, A) or (isinstance(x, B) and not isinstance(x, C)):
-        reveal_type(x)  # revealed:  A | B & ~C
-    else:
-        # ~(A | (B & ~C)) -> ~A & ~(B & ~C) -> ~A & (~B | C) -> (~A & C) | (~A ~ B)
-        reveal_type(x)  # revealed:  C & ~A
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) or (isinstance(x, B) and not isinstance(x, C)):
+    reveal_type(x)  # revealed:  A | B & ~C
+else:
+    # ~(A | (B & ~C)) -> ~A & ~(B & ~C) -> ~A & (~B | C) -> (~A & C) | (~A ~ B)
+    reveal_type(x)  # revealed:  C & ~A
 ```
 
 ## `and` with nested `or`
@@ -194,32 +242,41 @@ class A: ...
 class B: ...
 class C: ...
 
-def _(x: A | B | C):
-    if isinstance(x, A) and (isinstance(x, B) or not isinstance(x, C)):
-        # A & (B | ~C) -> (A & B) | (A & ~C)
-        reveal_type(x)  # revealed:  A & B | A & ~C
-    else:
-        # ~((A & B) | (A & ~C)) ->
-        # ~(A & B) & ~(A & ~C) ->
-        # (~A | ~B) & (~A | C) ->
-        # [(~A | ~B) & ~A] | [(~A | ~B) & C] ->
-        # ~A | (~A & C) | (~B & C) ->
-        # ~A | (C & ~B) ->
-        # ~A | (C & ~B)  The positive side of ~A is  A | B | C ->
-        reveal_type(x)  # revealed:  B & ~A | C & ~A | C & ~B
+def instance() -> A | B | C:
+    return A()
+
+x = instance()
+
+if isinstance(x, A) and (isinstance(x, B) or not isinstance(x, C)):
+    # A & (B | ~C) -> (A & B) | (A & ~C)
+    reveal_type(x)  # revealed:  A & B | A & ~C
+else:
+    # ~((A & B) | (A & ~C)) ->
+    # ~(A & B) & ~(A & ~C) ->
+    # (~A | ~B) & (~A | C) ->
+    # [(~A | ~B) & ~A] | [(~A | ~B) & C] ->
+    # ~A | (~A & C) | (~B & C) ->
+    # ~A | (C & ~B) ->
+    # ~A | (C & ~B)  The positive side of ~A is  A | B | C ->
+    reveal_type(x)  # revealed:  B & ~A | C & ~A | C & ~B
 ```
 
 ## Boolean expression internal narrowing
 
 ```py
-def _(x: str | None, y: str | None):
-    if x is None and y is not x:
-        reveal_type(y)  # revealed: str
+def optional_string() -> str | None:
+    return None
 
-    # Neither of the conditions alone is sufficient for narrowing y's type:
-    if x is None:
-        reveal_type(y)  # revealed: str | None
+x = optional_string()
+y = optional_string()
 
-    if y is not x:
-        reveal_type(y)  # revealed: str | None
+if x is None and y is not x:
+    reveal_type(y)  # revealed: str
+
+# Neither of the conditions alone is sufficient for narrowing y's type:
+if x is None:
+    reveal_type(y)  # revealed: str | None
+
+if y is not x:
+    reveal_type(y)  # revealed: str | None
 ```

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

@@ -3,47 +3,55 @@
 ## Positive contributions become negative in elif-else blocks
 
 ```py
-def _(x: int):
-    if x == 1:
-        # cannot narrow; could be a subclass of `int`
-        reveal_type(x)  # revealed: int
-    elif x == 2:
-        reveal_type(x)  # revealed: int & ~Literal[1]
-    elif x != 3:
-        reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
+def int_instance() -> int:
+    return 42
+
+x = int_instance()
+
+if x == 1:
+    # cannot narrow; could be a subclass of `int`
+    reveal_type(x)  # revealed: int
+elif x == 2:
+    reveal_type(x)  # revealed: int & ~Literal[1]
+elif x != 3:
+    reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
 ```
 
 ## Positive contributions become negative in elif-else blocks, with simplification
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True
 
-    if x == 1:
-        # TODO should be Literal[1]
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
-    elif x == 2:
-        # TODO should be Literal[2]
-        reveal_type(x)  # revealed: Literal[2, 3]
-    else:
-        reveal_type(x)  # revealed: Literal[3]
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x == 1:
+    # TODO should be Literal[1]
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
+elif x == 2:
+    # TODO should be Literal[2]
+    reveal_type(x)  # revealed: Literal[2, 3]
+else:
+    reveal_type(x)  # revealed: Literal[3]
 ```
 
 ## Multiple negative contributions using elif, with simplification
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True
 
-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2, 3]
-    elif x != 2:
-        # TODO should be `Literal[1]`
-        reveal_type(x)  # revealed: Literal[1, 3]
-    elif x == 3:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
-    else:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2]
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+elif x != 2:
+    # TODO should be `Literal[1]`
+    reveal_type(x)  # revealed: Literal[1, 3]
+elif x == 3:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
+else:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```

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

@@ -3,64 +3,77 @@
 ## `is None`
 
 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    if x is None:
-        reveal_type(x)  # revealed: None
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+flag = bool_instance()
+x = None if flag else 1
 
-    reveal_type(x)  # revealed: None | Literal[1]
+if x is None:
+    reveal_type(x)  # revealed: None
+else:
+    reveal_type(x)  # revealed: Literal[1]
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```
 
 ## `is` for other types
 
 ```py
-def _(flag: bool):
-    class A: ...
-    x = A()
-    y = x if flag else None
+def bool_instance() -> bool:
+    return True
 
-    if y is x:
-        reveal_type(y)  # revealed: A
-    else:
-        reveal_type(y)  # revealed: A | None
+flag = bool_instance()
 
+class A: ...
+
+x = A()
+y = x if flag else None
+
+if y is x:
+    reveal_type(y)  # revealed: A
+else:
     reveal_type(y)  # revealed: A | None
+
+reveal_type(y)  # revealed: A | None
 ```
 
 ## `is` in chained comparisons
 
 ```py
-def _(x_flag: bool, y_flag: bool):
-    x = True if x_flag else False
-    y = True if y_flag else False
+def bool_instance() -> bool:
+    return True
 
+x_flag, y_flag = bool_instance(), bool_instance()
+x = True if x_flag else False
+y = True if y_flag else False
+
+reveal_type(x)  # revealed: bool
+reveal_type(y)  # revealed: bool
+
+if y is x is False:  # Interpreted as `(y is x) and (x is False)`
+    reveal_type(x)  # revealed: Literal[False]
+    reveal_type(y)  # revealed: bool
+else:
+    # The negation of the clause above is (y is not x) or (x is not False)
+    # So we can't narrow the type of x or y here, because each arm of the `or` could be true
     reveal_type(x)  # revealed: bool
     reveal_type(y)  # revealed: bool
-
-    if y is x is False:  # Interpreted as `(y is x) and (x is False)`
-        reveal_type(x)  # revealed: Literal[False]
-        reveal_type(y)  # revealed: bool
-    else:
-        # The negation of the clause above is (y is not x) or (x is not False)
-        # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-        reveal_type(x)  # revealed: bool
-        reveal_type(y)  # revealed: bool
 ```
 
 ## `is` in elif clause
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = None if flag1 else (1 if flag2 else True)
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(x)  # revealed: None | Literal[1] | Literal[True]
-    if x is None:
-        reveal_type(x)  # revealed: None
-    elif x is True:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+x = None if bool_instance() else (1 if bool_instance() else True)
+
+reveal_type(x)  # revealed: None | Literal[1] | Literal[True]
+if x is None:
+    reveal_type(x)  # revealed: None
+elif x is True:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    reveal_type(x)  # revealed: Literal[1]
 ```

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

@@ -5,28 +5,34 @@
 The type guard removes `None` from the union type:
 
 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    if x is not None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: None
+flag = bool_instance()
+x = None if flag else 1
 
-    reveal_type(x)  # revealed: None | Literal[1]
+if x is not None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: None
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```
 
 ## `is not` for other singleton types
 
 ```py
-def _(flag: bool):
-    x = True if flag else False
-    reveal_type(x)  # revealed: bool
+def bool_instance() -> bool:
+    return True
 
-    if x is not False:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        reveal_type(x)  # revealed: Literal[False]
+flag = bool_instance()
+x = True if flag else False
+reveal_type(x)  # revealed: bool
+
+if x is not False:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    reveal_type(x)  # revealed: Literal[False]
 ```
 
 ## `is not` for non-singleton types
@@ -47,17 +53,20 @@ else:
 ## `is not` for other types
 
 ```py
-def _(flag: bool):
-    class A: ...
-    x = A()
-    y = x if flag else None
+def bool_instance() -> bool:
+    return True
 
-    if y is not x:
-        reveal_type(y)  # revealed: A | None
-    else:
-        reveal_type(y)  # revealed: A
+class A: ...
 
+x = A()
+y = x if bool_instance() else None
+
+if y is not x:
     reveal_type(y)  # revealed: A | None
+else:
+    reveal_type(y)  # revealed: A
+
+reveal_type(y)  # revealed: A | None
 ```
 
 ## `is not` in chained comparisons
@@ -65,20 +74,23 @@ def _(flag: bool):
 The type guard removes `False` from the union type of the tested value only.
 
 ```py
-def _(x_flag: bool, y_flag: bool):
-    x = True if x_flag else False
-    y = True if y_flag else False
+def bool_instance() -> bool:
+    return True
+
+x_flag, y_flag = bool_instance(), bool_instance()
+x = True if x_flag else False
+y = True if y_flag else False
+
+reveal_type(x)  # revealed: bool
+reveal_type(y)  # revealed: bool
+
+if y is not x is not False:  # Interpreted as `(y is not x) and (x is not False)`
+    reveal_type(x)  # revealed: Literal[True]
+    reveal_type(y)  # revealed: bool
+else:
+    # The negation of the clause above is (y is x) or (x is False)
+    # So we can't narrow the type of x or y here, because each arm of the `or` could be true
 
     reveal_type(x)  # revealed: bool
     reveal_type(y)  # revealed: bool
-
-    if y is not x is not False:  # Interpreted as `(y is not x) and (x is not False)`
-        reveal_type(x)  # revealed: Literal[True]
-        reveal_type(y)  # revealed: bool
-    else:
-        # The negation of the clause above is (y is x) or (x is False)
-        # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-
-        reveal_type(x)  # revealed: bool
-        reveal_type(y)  # revealed: bool
 ```

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

@@ -3,45 +3,54 @@
 ## Multiple negative contributions
 
 ```py
-def _(x: int):
-    if x != 1:
-        if x != 2:
-            if x != 3:
-                reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
+def int_instance() -> int:
+    return 42
+
+x = int_instance()
+
+if x != 1:
+    if x != 2:
+        if x != 3:
+            reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
 ```
 
 ## Multiple negative contributions with simplification
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True
 
-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2, 3]
-        if x != 2:
-            reveal_type(x)  # revealed: Literal[3]
+flag1, flag2 = bool_instance(), bool_instance()
+x = 1 if flag1 else 2 if flag2 else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+    if x != 2:
+        reveal_type(x)  # revealed: Literal[3]
 ```
 
 ## elif-else blocks
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True
 
-    if x != 1:
+x = 1 if bool_instance() else 2 if bool_instance() else 3
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+    if x == 2:
+        # TODO should be `Literal[2]`
         reveal_type(x)  # revealed: Literal[2, 3]
-        if x == 2:
-            # TODO should be `Literal[2]`
-            reveal_type(x)  # revealed: Literal[2, 3]
-        elif x == 3:
-            reveal_type(x)  # revealed: Literal[3]
-        else:
-            reveal_type(x)  # revealed: Never
-
-    elif x != 2:
-        # TODO should be Literal[1]
-        reveal_type(x)  # revealed: Literal[1, 3]
+    elif x == 3:
+        reveal_type(x)  # revealed: Literal[3]
     else:
-        # TODO should be Never
-        reveal_type(x)  # revealed: Literal[1, 2, 3]
+        reveal_type(x)  # revealed: Never
+
+elif x != 2:
+    # TODO should be Literal[1]
+    reveal_type(x)  # revealed: Literal[1, 3]
+else:
+    # TODO should be Never
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
 ```

crates/red_knot_python_semantic/resources/mdtest/narrow/conditionals/not.md

@@ -5,25 +5,29 @@ The `not` operator negates a constraint.
 ## `not is None`
 
 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    if not x is None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: None
+x = None if bool_instance() else 1
 
