Merge branch 'main' into dcreager/function-enum

* main:
  Update pre-commit dependencies (#17506)
  [red-knot] Simplify visibility constraint handling for `*`-import definitions (#17486)
  [red-knot] Detect (some) invalid protocols (#17488)
  [red-knot] Correctly identify protocol classes (#17487)
  Update dependency ruff to v0.11.6 (#17516)
  Update Rust crate shellexpand to v3.1.1 (#17512)
  Update Rust crate proc-macro2 to v1.0.95 (#17510)
  Update Rust crate rand to v0.9.1 (#17511)
  Update Rust crate libc to v0.2.172 (#17509)
  Update Rust crate jiff to v0.2.9 (#17508)
  Update Rust crate clap to v4.5.37 (#17507)
  Update astral-sh/setup-uv action to v5.4.2 (#17504)
  Update taiki-e/install-action digest to 09dc018 (#17503)
  [red-knot] infer attribute assignments bound in comprehensions (#17396)
  [red-knot] simplify gradually-equivalent types out of unions and intersections (#17467)
  [red-knot] pull primer projects to run from file (#17473)

.github/workflows/build-binaries.yml

@@ -49,7 +49,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build sdist"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           command: sdist
           args: --out dist
@@ -79,7 +79,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels - x86_64"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: x86_64
           args: --release --locked --out dist
@@ -121,7 +121,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels - aarch64"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: aarch64
           args: --release --locked --out dist
@@ -177,7 +177,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: ${{ matrix.platform.target }}
           args: --release --locked --out dist
@@ -230,7 +230,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: ${{ matrix.target }}
           manylinux: auto
@@ -304,7 +304,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: ${{ matrix.platform.target }}
           manylinux: auto
@@ -370,14 +370,14 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: ${{ matrix.target }}
           manylinux: musllinux_1_2
           args: --release --locked --out dist
       - name: "Test wheel"
         if: matrix.target == 'x86_64-unknown-linux-musl'
-        uses: addnab/docker-run-action@v3
+        uses: addnab/docker-run-action@4f65fabd2431ebc8d299f8e5a018d79a769ae185 # v3
         with:
           image: alpine:latest
           options: -v ${{ github.workspace }}:/io -w /io
@@ -435,7 +435,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           target: ${{ matrix.platform.target }}
           manylinux: musllinux_1_2

.github/workflows/ci.yaml

@@ -237,13 +237,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-insta
       - name: Red-knot mdtests (GitHub annotations)
@@ -291,13 +291,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-insta
       - name: "Run tests"
@@ -320,7 +320,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-nextest
       - name: "Run tests"
@@ -376,7 +376,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - name: "Build"
         run: cargo build --release --locked
 
@@ -401,13 +401,13 @@ jobs:
           MSRV: ${{ steps.msrv.outputs.value }}
         run: rustup default "${MSRV}"
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-insta
       - name: "Run tests"
@@ -433,7 +433,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo-binstall"
-        uses: cargo-bins/cargo-binstall@main
+        uses: cargo-bins/cargo-binstall@63aaa5c1932cebabc34eceda9d92a70215dcead6 # v1.12.3
         with:
           tool: cargo-fuzz@0.11.2
       - name: "Install cargo-fuzz"
@@ -455,7 +455,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+      - uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
       - uses: actions/download-artifact@95815c38cf2ff2164869cbab79da8d1f422bc89e # v4.2.1
         name: Download Ruff binary to test
         id: download-cached-binary
@@ -641,7 +641,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: cargo-bins/cargo-binstall@main
+      - uses: cargo-bins/cargo-binstall@63aaa5c1932cebabc34eceda9d92a70215dcead6 # v1.12.3
       - run: cargo binstall --no-confirm cargo-shear
       - run: cargo shear
 
@@ -662,7 +662,7 @@ jobs:
       - name: "Prep README.md"
         run: python scripts/transform_readme.py --target pypi
       - name: "Build wheels"
-        uses: PyO3/maturin-action@44479ae1b6b1a57f561e03add8832e62c185eb17 # v1.48.1
+        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
         with:
           args: --out dist
       - name: "Test wheel"
@@ -681,7 +681,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+      - uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
       - name: "Cache pre-commit"
         uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
         with:
@@ -720,7 +720,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: Install uv
-        uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+        uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
       - name: "Install Insiders dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
         run: uv pip install -r docs/requirements-insiders.txt --system
@@ -857,7 +857,7 @@ jobs:
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@d4635f2de61c8b8104d59cd4aede2060638378cc # v2
+        uses: taiki-e/install-action@09dc018eee06ae1c9e0409786563f534210ceb83 # v2
         with:
           tool: cargo-codspeed
 

.github/workflows/daily_fuzz.yaml

@@ -34,11 +34,11 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+      - uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
       - name: Build ruff
         # A debug build means the script runs slower once it gets started,

.github/workflows/daily_property_tests.yaml

@@ -36,7 +36,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@v1
+        uses: rui314/setup-mold@e16410e7f8d9e167b74ad5697a9089a35126eb50 # v1
       - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
       - name: Build Red Knot
         # A release build takes longer (2 min vs 1 min), but the property tests run much faster in release

.github/workflows/mypy_primer.yaml

@@ -35,7 +35,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+        uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
 
       - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
         with:
@@ -45,13 +45,15 @@ jobs:
 
       - name: Install mypy_primer
         run: |
-          uv tool install "git+https://github.com/astral-sh/mypy_primer.git@add-red-knot-support-v4"
+          uv tool install "git+https://github.com/astral-sh/mypy_primer.git@add-red-knot-support-v5"
 
       - name: Run mypy_primer
         shell: bash
         run: |
           cd ruff
 
+          PRIMER_SELECTOR="$(paste -s -d'|' crates/red_knot_python_semantic/resources/primer/good.txt)"
+
           echo "new commit"
           git rev-list --format=%s --max-count=1 "$GITHUB_SHA"
 
@@ -62,13 +64,14 @@ jobs:
 
           cd ..
 
+          echo "Project selector: $PRIMER_SELECTOR"
           # Allow the exit code to be 0 or 1, only fail for actual mypy_primer crashes/bugs
           uvx mypy_primer \
             --repo ruff \
             --type-checker knot \
             --old base_commit \
             --new "$GITHUB_SHA" \
-            --project-selector '/(mypy_primer|black|pyp|git-revise|zipp|arrow|isort|itsdangerous|rich|packaging|pybind11|pyinstrument|typeshed-stats|scrapy|werkzeug|bidict|async-utils)$' \
+            --project-selector "/($PRIMER_SELECTOR)\$" \
             --output concise \
             --debug > mypy_primer.diff || [ $? -eq 1 ]
 

.github/workflows/publish-pypi.yml

@@ -22,7 +22,7 @@ jobs:
       id-token: write
     steps:
       - name: "Install uv"
-        uses: astral-sh/setup-uv@0c5e2b8115b80b4c7c5ddf6ffdd634974642d182 # v5.4.1
+        uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
       - uses: actions/download-artifact@95815c38cf2ff2164869cbab79da8d1f422bc89e # v4.2.1
         with:
           pattern: wheels-*

.pre-commit-config.yaml

@@ -79,7 +79,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.11.4
+    rev: v0.11.6
     hooks:
       - id: ruff-format
       - id: ruff
@@ -97,12 +97,12 @@ repos:
   # zizmor detects security vulnerabilities in GitHub Actions workflows.
   # Additional configuration for the tool is found in `.github/zizmor.yml`
   - repo: https://github.com/woodruffw/zizmor-pre-commit
-    rev: v1.5.2
+    rev: v1.6.0
     hooks:
       - id: zizmor
 
   - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.32.1
+    rev: 0.33.0
     hooks:
       - id: check-github-workflows
 

CHANGELOG.md

@@ -1,5 +1,16 @@
 # Changelog
 
+## 0.11.6
+
+### Preview features
+
+- Avoid adding whitespace to the end of a docstring after an escaped quote ([#17216](https://github.com/astral-sh/ruff/pull/17216))
+- \[`airflow`\] Extract `AIR311` from `AIR301` rules (`AIR301`, `AIR311`) ([#17310](https://github.com/astral-sh/ruff/pull/17310), [#17422](https://github.com/astral-sh/ruff/pull/17422))
+
+### Bug fixes
+
+- Raise syntax error when `\` is at end of file ([#17409](https://github.com/astral-sh/ruff/pull/17409))
+
 ## 0.11.5
 
 ### Preview features

Cargo.lock

@@ -128,9 +128,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.97"
+version = "1.0.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcfed56ad506cb2c684a14971b8861fdc3baaaae314b9e5f9bb532cbe3ba7a4f"
+checksum = "e16d2d3311acee920a9eb8d33b8cbc1787ce4a264e85f964c2404b969bdcd487"
 
 [[package]]
 name = "argfile"
@@ -216,9 +216,9 @@ dependencies = [
 
 [[package]]
 name = "bstr"
-version = "1.11.3"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "531a9155a481e2ee699d4f98f43c0ca4ff8ee1bfd55c31e9e98fb29d2b176fe0"
+checksum = "234113d19d0d7d613b40e86fb654acf958910802bcceab913a4f9e7cda03b1a4"
 dependencies = [
  "memchr",
  "regex-automata 0.4.9",
@@ -334,9 +334,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.5.35"
+version = "4.5.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d8aa86934b44c19c50f87cc2790e19f54f7a67aedb64101c2e1a2e5ecfb73944"
+checksum = "eccb054f56cbd38340b380d4a8e69ef1f02f1af43db2f0cc817a4774d80ae071"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -344,9 +344,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.35"
+version = "4.5.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2414dbb2dd0695280da6ea9261e327479e9d37b0630f6b53ba2a11c60c679fd9"
+checksum = "efd9466fac8543255d3b1fcad4762c5e116ffe808c8a3043d4263cd4fd4862a2"
 dependencies = [
  "anstream",
  "anstyle",
@@ -478,7 +478,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
 dependencies = [
  "lazy_static",
- "windows-sys 0.48.0",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -487,7 +487,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fde0e0ec90c9dfb3b4b1a0891a7dcd0e2bffde2f7efed5fe7c9bb00e5bfb915e"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]
@@ -1553,28 +1553,45 @@ checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
 
 [[package]]
 name = "jiff"
-version = "0.2.4"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d699bc6dfc879fb1bf9bdff0d4c56f0884fc6f0d0eb0fba397a6d00cd9a6b85e"
+checksum = "59ec30f7142be6fe14e1b021f50b85db8df2d4324ea6e91ec3e5dcde092021d0"
 dependencies = [
  "jiff-static",
+ "jiff-tzdb-platform",
  "log",
  "portable-atomic",
  "portable-atomic-util",
  "serde",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
 name = "jiff-static"
-version = "0.2.4"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d16e75759ee0aa64c57a56acbf43916987b20c77373cb7e808979e02b93c9f9"
+checksum = "526b834d727fd59d37b076b0c3236d9adde1b1729a4361e20b2026f738cc1dbe"
 dependencies = [
  "proc-macro2",
  "quote",
  "syn 2.0.100",
 ]
 
+[[package]]
+name = "jiff-tzdb"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1283705eb0a21404d2bfd6eef2a7593d240bc42a0bdb39db0ad6fa2ec026524"
+
+[[package]]
+name = "jiff-tzdb-platform"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "875a5a69ac2bab1a891711cf5eccbec1ce0341ea805560dcd90b7a2e925132e8"
+dependencies = [
+ "jiff-tzdb",
+]
+
 [[package]]
 name = "jobserver"
 version = "0.1.32"
@@ -1628,9 +1645,9 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
 [[package]]
 name = "libc"
-version = "0.2.171"
+version = "0.2.172"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c19937216e9d3aa9956d9bb8dfc0b0c8beb6058fc4f7a4dc4d850edf86a237d6"
+checksum = "d750af042f7ef4f724306de029d18836c26c1765a54a6a3f094cbd23a7267ffa"
 
 [[package]]
 name = "libcst"
@@ -1659,9 +1676,9 @@ dependencies = [
 
 [[package]]
 name = "libmimalloc-sys"
-version = "0.1.41"
+version = "0.1.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b20daca3a4ac14dbdc753c5e90fc7b490a48a9131daed3c9a9ced7b2defd37b"
+checksum = "ec9d6fac27761dabcd4ee73571cdb06b7022dc99089acbe5435691edffaac0f4"
 dependencies = [
  "cc",
  "libc",
@@ -1797,9 +1814,9 @@ checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
 [[package]]
 name = "mimalloc"
-version = "0.1.45"
+version = "0.1.46"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "03cb1f88093fe50061ca1195d336ffec131347c7b833db31f9ab62a2d1b7925f"
+checksum = "995942f432bbb4822a7e9c3faa87a695185b0d09273ba85f097b54f4e458f2af"
 dependencies = [
  "libmimalloc-sys",
 ]
@@ -2310,9 +2327,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.94"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a31971752e70b8b2686d7e46ec17fb38dad4051d94024c88df49b667caea9c84"
+checksum = "02b3e5e68a3a1a02aad3ec490a98007cbc13c37cbe84a3cd7b8e406d76e7f778"
 dependencies = [
  "unicode-ident",
 ]
@@ -2403,13 +2420,12 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.9.0"
+version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3779b94aeb87e8bd4e834cee3650289ee9e0d5677f976ecdb6d219e5f4f6cd94"
+checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
 dependencies = [
  "rand_chacha 0.9.0",
  "rand_core 0.9.3",
- "zerocopy",
 ]
 
 [[package]]
@@ -2476,7 +2492,6 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "argfile",
- "chrono",
  "clap",
  "colored 3.0.0",
  "countme",
@@ -2485,6 +2500,7 @@ dependencies = [
  "filetime",
  "insta",
  "insta-cmd",
+ "jiff",
  "rayon",
  "red_knot_project",
  "red_knot_python_semantic",
@@ -2756,7 +2772,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.11.5"
+version = "0.11.6"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2764,7 +2780,6 @@ dependencies = [
  "bincode",
  "bitflags 2.9.0",
  "cachedir",
- "chrono",
  "clap",
  "clap_complete_command",
  "clearscreen",
@@ -2777,6 +2792,7 @@ dependencies = [
  "insta-cmd",
  "is-macro",
  "itertools 0.14.0",
+ "jiff",
  "log",
  "mimalloc",
  "notify",
@@ -2991,12 +3007,11 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.11.5"
+version = "0.11.6"
 dependencies = [
  "aho-corasick",
  "anyhow",
  "bitflags 2.9.0",
- "chrono",
  "clap",
  "colored 3.0.0",
  "fern",
@@ -3007,6 +3022,7 @@ dependencies = [
  "is-macro",
  "is-wsl",
  "itertools 0.14.0",
+ "jiff",
  "libcst",
  "log",
  "memchr",
@@ -3067,7 +3083,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "itertools 0.14.0",
- "rand 0.9.0",
+ "rand 0.9.1",
  "ruff_diagnostics",
  "ruff_source_file",
  "ruff_text_size",
@@ -3317,7 +3333,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.11.5"
+version = "0.11.6"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3658,9 +3674,9 @@ dependencies = [
 
 [[package]]
 name = "shellexpand"
-version = "3.1.0"
+version = "3.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da03fa3b94cc19e3ebfc88c4229c49d8f08cdbd1228870a45f0ffdf84988e14b"
+checksum = "8b1fdf65dd6331831494dd616b30351c38e96e45921a27745cf98490458b90bb"
 dependencies = [
  "dirs",
 ]
@@ -4311,7 +4327,7 @@ checksum = "458f7a779bf54acc9f347480ac654f68407d3aab21269a6e3c9f922acd9e2da9"
 dependencies = [
  "getrandom 0.3.2",
  "js-sys",
- "rand 0.9.0",
+ "rand 0.9.1",
  "uuid-macro-internal",
  "wasm-bindgen",
 ]
@@ -4582,7 +4598,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.48.0",
+ "windows-sys 0.52.0",
 ]
 
 [[package]]

Cargo.toml

@@ -55,7 +55,6 @@ bitflags = { version = "2.5.0" }
 bstr = { version = "1.9.1" }
 cachedir = { version = "0.3.1" }
 camino = { version = "1.1.7" }
-chrono = { version = "0.4.35", default-features = false, features = ["clock"] }
 clap = { version = "4.5.3", features = ["derive"] }
 clap_complete_command = { version = "0.6.0" }
 clearscreen = { version = "4.0.0" }
@@ -95,6 +94,7 @@ insta-cmd = { version = "0.6.0" }
 is-macro = { version = "0.3.5" }
 is-wsl = { version = "0.4.0" }
 itertools = { version = "0.14.0" }
+jiff = { version = "0.2.0" }
 js-sys = { version = "0.3.69" }
 jod-thread = { version = "0.1.2" }
 libc = { version = "0.2.153" }

README.md

@@ -149,8 +149,8 @@ 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/0.11.5/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.11.5/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.11.6/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.11.6/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -183,7 +183,7 @@ 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: v0.11.5
+  rev: v0.11.6
   hooks:
     # Run the linter.
     - id: ruff

crates/red_knot/Cargo.toml

@@ -20,12 +20,12 @@ ruff_python_ast = { workspace = true }
 
 anyhow = { workspace = true }
 argfile = { workspace = true }
-chrono = { workspace = true }
 clap = { workspace = true, features = ["wrap_help"] }
 colored = { workspace = true }
 countme = { workspace = true, features = ["enable"] }
 crossbeam = { workspace = true }
 ctrlc = { version = "3.4.4" }
+jiff = { workspace = true }
 rayon = { workspace = true }
 salsa = { workspace = true }
 tracing = { workspace = true, features = ["release_max_level_debug"] }

