Experiment with Located trait

.github/CODEOWNERS

@@ -17,5 +17,5 @@
 /scripts/fuzz-parser/ @AlexWaygood
 
 # red-knot
-/crates/red_knot* @carljm @MichaReiser @AlexWaygood @sharkdp
-/crates/ruff_db/ @carljm @MichaReiser @AlexWaygood @sharkdp
+/crates/red_knot* @carljm @MichaReiser @AlexWaygood
+/crates/ruff_db/ @carljm @MichaReiser @AlexWaygood

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ env:
   CARGO_TERM_COLOR: always
   RUSTUP_MAX_RETRIES: 10
   PACKAGE_NAME: ruff
-  PYTHON_VERSION: "3.12"
+  PYTHON_VERSION: "3.11"
 
 jobs:
   determine_changes:

.github/workflows/publish-playground.yml

@@ -47,7 +47,7 @@ jobs:
         working-directory: playground
       - name: "Deploy to Cloudflare Pages"
         if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@v3.11.0
+        uses: cloudflare/wrangler-action@v3.9.0
         with:
           apiToken: ${{ secrets.CF_API_TOKEN }}
           accountId: ${{ secrets.CF_ACCOUNT_ID }}

.github/workflows/publish-pypi.yml

@@ -21,12 +21,14 @@ jobs:
       # For PyPI's trusted publishing.
       id-token: write
     steps:
-      - name: "Install uv"
-        uses: astral-sh/setup-uv@v3
       - uses: actions/download-artifact@v4
         with:
           pattern: wheels-*
           path: wheels
           merge-multiple: true
       - name: Publish to PyPi
-        run: uv publish -v wheels/*
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          skip-existing: true
+          packages-dir: wheels
+          verbose: true

.pre-commit-config.yaml

@@ -17,7 +17,7 @@ exclude: |
 
 repos:
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.22
+    rev: v0.21
     hooks:
       - id: validate-pyproject
 
@@ -51,15 +51,11 @@ repos:
       - id: blacken-docs
         args: ["--pyi", "--line-length", "130"]
         files: '^crates/.*/resources/mdtest/.*\.md'
-        exclude: |
-          (?x)^(
-            .*?invalid(_.+)_syntax.md
-          )$
         additional_dependencies:
           - black==24.10.0
 
   - repo: https://github.com/crate-ci/typos
-    rev: v1.27.0
+    rev: v1.26.0
     hooks:
       - id: typos
 
@@ -73,7 +69,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.7.2
+    rev: v0.7.0
     hooks:
       - id: ruff-format
       - id: ruff

CHANGELOG.md

@@ -1,68 +1,5 @@
 # Changelog
 
-## 0.7.3
-
-### Preview features
-
-- Formatter: Disallow single-line implicit concatenated strings ([#13928](https://github.com/astral-sh/ruff/pull/13928))
-- \[`flake8-pyi`\] Include all Python file types for `PYI006` and `PYI066` ([#14059](https://github.com/astral-sh/ruff/pull/14059))
-- \[`flake8-simplify`\] Implement `split-of-static-string` (`SIM905`) ([#14008](https://github.com/astral-sh/ruff/pull/14008))
-- \[`refurb`\] Implement `subclass-builtin` (`FURB189`) ([#14105](https://github.com/astral-sh/ruff/pull/14105))
-- \[`ruff`\] Improve diagnostic messages and docs (`RUF031`, `RUF032`, `RUF034`) ([#14068](https://github.com/astral-sh/ruff/pull/14068))
-
-### Rule changes
-
-- Detect items that hash to same value in duplicate sets (`B033`, `PLC0208`) ([#14064](https://github.com/astral-sh/ruff/pull/14064))
-- \[`eradicate`\] Better detection of IntelliJ language injection comments (`ERA001`) ([#14094](https://github.com/astral-sh/ruff/pull/14094))
-- \[`flake8-pyi`\] Add autofix for `docstring-in-stub` (`PYI021`) ([#14150](https://github.com/astral-sh/ruff/pull/14150))
-- \[`flake8-pyi`\] Update `duplicate-literal-member` (`PYI062`) to alawys provide an autofix ([#14188](https://github.com/astral-sh/ruff/pull/14188))
-- \[`pyflakes`\] Detect items that hash to same value in duplicate dictionaries (`F601`) ([#14065](https://github.com/astral-sh/ruff/pull/14065))
-- \[`ruff`\] Fix false positive for decorators (`RUF028`) ([#14061](https://github.com/astral-sh/ruff/pull/14061))
-
-### Bug fixes
-
-- Avoid parsing joint rule codes as distinct codes in `# noqa` ([#12809](https://github.com/astral-sh/ruff/pull/12809))
-- \[`eradicate`\] ignore `# language=` in commented-out-code rule (ERA001) ([#14069](https://github.com/astral-sh/ruff/pull/14069))
-- \[`flake8-bugbear`\] - do not run `mutable-argument-default` on stubs (`B006`) ([#14058](https://github.com/astral-sh/ruff/pull/14058))
-- \[`flake8-builtins`\] Skip lambda expressions in `builtin-argument-shadowing (A002)` ([#14144](https://github.com/astral-sh/ruff/pull/14144))
-- \[`flake8-comprehension`\] Also remove trailing comma while fixing `C409` and `C419` ([#14097](https://github.com/astral-sh/ruff/pull/14097))
-- \[`flake8-simplify`\] Allow `open` without context manager in `return` statement (`SIM115`) ([#14066](https://github.com/astral-sh/ruff/pull/14066))
-- \[`pylint`\] Respect hash-equivalent literals in `iteration-over-set` (`PLC0208`) ([#14063](https://github.com/astral-sh/ruff/pull/14063))
-- \[`pylint`\] Update known dunder methods for Python 3.13 (`PLW3201`) ([#14146](https://github.com/astral-sh/ruff/pull/14146))
-- \[`pyupgrade`\] - ignore kwarg unpacking for `UP044` ([#14053](https://github.com/astral-sh/ruff/pull/14053))
-- \[`refurb`\] Parse more exotic decimal strings in `verbose-decimal-constructor` (`FURB157`) ([#14098](https://github.com/astral-sh/ruff/pull/14098))
-
-### Documentation
-
-- Add links to missing related options within rule documentations ([#13971](https://github.com/astral-sh/ruff/pull/13971))
-- Add rule short code to mkdocs tags to allow searching via rule codes ([#14040](https://github.com/astral-sh/ruff/pull/14040))
-
-## 0.7.2
-
-### Preview features
-
-- Fix formatting of single with-item with trailing comment ([#14005](https://github.com/astral-sh/ruff/pull/14005))
-- \[`pyupgrade`\] Add PEP 646 `Unpack` conversion to `*` with fix (`UP044`) ([#13988](https://github.com/astral-sh/ruff/pull/13988))
-
-### Rule changes
-
-- Regenerate `known_stdlibs.rs` with stdlibs 2024.10.25 ([#13963](https://github.com/astral-sh/ruff/pull/13963))
-- \[`flake8-no-pep420`\] Skip namespace package enforcement for PEP 723 scripts (`INP001`) ([#13974](https://github.com/astral-sh/ruff/pull/13974))
-
-### Server
-
-- Fix server panic when undoing an edit ([#14010](https://github.com/astral-sh/ruff/pull/14010))
-
-### Bug fixes
-
-- Fix issues in discovering ruff in pip build environments ([#13881](https://github.com/astral-sh/ruff/pull/13881))
-- \[`flake8-type-checking`\] Fix false positive for `singledispatchmethod` (`TCH003`) ([#13941](https://github.com/astral-sh/ruff/pull/13941))
-- \[`flake8-type-checking`\] Treat return type of `singledispatch` as runtime-required (`TCH003`) ([#13957](https://github.com/astral-sh/ruff/pull/13957))
-
-### Documentation
-
-- \[`flake8-simplify`\] Include caveats of enabling `if-else-block-instead-of-if-exp` (`SIM108`) ([#14019](https://github.com/astral-sh/ruff/pull/14019))
-
 ## 0.7.1
 
 ### Preview features

Cargo.lock

@@ -123,9 +123,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.92"
+version = "1.0.90"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74f37166d7d48a0284b99dd824694c26119c700b53bf0d1540cdb147dbdaaf13"
+checksum = "37bf3594c4c988a53154954629820791dde498571819ae4ca50ca811e060cc95"
 
 [[package]]
 name = "append-only-vec"
@@ -407,7 +407,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -687,7 +687,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "strsim 0.10.0",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -698,7 +698,7 @@ checksum = "a668eda54683121533a393014d8692171709ff57a7d61f187b6e782719f8933f"
 dependencies = [
  "darling_core",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -1162,12 +1162,12 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "2.6.0"
+version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "707907fe3c25f5424cce2cb7e1cbcafee6bdbe735ca90ef77c29e84591e5b9da"
+checksum = "68b900aa2f7301e21c36462b170ee99994de34dff39a4a6a528e80e7376d07e5"
 dependencies = [
  "equivalent",
- "hashbrown 0.15.0",
+ "hashbrown 0.14.5",
  "serde",
 ]
 
@@ -1193,9 +1193,9 @@ checksum = "b248f5224d1d606005e02c97f5aa4e88eeb230488bcc03bc9ca4d7991399f2b5"
 
 [[package]]
 name = "inotify"
-version = "0.10.2"
+version = "0.9.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fdd168d97690d0b8c412d6b6c10360277f4d7ee495c5d0d5d5fe0854923255cc"
+checksum = "f8069d3ec154eb856955c1c0fbffefbf5f3c40a104ec912d4797314c1801abff"
 dependencies = [
  "bitflags 1.3.2",
  "inotify-sys",
@@ -1213,9 +1213,9 @@ dependencies = [
 
 [[package]]
 name = "insta"
-version = "1.41.1"
+version = "1.40.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e9ffc4d4892617c50a928c52b2961cb5174b6fc6ebf252b2fac9d21955c48b8"
+checksum = "6593a41c7a73841868772495db7dc1e8ecab43bb5c0b6da2059246c4b506ab60"
 dependencies = [
  "console",
  "globset",
@@ -1267,7 +1267,7 @@ dependencies = [
  "Inflector",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -1393,7 +1393,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2ae40017ac09cd2c6a53504cb3c871c7f2b41466eac5bc66ba63f39073b467b"
 dependencies = [
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -1532,15 +1532,14 @@ dependencies = [
 
 [[package]]
 name = "mio"
-version = "1.0.2"
+version = "0.8.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80e04d1dcff3aae0704555fe5fee3bcfaf3d1fdf8a7e521d5b9d2b42acb52cec"
+checksum = "a4a650543ca06a924e8b371db273b2756685faae30f8487da1b56505a8f78b0c"
 dependencies = [
- "hermit-abi",
  "libc",
  "log",
  "wasi",
- "windows-sys 0.52.0",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]
@@ -1594,11 +1593,12 @@ dependencies = [
 
 [[package]]
 name = "notify"
-version = "7.0.0"
+version = "6.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c533b4c39709f9ba5005d8002048266593c1cfaf3c5f0739d5b8ab0c6c504009"
+checksum = "6205bd8bb1e454ad2e27422015fb5e4f2bcc7e08fa8f27058670d208324a4d2d"
 dependencies = [
  "bitflags 2.6.0",
+ "crossbeam-channel",
  "filetime",
  "fsevent-sys",
  "inotify",
@@ -1606,18 +1606,8 @@ dependencies = [
  "libc",
  "log",
  "mio",
- "notify-types",
  "walkdir",
- "windows-sys 0.52.0",
-]
-
-[[package]]
-name = "notify-types"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7393c226621f817964ffb3dc5704f9509e107a8b024b489cc2c1b217378785df"
-dependencies = [
- "instant",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]
@@ -1796,9 +1786,9 @@ dependencies = [
 
 [[package]]
 name = "pep440_rs"
-version = "0.7.2"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0922a442c78611fa8c5ed6065d2d898a820cf12fa90604217fdb2d01675efec7"
+checksum = "7c8ee724d21f351f9d47276614ac9710975db827ba9fe2ca5a517ba648193307"
 dependencies = [
  "serde",
  "unicode-width 0.2.0",
@@ -1858,7 +1848,7 @@ dependencies = [
  "pest_meta",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -1973,9 +1963,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.89"
+version = "1.0.88"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f139b0662de085916d1fb67d2b4169d1addddda1919e696f3252b740b629986e"
+checksum = "7c3a7fc5db1e57d5a779a352c8cdb57b29aa4c40cc69c3a68a7fedc815fbf2f9"
 dependencies = [
  "unicode-ident",
 ]
@@ -2112,7 +2102,6 @@ dependencies = [
  "countme",
  "dir-test",
  "hashbrown 0.15.0",
- "indexmap",
  "insta",
  "itertools 0.13.0",
  "memchr",
@@ -2258,9 +2247,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.11.1"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+checksum = "38200e5ee88914975b69f657f0801b6f6dccafd44fd9326302a4aaeecfacb1d8"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -2317,7 +2306,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.7.3"
+version = "0.7.1"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2534,7 +2523,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.7.3"
+version = "0.7.1"
 dependencies = [
  "aho-corasick",
  "annotate-snippets 0.9.2",
@@ -2557,7 +2546,7 @@ dependencies = [
  "natord",
  "path-absolutize",
  "pathdiff",
- "pep440_rs 0.7.2",
+ "pep440_rs 0.7.1",
  "pyproject-toml",
  "quick-junit",
  "regex",
@@ -2601,7 +2590,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "ruff_python_trivia",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -2631,14 +2620,12 @@ dependencies = [
  "compact_str",
  "is-macro",
  "itertools 0.13.0",
- "memchr",
  "ruff_cache",
  "ruff_macros",
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash 2.0.0",
- "salsa",
  "schemars",
  "serde",
 ]
@@ -2761,6 +2748,7 @@ dependencies = [
  "ruff_python_ast",
  "ruff_python_parser",
  "ruff_python_stdlib",
+ "ruff_source_file",
  "ruff_text_size",
  "rustc-hash 2.0.0",
  "schemars",
@@ -2791,6 +2779,7 @@ dependencies = [
  "insta",
  "ruff_python_parser",
  "ruff_python_trivia",
+ "ruff_source_file",
  "ruff_text_size",
 ]
 