-    reveal_type(x)  # revealed: None | Literal[1]
+if not x is None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: None
+
+reveal_type(x)  # revealed: None | Literal[1]
 ```
 
 ## `not isinstance`
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    if not isinstance(x, (int)):
-        reveal_type(x)  # revealed: Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Literal[1]
+x = 1 if bool_instance() else "a"
+
+if not isinstance(x, (int)):
+    reveal_type(x)  # revealed: Literal["a"]
+else:
+    reveal_type(x)  # revealed: Literal[1]
 ```

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

@@ -3,66 +3,82 @@
 ## `x != None`
 
 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    if x != None:
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        # TODO should be None
-        reveal_type(x)  # revealed: None | Literal[1]
+flag = bool_instance()
+x = None if flag else 1
+
+if x != None:
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    # TODO should be None
+    reveal_type(x)  # revealed: None | Literal[1]
 ```
 
 ## `!=` for other singleton types
 
 ```py
-def _(flag: bool):
-    x = True if flag else False
+def bool_instance() -> bool:
+    return True
 
-    if x != False:
-        reveal_type(x)  # revealed: Literal[True]
-    else:
-        # TODO should be Literal[False]
-        reveal_type(x)  # revealed: bool
+flag = bool_instance()
+x = True if flag else False
+
+if x != False:
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    # TODO should be Literal[False]
+    reveal_type(x)  # revealed: bool
 ```
 
 ## `x != y` where `y` is of literal type
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else 2
+def bool_instance() -> bool:
+    return True
 
-    if x != 1:
-        reveal_type(x)  # revealed: Literal[2]
+flag = bool_instance()
+x = 1 if flag else 2
+
+if x != 1:
+    reveal_type(x)  # revealed: Literal[2]
 ```
 
 ## `x != y` where `y` is a single-valued type
 
 ```py
-def _(flag: bool):
-    class A: ...
-    class B: ...
-    C = A if flag else B
+def bool_instance() -> bool:
+    return True
 
-    if C != A:
-        reveal_type(C)  # revealed: Literal[B]
-    else:
-        # TODO should be Literal[A]
-        reveal_type(C)  # revealed: Literal[A, B]
+flag = bool_instance()
+
+class A: ...
+class B: ...
+
+C = A if flag else B
+
+if C != A:
+    reveal_type(C)  # revealed: Literal[B]
+else:
+    # TODO should be Literal[A]
+    reveal_type(C)  # revealed: Literal[A, B]
 ```
 
 ## `x != y` where `y` has multiple single-valued options
 
 ```py
-def _(flag1: bool, flag2: bool):
-    x = 1 if flag1 else 2
-    y = 2 if flag2 else 3
+def bool_instance() -> bool:
+    return True
 
-    if x != y:
-        reveal_type(x)  # revealed: Literal[1, 2]
-    else:
-        # TODO should be Literal[2]
-        reveal_type(x)  # revealed: Literal[1, 2]
+x = 1 if bool_instance() else 2
+y = 2 if bool_instance() else 3
+
+if x != y:
+    reveal_type(x)  # revealed: Literal[1, 2]
+else:
+    # TODO should be Literal[2]
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```
 
 ## `!=` for non-single-valued types
@@ -70,22 +86,34 @@ def _(flag1: bool, flag2: bool):
 Only single-valued types should narrow the type:
 
 ```py
-def _(flag: bool, a: int, y: int):
-    x = a if flag else None
+def bool_instance() -> bool:
+    return True
 
-    if x != y:
-        reveal_type(x)  # revealed: int | None
+def int_instance() -> int:
+    return 42
+
+flag = bool_instance()
+x = int_instance() if flag else None
+y = int_instance()
+
+if x != y:
+    reveal_type(x)  # revealed: int | None
 ```
 
 ## Mix of single-valued and non-single-valued types
 
 ```py
-def _(flag1: bool, flag2: bool, a: int):
-    x = 1 if flag1 else 2
-    y = 2 if flag2 else a
+def int_instance() -> int:
+    return 42
 
-    if x != y:
-        reveal_type(x)  # revealed: Literal[1, 2]
-    else:
-        reveal_type(x)  # revealed: Literal[1, 2]
+def bool_instance() -> bool:
+    return True
+
+x = 1 if bool_instance() else 2
+y = 2 if bool_instance() else int_instance()
+
+if x != y:
+    reveal_type(x)  # revealed: Literal[1, 2]
+else:
+    reveal_type(x)  # revealed: Literal[1, 2]
 ```

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

@@ -5,19 +5,23 @@ Narrowing for `isinstance(object, classinfo)` expressions.
 ## `classinfo` is a single type
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
+flag = bool_instance()
+
+x = 1 if flag else "a"
+
+if isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1]
+
+if isinstance(x, str):
+    reveal_type(x)  # revealed: Literal["a"]
     if isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+        reveal_type(x)  # revealed: Never
 
-    if isinstance(x, str):
-        reveal_type(x)  # revealed: Literal["a"]
-        if isinstance(x, int):
-            reveal_type(x)  # revealed: Never
-
-    if isinstance(x, (int, object)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+if isinstance(x, (int, object)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```
 
 ## `classinfo` is a tuple of types
@@ -26,48 +30,56 @@ Note: `isinstance(x, (int, str))` should not be confused with `isinstance(x, tup
 The former is equivalent to `isinstance(x, int | str)`:
 
 ```py
-def _(flag: bool, flag1: bool, flag2: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    if isinstance(x, (int, str)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Never
+flag, flag1, flag2 = bool_instance(), bool_instance(), bool_instance()
 
-    if isinstance(x, (int, bytes)):
-        reveal_type(x)  # revealed: Literal[1]
+x = 1 if flag else "a"
 
-    if isinstance(x, (bytes, str)):
-        reveal_type(x)  # revealed: Literal["a"]
+if isinstance(x, (int, str)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+else:
+    reveal_type(x)  # revealed: Never
 
-    # No narrowing should occur if a larger type is also
-    # one of the possibilities:
-    if isinstance(x, (int, object)):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-    else:
-        reveal_type(x)  # revealed: Never
+if isinstance(x, (int, bytes)):
+    reveal_type(x)  # revealed: Literal[1]
 
-    y = 1 if flag1 else "a" if flag2 else b"b"
-    if isinstance(y, (int, str)):
-        reveal_type(y)  # revealed: Literal[1] | Literal["a"]
+if isinstance(x, (bytes, str)):
+    reveal_type(x)  # revealed: Literal["a"]
 
-    if isinstance(y, (int, bytes)):
-        reveal_type(y)  # revealed: Literal[1] | Literal[b"b"]
+# No narrowing should occur if a larger type is also
+# one of the possibilities:
+if isinstance(x, (int, object)):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+else:
+    reveal_type(x)  # revealed: Never
 
-    if isinstance(y, (str, bytes)):
-        reveal_type(y)  # revealed: Literal["a"] | Literal[b"b"]
+y = 1 if flag1 else "a" if flag2 else b"b"
+if isinstance(y, (int, str)):
+    reveal_type(y)  # revealed: Literal[1] | Literal["a"]
+
+if isinstance(y, (int, bytes)):
+    reveal_type(y)  # revealed: Literal[1] | Literal[b"b"]
+
+if isinstance(y, (str, bytes)):
+    reveal_type(y)  # revealed: Literal["a"] | Literal[b"b"]
 ```
 
 ## `classinfo` is a nested tuple of types
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    if isinstance(x, (bool, (bytes, int))):
-        reveal_type(x)  # revealed: Literal[1]
-    else:
-        reveal_type(x)  # revealed: Literal["a"]
+flag = bool_instance()
+
+x = 1 if flag else "a"
+
+if isinstance(x, (bool, (bytes, int))):
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: Literal["a"]
 ```
 
 ## Class types
@@ -77,7 +89,9 @@ class A: ...
 class B: ...
 class C: ...
 
-x = object()
+def get_object() -> object: ...
+
+x = get_object()
 
 if isinstance(x, A):
     reveal_type(x)  # revealed: A
@@ -98,40 +112,50 @@ else:
 ## No narrowing for instances of `builtins.type`
 
 ```py
-def _(flag: bool):
-    t = type("t", (), {})
+def bool_instance() -> bool:
+    return True
 
-    # This isn't testing what we want it to test if we infer anything more precise here:
-    reveal_type(t)  # revealed: type
+flag = bool_instance()
 
-    x = 1 if flag else "foo"
+t = type("t", (), {})
 
-    if isinstance(x, t):
-        reveal_type(x)  # revealed: Literal[1] | Literal["foo"]
+# This isn't testing what we want it to test if we infer anything more precise here:
+reveal_type(t)  # revealed: type
+x = 1 if flag else "foo"
+
+if isinstance(x, t):
+    reveal_type(x)  # revealed: Literal[1] | Literal["foo"]
 ```
 
 ## Do not use custom `isinstance` for narrowing
 
 ```py
-def _(flag: bool):
-    def isinstance(x, t):
-        return True
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    if isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+
+def isinstance(x, t):
+    return True
+
+x = 1 if flag else "a"
+if isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```
 
 ## Do support narrowing if `isinstance` is aliased
 
 ```py
-def _(flag: bool):
-    isinstance_alias = isinstance
+def bool_instance() -> bool:
+    return True
 
-    x = 1 if flag else "a"
+flag = bool_instance()
 
-    if isinstance_alias(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+isinstance_alias = isinstance
+
+x = 1 if flag else "a"
+if isinstance_alias(x, int):
+    reveal_type(x)  # revealed: Literal[1]
 ```
 
 ## Do support narrowing if `isinstance` is imported
@@ -139,38 +163,46 @@ def _(flag: bool):
 ```py
 from builtins import isinstance as imported_isinstance
 
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    if imported_isinstance(x, int):
-        reveal_type(x)  # revealed: Literal[1]
+flag = bool_instance()
+x = 1 if flag else "a"
+if imported_isinstance(x, int):
+    reveal_type(x)  # revealed: Literal[1]
 ```
 
 ## Do not narrow if second argument is not a type
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    # TODO: this should cause us to emit a diagnostic during
-    # type checking
-    if isinstance(x, "a"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+x = 1 if flag else "a"
 
-    # TODO: this should cause us to emit a diagnostic during
-    # type checking
-    if isinstance(x, "int"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+# TODO: this should cause us to emit a diagnostic during
+# type checking
+if isinstance(x, "a"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+
+# TODO: this should cause us to emit a diagnostic during
+# type checking
+if isinstance(x, "int"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```
 
 ## Do not narrow if there are keyword arguments
 
 ```py
-def _(flag: bool):
-    x = 1 if flag else "a"
+def bool_instance() -> bool:
+    return True
 
-    # TODO: this should cause us to emit a diagnostic
-    # (`isinstance` has no `foo` parameter)
-    if isinstance(x, int, foo="bar"):
-        reveal_type(x)  # revealed: Literal[1] | Literal["a"]
+flag = bool_instance()
+x = 1 if flag else "a"
+
+# TODO: this should cause us to emit a diagnostic
+# (`isinstance` has no `foo` parameter)
+if isinstance(x, int, foo="bar"):
+    reveal_type(x)  # revealed: Literal[1] | Literal["a"]
 ```

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

@@ -7,43 +7,45 @@ Narrowing for `issubclass(class, classinfo)` expressions.
 ### Basic example
 
 ```py
-def _(flag: bool):
-    t = int if flag else str
+def flag() -> bool: ...
 