crates/red_knot/docs/mypy_primer.md

@@ -31,7 +31,7 @@ mypy_primer \
 ```
 
 This will show the diagnostics diff for the `black` project between the `main` branch and your `my/feature` branch. To run the
-diff for all projects, you currently need to copy the project-selector regex from the CI pipeline in `.github/workflows/mypy_primer.yaml`.
+diff for all projects we currently enable in CI, use `--project-selector "/($(paste -s -d'|' crates/red_knot_python_semantic/resources/primer/good.txt))\$"`.
 
 You can also take a look at the [full list of ecosystem projects]. Note that some of them might still need a `knot_paths` configuration
 option to work correctly.

crates/red_knot/src/logging.rs

@@ -190,8 +190,8 @@ where
         let ansi = writer.has_ansi_escapes();
 
         if self.display_timestamp {
-            let timestamp = chrono::Local::now()
-                .format("%Y-%m-%d %H:%M:%S.%f")
+            let timestamp = jiff::Zoned::now()
+                .strftime("%Y-%m-%d %H:%M:%S.%f")
                 .to_string();
             if ansi {
                 write!(writer, "{} ", timestamp.dimmed())?;
@@ -199,7 +199,7 @@ where
                 write!(
                     writer,
                     "{} ",
-                    chrono::Local::now().format("%Y-%m-%d %H:%M:%S.%f")
+                    jiff::Zoned::now().strftime("%Y-%m-%d %H:%M:%S.%f")
                 )?;
             }
         }

crates/red_knot/tests/cli.rs

@@ -83,13 +83,13 @@ fn config_override_python_platform() -> anyhow::Result<()> {
     success: true
     exit_code: 0
     ----- stdout -----
-    info: revealed-type
+    info: revealed-type: Revealed type
      --> <temp_dir>/test.py:5:1
       |
     3 | from typing_extensions import reveal_type
     4 |
     5 | reveal_type(sys.platform)
-      | ^^^^^^^^^^^^^^^^^^^^^^^^^ Revealed type is `Literal["linux"]`
+      | ^^^^^^^^^^^^^^^^^^^^^^^^^ `Literal["linux"]`
       |
 
     Found 1 diagnostic
@@ -101,13 +101,13 @@ fn config_override_python_platform() -> anyhow::Result<()> {
     success: true
     exit_code: 0
     ----- stdout -----
-    info: revealed-type
+    info: revealed-type: Revealed type
      --> <temp_dir>/test.py:5:1
       |
     3 | from typing_extensions import reveal_type
     4 |
     5 | reveal_type(sys.platform)
-      | ^^^^^^^^^^^^^^^^^^^^^^^^^ Revealed type is `LiteralString`
+      | ^^^^^^^^^^^^^^^^^^^^^^^^^ `LiteralString`
       |
 
     Found 1 diagnostic
@@ -252,7 +252,7 @@ fn configuration_rule_severity() -> anyhow::Result<()> {
         r#"
             y = 4 / 0
 
-            for a in range(0, y):
+            for a in range(0, int(y)):
                 x = a
 
             print(x)  # possibly-unresolved-reference
@@ -271,7 +271,7 @@ fn configuration_rule_severity() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     warning: lint:possibly-unresolved-reference
@@ -307,7 +307,7 @@ fn configuration_rule_severity() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     Found 1 diagnostic
@@ -328,7 +328,7 @@ fn cli_rule_severity() -> anyhow::Result<()> {
 
         y = 4 / 0
 
-        for a in range(0, y):
+        for a in range(0, int(y)):
             x = a
 
         print(x)  # possibly-unresolved-reference
@@ -358,7 +358,7 @@ fn cli_rule_severity() -> anyhow::Result<()> {
     4 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     5 |
-    6 | for a in range(0, y):
+    6 | for a in range(0, int(y)):
       |
 
     warning: lint:possibly-unresolved-reference
@@ -405,7 +405,7 @@ fn cli_rule_severity() -> anyhow::Result<()> {
     4 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     5 |
-    6 | for a in range(0, y):
+    6 | for a in range(0, int(y)):
       |
 
     Found 2 diagnostics
@@ -426,7 +426,7 @@ fn cli_rule_severity_precedence() -> anyhow::Result<()> {
         r#"
         y = 4 / 0
 
-        for a in range(0, y):
+        for a in range(0, int(y)):
             x = a
 
         print(x)  # possibly-unresolved-reference
@@ -445,7 +445,7 @@ fn cli_rule_severity_precedence() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     warning: lint:possibly-unresolved-reference
@@ -482,7 +482,7 @@ fn cli_rule_severity_precedence() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     Found 1 diagnostic
@@ -584,12 +584,12 @@ fn exit_code_only_info() -> anyhow::Result<()> {
     success: true
     exit_code: 0
     ----- stdout -----
-    info: revealed-type
+    info: revealed-type: Revealed type
      --> <temp_dir>/test.py:3:1
       |
     2 | from typing_extensions import reveal_type
     3 | reveal_type(1)
-      | ^^^^^^^^^^^^^^ Revealed type is `Literal[1]`
+      | ^^^^^^^^^^^^^^ `Literal[1]`
       |
 
     Found 1 diagnostic
@@ -614,12 +614,12 @@ fn exit_code_only_info_and_error_on_warning_is_true() -> anyhow::Result<()> {
     success: true
     exit_code: 0
     ----- stdout -----
-    info: revealed-type
+    info: revealed-type: Revealed type
      --> <temp_dir>/test.py:3:1
       |
     2 | from typing_extensions import reveal_type
     3 | reveal_type(1)
-      | ^^^^^^^^^^^^^^ Revealed type is `Literal[1]`
+      | ^^^^^^^^^^^^^^ `Literal[1]`
       |
 
     Found 1 diagnostic
@@ -814,7 +814,7 @@ fn user_configuration() -> anyhow::Result<()> {
             r#"
             y = 4 / 0
 
-            for a in range(0, y):
+            for a in range(0, int(y)):
                 x = a
 
             print(x)
@@ -841,7 +841,7 @@ fn user_configuration() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     warning: lint:possibly-unresolved-reference
@@ -883,7 +883,7 @@ fn user_configuration() -> anyhow::Result<()> {
     2 | y = 4 / 0
       |     ^^^^^ Cannot divide object of type `Literal[4]` by zero
     3 |
-    4 | for a in range(0, y):
+    4 | for a in range(0, int(y)):
       |
 
     error: lint:possibly-unresolved-reference
@@ -1052,6 +1052,39 @@ fn concise_diagnostics() -> anyhow::Result<()> {
     Ok(())
 }
 
+/// This tests the diagnostic format for revealed type.
+///
+/// This test was introduced because changes were made to
+/// how the revealed type diagnostic was constructed and
+/// formatted in "verbose" mode. But it required extra
+/// logic to ensure the concise version didn't regress on
+/// information content. So this test was introduced to
+/// capture that.
+#[test]
+fn concise_revealed_type() -> anyhow::Result<()> {
+    let case = TestCase::with_file(
+        "test.py",
+        r#"
+        from typing_extensions import reveal_type
+
+        x = "hello"
+        reveal_type(x)
+        "#,
+    )?;
+
+    assert_cmd_snapshot!(case.command().arg("--output-format=concise"), @r#"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    info[revealed-type] <temp_dir>/test.py:5:1: Revealed type: `Literal["hello"]`
+    Found 1 diagnostic
+
+    ----- stderr -----
+    "#);
+
+    Ok(())
+}
+
 struct TestCase {
     _temp_dir: TempDir,
     _settings_scope: SettingsBindDropGuard,

crates/red_knot_ide/src/db.rs

@@ -10,7 +10,7 @@ pub(crate) mod tests {
 
     use super::Db;
     use red_knot_python_semantic::lint::{LintRegistry, RuleSelection};
-    use red_knot_python_semantic::{default_lint_registry, Db as SemanticDb};
+    use red_knot_python_semantic::{default_lint_registry, Db as SemanticDb, Program};
     use ruff_db::files::{File, Files};
     use ruff_db::system::{DbWithTestSystem, System, TestSystem};
     use ruff_db::vendored::VendoredFileSystem;
@@ -83,6 +83,10 @@ pub(crate) mod tests {
         fn files(&self) -> &Files {
             &self.files
         }
+
+        fn python_version(&self) -> ruff_python_ast::PythonVersion {
+            Program::get(self).python_version(self)
+        }
     }
 
     impl Upcast<dyn SourceDb> for TestDb {

crates/red_knot_ide/src/goto.rs

@@ -421,16 +421,16 @@ mod tests {
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r#"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:4:13
@@ -440,7 +440,7 @@ mod tests {
         4 |             a
           |             ^
           |
-        "###);
+        "#);
     }
     #[test]
     fn goto_type_of_expression_with_literal_node() {
@@ -450,16 +450,16 @@ mod tests {
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r#"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:2:22
@@ -467,7 +467,7 @@ mod tests {
         2 |             a: str = "test"
           |                      ^^^^^^
           |
-        "###);
+        "#);
     }
 
     #[test]
@@ -532,16 +532,16 @@ mod tests {
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r#"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:4:18
@@ -551,7 +551,7 @@ mod tests {
         4 |             test(a= "123")
           |                  ^
           |
-        "###);
+        "#);
     }
 
     #[test]
@@ -567,16 +567,16 @@ mod tests {
         // TODO: This should jump to `str` and not `int` because
         //   the keyword is typed as a string. It's only the passed argument that
         //   is an int. Navigating to `str` would match pyright's behavior.
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:234:7
+           --> stdlib/builtins.pyi:231:7
             |
-        232 | _LiteralInteger = _PositiveInteger | _NegativeInteger | Literal[0]  # noqa: Y026  # TODO: Use TypeAlias once mypy bugs are fixed
-        233 |
-        234 | class int:
+        229 | _LiteralInteger = _PositiveInteger | _NegativeInteger | Literal[0]  # noqa: Y026  # TODO: Use TypeAlias once mypy bugs are fixed
+        230 |
+        231 | class int:
             |       ^^^
-        235 |     @overload
-        236 |     def __new__(cls, x: ConvertibleToInt = ..., /) -> Self: ...
+        232 |     @overload
+        233 |     def __new__(cls, x: ConvertibleToInt = ..., /) -> Self: ...
             |
         info: Source
          --> /main.py:4:18
@@ -586,7 +586,7 @@ mod tests {
         4 |             test(a= 123)
           |                  ^
           |
-        "###);
+        ");
     }
 
     #[test]
@@ -601,16 +601,16 @@ f(**kwargs<CURSOR>)
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r#"
         info: lint:goto-type-definition: Type definition
-            --> stdlib/builtins.pyi:1098:7
+            --> stdlib/builtins.pyi:1086:7
              |
-        1096 |         def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
-        1097 |
-        1098 | class dict(MutableMapping[_KT, _VT]):
+        1084 |     def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
+        1085 |
+        1086 | class dict(MutableMapping[_KT, _VT]):
              |       ^^^^
-        1099 |     # __init__ should be kept roughly in line with `collections.UserDict.__init__`, which has similar semantics
-        1100 |     # Also multiprocessing.managers.SyncManager.dict()
+        1087 |     # __init__ should be kept roughly in line with `collections.UserDict.__init__`, which has similar semantics
+        1088 |     # Also multiprocessing.managers.SyncManager.dict()
              |
         info: Source
          --> /main.py:6:5
@@ -620,7 +620,7 @@ f(**kwargs<CURSOR>)
         6 | f(**kwargs)
           |     ^^^^^^
           |
-        "###);
+        "#);
     }
 
     #[test]
@@ -632,16 +632,16 @@ f(**kwargs<CURSOR>)
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:3:17
@@ -650,7 +650,7 @@ f(**kwargs<CURSOR>)
         3 |                 a
           |                 ^
           |
-        "###);
+        ");
     }
 
     #[test]
@@ -725,16 +725,16 @@ f(**kwargs<CURSOR>)
             "#,
         );
 
-        assert_snapshot!(test.goto_type_definition(), @r###"
+        assert_snapshot!(test.goto_type_definition(), @r"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:4:27
@@ -744,7 +744,7 @@ f(**kwargs<CURSOR>)
         4 |                     print(a)
           |                           ^
           |
-        "###);
+        ");
     }
 
     #[test]
@@ -758,13 +758,13 @@ f(**kwargs<CURSOR>)
 
         assert_snapshot!(test.goto_type_definition(), @r"
         info: lint:goto-type-definition: Type definition
-           --> stdlib/types.pyi:677:11
+           --> stdlib/types.pyi:671:11
             |
-        675 | if sys.version_info >= (3, 10):
-        676 |     @final
-        677 |     class NoneType:
+        669 | if sys.version_info >= (3, 10):
+        670 |     @final
+        671 |     class NoneType:
             |           ^^^^^^^^
-        678 |         def __bool__(self) -> Literal[False]: ...
+        672 |         def __bool__(self) -> Literal[False]: ...
             |
         info: Source
          --> /main.py:3:17
@@ -775,14 +775,14 @@ f(**kwargs<CURSOR>)
           |
 
         info: lint:goto-type-definition: Type definition
-           --> stdlib/builtins.pyi:443:7
+           --> stdlib/builtins.pyi:438:7
             |
-        441 |     def __getitem__(self, key: int, /) -> str | int | None: ...
-        442 |
-        443 | class str(Sequence[str]):
+        436 |     def __getitem__(self, key: int, /) -> str | int | None: ...
+        437 |
+        438 | class str(Sequence[str]):
             |       ^^^
-        444 |     @overload
-        445 |     def __new__(cls, object: object = ...) -> Self: ...
+        439 |     @overload
+        440 |     def __new__(cls, object: object = ...) -> Self: ...
             |
         info: Source
          --> /main.py:3:17

crates/red_knot_ide/src/hover.rs

@@ -214,11 +214,11 @@ mod tests {
         "#,
         );
 
-        assert_snapshot!(test.hover(), @r"
-        Literal[foo]
+        assert_snapshot!(test.hover(), @r###"
+        def foo(a, b) -> Unknown
         ---------------------------------------------
         ```text
-        Literal[foo]
+        def foo(a, b) -> Unknown
         ```
         ---------------------------------------------
         info: lint:hover: Hovered content is
@@ -231,7 +231,7 @@ mod tests {
           |             |
           |             source
           |
-        ");
+        "###);
     }
 
     #[test]
@@ -312,11 +312,11 @@ mod tests {
             "#,
         );
 
-        assert_snapshot!(test.hover(), @r"
-        Literal[foo, bar]
+        assert_snapshot!(test.hover(), @r###"
+        (def foo(a, b) -> Unknown) | (def bar(a, b) -> Unknown)
         ---------------------------------------------
         ```text
-        Literal[foo, bar]
+        (def foo(a, b) -> Unknown) | (def bar(a, b) -> Unknown)
         ```
         ---------------------------------------------
         info: lint:hover: Hovered content is
@@ -329,7 +329,7 @@ mod tests {
            |             |
            |             source
            |
-        ");
+        "###);
     }
 
     #[test]

crates/red_knot_project/resources/test/corpus/cycle_narrowing_constraints.py

@@ -0,0 +1,15 @@
+# Regression test for https://github.com/astral-sh/ruff/issues/17215
+# panicked in commit 1a6a10b30
+# error message:
+# dependency graph cycle querying all_narrowing_constraints_for_expression(Id(8591))
+
+def f(a: A, b: B, c: C):
+    unknown_a: UA = make_unknown()
+    unknown_b: UB = make_unknown()
+    unknown_c: UC = make_unknown()
+    unknown_d: UD = make_unknown()
+
+    if unknown_a and unknown_b:
+        if unknown_c:
+            if unknown_d:
+                return a, b, c

crates/red_knot_project/resources/test/corpus/cycle_negative_narrowing_constraints.py

@@ -0,0 +1,22 @@
+# Regression test for https://github.com/astral-sh/ruff/issues/17215
+# panicked in commit 1a6a10b30
+# error message:
+# dependency graph cycle querying all_negative_narrowing_constraints_for_expression(Id(859f))
+
+def f(f1: bool, f2: bool, f3: bool, f4: bool):
+    o1: UnknownClass = make_o()
+    o2: UnknownClass = make_o()
+    o3: UnknownClass = make_o()
+    o4: UnknownClass = make_o()
+
+    if f1 and f2 and f3 and f4:
+        if o1 == o2:
+            return None
+        if o2 == o3:
+            return None
+        if o3 == o4:
+            return None
+        if o4 == o1:
+            return None
+
+    return o1, o2, o3, o4

crates/red_knot_project/src/db.rs

@@ -149,6 +149,10 @@ impl SourceDb for ProjectDatabase {
     fn files(&self) -> &Files {
         &self.files
     }
+
+    fn python_version(&self) -> ruff_python_ast::PythonVersion {
+        Program::get(self).python_version(self)
+    }
 }
 
 #[salsa::db]
@@ -207,7 +211,7 @@ pub(crate) mod tests {
     use salsa::Event;
 
     use red_knot_python_semantic::lint::{LintRegistry, RuleSelection};
-    use red_knot_python_semantic::Db as SemanticDb;
+    use red_knot_python_semantic::{Db as SemanticDb, Program};
     use ruff_db::files::Files;
     use ruff_db::system::{DbWithTestSystem, System, TestSystem};
     use ruff_db::vendored::VendoredFileSystem;
@@ -281,6 +285,10 @@ pub(crate) mod tests {
         fn files(&self) -> &Files {
             &self.files
         }
+
+        fn python_version(&self) -> ruff_python_ast::PythonVersion {
+            Program::get(self).python_version(self)
+        }
     }
 
     impl Upcast<dyn SemanticDb> for TestDb {

crates/red_knot_project/src/lib.rs

@@ -10,7 +10,8 @@ use red_knot_python_semantic::lint::{LintRegistry, LintRegistryBuilder, RuleSele
 use red_knot_python_semantic::register_lints;
 use red_knot_python_semantic::types::check_types;
 use ruff_db::diagnostic::{
-    create_parse_diagnostic, Annotation, Diagnostic, DiagnosticId, Severity, Span,
+    create_parse_diagnostic, create_unsupported_syntax_diagnostic, Annotation, Diagnostic,
+    DiagnosticId, Severity, Span,
 };
 use ruff_db::files::File;
 use ruff_db::parsed::parsed_module;
@@ -424,6 +425,13 @@ fn check_file_impl(db: &dyn Db, file: File) -> Vec<Diagnostic> {
             .map(|error| create_parse_diagnostic(file, error)),
     );
 
+    diagnostics.extend(
+        parsed
+            .unsupported_syntax_errors()
+            .iter()
+            .map(|error| create_unsupported_syntax_diagnostic(file, error)),
+    );
+
     diagnostics.extend(check_types(db.upcast(), file).into_iter().cloned());
 
     diagnostics.sort_unstable_by_key(|diagnostic| {
@@ -520,11 +528,13 @@ mod tests {
     use crate::db::tests::TestDb;
     use crate::{check_file_impl, ProjectMetadata};
     use red_knot_python_semantic::types::check_types;
+    use red_knot_python_semantic::{Program, ProgramSettings, PythonPlatform, SearchPathSettings};
     use ruff_db::files::system_path_to_file;
     use ruff_db::source::source_text;
     use ruff_db::system::{DbWithTestSystem, DbWithWritableSystem as _, SystemPath, SystemPathBuf};
     use ruff_db::testing::assert_function_query_was_not_run;
     use ruff_python_ast::name::Name;
+    use ruff_python_ast::PythonVersion;
 
     #[test]
     fn check_file_skips_type_checking_when_file_cant_be_read() -> ruff_db::system::Result<()> {
@@ -532,6 +542,16 @@ mod tests {
         let mut db = TestDb::new(project);
         let path = SystemPath::new("test.py");
 
+        Program::from_settings(
+            &db,
+            ProgramSettings {
+                python_version: PythonVersion::default(),
+                python_platform: PythonPlatform::default(),
+                search_paths: SearchPathSettings::new(vec![SystemPathBuf::from(".")]),
+            },
+        )
+        .expect("Failed to configure program settings");
+
         db.write_file(path, "x = 10")?;
         let file = system_path_to_file(&db, path).unwrap();
 

crates/red_knot_project/tests/check.rs

@@ -6,7 +6,9 @@ use ruff_db::parsed::parsed_module;
 use ruff_db::system::{SystemPath, SystemPathBuf, TestSystem};
 use ruff_python_ast::visitor::source_order;
 use ruff_python_ast::visitor::source_order::SourceOrderVisitor;
-use ruff_python_ast::{self as ast, Alias, Expr, Parameter, ParameterWithDefault, Stmt};
+use ruff_python_ast::{
+    self as ast, Alias, Comprehension, Expr, Parameter, ParameterWithDefault, Stmt,
+};
 
 fn setup_db(project_root: &SystemPath, system: TestSystem) -> anyhow::Result<ProjectDatabase> {
     let project = ProjectMetadata::discover(project_root, &system)?;
@@ -258,6 +260,14 @@ impl SourceOrderVisitor<'_> for PullTypesVisitor<'_> {
         source_order::walk_expr(self, expr);
     }
 
+    fn visit_comprehension(&mut self, comprehension: &Comprehension) {
+        self.visit_expr(&comprehension.iter);
+        self.visit_target(&comprehension.target);
+        for if_expr in &comprehension.ifs {
+            self.visit_expr(if_expr);
+        }
+    }
+
     fn visit_parameter(&mut self, parameter: &Parameter) {
         let _ty = parameter.inferred_type(&self.model);
 

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

@@ -237,6 +237,11 @@ def _(c: Callable[[Concatenate[int, str, ...], int], int]):
 
 ## Using `typing.ParamSpec`
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 Using a `ParamSpec` in a `Callable` annotation:
 
 ```py
@@ -289,7 +294,7 @@ def _(c: Callable[[int, Unpack[Ts]], int]):
 from typing import Callable
 
 def _(c: Callable[[int], int]):
-    reveal_type(c.__init__)  # revealed: Literal[__init__]
+    reveal_type(c.__init__)  # revealed: def __init__(self) -> None
     reveal_type(c.__class__)  # revealed: type
 
     # TODO: The member lookup for `Callable` uses `object` which does not have a `__call__`

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

@@ -48,6 +48,11 @@ reveal_type(get_foo())  # revealed: Foo
 
 ## Deferred self-reference annotations in a class definition
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 from __future__ import annotations
 
@@ -94,6 +99,11 @@ class Foo:
 
 ## Non-deferred self-reference annotations in a class definition
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 class Foo:
     # error: [unresolved-reference]
@@ -146,3 +156,24 @@ def _():
         def f(self) -> C:
             return self
 ```
+
+## Base class references
+
+### Not deferred by __future__.annotations
+
+```py
+from __future__ import annotations
+
+class A(B):  # error: [unresolved-reference]
+    pass
+
+class B:
+    pass
+```
+
+### Deferred in stub files
+
+```pyi
+class A(B): ...
+class B: ...
+```

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

@@ -89,7 +89,7 @@ def _(
     reveal_type(k)  # revealed: Unknown
     reveal_type(p)  # revealed: Unknown
     reveal_type(q)  # revealed: int | Unknown
-    reveal_type(r)  # revealed: @Todo(generics)
+    reveal_type(r)  # revealed: @Todo(unknown type subscript)
 ```
 
 ## Invalid Collection based AST nodes

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

@@ -68,7 +68,7 @@ def x(
     a3: Literal[Literal["w"], Literal["r"], Literal[Literal["w+"]]],
     a4: Literal[True] | Literal[1, 2] | Literal["foo"],
 ):
-    reveal_type(a1)  # revealed: Literal[1, 2, 3, "foo", 5] | None
+    reveal_type(a1)  # revealed: Literal[1, 2, 3, 5, "foo"] | None
     reveal_type(a2)  # revealed: Literal["w", "r"]
     reveal_type(a3)  # revealed: Literal["w", "r", "w+"]
     reveal_type(a4)  # revealed: Literal[True, 1, 2, "foo"]
@@ -108,7 +108,7 @@ def union_example(
         None,
     ],
 ):
-    reveal_type(x)  # revealed: Unknown | Literal[-1, "A", b"A", b"\x00", b"\x07", 0, 1, "B", "foo", "bar", True] | None
+    reveal_type(x)  # revealed: Unknown | Literal[-1, 0, 1, "A", "B", "foo", "bar", b"A", b"\x00", b"\x07", True] | None
 ```
 
 ## Detecting Literal outside typing and typing_extensions
@@ -137,7 +137,7 @@ from other import Literal
 a1: Literal[26]
 
 def f():
-    reveal_type(a1)  # revealed: @Todo(generics)
+    reveal_type(a1)  # revealed: @Todo(unknown type subscript)
 ```
 
 ## Detecting typing_extensions.Literal

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

@@ -72,13 +72,11 @@ reveal_type(baz)  # revealed: Literal["bazfoo"]
 qux = (foo, bar)
 reveal_type(qux)  # revealed: tuple[Literal["foo"], Literal["bar"]]
 
-# TODO: Infer "LiteralString"
-reveal_type(foo.join(qux))  # revealed: @Todo(return type of overloaded function)
+reveal_type(foo.join(qux))  # revealed: LiteralString
 
 template: LiteralString = "{}, {}"
 reveal_type(template)  # revealed: Literal["{}, {}"]
-# TODO: Infer `LiteralString`
-reveal_type(template.format(foo, bar))  # revealed: @Todo(return type of overloaded function)
+reveal_type(template.format(foo, bar))  # revealed: LiteralString
 ```
 
 ### Assignability

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

@@ -12,7 +12,7 @@ X = GenericAlias(type, ())
 A = NewType("A", int)
 # TODO: typeshed for `typing.GenericAlias` uses `type` for the first argument. `NewType` should be special-cased
 # to be compatible with `type`
-# error: [invalid-argument-type] "Object of type `NewType` cannot be assigned to parameter 2 (`origin`) of function `__new__`; expected type `type`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `type`, found `NewType`"
 B = GenericAlias(A, ())
 
 def _(

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

@@ -1,5 +1,10 @@
 # Starred expression annotations
 
+```toml
+[environment]
+python-version = "3.11"
+```
+
 Type annotations for `*args` can be starred expressions themselves:
 
 ```py

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

@@ -67,21 +67,24 @@ import typing
 
 ####################
 ### Built-ins
+####################
 
 class ListSubclass(typing.List): ...
 
-# revealed: tuple[Literal[ListSubclass], Literal[list], Literal[MutableSequence], Literal[Sequence], Literal[Reversible], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(protocol), Literal[object]]
+# TODO: generic protocols
+# revealed: tuple[Literal[ListSubclass], Literal[list], Literal[MutableSequence], Literal[Sequence], Literal[Reversible], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(`Protocol[]` subscript), @Todo(`Generic[]` subscript), Literal[object]]
 reveal_type(ListSubclass.__mro__)
 
 class DictSubclass(typing.Dict): ...
 
-# TODO: should have `Generic`, should not have `Unknown`
-# revealed: tuple[Literal[DictSubclass], Literal[dict], Unknown, Literal[object]]
+# TODO: generic protocols
+# revealed: tuple[Literal[DictSubclass], Literal[dict], Literal[MutableMapping], Literal[Mapping], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(`Protocol[]` subscript), @Todo(`Generic[]` subscript), Literal[object]]
 reveal_type(DictSubclass.__mro__)
 
 class SetSubclass(typing.Set): ...
 
-# revealed: tuple[Literal[SetSubclass], Literal[set], Literal[MutableSet], Literal[AbstractSet], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(protocol), Literal[object]]
+# TODO: generic protocols
+# revealed: tuple[Literal[SetSubclass], Literal[set], Literal[MutableSet], Literal[AbstractSet], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(`Protocol[]` subscript), @Todo(`Generic[]` subscript), Literal[object]]
 reveal_type(SetSubclass.__mro__)
 
 class FrozenSetSubclass(typing.FrozenSet): ...
@@ -92,11 +95,12 @@ reveal_type(FrozenSetSubclass.__mro__)
 
 ####################
 ### `collections`
+####################
 
 class ChainMapSubclass(typing.ChainMap): ...
 
-# TODO: Should be (ChainMapSubclass, ChainMap, MutableMapping, Mapping, Collection, Sized, Iterable, Container, Generic, object)
-# revealed: tuple[Literal[ChainMapSubclass], Literal[ChainMap], Unknown, Literal[object]]
+# TODO: generic protocols
+# revealed: tuple[Literal[ChainMapSubclass], Literal[ChainMap], Literal[MutableMapping], Literal[Mapping], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(`Protocol[]` subscript), @Todo(`Generic[]` subscript), Literal[object]]
 reveal_type(ChainMapSubclass.__mro__)
 
 class CounterSubclass(typing.Counter): ...
@@ -113,7 +117,8 @@ reveal_type(DefaultDictSubclass.__mro__)
 
 class DequeSubclass(typing.Deque): ...
 
-# revealed: tuple[Literal[DequeSubclass], Literal[deque], Literal[MutableSequence], Literal[Sequence], Literal[Reversible], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(protocol), Literal[object]]
+# TODO: generic protocols
+# revealed: tuple[Literal[DequeSubclass], Literal[deque], Literal[MutableSequence], Literal[Sequence], Literal[Reversible], Literal[Collection], Literal[Iterable], Literal[Container], @Todo(`Protocol[]` subscript), @Todo(`Generic[]` subscript), Literal[object]]
 reveal_type(DequeSubclass.__mro__)
 
 class OrderedDictSubclass(typing.OrderedDict): ...

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

@@ -105,7 +105,7 @@ def f1(
 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", b"c", "de", "f", "g", "h"]
+    reveal_type(v)  # revealed: Literal["a", "b", "de", "f", "g", "h", b"c"]
 ```
 
 ## Class variables

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

@@ -41,7 +41,7 @@ class Foo:
 One thing that is supported is error messages for using special forms in type expressions.
 
 ```py
-from typing_extensions import Unpack, TypeGuard, TypeIs, Concatenate, ParamSpec
+from typing_extensions import Unpack, TypeGuard, TypeIs, Concatenate, ParamSpec, Generic
 
 def _(
     a: Unpack,  # error: [invalid-type-form] "`typing.Unpack` requires exactly one argument when used in a type expression"
@@ -49,6 +49,7 @@ def _(
     c: TypeIs,  # error: [invalid-type-form] "`typing.TypeIs` requires exactly one argument when used in a type expression"
     d: Concatenate,  # error: [invalid-type-form] "`typing.Concatenate` requires at least two arguments when used in a type expression"
     e: ParamSpec,
+    f: Generic,  # error: [invalid-type-form] "`typing.Generic` is not allowed in type expressions"
 ) -> None:
     reveal_type(a)  # revealed: Unknown
     reveal_type(b)  # revealed: Unknown
@@ -65,7 +66,7 @@ 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
+from typing_extensions import Self, Unpack, TypeGuard, TypeIs, Concatenate, Generic
 
 class A(Self): ...  # error: [invalid-base]
 class B(Unpack): ...  # error: [invalid-base]
@@ -73,12 +74,18 @@ class C(TypeGuard): ...  # error: [invalid-base]
 class D(TypeIs): ...  # error: [invalid-base]
 class E(Concatenate): ...  # error: [invalid-base]
 class F(Callable): ...
+class G(Generic): ...  # error: [invalid-base] "Cannot inherit from plain `Generic`"
 
 reveal_type(F.__mro__)  # revealed: tuple[Literal[F], @Todo(Support for Callable as a base class), Literal[object]]
 ```
 
 ## Subscriptability
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 Some of these are not subscriptable:
 
 ```py

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

@@ -25,6 +25,11 @@ x = "foo"  # error: [invalid-assignment] "Object of type `Literal["foo"]` is not
 
 ## Tuple annotations are understood
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 `module.py`:
 
 ```py
@@ -56,7 +61,7 @@ reveal_type(d)  # revealed: tuple[tuple[str, str], tuple[int, int]]
 reveal_type(e)  # revealed: @Todo(full tuple[...] support)
 reveal_type(f)  # revealed: @Todo(full tuple[...] support)
 reveal_type(g)  # revealed: @Todo(full tuple[...] support)
-reveal_type(h)  # revealed: tuple[@Todo(generics), @Todo(generics)]
+reveal_type(h)  # revealed: tuple[@Todo(specialized non-generic class), @Todo(specialized non-generic class)]
 
 reveal_type(i)  # revealed: tuple[str | int, str | int]
 reveal_type(j)  # revealed: tuple[str | int]

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -41,8 +41,7 @@ reveal_type(c_instance.declared_only)  # revealed: bytes
 
 reveal_type(c_instance.declared_and_bound)  # revealed: bool
 
-# We probably don't want to emit a diagnostic for this being possibly undeclared/unbound.
-# mypy and pyright do not show an error here.
+# error: [possibly-unbound-attribute]
 reveal_type(c_instance.possibly_undeclared_unbound)  # revealed: str
 
 # This assignment is fine, as we infer `Unknown | Literal[1, "a"]` for `inferred_from_value`.
@@ -303,7 +302,7 @@ class C:
 
 c_instance = C()
 reveal_type(c_instance.a)  # revealed: Unknown | Literal[1]
-reveal_type(c_instance.b)  # revealed: Unknown | @Todo(starred unpacking)
+reveal_type(c_instance.b)  # revealed: Unknown
 ```
 
 #### Attributes defined in for-loop (unpacking)
@@ -339,8 +338,10 @@ class C:
         for self.z in NonIterable():
             pass
 
+# Iterable might be empty
+# error: [possibly-unbound-attribute]
 reveal_type(C().x)  # revealed: Unknown | int
-
+# error: [possibly-unbound-attribute]
 reveal_type(C().y)  # revealed: Unknown | str
 ```
 
@@ -396,21 +397,33 @@ class IntIterable:
     def __iter__(self) -> IntIterator:
         return IntIterator()
 
+class TupleIterator:
+    def __next__(self) -> tuple[int, str]:
+        return (1, "a")
+
+class TupleIterable:
+    def __iter__(self) -> TupleIterator:
+        return TupleIterator()
+
 class C:
     def __init__(self) -> None:
         [... for self.a in IntIterable()]
+        [... for (self.b, self.c) in TupleIterable()]
+        [... for self.d in IntIterable() for self.e in IntIterable()]
 
 c_instance = C()
 
-# TODO: Should be `Unknown | int`
-# error: [unresolved-attribute]
-reveal_type(c_instance.a)  # revealed: Unknown
+reveal_type(c_instance.a)  # revealed: Unknown | int
+reveal_type(c_instance.b)  # revealed: Unknown | int
+reveal_type(c_instance.c)  # revealed: Unknown | str
+reveal_type(c_instance.d)  # revealed: Unknown | int
+reveal_type(c_instance.e)  # revealed: Unknown | int
 ```
 