@@ -2849,7 +2838,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.7.3"
+version = "0.7.1"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -2888,7 +2877,7 @@ dependencies = [
  "matchit",
  "path-absolutize",
  "path-slash",
- "pep440_rs 0.7.2",
+ "pep440_rs 0.7.1",
  "regex",
  "ruff_cache",
  "ruff_formatter",
@@ -3020,7 +3009,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
  "synstructure",
 ]
 
@@ -3054,7 +3043,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde_derive_internals",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3077,9 +3066,9 @@ checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"
 
 [[package]]
 name = "serde"
-version = "1.0.214"
+version = "1.0.210"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f55c3193aca71c12ad7890f1785d2b73e1b9f63a0bbc353c08ef26fe03fc56b5"
+checksum = "c8e3592472072e6e22e0a54d5904d9febf8508f65fb8552499a1abc7d1078c3a"
 dependencies = [
  "serde_derive",
 ]
@@ -3097,13 +3086,13 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.214"
+version = "1.0.210"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de523f781f095e28fa605cdce0f8307e451cc0fd14e2eb4cd2e98a355b147766"
+checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3114,7 +3103,7 @@ checksum = "330f01ce65a3a5fe59a60c82f3c9a024b573b8a6e875bd233fe5f934e71d54e3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3137,7 +3126,7 @@ checksum = "6c64451ba24fc7a6a2d60fc75dd9c83c90903b19028d4eff35e88fc1e86564e9"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3178,7 +3167,7 @@ dependencies = [
  "darling",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3280,7 +3269,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "rustversion",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3302,9 +3291,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.87"
+version = "2.0.82"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25aa4ce346d03a6dcd68dd8b4010bcb74e54e62c90c573f394c46eae99aba32d"
+checksum = "83540f837a8afc019423a8edb95b52a8effe46957ee402287f4292fae35be021"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3319,7 +3308,7 @@ checksum = "c8af7666ab7b6390ab78131fb5b0fce11d6b7a6951602017c35fa82800708971"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3382,7 +3371,7 @@ dependencies = [
  "cfg-if",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3393,28 +3382,28 @@ checksum = "5c89e72a01ed4c579669add59014b9a524d609c0c88c6a585ce37485879f6ffb"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
  "test-case-core",
 ]
 
 [[package]]
 name = "thiserror"
-version = "1.0.67"
+version = "1.0.64"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b3c6efbfc763e64eb85c11c25320f0737cb7364c4b6336db90aa9ebe27a0bbd"
+checksum = "d50af8abc119fb8bb6dbabcfa89656f46f84aa0ac7688088608076ad2b459a84"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.67"
+version = "1.0.64"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b607164372e89797d78b8e23a6d67d5d1038c1c65efd52e1389ef8b77caba2a6"
+checksum = "08904e7672f5eb876eaaf87e0ce17857500934f4981c4a0ab2b4aa98baac7fc3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3526,7 +3515,7 @@ checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3784,7 +3773,7 @@ checksum = "6b91f57fe13a38d0ce9e28a03463d8d3c2468ed03d75375110ec71d93b449a08"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -3870,7 +3859,7 @@ dependencies = [
  "once_cell",
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
  "wasm-bindgen-shared",
 ]
 
@@ -3904,7 +3893,7 @@ checksum = "26c6ab57572f7a24a4985830b120de1594465e5d500f24afe89e16b4e833ef68"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
  "wasm-bindgen-backend",
  "wasm-bindgen-shared",
 ]
@@ -3938,7 +3927,7 @@ checksum = "c97b2ef2c8d627381e51c071c2ab328eac606d3f69dd82bcbca20a9e389d95f0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]
@@ -4226,7 +4215,7 @@ checksum = "9ce1b18ccd8e73a9321186f97e46f9f04b778851177567b1975109d26a08d2a6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.87",
+ "syn 2.0.82",
 ]
 
 [[package]]

Cargo.toml

@@ -81,7 +81,6 @@ hashbrown = { version = "0.15.0", default-features = false, features = [
 ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
 imperative = { version = "1.0.4" }
-indexmap = {version = "2.6.0" }
 indicatif = { version = "0.17.8" }
 indoc = { version = "2.0.4" }
 insta = { version = "1.35.1" }
@@ -102,7 +101,7 @@ matchit = { version = "0.8.1" }
 memchr = { version = "2.7.1" }
 mimalloc = { version = "0.1.39" }
 natord = { version = "1.0.9" }
-notify = { version = "7.0.0" }
+notify = { version = "6.1.1" }
 ordermap = { version = "0.5.0" }
 path-absolutize = { version = "3.1.1" }
 path-slash = { version = "0.2.1" }
@@ -189,9 +188,8 @@ missing_panics_doc = "allow"
 module_name_repetitions = "allow"
 must_use_candidate = "allow"
 similar_names = "allow"
-single_match_else = "allow"
 too_many_lines = "allow"
-# Without the hashes we run into a `rustfmt` bug in some snapshot tests, see #13250
+# To allow `#[allow(clippy::all)]` in `crates/ruff_python_parser/src/python.rs`.
 needless_raw_string_hashes = "allow"
 # Disallowed restriction lints
 print_stdout = "warn"

README.md

@@ -136,8 +136,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
 
 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.7.3/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.7.3/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.7.1/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.7.1/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -170,7 +170,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.7.3
+  rev: v0.7.1
   hooks:
     # Run the linter.
     - id: ruff
@@ -417,7 +417,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Babel](https://github.com/python-babel/babel)
 - Benchling ([Refac](https://github.com/benchling/refac))
 - [Bokeh](https://github.com/bokeh/bokeh)
-- CrowdCent ([NumerBlox](https://github.com/crowdcent/numerblox)) <!-- typos: ignore -->
 - [Cryptography (PyCA)](https://github.com/pyca/cryptography)
 - CERN ([Indico](https://getindico.io/))
 - [DVC](https://github.com/iterative/dvc)

_typos.toml

@@ -12,7 +12,6 @@ pn = "pn"  # `import panel as pn` is a thing
 poit = "poit"
 BA = "BA" # acronym for "Bad Allowed", used in testing.
 jod = "jod" # e.g., `jod-thread`
-Numer = "Numer" # Library name 'NumerBlox' in "Who's Using Ruff?"
 
 [default]
 extend-ignore-re = [

crates/red_knot/src/main.rs

@@ -5,6 +5,8 @@ use anyhow::{anyhow, Context};
 use clap::Parser;
 use colored::Colorize;
 use crossbeam::channel as crossbeam_channel;
+use salsa::plumbing::ZalsaDatabase;
+
 use red_knot_python_semantic::SitePackages;
 use red_knot_server::run_server;
 use red_knot_workspace::db::RootDatabase;
@@ -12,9 +14,7 @@ use red_knot_workspace::watch;
 use red_knot_workspace::watch::WorkspaceWatcher;
 use red_knot_workspace::workspace::settings::Configuration;
 use red_knot_workspace::workspace::WorkspaceMetadata;
-use ruff_db::diagnostic::Diagnostic;
 use ruff_db::system::{OsSystem, System, SystemPath, SystemPathBuf};
-use salsa::plumbing::ZalsaDatabase;
 use target_version::TargetVersion;
 
 use crate::logging::{setup_tracing, Verbosity};
@@ -318,9 +318,8 @@ impl MainLoop {
                 } => {
                     let has_diagnostics = !result.is_empty();
                     if check_revision == revision {
-                        #[allow(clippy::print_stdout)]
                         for diagnostic in result {
-                            println!("{}", diagnostic.display(db));
+                            tracing::error!("{}", diagnostic);
                         }
                     } else {
                         tracing::debug!(
@@ -379,10 +378,7 @@ impl MainLoopCancellationToken {
 #[derive(Debug)]
 enum MainLoopMessage {
     CheckWorkspace,
-    CheckCompleted {
-        result: Vec<Box<dyn Diagnostic>>,
-        revision: u64,
-    },
+    CheckCompleted { result: Vec<String>, revision: u64 },
     ApplyChanges(Vec<watch::ChangeEvent>),
     Exit,
 }

crates/red_knot_python_semantic/Cargo.toml

@@ -13,7 +13,7 @@ license = { workspace = true }
 [dependencies]
 ruff_db = { workspace = true }
 ruff_index = { workspace = true }
-ruff_python_ast = { workspace = true, features = ["salsa"] }
+ruff_python_ast = { workspace = true }
 ruff_python_stdlib = { workspace = true }
 ruff_source_file = { workspace = true }
 ruff_text_size = { workspace = true }
@@ -24,8 +24,7 @@ bitflags = { workspace = true }
 camino = { workspace = true }
 compact_str = { workspace = true }
 countme = { workspace = true }
-indexmap = { workspace = true }
-itertools = { workspace = true }
+itertools = { workspace = true}
 ordermap = { workspace = true }
 salsa = { workspace = true }
 thiserror = { workspace = true }
@@ -44,9 +43,10 @@ red_knot_test = { workspace = true }
 red_knot_vendored = { workspace = true }
 
 anyhow = { workspace = true }
-dir-test = { workspace = true }
+dir-test = {workspace = true}
 insta = { workspace = true }
 tempfile = { workspace = true }
 
 [lints]
 workspace = true
+

crates/red_knot_python_semantic/resources/mdtest/.mdformat.toml

@@ -1 +0,0 @@
-wrap = 100

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

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

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

@@ -1,9 +0,0 @@
-# String annotations
-
-```py
-def f() -> "int":
-    return 1
-
-# TODO: We do not support string annotations, but we should not panic if we encounter them
-reveal_type(f())  # revealed: @Todo
-```

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

@@ -23,90 +23,12 @@ x: int
 x = "foo"  # error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `int`"
 ```
 
-## Tuple annotations are understood
-
-```py path=module.py
-from typing_extensions import Unpack
-
-a: tuple[()] = ()
-b: tuple[int] = (42,)
-c: tuple[str, int] = ("42", 42)
-d: tuple[tuple[str, str], tuple[int, int]] = (("foo", "foo"), (42, 42))
-e: tuple[str, ...] = ()
-# TODO: we should not emit this error
-# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[tuple]` is possibly unbound"
-f: tuple[str, *tuple[int, ...], bytes] = ("42", b"42")
-g: tuple[str, Unpack[tuple[int, ...]], bytes] = ("42", b"42")
-h: tuple[list[int], list[int]] = ([], [])
-i: tuple[str | int, str | int] = (42, 42)
-j: tuple[str | int] = (42,)
-```
-
-```py path=script.py
-from module import a, b, c, d, e, f, g, h, i, j
-
-reveal_type(a)  # revealed: tuple[()]
-reveal_type(b)  # revealed: tuple[int]
-reveal_type(c)  # revealed: tuple[str, int]
-reveal_type(d)  # revealed: tuple[tuple[str, str], tuple[int, int]]
-
-# TODO: homogenous tuples, PEP-646 tuples
-reveal_type(e)  # revealed: @Todo
-reveal_type(f)  # revealed: @Todo
-reveal_type(g)  # revealed: @Todo
-
-# TODO: support more kinds of type expressions in annotations
-reveal_type(h)  # revealed: @Todo
-
-reveal_type(i)  # revealed: tuple[str | int, str | int]
-reveal_type(j)  # revealed: tuple[str | int]
-```
-
-## Incorrect tuple assignments are complained about
+## PEP-604 annotations not yet supported
 
 ```py
-# error: [invalid-assignment] "Object of type `tuple[Literal[1], Literal[2]]` is not assignable to `tuple[()]`"
-a: tuple[()] = (1, 2)
-
-# error: [invalid-assignment] "Object of type `tuple[Literal["foo"]]` is not assignable to `tuple[int]`"
-b: tuple[int] = ("foo",)
-
-# error: [invalid-assignment] "Object of type `tuple[list, Literal["foo"]]` is not assignable to `tuple[str | int, str]`"
-c: tuple[str | int, str] = ([], "foo")
-```
-
-## PEP-604 annotations are supported
-
-```py
-def foo() -> str | int | None:
+def f() -> str | None:
     return None
 