-    if issubclass(t, bytes):
-        reveal_type(t)  # revealed: Never
+t = int if flag() else str
 
-    if issubclass(t, object):
-        reveal_type(t)  # revealed: Literal[int, str]
+if issubclass(t, bytes):
+    reveal_type(t)  # revealed: Never
 
+if issubclass(t, object):
+    reveal_type(t)  # revealed: Literal[int, str]
+
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+else:
+    reveal_type(t)  # revealed: Literal[str]
+
+if issubclass(t, str):
+    reveal_type(t)  # revealed: Literal[str]
     if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    else:
-        reveal_type(t)  # revealed: Literal[str]
-
-    if issubclass(t, str):
-        reveal_type(t)  # revealed: Literal[str]
-        if issubclass(t, int):
-            reveal_type(t)  # revealed: Never
+        reveal_type(t)  # revealed: Never
 ```
 
 ### Proper narrowing in `elif` and `else` branches
 
 ```py
-def _(flag1: bool, flag2: bool):
-    t = int if flag1 else str if flag2 else bytes
+def flag() -> bool: ...
 
-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    else:
-        reveal_type(t)  # revealed: Literal[str, bytes]
+t = int if flag() else str if flag() else bytes
 
-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Literal[int]
-    elif issubclass(t, str):
-        reveal_type(t)  # revealed: Literal[str]
-    else:
-        reveal_type(t)  # revealed: Literal[bytes]
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+else:
+    reveal_type(t)  # revealed: Literal[str, bytes]
+
+if issubclass(t, int):
+    reveal_type(t)  # revealed: Literal[int]
+elif issubclass(t, str):
+    reveal_type(t)  # revealed: Literal[str]
+else:
+    reveal_type(t)  # revealed: Literal[bytes]
 ```
 
 ### Multiple derived classes
@@ -54,28 +56,29 @@ class Derived1(Base): ...
 class Derived2(Base): ...
 class Unrelated: ...
 
-def _(flag1: bool, flag2: bool, flag3: bool):
-    t1 = Derived1 if flag1 else Derived2
+def flag() -> bool: ...
 
-    if issubclass(t1, Base):
-        reveal_type(t1)  # revealed: Literal[Derived1, Derived2]
+t1 = Derived1 if flag() else Derived2
 
-    if issubclass(t1, Derived1):
-        reveal_type(t1)  # revealed: Literal[Derived1]
-    else:
-        reveal_type(t1)  # revealed: Literal[Derived2]
+if issubclass(t1, Base):
+    reveal_type(t1)  # revealed: Literal[Derived1, Derived2]
 
-    t2 = Derived1 if flag2 else Base
+if issubclass(t1, Derived1):
+    reveal_type(t1)  # revealed: Literal[Derived1]
+else:
+    reveal_type(t1)  # revealed: Literal[Derived2]
 
-    if issubclass(t2, Base):
-        reveal_type(t2)  # revealed: Literal[Derived1, Base]
+t2 = Derived1 if flag() else Base
 
-    t3 = Derived1 if flag3 else Unrelated
+if issubclass(t2, Base):
+    reveal_type(t2)  # revealed: Literal[Derived1, Base]
 
-    if issubclass(t3, Base):
-        reveal_type(t3)  # revealed: Literal[Derived1]
-    else:
-        reveal_type(t3)  # revealed: Literal[Unrelated]
+t3 = Derived1 if flag() else Unrelated
+
+if issubclass(t3, Base):
+    reveal_type(t3)  # revealed: Literal[Derived1]
+else:
+    reveal_type(t3)  # revealed: Literal[Unrelated]
 ```
 
 ### Narrowing for non-literals
@@ -84,13 +87,16 @@ def _(flag1: bool, flag2: bool, flag3: bool):
 class A: ...
 class B: ...
 
-def _(t: type[object]):
-    if issubclass(t, A):
-        reveal_type(t)  # revealed: type[A]
-        if issubclass(t, B):
-            reveal_type(t)  # revealed: type[A] & type[B]
-    else:
-        reveal_type(t)  # revealed: type[object] & ~type[A]
+def get_class() -> type[object]: ...
+
+t = get_class()
+
+if issubclass(t, A):
+    reveal_type(t)  # revealed: type[A]
+    if issubclass(t, B):
+        reveal_type(t)  # revealed: type[A] & type[B]
+else:
+    reveal_type(t)  # revealed: type[object] & ~type[A]
 ```
 
 ### Handling of `None`
@@ -101,15 +107,16 @@ def _(t: type[object]):
 # error: [possibly-unbound-import] "Member `NoneType` of module `types` is possibly unbound"
 from types import NoneType
 
-def _(flag: bool):
-    t = int if flag else NoneType
+def flag() -> bool: ...
 
-    if issubclass(t, NoneType):
-        reveal_type(t)  # revealed: Literal[NoneType]
+t = int if flag() else NoneType
 
-    if issubclass(t, type(None)):
-        # TODO: this should be just `Literal[NoneType]`
-        reveal_type(t)  # revealed: Literal[int, NoneType]
+if issubclass(t, NoneType):
+    reveal_type(t)  # revealed: Literal[NoneType]
+
+if issubclass(t, type(None)):
+    # TODO: this should be just `Literal[NoneType]`
+    reveal_type(t)  # revealed: Literal[int, NoneType]
 ```
 
 ## `classinfo` contains multiple types
@@ -119,13 +126,14 @@ def _(flag: bool):
 ```py
 class Unrelated: ...
 
-def _(flag1: bool, flag2: bool):
-    t = int if flag1 else str if flag2 else bytes
+def flag() -> bool: ...
 
-    if issubclass(t, (int, (Unrelated, (bytes,)))):
-        reveal_type(t)  # revealed: Literal[int, bytes]
-    else:
-        reveal_type(t)  # revealed: Literal[str]
+t = int if flag() else str if flag() else bytes
+
+if issubclass(t, (int, (Unrelated, (bytes,)))):
+    reveal_type(t)  # revealed: Literal[int, bytes]
+else:
+    reveal_type(t)  # revealed: Literal[str]
 ```
 
 ## Special cases
@@ -140,7 +148,9 @@ to `issubclass`:
 ```py
 class A: ...
 
-t = object()
+def get_object() -> object: ...
+
+t = get_object()
 
 # TODO: we should emit a diagnostic here
 if issubclass(t, A):

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

@@ -3,16 +3,19 @@
 ## Single `match` pattern
 
 ```py
-def _(flag: bool):
-    x = None if flag else 1
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(x)  # revealed: None | Literal[1]
+flag = bool_instance()
 
-    y = 0
+x = None if flag else 1
+reveal_type(x)  # revealed: None | Literal[1]
 
-    match x:
-        case None:
-            y = x
+y = 0
 
-    reveal_type(y)  # revealed: Literal[0] | None
+match x:
+    case None:
+        y = x
+
+reveal_type(y)  # revealed: Literal[0] | None
 ```

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

@@ -3,49 +3,62 @@
 ## After if-else statements, narrowing has no effect if the variable is not mutated in any branch
 
 ```py
-def _(x: int | None):
-    if x is None:
-        pass
-    else:
-        pass
+def optional_int() -> int | None: ...
 
-    reveal_type(x)  # revealed: int | None
+x = optional_int()
+
+if x is None:
+    pass
+else:
+    pass
+
+reveal_type(x)  # revealed: int | None
 ```
 
 ## Narrowing can have a persistent effect if the variable is mutated in one branch
 
 ```py
-def _(x: int | None):
-    if x is None:
-        x = 10
-    else:
-        pass
+def optional_int() -> int | None: ...
 
-    reveal_type(x)  # revealed: int
+x = optional_int()
+
+if x is None:
+    x = 10
+else:
+    pass
+
+reveal_type(x)  # revealed: int
 ```
 
 ## An if statement without an explicit `else` branch is equivalent to one with a no-op `else` branch
 
 ```py
-def _(x: int | None, y: int | None):
-    if x is None:
-        x = 0
+def optional_int() -> int | None: ...
 
-    if y is None:
-        pass
+x = optional_int()
+y = optional_int()
 
-    reveal_type(x)  # revealed: int
-    reveal_type(y)  # revealed: int | None
+if x is None:
+    x = 0
+
+if y is None:
+    pass
+
+reveal_type(x)  # revealed: int
+reveal_type(y)  # revealed: int | None
 ```
 
 ## An if-elif without an explicit else branch is equivalent to one with an empty else branch
 
 ```py
-def _(x: int | None):
-    if x is None:
-        x = 0
-    elif x > 50:
-        x = 50
+def optional_int() -> int | None: ...
 
-    reveal_type(x)  # revealed: int
+x = optional_int()
+
+if x is None:
+    x = 0
+elif x > 50:
+    x = 50
+
+reveal_type(x)  # revealed: int
 ```

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

@@ -6,14 +6,18 @@
 class A: ...
 class B: ...
 
-def _(x: A | B):
-    if type(x) is A:
-        reveal_type(x)  # revealed: A
-    else:
-        # It would be wrong to infer `B` here. The type
-        # of `x` could be a subclass of `A`, so we need
-        # to infer the full union type:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is A:
+    reveal_type(x)  # revealed: A
+else:
+    # It would be wrong to infer `B` here. The type
+    # of `x` could be a subclass of `A`, so we need
+    # to infer the full union type:
+    reveal_type(x)  # revealed: A | B
 ```
 
 ## `type(x) is not C`
@@ -22,12 +26,16 @@ def _(x: A | B):
 class A: ...
 class B: ...
 
-def _(x: A | B):
-    if type(x) is not A:
-        # Same reasoning as above: no narrowing should occur here.
-        reveal_type(x)  # revealed: A | B
-    else:
-        reveal_type(x)  # revealed: A
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is not A:
+    # Same reasoning as above: no narrowing should occur here.
+    reveal_type(x)  # revealed: A | B
+else:
+    reveal_type(x)  # revealed: A
 ```
 
 ## `type(x) == C`, `type(x) != C`
@@ -46,12 +54,16 @@ class IsEqualToEverything(type):
 class A(metaclass=IsEqualToEverything): ...
 class B(metaclass=IsEqualToEverything): ...
 
-def _(x: A | B):
-    if type(x) == A:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return B()
 
-    if type(x) != A:
-        reveal_type(x)  # revealed: A | B
+x = get_a_or_b()
+
+if type(x) == A:
+    reveal_type(x)  # revealed: A | B
+
+if type(x) != A:
+    reveal_type(x)  # revealed: A | B
 ```
 
 ## No narrowing for custom `type` callable
@@ -63,11 +75,15 @@ class B: ...
 def type(x):
     return int
 
-def _(x: A | B):
-    if type(x) is A:
-        reveal_type(x)  # revealed: A | B
-    else:
-        reveal_type(x)  # revealed: A | B
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if type(x) is A:
+    reveal_type(x)  # revealed: A | B
+else:
+    reveal_type(x)  # revealed: A | B
 ```
 
 ## No narrowing for multiple arguments
@@ -75,11 +91,15 @@ def _(x: A | B):
 No narrowing should occur if `type` is used to dynamically create a class:
 
 ```py
-def _(x: str | int):
-    if type(x, (), {}) is str:
-        reveal_type(x)  # revealed: str | int
-    else:
-        reveal_type(x)  # revealed: str | int
+def get_str_or_int() -> str | int:
+    return "test"
+
+x = get_str_or_int()
+
+if type(x, (), {}) is str:
+    reveal_type(x)  # revealed: str | int
+else:
+    reveal_type(x)  # revealed: str | int
 ```
 
 ## No narrowing for keyword arguments
@@ -87,10 +107,14 @@ def _(x: str | int):
 `type` can't be used with a keyword argument:
 
 ```py
-def _(x: str | int):
-    # TODO: we could issue a diagnostic here
-    if type(object=x) is str:
-        reveal_type(x)  # revealed: str | int
+def get_str_or_int() -> str | int:
+    return "test"
+
+x = get_str_or_int()
+
+# TODO: we could issue a diagnostic here
+if type(object=x) is str:
+    reveal_type(x)  # revealed: str | int
 ```
 
 ## Narrowing if `type` is aliased
@@ -101,9 +125,13 @@ class B: ...
 
 alias_for_type = type
 
-def _(x: A | B):
-    if alias_for_type(x) is A:
-        reveal_type(x)  # revealed: A
+def get_a_or_b() -> A | B:
+    return A()
+
+x = get_a_or_b()
+
+if alias_for_type(x) is A:
+    reveal_type(x)  # revealed: A
 ```
 