 #### Conditionally declared / bound attributes
 
-We currently do not raise a diagnostic or change behavior if an attribute is only conditionally
-defined. This is consistent with what mypy and pyright do.
+Attributes are possibly unbound if they, or the method to which they are added are conditionally
+declared / bound.
 
 ```py
 def flag() -> bool:
@@ -428,9 +441,13 @@ class C:
 
 c_instance = C()
 
+# error: [possibly-unbound-attribute]
 reveal_type(c_instance.a1)  # revealed: str | None
+# error: [possibly-unbound-attribute]
 reveal_type(c_instance.a2)  # revealed: str | None
+# error: [possibly-unbound-attribute]
 reveal_type(c_instance.b1)  # revealed: Unknown | Literal[1]
+# error: [possibly-unbound-attribute]
 reveal_type(c_instance.b2)  # revealed: Unknown | Literal[1]
 ```
 
@@ -539,10 +556,88 @@ class C:
         if (2 + 3) < 4:
             self.x: str = "a"
 
-# TODO: Ideally, this would result in a `unresolved-attribute` error. But mypy and pyright
-# do not support this either (for conditions that can only be resolved to `False` in type
-# inference), so it does not seem to be particularly important.
-reveal_type(C().x)  # revealed: str
+# error: [unresolved-attribute]
+reveal_type(C().x)  # revealed: Unknown
+```
+
+```py
+class C:
+    def __init__(self, cond: bool) -> None:
+        if True:
+            self.a = 1
+        else:
+            self.a = "a"
+
+        if False:
+            self.b = 2
+
+        if cond:
+            return
+
+        self.c = 3
+
+        self.d = 4
+        self.d = 5
+
+    def set_c(self, c: str) -> None:
+        self.c = c
+    if False:
+        def set_e(self, e: str) -> None:
+            self.e = e
+
+reveal_type(C(True).a)  # revealed: Unknown | Literal[1]
+# error: [unresolved-attribute]
+reveal_type(C(True).b)  # revealed: Unknown
+reveal_type(C(True).c)  # revealed: Unknown | Literal[3] | str
+# TODO: this attribute is possibly unbound
+reveal_type(C(True).d)  # revealed: Unknown | Literal[5]
+# error: [unresolved-attribute]
+reveal_type(C(True).e)  # revealed: Unknown
+```
+
+#### Attributes considered always bound
+
+```py
+class C:
+    def __init__(self, cond: bool):
+        self.x = 1
+        if cond:
+            raise ValueError("Something went wrong")
+
+        # We consider this attribute is always bound.
+        # This is because, it is not possible to access a partially-initialized object by normal means.
+        self.y = 2
+
+reveal_type(C(False).x)  # revealed: Unknown | Literal[1]
+reveal_type(C(False).y)  # revealed: Unknown | Literal[2]
+
+class C:
+    def __init__(self, b: bytes) -> None:
+        self.b = b
+
+        try:
+            s = b.decode()
+        except UnicodeDecodeError:
+            raise ValueError("Invalid UTF-8 sequence")
+
+        self.s = s
+
+reveal_type(C(b"abc").b)  # revealed: Unknown | bytes
+reveal_type(C(b"abc").s)  # revealed: Unknown | str
+
+class C:
+    def __init__(self, iter) -> None:
+        self.x = 1
+
+        for _ in iter:
+            pass
+
+        # The for-loop may not stop,
+        # but we consider the subsequent attributes to be definitely-bound.
+        self.y = 2
+
+reveal_type(C([]).x)  # revealed: Unknown | Literal[1]
+reveal_type(C([]).y)  # revealed: Unknown | Literal[2]
 ```
 
 #### Diagnostics are reported for the right-hand side of attribute assignments
@@ -1046,13 +1141,18 @@ def _(flag: bool):
         def __init(self):
             if flag:
                 self.x = 1
+                self.y = "a"
+            else:
+                self.y = "b"
 
-    # Emitting a diagnostic in a case like this is not something we support, and it's unclear
-    # if we ever will (or want to)
+    # error: [possibly-unbound-attribute]
     reveal_type(Foo().x)  # revealed: Unknown | Literal[1]
 
-    # Same here
+    # error: [possibly-unbound-attribute]
     Foo().x = 2
+
+    reveal_type(Foo().y)  # revealed: Unknown | Literal["a", "b"]
+    Foo().y = "c"
 ```
 
 ### Unions with all paths unbound
@@ -1285,7 +1385,7 @@ from typing import Any
 class Foo(Any): ...
 
 reveal_type(Foo.bar)  # revealed: Any
-reveal_type(Foo.__repr__)  # revealed: Literal[__repr__] & Any
+reveal_type(Foo.__repr__)  # revealed: (def __repr__(self) -> str) & Any
 ```
 
 Similar principles apply if `Any` appears in the middle of an inheritance hierarchy:
@@ -1577,14 +1677,14 @@ functions are instances of that class:
 def f(): ...
 
 reveal_type(f.__defaults__)  # revealed: @Todo(full tuple[...] support) | None
-reveal_type(f.__kwdefaults__)  # revealed: @Todo(generics) | None
+reveal_type(f.__kwdefaults__)  # revealed: @Todo(specialized non-generic class) | None
 ```
 
 Some attributes are special-cased, however:
 
 ```py
 reveal_type(f.__get__)  # revealed: <method-wrapper `__get__` of `f`>
-reveal_type(f.__call__)  # revealed: <bound method `__call__` of `Literal[f]`>
+reveal_type(f.__call__)  # revealed: <method-wrapper `__call__` of `f`>
 ```
 
 ### Int-literal attributes
@@ -1593,7 +1693,7 @@ Most attribute accesses on int-literal types are delegated to `builtins.int`, si
 integers are instances of that class:
 
 ```py
-reveal_type((2).bit_length)  # revealed: <bound method `bit_length` of `Literal[2]`>
+reveal_type((2).bit_length)  # revealed: bound method Literal[2].bit_length() -> int
 reveal_type((2).denominator)  # revealed: Literal[1]
 ```
 
@@ -1610,8 +1710,10 @@ Most attribute accesses on bool-literal types are delegated to `builtins.bool`,
 bools are instances of that class:
 
 ```py
-reveal_type(True.__and__)  # revealed: <bound method `__and__` of `Literal[True]`>
-reveal_type(False.__or__)  # revealed: <bound method `__or__` of `Literal[False]`>
+# revealed: Overload[(value: bool, /) -> bool, (value: int, /) -> int]
+reveal_type(True.__and__)
+# revealed: Overload[(value: bool, /) -> bool, (value: int, /) -> int]
+reveal_type(False.__or__)
 ```
 
 Some attributes are special-cased, however:
@@ -1626,8 +1728,10 @@ reveal_type(False.real)  # revealed: Literal[0]
 All attribute access on literal `bytes` types is currently delegated to `builtins.bytes`:
 
 ```py
-reveal_type(b"foo".join)  # revealed: <bound method `join` of `Literal[b"foo"]`>
-reveal_type(b"foo".endswith)  # revealed: <bound method `endswith` of `Literal[b"foo"]`>
+# revealed: bound method Literal[b"foo"].join(iterable_of_bytes: @Todo(specialized non-generic class), /) -> bytes
+reveal_type(b"foo".join)
+# revealed: bound method Literal[b"foo"].endswith(suffix: @Todo(Support for `typing.TypeAlias`), start: SupportsIndex | None = ellipsis, end: SupportsIndex | None = ellipsis, /) -> bool
+reveal_type(b"foo".endswith)
 ```
 
 ## Instance attribute edge cases
@@ -1728,6 +1832,89 @@ def f(never: Never):
     never.another_attribute = never
 ```
 
+### Cyclic implicit attributes
+
+Inferring types for undeclared implicit attributes can be cyclic:
+
+```py
+class C:
+    def __init__(self):
+        self.x = 1
+
+    def copy(self, other: "C"):
+        self.x = other.x
+
+reveal_type(C().x)  # revealed: Unknown | Literal[1]
+```
+
+If the only assignment to a name is cyclic, we just infer `Unknown` for that attribute:
+
+```py
+class D:
+    def copy(self, other: "D"):
+        self.x = other.x
+
+reveal_type(D().x)  # revealed: Unknown
+```
+
+If there is an annotation for a name, we don't try to infer any type from the RHS of assignments to
+that name, so these cases don't trigger any cycle:
+
+```py
+class E:
+    def __init__(self):
+        self.x: int = 1
+
+    def copy(self, other: "E"):
+        self.x = other.x
+
+reveal_type(E().x)  # revealed: int
+
+class F:
+    def __init__(self):
+        self.x = 1
+
+    def copy(self, other: "F"):
+        self.x: int = other.x
+
+reveal_type(F().x)  # revealed: int
+
+class G:
+    def copy(self, other: "G"):
+        self.x: int = other.x
+
+reveal_type(G().x)  # revealed: int
+```
+
+We can even handle cycles involving multiple classes:
+
+```py
+class A:
+    def __init__(self):
+        self.x = 1
+
+    def copy(self, other: "B"):
+        self.x = other.x
+
+class B:
+    def copy(self, other: "A"):
+        self.x = other.x
+
+reveal_type(B().x)  # revealed: Unknown | Literal[1]
+reveal_type(A().x)  # revealed: Unknown | Literal[1]
+```
+
+This case additionally tests our union/intersection simplification logic:
+
+```py
+class H:
+    def __init__(self):
+        self.x = 1
+
+    def copy(self, other: "H"):
+        self.x = other.x or self.x
+```
+
 ### Builtin types attributes
 
 This test can probably be removed eventually, but we currently include it because we do not yet
@@ -1779,20 +1966,6 @@ reveal_type(Foo.BAR.value)  # revealed: @Todo(Attribute access on enum classes)
 reveal_type(Foo.__members__)  # revealed: @Todo(Attribute access on enum classes)
 ```
 
-## `super()`
-
-`super()` is not supported yet, but we do not emit false positives on `super()` calls.
-
-```py
-class Foo:
-    def bar(self) -> int:
-        return 42
-
-class Bar(Foo):
-    def bar(self) -> int:
-        return super().bar()
-```
-
 ## References
 
 Some of the tests in the *Class and instance variables* section draw inspiration from

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

@@ -350,30 +350,30 @@ reveal_type(no() + no())  # revealed: Unknown
 def f():
     pass
 
-# error: [unsupported-operator] "Operator `+` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `+` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f + f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `-` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `-` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f - f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `*` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `*` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f * f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `@` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `@` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f @ f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `/` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `/` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f / f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `%` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `%` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f % f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `**` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `**` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f**f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `<<` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `<<` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f << f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `>>` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `>>` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f >> f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `|` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `|` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f | f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `^` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `^` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f ^ f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `&` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `&` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f & f)  # revealed: Unknown
-# error: [unsupported-operator] "Operator `//` is unsupported between objects of type `Literal[f]` and `Literal[f]`"
+# error: [unsupported-operator] "Operator `//` is unsupported between objects of type `def f() -> Unknown` and `def f() -> Unknown`"
 reveal_type(f // f)  # revealed: Unknown
 ```

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

@@ -310,9 +310,7 @@ reveal_type(A() + 1)  # revealed: A
 reveal_type(1 + A())  # revealed: A
 
 reveal_type(A() + "foo")  # revealed: A
-# TODO should be `A` since `str.__add__` doesn't support `A` instances
-# TODO overloads
-reveal_type("foo" + A())  # revealed: @Todo(return type of overloaded function)
+reveal_type("foo" + A())  # revealed: A
 
 reveal_type(A() + b"foo")  # revealed: A
 # TODO should be `A` since `bytes.__add__` doesn't support `A` instances
@@ -320,16 +318,14 @@ reveal_type(b"foo" + A())  # revealed: bytes
 
 reveal_type(A() + ())  # revealed: A
 # TODO this should be `A`, since `tuple.__add__` doesn't support `A` instances
-reveal_type(() + A())  # revealed: @Todo(return type of overloaded function)
+reveal_type(() + A())  # revealed: @Todo(full tuple[...] support)
 
 literal_string_instance = "foo" * 1_000_000_000
 # the test is not testing what it's meant to be testing if this isn't a `LiteralString`:
 reveal_type(literal_string_instance)  # revealed: LiteralString
 
 reveal_type(A() + literal_string_instance)  # revealed: A
-# TODO should be `A` since `str.__add__` doesn't support `A` instances
-# TODO overloads
-reveal_type(literal_string_instance + A())  # revealed: @Todo(return type of overloaded function)
+reveal_type(literal_string_instance + A())  # revealed: A
 ```
 
 ## Operations involving instances of classes inheriting from `Any`

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

@@ -50,9 +50,11 @@ reveal_type(1 ** (largest_u32 + 1))  # revealed: int
 reveal_type(2**largest_u32)  # revealed: int
 
 def variable(x: int):
-    reveal_type(x**2)  # revealed: @Todo(return type of overloaded function)
-    reveal_type(2**x)  # revealed: @Todo(return type of overloaded function)
-    reveal_type(x**x)  # revealed: @Todo(return type of overloaded function)
+    reveal_type(x**2)  # revealed: int
+    # TODO: should be `Any` (overload 5 on `__pow__`), requires correct overload matching
+    reveal_type(2**x)  # revealed: int
+    # TODO: should be `Any` (overload 5 on `__pow__`), requires correct overload matching
+    reveal_type(x**x)  # revealed: int
 ```
 
 If the second argument is \<0, a `float` is returned at runtime. If the first argument is \<0 but

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

@@ -43,7 +43,7 @@ if True and (x := 1):
 
 ```py
 def _(flag: bool):
-    flag or (x := 1) or reveal_type(x)  # revealed: Literal[1]
+    flag or (x := 1) or reveal_type(x)  # revealed: Never
 
     # error: [unresolved-reference]
     flag or reveal_type(y) or (y := 1)  # revealed: Unknown

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

@@ -9,8 +9,8 @@ def _(c: Callable[[], int]):
 def _(c: Callable[[int, str], int]):
     reveal_type(c(1, "a"))  # revealed: int
 
-    # error: [invalid-argument-type] "Object of type `Literal["a"]` cannot be assigned to parameter 1; expected type `int`"
-    # error: [invalid-argument-type] "Object of type `Literal[1]` cannot be assigned to parameter 2; expected type `str`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["a"]`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `str`, found `Literal[1]`"
     reveal_type(c("a", 1))  # revealed: int
 ```
 

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

@@ -85,7 +85,7 @@ class C:
 
 c = C()
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter 2 (`x`) of bound method `__call__`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(c("foo"))  # revealed: int
 ```
 
@@ -99,7 +99,7 @@ class C:
 
 c = C()
 
-# error: 13 [invalid-argument-type] "Object of type `C` cannot be assigned to parameter 1 (`self`) of bound method `__call__`; expected type `int`"
+# error: 13 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `C`"
 reveal_type(c())  # revealed: int
 ```
 

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

@@ -98,7 +98,7 @@ def _(flag: bool) -> None:
             def __new__(cls, x: int, y: int = 1): ...
 
     reveal_type(Foo(1))  # revealed: Foo
-    # error: [invalid-argument-type] "Object of type `Literal["1"]` cannot be assigned to parameter 2 (`x`) of function `__new__`; expected type `int`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["1"]`"
     reveal_type(Foo("1"))  # revealed: Foo
     # error: [missing-argument] "No argument provided for required parameter `x` of function `__new__`"
     reveal_type(Foo())  # revealed: Foo
@@ -210,7 +210,7 @@ def _(flag: bool) -> None:
             def __init__(self, x: int, y: int = 1): ...
 
     reveal_type(Foo(1))  # revealed: Foo
-    # error: [invalid-argument-type] "Object of type `Literal["1"]` cannot be assigned to parameter 2 (`x`) of bound method `__init__`; expected type `int`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["1"]`"
     reveal_type(Foo("1"))  # revealed: Foo
     # error: [missing-argument] "No argument provided for required parameter `x` of bound method `__init__`"
     reveal_type(Foo())  # revealed: Foo

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

@@ -21,6 +21,11 @@ reveal_type(get_int_async())  # revealed: @Todo(generic types.CoroutineType)
 
 ## Generic
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 def get_int[T]() -> int:
     return 42
@@ -72,7 +77,7 @@ def _(flag: bool):
 def f(x: int) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter 1 (`x`) of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f("foo"))  # revealed: int
 ```
 
@@ -82,7 +87,7 @@ reveal_type(f("foo"))  # revealed: int
 def f(x: int, /) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter 1 (`x`) of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f("foo"))  # revealed: int
 ```
 
@@ -92,7 +97,7 @@ reveal_type(f("foo"))  # revealed: int
 def f(*args: int) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter `*args` of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f("foo"))  # revealed: int
 ```
 
@@ -102,7 +107,7 @@ reveal_type(f("foo"))  # revealed: int
 def f(x: int) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter `x` of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f(x="foo"))  # revealed: int
 ```
 
@@ -112,7 +117,7 @@ reveal_type(f(x="foo"))  # revealed: int
 def f(*, x: int) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter `x` of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f(x="foo"))  # revealed: int
 ```
 
@@ -122,7 +127,7 @@ reveal_type(f(x="foo"))  # revealed: int
 def f(**kwargs: int) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter `**kwargs` of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 reveal_type(f(x="foo"))  # revealed: int
 ```
 
@@ -132,8 +137,8 @@ reveal_type(f(x="foo"))  # revealed: int
 def f(x: int = 1, y: str = "foo") -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal[2]` cannot be assigned to parameter `y` of function `f`; expected type `str`"
-# error: 20 [invalid-argument-type] "Object of type `Literal["bar"]` cannot be assigned to parameter `x` of function `f`; expected type `int`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `str`, found `Literal[2]`"
+# error: 20 [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["bar"]`"
 reveal_type(f(y=2, x="bar"))  # revealed: int
 ```
 

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

@@ -57,7 +57,8 @@ We can access attributes on objects of all kinds:
 import sys
 
 reveal_type(inspect.getattr_static(sys, "dont_write_bytecode"))  # revealed: bool
-reveal_type(inspect.getattr_static(inspect, "getattr_static"))  # revealed: Literal[getattr_static]
+# revealed: def getattr_static(obj: object, attr: str, default: Any | None = ellipsis) -> Any
+reveal_type(inspect.getattr_static(inspect, "getattr_static"))
 
 reveal_type(inspect.getattr_static(1, "real"))  # revealed: property
 ```
@@ -114,7 +115,7 @@ inspect.getattr_static()
 # error: [missing-argument] "No argument provided for required parameter `attr`"
 inspect.getattr_static(C())
 
-# error: [invalid-argument-type] "Object of type `Literal[1]` cannot be assigned to parameter 2 (`attr`) of function `getattr_static`; expected type `str`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `str`, found `Literal[1]`"
 inspect.getattr_static(C(), 1)
 
 # error: [too-many-positional-arguments] "Too many positional arguments to function `getattr_static`: expected 3, got 4"
@@ -143,8 +144,9 @@ from typing import Any
 def _(a: Any, tuple_of_any: tuple[Any]):
     reveal_type(inspect.getattr_static(a, "x", "default"))  # revealed: Any | Literal["default"]
 
-    # TODO: Ideally, this would just be `Literal[index]`
-    reveal_type(inspect.getattr_static(tuple_of_any, "index", "default"))  # revealed: Literal[index] | Literal["default"]
+    # TODO: Ideally, this would just be `def index(self, value: Any, start: SupportsIndex = Literal[0], stop: SupportsIndex = int, /) -> int`
+    # revealed: (def index(self, value: Any, start: SupportsIndex = Literal[0], stop: SupportsIndex = int, /) -> int) | Literal["default"]
+    reveal_type(inspect.getattr_static(tuple_of_any, "index", "default"))
 ```
 
 [official documentation]: https://docs.python.org/3/library/inspect.html#inspect.getattr_static

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

@@ -24,7 +24,7 @@ to the valid order:
 def f(**kw: int, x: str) -> int:
     return 1
 
-# error: 15 [invalid-argument-type] "Object of type `Literal[1]` cannot be assigned to parameter 1 (`x`) of function `f`; expected type `str`"
+# error: 15 [invalid-argument-type] "Argument to this function is incorrect: Expected `str`, found `Literal[1]`"
 reveal_type(f(1))  # revealed: int
 ```
 
@@ -38,7 +38,7 @@ def f(x: int = 1, y: str) -> int:
     return 1
 
 reveal_type(f(y="foo"))  # revealed: int
-# error: [invalid-argument-type] "Object of type `Literal["foo"]` cannot be assigned to parameter 1 (`x`) of function `f`; expected type `int`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["foo"]`"
 # error: [missing-argument] "No argument provided for required parameter `y` of function `f`"
 reveal_type(f("foo"))  # revealed: int
 ```

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

@@ -32,20 +32,20 @@ the latter case, it returns a *bound method* object:
 ```py
 from inspect import getattr_static
 
-reveal_type(getattr_static(C, "f"))  # revealed: Literal[f]
+reveal_type(getattr_static(C, "f"))  # revealed: def f(self, x: int) -> str
 
 reveal_type(getattr_static(C, "f").__get__)  # revealed: <method-wrapper `__get__` of `f`>
 
-reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: Literal[f]
-reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: <bound method `f` of `C`>
+reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: def f(self, x: int) -> str
+reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: bound method C.f(x: int) -> str
 ```
 
 In conclusion, this is why we see the following two types when accessing the `f` attribute on the
 class object `C` and on an instance `C()`:
 
 ```py
-reveal_type(C.f)  # revealed: Literal[f]
-reveal_type(C().f)  # revealed: <bound method `f` of `C`>
+reveal_type(C.f)  # revealed: def f(self, x: int) -> str
+reveal_type(C().f)  # revealed: bound method C.f(x: int) -> str
 ```
 
 A bound method is a callable object that contains a reference to the `instance` that it was called
@@ -56,7 +56,7 @@ via `__func__`):
 bound_method = C().f
 
 reveal_type(bound_method.__self__)  # revealed: C
-reveal_type(bound_method.__func__)  # revealed: Literal[f]
+reveal_type(bound_method.__func__)  # revealed: def f(self, x: int) -> str
 ```
 
 When we call the bound method, the `instance` is implicitly passed as the first argument (`self`):
@@ -80,13 +80,13 @@ When we access methods from derived classes, they will be bound to instances of
 class D(C):
     pass
 
-reveal_type(D().f)  # revealed: <bound method `f` of `D`>
+reveal_type(D().f)  # revealed: bound method D.f(x: int) -> str
 ```
 
 If we access an attribute on a bound method object itself, it will defer to `types.MethodType`:
 
 ```py
-reveal_type(bound_method.__hash__)  # revealed: <bound method `__hash__` of `MethodType`>
+reveal_type(bound_method.__hash__)  # revealed: bound method MethodType.__hash__() -> int
 ```
 
 If an attribute is not available on the bound method object, it will be looked up on the underlying
@@ -94,7 +94,7 @@ function object. We model this explicitly, which means that we can access `__kwd
 methods, even though it is not available on `types.MethodType`:
 
 ```py
-reveal_type(bound_method.__kwdefaults__)  # revealed: @Todo(generics) | None
+reveal_type(bound_method.__kwdefaults__)  # revealed: @Todo(specialized non-generic class) | None
 ```
 
 ## Basic method calls on class objects and instances
@@ -181,10 +181,10 @@ class B:
         return "a"
 
 def f(a_or_b: A | B, any_or_a: Any | A):
-    reveal_type(a_or_b.f)  # revealed: <bound method `f` of `A`> | <bound method `f` of `B`>
+    reveal_type(a_or_b.f)  # revealed: (bound method A.f() -> int) | (bound method B.f() -> str)
     reveal_type(a_or_b.f())  # revealed: int | str
 
-    reveal_type(any_or_a.f)  # revealed: Any | <bound method `f` of `A`>
+    reveal_type(any_or_a.f)  # revealed: Any | (bound method A.f() -> int)
     reveal_type(any_or_a.f())  # revealed: Any | int
 ```
 
@@ -198,7 +198,7 @@ python-version = "3.12"
 ```py
 type IntOrStr = int | str
 
-reveal_type(IntOrStr.__or__)  # revealed: <bound method `__or__` of `typing.TypeAliasType`>
+reveal_type(IntOrStr.__or__)  # revealed: bound method typing.TypeAliasType.__or__(right: Any) -> _SpecialForm
 ```
 
 ## Error cases: Calling `__get__` for methods
@@ -270,7 +270,7 @@ class Meta(type):
 class C(metaclass=Meta):
     pass
 
-reveal_type(C.f)  # revealed: <bound method `f` of `Literal[C]`>
+reveal_type(C.f)  # revealed: bound method Literal[C].f(arg: int) -> str
 reveal_type(C.f(1))  # revealed: str
 ```
 
@@ -322,8 +322,8 @@ class C:
     def f(cls: type[C], x: int) -> str:
         return "a"
 
-reveal_type(C.f)  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(C().f)  # revealed: <bound method `f` of `type[C]`>
+reveal_type(C.f)  # revealed: bound method Literal[C].f(x: int) -> str
+reveal_type(C().f)  # revealed: bound method type[C].f(x: int) -> str
 ```
 
 The `cls` method argument is then implicitly passed as the first argument when calling the method:
@@ -350,7 +350,7 @@ class D:
         # This function is wrongly annotated, it should be `type[D]` instead of `D`
         pass
 
-# error: [invalid-argument-type] "Object of type `Literal[D]` cannot be assigned to parameter 1 (`cls`) of bound method `f`; expected type `D`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `D`, found `Literal[D]`"
 D.f()
 ```
 
@@ -360,8 +360,8 @@ When a class method is accessed on a derived class, it is bound to that derived
 class Derived(C):
     pass
 
-reveal_type(Derived.f)  # revealed: <bound method `f` of `Literal[Derived]`>
-reveal_type(Derived().f)  # revealed: <bound method `f` of `type[Derived]`>
+reveal_type(Derived.f)  # revealed: bound method Literal[Derived].f(x: int) -> str
+reveal_type(Derived().f)  # revealed: bound method type[Derived].f(x: int) -> str
 
 reveal_type(Derived.f(1))  # revealed: str
 reveal_type(Derived().f(1))  # revealed: str
@@ -379,26 +379,31 @@ class C:
     @classmethod
     def f(cls): ...
 