-reveal_type(foo())  # revealed: str | int | None
-
-def bar() -> str | str | None:
-    return None
-
-reveal_type(bar())  # revealed: str | None
-
-def baz() -> str | str:
-    return "Hello, world!"
-
-reveal_type(baz())  # revealed: str
-```
-
-## Attribute expressions in type annotations are understood
-
-```py
-import builtins
-
-int = "foo"
-a: builtins.int = 42
-
-# error: [invalid-assignment] "Object of type `Literal["bar"]` is not assignable to `int`"
-b: builtins.int = "bar"
-
-c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = ((42, 42), 42)
-
-# error: [invalid-assignment] "Object of type `Literal["foo"]` is not assignable to `tuple[tuple[int, int], int]`"
-c: builtins.tuple[builtins.tuple[builtins.int, builtins.int], builtins.int] = "foo"
+# TODO: should be `str | None` (but Todo is better than `Unknown`)
+reveal_type(f())  # revealed: @Todo
 ```

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

@@ -1,182 +0,0 @@
-# Augmented assignment
-
-## Basic
-
-```py
-x = 3
-x -= 1
-reveal_type(x)  # revealed: Literal[2]
-
-x = 1.0
-x /= 2
-reveal_type(x)  # revealed: float
-```
-
-## Dunder methods
-
-```py
-class C:
-    def __isub__(self, other: int) -> str:
-        return "Hello, world!"
-
-x = C()
-x -= 1
-reveal_type(x)  # revealed: str
-
-class C:
-    def __iadd__(self, other: str) -> float:
-        return 1.0
-
-x = C()
-x += "Hello"
-reveal_type(x)  # revealed: float
-```
-
-## Unsupported types
-
-```py
-class C:
-    def __isub__(self, other: str) -> int:
-        return 42
-
-x = C()
-x -= 1
-
-# TODO: should error, once operand type check is implemented
-reveal_type(x)  # revealed: int
-```
-
-## Method union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    if bool_instance():
-        def __iadd__(self, other: int) -> str:
-            return "Hello, world!"
-    else:
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-f = Foo()
-f += 12
-
-reveal_type(f)  # revealed: str | int
-```
-
-## Partially bound `__iadd__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    if bool_instance():
-        def __iadd__(self, other: str) -> int:
-            return 42
-
-f = Foo()
-
-# TODO: We should emit an `unsupported-operator` error here, possibly with the information
-# that `Foo.__iadd__` may be unbound as additional context.
-f += "Hello, world!"
-
-reveal_type(f)  # revealed: int | Unknown
-```
-
-## Partially bound with `__add__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    def __add__(self, other: str) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: str) -> int:
-            return 42
-
-f = Foo()
-f += "Hello, world!"
-
-reveal_type(f)  # revealed: int | str
-```
-
-## Partially bound target union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class Foo:
-    def __add__(self, other: int) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-if bool_instance():
-    f = Foo()
-else:
-    f = 42.0
-f += 12
-
-reveal_type(f)  # revealed: int | str | float
-```
-
-## Target union
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    def __iadd__(self, other: int) -> str:
-        return "Hello, world!"
-
-if flag:
-    f = Foo()
-else:
-    f = 42.0
-f += 12
-
-reveal_type(f)  # revealed: str | float
-```
-
-## Partially bound target union with `__add__`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-class Foo:
-    def __add__(self, other: int) -> str:
-        return "Hello, world!"
-    if bool_instance():
-        def __iadd__(self, other: int) -> int:
-            return 42
-
-class Bar:
-    def __add__(self, other: int) -> bytes:
-        return b"Hello, world!"
-
-    def __iadd__(self, other: int) -> float:
-        return 42.0
-
-if flag:
-    f = Foo()
-else:
-    f = Bar()
-f += 12
-
-reveal_type(f)  # revealed: int | str | float
-```

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

@@ -6,19 +6,11 @@
 x = foo  # error: [unresolved-reference] "Name `foo` used when not defined"
 foo = 1
 
-# No error `unresolved-reference` diagnostic is reported for `x`. This is
-# desirable because we would get a lot of cascading errors even though there
-# is only one root cause (the unbound variable `foo`).
-
-# revealed: Unknown
+# error: [unresolved-reference]
+# revealed: Unbound
 reveal_type(x)
 ```
 
-Note: in this particular example, one could argue that the most likely error would be a wrong order
-of the `x`/`foo` definitions, and so it could be desirable to infer `Literal[1]` for the type of
-`x`. On the other hand, there might be a variable `fob` a little higher up in this file, and the
-actual error might have been just a typo. Inferring `Unknown` thus seems like the safest option.
-
 ## Unbound class variable
 
 Name lookups within a class scope fall back to globals, but lookups of class attributes don't.
@@ -38,22 +30,3 @@ class C:
 reveal_type(C.x)  # revealed: Literal[2]
 reveal_type(C.y)  # revealed: Literal[1]
 ```
-
-## Possibly unbound in class and global scope
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance():
-    x = "abc"
-
-class C:
-    if bool_instance():
-        x = 1
-
-    # error: [possibly-unresolved-reference]
-    y = x
-
-reveal_type(C.y)  # revealed: Literal[1] | Literal["abc"]
-```

crates/red_knot_python_semantic/resources/mdtest/attributes.md

@@ -18,38 +18,3 @@ else:
 
 reveal_type(C.x)  # revealed: Literal[1, 2]
 ```
-
-## Inherited attributes
-
-```py
-class A:
-    X = "foo"
-
-class B(A): ...
-class C(B): ...
-
-reveal_type(C.X)  # revealed: Literal["foo"]
-```
-
-## Inherited attributes (multiple inheritance)
-
-```py
-class O: ...
-
-class F(O):
-    X = 56
-
-class E(O):
-    X = 42
-
-class D(O): ...
-class C(D, F): ...
-class B(E, D): ...
-class A(B, C): ...
-
-# revealed: tuple[Literal[A], Literal[B], Literal[E], Literal[C], Literal[D], Literal[F], Literal[O], Literal[object]]
-reveal_type(A.__mro__)
-
-# `E` is earlier in the MRO than `F`, so we should use the type of `E.X`
-reveal_type(A.X)  # revealed: Literal[42]
-```

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

@@ -9,8 +9,8 @@ For references, see:
 
 ## Operations
 
-We support inference for all Python's binary operators: `+`, `-`, `*`, `@`, `/`, `//`, `%`, `**`,
-`<<`, `>>`, `&`, `^`, and `|`.
+We support inference for all Python's binary operators:
+`+`, `-`, `*`, `@`, `/`, `//`, `%`, `**`, `<<`, `>>`, `&`, `^`, and `|`.
 
 ```py
 class A:
@@ -152,8 +152,9 @@ reveal_type(B() - A())  # revealed: int
 
 ## Non-reflected precedence in general
 
-In general, if the left-hand side defines `__add__` and the right-hand side defines `__radd__` and
-the right-hand side is not a subtype of the left-hand side, `lhs.__add__` will take precedence:
+In general, if the left-hand side defines `__add__` and the right-hand side
+defines `__radd__` and the right-hand side is not a subtype of the left-hand
+side, `lhs.__add__` will take precedence:
 
 ```py
 class A:
@@ -180,8 +181,9 @@ reveal_type(C() + C())  # revealed: int
 
 ## Reflected precedence for subtypes (in some cases)
 
-If the right-hand operand is a subtype of the left-hand operand and has a different implementation
-of the reflected method, the reflected method on the right-hand operand takes precedence.
+If the right-hand operand is a subtype of the left-hand operand and has a
+different implementation of the reflected method, the reflected method on the
+right-hand operand takes precedence.
 
 ```py
 class A:
@@ -202,13 +204,18 @@ reveal_type(A() + B())  # revealed: MyString
 # N.B. Still a subtype of `A`, even though `A` does not appear directly in the class's `__bases__`
 class C(B): ...
 
-reveal_type(A() + C())  # revealed: MyString
+# TODO: we currently only understand direct subclasses as subtypes of the superclass.
+# We need to iterate through the full MRO rather than just the class's bases;
+# if we do, we'll understand `C` as a subtype of `A`, and correctly understand this as being
+# `MyString` rather than `str`
+reveal_type(A() + C())  # revealed: str
 ```
 
 ## Reflected precedence 2
 
-If the right-hand operand is a subtype of the left-hand operand, but does not override the reflected
-method, the left-hand operand's non-reflected method still takes precedence:
+If the right-hand operand is a subtype of the left-hand operand, but does not
+override the reflected method, the left-hand operand's non-reflected method
+still takes precedence:
 
 ```py
 class A:
@@ -225,15 +232,17 @@ reveal_type(A() + B())  # revealed: str
 
 ## Only reflected supported
 
-For example, at runtime, `(1).__add__(1.2)` is `NotImplemented`, but `(1.2).__radd__(1) == 2.2`,
-meaning that `1 + 1.2` succeeds at runtime (producing `2.2`). The runtime tries the second one only
-if the first one returns `NotImplemented` to signal failure.
+For example, at runtime, `(1).__add__(1.2)` is `NotImplemented`, but
+`(1.2).__radd__(1) == 2.2`, meaning that `1 + 1.2` succeeds at runtime
+(producing `2.2`). The runtime tries the second one only if the first one
+returns `NotImplemented` to signal failure.
 
-Typeshed and other stubs annotate dunder-method calls that would return `NotImplemented` as being
-"illegal" calls. `int.__add__` is annotated as only "accepting" `int`s, even though it
-strictly-speaking "accepts" any other object without raising an exception -- it will simply return
-`NotImplemented`, allowing the runtime to try the `__radd__` method of the right-hand operand as
-well.
+Typeshed and other stubs annotate dunder-method calls that would return
+`NotImplemented` as being "illegal" calls. `int.__add__` is annotated as only
+"accepting" `int`s, even though it strictly-speaking "accepts" any other object
+without raising an exception -- it will simply return `NotImplemented`,
+allowing the runtime to try the `__radd__` method of the right-hand operand
+as well.
 
 ```py
 class A:
@@ -299,8 +308,8 @@ reveal_type(y + 4.12)  # revealed: int
 
 ## With literal types
 
-When we have a literal type for one operand, we're able to fall back to the instance handling for
-its instance super-type.
+When we have a literal type for one operand, we're able to fall back to the
+instance handling for its instance super-type.
 
 ```py
 class A:
@@ -339,13 +348,15 @@ reveal_type(literal_string_instance + A())  # revealed: @Todo
 
 ## Operations involving instances of classes inheriting from `Any`
 
-`Any` and `Unknown` represent a set of possible runtime objects, wherein the bounds of the set are
-unknown. Whether the left-hand operand's dunder or the right-hand operand's reflected dunder depends
-on whether the right-hand operand is an instance of a class that is a subclass of the left-hand
-operand's class and overrides the reflected dunder. In the following example, because of the
-unknowable nature of `Any`/`Unknown`, we must consider both possibilities: `Any`/`Unknown` might
-resolve to an unknown third class that inherits from `X` and overrides `__radd__`; but it also might
-not. Thus, the correct answer here for the `reveal_type` is `int | Unknown`.
+`Any` and `Unknown` represent a set of possible runtime objects, wherein the
+bounds of the set are unknown. Whether the left-hand operand's dunder or the
+right-hand operand's reflected dunder depends on whether the right-hand operand
+is an instance of a class that is a subclass of the left-hand operand's class
+and overrides the reflected dunder. In the following example, because of the
+unknowable nature of `Any`/`Unknown`, we must consider both possibilities:
+`Any`/`Unknown` might resolve to an unknown third class that inherits from `X`
+and overrides `__radd__`; but it also might not. Thus, the correct answer here
+for the `reveal_type` is `int | Unknown`.
 
 ```py
 from does_not_exist import Foo  # error: [unresolved-import]
@@ -415,9 +426,10 @@ reveal_type(B() + C())
 
 ### Reflected dunder is not tried between two objects of the same type
 
-For the specific case where the left-hand operand is the exact same type as the right-hand operand,
-the reflected dunder of the right-hand operand is not tried; the runtime short-circuits after trying
-the unreflected dunder of the left-hand operand. For context, see
+For the specific case where the left-hand operand is the exact same type as the
+right-hand operand, the reflected dunder of the right-hand operand is not
+tried; the runtime short-circuits after trying the unreflected dunder of the
+left-hand operand. For context, see
 [this mailing list discussion](https://mail.python.org/archives/list/python-dev@python.org/thread/7NZUCODEAPQFMRFXYRMGJXDSIS3WJYIV/).
 
 ```py

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

@@ -1,78 +0,0 @@
-# Short-Circuit Evaluation
-
-## Not all boolean expressions must be evaluated
-
-In `or` expressions, if the left-hand side is truthy, the right-hand side is not evaluated.
-Similarly, in `and` expressions, if the left-hand side is falsy, the right-hand side is not
-evaluated.
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance() or (x := 1):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if bool_instance() and (x := 1):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## First expression is always evaluated
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if (x := 1) or bool_instance():
-    reveal_type(x)  # revealed: Literal[1]
-
-if (x := 1) and bool_instance():
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## Statically known truthiness
-
-```py
-if True or (x := 1):
-    # TODO: infer that the second arm is never executed, and raise `unresolved-reference`.
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if True and (x := 1):
-    # TODO: infer that the second arm is always executed, do not raise a diagnostic
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-```
-
-## Later expressions can always use variables from earlier expressions
-
-```py
-def bool_instance() -> bool:
-    return True
-
-bool_instance() or (x := 1) or reveal_type(x)  # revealed: Literal[1]
-
-# error: [unresolved-reference]
-bool_instance() or reveal_type(y) or (y := 1)  # revealed: Unknown
-```
-
-## Nested expressions
-
-```py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance() or ((x := 1) and bool_instance()):
-    # error: [possibly-unresolved-reference]
-    reveal_type(x)  # revealed: Literal[1]
-
-if ((y := 1) and bool_instance()) or bool_instance():
-    reveal_type(y)  # revealed: Literal[1]
-
-# error: [possibly-unresolved-reference]
-if (bool_instance() and (z := 1)) or reveal_type(z):  # revealed: Literal[1]
-    # error: [possibly-unresolved-reference]
-    reveal_type(z)  # revealed: Literal[1]
-```

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

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

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

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

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

@@ -1,7 +1,7 @@
 # Comparison: Byte literals
 
-These tests assert that we infer precise `Literal` types for comparisons between objects inferred as
-having `Literal` bytes types:
+These tests assert that we infer precise `Literal` types for comparisons between objects
+inferred as having `Literal` bytes types:
 
 ```py
 reveal_type(b"abc" == b"abc")  # revealed: Literal[True]