 ## Limitations
@@ -112,9 +140,13 @@ def _(x: A | B):
 class Base: ...
 class Derived(Base): ...
 
-def _(x: Base):
-    if type(x) is Base:
-        # Ideally, this could be narrower, but there is now way to
-        # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
-        reveal_type(x)  # revealed: Base
+def get_base() -> Base:
+    return Base()
+
+x = get_base()
+
+if type(x) is Base:
+    # Ideally, this could be narrower, but there is now way to
+    # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
+    reveal_type(x)  # revealed: Base
 ```

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

@@ -1,58 +0,0 @@
-# Narrowing in `while` loops
-
-We only make sure that narrowing works for `while` loops in general, we do not exhaustively test all
-narrowing forms here, as they are covered in other tests.
-
-Note how type narrowing works subtly different from `if` ... `else`, because the negated constraint
-is retained after the loop.
-
-## Basic `while` loop
-
-```py
-def next_item() -> int | None: ...
-
-x = next_item()
-
-while x is not None:
-    reveal_type(x)  # revealed: int
-    x = next_item()
-
-reveal_type(x)  # revealed: None
-```
-
-## `while` loop with `else`
-
-```py
-def next_item() -> int | None: ...
-
-x = next_item()
-
-while x is not None:
-    reveal_type(x)  # revealed: int
-    x = next_item()
-else:
-    reveal_type(x)  # revealed: None
-
-reveal_type(x)  # revealed: None
-```
-
-## Nested `while` loops
-
-```py
-from typing import Literal
-
-def next_item() -> Literal[1, 2, 3]: ...
-
-x = next_item()
-
-while x != 1:
-    reveal_type(x)  # revealed: Literal[2, 3]
-
-    while x != 2:
-        # TODO: this should be Literal[1, 3]; Literal[3] is only correct
-        # in the first loop iteration
-        reveal_type(x)  # revealed: Literal[3]
-        x = next_item()
-
-    x = next_item()
-```

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

@@ -10,10 +10,10 @@ def returns_bool() -> bool:
     return True
 
 if returns_bool():
-    chr = 1
+    copyright = 1
 
 def f():
-    reveal_type(chr)  # revealed: Literal[chr] | Literal[1]
+    reveal_type(copyright)  # revealed: Literal[copyright] | Literal[1]
 ```
 
 ## Conditionally global or builtin, with annotation
@@ -25,8 +25,8 @@ def returns_bool() -> bool:
     return True
 
 if returns_bool():
-    chr: int = 1
+    copyright: int = 1
 
 def f():
-    reveal_type(chr)  # revealed: Literal[chr] | int
+    reveal_type(copyright)  # revealed: Literal[copyright] | int
 ```

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

@@ -59,7 +59,7 @@ reveal_type(typing.__init__)  # revealed: Literal[__init__]
 # These come from `builtins.object`, not `types.ModuleType`:
 reveal_type(typing.__eq__)  # revealed: Literal[__eq__]
 
-reveal_type(typing.__class__)  # revealed: Literal[ModuleType]
+reveal_type(typing.__class__)  # revealed: Literal[type]
 
 # TODO: needs support for attribute access on instances, properties and generics;
 # should be `dict[str, Any]`

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

@@ -5,10 +5,10 @@
 Name lookups within a class scope fall back to globals, but lookups of class attributes don't.
 
 ```py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-flag = coinflip()
+flag = bool_instance()
 x = 1
 
 class C:
@@ -24,14 +24,14 @@ reveal_type(C.y)  # revealed: Literal[1]
 ## Possibly unbound in class and global scope
 
 ```py
-def coinflip() -> bool:
+def bool_instance() -> bool:
     return True
 
-if coinflip():
+if bool_instance():
     x = "abc"
 
 class C:
-    if coinflip():
+    if bool_instance():
         x = 1
 
     # error: [possibly-unresolved-reference]

crates/red_knot_python_semantic/resources/mdtest/shadowing/variable_declaration.md

@@ -3,11 +3,14 @@
 ## Shadow after incompatible declarations is OK
 
 ```py
-def _(flag: bool):
-    if flag:
-        x: str
-    else:
-        x: int
+def bool_instance() -> bool:
+    return True
 
-    x: bytes = b"foo"
+flag = bool_instance()
+
+if flag:
+    x: str
+else:
+    x: int
+x: bytes = b"foo"
 ```

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

@@ -22,10 +22,12 @@ reveal_type(x)  # revealed: Unknown
 y = b[-6]  # error: [index-out-of-bounds] "Index -6 is out of bounds for bytes literal `Literal[b"\x00abc\xff"]` with length 5"
 reveal_type(y)  # revealed: Unknown
 
-def _(n: int):
-    a = b"abcde"[n]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(a)  # revealed: @Todo(return type)
+def int_instance() -> int:
+    return 42
+
+a = b"abcde"[int_instance()]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(a)  # revealed: @Todo(return type)
 ```
 
 ## Slices
@@ -41,13 +43,15 @@ b[:4:0]  # error: [zero-stepsize-in-slice]
 b[0::0]  # error: [zero-stepsize-in-slice]
 b[::0]  # error: [zero-stepsize-in-slice]
 
-def _(m: int, n: int):
-    byte_slice1 = b[m:n]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(byte_slice1)  # revealed: @Todo(return type)
+def int_instance() -> int: ...
 
-def _(s: bytes) -> bytes:
-    byte_slice2 = s[0:5]
-    # TODO: Support overloads... Should be `bytes`
-    reveal_type(byte_slice2)  # revealed: @Todo(return type)
+byte_slice1 = b[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(byte_slice1)  # revealed: @Todo(return type)
+
+def bytes_instance() -> bytes: ...
+
+byte_slice2 = bytes_instance()[0:5]
+# TODO: Support overloads... Should be `bytes`
+reveal_type(byte_slice2)  # revealed: @Todo(return type)
 ```

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

@@ -21,66 +21,77 @@ reveal_type(Identity[0])  # revealed: str
 ## Class getitem union
 
 ```py
-def _(flag: bool):
-    class UnionClassGetItem:
-        if flag:
-            def __class_getitem__(cls, item: int) -> str:
-                return item
-        else:
-            def __class_getitem__(cls, item: int) -> int:
-                return item
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(UnionClassGetItem[0])  # revealed: str | int
+class UnionClassGetItem:
+    if bool_instance():
+
+        def __class_getitem__(cls, item: int) -> str:
+            return item
+    else:
+
+        def __class_getitem__(cls, item: int) -> int:
+            return item
+
+reveal_type(UnionClassGetItem[0])  # revealed: str | int
 ```
 
 ## Class getitem with class union
 
 ```py
-def _(flag: bool):
-    class A:
-        def __class_getitem__(cls, item: int) -> str:
-            return item
+def bool_instance() -> bool:
+    return True
 
-    class B:
-        def __class_getitem__(cls, item: int) -> int:
-            return item
+class A:
+    def __class_getitem__(cls, item: int) -> str:
+        return item
 
-    x = A if flag else B
+class B:
+    def __class_getitem__(cls, item: int) -> int:
+        return item
 
-    reveal_type(x)  # revealed: Literal[A, B]
-    reveal_type(x[0])  # revealed: str | int
+x = A if bool_instance() else B
+
+reveal_type(x)  # revealed: Literal[A, B]
+reveal_type(x[0])  # revealed: str | int
 ```
 
 ## Class getitem with unbound method union
 
 ```py
-def _(flag: bool):
-    if flag:
-        class Spam:
-            def __class_getitem__(self, x: int) -> str:
-                return "foo"
+def bool_instance() -> bool:
+    return True
 
-    else:
-        class Spam: ...
-    # error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[Spam, Spam]` is possibly unbound"
-    # revealed: str
-    reveal_type(Spam[42])
+if bool_instance():
+    class Spam:
+        def __class_getitem__(self, x: int) -> str:
+            return "foo"
+
+else:
+    class Spam: ...
+
+# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[Spam, Spam]` is possibly unbound"
+# revealed: str
+reveal_type(Spam[42])
 ```
 
 ## TODO: Class getitem non-class union
 
 ```py
-def _(flag: bool):
-    if flag:
-        class Eggs:
-            def __class_getitem__(self, x: int) -> str:
-                return "foo"
+def bool_instance() -> bool:
+    return True
 
-    else:
-        Eggs = 1
+if bool_instance():
+    class Eggs:
+        def __class_getitem__(self, x: int) -> str:
+            return "foo"
 
-    a = Eggs[42]  # error: "Cannot subscript object of type `Literal[Eggs] | Literal[1]` with no `__getitem__` method"
+else:
+    Eggs = 1
 
-    # TODO: should _probably_ emit `str | Unknown`
-    reveal_type(a)  # revealed: Unknown
+a = Eggs[42]  # error: "Cannot subscript object of type `Literal[Eggs] | Literal[1]` with no `__getitem__` method"
+
+# TODO: should _probably_ emit `str | Unknown`
+reveal_type(a)  # revealed: Unknown
 ```

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

@@ -30,14 +30,18 @@ reveal_type(Identity()[0])  # revealed: int
 ## Getitem union
 
 ```py
-def _(flag: bool):
-    class Identity:
-        if flag:
-            def __getitem__(self, index: int) -> int:
-                return index
-        else:
-            def __getitem__(self, index: int) -> str:
-                return str(index)
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(Identity()[0])  # revealed: int | str
+class Identity:
+    if bool_instance():
+
+        def __getitem__(self, index: int) -> int:
+            return index
+    else:
+
+        def __getitem__(self, index: int) -> str:
+            return str(index)
+
+reveal_type(Identity()[0])  # revealed: int | str
 ```

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

@@ -19,10 +19,11 @@ reveal_type(a)  # revealed: Unknown
 b = s[-8]  # error: [index-out-of-bounds] "Index -8 is out of bounds for string `Literal["abcde"]` with length 5"
 reveal_type(b)  # revealed: Unknown
 
-def _(n: int):
-    a = "abcde"[n]
-    # TODO: Support overloads... Should be `str`
-    reveal_type(a)  # revealed: @Todo(return type)
+def int_instance() -> int: ...
+
+a = "abcde"[int_instance()]
+# TODO: Support overloads... Should be `str`
+reveal_type(a)  # revealed: @Todo(return type)
 ```
 
 ## Slices
@@ -73,14 +74,17 @@ s[:4:0]  # error: [zero-stepsize-in-slice]
 s[0::0]  # error: [zero-stepsize-in-slice]
 s[::0]  # error: [zero-stepsize-in-slice]
 
-def _(m: int, n: int, s2: str):
-    substring1 = s[m:n]
-    # TODO: Support overloads... Should be `LiteralString`
-    reveal_type(substring1)  # revealed: @Todo(return type)
+def int_instance() -> int: ...
 