-reveal_type(getattr_static(C, "f"))  # revealed: Literal[f]
+reveal_type(getattr_static(C, "f"))  # revealed: def f(cls) -> Unknown
 reveal_type(getattr_static(C, "f").__get__)  # revealed: <method-wrapper `__get__` of `f`>
 ```
 
 But we correctly model how the `classmethod` descriptor works:
 
 ```py
-reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: <bound method `f` of `Literal[C]`>
-reveal_type(getattr_static(C, "f").__get__(C()))  # revealed: <bound method `f` of `type[C]`>
+reveal_type(getattr_static(C, "f").__get__(None, C))  # revealed: bound method Literal[C].f() -> Unknown
+reveal_type(getattr_static(C, "f").__get__(C(), C))  # revealed: bound method Literal[C].f() -> Unknown
+reveal_type(getattr_static(C, "f").__get__(C()))  # revealed: bound method type[C].f() -> Unknown
 ```
 
 The `owner` argument takes precedence over the `instance` argument:
 
 ```py
-reveal_type(getattr_static(C, "f").__get__("dummy", C))  # revealed: <bound method `f` of `Literal[C]`>
+reveal_type(getattr_static(C, "f").__get__("dummy", C))  # revealed: bound method Literal[C].f() -> Unknown
 ```
 
 ### Classmethods mixed with other decorators
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 When a `@classmethod` is additionally decorated with another decorator, it is still treated as a
 class method:
 
@@ -410,29 +415,19 @@ def does_nothing[T](f: T) -> T:
 
 class C:
     @classmethod
-    # TODO: no error should be emitted here (needs support for generics)
-    # error: [invalid-argument-type]
     @does_nothing
     def f1(cls: type[C], x: int) -> str:
         return "a"
-    # TODO: no error should be emitted here (needs support for generics)
-    # error: [invalid-argument-type]
+
     @does_nothing
     @classmethod
     def f2(cls: type[C], x: int) -> str:
         return "a"
 
-# TODO: All of these should be `str` (and not emit an error), once we support generics
-
-# error: [call-non-callable]
-reveal_type(C.f1(1))  # revealed: Unknown
-# error: [call-non-callable]
-reveal_type(C().f1(1))  # revealed: Unknown
-
-# error: [call-non-callable]
-reveal_type(C.f2(1))  # revealed: Unknown
-# error: [call-non-callable]
-reveal_type(C().f2(1))  # revealed: Unknown
+reveal_type(C.f1(1))  # revealed: str
+reveal_type(C().f1(1))  # revealed: str
+reveal_type(C.f2(1))  # revealed: str
+reveal_type(C().f2(1))  # revealed: str
 ```
 
 [functions and methods]: https://docs.python.org/3/howto/descriptor.html#functions-and-methods

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

@@ -0,0 +1,50 @@
+# `str.startswith`
+
+We special-case `str.startswith` to allow inference of precise Boolean literal types, because those
+are used in [`sys.platform` checks].
+
+```py
+reveal_type("abc".startswith(""))  # revealed: Literal[True]
+reveal_type("abc".startswith("a"))  # revealed: Literal[True]
+reveal_type("abc".startswith("ab"))  # revealed: Literal[True]
+reveal_type("abc".startswith("abc"))  # revealed: Literal[True]
+
+reveal_type("abc".startswith("abcd"))  # revealed: Literal[False]
+reveal_type("abc".startswith("bc"))  # revealed: Literal[False]
+
+reveal_type("AbC".startswith(""))  # revealed: Literal[True]
+reveal_type("AbC".startswith("A"))  # revealed: Literal[True]
+reveal_type("AbC".startswith("Ab"))  # revealed: Literal[True]
+reveal_type("AbC".startswith("AbC"))  # revealed: Literal[True]
+
+reveal_type("AbC".startswith("a"))  # revealed: Literal[False]
+reveal_type("AbC".startswith("aB"))  # revealed: Literal[False]
+
+reveal_type("".startswith(""))  # revealed: Literal[True]
+
+reveal_type("".startswith(" "))  # revealed: Literal[False]
+```
+
+Make sure that we fall back to `bool` for more complex cases:
+
+```py
+reveal_type("abc".startswith("b", 1))  # revealed: bool
+reveal_type("abc".startswith("bc", 1, 3))  # revealed: bool
+
+reveal_type("abc".startswith(("a", "x")))  # revealed: bool
+```
+
+And similiarly, we should still infer `bool` if the instance or the prefix are not string literals:
+
+```py
+from typing_extensions import LiteralString
+
+def _(string_instance: str, literalstring: LiteralString):
+    reveal_type(string_instance.startswith("a"))  # revealed: bool
+    reveal_type(literalstring.startswith("a"))  # revealed: bool
+
+    reveal_type("a".startswith(string_instance))  # revealed: bool
+    reveal_type("a".startswith(literalstring))  # revealed: bool
+```
+
+[`sys.platform` checks]: https://docs.python.org/3/library/sys.html#sys.platform

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

@@ -20,7 +20,7 @@ class C:
 def _(subclass_of_c: type[C]):
     reveal_type(subclass_of_c(1))  # revealed: C
 
-    # error: [invalid-argument-type] "Object of type `Literal["a"]` cannot be assigned to parameter 2 (`x`) of bound method `__init__`; expected type `int`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["a"]`"
     reveal_type(subclass_of_c("a"))  # revealed: C
     # error: [missing-argument] "No argument provided for required parameter `x` of bound method `__init__`"
     reveal_type(subclass_of_c())  # revealed: C

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

@@ -94,7 +94,7 @@ def _(flag: bool):
     else:
         f = f2
 
-    # error: [invalid-argument-type] "Object of type `Literal[3]` cannot be assigned to parameter 1 (`a`) of function `f2`; expected type `str`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `str`, found `Literal[3]`"
     x = f(3)
     reveal_type(x)  # revealed: int | str
 ```
@@ -175,3 +175,41 @@ def _(flag: bool):
     # error: [conflicting-argument-forms] "Argument is used as both a value and a type form in call"
     reveal_type(f(int))  # revealed: str | Literal[True]
 ```
+
+## Size limit on unions of literals
+
+Beyond a certain size, large unions of literal types collapse to their nearest super-type (`int`,
+`bytes`, `str`).
+
+```py
+from typing import Literal
+
+def _(literals_2: Literal[0, 1], b: bool, flag: bool):
+    literals_4 = 2 * literals_2 + literals_2  # Literal[0, 1, 2, 3]
+    literals_16 = 4 * literals_4 + literals_4  # Literal[0, 1, .., 15]
+    literals_64 = 4 * literals_16 + literals_4  # Literal[0, 1, .., 63]
+    literals_128 = 2 * literals_64 + literals_2  # Literal[0, 1, .., 127]
+
+    # Going beyond the MAX_UNION_LITERALS limit (currently 200):
+    literals_256 = 16 * literals_16 + literals_16
+    reveal_type(literals_256)  # revealed: int
+
+    # Going beyond the limit when another type is already part of the union
+    bool_and_literals_128 = b if flag else literals_128  # bool | Literal[0, 1, ..., 127]
+    literals_128_shifted = literals_128 + 128  # Literal[128, 129, ..., 255]
+
+    # Now union the two:
+    reveal_type(bool_and_literals_128 if flag else literals_128_shifted)  # revealed: int
+```
+
+## Simplifying gradually-equivalent types
+
+If two types are gradually equivalent, we can keep just one of them in a union:
+
+```py
+from typing import Any, Union
+from knot_extensions import Intersection, Not
+
+def _(x: Union[Intersection[Any, Not[int]], Intersection[Any, Not[int]]]):
+    reveal_type(x)  # revealed: Any & ~int
+```

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

@@ -0,0 +1,410 @@
+# Super
+
+Python defines the terms *bound super object* and *unbound super object*.
+
+An **unbound super object** is created when `super` is called with only one argument. (e.g.
+`super(A)`). This object may later be bound using the `super.__get__` method. However, this form is
+rarely used in practice.
+
+A **bound super object** is created either by calling `super(pivot_class, owner)` or by using the
+implicit form `super()`, where both the pivot class and the owner are inferred. This is the most
+common usage.
+
+## Basic Usage
+
+### Explicit Super Object
+
+`super(pivot_class, owner)` performs attribute lookup along the MRO, starting immediately after the
+specified pivot class.
+
+```py
+class A:
+    def a(self): ...
+    aa: int = 1
+
+class B(A):
+    def b(self): ...
+    bb: int = 2
+
+class C(B):
+    def c(self): ...
+    cc: int = 3
+
+reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[B], Literal[A], Literal[object]]
+
+super(C, C()).a
+super(C, C()).b
+# error: [unresolved-attribute] "Type `<super: Literal[C], C>` has no attribute `c`"
+super(C, C()).c
+
+super(B, C()).a
+# error: [unresolved-attribute] "Type `<super: Literal[B], C>` has no attribute `b`"
+super(B, C()).b
+# error: [unresolved-attribute] "Type `<super: Literal[B], C>` has no attribute `c`"
+super(B, C()).c
+
+# error: [unresolved-attribute] "Type `<super: Literal[A], C>` has no attribute `a`"
+super(A, C()).a
+# error: [unresolved-attribute] "Type `<super: Literal[A], C>` has no attribute `b`"
+super(A, C()).b
+# error: [unresolved-attribute] "Type `<super: Literal[A], C>` has no attribute `c`"
+super(A, C()).c
+
+reveal_type(super(C, C()).a)  # revealed: bound method C.a() -> Unknown
+reveal_type(super(C, C()).b)  # revealed: bound method C.b() -> Unknown
+reveal_type(super(C, C()).aa)  # revealed: int
+reveal_type(super(C, C()).bb)  # revealed: int
+```
+
+### Implicit Super Object
+
+The implicit form `super()` is same as `super(__class__, <first argument>)`. The `__class__` refers
+to the class that contains the function where `super()` is used. The first argument refers to the
+current method’s first parameter (typically `self` or `cls`).
+
+```py
+from __future__ import annotations
+
+class A:
+    def __init__(self, a: int): ...
+    @classmethod
+    def f(cls): ...
+
+class B(A):
+    def __init__(self, a: int):
+        # TODO: Once `Self` is supported, this should be `<super: Literal[B], B>`
+        reveal_type(super())  # revealed: <super: Literal[B], Unknown>
+        super().__init__(a)
+
+    @classmethod
+    def f(cls):
+        # TODO: Once `Self` is supported, this should be `<super: Literal[B], Literal[B]>`
+        reveal_type(super())  # revealed: <super: Literal[B], Unknown>
+        super().f()
+
+super(B, B(42)).__init__(42)
+super(B, B).f()
+```
+
+### Unbound Super Object
+
+Calling `super(cls)` without a second argument returns an *unbound super object*. This is treated as
+a plain `super` instance and does not support name lookup via the MRO.
+
+```py
+class A:
+    a: int = 42
+
+class B(A): ...
+
+reveal_type(super(B))  # revealed: super
+
+# error: [unresolved-attribute] "Type `super` has no attribute `a`"
+super(B).a
+```
+
+## Attribute Assignment
+
+`super()` objects do not allow attribute assignment — even if the attribute is resolved
+successfully.
+
+```py
+class A:
+    a: int = 3
+
+class B(A): ...
+
+reveal_type(super(B, B()).a)  # revealed: int
+# error: [invalid-assignment] "Cannot assign to attribute `a` on type `<super: Literal[B], B>`"
+super(B, B()).a = 3
+# error: [invalid-assignment] "Cannot assign to attribute `a` on type `super`"
+super(B).a = 5
+```
+
+## Dynamic Types
+
+If any of the arguments is dynamic, we cannot determine the MRO to traverse. When accessing a
+member, it should effectively behave like a dynamic type.
+
+```py
+class A:
+    a: int = 1
+
+def f(x):
+    reveal_type(x)  # revealed: Unknown
+
+    reveal_type(super(x, x))  # revealed: <super: Unknown, Unknown>
+    reveal_type(super(A, x))  # revealed: <super: Literal[A], Unknown>
+    reveal_type(super(x, A()))  # revealed: <super: Unknown, A>
+
+    reveal_type(super(x, x).a)  # revealed: Unknown
+    reveal_type(super(A, x).a)  # revealed: Unknown
+    reveal_type(super(x, A()).a)  # revealed: Unknown
+```
+
+## Implicit `super()` in Complex Structure
+
+```py
+from __future__ import annotations
+
+class A:
+    def test(self):
+        reveal_type(super())  # revealed: <super: Literal[A], Unknown>
+
+    class B:
+        def test(self):
+            reveal_type(super())  # revealed: <super: Literal[B], Unknown>
+
+            class C(A.B):
+                def test(self):
+                    reveal_type(super())  # revealed: <super: Literal[C], Unknown>
+
+            def inner(t: C):
+                reveal_type(super())  # revealed: <super: Literal[B], C>
+            lambda x: reveal_type(super())  # revealed: <super: Literal[B], Unknown>
+```
+
+## Built-ins and Literals
+
+```py
+reveal_type(super(bool, True))  # revealed: <super: Literal[bool], bool>
+reveal_type(super(bool, bool()))  # revealed: <super: Literal[bool], bool>
+reveal_type(super(int, bool()))  # revealed: <super: Literal[int], bool>
+reveal_type(super(int, 3))  # revealed: <super: Literal[int], int>
+reveal_type(super(str, ""))  # revealed: <super: Literal[str], str>
+```
+
+## Descriptor Behavior with Super
+
+Accessing attributes through `super` still invokes descriptor protocol. However, the behavior can
+differ depending on whether the second argument to `super` is a class or an instance.
+
+```py
+class A:
+    def a1(self): ...
+    @classmethod
+    def a2(cls): ...
+
+class B(A): ...
+
+# A.__dict__["a1"].__get__(B(), B)
+reveal_type(super(B, B()).a1)  # revealed: bound method B.a1() -> Unknown
+# A.__dict__["a2"].__get__(B(), B)
+reveal_type(super(B, B()).a2)  # revealed: bound method type[B].a2() -> Unknown
+
+# A.__dict__["a1"].__get__(None, B)
+reveal_type(super(B, B).a1)  # revealed: def a1(self) -> Unknown
+# A.__dict__["a2"].__get__(None, B)
+reveal_type(super(B, B).a2)  # revealed: bound method Literal[B].a2() -> Unknown
+```
+
+## Union of Supers
+
+When the owner is a union type, `super()` is built separately for each branch, and the resulting
+super objects are combined into a union.
+
+```py
+class A: ...
+
+class B:
+    b: int = 42
+
+class C(A, B): ...
+class D(B, A): ...
+
+def f(x: C | D):
+    reveal_type(C.__mro__)  # revealed: tuple[Literal[C], Literal[A], Literal[B], Literal[object]]
+    reveal_type(D.__mro__)  # revealed: tuple[Literal[D], Literal[B], Literal[A], Literal[object]]
+
+    s = super(A, x)
+    reveal_type(s)  # revealed: <super: Literal[A], C> | <super: Literal[A], D>
+
+    # error: [possibly-unbound-attribute] "Attribute `b` on type `<super: Literal[A], C> | <super: Literal[A], D>` is possibly unbound"
+    s.b
+
+def f(flag: bool):
+    x = str() if flag else str("hello")
+    reveal_type(x)  # revealed: Literal["", "hello"]
+    reveal_type(super(str, x))  # revealed: <super: Literal[str], str>
+
+def f(x: int | str):
+    # error: [invalid-super-argument] "`str` is not an instance or subclass of `Literal[int]` in `super(Literal[int], str)` call"
+    super(int, x)
+```
+
+Even when `super()` is constructed separately for each branch of a union, it should behave correctly
+in all cases.
+
+```py
+def f(flag: bool):
+    if flag:
+        class A:
+            x = 1
+            y: int = 1
+
+            a: str = "hello"
+
+        class B(A): ...
+        s = super(B, B())
+    else:
+        class C:
+            x = 2
+            y: int | str = "test"
+
+        class D(C): ...
+        s = super(D, D())
+
+    reveal_type(s)  # revealed: <super: Literal[B], B> | <super: Literal[D], D>
+
+    reveal_type(s.x)  # revealed: Unknown | Literal[1, 2]
+    reveal_type(s.y)  # revealed: int | str
+
+    # error: [possibly-unbound-attribute] "Attribute `a` on type `<super: Literal[B], B> | <super: Literal[D], D>` is possibly unbound"
+    reveal_type(s.a)  # revealed: str
+```
+
+## Supers with Generic Classes
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+from knot_extensions import TypeOf, static_assert, is_subtype_of
+
+class A[T]:
+    def f(self, a: T) -> T:
+        return a
+
+class B[T](A[T]):
+    def f(self, b: T) -> T:
+        return super().f(b)
+```
+
+## Invalid Usages
+
+### Unresolvable `super()` Calls
+
+If an appropriate class and argument cannot be found, a runtime error will occur.
+
+```py
+from __future__ import annotations
+
+# error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+reveal_type(super())  # revealed: Unknown
+
+def f():
+    # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+    super()
+
+# No first argument in its scope
+class A:
+    # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+    s = super()
+
+    def f(self):
+        def g():
+            # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+            super()
+        # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+        lambda: super()
+
+        # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+        (super() for _ in range(10))
+
+    @staticmethod
+    def h():
+        # error: [unavailable-implicit-super-arguments] "Cannot determine implicit arguments for 'super()' in this context"
+        super()
+```
+
+### Failing Condition Checks
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+`super()` requires its first argument to be a valid class, and its second argument to be either an
+instance or a subclass of the first. If either condition is violated, a `TypeError` is raised at
+runtime.
+
+```py
+def f(x: int):
+    # error: [invalid-super-argument] "`int` is not a valid class"
+    super(x, x)
+
+    type IntAlias = int
+    # error: [invalid-super-argument] "`typing.TypeAliasType` is not a valid class"
+    super(IntAlias, 0)
+
+# error: [invalid-super-argument] "`Literal[""]` is not an instance or subclass of `Literal[int]` in `super(Literal[int], Literal[""])` call"
+# revealed: Unknown
+reveal_type(super(int, str()))
+
+# error: [invalid-super-argument] "`Literal[str]` is not an instance or subclass of `Literal[int]` in `super(Literal[int], Literal[str])` call"
+# revealed: Unknown
+reveal_type(super(int, str))
+
+class A: ...
+class B(A): ...
+
+# error: [invalid-super-argument] "`A` is not an instance or subclass of `Literal[B]` in `super(Literal[B], A)` call"
+# revealed: Unknown
+reveal_type(super(B, A()))
+
+# error: [invalid-super-argument] "`object` is not an instance or subclass of `Literal[B]` in `super(Literal[B], object)` call"
+# revealed: Unknown
+reveal_type(super(B, object()))
+
+# error: [invalid-super-argument] "`Literal[A]` is not an instance or subclass of `Literal[B]` in `super(Literal[B], Literal[A])` call"
+# revealed: Unknown
+reveal_type(super(B, A))
+
+# error: [invalid-super-argument] "`Literal[object]` is not an instance or subclass of `Literal[B]` in `super(Literal[B], Literal[object])` call"
+# revealed: Unknown
+reveal_type(super(B, object))
+
+super(object, object()).__class__
+```
+
+### Instance Member Access via `super`
+
+Accessing instance members through `super()` is not allowed.
+
+```py
+from __future__ import annotations
+
+class A:
+    def __init__(self, a: int):
+        self.a = a
+
+class B(A):
+    def __init__(self, a: int):
+        super().__init__(a)
+        # TODO: Once `Self` is supported, this should raise `unresolved-attribute` error
+        super().a
+
+# error: [unresolved-attribute] "Type `<super: Literal[B], B>` has no attribute `a`"
+super(B, B(42)).a
+```
+
+### Dunder Method Resolution
+
+Dunder methods defined in the `owner` (from `super(pivot_class, owner)`) should not affect the super
+object itself. In other words, `super` should not be treated as if it inherits attributes of the
+`owner`.
+
+```py
+class A:
+    def __getitem__(self, key: int) -> int:
+        return 42
+
+class B(A): ...
+
+reveal_type(A()[0])  # revealed: int
+reveal_type(super(B, B()).__getitem__)  # revealed: bound method B.__getitem__(key: int) -> int
+# error: [non-subscriptable] "Cannot subscript object of type `<super: Literal[B], B>` with no `__getitem__` method"
+super(B, B())[0]
+```

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

@@ -50,13 +50,17 @@ reveal_type(x)  # revealed: LiteralString
 if x != "abc":
     reveal_type(x)  # revealed: LiteralString & ~Literal["abc"]
 
-    reveal_type(x == "abc")  # revealed: Literal[False]
-    reveal_type("abc" == x)  # revealed: Literal[False]
+    # TODO: This should be `Literal[False]`
+    reveal_type(x == "abc")  # revealed: bool
+    # TODO: This should be `Literal[False]`
+    reveal_type("abc" == x)  # revealed: bool
     reveal_type(x == "something else")  # revealed: bool
     reveal_type("something else" == x)  # revealed: bool
 
-    reveal_type(x != "abc")  # revealed: Literal[True]
-    reveal_type("abc" != x)  # revealed: Literal[True]
+    # TODO: This should be `Literal[True]`
+    reveal_type(x != "abc")  # revealed: bool
+    # TODO: This should be `Literal[True]`
+    reveal_type("abc" != x)  # revealed: bool
     reveal_type(x != "something else")  # revealed: bool
     reveal_type("something else" != x)  # revealed: bool
 
@@ -79,10 +83,10 @@ def _(x: int):
     if x != 1:
         reveal_type(x)  # revealed: int & ~Literal[1]
 
-        reveal_type(x != 1)  # revealed: Literal[True]
+        reveal_type(x != 1)  # revealed: bool
         reveal_type(x != 2)  # revealed: bool
 
-        reveal_type(x == 1)  # revealed: Literal[False]
+        reveal_type(x == 1)  # revealed: bool
         reveal_type(x == 2)  # revealed: bool
 ```
 

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

@@ -1,5 +1,10 @@
 # Pattern matching
 
+```toml
+[environment]
+python-version = "3.10"
+```
+
 ## With wildcard
 