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

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

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

@@ -1,160 +0,0 @@
-# Comparison: Membership Test
-
-In Python, the term "membership test operators" refers to the operators `in` and `not in`. To
-customize their behavior, classes can implement one of the special methods `__contains__`,
-`__iter__`, or `__getitem__`.
-
-For references, see:
-
-- <https://docs.python.org/3/reference/expressions.html#membership-test-details>
-- <https://docs.python.org/3/reference/datamodel.html#object.__contains__>
-- <https://snarky.ca/unravelling-membership-testing/>
-
-## Implements `__contains__`
-
-Classes can support membership tests by implementing the `__contains__` method:
-
-```py
-class A:
-    def __contains__(self, item: str) -> bool:
-        return True
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-# TODO: should emit diagnostic, need to check arg type, will fail
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Implements `__iter__`
-
-Classes that don't implement `__contains__`, but do implement `__iter__`, also support containment
-checks; the needle will be sought in their iterated items:
-
-```py
-class StringIterator:
-    def __next__(self) -> str:
-        return "foo"
-
-class A:
-    def __iter__(self) -> StringIterator:
-        return StringIterator()
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Implements `__getitems__`
-
-The final fallback is to implement `__getitem__` for integer keys. Python will call `__getitem__`
-with `0`, `1`, `2`... until either the needle is found (leading the membership test to evaluate to
-`True`) or `__getitem__` raises `IndexError` (the raised exception is swallowed, but results in the
-membership test evaluating to `False`).
-
-```py
-class A:
-    def __getitem__(self, key: int) -> str:
-        return "foo"
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-reveal_type(42 in A())  # revealed: bool
-reveal_type(42 not in A())  # revealed: bool
-```
-
-## Wrong Return Type
-
-Python coerces the results of containment checks to `bool`, even if `__contains__` returns a
-non-bool:
-
-```py
-class A:
-    def __contains__(self, item: str) -> str:
-        return "foo"
-
-reveal_type("hello" in A())  # revealed: bool
-reveal_type("hello" not in A())  # revealed: bool
-```
-
-## Literal Result for `in` and `not in`
-
-`__contains__` with a literal return type may result in a `BooleanLiteral` outcome.
-
-```py
-from typing import Literal
-
-class AlwaysTrue:
-    def __contains__(self, item: int) -> Literal[1]:
-        return 1
-
-class AlwaysFalse:
-    def __contains__(self, item: int) -> Literal[""]:
-        return ""
-
-reveal_type(42 in AlwaysTrue())  # revealed: Literal[True]
-reveal_type(42 not in AlwaysTrue())  # revealed: Literal[False]
-
-reveal_type(42 in AlwaysFalse())  # revealed: Literal[False]
-reveal_type(42 not in AlwaysFalse())  # revealed: Literal[True]
-```
-
-## No Fallback for `__contains__`
-
-If `__contains__` is implemented, checking membership of a type it doesn't accept is an error; it
-doesn't result in a fallback to `__iter__` or `__getitem__`:
-
-```py
-class CheckContains: ...
-class CheckIter: ...
-class CheckGetItem: ...
-
-class CheckIterIterator:
-    def __next__(self) -> CheckIter:
-        return CheckIter()
-
-class A:
-    def __contains__(self, item: CheckContains) -> bool:
-        return True
-
-    def __iter__(self) -> CheckIterIterator:
-        return CheckIterIterator()
-
-    def __getitem__(self, key: int) -> CheckGetItem:
-        return CheckGetItem()
-
-reveal_type(CheckContains() in A())  # revealed: bool
-
-# TODO: should emit diagnostic, need to check arg type,
-# should not fall back to __iter__ or __getitem__
-reveal_type(CheckIter() in A())  # revealed: bool
-reveal_type(CheckGetItem() in A())  # revealed: bool
-
-class B:
-    def __iter__(self) -> CheckIterIterator:
-        return CheckIterIterator()
-
-    def __getitem__(self, key: int) -> CheckGetItem:
-        return CheckGetItem()
-
-reveal_type(CheckIter() in B())  # revealed: bool
-# Always use `__iter__`, regardless of iterated type; there's no NotImplemented
-# in this case, so there's no fallback to `__getitem__`
-reveal_type(CheckGetItem() in B())  # revealed: bool
-```
-
-## Invalid Old-Style Iteration
-
-If `__getitem__` is implemented but does not accept integer arguments, then the membership test is
-not supported and should trigger a diagnostic.
-
-```py
-class A:
-    def __getitem__(self, key: str) -> str:
-        return "foo"
-
-# TODO should emit a diagnostic
-reveal_type(42 in A())  # revealed: bool
-reveal_type("hello" in A())  # revealed: bool
-```

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

@@ -1,328 +0,0 @@
-# Comparison: Rich Comparison
-
-Rich comparison operations (`==`, `!=`, `<`, `<=`, `>`, `>=`) in Python are implemented through
-double-underscore methods that allow customization of comparison behavior.
-
-For references, see:
-
-- <https://docs.python.org/3/reference/datamodel.html#object.__lt__>
-- <https://snarky.ca/unravelling-rich-comparison-operators/>
-
-## Rich Comparison Dunder Implementations For Same Class
-
-Classes can support rich comparison by implementing dunder methods like `__eq__`, `__ne__`, etc. The
-most common case involves implementing these methods for the same type:
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: A) -> int:
-        return 42
-
-    def __ne__(self, other: A) -> float:
-        return 42.0
-
-    def __lt__(self, other: A) -> str:
-        return "42"
-
-    def __le__(self, other: A) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: A) -> list:
-        return [42]
-
-    def __ge__(self, other: A) -> set:
-        return {42}
-
-reveal_type(A() == A())  # revealed: int
-reveal_type(A() != A())  # revealed: float
-reveal_type(A() < A())  # revealed: str
-reveal_type(A() <= A())  # revealed: bytes
-reveal_type(A() > A())  # revealed: list
-reveal_type(A() >= A())  # revealed: set
-```
-
-## Rich Comparison Dunder Implementations for Other Class
-
-In some cases, classes may implement rich comparison dunder methods for comparisons with a different
-type:
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: B) -> int:
-        return 42
-
-    def __ne__(self, other: B) -> float:
-        return 42.0
-
-    def __lt__(self, other: B) -> str:
-        return "42"
-
-    def __le__(self, other: B) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: B) -> list:
-        return [42]
-
-    def __ge__(self, other: B) -> set:
-        return {42}
-
-class B: ...
-
-reveal_type(A() == B())  # revealed: int
-reveal_type(A() != B())  # revealed: float
-reveal_type(A() < B())  # revealed: str
-reveal_type(A() <= B())  # revealed: bytes
-reveal_type(A() > B())  # revealed: list
-reveal_type(A() >= B())  # revealed: set
-```
-
-## Reflected Comparisons
-
-Fallback to the right-hand side’s comparison methods occurs when the left-hand side does not define
-them. Note: class `B` has its own `__eq__` and `__ne__` methods to override those of `object`, but
-these methods will be ignored here because they require a mismatched operand type.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: B) -> int:
-        return 42
-
-    def __ne__(self, other: B) -> float:
-        return 42.0
-
-    def __lt__(self, other: B) -> str:
-        return "42"
-
-    def __le__(self, other: B) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: B) -> list:
-        return [42]
-
-    def __ge__(self, other: B) -> set:
-        return {42}
-
-class B:
-    # To override builtins.object.__eq__ and builtins.object.__ne__
-    # TODO these should emit an invalid override diagnostic
-    def __eq__(self, other: str) -> B:
-        return B()
-
-    def __ne__(self, other: str) -> B:
-        return B()
-
-# TODO: should be `int` and `float`.
-# Need to check arg type and fall back to `rhs.__eq__` and `rhs.__ne__`.
-#
-# Because `object.__eq__` and `object.__ne__` accept `object` in typeshed,
-# this can only happen with an invalid override of these methods,
-# but we still support it.
-reveal_type(B() == A())  # revealed: B
-reveal_type(B() != A())  # revealed: B
-
-reveal_type(B() < A())  # revealed: list
-reveal_type(B() <= A())  # revealed: set
-
-reveal_type(B() > A())  # revealed: str
-reveal_type(B() >= A())  # revealed: bytes
-
-class C:
-    def __gt__(self, other: C) -> int:
-        return 42
-
-    def __ge__(self, other: C) -> float:
-        return 42.0
-
-reveal_type(C() < C())  # revealed: int
-reveal_type(C() <= C())  # revealed: float
-```
-
-## Reflected Comparisons with Subclasses
-
-When subclasses override comparison methods, these overridden methods take precedence over those in
-the parent class. Class `B` inherits from `A` and redefines comparison methods to return types other
-than `A`.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __eq__(self, other: A) -> A:
-        return A()
-
-    def __ne__(self, other: A) -> A:
-        return A()
-
-    def __lt__(self, other: A) -> A:
-        return A()
-
-    def __le__(self, other: A) -> A:
-        return A()
-
-    def __gt__(self, other: A) -> A:
-        return A()
-
-    def __ge__(self, other: A) -> A:
-        return A()
-
-class B(A):
-    def __eq__(self, other: A) -> int:
-        return 42
-
-    def __ne__(self, other: A) -> float:
-        return 42.0
-
-    def __lt__(self, other: A) -> str:
-        return "42"
-
-    def __le__(self, other: A) -> bytes:
-        return b"42"
-
-    def __gt__(self, other: A) -> list:
-        return [42]
-
-    def __ge__(self, other: A) -> set:
-        return {42}
-
-reveal_type(A() == B())  # revealed: int
-reveal_type(A() != B())  # revealed: float
-
-reveal_type(A() < B())  # revealed: list
-reveal_type(A() <= B())  # revealed: set
-
-reveal_type(A() > B())  # revealed: str
-reveal_type(A() >= B())  # revealed: bytes
-```
-
-## Reflected Comparisons with Subclass But Falls Back to LHS
-
-In the case of a subclass, the right-hand side has priority. However, if the overridden dunder
-method has an mismatched type to operand, the comparison will fall back to the left-hand side.
-
-```py
-from __future__ import annotations
-
-class A:
-    def __lt__(self, other: A) -> A:
-        return A()
-
-    def __gt__(self, other: A) -> A:
-        return A()
-
-class B(A):
-    def __lt__(self, other: int) -> B:
-        return B()
-
-    def __gt__(self, other: int) -> B:
-        return B()
-
-# TODO: should be `A`, need to check argument type and fall back to LHS method
-reveal_type(A() < B())  # revealed: B
-reveal_type(A() > B())  # revealed: B
-```
-
-## Operations involving instances of classes inheriting from `Any`
-
-`Any` and `Unknown` represent a set of possible runtime objects, wherein the bounds of the set are
-unknown. Whether the left-hand operand's dunder or the right-hand operand's reflected dunder depends
-on whether the right-hand operand is an instance of a class that is a subclass of the left-hand
-operand's class and overrides the reflected dunder. In the following example, because of the
-unknowable nature of `Any`/`Unknown`, we must consider both possibilities: `Any`/`Unknown` might
-resolve to an unknown third class that inherits from `X` and overrides `__gt__`; but it also might
-not. Thus, the correct answer here for the `reveal_type` is `int | Unknown`.
-
-(This test is referenced from `mdtest/binary/instances.md`)
-
-```py
-from does_not_exist import Foo  # error: [unresolved-import]
-
-reveal_type(Foo)  # revealed: Unknown
-
-class X:
-    def __lt__(self, other: object) -> int:
-        return 42
-
-class Y(Foo): ...
-
-# TODO: Should be `int | Unknown`; see above discussion.
-reveal_type(X() < Y())  # revealed: int
-```
-
-## Equality and Inequality Fallback
-
-This test confirms that `==` and `!=` comparisons default to identity comparisons (`is`, `is not`)
-when argument types do not match the method signature.
-
-Please refer to the [docs](https://docs.python.org/3/reference/datamodel.html#object.__eq__)
-
-```py
-from __future__ import annotations
-
-class A:
-    # TODO both these overrides should emit invalid-override diagnostic
-    def __eq__(self, other: int) -> A:
-        return A()
-
-    def __ne__(self, other: int) -> A:
-        return A()
-
-# TODO: it should be `bool`, need to check arg type and fall back to `is` and `is not`
-reveal_type(A() == A())  # revealed: A
-reveal_type(A() != A())  # revealed: A
-```
-
-## Object Comparisons with Typeshed
-
-```py
-class A: ...
-
-reveal_type(A() == object())  # revealed: bool
-reveal_type(A() != object())  # revealed: bool
-reveal_type(object() == A())  # revealed: bool
-reveal_type(object() != A())  # revealed: bool
-
-# error: [unsupported-operator] "Operator `<` is not supported for types `A` and `object`"
-# revealed: Unknown
-reveal_type(A() < object())
-```
-
-## Numbers Comparison with typeshed
-
-```py
-reveal_type(1 == 1.0)  # revealed: bool
-reveal_type(1 != 1.0)  # revealed: bool
-reveal_type(1 < 1.0)  # revealed: bool
-reveal_type(1 <= 1.0)  # revealed: bool
-reveal_type(1 > 1.0)  # revealed: bool
-reveal_type(1 >= 1.0)  # revealed: bool
-
-reveal_type(1 == 2j)  # revealed: bool
-reveal_type(1 != 2j)  # revealed: bool
-
-# TODO: should be Unknown and emit diagnostic,
-# need to check arg type and should be failed
-reveal_type(1 < 2j)  # revealed: bool
-reveal_type(1 <= 2j)  # revealed: bool
-reveal_type(1 > 2j)  # revealed: bool
-reveal_type(1 >= 2j)  # revealed: bool
-
-def bool_instance() -> bool:
-    return True
-
-def int_instance() -> int:
-    return 42
-
-x = bool_instance()
-y = int_instance()
-
-reveal_type(x < y)  # revealed: bool
-reveal_type(y < x)  # revealed: bool
-reveal_type(4.2 < x)  # revealed: bool
-reveal_type(x < 4.2)  # revealed: bool
-```

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

@@ -12,18 +12,16 @@ reveal_type(1 is 1)  # revealed: bool
 reveal_type(1 is not 1)  # revealed: bool
 reveal_type(1 is 2)  # revealed: Literal[False]
 reveal_type(1 is not 7)  # revealed: Literal[True]
-# TODO: should be Unknown, and emit diagnostic, once we check call argument types
-reveal_type(1 <= "" and 0 < 1)  # revealed: bool
+reveal_type(1 <= "" and 0 < 1)  # revealed: @Todo | Literal[True]
 ```
 
 ## Integer instance
 
 ```py
 # TODO: implement lookup of `__eq__` on typeshed `int` stub.
-def int_instance() -> int:
-    return 42
+def int_instance() -> int: ...
 