-    substring2 = s2[0:5]
-    # TODO: Support overloads... Should be `str`
-    reveal_type(substring2)  # revealed: @Todo(return type)
+substring1 = s[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `LiteralString`
+reveal_type(substring1)  # revealed: @Todo(return type)
+
+def str_instance() -> str: ...
+
+substring2 = str_instance()[0:5]
+# TODO: Support overloads... Should be `str`
+reveal_type(substring2)  # revealed: @Todo(return type)
 ```
 
 ## Unsupported slice types

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

@@ -67,60 +67,9 @@ t[:4:0]  # error: [zero-stepsize-in-slice]
 t[0::0]  # error: [zero-stepsize-in-slice]
 t[::0]  # error: [zero-stepsize-in-slice]
 
-def _(m: int, n: int):
-    tuple_slice = t[m:n]
-    # TODO: Support overloads... Should be `tuple[Literal[1, 'a', b"b"] | None, ...]`
-    reveal_type(tuple_slice)  # revealed: @Todo(return type)
-```
-
-## Inheritance
-
-```toml
-[environment]
-python-version = "3.9"
-```
-
-```py
-# TODO:
-#  * `tuple.__class_getitem__` is always bound on 3.9 (`sys.version_info`)
-#  * `tuple[int, str]` is a valid base (generics)
-# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[tuple]` is possibly unbound"
-# error: [invalid-base] "Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class A(tuple[int, str]): ...
-
-# Runtime value: `(A, tuple, object)`
-# TODO: Generics
-reveal_type(A.__mro__)  # revealed: tuple[Literal[A], Unknown, Literal[object]]
-```
-
-## `typing.Tuple`
-
-### Correspondence with `tuple`
-
-`typing.Tuple` can be used interchangeably with `tuple`:
-
-```py
-from typing import Tuple
-
-class A: ...
-
-def _(c: Tuple, d: Tuple[int, A], e: Tuple[Any, ...]):
-    reveal_type(c)  # revealed: tuple
-    reveal_type(d)  # revealed: tuple[int, A]
-    reveal_type(e)  # revealed: @Todo(full tuple[...] support)
-```
-
-### Inheritance
-
-Inheriting from `Tuple` results in a MRO with `builtins.tuple` and `typing.Generic`. `Tuple` itself
-is not a class.
-
-```py
-from typing import Tuple
-
-class C(Tuple): ...
-
-# Runtime value: `(C, tuple, typing.Generic, object)`
-# TODO: Add `Generic` to the MRO
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[tuple], Unknown, Literal[object]]
+def int_instance() -> int: ...
+
+tuple_slice = t[int_instance() : int_instance()]
+# TODO: Support overloads... Should be `tuple[Literal[1, 'a', b"b"] | None, ...]`
+reveal_type(tuple_slice)  # revealed: @Todo(return type)
 ```

crates/red_knot_python_semantic/resources/mdtest/sys_version_info.md

@@ -2,7 +2,7 @@
 
 ```toml
 [environment]
-python-version = "3.9"
+target-version = "3.9"
 ```
 
 ## The type of `sys.version_info`

crates/red_knot_python_semantic/resources/mdtest/type_alias.md

@@ -1,11 +1,4 @@
-# PEP 695 type aliases
-
-PEP 695 type aliases are only available in Python 3.12 and later:
-
-```toml
-[environment]
-python-version = "3.12"
-```
+# Type aliases
 
 ## Basic
 

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

@@ -5,8 +5,10 @@
 ```py
 class A: ...
 
-def _(c: type[A]):
-    reveal_type(c)  # revealed: type[A]
+def f() -> type[A]:
+    return A
+
+reveal_type(f())  # revealed: type[A]
 ```
 
 ## Nested class literal
@@ -15,8 +17,10 @@ def _(c: type[A]):
 class A:
     class B: ...
 
-def f(c: type[A.B]):
-    reveal_type(c)  # revealed: type[B]
+def f() -> type[A.B]:
+    return A.B
+
+reveal_type(f())  # revealed: type[B]
 ```
 
 ## Deeply nested class literal
@@ -26,8 +30,10 @@ class A:
     class B:
         class C: ...
 
-def f(c: type[A.B.C]):
-    reveal_type(c)  # revealed: type[C]
+def f() -> type[A.B.C]:
+    return A.B.C
+
+reveal_type(f())  # revealed: type[C]
 ```
 
 ## Class literal from another module
@@ -35,8 +41,10 @@ def f(c: type[A.B.C]):
 ```py
 from a import A
 
-def f(c: type[A]):
-    reveal_type(c)  # revealed: type[A]
+def f() -> type[A]:
+    return A
+
+reveal_type(f())  # revealed: type[A]
 ```
 
 ```py path=a.py
@@ -48,8 +56,10 @@ class A: ...
 ```py
 import a
 
-def f(c: type[a.B]):
-    reveal_type(c)  # revealed: type[B]
+def f() -> type[a.B]:
+    return a.B
+
+reveal_type(f())  # revealed: type[B]
 ```
 
 ```py path=a.py
@@ -63,8 +73,12 @@ import a.b
 
 # TODO: no diagnostic
 # error: [unresolved-attribute]
-def f(c: type[a.b.C]):
-    reveal_type(c)  # revealed: @Todo(unsupported type[X] special form)
+def f() -> type[a.b.C]:
+    # TODO: no diagnostic
+    # error: [unresolved-attribute]
+    return a.b.C
+
+reveal_type(f())  # revealed: @Todo(unsupported type[X] special form)
 ```
 
 ```py path=a/__init__.py
@@ -74,7 +88,7 @@ def f(c: type[a.b.C]):
 class C: ...
 ```
 
-## New-style union of classes
+## Union of classes
 
 ```py
 class BasicUser: ...
@@ -84,44 +98,11 @@ class A:
     class B:
         class C: ...
 
-def _(u: type[BasicUser | ProUser | A.B.C]):
-    # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(u)
-```
+def get_user() -> type[BasicUser | ProUser | A.B.C]:
+    return BasicUser
 
-## Old-style union of classes
-
-```py
-from typing import Union
-
-class BasicUser: ...
-class ProUser: ...
-
-class A:
-    class B:
-        class C: ...
-
-def f(a: type[Union[BasicUser, ProUser, A.B.C]], b: type[Union[str]], c: type[Union[BasicUser, Union[ProUser, A.B.C]]]):
-    reveal_type(a)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(b)  # revealed: type[str]
-    reveal_type(c)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-```
-
-## New-style and old-style unions in combination
-
-```py
-from typing import Union
-
-class BasicUser: ...
-class ProUser: ...
-
-class A:
-    class B:
-        class C: ...
-
-def f(a: type[BasicUser | Union[ProUser, A.B.C]], b: type[Union[BasicUser | Union[ProUser, A.B.C | str]]]):
-    reveal_type(a)  # revealed: type[BasicUser] | type[ProUser] | type[C]
-    reveal_type(b)  # revealed: type[BasicUser] | type[ProUser] | type[C] | type[str]
+# revealed: type[BasicUser] | type[ProUser] | type[C]
+reveal_type(get_user())
 ```
 
 ## Illegal parameters
@@ -131,16 +112,6 @@ class A: ...
 class B: ...
 
 # error: [invalid-type-form]
-_: type[A, B]
-```
-
-## As a base class
-
-```py
-# TODO: this is a false positive
-# error: [invalid-base] "Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
-class Foo(type[int]): ...
-
-# TODO: should be `tuple[Literal[Foo], Literal[type], Literal[object]]
-reveal_type(Foo.__mro__)  # revealed: tuple[Literal[Foo], Unknown, Literal[object]]
+def get_user() -> type[A, B]:
+    return A
 ```

crates/red_knot_python_semantic/resources/mdtest/type_of/dynamic.md

@@ -1,102 +0,0 @@
-# `type[Any]`
-
-This file contains tests for non-fully-static `type[]` types, such as `type[Any]` and
-`type[Unknown]`.
-
-## Simple
-
-```py
-def f(x: type[Any], y: type[str]):
-    reveal_type(x)  # revealed: type[Any]
-    # TODO: could be `<object.__repr__ type> & Any`
-    reveal_type(x.__repr__)  # revealed: Any
-
-    # type[str] and type[Any] are assignable to each other
-    a: type[str] = x
-    b: type[Any] = y
-
-class A: ...
-
-x: type[Any] = object
-x: type[Any] = type
-x: type[Any] = A
-x: type[Any] = A()  # error: [invalid-assignment]
-```
-
-## Bare type
-
-The interpretation of bare `type` is not clear: existing wording in the spec does not match the
-behavior of mypy or pyright. For now we interpret it as simply "an instance of `builtins.type`",
-which is equivalent to `type[object]`. This is similar to the current behavior of mypy, and pyright
-in strict mode.
-
-```py
-def f(x: type):
-    reveal_type(x)  # revealed: type
-    reveal_type(x.__repr__)  # revealed: @Todo(instance attributes)
-
-class A: ...
-
-x: type = object
-x: type = type
-x: type = A
-x: type = A()  # error: [invalid-assignment]
-```
-
-## type[object] != type[Any]
-
-```py
-def f(x: type[object]):
-    reveal_type(x)  # revealed: type[object]
-    # TODO: bound method types
-    reveal_type(x.__repr__)  # revealed: Literal[__repr__]
-
-class A: ...
-
-x: type[object] = object
-x: type[object] = type
-x: type[object] = A
-x: type[object] = A()  # error: [invalid-assignment]
-```
-
-## The type of `Any` is `type[Any]`
-
-`Any` represents an unknown set of possible runtime values. If `x` is of type `Any`, the type of
-`x.__class__` is also unknown and remains dynamic, *except* that we know it must be a class object
-of some kind. As such, the type of `x.__class__` is `type[Any]` rather than `Any`:
-
-```py
-from typing import Any
-from does_not_exist import SomethingUnknown  # error: [unresolved-import]
-
-reveal_type(SomethingUnknown)  # revealed: Unknown
-
-def test(x: Any, y: SomethingUnknown):
-    reveal_type(x.__class__)  # revealed: type[Any]
-    reveal_type(x.__class__.__class__.__class__.__class__)  # revealed: type[Any]
-    reveal_type(y.__class__)  # revealed: type[Unknown]
-    reveal_type(y.__class__.__class__.__class__.__class__)  # revealed: type[Unknown]
-```
-
-## `type[Unknown]` has similar properties to `type[Any]`
-
-```py
-import abc
-from typing import Any
-from does_not_exist import SomethingUnknown  # error: [unresolved-import]
-
-has_unknown_type = SomethingUnknown.__class__
-reveal_type(has_unknown_type)  # revealed: type[Unknown]
-
-def test(x: type[str], y: type[Any]):
-    """Both `type[Any]` and `type[Unknown]` are assignable to all `type[]` types"""
-    a: type[Any] = x
-    b: type[str] = y
-    c: type[Any] = has_unknown_type
-    d: type[str] = has_unknown_type
-
-def test2(a: type[Any]):
-    """`type[Any]` and `type[Unknown]` are also assignable to all instances of `type` subclasses"""
-    b: abc.ABCMeta = a
-    b: abc.ABCMeta = has_unknown_type
-```

crates/red_knot_python_semantic/resources/mdtest/type_of/typing_dot_Type.md

@@ -1,32 +0,0 @@
-# `typing.Type`
-
-## Annotation
-
-`typing.Type` can be used interchangeably with `type`:
-
-```py
-from typing import Type
-
-class A: ...
-
-def _(c: Type, d: Type[A]):
-    reveal_type(c)  # revealed: type
-    reveal_type(d)  # revealed: type[A]
-    c = d  # fine
-    d = c  # fine
-```
-
-## Inheritance
-
-Inheriting from `Type` results in a MRO with `builtins.type` and `typing.Generic`. `Type` itself is
-not a class.
-
-```py
-from typing import Type
-
-class C(Type): ...
-
-# Runtime value: `(C, type, typing.Generic, object)`
-# TODO: Add `Generic` to the MRO
-reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[type], Literal[object]]
-```

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

@@ -35,25 +35,29 @@ y = 1
 ## Union
 
 ```py
-def _(flag: bool):
-    if flag:
-        p = 1
-        q = 3.3
-        r = "hello"
-        s = "world"
-        t = 0
-    else:
-        p = "hello"
-        q = 4
-        r = ""
-        s = 0
-        t = ""
+def bool_instance() -> bool:
+    return True
 
-    reveal_type(not p)  # revealed: Literal[False]
-    reveal_type(not q)  # revealed: bool
-    reveal_type(not r)  # revealed: bool
-    reveal_type(not s)  # revealed: bool
-    reveal_type(not t)  # revealed: Literal[True]
+flag = bool_instance()
+
+if flag:
+    p = 1
+    q = 3.3
+    r = "hello"
+    s = "world"
+    t = 0
+else:
+    p = "hello"
+    q = 4
+    r = ""
+    s = 0
+    t = ""
+
+reveal_type(not p)  # revealed: Literal[False]
+reveal_type(not q)  # revealed: bool
+reveal_type(not r)  # revealed: bool
+reveal_type(not s)  # revealed: bool
+reveal_type(not t)  # revealed: Literal[True]
 ```
 