 ```py

crates/red_knot_python_semantic/resources/mdtest/dataclasses.md

@@ -0,0 +1,731 @@
+# Dataclasses
+
+## Basic
+
+Decorating a class with `@dataclass` is a convenient way to add special methods such as `__init__`,
+`__repr__`, and `__eq__` to a class. The following example shows the basic usage of the `@dataclass`
+decorator. By default, only the three mentioned methods are generated.
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Person:
+    name: str
+    age: int | None = None
+
+alice1 = Person("Alice", 30)
+alice2 = Person(name="Alice", age=30)
+alice3 = Person(age=30, name="Alice")
+alice4 = Person("Alice", age=30)
+
+reveal_type(alice1)  # revealed: Person
+reveal_type(type(alice1))  # revealed: type[Person]
+
+reveal_type(alice1.name)  # revealed: str
+reveal_type(alice1.age)  # revealed: int | None
+
+reveal_type(repr(alice1))  # revealed: str
+
+reveal_type(alice1 == alice2)  # revealed: bool
+reveal_type(alice1 == "Alice")  # revealed: bool
+
+bob = Person("Bob")
+bob2 = Person("Bob", None)
+bob3 = Person(name="Bob")
+bob4 = Person(name="Bob", age=None)
+```
+
+The signature of the `__init__` method is generated based on the classes attributes. The following
+calls are not valid:
+
+```py
+# error: [missing-argument]
+Person()
+
+# error: [too-many-positional-arguments]
+Person("Eve", 20, "too many arguments")
+
+# error: [invalid-argument-type]
+Person("Eve", "string instead of int")
+
+# error: [invalid-argument-type]
+# error: [invalid-argument-type]
+Person(20, "Eve")
+```
+
+## Signature of `__init__`
+
+TODO: All of the following tests are missing the `self` argument in the `__init__` signature.
+
+Declarations in the class body are used to generate the signature of the `__init__` method. If the
+attributes are not just declarations, but also bindings, the type inferred from bindings is used as
+the default value.
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class D:
+    x: int
+    y: str = "default"
+    z: int | None = 1 + 2
+
+reveal_type(D.__init__)  # revealed: (x: int, y: str = Literal["default"], z: int | None = Literal[3]) -> None
+```
+
+This also works if the declaration and binding are split:
+
+```py
+@dataclass
+class D:
+    x: int | None
+    x = None
+
+reveal_type(D.__init__)  # revealed: (x: int | None = None) -> None
+```
+
+Non-fully static types are handled correctly:
+
+```py
+from typing import Any
+
+@dataclass
+class C:
+    x: Any
+    y: int | Any
+    z: tuple[int, Any]
+
+reveal_type(C.__init__)  # revealed: (x: Any, y: int | Any, z: tuple[int, Any]) -> None
+```
+
+Variables without annotations are ignored:
+
+```py
+@dataclass
+class D:
+    x: int
+    y = 1
+
+reveal_type(D.__init__)  # revealed: (x: int) -> None
+```
+
+If attributes without default values are declared after attributes with default values, a
+`TypeError` will be raised at runtime. Ideally, we would emit a diagnostic in that case:
+
+```py
+@dataclass
+class D:
+    x: int = 1
+    # TODO: this should be an error: field without default defined after field with default
+    y: str
+```
+
+Pure class attributes (`ClassVar`) are not included in the signature of `__init__`:
+
+```py
+from typing import ClassVar
+
+@dataclass
+class D:
+    x: int
+    y: ClassVar[str] = "default"
+    z: bool
+
+reveal_type(D.__init__)  # revealed: (x: int, z: bool) -> None
+
+d = D(1, True)
+reveal_type(d.x)  # revealed: int
+reveal_type(d.y)  # revealed: str
+reveal_type(d.z)  # revealed: bool
+```
+
+Function declarations do not affect the signature of `__init__`:
+
+```py
+@dataclass
+class D:
+    x: int
+
+    def y(self) -> str:
+        return ""
+
+reveal_type(D.__init__)  # revealed: (x: int) -> None
+```
+
+And neither do nested class declarations:
+
+```py
+@dataclass
+class D:
+    x: int
+
+    class Nested:
+        y: str
+
+reveal_type(D.__init__)  # revealed: (x: int) -> None
+```
+
+But if there is a variable annotation with a function or class literal type, the signature of
+`__init__` will include this field:
+
+```py
+from knot_extensions import TypeOf
+
+class SomeClass: ...
+
+def some_function() -> None: ...
+@dataclass
+class D:
+    function_literal: TypeOf[some_function]
+    class_literal: TypeOf[SomeClass]
+    class_subtype_of: type[SomeClass]
+
+# revealed: (function_literal: def some_function() -> None, class_literal: Literal[SomeClass], class_subtype_of: type[SomeClass]) -> None
+reveal_type(D.__init__)
+```
+
+More realistically, dataclasses can have `Callable` attributes:
+
+```py
+from typing import Callable
+
+@dataclass
+class D:
+    c: Callable[[int], str]
+
+reveal_type(D.__init__)  # revealed: (c: (int, /) -> str) -> None
+```
+
+Implicit instance attributes do not affect the signature of `__init__`:
+
+```py
+@dataclass
+class D:
+    x: int
+
+    def f(self, y: str) -> None:
+        self.y: str = y
+
+reveal_type(D(1).y)  # revealed: str
+
+reveal_type(D.__init__)  # revealed: (x: int) -> None
+```
+
+Annotating expressions does not lead to an entry in `__annotations__` at runtime, and so it wouldn't
+be included in the signature of `__init__`. This is a case that we currently don't detect:
+
+```py
+@dataclass
+class D:
+    # (x) is an expression, not a "simple name"
+    (x): int = 1
+
+# TODO: should ideally not include a `x` parameter
+reveal_type(D.__init__)  # revealed: (x: int = Literal[1]) -> None
+```
+
+## `@dataclass` calls with arguments
+
+The `@dataclass` decorator can take several arguments to customize the existence of the generated
+methods. The following test makes sure that we still treat the class as a dataclass if (the default)
+arguments are passed in:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(init=True, repr=True, eq=True)
+class Person:
+    name: str
+    age: int | None = None
+
+alice = Person("Alice", 30)
+reveal_type(repr(alice))  # revealed: str
+reveal_type(alice == alice)  # revealed: bool
+```
+
+If `init` is set to `False`, no `__init__` method is generated:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(init=False)
+class C:
+    x: int
+
+C()  # Okay
+
+# error: [too-many-positional-arguments]
+C(1)
+
+repr(C())
+
+C() == C()
+```
+
+## Other dataclass parameters
+
+### `repr`
+
+A custom `__repr__` method is generated by default. It can be disabled by passing `repr=False`, but
+in that case `__repr__` is still available via `object.__repr__`:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(repr=False)
+class WithoutRepr:
+    x: int
+
+reveal_type(WithoutRepr(1).__repr__)  # revealed: bound method WithoutRepr.__repr__() -> str
+```
+
+### `eq`
+
+The same is true for `__eq__`. Setting `eq=False` disables the generated `__eq__` method, but
+`__eq__` is still available via `object.__eq__`:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(eq=False)
+class WithoutEq:
+    x: int
+
+reveal_type(WithoutEq(1) == WithoutEq(2))  # revealed: bool
+```
+
+### `order`
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+`order` is set to `False` by default. If `order=True`, `__lt__`, `__le__`, `__gt__`, and `__ge__`
+methods will be generated:
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class WithoutOrder:
+    x: int
+
+WithoutOrder(1) < WithoutOrder(2)  # error: [unsupported-operator]
+WithoutOrder(1) <= WithoutOrder(2)  # error: [unsupported-operator]
+WithoutOrder(1) > WithoutOrder(2)  # error: [unsupported-operator]
+WithoutOrder(1) >= WithoutOrder(2)  # error: [unsupported-operator]
+
+@dataclass(order=True)
+class WithOrder:
+    x: int
+
+WithOrder(1) < WithOrder(2)
+WithOrder(1) <= WithOrder(2)
+WithOrder(1) > WithOrder(2)
+WithOrder(1) >= WithOrder(2)
+```
+
+Comparisons are only allowed for `WithOrder` instances:
+
+```py
+WithOrder(1) < 2  # error: [unsupported-operator]
+WithOrder(1) <= 2  # error: [unsupported-operator]
+WithOrder(1) > 2  # error: [unsupported-operator]
+WithOrder(1) >= 2  # error: [unsupported-operator]
+```
+
+This also works for generic dataclasses:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(order=True)
+class GenericWithOrder[T]:
+    x: T
+
+GenericWithOrder[int](1) < GenericWithOrder[int](1)
+
+GenericWithOrder[int](1) < GenericWithOrder[str]("a")  # error: [unsupported-operator]
+```
+
+If a class already defines one of the comparison methods, a `TypeError` is raised at runtime.
+Ideally, we would emit a diagnostic in that case:
+
+```py
+@dataclass(order=True)
+class AlreadyHasCustomDunderLt:
+    x: int
+
+    # TODO: Ideally, we would emit a diagnostic here
+    def __lt__(self, other: object) -> bool:
+        return False
+```
+
+### `unsafe_hash`
+
+To do
+
+### `frozen`
+
+To do
+
+### `match_args`
+
+To do
+
+### `kw_only`
+
+To do
+
+### `slots`
+
+To do
+
+### `weakref_slot`
+
+To do
+
+## Inheritance
+
+### Normal class inheriting from a dataclass
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+    x: int
+
+class Derived(Base): ...
+
+d = Derived(1)  # OK
+reveal_type(d.x)  # revealed: int
+```
+
+### Dataclass inheriting from normal class
+
+```py
+from dataclasses import dataclass
+
+class Base:
+    x: int = 1
+
+@dataclass
+class Derived(Base):
+    y: str
+
+d = Derived("a")
+
+# error: [too-many-positional-arguments]
+# error: [invalid-argument-type]
+Derived(1, "a")
+```
+
+### Dataclass inheriting from another dataclass
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+    x: int
+    y: str
+
+@dataclass
+class Derived(Base):
+    z: bool
+
+d = Derived(1, "a", True)  # OK
+
+reveal_type(d.x)  # revealed: int
+reveal_type(d.y)  # revealed: str
+reveal_type(d.z)  # revealed: bool
+
+# error: [missing-argument]
+Derived(1, "a")
+
+# error: [missing-argument]
+Derived(True)
+```
+
+### Overwriting attributes from base class
+
+The following example comes from the
+[Python documentation](https://docs.python.org/3/library/dataclasses.html#inheritance). The `x`
+attribute appears just once in the `__init__` signature, and the default value is taken from the
+derived class
+
+```py
+from dataclasses import dataclass
+from typing import Any
+
+@dataclass
+class Base:
+    x: Any = 15.0
+    y: int = 0
+
+@dataclass
+class C(Base):
+    z: int = 10
+    x: int = 15
+
+reveal_type(C.__init__)  # revealed: (x: int = Literal[15], y: int = Literal[0], z: int = Literal[10]) -> None
+```
+
+## Generic dataclasses
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class DataWithDescription[T]:
+    data: T
+    description: str
+
+reveal_type(DataWithDescription[int])  # revealed: Literal[DataWithDescription[int]]
+
+d_int = DataWithDescription[int](1, "description")  # OK
+reveal_type(d_int.data)  # revealed: int
+reveal_type(d_int.description)  # revealed: str
+
+# error: [invalid-argument-type]
+DataWithDescription[int](None, "description")
+```
+
+## Descriptor-typed fields
+
+### Same type in `__get__` and `__set__`
+
+For the following descriptor, the return type of `__get__` and the type of the `value` parameter in
+`__set__` are the same. The generated `__init__` method takes an argument of this type (instead of
+the type of the descriptor), and the default value is also of this type:
+
+```py
+from typing import overload
+from dataclasses import dataclass
+
+class UppercaseString:
+    _value: str = ""
+
+    def __get__(self, instance: object, owner: None | type) -> str:
+        return self._value
+
+    def __set__(self, instance: object, value: str) -> None:
+        self._value = value.upper()
+
+@dataclass
+class C:
+    upper: UppercaseString = UppercaseString()
+
+reveal_type(C.__init__)  # revealed: (upper: str = str) -> None
+
+c = C("abc")
+reveal_type(c.upper)  # revealed: str
+
+# This is also okay:
+C()
+
+# error: [invalid-argument-type]
+C(1)
+
+# error: [too-many-positional-arguments]
+C("a", "b")
+```
+
+### Different types in `__get__` and `__set__`
+
+In general, the type of the `__init__` parameter is determined by the `value` parameter type of the
+`__set__` method (`str` in the example below). However, the default value is generated by calling
+the descriptor's `__get__` method as if it had been called on the class itself, i.e. passing `None`
+for the `instance` argument.
+
+```py
+from typing import Literal, overload
+from dataclasses import dataclass
+
+class ConvertToLength:
+    _len: int = 0
+
+    @overload
+    def __get__(self, instance: None, owner: type) -> Literal[""]: ...
+    @overload
+    def __get__(self, instance: object, owner: type | None) -> int: ...
+    def __get__(self, instance: object | None, owner: type | None) -> str | int:
+        if instance is None:
+            return ""
+
+        return self._len
+
+    def __set__(self, instance, value: str) -> None:
+        self._len = len(value)
+
+@dataclass
+class C:
+    converter: ConvertToLength = ConvertToLength()
+
+reveal_type(C.__init__)  # revealed: (converter: str = Literal[""]) -> None
+
+c = C("abc")
+reveal_type(c.converter)  # revealed: int
+
+# This is also okay:
+C()
+
+# error: [invalid-argument-type]
+C(1)
+
+# error: [too-many-positional-arguments]
+C("a", "b")
+```
+
+### With overloaded `__set__` method
+
+If the `__set__` method is overloaded, we determine the type for the `__init__` parameter as the
+union of all possible `value` parameter types:
+
+```py
+from typing import overload
+from dataclasses import dataclass
+
+class AcceptsStrAndInt:
+    def __get__(self, instance, owner) -> int:
+        return 0
+
+    @overload
+    def __set__(self, instance: object, value: str) -> None: ...
+    @overload
+    def __set__(self, instance: object, value: int) -> None: ...
+    def __set__(self, instance: object, value) -> None:
+        pass
+
+@dataclass
+class C:
+    field: AcceptsStrAndInt = AcceptsStrAndInt()
+
+reveal_type(C.__init__)  # revealed: (field: str | int = int) -> None
+```
+
+## `dataclasses.field`
+
+To do
+
+## Other special cases
+
+### `dataclasses.dataclass`
+
+We also understand dataclasses if they are decorated with the fully qualified name:
+
+```py
+import dataclasses
+
+@dataclasses.dataclass
+class C:
+    x: str
+
+reveal_type(C.__init__)  # revealed: (x: str) -> None
+```
+
+### Dataclass with custom `__init__` method
+
+If a class already defines `__init__`, it is not replaced by the `dataclass` decorator.
+
+```py
+from dataclasses import dataclass
+
+@dataclass(init=True)
+class C:
+    x: str
+
+    def __init__(self, x: int) -> None:
+        self.x = str(x)
+
+C(1)  # OK
+
+# error: [invalid-argument-type]
+C("a")
+```
+
+Similarly, if we set `init=False`, we still recognize the custom `__init__` method:
+
+```py
+@dataclass(init=False)
+class D:
+    def __init__(self, x: int) -> None:
+        self.x = str(x)
+
+D(1)  # OK
+D()  # error: [missing-argument]
+```
+
+### Accessing instance attributes on the class itself
+
+Just like for normal classes, accessing instance attributes on the class itself is not allowed:
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class C:
+    x: int
+
+# error: [unresolved-attribute] "Attribute `x` can only be accessed on instances, not on the class object `Literal[C]` itself."
+C.x
+```
+
+### Return type of `dataclass(...)`
+
+A call like `dataclass(order=True)` returns a callable itself, which is then used as the decorator.
+We can store the callable in a variable and later use it as a decorator:
+
+```py
+from dataclasses import dataclass
+
+dataclass_with_order = dataclass(order=True)
+
+reveal_type(dataclass_with_order)  # revealed: <decorator produced by dataclasses.dataclass>
+
+@dataclass_with_order
+class C:
+    x: int
+
+C(1) < C(2)  # ok
+```
+
+### Using `dataclass` as a function
+
+To do
+
+## Internals
+
+The `dataclass` decorator returns the class itself. This means that the type of `Person` is `type`,
+and attributes like the MRO are unchanged:
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Person:
+    name: str
+    age: int | None = None
+
+reveal_type(type(Person))  # revealed: Literal[type]
+reveal_type(Person.__mro__)  # revealed: tuple[Literal[Person], Literal[object]]
+```
+
+The generated methods have the following signatures:
+
+```py
+# TODO: `self` is missing here
+reveal_type(Person.__init__)  # revealed: (name: str, age: int | None = None) -> None
+
+reveal_type(Person.__repr__)  # revealed: def __repr__(self) -> str
+
+reveal_type(Person.__eq__)  # revealed: def __eq__(self, value: object, /) -> bool
+```

crates/red_knot_python_semantic/resources/mdtest/decorators.md

@@ -145,10 +145,10 @@ def f(x: int) -> int:
     return x**2
 
 # TODO: Should be `_lru_cache_wrapper[int]`
-reveal_type(f)  # revealed: @Todo(generics)
+reveal_type(f)  # revealed: @Todo(specialized non-generic class)
 
 # TODO: Should be `int`
-reveal_type(f(1))  # revealed: @Todo(generics)
+reveal_type(f(1))  # revealed: @Todo(specialized non-generic class)
 ```
 
 ## Lambdas as decorators
@@ -207,7 +207,7 @@ first argument:
 def wrong_signature(f: int) -> str:
     return "a"
 
-# error: [invalid-argument-type] "Object of type `Literal[f]` cannot be assigned to parameter 1 (`f`) of function `wrong_signature`; expected type `int`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `def f(x) -> Unknown`"
 @wrong_signature
 def f(x): ...
 

crates/red_knot_python_semantic/resources/mdtest/descriptor_protocol.md

@@ -459,11 +459,9 @@ class Descriptor:
 class C:
     d: Descriptor = Descriptor()
 
-# TODO: should be `Literal["called on class object"]
-reveal_type(C.d)  # revealed: LiteralString
+reveal_type(C.d)  # revealed: Literal["called on class object"]
 
-# TODO: should be `Literal["called on instance"]
-reveal_type(C().d)  # revealed: LiteralString
+reveal_type(C().d)  # revealed: Literal["called on instance"]
 ```
 
 ## Descriptor protocol for dunder methods
@@ -563,18 +561,18 @@ from inspect import getattr_static
 def f(x: object) -> str:
     return "a"
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f(x: object) -> str
 reveal_type(f.__get__)  # revealed: <method-wrapper `__get__` of `f`>
-reveal_type(f.__get__(None, type(f)))  # revealed: Literal[f]
+reveal_type(f.__get__(None, type(f)))  # revealed: def f(x: object) -> str
 reveal_type(f.__get__(None, type(f))(1))  # revealed: str
 
 wrapper_descriptor = getattr_static(f, "__get__")
 
 reveal_type(wrapper_descriptor)  # revealed: <wrapper-descriptor `__get__` of `function` objects>
-reveal_type(wrapper_descriptor(f, None, type(f)))  # revealed: Literal[f]
+reveal_type(wrapper_descriptor(f, None, type(f)))  # revealed: def f(x: object) -> str
 
 # Attribute access on the method-wrapper `f.__get__` falls back to `MethodWrapperType`:
-reveal_type(f.__get__.__hash__)  # revealed: <bound method `__hash__` of `MethodWrapperType`>
+reveal_type(f.__get__.__hash__)  # revealed: bound method MethodWrapperType.__hash__() -> int
 
 # Attribute access on the wrapper-descriptor falls back to `WrapperDescriptorType`:
 reveal_type(wrapper_descriptor.__qualname__)  # revealed: str
@@ -587,7 +585,7 @@ class C: ...
 
 bound_method = wrapper_descriptor(f, C(), C)
 
-reveal_type(bound_method)  # revealed: <bound method `f` of `C`>
+reveal_type(bound_method)  # revealed: bound method C.f() -> str
 ```
 
 We can then call it, and the instance of `C` is implicitly passed to the first parameter of `f`

crates/red_knot_python_semantic/resources/mdtest/diagnostics/version_related_syntax_errors.md

@@ -0,0 +1,37 @@
+# Version-related syntax error diagnostics
+
+## `match` statement
+
+The `match` statement was introduced in Python 3.10.
+
+### Before 3.10
+
+<!-- snapshot-diagnostics -->
+
+We should emit a syntax error before 3.10.
+
+```toml
+[environment]
+python-version = "3.9"
+```
+
+```py
+match 2:  # error: 1 [invalid-syntax] "Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)"
+    case 1:
+        print("it's one")
+```
+
+### After 3.10
+
+On or after 3.10, no error should be reported.
+
+```toml
+[environment]
+python-version = "3.10"
+```
+
+```py
+match 2:
+    case 1:
+        print("it's one")
+```

crates/red_knot_python_semantic/resources/mdtest/directives/assert_never.md

@@ -26,6 +26,11 @@ def _(never: Never, any_: Any, unknown: Unknown, flag: bool):
 
 ## Use case: Type narrowing and exhaustiveness checking
 
+```toml
+[environment]
+python-version = "3.10"
+```
+
 `assert_never` can be used in combination with type narrowing as a way to make sure that all cases
 are handled in a series of `isinstance` checks or other narrowing patterns that are supported.
 

crates/red_knot_python_semantic/resources/mdtest/directives/cast.md

@@ -61,7 +61,7 @@ from knot_extensions import Unknown
 
 def f(x: Any, y: Unknown, z: Any | str | int):
     a = cast(dict[str, Any], x)
-    reveal_type(a)  # revealed: @Todo(generics)
+    reveal_type(a)  # revealed: @Todo(specialized non-generic class)
 
     b = cast(Any, y)
     reveal_type(b)  # revealed: Any

crates/red_knot_python_semantic/resources/mdtest/doc/public_type_undeclared_symbols.md

@@ -42,7 +42,7 @@ def f(w: Wrapper) -> None:
     v: int | None = w.value
 
     # This function call is incorrect, because `w.value` could be `None`. We therefore emit the following
-    # error: "`Unknown | None` cannot be assigned to parameter 1 (`i`) of function `accepts_int`; expected type `int`"
+    # error: "Argument to this function is incorrect: Expected `int`, found `Unknown | None`"
     c = accepts_int(w.value)
 ```
 

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

@@ -591,9 +591,9 @@ try:
             reveal_type(x)  # revealed: B | D
         reveal_type(x)  # revealed: B | D
     x = foo
-    reveal_type(x)  # revealed: Literal[foo]
+    reveal_type(x)  # revealed: def foo(param=A) -> Unknown
 except:
-    reveal_type(x)  # revealed: Literal[1] | Literal[foo]
+    reveal_type(x)  # revealed: Literal[1] | (def foo(param=A) -> Unknown)
 
     class Bar:
         x = could_raise_returns_E()
@@ -603,9 +603,9 @@ except:
     reveal_type(x)  # revealed: Literal[Bar]
 finally:
     # TODO: should be `Literal[1] | Literal[foo] | Literal[Bar]`
-    reveal_type(x)  # revealed: Literal[foo] | Literal[Bar]
+    reveal_type(x)  # revealed: (def foo(param=A) -> Unknown) | Literal[Bar]
 
-reveal_type(x)  # revealed: Literal[foo] | Literal[Bar]
+reveal_type(x)  # revealed: (def foo(param=A) -> Unknown) | Literal[Bar]
 ```
 
 [1]: https://astral-sh.notion.site/Exception-handler-control-flow-11348797e1ca80bb8ce1e9aedbbe439d

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

@@ -76,6 +76,11 @@ def g(x: Any = "foo"):
 
 ## Stub functions
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ### In Protocol
 
 ```py

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

@@ -56,6 +56,11 @@ def f() -> int:
 
 ### In Protocol
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 from typing import Protocol, TypeVar
 
@@ -69,8 +74,6 @@ class Baz(Bar):
 T = TypeVar("T")
 
 class Qux(Protocol[T]):
-    # TODO: no error
-    # error: [invalid-return-type]
     def f(self) -> int: ...
 
 class Foo(Protocol):
@@ -85,6 +88,11 @@ class Lorem(t[0]):
 
 ### In abstract method
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 from abc import ABC, abstractmethod
 
@@ -310,7 +318,7 @@ def f(cond: bool) -> str:
     return "hello" if cond else NotImplemented
 
 def f(cond: bool) -> int:
-    # error: [invalid-return-type] "Object of type `Literal["hello"]` is not assignable to return type `int`"
+    # error: [invalid-return-type] "Return type does not match returned value: Expected `int`, found `Literal["hello"]`"
     return "hello" if cond else NotImplemented
 ```
 

crates/red_knot_python_semantic/resources/mdtest/generics/classes.md

@@ -1,5 +1,10 @@
 # Generic classes
 
+```toml
+[environment]
+python-version = "3.13"
+```
+
 ## PEP 695 syntax
 
 TODO: Add a `red_knot_extension` function that asserts whether a function or class is generic.
@@ -40,8 +45,6 @@ from typing import Generic, TypeVar
 
 T = TypeVar("T")
 
-# TODO: no error
-# error: [invalid-base]
 class C(Generic[T]): ...
 ```
 
@@ -81,10 +84,10 @@ class IntSubclass(int): ...
 reveal_type(Bounded[int]())  # revealed: Bounded[int]
 reveal_type(Bounded[IntSubclass]())  # revealed: Bounded[IntSubclass]
 
-# error: [invalid-argument-type] "Object of type `str` cannot be assigned to parameter 1 (`T`) of class `Bounded`; expected type `int`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `str`"
 reveal_type(Bounded[str]())  # revealed: Unknown
 
-# error:  [invalid-argument-type] "Object of type `int | str` cannot be assigned to parameter 1 (`T`) of class `Bounded`; expected type `int`"
+# error:  [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `int | str`"
 reveal_type(Bounded[int | str]())  # revealed: Unknown
 
 reveal_type(BoundedByUnion[int]())  # revealed: BoundedByUnion[int]
@@ -110,7 +113,7 @@ reveal_type(Constrained[str]())  # revealed: Constrained[str]
 # TODO: revealed: Unknown
 reveal_type(Constrained[int | str]())  # revealed: Constrained[int | str]
 
-# error: [invalid-argument-type] "Object of type `object` cannot be assigned to parameter 1 (`T`) of class `Constrained`; expected type `int | str`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int | str`, found `object`"
 reveal_type(Constrained[object]())  # revealed: Unknown
 ```
 
@@ -149,23 +152,102 @@ If a typevar does not provide a default, we use `Unknown`:
 reveal_type(C())  # revealed: C[Unknown]
 ```
 
+## Inferring generic class parameters from constructors
+
 If the type of a constructor parameter is a class typevar, we can use that to infer the type
-parameter:
+parameter. The types inferred from a type context and from a constructor parameter must be
+consistent with each other.
+
+## `__new__` only
 
 ```py
-class E[T]:
-    def __init__(self, x: T) -> None: ...
+class C[T]:
+    def __new__(cls, x: T) -> "C[T]":
+        return object.__new__(cls)
 
-# TODO: revealed: E[int] or E[Literal[1]]
-reveal_type(E(1))  # revealed: E[Unknown]
+reveal_type(C(1))  # revealed: C[Literal[1]]
+
+# error: [invalid-assignment] "Object of type `C[Literal["five"]]` is not assignable to `C[int]`"
+wrong_innards: C[int] = C("five")
 ```
 
-The types inferred from a type context and from a constructor parameter must be consistent with each
-other:
+## `__init__` only
 
 ```py
-# TODO: error: [invalid-argument-type]
-wrong_innards: E[int] = E("five")
+class C[T]:
+    def __init__(self, x: T) -> None: ...
+
+reveal_type(C(1))  # revealed: C[Literal[1]]
+
+# error: [invalid-assignment] "Object of type `C[Literal["five"]]` is not assignable to `C[int]`"
+wrong_innards: C[int] = C("five")
+```
+
+## Identical `__new__` and `__init__` signatures
+
+```py
+class C[T]:
+    def __new__(cls, x: T) -> "C[T]":
+        return object.__new__(cls)
+
+    def __init__(self, x: T) -> None: ...
+
+reveal_type(C(1))  # revealed: C[Literal[1]]
+
+# error: [invalid-assignment] "Object of type `C[Literal["five"]]` is not assignable to `C[int]`"
+wrong_innards: C[int] = C("five")
+```
+
+## Compatible `__new__` and `__init__` signatures
+
+```py
+class C[T]:
+    def __new__(cls, *args, **kwargs) -> "C[T]":
+        return object.__new__(cls)
+
+    def __init__(self, x: T) -> None: ...
+
+reveal_type(C(1))  # revealed: C[Literal[1]]
+
+# error: [invalid-assignment] "Object of type `C[Literal["five"]]` is not assignable to `C[int]`"
+wrong_innards: C[int] = C("five")
+
+class D[T]:
+    def __new__(cls, x: T) -> "D[T]":
+        return object.__new__(cls)
+
+    def __init__(self, *args, **kwargs) -> None: ...
+
+reveal_type(D(1))  # revealed: D[Literal[1]]
+
+# error: [invalid-assignment] "Object of type `D[Literal["five"]]` is not assignable to `D[int]`"
+wrong_innards: D[int] = D("five")
+```
+
+## `__init__` is itself generic
+
+TODO: These do not currently work yet, because we don't correctly model the nested generic contexts.
+
+```py
+class C[T]:
+    def __init__[S](self, x: T, y: S) -> None: ...
+
+# TODO: no error
+# TODO: revealed: C[Literal[1]]
+# error: [invalid-argument-type]
+reveal_type(C(1, 1))  # revealed: C[Unknown]
+# TODO: no error
+# TODO: revealed: C[Literal[1]]
+# error: [invalid-argument-type]
+reveal_type(C(1, "string"))  # revealed: C[Unknown]
+# TODO: no error
+# TODO: revealed: C[Literal[1]]
+# error: [invalid-argument-type]
+reveal_type(C(1, True))  # revealed: C[Unknown]
+
+# TODO: [invalid-assignment] "Object of type `C[Literal["five"]]` is not assignable to `C[int]`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `S`, found `Literal[1]`"
+wrong_innards: C[int] = C("five", 1)
 ```
 