-reveal_type(1 == int_instance())  # revealed: bool
+reveal_type(1 == int_instance())  # revealed: @Todo
 reveal_type(9 < int_instance())  # revealed: bool
 reveal_type(int_instance() < int_instance())  # revealed: bool
 ```

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

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

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

@@ -5,9 +5,9 @@ Walking through examples:
 - `a = A() < B() < C()`
 
     1. `A() < B() and B() < C()` - split in N comparison
-    1. `A()` and `B()` - evaluate outcome types
-    1. `bool` and `bool` - evaluate truthiness
-    1. `A | B` - union of "first true" types
+    1. `A()` and `B()`              - evaluate outcome types
+    1. `bool` and `bool`            - evaluate truthiness
+    1. `A | B`                    - union of "first true" types
 
 - `b = 0 < 1 < A() < 3`
 

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

@@ -59,51 +59,51 @@ reveal_type(c >= d)  # revealed: Literal[True]
 
 ```py
 def bool_instance() -> bool: ...
-def int_instance() -> int:
-    return 42
+def int_instance() -> int: ...
 
 a = (bool_instance(),)
 b = (int_instance(),)
 
-reveal_type(a == a)  # revealed: bool
-reveal_type(a != a)  # revealed: bool
-reveal_type(a < a)  # revealed: bool
-reveal_type(a <= a)  # revealed: bool
-reveal_type(a > a)  # revealed: bool
-reveal_type(a >= a)  # revealed: bool
+# TODO: All @Todo should be `bool`
+reveal_type(a == a)  # revealed: @Todo
+reveal_type(a != a)  # revealed: @Todo
+reveal_type(a < a)  # revealed: @Todo
+reveal_type(a <= a)  # revealed: @Todo
+reveal_type(a > a)  # revealed: @Todo
+reveal_type(a >= a)  # revealed: @Todo
 
-reveal_type(a == b)  # revealed: bool
-reveal_type(a != b)  # revealed: bool
-reveal_type(a < b)  # revealed: bool
-reveal_type(a <= b)  # revealed: bool
-reveal_type(a > b)  # revealed: bool
-reveal_type(a >= b)  # revealed: bool
+reveal_type(a == b)  # revealed: @Todo
+reveal_type(a != b)  # revealed: @Todo
+reveal_type(a < b)  # revealed: @Todo
+reveal_type(a <= b)  # revealed: @Todo
+reveal_type(a > b)  # revealed: @Todo
+reveal_type(a >= b)  # revealed: @Todo
 ```
 
 #### Comparison Unsupported
 
-If two tuples contain types that do not support comparison, the result may be `Unknown`. However,
-`==` and `!=` are exceptions and can still provide definite results.
+If two tuples contain types that do not support comparison, the result may be `Unknown`.
+However, `==` and `!=` are exceptions and can still provide definite results.
 
 ```py
 a = (1, 2)
 b = (1, "hello")
 
-# TODO: should be Literal[False], once we implement (in)equality for mismatched literals
-reveal_type(a == b)  # revealed: bool
+# TODO: should be Literal[False]
+reveal_type(a == b)  # revealed: @Todo
 
-# TODO: should be Literal[True], once we implement (in)equality for mismatched literals
-reveal_type(a != b)  # revealed: bool
+# TODO: should be Literal[True]
+reveal_type(a != b)  # revealed: @Todo
 
 # TODO: should be Unknown and add more informative diagnostics
-reveal_type(a < b)  # revealed: bool
-reveal_type(a <= b)  # revealed: bool
-reveal_type(a > b)  # revealed: bool
-reveal_type(a >= b)  # revealed: bool
+reveal_type(a < b)  # revealed: @Todo
+reveal_type(a <= b)  # revealed: @Todo
+reveal_type(a > b)  # revealed: @Todo
+reveal_type(a >= b)  # revealed: @Todo
 ```
 
-However, if the lexicographic comparison completes without reaching a point where str and int are
-compared, Python will still produce a result based on the prior elements.
+However, if the lexicographic comparison completes without reaching a point where str and int are compared,
+Python will still produce a result based on the prior elements.
 
 ```py path=short_circuit.py
 a = (1, 2)
@@ -145,12 +145,13 @@ class A:
 
 a = (A(), A())
 
-reveal_type(a == a)  # revealed: bool
-reveal_type(a != a)  # revealed: bool
-reveal_type(a < a)  # revealed: bool
-reveal_type(a <= a)  # revealed: bool
-reveal_type(a > a)  # revealed: bool
-reveal_type(a >= a)  # revealed: bool
+# TODO: All @Todo should be bool
+reveal_type(a == a)  # revealed: @Todo
+reveal_type(a != a)  # revealed: @Todo
+reveal_type(a < a)  # revealed: @Todo
+reveal_type(a <= a)  # revealed: @Todo
+reveal_type(a > a)  # revealed: @Todo
+reveal_type(a >= a)  # revealed: @Todo
 ```
 
 ### Membership Test Comparisons
@@ -158,8 +159,7 @@ reveal_type(a >= a)  # revealed: bool
 "Membership Test Comparisons" refers to the operators `in` and `not in`.
 
 ```py
-def int_instance() -> int:
-    return 42
+def int_instance() -> int: ...
 
 a = (1, 2)
 b = ((3, 4), (1, 2))
@@ -172,8 +172,9 @@ reveal_type(a not in b)  # revealed: Literal[False]
 reveal_type(a in c)  # revealed: Literal[False]
 reveal_type(a not in c)  # revealed: Literal[True]
 
-reveal_type(a in d)  # revealed: bool
-reveal_type(a not in d)  # revealed: bool
+# TODO: All @Todo should be bool
+reveal_type(a in d)  # revealed: @Todo
+reveal_type(a not in d)  # revealed: @Todo
 ```
 
 ### Identity Comparisons
@@ -188,10 +189,10 @@ c = (1, 2, 3)
 reveal_type(a is (1, 2))  # revealed: bool
 reveal_type(a is not (1, 2))  # revealed: bool
 
-# TODO should be Literal[False] once we implement comparison of mismatched literal types
-reveal_type(a is b)  # revealed: bool
-# TODO should be Literal[True] once we implement comparison of mismatched literal types
-reveal_type(a is not b)  # revealed: bool
+# TODO: Update to Literal[False] once str == int comparison is implemented
+reveal_type(a is b)  # revealed: @Todo
+# TODO: Update to Literal[True] once str == int comparison is implemented
+reveal_type(a is not b)  # revealed: @Todo
 
 reveal_type(a is c)  # revealed: Literal[False]
 reveal_type(a is not c)  # revealed: Literal[True]

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

@@ -52,8 +52,8 @@ reveal_type(one_or_none is not None)  # revealed: bool
 
 ## Union on both sides of the comparison
 
-With unions on both sides, we need to consider the full cross product of options when building the
-resulting (union) type:
+With unions on both sides, we need to consider the full cross product of
+options when building the resulting (union) type:
 
 ```py
 def bool_instance() -> bool:
@@ -72,9 +72,9 @@ reveal_type(small > large)  # revealed: Literal[False]
 
 ## Unsupported operations
 
-Make sure we emit a diagnostic if *any* of the possible comparisons is unsupported. For now, we fall
-back to `bool` for the result type instead of trying to infer something more precise from the other
-(supported) variants:
+Make sure we emit a diagnostic if *any* of the possible comparisons is
+unsupported. For now, we fall back to `bool` for the result type instead of
+trying to infer something more precise from the other (supported) variants:
 
 ```py
 def bool_instance() -> bool:

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

@@ -10,16 +10,12 @@ reveal_type(a)  # revealed: bool
 b = 0 not in 10  # error: "Operator `not in` is not supported for types `Literal[0]` and `Literal[10]`"
 reveal_type(b)  # revealed: bool
 
-# TODO: should error, once operand type check is implemented
-# ("Operator `<` is not supported for types `object` and `int`")
-c = object() < 5
-# TODO: should be Unknown, once operand type check is implemented
-reveal_type(c)  # revealed: bool
+c = object() < 5  # error: "Operator `<` is not supported for types `object` and `int`"
+reveal_type(c)  # revealed: Unknown
 
-# TODO: should error, once operand type check is implemented
-# ("Operator `<` is not supported for types `int` and `object`")
+# TODO should error, need to check if __lt__ signature is valid for right operand
 d = 5 < object()
-# TODO: should be Unknown, once operand type check is implemented
+# TODO: should be `Unknown`
 reveal_type(d)  # revealed: bool
 
 flag = bool_instance()
@@ -31,6 +27,5 @@ reveal_type(e)  # revealed: bool
 # TODO: should error, need to check if __lt__ signature is valid for right operand
 # error may be "Operator `<` is not supported for types `int` and `str`, in comparing `tuple[Literal[1], Literal[2]]` with `tuple[Literal[1], Literal["hello"]]`
 f = (1, 2) < (1, "hello")
-# TODO: should be Unknown, once operand type check is implemented
-reveal_type(f)  # revealed: bool
+reveal_type(f)  # revealed: @Todo
 ```

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

@@ -37,11 +37,11 @@ x = y
 
 reveal_type(x)  # revealed: Literal[3, 4, 5]
 
-# revealed: Literal[2]
+# revealed: Unbound | Literal[2]
 # error: [possibly-unresolved-reference]
 reveal_type(r)
 
-# revealed: Literal[5]
+# revealed: Unbound | Literal[5]
 # error: [possibly-unresolved-reference]
 reveal_type(s)
 ```

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

@@ -21,7 +21,7 @@ match 0:
     case 2:
         y = 3
 
-# revealed: Literal[2, 3]
+# revealed: Unbound | Literal[2, 3]
 # error: [possibly-unresolved-reference]
 reveal_type(y)
 ```

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

@@ -41,12 +41,7 @@ except EXCEPTIONS as f:
 ## Dynamic exception types
 
 ```py
-# TODO: we should not emit these `call-possibly-unbound-method` errors for `tuple.__class_getitem__`
-def foo(
-    x: type[AttributeError],
-    y: tuple[type[OSError], type[RuntimeError]],  # error: [call-possibly-unbound-method]
-    z: tuple[type[BaseException], ...],  # error: [call-possibly-unbound-method]
-):
+def foo(x: type[AttributeError], y: tuple[type[OSError], type[RuntimeError]], z: tuple[type[BaseException], ...]):
     try:
         help()
     except x as e:

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

@@ -1,33 +1,40 @@
 # Control flow for exception handlers
 
-These tests assert that we understand the possible "definition states" (which symbols might or might
-not be defined) in the various branches of a `try`/`except`/`else`/`finally` block.
+These tests assert that we understand the possible "definition states" (which
+symbols might or might not be defined) in the various branches of a
+`try`/`except`/`else`/`finally` block.
 
-For a full writeup on the semantics of exception handlers, see [this document][1].
+For a full writeup on the semantics of exception handlers,
+see [this document][1].
 
-The tests throughout this Markdown document use functions with names starting with `could_raise_*`
-to mark definitions that might or might not succeed (as the function could raise an exception). A
-type checker must assume that any arbitrary function call could raise an exception in Python; this
-is just a naming convention used in these tests for clarity, and to future-proof the tests against
-possible future improvements whereby certain statements or expressions could potentially be inferred
-as being incapable of causing an exception to be raised.
+The tests throughout this Markdown document use functions with names starting
+with `could_raise_*` to mark definitions that might or might not succeed
+(as the function could raise an exception). A type checker must assume that any
+arbitrary function call could raise an exception in Python; this is just a
+naming convention used in these tests for clarity, and to future-proof the
+tests against possible future improvements whereby certain statements or
+expressions could potentially be inferred as being incapable of causing an
+exception to be raised.
 
 ## A single bare `except`
 
-Consider the following `try`/`except` block, with a single bare `except:`. There are different types
-for the variable `x` in the two branches of this block, and we can't determine which branch might
-have been taken from the perspective of code following this block. The inferred type after the
-block's conclusion is therefore the union of the type at the end of the `try` suite (`str`) and the
-type at the end of the `except` suite (`Literal[2]`).
+Consider the following `try`/`except` block, with a single bare `except:`.
+There are different types for the variable `x` in the two branches of this
+block, and we can't determine which branch might have been taken from the
+perspective of code following this block. The inferred type after the block's
+conclusion is therefore the union of the type at the end of the `try` suite
+(`str`) and the type at the end of the `except` suite (`Literal[2]`).
 
-*Within* the `except` suite, we must infer a union of all possible "definition states" we could have
-been in at any point during the `try` suite. This is because control flow could have jumped to the
-`except` suite without any of the `try`-suite definitions successfully completing, with only *some*
-of the `try`-suite definitions successfully completing, or indeed with *all* of them successfully
-completing. The type of `x` at the beginning of the `except` suite in this example is therefore
-`Literal[1] | str`, taking into account that we might have jumped to the `except` suite before the
-`x = could_raise_returns_str()` redefinition, but we *also* could have jumped to the `except` suite
-*after* that redefinition.
+*Within* the `except` suite, we must infer a union of all possible "definition
+states" we could have been in at any point during the `try` suite. This is
+because control flow could have jumped to the `except` suite without any of the
+`try`-suite definitions successfully completing, with only *some* of the
+`try`-suite definitions successfully completing, or indeed with *all* of them
+successfully completing. The type of `x` at the beginning of the `except` suite
+in this example is therefore `Literal[1] | str`, taking into account that we
+might have jumped to the `except` suite before the
+`x = could_raise_returns_str()` redefinition, but we *also* could have jumped
+to the `except` suite *after* that redefinition.
 