 ## Integer literal

crates/red_knot_python_semantic/resources/mdtest/with/sync.md

@@ -21,23 +21,25 @@ with Manager() as f:
 ## Union context manager
 
 ```py
-def _(flag: bool):
-    class Manager1:
-        def __enter__(self) -> str:
-            return "foo"
+def coinflip() -> bool:
+    return True
 
-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager1:
+    def __enter__(self) -> str:
+        return "foo"
 
-    class Manager2:
-        def __enter__(self) -> int:
-            return 42
+    def __exit__(self, exc_type, exc_value, traceback): ...
 
-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager2:
+    def __enter__(self) -> int:
+        return 42
 
-    context_expr = Manager1() if flag else Manager2()
+    def __exit__(self, exc_type, exc_value, traceback): ...
 
-    with context_expr as f:
-        reveal_type(f)  # revealed: str | int
+context_expr = Manager1() if coinflip() else Manager2()
+
+with context_expr as f:
+    reveal_type(f)  # revealed: str | int
 ```
 
 ## Context manager without an `__enter__` or `__exit__` method
@@ -101,34 +103,39 @@ with Manager():
 ## Context expression with possibly-unbound union variants
 
 ```py
-def _(flag: bool):
-    class Manager1:
-        def __enter__(self) -> str:
-            return "foo"
+def coinflip() -> bool:
+    return True
 
-        def __exit__(self, exc_type, exc_value, traceback): ...
+class Manager1:
+    def __enter__(self) -> str:
+        return "foo"
 
-    class NotAContextManager: ...
-    context_expr = Manager1() if flag else NotAContextManager()
+    def __exit__(self, exc_type, exc_value, traceback): ...
 
-    # error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-    # error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__exit__` is possibly unbound"
-    with context_expr as f:
-        reveal_type(f)  # revealed: str
+class NotAContextManager: ...
+
+context_expr = Manager1() if coinflip() else NotAContextManager()
+
+# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__enter__` is possibly unbound"
+# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__exit__` is possibly unbound"
+with context_expr as f:
+    reveal_type(f)  # revealed: str
 ```
 
 ## Context expression with "sometimes" callable `__enter__` method
 
 ```py
-def _(flag: bool):
-    class Manager:
-        if flag:
-            def __enter__(self) -> str:
-                return "abcd"
+def coinflip() -> bool:
+    return True
 
-        def __exit__(self, *args): ...
+class Manager:
+    if coinflip():
+        def __enter__(self) -> str:
+            return "abcd"
 
-    # error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-    with Manager() as f:
-        reveal_type(f)  # revealed: str
+    def __exit__(self, *args): ...
+
+# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` is possibly unbound"
+with Manager() as f:
+    reveal_type(f)  # revealed: str
 ```

crates/red_knot_python_semantic/src/db.rs

@@ -166,12 +166,12 @@ pub(crate) mod tests {
                 .context("Failed to write test files")?;
 
             let mut search_paths = SearchPathSettings::new(src_root);
-            search_paths.typeshed = self.custom_typeshed;
+            search_paths.custom_typeshed = self.custom_typeshed;
 
             Program::from_settings(
                 &db,
                 &ProgramSettings {
-                    python_version: self.python_version,
+                    target_version: self.python_version,
                     search_paths,
                 },
             )

crates/red_knot_python_semantic/src/lib.rs

@@ -29,14 +29,12 @@ mod util;
 
 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;
 
-/// Creates a new registry with all known semantic lints.
 pub fn default_lint_registry() -> LintRegistry {
     let mut registry = LintRegistryBuilder::default();
-    register_lints(&mut registry);
+    register_semantic_lints(&mut registry);
     registry.build()
 }
 
-/// Register all known semantic lints.
-pub fn register_lints(registry: &mut LintRegistryBuilder) {
-    types::register_lints(registry);
+pub fn register_semantic_lints(registry: &mut LintRegistryBuilder) {
+    types::register_type_lints(registry);
 }

crates/red_knot_python_semantic/src/lint.rs

@@ -23,11 +23,8 @@ pub struct LintMetadata {
 
     pub status: LintStatus,
 
-    /// The source file in which the lint is declared.
-    pub file: &'static str,
-
-    /// The 1-based line number in the source `file` where the lint is declared.
-    pub line: u32,
+    /// Location where this lint is declared: `file_name:line`
+    pub source: &'static str,
 }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
@@ -77,7 +74,7 @@ impl LintMetadata {
         self.summary
     }
 
-    /// Returns the documentation line by line with one leading space and all trailing whitespace removed.
+    /// Returns the documentation line by line with leading and trailing whitespace removed.
     pub fn documentation_lines(&self) -> impl Iterator<Item = &str> {
         self.raw_documentation
             .lines()
@@ -97,12 +94,8 @@ impl LintMetadata {
         &self.status
     }
 
-    pub fn file(&self) -> &str {
-        self.file
-    }
-
-    pub fn line(&self) -> u32 {
-        self.line
+    pub fn source(&self) -> &str {
+        self.source
     }
 }
 
@@ -114,43 +107,30 @@ pub const fn lint_metadata_defaults() -> LintMetadata {
         raw_documentation: "",
         default_level: Level::Error,
         status: LintStatus::preview("0.0.0"),
-        file: "",
-        line: 1,
+        source: "",
     }
 }
 
 #[derive(Copy, Clone, Debug)]
 pub enum LintStatus {
-    /// The lint has been added to the linter, but is not yet stable.
+    /// The rule has been added to the linter, but is not yet stable.
     Preview {
-        /// The version in which the lint was added.
+        /// When the rule was added to preview
         since: &'static str,
     },
 
-    /// The lint is stable.
-    Stable {
-        /// The version in which the lint was stabilized.
-        since: &'static str,
-    },
+    /// Stable rule that was added in the version defined by `since`.
+    Stable { since: &'static str },
 
-    /// The lint is deprecated and no longer recommended for use.
+    /// The rule has been deprecated [`since`] (version) and will be removed in the future.
     Deprecated {
-        /// The version in which the lint was deprecated.
         since: &'static str,
-
-        /// The reason why the lint has been deprecated.
-        ///
-        /// This should explain why the lint has been deprecated and if there's a replacement lint that users
-        /// can use instead.
         reason: &'static str,
     },
 
-    /// The lint has been removed and can no longer be used.
+    /// The rule has been removed [`since`] (version) and using it will result in an error.
     Removed {
-        /// The version in which the lint was removed.
         since: &'static str,
-
-        /// The reason why the lint has been removed.
         reason: &'static str,
     },
 }
@@ -177,31 +157,6 @@ impl LintStatus {
     }
 }
 
-/// Declares a lint rule with the given metadata.
-///
-/// ```rust
-/// use red_knot_python_semantic::declare_lint;
-/// use red_knot_python_semantic::lint::{LintStatus, Level};
-///
-/// declare_lint! {
-///     /// ## What it does
-///     /// Checks for references to names that are not defined.
-///     ///
-///     /// ## Why is this bad?
-///     /// Using an undefined variable will raise a `NameError` at runtime.
-///     ///
-///     /// ## Example
-///     ///
-///     /// ```python
-///     /// print(x)  # NameError: name 'x' is not defined
-///     /// ```
-///     pub(crate) static UNRESOLVED_REFERENCE = {
-///         summary: "detects references to names that are not defined",
-///         status: LintStatus::preview("1.0.0"),
-///         default_level: Level::Warn,
-///     }
-/// }
-/// ```
 #[macro_export]
 macro_rules! declare_lint {
     (
@@ -220,8 +175,7 @@ macro_rules! declare_lint {
             summary: $summary,
             raw_documentation: concat!($($doc,)+ "\n"),
             status: $status,
-            file: file!(),
-            line: line!(),
+            source: concat!(file!(), ":", line!()),
             $( $key: $value, )*
             ..$crate::lint::lint_metadata_defaults()
         };
@@ -352,7 +306,7 @@ impl LintRegistry {
     /// Returns an iterator over all known aliases and to their target lints.
     ///
     /// This iterator includes aliases that point to removed lints.
-    pub fn aliases(&self) -> impl Iterator<Item = (LintName, LintId)> + '_ {
+    pub fn aliases(&self) -> impl Iterator<Item = (LintName, LintId)> + use<'_> {
         self.by_name.iter().filter_map(|(key, value)| {
             if let LintEntry::Alias(alias) = value {
                 Some((LintName::of(key), *alias))
@@ -363,7 +317,7 @@ impl LintRegistry {
     }
 
     /// Iterates over all removed lints.
-    pub fn removed(&self) -> impl Iterator<Item = LintId> + '_ {
+    pub fn removed(&self) -> impl Iterator<Item = LintId> + use<'_> {
         self.by_name.iter().filter_map(|(_, value)| {
             if let LintEntry::Removed(metadata) = value {
                 Some(*metadata)
@@ -430,12 +384,12 @@ impl RuleSelection {
     }
 
     /// Returns an iterator over all enabled lints.
-    pub fn enabled(&self) -> impl Iterator<Item = LintId> + '_ {
+    pub fn enabled(&self) -> impl Iterator<Item = LintId> + use<'_> {
         self.lints.keys().copied()
     }
 
     /// Returns an iterator over all enabled lints and their severity.
-    pub fn iter(&self) -> impl ExactSizeIterator<Item = (LintId, Severity)> + '_ {
+    pub fn iter(&self) -> impl ExactSizeIterator<Item = (LintId, Severity)> + use<'_> {
         self.lints.iter().map(|(&lint, &severity)| (lint, severity))
     }
 

crates/red_knot_python_semantic/src/module_resolver/path.rs

@@ -283,9 +283,9 @@ fn query_stdlib_version(
     let Some(module_name) = stdlib_path_to_module_name(relative_path) else {
         return TypeshedVersionsQueryResult::DoesNotExist;
     };
-    let ResolverContext { db, python_version } = context;
+    let ResolverContext { db, target_version } = context;
 
-    typeshed_versions(*db).query_module(&module_name, *python_version)
+    typeshed_versions(*db).query_module(&module_name, *target_version)
 }
 
 /// Enumeration describing the various ways in which validation of a search path might fail.
@@ -658,7 +658,7 @@ mod tests {
         let TestCase {
             db, src, stdlib, ..
         } = TestCaseBuilder::new()
-            .with_mocked_typeshed(MockedTypeshed::default())
+            .with_custom_typeshed(MockedTypeshed::default())
             .build();
 
         assert_eq!(
@@ -779,7 +779,7 @@ mod tests {
     #[should_panic(expected = "Extension must be `pyi`; got `py`")]
     fn stdlib_path_invalid_join_py() {
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(MockedTypeshed::default())
+            .with_custom_typeshed(MockedTypeshed::default())
             .build();
         SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
             .unwrap()
@@ -791,7 +791,7 @@ mod tests {
     #[should_panic(expected = "Extension must be `pyi`; got `rs`")]
     fn stdlib_path_invalid_join_rs() {
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(MockedTypeshed::default())
+            .with_custom_typeshed(MockedTypeshed::default())
             .build();
         SearchPath::custom_stdlib(&db, stdlib.parent().unwrap())
             .unwrap()
@@ -822,7 +822,7 @@ mod tests {
     #[test]
     fn relativize_stdlib_path_errors() {
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(MockedTypeshed::default())
+            .with_custom_typeshed(MockedTypeshed::default())
             .build();
 
         let root = SearchPath::custom_stdlib(&db, stdlib.parent().unwrap()).unwrap();
@@ -867,11 +867,11 @@ mod tests {
 
     fn typeshed_test_case(
         typeshed: MockedTypeshed,
-        python_version: PythonVersion,
+        target_version: PythonVersion,
     ) -> (TestDb, SearchPath) {
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(typeshed)
-            .with_python_version(python_version)
+            .with_custom_typeshed(typeshed)
+            .with_target_version(target_version)
             .build();
         let stdlib = SearchPath::custom_stdlib(&db, stdlib.parent().unwrap()).unwrap();
         (db, stdlib)

crates/red_knot_python_semantic/src/module_resolver/resolver.rs

@@ -160,7 +160,7 @@ impl SearchPaths {
         let SearchPathSettings {
             extra_paths,
             src_root,
-            typeshed,
+            custom_typeshed,
             site_packages: site_packages_paths,
         } = settings;
 