 ## Generic subclass
@@ -200,10 +282,7 @@ class C[T]:
     def cannot_shadow_class_typevar[T](self, t: T): ...
 
 c: C[int] = C[int]()
-# TODO: no error
-# TODO: revealed: str or Literal["string"]
-# error: [invalid-argument-type]
-reveal_type(c.method("string"))  # revealed: U
+reveal_type(c.method("string"))  # revealed: Literal["string"]
 ```
 
 ## Cyclic class definition

crates/red_knot_python_semantic/resources/mdtest/generics/functions.md

@@ -1,5 +1,10 @@
 # Generic functions
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ## Typevar must be used at least twice
 
 If you're only using a typevar for a single parameter, you don't need the typevar — just use
@@ -43,33 +48,14 @@ def absurd[T]() -> T:
 If the type of a generic function parameter is a typevar, then we can infer what type that typevar
 is bound to at each call site.
 
-TODO: Note that some of the TODO revealed types have two options, since we haven't decided yet
-whether we want to infer a more specific `Literal` type where possible, or use heuristics to weaken
-the inferred type to e.g. `int`.
-
 ```py
 def f[T](x: T) -> T:
     return x
 
-# TODO: no error
-# TODO: revealed: int or Literal[1]
-# error: [invalid-argument-type]
-reveal_type(f(1))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: float
-# error: [invalid-argument-type]
-reveal_type(f(1.0))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: bool or Literal[true]
-# error: [invalid-argument-type]
-reveal_type(f(True))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: str or Literal["string"]
-# error: [invalid-argument-type]
-reveal_type(f("string"))  # revealed: T
+reveal_type(f(1))  # revealed: Literal[1]
+reveal_type(f(1.0))  # revealed: float
+reveal_type(f(True))  # revealed: Literal[True]
+reveal_type(f("string"))  # revealed: Literal["string"]
 ```
 
 ## Inferring “deep” generic parameter types
@@ -82,7 +68,7 @@ def f[T](x: list[T]) -> T:
     return x[0]
 
 # TODO: revealed: float
-reveal_type(f([1.0, 2.0]))  # revealed: T
+reveal_type(f([1.0, 2.0]))  # revealed: Unknown
 ```
 
 ## Typevar constraints
@@ -93,7 +79,6 @@ in the function.
 
 ```py
 def good_param[T: int](x: T) -> None:
-    # TODO: revealed: T & int
     reveal_type(x)  # revealed: T
 ```
 
@@ -107,7 +92,7 @@ def good_return[T: int](x: T) -> T:
     return x
 
 def bad_return[T: int](x: T) -> T:
-    # error: [invalid-return-type] "Object of type `int` is not assignable to return type `T`"
+    # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `int`"
     return x + 1
 ```
 
@@ -120,7 +105,7 @@ def different_types[T, S](cond: bool, t: T, s: S) -> T:
     if cond:
         return t
     else:
-        # error: [invalid-return-type] "Object of type `S` is not assignable to return type `T`"
+        # error: [invalid-return-type] "Return type does not match returned value: Expected `T`, found `S`"
         return s
 
 def same_types[T](cond: bool, t1: T, t2: T) -> T:
@@ -162,61 +147,41 @@ parameters simultaneously.
 def two_params[T](x: T, y: T) -> T:
     return x
 
-# TODO: no error
-# TODO: revealed: str
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(two_params("a", "b"))  # revealed: T
+reveal_type(two_params("a", "b"))  # revealed: Literal["a", "b"]
+reveal_type(two_params("a", 1))  # revealed: Literal["a", 1]
+```
 
-# TODO: no error
-# TODO: revealed: str | int
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(two_params("a", 1))  # revealed: T
+When one of the parameters is a union, we attempt to find the smallest specialization that satisfies
+all of the constraints.
+
+```py
+def union_param[T](x: T | None) -> T:
+    if x is None:
+        raise ValueError
+    return x
+
+reveal_type(union_param("a"))  # revealed: Literal["a"]
+reveal_type(union_param(1))  # revealed: Literal[1]
+reveal_type(union_param(None))  # revealed: Unknown
 ```
 
 ```py
-def param_with_union[T](x: T | int, y: T) -> T:
+def union_and_nonunion_params[T](x: T | int, y: T) -> T:
     return y
 
-# TODO: no error
-# TODO: revealed: str
-# error: [invalid-argument-type]
-reveal_type(param_with_union(1, "a"))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: str
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(param_with_union("a", "a"))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: int
-# error: [invalid-argument-type]
-reveal_type(param_with_union(1, 1))  # revealed: T
-
-# TODO: no error
-# TODO: revealed: str | int
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(param_with_union("a", 1))  # revealed: T
+reveal_type(union_and_nonunion_params(1, "a"))  # revealed: Literal["a"]
+reveal_type(union_and_nonunion_params("a", "a"))  # revealed: Literal["a"]
+reveal_type(union_and_nonunion_params(1, 1))  # revealed: Literal[1]
+reveal_type(union_and_nonunion_params(3, 1))  # revealed: Literal[1]
+reveal_type(union_and_nonunion_params("a", 1))  # revealed: Literal["a", 1]
 ```
 
 ```py
 def tuple_param[T, S](x: T | S, y: tuple[T, S]) -> tuple[T, S]:
     return y
 
-# TODO: no error
-# TODO: revealed: tuple[str, int]
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(tuple_param("a", ("a", 1)))  # revealed: tuple[T, S]
-
-# TODO: no error
-# TODO: revealed: tuple[str, int]
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(tuple_param(1, ("a", 1)))  # revealed: tuple[T, S]
+reveal_type(tuple_param("a", ("a", 1)))  # revealed: tuple[Literal["a"], Literal[1]]
+reveal_type(tuple_param(1, ("a", 1)))  # revealed: tuple[Literal["a"], Literal[1]]
 ```
 
 ## Inferring nested generic function calls
@@ -231,15 +196,6 @@ def f[T](x: T) -> tuple[T, int]:
 def g[T](x: T) -> T | None:
     return x
 
-# TODO: no error
-# TODO: revealed: tuple[str | None, int]
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(f(g("a")))  # revealed: tuple[T, int]
-
-# TODO: no error
-# TODO: revealed: tuple[str, int] | None
-# error: [invalid-argument-type]
-# error: [invalid-argument-type]
-reveal_type(g(f("a")))  # revealed: T | None
+reveal_type(f(g("a")))  # revealed: tuple[Literal["a"] | None, int]
+reveal_type(g(f("a")))  # revealed: tuple[Literal["a"], int] | None
 ```

crates/red_knot_python_semantic/resources/mdtest/generics/pep695.md

@@ -1,5 +1,10 @@
 # PEP 695 Generics
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 [PEP 695] and Python 3.12 introduced new, more ergonomic syntax for type variables.
 
 ## Type variables
@@ -59,19 +64,19 @@ is.)
 from knot_extensions import is_fully_static, static_assert
 from typing import Any
 
-def unbounded_unconstrained[T](t: list[T]) -> None:
+def unbounded_unconstrained[T](t: T) -> None:
     static_assert(is_fully_static(T))
 
-def bounded[T: int](t: list[T]) -> None:
+def bounded[T: int](t: T) -> None:
     static_assert(is_fully_static(T))
 
-def bounded_by_gradual[T: Any](t: list[T]) -> None:
+def bounded_by_gradual[T: Any](t: T) -> None:
     static_assert(not is_fully_static(T))
 
-def constrained[T: (int, str)](t: list[T]) -> None:
+def constrained[T: (int, str)](t: T) -> None:
     static_assert(is_fully_static(T))
 
-def constrained_by_gradual[T: (int, Any)](t: list[T]) -> None:
+def constrained_by_gradual[T: (int, Any)](t: T) -> None:
     static_assert(not is_fully_static(T))
 ```
 
@@ -94,7 +99,7 @@ class Base(Super): ...
 class Sub(Base): ...
 class Unrelated: ...
 
-def unbounded_unconstrained[T, U](t: list[T], u: list[U]) -> None:
+def unbounded_unconstrained[T, U](t: T, u: U) -> None:
     static_assert(is_assignable_to(T, T))
     static_assert(is_assignable_to(T, object))
     static_assert(not is_assignable_to(T, Super))
@@ -124,7 +129,7 @@ is a final class, since the typevar can still be specialized to `Never`.)
 from typing import Any
 from typing_extensions import final
 
-def bounded[T: Super](t: list[T]) -> None:
+def bounded[T: Super](t: T) -> None:
     static_assert(is_assignable_to(T, Super))
     static_assert(not is_assignable_to(T, Sub))
     static_assert(not is_assignable_to(Super, T))
@@ -135,7 +140,7 @@ def bounded[T: Super](t: list[T]) -> None:
     static_assert(not is_subtype_of(Super, T))
     static_assert(not is_subtype_of(Sub, T))
 
-def bounded_by_gradual[T: Any](t: list[T]) -> None:
+def bounded_by_gradual[T: Any](t: T) -> None:
     static_assert(is_assignable_to(T, Any))
     static_assert(is_assignable_to(Any, T))
     static_assert(is_assignable_to(T, Super))
@@ -153,7 +158,7 @@ def bounded_by_gradual[T: Any](t: list[T]) -> None:
 @final
 class FinalClass: ...
 
-def bounded_final[T: FinalClass](t: list[T]) -> None:
+def bounded_final[T: FinalClass](t: T) -> None:
     static_assert(is_assignable_to(T, FinalClass))
     static_assert(not is_assignable_to(FinalClass, T))
 
@@ -167,14 +172,14 @@ true even if both typevars are bounded by the same final class, since you can sp
 typevars to `Never` in addition to that final class.
 
 ```py
-def two_bounded[T: Super, U: Super](t: list[T], u: list[U]) -> None:
+def two_bounded[T: Super, U: Super](t: T, u: U) -> None:
     static_assert(not is_assignable_to(T, U))
     static_assert(not is_assignable_to(U, T))
 
     static_assert(not is_subtype_of(T, U))
     static_assert(not is_subtype_of(U, T))
 
-def two_final_bounded[T: FinalClass, U: FinalClass](t: list[T], u: list[U]) -> None:
+def two_final_bounded[T: FinalClass, U: FinalClass](t: T, u: U) -> None:
     static_assert(not is_assignable_to(T, U))
     static_assert(not is_assignable_to(U, T))
 
@@ -189,7 +194,7 @@ intersection of all of its constraints is a subtype of the typevar.
 ```py
 from knot_extensions import Intersection
 
-def constrained[T: (Base, Unrelated)](t: list[T]) -> None:
+def constrained[T: (Base, Unrelated)](t: T) -> None:
     static_assert(not is_assignable_to(T, Super))
     static_assert(not is_assignable_to(T, Base))
     static_assert(not is_assignable_to(T, Sub))
@@ -214,7 +219,7 @@ def constrained[T: (Base, Unrelated)](t: list[T]) -> None:
     static_assert(not is_subtype_of(Super | Unrelated, T))
     static_assert(is_subtype_of(Intersection[Base, Unrelated], T))
 
-def constrained_by_gradual[T: (Base, Any)](t: list[T]) -> None:
+def constrained_by_gradual[T: (Base, Any)](t: T) -> None:
     static_assert(is_assignable_to(T, Super))
     static_assert(is_assignable_to(T, Base))
     static_assert(not is_assignable_to(T, Sub))
@@ -256,7 +261,7 @@ distinct constraints, meaning that there is (still) no guarantee that they will
 the same type.
 
 ```py
-def two_constrained[T: (int, str), U: (int, str)](t: list[T], u: list[U]) -> None:
+def two_constrained[T: (int, str), U: (int, str)](t: T, u: U) -> None:
     static_assert(not is_assignable_to(T, U))
     static_assert(not is_assignable_to(U, T))
 
@@ -266,7 +271,7 @@ def two_constrained[T: (int, str), U: (int, str)](t: list[T], u: list[U]) -> Non
 @final
 class AnotherFinalClass: ...
 
-def two_final_constrained[T: (FinalClass, AnotherFinalClass), U: (FinalClass, AnotherFinalClass)](t: list[T], u: list[U]) -> None:
+def two_final_constrained[T: (FinalClass, AnotherFinalClass), U: (FinalClass, AnotherFinalClass)](t: T, u: U) -> None:
     static_assert(not is_assignable_to(T, U))
     static_assert(not is_assignable_to(U, T))
 
@@ -285,7 +290,7 @@ non-singleton type.
 ```py
 from knot_extensions import is_singleton, is_single_valued, static_assert
 
-def unbounded_unconstrained[T](t: list[T]) -> None:
+def unbounded_unconstrained[T](t: T) -> None:
     static_assert(not is_singleton(T))
     static_assert(not is_single_valued(T))
 ```
@@ -294,7 +299,7 @@ A bounded typevar is not a singleton, even if its bound is a singleton, since it
 specialized to `Never`.
 
 ```py
-def bounded[T: None](t: list[T]) -> None:
+def bounded[T: None](t: T) -> None:
     static_assert(not is_singleton(T))
     static_assert(not is_single_valued(T))
 ```
@@ -305,14 +310,14 @@ specialize a constrained typevar to a subtype of a constraint.)
 ```py
 from typing_extensions import Literal
 
-def constrained_non_singletons[T: (int, str)](t: list[T]) -> None:
+def constrained_non_singletons[T: (int, str)](t: T) -> None:
     static_assert(not is_singleton(T))
     static_assert(not is_single_valued(T))
 
-def constrained_singletons[T: (Literal[True], Literal[False])](t: list[T]) -> None:
+def constrained_singletons[T: (Literal[True], Literal[False])](t: T) -> None:
     static_assert(is_singleton(T))
 
-def constrained_single_valued[T: (Literal[True], tuple[()])](t: list[T]) -> None:
+def constrained_single_valued[T: (Literal[True], tuple[()])](t: T) -> None:
     static_assert(is_single_valued(T))
 ```
 
@@ -507,6 +512,20 @@ def remove_constraint[T: (int, str, bool)](t: T) -> None:
         reveal_type(x)  # revealed: T & Any
 ```
 
+The intersection of a typevar with any other type is assignable to (and if fully static, a subtype
+of) itself.
+
+```py
+from knot_extensions import is_assignable_to, is_subtype_of, static_assert, Not
+
+def intersection_is_assignable[T](t: T) -> None:
+    static_assert(is_assignable_to(Intersection[T, None], T))
+    static_assert(is_assignable_to(Intersection[T, Not[None]], T))
+
+    static_assert(is_subtype_of(Intersection[T, None], T))
+    static_assert(is_subtype_of(Intersection[T, Not[None]], T))
+```
+
 ## Narrowing
 
 We can use narrowing expressions to eliminate some of the possibilities of a constrained typevar:

crates/red_knot_python_semantic/resources/mdtest/generics/scoping.md

@@ -1,5 +1,10 @@
 # Scoping rules for type variables
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 Most of these tests come from the [Scoping rules for type variables][scoping] section of the typing
 spec.
 
@@ -59,14 +64,8 @@ to a different type each time.
 def f[T](x: T) -> T:
     return x
 
-# TODO: no error
-# TODO: revealed: int or Literal[1]
-# error: [invalid-argument-type]
-reveal_type(f(1))  # revealed: T
-# TODO: no error
-# TODO: revealed: str or Literal["a"]
-# error: [invalid-argument-type]
-reveal_type(f("a"))  # revealed: T
+reveal_type(f(1))  # revealed: Literal[1]
+reveal_type(f("a"))  # revealed: Literal["a"]
 ```
 
 ## Methods can mention class typevars
@@ -85,7 +84,7 @@ class C[T]:
 c: C[int] = C[int]()
 c.m1(1)
 c.m2(1)
-# error: [invalid-argument-type] "Object of type `Literal["string"]` cannot be assigned to parameter 2 (`x`) of bound method `m2`; expected type `int`"
+# error: [invalid-argument-type] "Argument to this function is incorrect: Expected `int`, found `Literal["string"]`"
 c.m2("string")
 ```
 
@@ -102,18 +101,18 @@ class C[T]:
     def f(self, x: T) -> str:
         return "a"
 
-reveal_type(getattr_static(C[int], "f"))  # revealed: Literal[f[int]]
+reveal_type(getattr_static(C[int], "f"))  # revealed: def f(self, x: int) -> str
 reveal_type(getattr_static(C[int], "f").__get__)  # revealed: <method-wrapper `__get__` of `f[int]`>
-reveal_type(getattr_static(C[int], "f").__get__(None, C[int]))  # revealed: Literal[f[int]]
-# revealed: <bound method `f` of `C[int]`>
+reveal_type(getattr_static(C[int], "f").__get__(None, C[int]))  # revealed: def f(self, x: int) -> str
+# revealed: bound method C[int].f(x: int) -> str
 reveal_type(getattr_static(C[int], "f").__get__(C[int](), C[int]))
 
-reveal_type(C[int].f)  # revealed: Literal[f[int]]
-reveal_type(C[int]().f)  # revealed: <bound method `f` of `C[int]`>
+reveal_type(C[int].f)  # revealed: def f(self, x: int) -> str
+reveal_type(C[int]().f)  # revealed: bound method C[int].f(x: int) -> str
 
 bound_method = C[int]().f
 reveal_type(bound_method.__self__)  # revealed: C[int]
-reveal_type(bound_method.__func__)  # revealed: Literal[f[int]]
+reveal_type(bound_method.__func__)  # revealed: def f(self, x: int) -> str
 
 reveal_type(C[int]().f(1))  # revealed: str
 reveal_type(bound_method(1))  # revealed: str
@@ -124,7 +123,7 @@ reveal_type(C[int].f(C[int](), 1))  # revealed: str
 class D[U](C[U]):
     pass
 
-reveal_type(D[int]().f)  # revealed: <bound method `f` of `D[int]`>
+reveal_type(D[int]().f)  # revealed: bound method D[int].f(x: int) -> str
 ```
 
 ## Methods can mention other typevars
@@ -138,8 +137,6 @@ from typing import TypeVar, Generic
 T = TypeVar("T")
 S = TypeVar("S")
 
-# TODO: no error
-# error: [invalid-base]
 class Legacy(Generic[T]):
     def m(self, x: T, y: S) -> S:
         return y
@@ -157,10 +154,7 @@ class C[T]:
         return y
 
 c: C[int] = C()
-# TODO: no errors
-# TODO: revealed: str
-# error: [invalid-argument-type]
-reveal_type(c.m(1, "string"))  # revealed: S
+reveal_type(c.m(1, "string"))  # revealed: Literal["string"]
 ```
 
 ## Unbound typevars
@@ -178,13 +172,11 @@ S = TypeVar("S")
 
 def f(x: T) -> None:
     x: list[T] = []
-    # TODO: error
+    # TODO: invalid-assignment error
     y: list[S] = []
 
-# TODO: no error
-# error: [invalid-base]
 class C(Generic[T]):
-    # TODO: error
+    # TODO: error: cannot use S if it's not in the current generic context
     x: list[S] = []
 
     # This is not an error, as shown in the previous test
@@ -204,11 +196,11 @@ S = TypeVar("S")
 
 def f[T](x: T) -> None:
     x: list[T] = []
-    # TODO: error
+    # TODO: invalid assignment error
     y: list[S] = []
 
 class C[T]:
-    # TODO: error
+    # TODO: error: cannot use S if it's not in the current generic context
     x: list[S] = []
 
     def m1(self, x: S) -> S:
@@ -263,8 +255,7 @@ def f[T](x: T, y: T) -> None:
     class Ok[S]: ...
     # TODO: error for reuse of typevar
     class Bad1[T]: ...
-    # TODO: no non-subscriptable error, error for reuse of typevar
-    # error: [non-subscriptable]
+    # TODO: error for reuse of typevar
     class Bad2(Iterable[T]): ...
 ```
 
@@ -277,8 +268,7 @@ class C[T]:
     class Ok1[S]: ...
     # TODO: error for reuse of typevar
     class Bad1[T]: ...
-    # TODO: no non-subscriptable error, error for reuse of typevar
-    # error: [non-subscriptable]
+    # TODO: error for reuse of typevar
     class Bad2(Iterable[T]): ...
 ```
 
@@ -292,7 +282,7 @@ class C[T]:
     ok1: list[T] = []
 
     class Bad:
-        # TODO: error
+        # TODO: error: cannot refer to T in nested scope
         bad: list[T] = []
 
     class Inner[S]: ...

crates/red_knot_python_semantic/resources/mdtest/generics/variance.md

@@ -0,0 +1,277 @@
+# Variance
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+Type variables have a property called _variance_ that affects the subtyping and assignability
+relations. Much more detail can be found in the [spec]. To summarize, each typevar is either
+**covariant**, **contravariant**, **invariant**, or **bivariant**. (Note that bivariance is not
+currently mentioned in the typing spec, but is a fourth case that we must consider.)
+
+For all of the examples below, we will consider a typevar `T`, a generic class using that typevar
+`C[T]`, and two types `A` and `B`.
+
+## Covariance
+
+With a covariant typevar, subtyping is in "alignment": if `A <: B`, then `C[A] <: C[B]`.
+
+Types that "produce" data on demand are covariant in their typevar. If you expect a sequence of
+`int`s, someone can safely provide a sequence of `bool`s, since each `bool` element that you would
+get from the sequence is a valid `int`.
+
+```py
+from knot_extensions import is_assignable_to, is_equivalent_to, is_gradual_equivalent_to, is_subtype_of, static_assert, Unknown
+from typing import Any
+
+class A: ...
+class B(A): ...
+
+class C[T]:
+    def receive(self) -> T:
+        raise ValueError
+
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_assignable_to(C[B], C[A]))
+static_assert(not is_assignable_to(C[A], C[B]))
+static_assert(is_assignable_to(C[A], C[Any]))
+static_assert(is_assignable_to(C[B], C[Any]))
+static_assert(is_assignable_to(C[Any], C[A]))
+static_assert(is_assignable_to(C[Any], C[B]))
+
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_subtype_of(C[B], C[A]))
+static_assert(not is_subtype_of(C[A], C[B]))
+static_assert(not is_subtype_of(C[A], C[Any]))
+static_assert(not is_subtype_of(C[B], C[Any]))
+static_assert(not is_subtype_of(C[Any], C[A]))
+static_assert(not is_subtype_of(C[Any], C[B]))
+
+static_assert(is_equivalent_to(C[A], C[A]))
+static_assert(is_equivalent_to(C[B], C[B]))
+static_assert(not is_equivalent_to(C[B], C[A]))
+static_assert(not is_equivalent_to(C[A], C[B]))
+static_assert(not is_equivalent_to(C[A], C[Any]))
+static_assert(not is_equivalent_to(C[B], C[Any]))
+static_assert(not is_equivalent_to(C[Any], C[A]))
+static_assert(not is_equivalent_to(C[Any], C[B]))
+
+static_assert(is_gradual_equivalent_to(C[A], C[A]))
+static_assert(is_gradual_equivalent_to(C[B], C[B]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Any]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Unknown]))
+static_assert(not is_gradual_equivalent_to(C[B], C[A]))
+static_assert(not is_gradual_equivalent_to(C[A], C[B]))
+static_assert(not is_gradual_equivalent_to(C[A], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[B], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[A]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[B]))
+```
+
+## Contravariance
+
+With a contravariant typevar, subtyping is in "opposition": if `A <: B`, then `C[B] <: C[A]`.
+
+Types that "consume" data are contravariant in their typevar. If you expect a consumer that receives
+`bool`s, someone can safely provide a consumer that expects to receive `int`s, since each `bool`
+that you pass into the consumer is a valid `int`.
+
+```py
+from knot_extensions import is_assignable_to, is_equivalent_to, is_gradual_equivalent_to, is_subtype_of, static_assert, Unknown
+from typing import Any
+
+class A: ...
+class B(A): ...
+
+class C[T]:
+    def send(self, value: T): ...
+
+static_assert(not is_assignable_to(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_assignable_to(C[A], C[B]))
+static_assert(is_assignable_to(C[A], C[Any]))
+static_assert(is_assignable_to(C[B], C[Any]))
+static_assert(is_assignable_to(C[Any], C[A]))
+static_assert(is_assignable_to(C[Any], C[B]))
+
+static_assert(not is_subtype_of(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_subtype_of(C[A], C[B]))
+static_assert(not is_subtype_of(C[A], C[Any]))
+static_assert(not is_subtype_of(C[B], C[Any]))
+static_assert(not is_subtype_of(C[Any], C[A]))
+static_assert(not is_subtype_of(C[Any], C[B]))
+
+static_assert(is_equivalent_to(C[A], C[A]))
+static_assert(is_equivalent_to(C[B], C[B]))
+static_assert(not is_equivalent_to(C[B], C[A]))
+static_assert(not is_equivalent_to(C[A], C[B]))
+static_assert(not is_equivalent_to(C[A], C[Any]))
+static_assert(not is_equivalent_to(C[B], C[Any]))
+static_assert(not is_equivalent_to(C[Any], C[A]))
+static_assert(not is_equivalent_to(C[Any], C[B]))
+
+static_assert(is_gradual_equivalent_to(C[A], C[A]))
+static_assert(is_gradual_equivalent_to(C[B], C[B]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Any]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Unknown]))
+static_assert(not is_gradual_equivalent_to(C[B], C[A]))
+static_assert(not is_gradual_equivalent_to(C[A], C[B]))
+static_assert(not is_gradual_equivalent_to(C[A], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[B], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[A]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[B]))
+```
+
+## Invariance
+
+With an invariant typevar, _no_ specializations of the generic class are subtypes of each other.
+
+This often occurs for types that are both producers _and_ consumers, like a mutable `list`.
+Iterating over the elements in a list would work with a covariant typevar, just like with the
+"producer" type above. Appending elements to a list would work with a contravariant typevar, just
+like with the "consumer" type above. However, a typevar cannot be both covariant and contravariant
+at the same time!
+
+If you expect a mutable list of `int`s, it's not safe for someone to provide you with a mutable list
+of `bool`s, since you might try to add an element to the list: if you try to add an `int`, the list
+would no longer only contain elements that are subtypes of `bool`.
+
+Conversely, if you expect a mutable list of `bool`s, it's not safe for someone to provide you with a
+mutable list of `int`s, since you might try to extract elements from the list: you expect every
+element that you extract to be a subtype of `bool`, but the list can contain any `int`.
+
+In the end, if you expect a mutable list, you must always be given a list of exactly that type,
+since we can't know in advance which of the allowed methods you'll want to use.
+
+```py
+from knot_extensions import is_assignable_to, is_equivalent_to, is_gradual_equivalent_to, is_subtype_of, static_assert, Unknown
+from typing import Any
+
+class A: ...
+class B(A): ...
+
+class C[T]:
+    def send(self, value: T): ...
+    def receive(self) -> T:
+        raise ValueError
+
+static_assert(not is_assignable_to(C[B], C[A]))
+static_assert(not is_assignable_to(C[A], C[B]))
+static_assert(is_assignable_to(C[A], C[Any]))
+static_assert(is_assignable_to(C[B], C[Any]))
+static_assert(is_assignable_to(C[Any], C[A]))
+static_assert(is_assignable_to(C[Any], C[B]))
+
+static_assert(not is_subtype_of(C[B], C[A]))
+static_assert(not is_subtype_of(C[A], C[B]))
+static_assert(not is_subtype_of(C[A], C[Any]))
+static_assert(not is_subtype_of(C[B], C[Any]))
+static_assert(not is_subtype_of(C[Any], C[A]))
+static_assert(not is_subtype_of(C[Any], C[B]))
+
+static_assert(is_equivalent_to(C[A], C[A]))
+static_assert(is_equivalent_to(C[B], C[B]))
+static_assert(not is_equivalent_to(C[B], C[A]))
+static_assert(not is_equivalent_to(C[A], C[B]))
+static_assert(not is_equivalent_to(C[A], C[Any]))
+static_assert(not is_equivalent_to(C[B], C[Any]))
+static_assert(not is_equivalent_to(C[Any], C[A]))
+static_assert(not is_equivalent_to(C[Any], C[B]))
+
+static_assert(is_gradual_equivalent_to(C[A], C[A]))
+static_assert(is_gradual_equivalent_to(C[B], C[B]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Any]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Unknown]))
+static_assert(not is_gradual_equivalent_to(C[B], C[A]))
+static_assert(not is_gradual_equivalent_to(C[A], C[B]))
+static_assert(not is_gradual_equivalent_to(C[A], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[B], C[Any]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[A]))
+static_assert(not is_gradual_equivalent_to(C[Any], C[B]))
+```
+
+## Bivariance
+
+With a bivariant typevar, _all_ specializations of the generic class are subtypes of (and in fact,
+equivalent to) each other.
+
+This is a bit of pathological case, which really only happens when the class doesn't use the typevar
+at all. (If it did, it would have to be covariant, contravariant, or invariant, depending on _how_
+the typevar was used.)
+
+```py
+from knot_extensions import is_assignable_to, is_equivalent_to, is_gradual_equivalent_to, is_subtype_of, static_assert, Unknown
+from typing import Any
+
+class A: ...
+class B(A): ...
+
+class C[T]:
+    pass
+
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_assignable_to(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_assignable_to(C[A], C[B]))
+static_assert(is_assignable_to(C[A], C[Any]))
+static_assert(is_assignable_to(C[B], C[Any]))
+static_assert(is_assignable_to(C[Any], C[A]))
+static_assert(is_assignable_to(C[Any], C[B]))
+
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_subtype_of(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_subtype_of(C[A], C[B]))
+static_assert(not is_subtype_of(C[A], C[Any]))
+static_assert(not is_subtype_of(C[B], C[Any]))
+static_assert(not is_subtype_of(C[Any], C[A]))
+static_assert(not is_subtype_of(C[Any], C[B]))
+
+static_assert(is_equivalent_to(C[A], C[A]))
+static_assert(is_equivalent_to(C[B], C[B]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_equivalent_to(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_equivalent_to(C[A], C[B]))
+static_assert(not is_equivalent_to(C[A], C[Any]))
+static_assert(not is_equivalent_to(C[B], C[Any]))
+static_assert(not is_equivalent_to(C[Any], C[A]))
+static_assert(not is_equivalent_to(C[Any], C[B]))
+
+static_assert(is_gradual_equivalent_to(C[A], C[A]))
+static_assert(is_gradual_equivalent_to(C[B], C[B]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Any]))
+static_assert(is_gradual_equivalent_to(C[Any], C[Unknown]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[B], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[A], C[B]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[A], C[Any]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[B], C[Any]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[Any], C[A]))
+# TODO: no error
+# error: [static-assert-error]
+static_assert(is_gradual_equivalent_to(C[Any], C[B]))
+```
+
+[spec]: https://typing.python.org/en/latest/spec/generics.html#variance