 ```py path=union_type_inferred.py
 def could_raise_returns_str() -> str:
@@ -47,8 +54,9 @@ except:
 reveal_type(x)  # revealed: str | Literal[2]
 ```
 
-If `x` has the same type at the end of both branches, however, the branches unify and `x` is not
-inferred as having a union type following the `try`/`except` block:
+If `x` has the same type at the end of both branches, however, the branches
+unify and `x` is not inferred as having a union type following the
+`try`/`except` block:
 
 ```py path=branches_unify_to_non_union_type.py
 def could_raise_returns_str() -> str:
@@ -66,12 +74,13 @@ reveal_type(x)  # revealed: str
 
 ## A non-bare `except`
 
-For simple `try`/`except` blocks, an `except TypeError:` handler has the same control flow semantics
-as an `except:` handler. An `except TypeError:` handler will not catch *all* exceptions: if this is
-the only handler, it opens up the possibility that an exception might occur that would not be
-handled. However, as described in [the document on exception-handling semantics][1], that would lead
-to termination of the scope. It's therefore irrelevant to consider this possibility when it comes to
-control-flow analysis.
+For simple `try`/`except` blocks, an `except TypeError:` handler has the same
+control flow semantics as an `except:` handler. An `except TypeError:` handler
+will not catch *all* exceptions: if this is the only handler, it opens up the
+possibility that an exception might occur that would not be handled. However,
+as described in [the document on exception-handling semantics][1], that would
+lead to termination of the scope. It's therefore irrelevant to consider this
+possibility when it comes to control-flow analysis.
 
 ```py
 def could_raise_returns_str() -> str:
@@ -93,9 +102,11 @@ reveal_type(x)  # revealed: str | Literal[2]
 
 ## Multiple `except` branches
 
-If the scope reaches the final `reveal_type` call in this example, either the `try`-block suite of
-statements was executed in its entirety, or exactly one `except` suite was executed in its entirety.
-The inferred type of `x` at this point is the union of the types at the end of the three suites:
+If the scope reaches the final `reveal_type` call in this example,
+either the `try`-block suite of statements was executed in its entirety,
+or exactly one `except` suite was executed in its entirety.
+The inferred type of `x` at this point is the union of the types at the end of
+the three suites:
 
 - At the end of `try`, `type(x) == str`
 - At the end of `except TypeError`, `x == 2`
@@ -125,10 +136,11 @@ reveal_type(x)  # revealed: str | Literal[2, 3]
 
 ## Exception handlers with `else` branches (but no `finally`)
 
-If we reach the `reveal_type` call at the end of this scope, either the `try` and `else` suites were
-both executed in their entireties, or the `except` suite was executed in its entirety. The type of
-`x` at this point is the union of the type at the end of the `else` suite and the type at the end of
-the `except` suite:
+If we reach the `reveal_type` call at the end of this scope,
+either the `try` and `else` suites were both executed in their entireties,
+or the `except` suite was executed in its entirety. The type of `x` at this
+point is the union of the type at the end of the `else` suite and the type at
+the end of the `except` suite:
 
 - At the end of `else`, `x == 3`
 - At the end of `except`, `x == 2`
@@ -155,9 +167,10 @@ else:
 reveal_type(x)  # revealed: Literal[2, 3]
 ```
 
-For a block that has multiple `except` branches and an `else` branch, the same principle applies. In
-order to reach the final `reveal_type` call, either exactly one of the `except` suites must have
-been executed in its entirety, or the `try` suite and the `else` suite must both have been executed
+For a block that has multiple `except` branches and an `else` branch, the same
+principle applies. In order to reach the final `reveal_type` call,
+either exactly one of the `except` suites must have been executed in its
+entirety, or the `try` suite and the `else` suite must both have been executed
 in their entireties:
 
 ```py
@@ -188,9 +201,10 @@ reveal_type(x)  # revealed: Literal[2, 3, 4]
 
 ## Exception handlers with `finally` branches (but no `except` branches)
 
-A `finally` suite is *always* executed. As such, if we reach the `reveal_type` call at the end of
-this example, we know that `x` *must* have been reassigned to `2` during the `finally` suite. The
-type of `x` at the end of the example is therefore `Literal[2]`:
+A `finally` suite is *always* executed. As such, if we reach the `reveal_type`
+call at the end of this example, we know that `x` *must* have been reassigned
+to `2` during the `finally` suite. The type of `x` at the end of the example is
+therefore `Literal[2]`:
 
 ```py path=redef_in_finally.py
 def could_raise_returns_str() -> str:
@@ -209,13 +223,15 @@ finally:
 reveal_type(x)  # revealed: Literal[2]
 ```
 
-If `x` was *not* redefined in the `finally` suite, however, things are somewhat more complicated. If
-we reach the final `reveal_type` call, unlike the state when we're visiting the `finally` suite, we
-know that the `try`-block suite ran to completion. This means that there are fewer possible states
-at this point than there were when we were inside the `finally` block.
+If `x` was *not* redefined in the `finally` suite, however, things are somewhat
+more complicated. If we reach the final `reveal_type` call,
+unlike the state when we're visiting the `finally` suite,
+we know that the `try`-block suite ran to completion.
+This means that there are fewer possible states at this point than there were
+when we were inside the `finally` block.
 
-(Our current model does *not* correctly infer the types *inside* `finally` suites, however; this is
-still a TODO item for us.)
+(Our current model does *not* correctly infer the types *inside* `finally`
+suites, however; this is still a TODO item for us.)
 
 ```py path=no_redef_in_finally.py
 def could_raise_returns_str() -> str:
@@ -236,18 +252,18 @@ reveal_type(x)  # revealed: str
 
 ## Combining an `except` branch with a `finally` branch
 
-As previously stated, we do not yet have accurate inference for types *inside* `finally` suites.
-When we do, however, we will have to take account of the following possibilities inside `finally`
-suites:
+As previously stated, we do not yet have accurate inference for types *inside*
+`finally` suites. When we do, however, we will have to take account of the
+following possibilities inside `finally` suites:
 
 - The `try` suite could have run to completion
-- Or we could have jumped from halfway through the `try` suite to an `except` suite, and the
-    `except` suite ran to completion
-- Or we could have jumped from halfway through the `try` suite straight to the `finally` suite due
-    to an unhandled exception
-- Or we could have jumped from halfway through the `try` suite to an `except` suite, only for an
-    exception raised in the `except` suite to cause us to jump to the `finally` suite before the
-    `except` suite ran to completion
+- Or we could have jumped from halfway through the `try` suite to an `except`
+    suite, and the `except` suite ran to completion
+- Or we could have jumped from halfway through the `try` suite straight to the
+    `finally` suite due to an unhandled exception
+- Or we could have jumped from halfway through the `try` suite to an
+    `except` suite, only for an exception raised in the `except` suite to cause
+    us to jump to the `finally` suite before the `except` suite ran to completion
 
 ```py path=redef_in_finally.py
 def could_raise_returns_str() -> str:
@@ -280,11 +296,12 @@ finally:
 reveal_type(x)  # revealed: Literal[2]
 ```
 
-Now for an example without a redefinition in the `finally` suite. As before, there *should* be fewer
-possibilities after completion of the `finally` suite than there were during the `finally` suite
-itself. (In some control-flow possibilities, some exceptions were merely *suspended* during the
-`finally` suite; these lead to the scope's termination following the conclusion of the `finally`
-suite.)
+Now for an example without a redefinition in the `finally` suite.
+As before, there *should* be fewer possibilities after completion of the
+`finally` suite than there were during the `finally` suite itself.
+(In some control-flow possibilities, some exceptions were merely *suspended*
+during the `finally` suite; these lead to the scope's termination following the
+conclusion of the `finally` suite.)
 
 ```py path=no_redef_in_finally.py
 def could_raise_returns_str() -> str:
@@ -360,9 +377,9 @@ reveal_type(x)  # revealed: str | bool | float
 
 ## Combining `except`, `else` and `finally` branches
 
-If the exception handler has an `else` branch, we must also take into account the possibility that
-control flow could have jumped to the `finally` suite from partway through the `else` suite due to
-an exception raised *there*.
+If the exception handler has an `else` branch, we must also take into account
+the possibility that control flow could have jumped to the `finally` suite from
+partway through the `else` suite due to an exception raised *there*.
 
 ```py path=single_except_branch.py
 def could_raise_returns_str() -> str:
@@ -462,13 +479,15 @@ reveal_type(x)  # revealed: bool | float | slice
 
 ## Nested `try`/`except` blocks
 
-It would take advanced analysis, which we are not yet capable of, to be able to determine that an
-exception handler always suppresses all exceptions. This is partly because it is possible for
-statements in `except`, `else` and `finally` suites to raise exceptions as well as statements in
-`try` suites. This means that if an exception handler is nested inside the `try` statement of an
-enclosing exception handler, it should (at least for now) be treated the same as any other node: as
-a suite containing statements that could possibly raise exceptions, which would lead to control flow
-jumping out of that suite prior to the suite running to completion.
+It would take advanced analysis, which we are not yet capable of, to be able
+to determine that an exception handler always suppresses all exceptions. This
+is partly because it is possible for statements in `except`, `else` and
+`finally` suites to raise exceptions as well as statements in `try` suites.
+This means that if an exception handler is nested inside the `try` statement of
+an enclosing exception handler, it should (at least for now) be treated the
+same as any other node: as a suite containing statements that could possibly
+raise exceptions, which would lead to control flow jumping out of that suite
+prior to the suite running to completion.
 
 ```py
 def could_raise_returns_str() -> str:
@@ -561,8 +580,8 @@ reveal_type(x)  # revealed: bytearray | Bar
 
 ## Nested scopes inside `try` blocks
 
-Shadowing a variable in an inner scope has no effect on type inference of the variable by that name
-in the outer scope:
+Shadowing a variable in an inner scope has no effect on type inference of the
+variable by that name in the outer scope:
 
 ```py
 def could_raise_returns_str() -> str:

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

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

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

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

crates/red_knot_python_semantic/resources/mdtest/generics.md

@@ -16,11 +16,10 @@ class MyBox[T]:
     def __init__(self, data: T):
         self.data = data
 
-box: MyBox[int] = MyBox(5)
-
-# TODO should emit a diagnostic here (str is not assignable to int)
-wrong_innards: MyBox[int] = MyBox("five")
-
+# TODO not error (should be subscriptable)
+box: MyBox[int] = MyBox(5)  # error: [non-subscriptable]
+# TODO error differently (str and int don't unify)
+wrong_innards: MyBox[int] = MyBox("five")  # error: [non-subscriptable]
 # TODO reveal int
 reveal_type(box.data)  # revealed: @Todo
 
@@ -53,8 +52,7 @@ reveal_type(secure_box.data)  # revealed: @Todo
 
 ## Cyclical class definition
 
-In type stubs, classes can reference themselves in their base class definitions. For example, in
-`typeshed`, we have `class str(Sequence[str]): ...`.
+In type stubs, classes can reference themselves in their base class definitions. For example, in `typeshed`, we have `class str(Sequence[str]): ...`.
 
 This should hold true even with generics at play.
 

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

@@ -12,10 +12,11 @@ if flag:
 
 x = y  # error: [possibly-unresolved-reference]
 
-# revealed: Literal[3]
+# revealed: Unbound | Literal[3]
+# error: [possibly-unresolved-reference]
 reveal_type(x)
 
-# revealed: Literal[3]
+# revealed: Unbound | Literal[3]
 # error: [possibly-unresolved-reference]
 reveal_type(y)
 ```
@@ -39,10 +40,11 @@ if flag:
     y: int = 3
 x = y  # error: [possibly-unresolved-reference]
 
-# revealed: Literal[3]
+# revealed: Unbound | Literal[3]
+# error: [possibly-unresolved-reference]
 reveal_type(x)
 
-# revealed: Literal[3]
+# revealed: Unbound | Literal[3]
 # error: [possibly-unresolved-reference]
 reveal_type(y)
 ```
@@ -56,24 +58,6 @@ reveal_type(x)  # revealed: Literal[3]
 reveal_type(y)  # revealed: int
 ```
 
-## Maybe undeclared
-
-Importing a possibly undeclared name still gives us its declared type:
-
-```py path=maybe_undeclared.py
-def bool_instance() -> bool:
-    return True
-
-if bool_instance():
-    x: int
-```
-
-```py
-from maybe_undeclared import x
-
-reveal_type(x)  # revealed: int
-```
-
 ## Reimport
 
 ```py path=c.py

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

@@ -1,91 +0,0 @@
-# Literal
-
-<https://typing.readthedocs.io/en/latest/spec/literal.html#literals>
-
-## Parameterization
-
-```py
-from typing import Literal
-from enum import Enum
-
-mode: Literal["w", "r"]
-mode2: Literal["w"] | Literal["r"]
-union_var: Literal[Literal[Literal[1, 2, 3], "foo"], 5, None]
-a1: Literal[26]
-a2: Literal[0x1A]
-a3: Literal[-4]
-a4: Literal["hello world"]
-a5: Literal[b"hello world"]
-a6: Literal[True]
-a7: Literal[None]
-a8: Literal[Literal[1]]
-a9: Literal[Literal["w"], Literal["r"], Literal[Literal["w+"]]]
-
-class Color(Enum):
-    RED = 0
-    GREEN = 1
-    BLUE = 2
-
-b1: Literal[Color.RED]
-
-def f():
-    reveal_type(mode)  # revealed: Literal["w", "r"]
-    reveal_type(mode2)  # revealed: Literal["w", "r"]
-    # TODO: should be revealed: Literal[1, 2, 3, "foo", 5] | None
-    reveal_type(union_var)  # revealed: Literal[1, 2, 3, 5] | Literal["foo"] | None
-    reveal_type(a1)  # revealed: Literal[26]
-    reveal_type(a2)  # revealed: Literal[26]
-    reveal_type(a3)  # revealed: Literal[-4]
-    reveal_type(a4)  # revealed: Literal["hello world"]
-    reveal_type(a5)  # revealed: Literal[b"hello world"]
-    reveal_type(a6)  # revealed: Literal[True]
-    reveal_type(a7)  # revealed: None
-    reveal_type(a8)  # revealed: Literal[1]
-    reveal_type(a9)  # revealed: Literal["w", "r", "w+"]
-    # TODO: This should be Color.RED
-    reveal_type(b1)  # revealed: Literal[0]
-
-# error: [invalid-literal-parameter]
-invalid1: Literal[3 + 4]
-# error: [invalid-literal-parameter]
-invalid2: Literal[4 + 3j]
-# error: [invalid-literal-parameter]
-invalid3: Literal[(3, 4)]
-invalid4: Literal[
-    1 + 2,  # error: [invalid-literal-parameter]
-    "foo",
-    hello,  # error: [invalid-literal-parameter]
-    (1, 2, 3),  # error: [invalid-literal-parameter]
-]
-```
-
-## Detecting Literal outside typing and typing_extensions
-
-Only Literal that is defined in typing and typing_extension modules is detected as the special
-Literal.
-
-```pyi path=other.pyi
-from typing import _SpecialForm
-
-Literal: _SpecialForm
-```
-
-```py
-from other import Literal
-
-a1: Literal[26]
-
-def f():
-    reveal_type(a1)  # revealed: @Todo
-```
-
-## Detecting typing_extensions.Literal
-
-```py
-from typing_extensions import Literal
-
-a1: Literal[26]
-
-def f():
-    reveal_type(a1)  # revealed: Literal[26]
-```