@@ -180,13 +180,17 @@ impl SearchPaths {
         tracing::debug!("Adding first-party search path '{src_root}'");
         static_paths.push(SearchPath::first_party(system, src_root.to_path_buf())?);
 
-        let (typeshed_versions, stdlib_path) = if let Some(typeshed) = typeshed {
-            let typeshed = canonicalize(typeshed, system);
-            tracing::debug!("Adding custom-stdlib search path '{typeshed}'");
+        let (typeshed_versions, stdlib_path) = if let Some(custom_typeshed) = custom_typeshed {
+            let custom_typeshed = canonicalize(custom_typeshed, system);
+            tracing::debug!("Adding custom-stdlib search path '{custom_typeshed}'");
 
-            files.try_add_root(db.upcast(), &typeshed, FileRootKind::LibrarySearchPath);
+            files.try_add_root(
+                db.upcast(),
+                &custom_typeshed,
+                FileRootKind::LibrarySearchPath,
+            );
 
-            let versions_path = typeshed.join("stdlib/VERSIONS");
+            let versions_path = custom_typeshed.join("stdlib/VERSIONS");
 
             let versions_content = system.read_to_string(&versions_path).map_err(|error| {
                 SearchPathValidationError::FailedToReadVersionsFile {
@@ -197,7 +201,7 @@ impl SearchPaths {
 
             let parsed: TypeshedVersions = versions_content.parse()?;
 
-            let search_path = SearchPath::custom_stdlib(db, &typeshed)?;
+            let search_path = SearchPath::custom_stdlib(db, &custom_typeshed)?;
 
             (parsed, search_path)
         } else {
@@ -526,10 +530,10 @@ struct ModuleNameIngredient<'db> {
 /// attempt to resolve the module name
 fn resolve_name(db: &dyn Db, name: &ModuleName) -> Option<(SearchPath, File, ModuleKind)> {
     let program = Program::get(db);
-    let python_version = program.python_version(db);
-    let resolver_state = ResolverContext::new(db, python_version);
+    let target_version = program.target_version(db);
+    let resolver_state = ResolverContext::new(db, target_version);
     let is_builtin_module =
-        ruff_python_stdlib::sys::is_builtin_module(python_version.minor, name.as_str());
+        ruff_python_stdlib::sys::is_builtin_module(target_version.minor, name.as_str());
 
     for search_path in search_paths(db) {
         // When a builtin module is imported, standard module resolution is bypassed:
@@ -686,12 +690,12 @@ impl PackageKind {
 
 pub(super) struct ResolverContext<'db> {
     pub(super) db: &'db dyn Db,
-    pub(super) python_version: PythonVersion,
+    pub(super) target_version: PythonVersion,
 }
 
 impl<'db> ResolverContext<'db> {
-    pub(super) fn new(db: &'db dyn Db, python_version: PythonVersion) -> Self {
-        Self { db, python_version }
+    pub(super) fn new(db: &'db dyn Db, target_version: PythonVersion) -> Self {
+        Self { db, target_version }
     }
 
     pub(super) fn vendored(&self) -> &VendoredFileSystem {
@@ -767,8 +771,8 @@ mod tests {
 
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
             .with_src_files(SRC)
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let builtins_module_name = ModuleName::new_static("builtins").unwrap();
@@ -785,8 +789,8 @@ mod tests {
         };
 
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
@@ -838,8 +842,8 @@ mod tests {
         };
 
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let existing_modules = create_module_names(&["asyncio", "functools", "xml.etree"]);
@@ -883,8 +887,8 @@ mod tests {
         };
 
         let TestCase { db, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let nonexisting_modules = create_module_names(&[
@@ -927,8 +931,8 @@ mod tests {
         };
 
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY39)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY39)
             .build();
 
         let existing_modules = create_module_names(&[
@@ -969,8 +973,8 @@ mod tests {
         };
 
         let TestCase { db, .. } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY39)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY39)
             .build();
 
         let nonexisting_modules = create_module_names(&["importlib", "xml", "xml.etree"]);
@@ -993,8 +997,8 @@ mod tests {
 
         let TestCase { db, src, .. } = TestCaseBuilder::new()
             .with_src_files(SRC)
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
@@ -1018,7 +1022,7 @@ mod tests {
     fn stdlib_uses_vendored_typeshed_when_no_custom_typeshed_supplied() {
         let TestCase { db, stdlib, .. } = TestCaseBuilder::new()
             .with_vendored_typeshed()
-            .with_python_version(PythonVersion::default())
+            .with_target_version(PythonVersion::default())
             .build();
 
         let pydoc_data_topics_name = ModuleName::new_static("pydoc_data.topics").unwrap();
@@ -1286,11 +1290,11 @@ mod tests {
         Program::from_settings(
             &db,
             &ProgramSettings {
-                python_version: PythonVersion::PY38,
+                target_version: PythonVersion::PY38,
                 search_paths: SearchPathSettings {
                     extra_paths: vec![],
                     src_root: src.clone(),
-                    typeshed: Some(custom_typeshed),
+                    custom_typeshed: Some(custom_typeshed),
                     site_packages: SitePackages::Known(vec![site_packages]),
                 },
             },
@@ -1329,7 +1333,7 @@ mod tests {
     fn deleting_an_unrelated_file_doesnt_change_module_resolution() {
         let TestCase { mut db, src, .. } = TestCaseBuilder::new()
             .with_src_files(&[("foo.py", "x = 1"), ("bar.py", "x = 2")])
-            .with_python_version(PythonVersion::PY38)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let foo_module_name = ModuleName::new_static("foo").unwrap();
@@ -1416,8 +1420,8 @@ mod tests {
             site_packages,
             ..
         } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
@@ -1464,8 +1468,8 @@ mod tests {
             src,
             ..
         } = TestCaseBuilder::new()
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
@@ -1504,8 +1508,8 @@ mod tests {
             ..
         } = TestCaseBuilder::new()
             .with_src_files(SRC)
-            .with_mocked_typeshed(TYPESHED)
-            .with_python_version(PythonVersion::PY38)
+            .with_custom_typeshed(TYPESHED)
+            .with_target_version(PythonVersion::PY38)
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
@@ -1791,11 +1795,11 @@ not_a_directory
         Program::from_settings(
             &db,
             &ProgramSettings {
-                python_version: PythonVersion::default(),
+                target_version: PythonVersion::default(),
                 search_paths: SearchPathSettings {
                     extra_paths: vec![],
                     src_root: SystemPathBuf::from("/src"),
-                    typeshed: None,
+                    custom_typeshed: None,
                     site_packages: SitePackages::Known(vec![
                         venv_site_packages,
                         system_site_packages,

crates/red_knot_python_semantic/src/module_resolver/testing.rs

@@ -18,7 +18,7 @@ pub(crate) struct TestCase<T> {
     // so this is a single directory instead of a `Vec` of directories,
     // like it is in `ruff_db::Program`.
     pub(crate) site_packages: SystemPathBuf,
-    pub(crate) python_version: PythonVersion,
+    pub(crate) target_version: PythonVersion,
 }
 
 /// A `(file_name, file_contents)` tuple
@@ -67,7 +67,7 @@ pub(crate) struct UnspecifiedTypeshed;
 /// ```rs
 /// let test_case = TestCaseBuilder::new()
 ///     .with_src_files(...)
-///     .with_python_version(...)
+///     .with_target_version(...)
 ///     .build();
 /// ```
 ///
@@ -85,13 +85,13 @@ pub(crate) struct UnspecifiedTypeshed;
 /// const TYPESHED = MockedTypeshed { ... };
 ///
 /// let test_case = resolver_test_case()
-///     .with_mocked_typeshed(TYPESHED)
-///     .with_python_version(...)
+///     .with_custom_typeshed(TYPESHED)
+///     .with_target_version(...)
 ///     .build();
 ///
 /// let test_case2 = resolver_test_case()
 ///     .with_vendored_typeshed()
-///     .with_python_version(...)
+///     .with_target_version(...)
 ///     .build();
 /// ```
 ///
@@ -100,7 +100,7 @@ pub(crate) struct UnspecifiedTypeshed;
 /// to `()`.
 pub(crate) struct TestCaseBuilder<T> {
     typeshed_option: T,
-    python_version: PythonVersion,
+    target_version: PythonVersion,
     first_party_files: Vec<FileSpec>,
     site_packages_files: Vec<FileSpec>,
 }
@@ -118,9 +118,9 @@ impl<T> TestCaseBuilder<T> {
         self
     }
 
-    /// Specify the Python version the module resolver should assume
-    pub(crate) fn with_python_version(mut self, python_version: PythonVersion) -> Self {
-        self.python_version = python_version;
+    /// Specify the target Python version the module resolver should assume
+    pub(crate) fn with_target_version(mut self, target_version: PythonVersion) -> Self {
+        self.target_version = target_version;
         self
     }
 
@@ -146,7 +146,7 @@ impl TestCaseBuilder<UnspecifiedTypeshed> {
     pub(crate) fn new() -> TestCaseBuilder<UnspecifiedTypeshed> {
         Self {
             typeshed_option: UnspecifiedTypeshed,
-            python_version: PythonVersion::default(),
+            target_version: PythonVersion::default(),
             first_party_files: vec![],
             site_packages_files: vec![],
         }
@@ -156,33 +156,33 @@ impl TestCaseBuilder<UnspecifiedTypeshed> {
     pub(crate) fn with_vendored_typeshed(self) -> TestCaseBuilder<VendoredTypeshed> {
         let TestCaseBuilder {
             typeshed_option: _,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         } = self;
         TestCaseBuilder {
             typeshed_option: VendoredTypeshed,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         }
     }
 
     /// Use a mock typeshed directory for this test case
-    pub(crate) fn with_mocked_typeshed(
+    pub(crate) fn with_custom_typeshed(
         self,
         typeshed: MockedTypeshed,
     ) -> TestCaseBuilder<MockedTypeshed> {
         let TestCaseBuilder {
             typeshed_option: _,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         } = self;
 
         TestCaseBuilder {
             typeshed_option: typeshed,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         }
@@ -194,15 +194,15 @@ impl TestCaseBuilder<UnspecifiedTypeshed> {
             src,
             stdlib: _,
             site_packages,
-            python_version,
-        } = self.with_mocked_typeshed(MockedTypeshed::default()).build();
+            target_version,
+        } = self.with_custom_typeshed(MockedTypeshed::default()).build();
 
         TestCase {
             db,
             src,
             stdlib: (),
             site_packages,
-            python_version,
+            target_version,
         }
     }
 }
@@ -211,7 +211,7 @@ impl TestCaseBuilder<MockedTypeshed> {
     pub(crate) fn build(self) -> TestCase<SystemPathBuf> {
         let TestCaseBuilder {
             typeshed_option,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         } = self;
@@ -226,11 +226,11 @@ impl TestCaseBuilder<MockedTypeshed> {
         Program::from_settings(
             &db,
             &ProgramSettings {
-                python_version,
+                target_version,
                 search_paths: SearchPathSettings {
                     extra_paths: vec![],
                     src_root: src.clone(),
-                    typeshed: Some(typeshed.clone()),
+                    custom_typeshed: Some(typeshed.clone()),
                     site_packages: SitePackages::Known(vec![site_packages.clone()]),
                 },
             },
@@ -242,7 +242,7 @@ impl TestCaseBuilder<MockedTypeshed> {
             src,
             stdlib: typeshed.join("stdlib"),
             site_packages,
-            python_version,
+            target_version,
         }
     }
 