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

@@ -7,7 +7,7 @@ Builtin symbols can be explicitly imported:
 ```py
 import builtins
 
-reveal_type(builtins.chr)  # revealed: Literal[chr]
+reveal_type(builtins.chr)  # revealed: def chr(i: int | SupportsIndex, /) -> str
 ```
 
 ## Implicit use of builtin
@@ -15,7 +15,7 @@ reveal_type(builtins.chr)  # revealed: Literal[chr]
 Or used implicitly:
 
 ```py
-reveal_type(chr)  # revealed: Literal[chr]
+reveal_type(chr)  # revealed: def chr(i: int | SupportsIndex, /) -> str
 reveal_type(str)  # revealed: Literal[str]
 ```
 

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

@@ -103,8 +103,8 @@ else:
 ```py
 from b import f
 
-# TODO: We should disambiguate in such cases, showing `Literal[b.f, c.f]`.
-reveal_type(f)  # revealed: Literal[f, f]
+# TODO: We should disambiguate in such cases between `b.f` and `c.f`.
+reveal_type(f)  # revealed: (def f() -> Unknown) | (def f() -> Unknown)
 ```
 
 ## Reimport with stub declaration

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

@@ -122,6 +122,11 @@ from c import Y  # error: [unresolved-import]
 
 ## Esoteric definitions and redefinintions
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 We understand all public symbols defined in an external module as being imported by a `*` import,
 not just those that are defined in `StmtAssign` nodes and `StmtAnnAssign` nodes. This section
 provides tests for definitions, and redefinitions, that use more esoteric AST nodes.
@@ -626,6 +631,30 @@ reveal_type(X)  # revealed: Unknown
 reveal_type(Y)  # revealed: bool
 ```
 
+### An implicit import in a `.pyi` file later overridden by another assignment
+
+`a.pyi`:
+
+```pyi
+X: bool = True
+```
+
+`b.pyi`:
+
+```pyi
+from a import X
+
+X: bool = False
+```
+
+`c.py`:
+
+```py
+from b import *
+
+reveal_type(X)  # revealed: bool
+```
+
 ## Visibility constraints
 
 If an `importer` module contains a `from exporter import *` statement in its global namespace, the
@@ -865,15 +894,10 @@ from exporter import *
 
 reveal_type(X)  # revealed: bool
 
-# TODO none of these should error, should all reveal `bool`
-# error: [unresolved-reference]
-reveal_type(_private)  # revealed: Unknown
-# error: [unresolved-reference]
-reveal_type(__protected)  # revealed: Unknown
-# error: [unresolved-reference]
-reveal_type(__dunder__)  # revealed: Unknown
-# error: [unresolved-reference]
-reveal_type(___thunder___)  # revealed: Unknown
+reveal_type(_private)  # revealed: bool
+reveal_type(__protected)  # revealed: bool
+reveal_type(__dunder__)  # revealed: bool
+reveal_type(___thunder___)  # revealed: bool
 
 # TODO: should emit [unresolved-reference] diagnostic & reveal `Unknown`
 reveal_type(Y)  # revealed: bool
@@ -1034,8 +1058,8 @@ from exporter import *
 # At runtime, `f` is imported but `g` is not; to avoid false positives, however,
 # we treat `a` as though it does not have `__all__` at all,
 # which would imply that both symbols would be present.
-reveal_type(f)  # revealed: Literal[f]
-reveal_type(g)  # revealed: Literal[g]
+reveal_type(f)  # revealed: def f() -> str
+reveal_type(g)  # revealed: def g() -> int
 ```
 
 ### `__all__` conditionally defined in a statically known branch
@@ -1072,6 +1096,44 @@ reveal_type(Y)  # revealed: bool
 reveal_type(Z)  # revealed: Unknown
 ```
 
+### `__all__` conditionally defined in a statically known branch (2)
+
+The same example again, but with a different `python-version` set:
+
+```toml
+[environment]
+python-version = "3.10"
+```
+
+`exporter.py`:
+
+```py
+import sys
+
+X: bool = True
+
+if sys.version_info >= (3, 11):
+    __all__ = ["X", "Y"]
+    Y: bool = True
+else:
+    __all__ = ("Z",)
+    Z: bool = True
+```
+
+`importer.py`:
+
+```py
+from exporter import *
+
+# TODO: should reveal `Unknown` and emit `[unresolved-reference]`
+reveal_type(X)  # revealed: bool
+
+# error: [unresolved-reference]
+reveal_type(Y)  # revealed: Unknown
+
+reveal_type(Z)  # revealed: bool
+```
+
 ### `__all__` conditionally mutated in a statically known branch
 
 ```toml
@@ -1084,11 +1146,11 @@ python-version = "3.11"
 ```py
 import sys
 
-__all__ = ["X"]
+__all__ = []
 X: bool = True
 
 if sys.version_info >= (3, 11):
-    __all__.append("Y")
+    __all__.extend(["X", "Y"])
     Y: bool = True
 else:
     __all__.append("Z")
@@ -1107,6 +1169,45 @@ reveal_type(Y)  # revealed: bool
 reveal_type(Z)  # revealed: Unknown
 ```
 
+### `__all__` conditionally mutated in a statically known branch (2)
+
+The same example again, but with a different `python-version` set:
+
+```toml
+[environment]
+python-version = "3.10"
+```
+
+`exporter.py`:
+
+```py
+import sys
+
+__all__ = []
+X: bool = True
+
+if sys.version_info >= (3, 11):
+    __all__.extend(["X", "Y"])
+    Y: bool = True
+else:
+    __all__.append("Z")
+    Z: bool = True
+```
+
+`importer.py`:
+
+```py
+from exporter import *
+
+# TODO: should reveal `Unknown` & emit `[unresolved-reference]
+reveal_type(X)  # revealed: bool
+
+# error: [unresolved-reference]
+reveal_type(Y)  # revealed: Unknown
+
+reveal_type(Z)  # revealed: bool
+```
+
 ### Empty `__all__`
 
 An empty `__all__` is valid, but a `*` import from a module with an empty `__all__` results in 0
@@ -1166,6 +1267,7 @@ from b import *
 
 # TODO: should not error, should reveal `bool`
 # (`X` is re-exported from `b.pyi` due to presence in `__all__`)
+# See https://github.com/astral-sh/ruff/issues/16159
 #
 # error: [unresolved-reference]
 reveal_type(X)  # revealed: Unknown
@@ -1198,7 +1300,7 @@ f()
 ```py
 from a import *
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f() -> Unknown
 
 # TODO: we're undecided about whether we should consider this a false positive or not.
 # Mutating the global scope to add a symbol from an inner scope will not *necessarily* result

crates/red_knot_python_semantic/resources/mdtest/intersection_types.md

@@ -842,7 +842,7 @@ def unknown(
 
 ### Mixed dynamic types
 
-We currently do not simplify mixed dynamic types, but might consider doing so in the future:
+Gradually-equivalent types can be simplified out of intersections:
 
 ```py
 from typing import Any
@@ -854,10 +854,10 @@ def mixed(
     i3: Intersection[Not[Any], Unknown],
     i4: Intersection[Not[Any], Not[Unknown]],
 ) -> None:
-    reveal_type(i1)  # revealed: Any & Unknown
-    reveal_type(i2)  # revealed: Any & Unknown
-    reveal_type(i3)  # revealed: Any & Unknown
-    reveal_type(i4)  # revealed: Any & Unknown
+    reveal_type(i1)  # revealed: Any
+    reveal_type(i2)  # revealed: Any
+    reveal_type(i3)  # revealed: Any
+    reveal_type(i4)  # revealed: Any
 ```
 
 ## Invalid

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

@@ -321,7 +321,7 @@ def _(flag: bool):
         # TODO... `int` might be ideal here?
         reveal_type(x)  # revealed: int | Unknown
 
-    # error: [not-iterable] "Object of type `Iterable2` may not be iterable because its `__iter__` attribute (with type `<bound method `__iter__` of `Iterable2`> | None`) may not be callable"
+    # error: [not-iterable] "Object of type `Iterable2` may not be iterable because its `__iter__` attribute (with type `(bound method Iterable2.__iter__() -> Iterator) | None`) may not be callable"
     for y in Iterable2():
         # TODO... `int` might be ideal here?
         reveal_type(y)  # revealed: int | Unknown

crates/red_knot_python_semantic/resources/mdtest/metaclass.md

@@ -216,6 +216,11 @@ reveal_type(A.__class__)  # revealed: type[Unknown]
 
 ## PEP 695 generic
 
+```toml
+[environment]
+python-version = "3.12"
+```
+
 ```py
 class M(type): ...
 class A[T: str](metaclass=M): ...

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

@@ -0,0 +1,53 @@
+# Narrowing with assert statements
+
+## `assert` a value `is None` or `is not None`
+
+```py
+def _(x: str | None, y: str | None):
+    assert x is not None
+    reveal_type(x)  # revealed: str
+    assert y is None
+    reveal_type(y)  # revealed: None
+```
+
+## `assert` a value is truthy or falsy
+
+```py
+def _(x: bool, y: bool):
+    assert x
+    reveal_type(x)  # revealed: Literal[True]
+    assert not y
+    reveal_type(y)  # revealed: Literal[False]
+```
+
+## `assert` with `is` and `==` for literals
+
+```py
+from typing import Literal
+
+def _(x: Literal[1, 2, 3], y: Literal[1, 2, 3]):
+    assert x is 2
+    reveal_type(x)  # revealed: Literal[2]
+    assert y == 2
+    reveal_type(y)  # revealed: Literal[1, 2, 3]
+```
+
+## `assert` with `isinstance`
+
+```py
+def _(x: int | str):
+    assert isinstance(x, int)
+    reveal_type(x)  # revealed: int
+```
+
+## `assert` a value `in` a tuple
+
+```py
+from typing import Literal
+
+def _(x: Literal[1, 2, 3], y: Literal[1, 2, 3]):
+    assert x in (1, 2)
+    reveal_type(x)  # revealed: Literal[1, 2]
+    assert y not in (1, 2)
+    reveal_type(y)  # revealed: Literal[3]
+```

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

@@ -223,3 +223,15 @@ def _(x: str | None, y: str | None):
     if y is not x:
         reveal_type(y)  # revealed: str | None
 ```
+
+## Assignment expressions
+
+```py
+def f() -> bool:
+    return True
+
+if x := f():
+    reveal_type(x)  # revealed: Literal[True]
+else:
+    reveal_type(x)  # revealed: Literal[False]
+```

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

@@ -47,3 +47,16 @@ def _(flag1: bool, flag2: bool):
         # TODO should be Never
         reveal_type(x)  # revealed: Literal[1, 2]
 ```
+
+## Assignment expressions
+
+```py
+def f() -> int | str | None: ...
+
+if isinstance(x := f(), int):
+    reveal_type(x)  # revealed: int
+elif isinstance(x, str):
+    reveal_type(x)  # revealed: str & ~int
+else:
+    reveal_type(x)  # revealed: None
+```

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

@@ -78,3 +78,17 @@ def _(x: Literal[1, "a", "b", "c", "d"]):
     else:
         reveal_type(x)  # revealed: Literal[1, "d"]
 ```
+
+## Assignment expressions
+
+```py
+from typing import Literal
+
+def f() -> Literal[1, 2, 3]:
+    return 1
+
+if (x := f()) in (1,):
+    reveal_type(x)  # revealed: Literal[1]
+else:
+    reveal_type(x)  # revealed: Literal[2, 3]
+```

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

@@ -100,3 +100,16 @@ def _(flag: bool):
     else:
         reveal_type(x)  # revealed: Literal[42]
 ```
+
+## Assignment expressions
+
+```py
+from typing import Literal
+
+def f() -> Literal[1, 2] | None: ...
+
+if (x := f()) is None:
+    reveal_type(x)  # revealed: None
+else:
+    reveal_type(x)  # revealed: Literal[1, 2]
+```

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

@@ -82,3 +82,14 @@ def _(x_flag: bool, y_flag: bool):
         reveal_type(x)  # revealed: bool
         reveal_type(y)  # revealed: bool
 ```
+
+## Assignment expressions
+
+```py
+def f() -> int | str | None: ...
+
+if (x := f()) is not None:
+    reveal_type(x)  # revealed: int | str
+else:
+    reveal_type(x)  # revealed: None
+```

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

@@ -89,3 +89,18 @@ def _(flag1: bool, flag2: bool, a: int):
     else:
         reveal_type(x)  # revealed: Literal[1, 2]
 ```
+
+## Assignment expressions
+
+```py
+from typing import Literal
+
+def f() -> Literal[1, 2, 3]:
+    return 1
+
+if (x := f()) != 1:
+    reveal_type(x)  # revealed: Literal[2, 3]
+else:
+    # TODO should be Literal[1]
+    reveal_type(x)  # revealed: Literal[1, 2, 3]
+```

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

@@ -1,5 +1,10 @@
 # Narrowing for `match` statements
 
+```toml
+[environment]
+python-version = "3.10"
+```
+
 ## Single `match` pattern
 
 ```py
@@ -34,8 +39,7 @@ match x:
     case A():
         reveal_type(x)  # revealed: A
     case B():
-        # TODO could be `B & ~A`
-        reveal_type(x)  # revealed: B
+        reveal_type(x)  # revealed: B & ~A
 
 reveal_type(x)  # revealed: object
 ```
@@ -83,7 +87,7 @@ match x:
     case 6.0:
         reveal_type(x)  # revealed: float
     case 1j:
-        reveal_type(x)  # revealed: complex
+        reveal_type(x)  # revealed: complex & ~float
     case b"foo":
         reveal_type(x)  # revealed: Literal[b"foo"]
 
@@ -129,11 +133,11 @@ match x:
     case "foo" | 42 | None:
         reveal_type(x)  # revealed: Literal["foo", 42] | None
     case "foo" | tuple():
-        reveal_type(x)  # revealed: Literal["foo"] | tuple
+        reveal_type(x)  # revealed: tuple
     case True | False:
         reveal_type(x)  # revealed: bool
     case 3.14 | 2.718 | 1.414:
-        reveal_type(x)  # revealed: float
+        reveal_type(x)  # revealed: float & ~tuple
 
 reveal_type(x)  # revealed: object
 ```
@@ -160,3 +164,49 @@ match x:
 
 reveal_type(x)  # revealed: object
 ```
+
+## Narrowing due to guard
+
+```py
+def get_object() -> object:
+    return object()
+
+x = get_object()
+
+reveal_type(x)  # revealed: object
+
+match x:
+    case str() | float() if type(x) is str:
+        reveal_type(x)  #  revealed: str
+    case "foo" | 42 | None if isinstance(x, int):
+        reveal_type(x)  #  revealed: Literal[42]
+    case False if x:
+        reveal_type(x)  #  revealed: Never
+    case "foo" if x := "bar":
+        reveal_type(x)  # revealed: Literal["bar"]
+
+reveal_type(x)  # revealed: object
+```
+
+## Guard and reveal_type in guard
+
+```py
+def get_object() -> object:
+    return object()
+
+x = get_object()
+
+reveal_type(x)  # revealed: object
+
+match x:
+    case str() | float() if type(x) is str and reveal_type(x):  # revealed: str
+        pass
+    case "foo" | 42 | None if isinstance(x, int) and reveal_type(x):  #  revealed: Literal[42]
+        pass
+    case False if x and reveal_type(x):  #  revealed: Never
+        pass
+    case "foo" if (x := "bar") and reveal_type(x):  #  revealed: Literal["bar"]
+        pass
+
+reveal_type(x)  # revealed: object
+```

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

@@ -63,7 +63,7 @@ def bar(world: str, *args, **kwargs) -> float:
 x = foo if flag() else bar
 
 if x:
-    reveal_type(x)  # revealed: Literal[foo, bar]
+    reveal_type(x)  # revealed: (def foo(hello: int) -> bytes) | (def bar(world: str, *args, **kwargs) -> int | float)
 else:
     reveal_type(x)  # revealed: Never
 ```
@@ -246,7 +246,7 @@ class MetaTruthy(type):
 
 class MetaDeferred(type):
     def __bool__(self) -> MetaAmbiguous:
-        return MetaAmbiguous()
+        raise NotImplementedError
 
 class AmbiguousClass(metaclass=MetaAmbiguous): ...
 class FalsyClass(metaclass=MetaFalsy): ...

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

@@ -111,6 +111,11 @@ def _(x: A | B):
 
 ## Narrowing for generic classes
 
+```toml
+[environment]
+python-version = "3.13"
+```
+
 Note that `type` returns the runtime class of an object, which does _not_ include specializations in
 the case of a generic class. (The typevars are erased.) That means we cannot narrow the type to the
 specialization that we compare with; we must narrow to an unknown specialization of the generic
@@ -139,3 +144,13 @@ def _(x: Base):
         # express a constraint like `Base & ~ProperSubtypeOf[Base]`.
         reveal_type(x)  # revealed: Base
 ```
+
+## Assignment expressions
+
+```py
+def _(x: object):
+    if (y := type(x)) is bool:
+        reveal_type(y)  # revealed: Literal[bool]
+    if (type(y := x)) is bool:
+        reveal_type(y)  # revealed: bool
+```