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

@@ -17,8 +17,8 @@ async def foo():
     async for x in Iterator():
         pass
 
-    # TODO: should reveal `Unknown` because `__aiter__` is not defined
-    # revealed: @Todo
+    # TODO: should reveal `Unbound | Unknown` because `__aiter__` is not defined
+    # revealed: Unbound | @Todo
     # error: [possibly-unresolved-reference]
     reveal_type(x)
 ```
@@ -40,6 +40,6 @@ async def foo():
         pass
 
     # error: [possibly-unresolved-reference]
-    # revealed: @Todo
+    # revealed: Unbound | @Todo
     reveal_type(x)
 ```

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

@@ -14,7 +14,7 @@ class IntIterable:
 for x in IntIterable():
     pass
 
-# revealed: int
+# revealed: Unbound | int
 # error: [possibly-unresolved-reference]
 reveal_type(x)
 ```
@@ -87,7 +87,7 @@ class OldStyleIterable:
 for x in OldStyleIterable():
     pass
 
-# revealed: int
+# revealed: Unbound | int
 # error: [possibly-unresolved-reference]
 reveal_type(x)
 ```
@@ -98,7 +98,7 @@ reveal_type(x)
 for x in (1, "a", b"foo"):
     pass
 
-# revealed: Literal[1] | Literal["a"] | Literal[b"foo"]
+# revealed: Unbound | Literal[1] | Literal["a"] | Literal[b"foo"]
 # error: [possibly-unresolved-reference]
 reveal_type(x)
 ```
@@ -120,7 +120,7 @@ class NotIterable:
 for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
     pass
 
-# revealed: Unknown
+# revealed: Unbound | Unknown
 # error: [possibly-unresolved-reference]
 reveal_type(x)
 ```
@@ -144,140 +144,3 @@ class NotIterable:
 for x in NotIterable():  # error: "Object of type `NotIterable` is not iterable"
     pass
 ```
-
-## Union type as iterable
-
-```py
-class TestIter:
-    def __next__(self) -> int:
-        return 42
-
-class Test:
-    def __iter__(self) -> TestIter:
-        return TestIter()
-
-class Test2:
-    def __iter__(self) -> TestIter:
-        return TestIter()
-
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-for x in Test() if flag else Test2():
-    reveal_type(x)  # revealed: int
-```
-
-## Union type as iterator
-
-```py
-class TestIter:
-    def __next__(self) -> int:
-        return 42
-
-class TestIter2:
-    def __next__(self) -> int:
-        return 42
-
-class Test:
-    def __iter__(self) -> TestIter | TestIter2:
-        return TestIter()
-
-for x in Test():
-    reveal_type(x)  # revealed: int
-```
-
-## Union type as iterable and union type as iterator
-
-```py
-class TestIter:
-    def __next__(self) -> int | Exception:
-        return 42
-
-class TestIter2:
-    def __next__(self) -> str | tuple[int, int]:
-        return "42"
-
-class TestIter3:
-    def __next__(self) -> bytes:
-        return b"42"
-
-class TestIter4:
-    def __next__(self) -> memoryview:
-        return memoryview(b"42")
-
-class Test:
-    def __iter__(self) -> TestIter | TestIter2:
-        return TestIter()
-
-class Test2:
-    def __iter__(self) -> TestIter3 | TestIter4:
-        return TestIter3()
-
-def bool_instance() -> bool:
-    return True
-
-flag = bool_instance()
-
-for x in Test() if flag else Test2():
-    reveal_type(x)  # revealed: int | Exception | str | tuple[int, int] | bytes | memoryview
-```
-
-## Union type as iterable where one union element has no `__iter__` method
-
-```py
-class TestIter:
-    def __next__(self) -> int:
-        return 42
-
-class Test:
-    def __iter__(self) -> TestIter:
-        return TestIter()
-
-def coinflip() -> bool:
-    return True
-
-# error: [not-iterable] "Object of type `Test | Literal[42]` is not iterable because its `__iter__` method is possibly unbound"
-for x in Test() if coinflip() else 42:
-    reveal_type(x)  # revealed: int
-```
-
-## Union type as iterable where one union element has invalid `__iter__` method
-
-```py
-class TestIter:
-    def __next__(self) -> int:
-        return 42
-
-class Test:
-    def __iter__(self) -> TestIter:
-        return TestIter()
-
-class Test2:
-    def __iter__(self) -> int:
-        return 42
-
-def coinflip() -> bool:
-    return True
-
-# error: "Object of type `Test | Test2` is not iterable"
-for x in Test() if coinflip() else Test2():
-    reveal_type(x)  # revealed: Unknown
-```
-
-## Union type as iterator where one union element has no `__next__` method
-
-```py
-class TestIter:
-    def __next__(self) -> int:
-        return 42
-
-class Test:
-    def __iter__(self) -> TestIter | int:
-        return TestIter()
-
-# error: [not-iterable] "Object of type `Test` is not iterable"
-for x in Test():
-    reveal_type(x)  # revealed: Unknown
-```

crates/red_knot_python_semantic/resources/mdtest/metaclass.md

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

crates/red_knot_python_semantic/resources/mdtest/mro.md

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

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

@@ -1,93 +0,0 @@
-# Narrowing in boolean expressions
-
-In `or` expressions, the right-hand side is evaluated only if the left-hand side is **falsy**. So
-when the right-hand side is evaluated, we know the left side has failed.
-
-Similarly, in `and` expressions, the right-hand side is evaluated only if the left-hand side is
-**truthy**. So when the right-hand side is evaluated, we know the left side has succeeded.
-
-## Narrowing in `or`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None = A() if bool_instance() else None
-
-isinstance(x, A) or reveal_type(x)  # revealed: None
-x is None or reveal_type(x)  # revealed: A
-reveal_type(x)  # revealed: A | None
-```
-
-## Narrowing in `and`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None = A() if bool_instance() else None
-
-isinstance(x, A) and reveal_type(x)  # revealed: A
-x is None and reveal_type(x)  # revealed: None
-reveal_type(x)  # revealed: A | None
-```
-
-## Multiple `and` arms
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None = A() if bool_instance() else None
-
-bool_instance() and isinstance(x, A) and reveal_type(x)  # revealed: A
-isinstance(x, A) and bool_instance() and reveal_type(x)  # revealed: A
-reveal_type(x) and isinstance(x, A) and bool_instance()  # revealed: A | None
-```
-
-## Multiple `or` arms
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None = A() if bool_instance() else None
-
-bool_instance() or isinstance(x, A) or reveal_type(x)  # revealed: None
-isinstance(x, A) or bool_instance() or reveal_type(x)  # revealed: None
-reveal_type(x) or isinstance(x, A) or bool_instance()  # revealed: A | None
-```
-
-## Multiple predicates
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
-
-x is None or isinstance(x, A) or reveal_type(x)  # revealed: Literal[1]
-```
-
-## Mix of `and` and `or`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x: A | None | Literal[1] = A() if bool_instance() else None if bool_instance() else 1
-
-isinstance(x, A) or x is not None and reveal_type(x)  # revealed: Literal[1]
-```

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

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

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

@@ -1,57 +0,0 @@
-# Narrowing for conditionals with elif and else
-
-## Positive contributions become negative in elif-else blocks
-
-```py
-def int_instance() -> int:
-    return 42
-
-x = int_instance()
-
-if x == 1:
-    # cannot narrow; could be a subclass of `int`
-    reveal_type(x)  # revealed: int
-elif x == 2:
-    reveal_type(x)  # revealed: int & ~Literal[1]
-elif x != 3:
-    reveal_type(x)  # revealed: int & ~Literal[1] & ~Literal[2] & ~Literal[3]
-```
-
-## Positive contributions become negative in elif-else blocks, with simplification
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else 2 if bool_instance() else 3
-
-if x == 1:
-    # TODO should be Literal[1]
-    reveal_type(x)  # revealed: Literal[1, 2, 3]
-elif x == 2:
-    # TODO should be Literal[2]
-    reveal_type(x)  # revealed: Literal[2, 3]
-else:
-    reveal_type(x)  # revealed: Literal[3]
-```
-
-## Multiple negative contributions using elif, with simplification
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else 2 if bool_instance() else 3
-
-if x != 1:
-    reveal_type(x)  # revealed: Literal[2, 3]
-elif x != 2:
-    # TODO should be `Literal[1]`
-    reveal_type(x)  # revealed: Literal[1, 3]
-elif x == 3:
-    # TODO should be Never
-    reveal_type(x)  # revealed: Literal[1, 2, 3]
-else:
-    # TODO should be Never
-    reveal_type(x)  # revealed: Literal[1, 2]
-```

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

@@ -11,8 +11,6 @@ x = None if flag else 1
 
 if x is None:
     reveal_type(x)  # revealed: None
-else:
-    reveal_type(x)  # revealed: Literal[1]
 
 reveal_type(x)  # revealed: None | Literal[1]
 ```
@@ -32,8 +30,6 @@ y = x if flag else None
 
 if y is x:
     reveal_type(y)  # revealed: A
-else:
-    reveal_type(y)  # revealed: A | None
 
 reveal_type(y)  # revealed: A | None
 ```
@@ -54,26 +50,4 @@ reveal_type(y)  # revealed: bool
 if y is x is False:  # Interpreted as `(y is x) and (x is False)`
     reveal_type(x)  # revealed: Literal[False]
     reveal_type(y)  # revealed: bool
-else:
-    # The negation of the clause above is (y is not x) or (x is not False)
-    # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-    reveal_type(x)  # revealed: bool
-    reveal_type(y)  # revealed: bool
-```
-
-## `is` in elif clause
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = None if bool_instance() else (1 if bool_instance() else True)
-
-reveal_type(x)  # revealed: None | Literal[1] | Literal[True]
-if x is None:
-    reveal_type(x)  # revealed: None
-elif x is True:
-    reveal_type(x)  # revealed: Literal[True]
-else:
-    reveal_type(x)  # revealed: Literal[1]
 ```

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

@@ -13,8 +13,6 @@ x = None if flag else 1
 
 if x is not None:
     reveal_type(x)  # revealed: Literal[1]
-else:
-    reveal_type(x)  # revealed: None
 
 reveal_type(x)  # revealed: None | Literal[1]
 ```
@@ -31,14 +29,13 @@ reveal_type(x)  # revealed: bool
 
 if x is not False:
     reveal_type(x)  # revealed: Literal[True]
-else:
-    reveal_type(x)  # revealed: Literal[False]
 ```
 
 ## `is not` for non-singleton types
 
-Non-singleton types should *not* narrow the type: two instances of a non-singleton class may occupy
-different addresses in memory even if they compare equal.
+Non-singleton types should *not* narrow the type: two instances of a
+non-singleton class may occupy different addresses in memory even if
+they compare equal.
 
 ```py
 x = 345
@@ -46,27 +43,6 @@ y = 345
 
 if x is not y:
     reveal_type(x)  # revealed: Literal[345]
-else:
-    reveal_type(x)  # revealed: Literal[345]
-```
-
-## `is not` for other types
-
-```py
-def bool_instance() -> bool:
-    return True
-
-class A: ...
-
-x = A()
-y = x if bool_instance() else None
-
-if y is not x:
-    reveal_type(y)  # revealed: A | None
-else:
-    reveal_type(y)  # revealed: A
-
-reveal_type(y)  # revealed: A | None
 ```
 
 ## `is not` in chained comparisons
@@ -87,10 +63,4 @@ reveal_type(y)  # revealed: bool
 if y is not x is not False:  # Interpreted as `(y is not x) and (x is not False)`
     reveal_type(x)  # revealed: Literal[True]
     reveal_type(y)  # revealed: bool
-else:
-    # The negation of the clause above is (y is x) or (x is False)
-    # So we can't narrow the type of x or y here, because each arm of the `or` could be true
-
-    reveal_type(x)  # revealed: bool
-    reveal_type(y)  # revealed: bool
 ```

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

@@ -3,8 +3,7 @@
 ## Multiple negative contributions
 
 ```py
-def int_instance() -> int:
-    return 42
+def int_instance() -> int: ...
 
 x = int_instance()
 
@@ -28,29 +27,3 @@ if x != 1:
     if x != 2:
         reveal_type(x)  # revealed: Literal[3]
 ```
-
-## elif-else blocks
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else 2 if bool_instance() else 3
-
-if x != 1:
-    reveal_type(x)  # revealed: Literal[2, 3]
-    if x == 2:
-        # TODO should be `Literal[2]`
-        reveal_type(x)  # revealed: Literal[2, 3]
-    elif x == 3:
-        reveal_type(x)  # revealed: Literal[3]
-    else:
-        reveal_type(x)  # revealed: Never
-
-elif x != 2:
-    # TODO should be Literal[1]
-    reveal_type(x)  # revealed: Literal[1, 3]
-else:
-    # TODO should be Never
-    reveal_type(x)  # revealed: Literal[1, 2, 3]
-```

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

@@ -1,33 +0,0 @@
-# Narrowing for `not` conditionals
-
-The `not` operator negates a constraint.
-
-## `not is None`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = None if bool_instance() else 1
-
-if not x is None:
-    reveal_type(x)  # revealed: Literal[1]
-else:
-    reveal_type(x)  # revealed: None
-
-reveal_type(x)  # revealed: None | Literal[1]
-```
-
-## `not isinstance`
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else "a"
-
-if not isinstance(x, (int)):
-    reveal_type(x)  # revealed: Literal["a"]
-else:
-    reveal_type(x)  # revealed: Literal[1]
-```

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

@@ -11,9 +11,6 @@ x = None if flag else 1
 
 if x != None:
     reveal_type(x)  # revealed: Literal[1]
-else:
-    # TODO should be None
-    reveal_type(x)  # revealed: None | Literal[1]
 ```
 