@@ -268,7 +268,7 @@ impl TestCaseBuilder<VendoredTypeshed> {
     pub(crate) fn build(self) -> TestCase<VendoredPathBuf> {
         let TestCaseBuilder {
             typeshed_option: VendoredTypeshed,
-            python_version,
+            target_version,
             first_party_files,
             site_packages_files,
         } = self;
@@ -282,7 +282,7 @@ impl TestCaseBuilder<VendoredTypeshed> {
         Program::from_settings(
             &db,
             &ProgramSettings {
-                python_version,
+                target_version,
                 search_paths: SearchPathSettings {
                     site_packages: SitePackages::Known(vec![site_packages.clone()]),
                     ..SearchPathSettings::new(src.clone())
@@ -296,7 +296,7 @@ impl TestCaseBuilder<VendoredTypeshed> {
             src,
             stdlib: VendoredPathBuf::from("stdlib"),
             site_packages,
-            python_version,
+            target_version,
         }
     }
 }

crates/red_knot_python_semantic/src/module_resolver/typeshed.rs

@@ -112,10 +112,10 @@ impl TypeshedVersions {
     pub(in crate::module_resolver) fn query_module(
         &self,
         module: &ModuleName,
-        python_version: PythonVersion,
+        target_version: PythonVersion,
     ) -> TypeshedVersionsQueryResult {
         if let Some(range) = self.exact(module) {
-            if range.contains(python_version) {
+            if range.contains(target_version) {
                 TypeshedVersionsQueryResult::Exists
             } else {
                 TypeshedVersionsQueryResult::DoesNotExist
@@ -125,7 +125,7 @@ impl TypeshedVersions {
             while let Some(module_to_try) = module {
                 if let Some(range) = self.exact(&module_to_try) {
                     return {
-                        if range.contains(python_version) {
+                        if range.contains(target_version) {
                             TypeshedVersionsQueryResult::MaybeExists
                         } else {
                             TypeshedVersionsQueryResult::DoesNotExist

crates/red_knot_python_semantic/src/program.rs

@@ -10,7 +10,7 @@ use crate::Db;
 
 #[salsa::input(singleton)]
 pub struct Program {
-    pub python_version: PythonVersion,
+    pub target_version: PythonVersion,
 
     #[return_ref]
     pub(crate) search_paths: SearchPaths,
@@ -19,16 +19,16 @@ pub struct Program {
 impl Program {
     pub fn from_settings(db: &dyn Db, settings: &ProgramSettings) -> anyhow::Result<Self> {
         let ProgramSettings {
-            python_version,
+            target_version,
             search_paths,
         } = settings;
 
-        tracing::info!("Python version: Python {python_version}");
+        tracing::info!("Target version: Python {target_version}");
 
         let search_paths = SearchPaths::from_settings(db, search_paths)
             .with_context(|| "Invalid search path settings")?;
 
-        Ok(Program::builder(settings.python_version, search_paths)
+        Ok(Program::builder(settings.target_version, search_paths)
             .durability(Durability::HIGH)
             .new(db))
     }
@@ -56,7 +56,7 @@ impl Program {
 #[derive(Clone, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct ProgramSettings {
-    pub python_version: PythonVersion,
+    pub target_version: PythonVersion,
     pub search_paths: SearchPathSettings,
 }
 
@@ -75,7 +75,7 @@ pub struct SearchPathSettings {
     /// Optional path to a "custom typeshed" directory on disk for us to use for standard-library types.
     /// If this is not provided, we will fallback to our vendored typeshed stubs for the stdlib,
     /// bundled as a zip file in the binary
-    pub typeshed: Option<SystemPathBuf>,
+    pub custom_typeshed: Option<SystemPathBuf>,
 
     /// The path to the user's `site-packages` directory, where third-party packages from ``PyPI`` are installed.
     pub site_packages: SitePackages,
@@ -86,7 +86,7 @@ impl SearchPathSettings {
         Self {
             src_root,
             extra_paths: vec![],
-            typeshed: None,
+            custom_typeshed: None,
             site_packages: SitePackages::Known(vec![]),
         }
     }

crates/red_knot_python_semantic/src/python_version.rs

@@ -5,6 +5,7 @@ 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,
@@ -67,42 +68,3 @@ impl fmt::Display for PythonVersion {
         write!(f, "{major}.{minor}")
     }
 }
-
-#[cfg(feature = "serde")]
-impl<'de> serde::Deserialize<'de> for PythonVersion {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let as_str = String::deserialize(deserializer)?;
-
-        if let Some((major, minor)) = as_str.split_once('.') {
-            let major = major
-                .parse()
-                .map_err(|err| serde::de::Error::custom(format!("invalid major version: {err}")))?;
-            let minor = minor
-                .parse()
-                .map_err(|err| serde::de::Error::custom(format!("invalid minor version: {err}")))?;
-
-            Ok((major, minor).into())
-        } else {
-            let major = as_str.parse().map_err(|err| {
-                serde::de::Error::custom(format!(
-                    "invalid python-version: {err}, expected: `major.minor`"
-                ))
-            })?;
-
-            Ok((major, 0).into())
-        }
-    }
-}
-
-#[cfg(feature = "serde")]
-impl serde::Serialize for PythonVersion {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        serializer.serialize_str(&self.to_string())
-    }
-}

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -1,13 +1,10 @@
-use std::num::NonZeroUsize;
-use std::ops::Div;
 use std::sync::Arc;
 
 use except_handlers::TryNodeContextStackManager;
-use rustc_hash::{FxBuildHasher, FxHashMap};
+use rustc_hash::FxHashMap;
 
 use ruff_db::files::File;
 use ruff_db::parsed::ParsedModule;
-use ruff_db::source::source_text;
 use ruff_index::IndexVec;
 use ruff_python_ast as ast;
 use ruff_python_ast::name::Name;
@@ -86,10 +83,6 @@ pub(super) struct SemanticIndexBuilder<'db> {
 
 impl<'db> SemanticIndexBuilder<'db> {
     pub(super) fn new(db: &'db dyn Db, file: File, parsed: &'db ParsedModule) -> Self {
-        let source = source_text(db.upcast(), file);
-        let approximated_expressions = (source.len() as f64 * 0.05) as usize;
-        let approximated_definitions = (source.len() as f64 * 0.015) as usize;
-
         let mut builder = Self {
             db,
             file,
@@ -108,19 +101,10 @@ impl<'db> SemanticIndexBuilder<'db> {
             scope_ids_by_scope: IndexVec::new(),
             use_def_maps: IndexVec::new(),
 
-            scopes_by_expression: FxHashMap::with_capacity_and_hasher(
-                approximated_expressions,
-                FxBuildHasher::default(),
-            ),
+            scopes_by_expression: FxHashMap::default(),
             scopes_by_node: FxHashMap::default(),
-            definitions_by_node: FxHashMap::with_capacity_and_hasher(
-                approximated_definitions,
-                FxBuildHasher::default(),
-            ),
-            expressions_by_node: FxHashMap::with_capacity_and_hasher(
-                approximated_expressions,
-                FxBuildHasher::default(),
-            ),
+            definitions_by_node: FxHashMap::default(),
+            expressions_by_node: FxHashMap::default(),
         };
 
         builder.push_scope_with_parent(NodeWithScopeRef::Module, None);
@@ -564,19 +548,6 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.scope_ids_by_scope.shrink_to_fit();
         self.scopes_by_node.shrink_to_fit();
 
-        // let source_len = source_text(self.db.upcast(), self.file).len();
-        // let expressions = self.scopes_by_expression.len();
-        // let definitions = self.definitions_by_node.len();
-        //
-        // let expression_rel = NonZeroUsize::new(source_len)
-        //     .map(|size| (expressions as f64).div(size.get() as f64))
-        //     .unwrap_or_default();
-        // let definitions_rel = NonZeroUsize::new(source_len)
-        //     .map(|size| (definitions as f64).div(size.get() as f64))
-        //     .unwrap_or_default();
-        //
-        // println!("{source_len},{expressions},{expression_rel},{definitions},{definitions_rel}");
-
         SemanticIndex {
             symbol_tables,
             scopes: self.scopes,
@@ -862,7 +833,6 @@ where
                 self.visit_expr(test);
 
                 let pre_loop = self.flow_snapshot();
-                let constraint = self.record_expression_constraint(test);
 
                 // Save aside any break states from an outer loop
                 let saved_break_states = std::mem::take(&mut self.loop_break_states);
@@ -882,7 +852,6 @@ where
                 // We may execute the `else` clause without ever executing the body, so merge in
                 // the pre-loop state before visiting `else`.
                 self.flow_merge(pre_loop);
-                self.record_negated_constraint(constraint);
                 self.visit_body(orelse);
 
                 // Breaking out of a while loop bypasses the `else` clause, so merge in the break

crates/red_knot_python_semantic/src/semantic_index/definition.rs

@@ -1,7 +1,6 @@
 use ruff_db::files::File;
 use ruff_db::parsed::ParsedModule;
 use ruff_python_ast as ast;
-use ruff_text_size::{Ranged, TextRange};
 
 use crate::ast_node_ref::AstNodeRef;
 use crate::module_resolver::file_to_module;
@@ -466,33 +465,6 @@ pub enum DefinitionKind<'db> {
     TypeVarTuple(AstNodeRef<ast::TypeParamTypeVarTuple>),
 }
 
-impl Ranged for DefinitionKind<'_> {
-    fn range(&self) -> TextRange {
-        match self {
-            DefinitionKind::Import(alias) => alias.range(),
-            DefinitionKind::ImportFrom(import) => import.alias().range(),
-            DefinitionKind::Function(function) => function.name.range(),
-            DefinitionKind::Class(class) => class.name.range(),
-            DefinitionKind::TypeAlias(type_alias) => type_alias.name.range(),
-            DefinitionKind::NamedExpression(named) => named.target.range(),
-            DefinitionKind::Assignment(assignment) => assignment.name().range(),
-            DefinitionKind::AnnotatedAssignment(assign) => assign.target.range(),
-            DefinitionKind::AugmentedAssignment(aug_assign) => aug_assign.target.range(),
-            DefinitionKind::For(for_stmt) => for_stmt.target().range(),
-            DefinitionKind::Comprehension(comp) => comp.target().range(),
-            DefinitionKind::VariadicPositionalParameter(parameter) => parameter.name.range(),
-            DefinitionKind::VariadicKeywordParameter(parameter) => parameter.name.range(),
-            DefinitionKind::Parameter(parameter) => parameter.parameter.name.range(),
-            DefinitionKind::WithItem(with_item) => with_item.target().range(),
-            DefinitionKind::MatchPattern(match_pattern) => match_pattern.identifier.range(),
-            DefinitionKind::ExceptHandler(handler) => handler.node().range(),
-            DefinitionKind::TypeVar(type_var) => type_var.name.range(),
-            DefinitionKind::ParamSpec(param_spec) => param_spec.name.range(),
-            DefinitionKind::TypeVarTuple(type_var_tuple) => type_var_tuple.name.range(),
-        }
-    }
-}
-
 impl DefinitionKind<'_> {
     pub(crate) fn category(&self) -> DefinitionCategory {
         match self {

crates/red_knot_python_semantic/src/semantic_index/use_def.rs

@@ -47,7 +47,7 @@
 //! The **declared type** represents the code author's declaration (usually through a type
 //! annotation) that a given variable should not be assigned any type outside the declared type. In
 //! our model, declared types are also control-flow-sensitive; we allow the code author to
-//! explicitly redeclare the same variable with a different type. So for a given binding of a
+//! explicitly re-declare the same variable with a different type. So for a given binding of a
 //! variable, we will want to ask which declarations of that variable can reach that binding, in
 //! order to determine whether the binding is permitted, or should be a type error. For example:
 //!
@@ -62,7 +62,7 @@
 //! assignable to `str`. This is the purpose of declared types: they prevent accidental assignment
 //! of the wrong type to a variable.
 //!
-//! But in some cases it is useful to "shadow" or "redeclare" a variable with a new type, and we
+//! But in some cases it is useful to "shadow" or "re-declare" a variable with a new type, and we
 //! permit this, as long as it is done with an explicit re-annotation. So `path: Path =
 //! Path(path)`, with the explicit `: Path` annotation, is permitted.
 //!