crates/red_knot_python_semantic/resources/mdtest/overloads.md

@@ -0,0 +1,638 @@
+# Overloads
+
+Reference: <https://typing.python.org/en/latest/spec/overload.html>
+
+## `typing.overload`
+
+The definition of `typing.overload` in typeshed is an identity function.
+
+```py
+from typing import overload
+
+def foo(x: int) -> int:
+    return x
+
+reveal_type(foo)  # revealed: def foo(x: int) -> int
+bar = overload(foo)
+reveal_type(bar)  # revealed: def foo(x: int) -> int
+```
+
+## Functions
+
+```py
+from typing import overload
+
+@overload
+def add() -> None: ...
+@overload
+def add(x: int) -> int: ...
+@overload
+def add(x: int, y: int) -> int: ...
+def add(x: int | None = None, y: int | None = None) -> int | None:
+    return (x or 0) + (y or 0)
+
+reveal_type(add)  # revealed: Overload[() -> None, (x: int) -> int, (x: int, y: int) -> int]
+reveal_type(add())  # revealed: None
+reveal_type(add(1))  # revealed: int
+reveal_type(add(1, 2))  # revealed: int
+```
+
+## Overriding
+
+These scenarios are to verify that the overloaded and non-overloaded definitions are correctly
+overridden by each other.
+
+An overloaded function is overriding another overloaded function:
+
+```py
+from typing import overload
+
+@overload
+def foo() -> None: ...
+@overload
+def foo(x: int) -> int: ...
+def foo(x: int | None = None) -> int | None:
+    return x
+
+reveal_type(foo)  # revealed: Overload[() -> None, (x: int) -> int]
+reveal_type(foo())  # revealed: None
+reveal_type(foo(1))  # revealed: int
+
+@overload
+def foo() -> None: ...
+@overload
+def foo(x: str) -> str: ...
+def foo(x: str | None = None) -> str | None:
+    return x
+
+reveal_type(foo)  # revealed: Overload[() -> None, (x: str) -> str]
+reveal_type(foo())  # revealed: None
+reveal_type(foo(""))  # revealed: str
+```
+
+A non-overloaded function is overriding an overloaded function:
+
+```py
+def foo(x: int) -> int:
+    return x
+
+reveal_type(foo)  # revealed: def foo(x: int) -> int
+```
+
+An overloaded function is overriding a non-overloaded function:
+
+```py
+reveal_type(foo)  # revealed: def foo(x: int) -> int
+
+@overload
+def foo() -> None: ...
+@overload
+def foo(x: bytes) -> bytes: ...
+def foo(x: bytes | None = None) -> bytes | None:
+    return x
+
+reveal_type(foo)  # revealed: Overload[() -> None, (x: bytes) -> bytes]
+reveal_type(foo())  # revealed: None
+reveal_type(foo(b""))  # revealed: bytes
+```
+
+## Methods
+
+```py
+from typing import overload
+
+class Foo1:
+    @overload
+    def method(self) -> None: ...
+    @overload
+    def method(self, x: int) -> int: ...
+    def method(self, x: int | None = None) -> int | None:
+        return x
+
+foo1 = Foo1()
+reveal_type(foo1.method)  # revealed: Overload[() -> None, (x: int) -> int]
+reveal_type(foo1.method())  # revealed: None
+reveal_type(foo1.method(1))  # revealed: int
+
+class Foo2:
+    @overload
+    def method(self) -> None: ...
+    @overload
+    def method(self, x: str) -> str: ...
+    def method(self, x: str | None = None) -> str | None:
+        return x
+
+foo2 = Foo2()
+reveal_type(foo2.method)  # revealed: Overload[() -> None, (x: str) -> str]
+reveal_type(foo2.method())  # revealed: None
+reveal_type(foo2.method(""))  # revealed: str
+```
+
+## Constructor
+
+```py
+from typing import overload
+
+class Foo:
+    @overload
+    def __init__(self) -> None: ...
+    @overload
+    def __init__(self, x: int) -> None: ...
+    def __init__(self, x: int | None = None) -> None:
+        self.x = x
+
+foo = Foo()
+reveal_type(foo)  # revealed: Foo
+reveal_type(foo.x)  # revealed: Unknown | int | None
+
+foo1 = Foo(1)
+reveal_type(foo1)  # revealed: Foo
+reveal_type(foo1.x)  # revealed: Unknown | int | None
+```
+
+## Version specific
+
+Function definitions can vary between multiple Python versions.
+
+### Overload and non-overload (3.9)
+
+Here, the same function is overloaded in one version and not in another.
+
+```toml
+[environment]
+python-version = "3.9"
+```
+
+```py
+import sys
+from typing import overload
+
+if sys.version_info < (3, 10):
+    def func(x: int) -> int:
+        return x
+
+elif sys.version_info <= (3, 12):
+    @overload
+    def func() -> None: ...
+    @overload
+    def func(x: int) -> int: ...
+    def func(x: int | None = None) -> int | None:
+        return x
+
+reveal_type(func)  # revealed: def func(x: int) -> int
+func()  # error: [missing-argument]
+```
+
+### Overload and non-overload (3.10)
+
+```toml
+[environment]
+python-version = "3.10"
+```
+
+```py
+import sys
+from typing import overload
+
+if sys.version_info < (3, 10):
+    def func(x: int) -> int:
+        return x
+
+elif sys.version_info <= (3, 12):
+    @overload
+    def func() -> None: ...
+    @overload
+    def func(x: int) -> int: ...
+    def func(x: int | None = None) -> int | None:
+        return x
+
+reveal_type(func)  # revealed: Overload[() -> None, (x: int) -> int]
+reveal_type(func())  # revealed: None
+reveal_type(func(1))  # revealed: int
+```
+
+### Some overloads are version specific (3.9)
+
+```toml
+[environment]
+python-version = "3.9"
+```
+
+`overloaded.pyi`:
+
+```pyi
+import sys
+from typing import overload
+
+if sys.version_info >= (3, 10):
+    @overload
+    def func() -> None: ...
+
+@overload
+def func(x: int) -> int: ...
+@overload
+def func(x: str) -> str: ...
+```
+
+`main.py`:
+
+```py
+from overloaded import func
+
+reveal_type(func)  # revealed: Overload[(x: int) -> int, (x: str) -> str]
+func()  # error: [no-matching-overload]
+reveal_type(func(1))  # revealed: int
+reveal_type(func(""))  # revealed: str
+```
+
+### Some overloads are version specific (3.10)
+
+```toml
+[environment]
+python-version = "3.10"
+```
+
+`overloaded.pyi`:
+
+```pyi
+import sys
+from typing import overload
+
+@overload
+def func() -> None: ...
+
+if sys.version_info >= (3, 10):
+    @overload
+    def func(x: int) -> int: ...
+
+@overload
+def func(x: str) -> str: ...
+```
+
+`main.py`:
+
+```py
+from overloaded import func
+
+reveal_type(func)  # revealed: Overload[() -> None, (x: int) -> int, (x: str) -> str]
+reveal_type(func())  # revealed: None
+reveal_type(func(1))  # revealed: int
+reveal_type(func(""))  # revealed: str
+```
+
+## Generic
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+For an overloaded generic function, it's not necessary for all overloads to be generic.
+
+```py
+from typing import overload
+
+@overload
+def func() -> None: ...
+@overload
+def func[T](x: T) -> T: ...
+def func[T](x: T | None = None) -> T | None:
+    return x
+
+reveal_type(func)  # revealed: Overload[() -> None, (x: T) -> T]
+reveal_type(func())  # revealed: None
+reveal_type(func(1))  # revealed: Literal[1]
+reveal_type(func(""))  # revealed: Literal[""]
+```
+
+## Invalid
+
+### At least two overloads
+
+At least two `@overload`-decorated definitions must be present.
+
+```py
+from typing import overload
+
+# TODO: error
+@overload
+def func(x: int) -> int: ...
+def func(x: int | str) -> int | str:
+    return x
+```
+
+### Overload without an implementation
+
+#### Regular modules
+
+In regular modules, a series of `@overload`-decorated definitions must be followed by exactly one
+non-`@overload`-decorated definition (for the same function/method).
+
+```py
+from typing import overload
+
+# TODO: error because implementation does not exists
+@overload
+def func(x: int) -> int: ...
+@overload
+def func(x: str) -> str: ...
+
+class Foo:
+    # TODO: error because implementation does not exists
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+```
+
+#### Stub files
+
+Overload definitions within stub files are exempt from this check.
+
+```pyi
+from typing import overload
+
+@overload
+def func(x: int) -> int: ...
+@overload
+def func(x: str) -> str: ...
+```
+
+#### Protocols
+
+Overload definitions within protocols are exempt from this check.
+
+```py
+from typing import Protocol, overload
+
+class Foo(Protocol):
+    @overload
+    def f(self, x: int) -> int: ...
+    @overload
+    def f(self, x: str) -> str: ...
+```
+
+#### Abstract methods
+
+Overload definitions within abstract base classes are exempt from this check.
+
+```py
+from abc import ABC, abstractmethod
+from typing import overload
+
+class AbstractFoo(ABC):
+    @overload
+    @abstractmethod
+    def f(self, x: int) -> int: ...
+    @overload
+    @abstractmethod
+    def f(self, x: str) -> str: ...
+```
+
+Using the `@abstractmethod` decorator requires that the class's metaclass is `ABCMeta` or is derived
+from it.
+
+```py
+class Foo:
+    # TODO: Error because implementation does not exists
+    @overload
+    @abstractmethod
+    def f(self, x: int) -> int: ...
+    @overload
+    @abstractmethod
+    def f(self, x: str) -> str: ...
+```
+
+And, the `@abstractmethod` decorator must be present on all the `@overload`-ed methods.
+
+```py
+class PartialFoo1(ABC):
+    @overload
+    @abstractmethod
+    def f(self, x: int) -> int: ...
+    @overload
+    def f(self, x: str) -> str: ...
+
+class PartialFoo(ABC):
+    @overload
+    def f(self, x: int) -> int: ...
+    @overload
+    @abstractmethod
+    def f(self, x: str) -> str: ...
+```
+
+### Inconsistent decorators
+
+#### `@staticmethod` / `@classmethod`
+
+If one overload signature is decorated with `@staticmethod` or `@classmethod`, all overload
+signatures must be similarly decorated. The implementation, if present, must also have a consistent
+decorator.
+
+```py
+from __future__ import annotations
+
+from typing import overload
+
+class CheckStaticMethod:
+    # TODO: error because `@staticmethod` does not exist on all overloads
+    @overload
+    def method1(x: int) -> int: ...
+    @overload
+    def method1(x: str) -> str: ...
+    @staticmethod
+    def method1(x: int | str) -> int | str:
+        return x
+    # TODO: error because `@staticmethod` does not exist on all overloads
+    @overload
+    def method2(x: int) -> int: ...
+    @overload
+    @staticmethod
+    def method2(x: str) -> str: ...
+    @staticmethod
+    def method2(x: int | str) -> int | str:
+        return x
+    # TODO: error because `@staticmethod` does not exist on the implementation
+    @overload
+    @staticmethod
+    def method3(x: int) -> int: ...
+    @overload
+    @staticmethod
+    def method3(x: str) -> str: ...
+    def method3(x: int | str) -> int | str:
+        return x
+
+    @overload
+    @staticmethod
+    def method4(x: int) -> int: ...
+    @overload
+    @staticmethod
+    def method4(x: str) -> str: ...
+    @staticmethod
+    def method4(x: int | str) -> int | str:
+        return x
+
+class CheckClassMethod:
+    def __init__(self, x: int) -> None:
+        self.x = x
+    # TODO: error because `@classmethod` does not exist on all overloads
+    @overload
+    @classmethod
+    def try_from1(cls, x: int) -> CheckClassMethod: ...
+    @overload
+    def try_from1(cls, x: str) -> None: ...
+    @classmethod
+    def try_from1(cls, x: int | str) -> CheckClassMethod | None:
+        if isinstance(x, int):
+            return cls(x)
+        return None
+    # TODO: error because `@classmethod` does not exist on all overloads
+    @overload
+    def try_from2(cls, x: int) -> CheckClassMethod: ...
+    @overload
+    @classmethod
+    def try_from2(cls, x: str) -> None: ...
+    @classmethod
+    def try_from2(cls, x: int | str) -> CheckClassMethod | None:
+        if isinstance(x, int):
+            return cls(x)
+        return None
+    # TODO: error because `@classmethod` does not exist on the implementation
+    @overload
+    @classmethod
+    def try_from3(cls, x: int) -> CheckClassMethod: ...
+    @overload
+    @classmethod
+    def try_from3(cls, x: str) -> None: ...
+    def try_from3(cls, x: int | str) -> CheckClassMethod | None:
+        if isinstance(x, int):
+            return cls(x)
+        return None
+
+    @overload
+    @classmethod
+    def try_from4(cls, x: int) -> CheckClassMethod: ...
+    @overload
+    @classmethod
+    def try_from4(cls, x: str) -> None: ...
+    @classmethod
+    def try_from4(cls, x: int | str) -> CheckClassMethod | None:
+        if isinstance(x, int):
+            return cls(x)
+        return None
+```
+
+#### `@final` / `@override`
+
+If a `@final` or `@override` decorator is supplied for a function with overloads, the decorator
+should be applied only to the overload implementation if it is present.
+
+```py
+from typing_extensions import final, overload, override
+
+class Foo:
+    @overload
+    def method1(self, x: int) -> int: ...
+    @overload
+    def method1(self, x: str) -> str: ...
+    @final
+    def method1(self, x: int | str) -> int | str:
+        return x
+    # TODO: error because `@final` is not on the implementation
+    @overload
+    @final
+    def method2(self, x: int) -> int: ...
+    @overload
+    def method2(self, x: str) -> str: ...
+    def method2(self, x: int | str) -> int | str:
+        return x
+    # TODO: error because `@final` is not on the implementation
+    @overload
+    def method3(self, x: int) -> int: ...
+    @overload
+    @final
+    def method3(self, x: str) -> str: ...
+    def method3(self, x: int | str) -> int | str:
+        return x
+
+class Base:
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+    def method(self, x: int | str) -> int | str:
+        return x
+
+class Sub1(Base):
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+    @override
+    def method(self, x: int | str) -> int | str:
+        return x
+
+class Sub2(Base):
+    # TODO: error because `@override` is not on the implementation
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    @override
+    def method(self, x: str) -> str: ...
+    def method(self, x: int | str) -> int | str:
+        return x
+
+class Sub3(Base):
+    # TODO: error because `@override` is not on the implementation
+    @overload
+    @override
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+    def method(self, x: int | str) -> int | str:
+        return x
+```
+
+#### `@final` / `@override` in stub files
+
+If an overload implementation isn’t present (for example, in a stub file), the `@final` or
+`@override` decorator should be applied only to the first overload.
+
+```pyi
+from typing_extensions import final, overload, override
+
+class Foo:
+    @overload
+    @final
+    def method1(self, x: int) -> int: ...
+    @overload
+    def method1(self, x: str) -> str: ...
+
+    # TODO: error because `@final` is not on the first overload
+    @overload
+    def method2(self, x: int) -> int: ...
+    @final
+    @overload
+    def method2(self, x: str) -> str: ...
+
+class Base:
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+
+class Sub1(Base):
+    @overload
+    @override
+    def method(self, x: int) -> int: ...
+    @overload
+    def method(self, x: str) -> str: ...
+
+class Sub2(Base):
+    # TODO: error because `@override` is not on the first overload
+    @overload
+    def method(self, x: int) -> int: ...
+    @overload
+    @override
+    def method(self, x: str) -> str: ...
+```

crates/red_knot_python_semantic/resources/mdtest/properties.md

@@ -146,7 +146,7 @@ class C:
     @property
     def attr(self) -> int:
         return 1
-    # error: [invalid-argument-type] "Object of type `Literal[attr]` cannot be assigned to parameter 2 (`fset`) of bound method `setter`; expected type `(Any, Any, /) -> None`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `(Any, Any, /) -> None`, found `def attr(self) -> None`"
     @attr.setter
     def attr(self) -> None:
         pass
@@ -156,7 +156,7 @@ class C:
 
 ```py
 class C:
-    # error: [invalid-argument-type] "Object of type `Literal[attr]` cannot be assigned to parameter 1 (`fget`) of class `property`; expected type `((Any, /) -> Any) | None`"
+    # error: [invalid-argument-type] "Argument to this function is incorrect: Expected `((Any, /) -> Any) | None`, found `def attr(self, x: int) -> int`"
     @property
     def attr(self, x: int) -> int:
         return 1
@@ -294,10 +294,10 @@ Properties also have `fget` and `fset` attributes that can be used to retrieve t
 and setter functions, respectively.
 
 ```py
-reveal_type(attr_property.fget)  # revealed: Literal[attr]
+reveal_type(attr_property.fget)  # revealed: def attr(self) -> int
 reveal_type(attr_property.fget(c))  # revealed: int
 
-reveal_type(attr_property.fset)  # revealed: Literal[attr]
+reveal_type(attr_property.fset)  # revealed: def attr(self, value: str) -> None
 reveal_type(attr_property.fset(c, "a"))  # revealed: None
 
 # error: [invalid-argument-type]

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

@@ -13,7 +13,7 @@ if returns_bool():
     chr: int = 1
 
 def f():
-    reveal_type(chr)  # revealed: int | Literal[chr]
+    reveal_type(chr)  # revealed: int | (def chr(i: int | SupportsIndex, /) -> str)
 ```
 
 ## Conditionally global or builtin, with annotation
@@ -28,5 +28,5 @@ if returns_bool():
     chr: int = 1
 
 def f():
-    reveal_type(chr)  # revealed: int | Literal[chr]
+    reveal_type(chr)  # revealed: int | (def chr(i: int | SupportsIndex, /) -> str)
 ```

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

@@ -14,7 +14,7 @@ reveal_type(__package__)  # revealed: str | None
 reveal_type(__doc__)  # revealed: str | None
 reveal_type(__spec__)  # revealed: ModuleSpec | None
 
-reveal_type(__path__)  # revealed: @Todo(generics)
+reveal_type(__path__)  # revealed: @Todo(specialized non-generic class)
 
 class X:
     reveal_type(__name__)  # revealed: str
@@ -51,15 +51,15 @@ inside the module:
 import typing
 
 reveal_type(typing.__name__)  # revealed: str
-reveal_type(typing.__init__)  # revealed: <bound method `__init__` of `ModuleType`>
+reveal_type(typing.__init__)  # revealed: bound method ModuleType.__init__(name: str, doc: str | None = ellipsis) -> None
 
 # These come from `builtins.object`, not `types.ModuleType`:
-reveal_type(typing.__eq__)  # revealed: <bound method `__eq__` of `ModuleType`>
+reveal_type(typing.__eq__)  # revealed: bound method ModuleType.__eq__(value: object, /) -> bool
 
 reveal_type(typing.__class__)  # revealed: Literal[ModuleType]
 
 # TODO: needs support generics; should be `dict[str, Any]`:
-reveal_type(typing.__dict__)  # revealed: @Todo(generics)
+reveal_type(typing.__dict__)  # revealed: @Todo(specialized non-generic class)
 ```
 
 Typeshed includes a fake `__getattr__` method in the stub for `types.ModuleType` to help out with
@@ -92,8 +92,8 @@ import foo
 from foo import __dict__ as foo_dict
 
 # TODO: needs support generics; should be `dict[str, Any]` for both of these:
-reveal_type(foo.__dict__)  # revealed: @Todo(generics)
-reveal_type(foo_dict)  # revealed: @Todo(generics)
+reveal_type(foo.__dict__)  # revealed: @Todo(specialized non-generic class)
+reveal_type(foo_dict)  # revealed: @Todo(specialized non-generic class)
 ```
 
 ## Conditionally global or `ModuleType` attribute

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

@@ -37,17 +37,17 @@ reveal_type(f)  # revealed: Literal[1]
 
 def f(): ...
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f() -> Unknown
 
 def f(x: int) -> int:
     raise NotImplementedError
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f(x: int) -> int
 
 f: int = 1
 reveal_type(f)  # revealed: Literal[1]
 
 def f(): ...
 
-reveal_type(f)  # revealed: Literal[f]
+reveal_type(f)  # revealed: def f() -> Unknown
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Bad_`__getitem__`_method.snap

@@ -40,13 +40,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:11:5
    |
  9 | # error: [not-iterable]
 10 | for x in Iterable():
 11 |     reveal_type(x)  # revealed: int
-   |     ^^^^^^^^^^^^^^ Revealed type is `int`
+   |     ^^^^^^^^^^^^^^ `int`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_No_`__iter__`_method_and_`__getitem__`_is_not_callable.snap

@@ -37,13 +37,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
  --> /src/mdtest_snippet.py:8:5
   |
 6 | # error: [not-iterable]
 7 | for x in Bad():
 8 |     reveal_type(x)  # revealed: Unknown
-  |     ^^^^^^^^^^^^^^ Revealed type is `Unknown`
+  |     ^^^^^^^^^^^^^^ `Unknown`
   |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly-not-callable_`__getitem__`_method.snap

@@ -59,13 +59,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:24:9
    |
 22 |     for x in Iterable1():
 23 |         # TODO... `int` might be ideal here?
 24 |         reveal_type(x)  # revealed: int | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | Unknown`
+   |         ^^^^^^^^^^^^^^ `int | Unknown`
 25 |
 26 |     # error: [not-iterable]
    |
@@ -78,7 +78,7 @@ error: lint:not-iterable
    |
 26 |     # error: [not-iterable]
 27 |     for y in Iterable2():
-   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it has no `__iter__` method and its `__getitem__` attribute (with type `<bound method `__getitem__` of `Iterable2`> | None`) may not be callable
+   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it has no `__iter__` method and its `__getitem__` attribute (with type `(bound method Iterable2.__getitem__(key: int) -> int) | None`) may not be callable
 28 |         # TODO... `int` might be ideal here?
 29 |         reveal_type(y)  # revealed: int | Unknown
    |
@@ -86,13 +86,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:29:9
    |
 27 |     for y in Iterable2():
 28 |         # TODO... `int` might be ideal here?
 29 |         reveal_type(y)  # revealed: int | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | Unknown`
+   |         ^^^^^^^^^^^^^^ `int | Unknown`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_invalid_`__getitem__`_methods.snap

@@ -48,7 +48,7 @@ error: lint:not-iterable
    |
 19 |     # error: [not-iterable]
 20 |     for x in Iterable1():
-   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because it has no `__iter__` method and its `__getitem__` attribute (with type `<bound method `__getitem__` of `Iterable1`> | None`) may not be callable
+   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because it has no `__iter__` method and its `__getitem__` attribute (with type `(bound method Iterable1.__getitem__(item: int) -> str) | None`) may not be callable
 21 |         # TODO: `str` might be better
 22 |         reveal_type(x)  # revealed: str | Unknown
    |
@@ -56,13 +56,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:22:9
    |
 20 |     for x in Iterable1():
 21 |         # TODO: `str` might be better
 22 |         reveal_type(x)  # revealed: str | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `str | Unknown`
+   |         ^^^^^^^^^^^^^^ `str | Unknown`
 23 |
 24 |     # error: [not-iterable]
    |
@@ -75,20 +75,20 @@ error: lint:not-iterable
    |
 24 |     # error: [not-iterable]
 25 |     for y in Iterable2():
-   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it has no `__iter__` method and its `__getitem__` method (with type `<bound method `__getitem__` of `Iterable2`> | <bound method `__getitem__` of `Iterable2`>`) may have an incorrect signature for the old-style iteration protocol (expected a signature at least as permissive as `def __getitem__(self, key: int): ...`)
+   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it has no `__iter__` method and its `__getitem__` method (with type `(bound method Iterable2.__getitem__(item: int) -> str) | (bound method Iterable2.__getitem__(item: str) -> int)`) may have an incorrect signature for the old-style iteration protocol (expected a signature at least as permissive as `def __getitem__(self, key: int): ...`)
 26 |         reveal_type(y)  # revealed: str | int
    |
 
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:26:9
    |
 24 |     # error: [not-iterable]
 25 |     for y in Iterable2():
 26 |         reveal_type(y)  # revealed: str | int
-   |         ^^^^^^^^^^^^^^ Revealed type is `str | int`
+   |         ^^^^^^^^^^^^^^ `str | int`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_invalid_`__iter__`_methods.snap

@@ -52,20 +52,20 @@ error: lint:not-iterable
    |
 16 |     # error: [not-iterable]
 17 |     for x in Iterable1():
-   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because its `__iter__` method (with type `<bound method `__iter__` of `Iterable1`> | <bound method `__iter__` of `Iterable1`>`) may have an invalid signature (expected `def __iter__(self): ...`)
+   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because its `__iter__` method (with type `(bound method Iterable1.__iter__() -> Iterator) | (bound method Iterable1.__iter__(invalid_extra_arg) -> Iterator)`) may have an invalid signature (expected `def __iter__(self): ...`)
 18 |         reveal_type(x)  # revealed: int
    |
 
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:18:9
    |
 16 |     # error: [not-iterable]
 17 |     for x in Iterable1():
 18 |         reveal_type(x)  # revealed: int
-   |         ^^^^^^^^^^^^^^ Revealed type is `int`
+   |         ^^^^^^^^^^^^^^ `int`
 19 |
 20 |     class Iterable2:
    |
@@ -78,7 +78,7 @@ error: lint:not-iterable
    |
 27 |     # error: [not-iterable]
 28 |     for x in Iterable2():
-   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because its `__iter__` attribute (with type `<bound method `__iter__` of `Iterable2`> | None`) may not be callable
+   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because its `__iter__` attribute (with type `(bound method Iterable2.__iter__() -> Iterator) | None`) may not be callable
 29 |         # TODO: `int` would probably be better here:
 30 |         reveal_type(x)  # revealed: int | Unknown
    |
@@ -86,13 +86,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:30:9
    |
 28 |     for x in Iterable2():
 29 |         # TODO: `int` would probably be better here:
 30 |         reveal_type(x)  # revealed: int | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | Unknown`
+   |         ^^^^^^^^^^^^^^ `int | Unknown`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_invalid_`__next__`_method.snap

@@ -63,13 +63,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:29:9
    |
 27 |     # error: [not-iterable]
 28 |     for x in Iterable1():
 29 |         reveal_type(x)  # revealed: int | str
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | str`
+   |         ^^^^^^^^^^^^^^ `int | str`
 30 |
 31 |     # error: [not-iterable]
    |
@@ -90,13 +90,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:34:9
    |
 32 |     for y in Iterable2():
 33 |         # TODO: `int` would probably be better here:
 34 |         reveal_type(y)  # revealed: int | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | Unknown`
+   |         ^^^^^^^^^^^^^^ `int | Unknown`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_unbound_`__iter__`_and_bad_`__getitem__`_method.snap

@@ -48,13 +48,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:19:9
    |
 17 |     # error: [not-iterable]
 18 |     for x in Iterable():
 19 |         reveal_type(x)  # revealed: int | bytes
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | bytes`
+   |         ^^^^^^^^^^^^^^ `int | bytes`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_unbound_`__iter__`_and_possibly_invalid_`__getitem__`.snap

@@ -59,7 +59,7 @@ error: lint:not-iterable
    |
 30 |     # error: [not-iterable]
 31 |     for x in Iterable1():
-   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because it may not have an `__iter__` method and its `__getitem__` attribute (with type `<bound method `__getitem__` of `Iterable1`> | None`) may not be callable
+   |              ^^^^^^^^^^^ Object of type `Iterable1` may not be iterable because it may not have an `__iter__` method and its `__getitem__` attribute (with type `(bound method Iterable1.__getitem__(item: int) -> str) | None`) may not be callable
 32 |         # TODO: `bytes | str` might be better
 33 |         reveal_type(x)  # revealed: bytes | str | Unknown
    |
@@ -67,13 +67,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:33:9
    |
 31 |     for x in Iterable1():
 32 |         # TODO: `bytes | str` might be better
 33 |         reveal_type(x)  # revealed: bytes | str | Unknown
-   |         ^^^^^^^^^^^^^^ Revealed type is `bytes | str | Unknown`
+   |         ^^^^^^^^^^^^^^ `bytes | str | Unknown`
 34 |
 35 |     # error: [not-iterable]
    |
@@ -86,20 +86,20 @@ error: lint:not-iterable
    |
 35 |     # error: [not-iterable]
 36 |     for y in Iterable2():
-   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it may not have an `__iter__` method and its `__getitem__` method (with type `<bound method `__getitem__` of `Iterable2`> | <bound method `__getitem__` of `Iterable2`>`) may have an incorrect signature for the old-style iteration protocol (expected a signature at least as permissive as `def __getitem__(self, key: int): ...`)
+   |              ^^^^^^^^^^^ Object of type `Iterable2` may not be iterable because it may not have an `__iter__` method and its `__getitem__` method (with type `(bound method Iterable2.__getitem__(item: int) -> str) | (bound method Iterable2.__getitem__(item: str) -> int)`) may have an incorrect signature for the old-style iteration protocol (expected a signature at least as permissive as `def __getitem__(self, key: int): ...`)
 37 |         reveal_type(y)  # revealed: bytes | str | int
    |
 
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:37:9
    |
 35 |     # error: [not-iterable]
 36 |     for y in Iterable2():
 37 |         reveal_type(y)  # revealed: bytes | str | int
-   |         ^^^^^^^^^^^^^^ Revealed type is `bytes | str | int`
+   |         ^^^^^^^^^^^^^^ `bytes | str | int`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Possibly_unbound_`__iter__`_and_possibly_unbound_`__getitem__`.snap

@@ -47,13 +47,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:18:9
    |
 16 |     # error: [not-iterable]
 17 |     for x in Iterable():
 18 |         reveal_type(x)  # revealed: int | bytes
-   |         ^^^^^^^^^^^^^^ Revealed type is `int | bytes`
+   |         ^^^^^^^^^^^^^^ `int | bytes`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Union_type_as_iterable_where_one_union_element_has_invalid_`__iter__`_method.snap

@@ -49,13 +49,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:19:9
    |
 17 |     # error: [not-iterable]
 18 |     for x in Test() if flag else Test2():
 19 |         reveal_type(x)  # revealed: int
-   |         ^^^^^^^^^^^^^^ Revealed type is `int`
+   |         ^^^^^^^^^^^^^^ `int`
    |
 
 ```

crates/red_knot_python_semantic/resources/mdtest/snapshots/for.md_-_For_loops_-_Union_type_as_iterable_where_one_union_element_has_no_`__iter__`_method.snap

@@ -44,13 +44,13 @@ error: lint:not-iterable
 ```
 
 ```
-info: revealed-type
+info: revealed-type: Revealed type
   --> /src/mdtest_snippet.py:14:9
    |
 12 |     # error: [not-iterable]
 13 |     for x in Test() if flag else 42:
 14 |         reveal_type(x)  # revealed: int
-   |         ^^^^^^^^^^^^^^ Revealed type is `int`
+   |         ^^^^^^^^^^^^^^ `int`
    |
 
 ```