 ## `!=` for other singleton types
@@ -27,9 +24,6 @@ x = True if flag else False
 
 if x != False:
     reveal_type(x)  # revealed: Literal[True]
-else:
-    # TODO should be Literal[False]
-    reveal_type(x)  # revealed: bool
 ```
 
 ## `x != y` where `y` is of literal type
@@ -60,25 +54,6 @@ C = A if flag else B
 
 if C != A:
     reveal_type(C)  # revealed: Literal[B]
-else:
-    # TODO should be Literal[A]
-    reveal_type(C)  # revealed: Literal[A, B]
-```
-
-## `x != y` where `y` has multiple single-valued options
-
-```py
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else 2
-y = 2 if bool_instance() else 3
-
-if x != y:
-    reveal_type(x)  # revealed: Literal[1, 2]
-else:
-    # TODO should be Literal[2]
-    reveal_type(x)  # revealed: Literal[1, 2]
 ```
 
 ## `!=` for non-single-valued types
@@ -99,21 +74,3 @@ y = int_instance()
 if x != y:
     reveal_type(x)  # revealed: int | None
 ```
-
-## Mix of single-valued and non-single-valued types
-
-```py
-def int_instance() -> int:
-    return 42
-
-def bool_instance() -> bool:
-    return True
-
-x = 1 if bool_instance() else 2
-y = 2 if bool_instance() else int_instance()
-
-if x != y:
-    reveal_type(x)  # revealed: Literal[1, 2]
-else:
-    reveal_type(x)  # revealed: Literal[1, 2]
-```

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

@@ -26,8 +26,9 @@ if isinstance(x, (int, object)):
 
 ## `classinfo` is a tuple of types
 
-Note: `isinstance(x, (int, str))` should not be confused with `isinstance(x, tuple[(int, str)])`.
-The former is equivalent to `isinstance(x, int | str)`:
+Note: `isinstance(x, (int, str))` should not be confused with
+`isinstance(x, tuple[(int, str)])`. The former is equivalent to
+`isinstance(x, int | str)`:
 
 ```py
 def bool_instance() -> bool:
@@ -39,8 +40,6 @@ x = 1 if flag else "a"
 
 if isinstance(x, (int, str)):
     reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-else:
-    reveal_type(x)  # revealed: Never
 
 if isinstance(x, (int, bytes)):
     reveal_type(x)  # revealed: Literal[1]
@@ -52,8 +51,6 @@ if isinstance(x, (bytes, str)):
 # one of the possibilities:
 if isinstance(x, (int, object)):
     reveal_type(x)  # revealed: Literal[1] | Literal["a"]
-else:
-    reveal_type(x)  # revealed: Never
 
 y = 1 if flag1 else "a" if flag2 else b"b"
 if isinstance(y, (int, str)):
@@ -78,8 +75,6 @@ x = 1 if flag else "a"
 
 if isinstance(x, (bool, (bytes, int))):
     reveal_type(x)  # revealed: Literal[1]
-else:
-    reveal_type(x)  # revealed: Literal["a"]
 ```
 
 ## Class types
@@ -87,7 +82,6 @@ else:
 ```py
 class A: ...
 class B: ...
-class C: ...
 
 def get_object() -> object: ...
 
@@ -97,16 +91,6 @@ if isinstance(x, A):
     reveal_type(x)  # revealed: A
     if isinstance(x, B):
         reveal_type(x)  # revealed: A & B
-    else:
-        reveal_type(x)  # revealed: A & ~B
-
-if isinstance(x, (A, B)):
-    reveal_type(x)  # revealed: A | B
-elif isinstance(x, (A, C)):
-    reveal_type(x)  # revealed: C & ~A & ~B
-else:
-    # TODO: Should be simplified to ~A & ~B & ~C
-    reveal_type(x)  # revealed: object & ~A & ~B & ~C
 ```
 
 ## No narrowing for instances of `builtins.type`

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

@@ -1,244 +0,0 @@
-# Narrowing for `issubclass` checks
-
-Narrowing for `issubclass(class, classinfo)` expressions.
-
-## `classinfo` is a single type
-
-### Basic example
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-if issubclass(t, bytes):
-    reveal_type(t)  # revealed: Never
-
-if issubclass(t, object):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-else:
-    reveal_type(t)  # revealed: Literal[str]
-
-if issubclass(t, str):
-    reveal_type(t)  # revealed: Literal[str]
-    if issubclass(t, int):
-        reveal_type(t)  # revealed: Never
-```
-
-### Proper narrowing in `elif` and `else` branches
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str if flag() else bytes
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-else:
-    reveal_type(t)  # revealed: Literal[str, bytes]
-
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-elif issubclass(t, str):
-    reveal_type(t)  # revealed: Literal[str]
-else:
-    reveal_type(t)  # revealed: Literal[bytes]
-```
-
-### Multiple derived classes
-
-```py
-class Base: ...
-class Derived1(Base): ...
-class Derived2(Base): ...
-class Unrelated: ...
-
-def flag() -> bool: ...
-
-t1 = Derived1 if flag() else Derived2
-
-if issubclass(t1, Base):
-    reveal_type(t1)  # revealed: Literal[Derived1, Derived2]
-
-if issubclass(t1, Derived1):
-    reveal_type(t1)  # revealed: Literal[Derived1]
-else:
-    reveal_type(t1)  # revealed: Literal[Derived2]
-
-t2 = Derived1 if flag() else Base
-
-if issubclass(t2, Base):
-    reveal_type(t2)  # revealed: Literal[Derived1, Base]
-
-t3 = Derived1 if flag() else Unrelated
-
-if issubclass(t3, Base):
-    reveal_type(t3)  # revealed: Literal[Derived1]
-else:
-    reveal_type(t3)  # revealed: Literal[Unrelated]
-```
-
-### Narrowing for non-literals
-
-```py
-class A: ...
-class B: ...
-
-def get_class() -> type[object]: ...
-
-t = get_class()
-
-if issubclass(t, A):
-    reveal_type(t)  # revealed: type[A]
-    if issubclass(t, B):
-        reveal_type(t)  # revealed: type[A] & type[B]
-else:
-    reveal_type(t)  # revealed: type[object] & ~type[A]
-```
-
-### Handling of `None`
-
-```py
-from types import NoneType
-
-def flag() -> bool: ...
-
-t = int if flag() else NoneType
-
-if issubclass(t, NoneType):
-    reveal_type(t)  # revealed: Literal[NoneType]
-
-if issubclass(t, type(None)):
-    # TODO: this should be just `Literal[NoneType]`
-    reveal_type(t)  # revealed: Literal[int, NoneType]
-```
-
-## `classinfo` contains multiple types
-
-### (Nested) tuples of types
-
-```py
-class Unrelated: ...
-
-def flag() -> bool: ...
-
-t = int if flag() else str if flag() else bytes
-
-if issubclass(t, (int, (Unrelated, (bytes,)))):
-    reveal_type(t)  # revealed: Literal[int, bytes]
-else:
-    reveal_type(t)  # revealed: Literal[str]
-```
-
-## Special cases
-
-### Emit a diagnostic if the first argument is of wrong type
-
-#### Too wide
-
-`type[object]` is a subtype of `object`, but not every `object` can be passed as the first argument
-to `issubclass`:
-
-```py
-class A: ...
-
-def get_object() -> object: ...
-
-t = get_object()
-
-# TODO: we should emit a diagnostic here
-if issubclass(t, A):
-    reveal_type(t)  # revealed: type[A]
-```
-
-#### Wrong
-
-`Literal[1]` and `type` are entirely disjoint, so the inferred type of `Literal[1] & type[int]` is
-eagerly simplified to `Never` as a result of the type narrowing in the `if issubclass(t, int)`
-branch:
-
-```py
-t = 1
-
-# TODO: we should emit a diagnostic here
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Never
-```
-
-### Do not use custom `issubclass` for narrowing
-
-```py
-def issubclass(c, ci):
-    return True
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int, str]
-```
-
-### Do support narrowing if `issubclass` is aliased
-
-```py
-issubclass_alias = issubclass
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if issubclass_alias(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-```
-
-### Do support narrowing if `issubclass` is imported
-
-```py
-from builtins import issubclass as imported_issubclass
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-if imported_issubclass(t, int):
-    reveal_type(t)  # revealed: Literal[int]
-```
-
-### Do not narrow if second argument is not a proper `classinfo` argument
-
-```py
-from typing import Any
-
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, "str"):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, (bytes, "str")):
-    reveal_type(t)  # revealed: Literal[int, str]
-
-# TODO: this should cause us to emit a diagnostic during
-# type checking
-if issubclass(t, Any):
-    reveal_type(t)  # revealed: Literal[int, str]
-```
-
-### Do not narrow if there are keyword arguments
-
-```py
-def flag() -> bool: ...
-
-t = int if flag() else str
-
-# TODO: this should cause us to emit a diagnostic
-# (`issubclass` has no `foo` parameter)
-if issubclass(t, int, foo="bar"):
-    reveal_type(t)  # revealed: Literal[int, str]
-```

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

@@ -1,136 +0,0 @@
-# Implicit globals from `types.ModuleType`
-
-## Implicit `ModuleType` globals
-
-All modules are instances of `types.ModuleType`. If a name can't be found in any local or global
-scope, we look it up as an attribute on `types.ModuleType` in typeshed before deciding that the name
-is unbound.
-
-```py
-reveal_type(__name__)  # revealed: str
-reveal_type(__file__)  # revealed: str | None
-reveal_type(__loader__)  # revealed: LoaderProtocol | None
-reveal_type(__package__)  # revealed: str | None
-reveal_type(__doc__)  # revealed: str | None
-
-# TODO: Should be `ModuleSpec | None`
-# (needs support for `*` imports)
-reveal_type(__spec__)  # revealed: Unknown | None
-
-# TODO: generics
-reveal_type(__path__)  # revealed: @Todo
-
-class X:
-    reveal_type(__name__)  # revealed: str
-
-def foo():
-    reveal_type(__name__)  # revealed: str
-```
-
-However, three attributes on `types.ModuleType` are not present as implicit module globals; these
-are excluded:
-
-```py path=unbound_dunders.py
-# error: [unresolved-reference]
-# revealed: Unknown
-reveal_type(__getattr__)
-
-# error: [unresolved-reference]
-# revealed: Unknown
-reveal_type(__dict__)
-
-# error: [unresolved-reference]
-# revealed: Unknown
-reveal_type(__init__)
-```
-
-## Accessed as attributes
-
-`ModuleType` attributes can also be accessed as attributes on module-literal types. The special
-attributes `__dict__` and `__init__`, and all attributes on `builtins.object`, can also be accessed
-as attributes on module-literal types, despite the fact that these are inaccessible as globals from
-inside the module:
-
-```py
-import typing
-
-reveal_type(typing.__name__)  # revealed: str
-reveal_type(typing.__init__)  # revealed: Literal[__init__]
-
-# These come from `builtins.object`, not `types.ModuleType`:
-reveal_type(typing.__eq__)  # revealed: Literal[__eq__]
-
-reveal_type(typing.__class__)  # revealed: Literal[type]
-
-# TODO: needs support for attribute access on instances, properties and generics;
-# should be `dict[str, Any]`
-reveal_type(typing.__dict__)  # revealed: @Todo
-```
-
-Typeshed includes a fake `__getattr__` method in the stub for `types.ModuleType` to help out with
-dynamic imports; but we ignore that for module-literal types where we know exactly which module
-we're dealing with:
-
-```py path=__getattr__.py
-import typing
-
-reveal_type(typing.__getattr__)  # revealed: Unknown
-```
-
-## `types.ModuleType.__dict__` takes precedence over global variable `__dict__`
-
-It's impossible to override the `__dict__` attribute of `types.ModuleType` instances from inside the
-module; we should prioritise the attribute in the `types.ModuleType` stub over a variable named
-`__dict__` in the module's global namespace:
-
-```py path=foo.py
-__dict__ = "foo"
-
-reveal_type(__dict__)  # revealed: Literal["foo"]
-```
-
-```py path=bar.py
-import foo
-from foo import __dict__ as foo_dict
-
-# TODO: needs support for attribute access on instances, properties, and generics;
-# should be `dict[str, Any]` for both of these:
-reveal_type(foo.__dict__)  # revealed: @Todo
-reveal_type(foo_dict)  # revealed: @Todo
-```
-
-## Conditionally global or `ModuleType` attribute
-
-Attributes overridden in the module namespace take priority. If a builtin name is conditionally
-defined as a global, however, a name lookup should union the `ModuleType` type with the
-conditionally defined type:
-
-```py
-__file__ = 42
-
-def returns_bool() -> bool:
-    return True
-
-if returns_bool():
-    __name__ = 1
-
-reveal_type(__file__)  # revealed: Literal[42]
-reveal_type(__name__)  # revealed: Literal[1] | str
-```
-
-## Conditionally global or `ModuleType` attribute, with annotation
-
-The same is true if the name is annotated:
-
-```py
-__file__: int = 42
-
-def returns_bool() -> bool:
-    return True
-
-if returns_bool():
-    __name__: int = 1
-
-reveal_type(__file__)  # revealed: Literal[42]
-reveal_type(__name__)  # revealed: Literal[1] | str
-```

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

@@ -2,8 +2,7 @@
 
 ## Parameter
 
-Parameter `x` of type `str` is shadowed and reassigned with a new `int` value inside the function.
-No diagnostics should be generated.
+Parameter `x` of type `str` is shadowed and reassigned with a new `int` value inside the function. No diagnostics should be generated.
 
 ```py path=a.py
 def f(x: str):

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

@@ -2,16 +2,10 @@
 
 ## Cyclical class definition
 
-In type stubs, classes can reference themselves in their base class definitions. For example, in
-`typeshed`, we have `class str(Sequence[str]): ...`.
+In type stubs, classes can reference themselves in their base class definitions. For example, in `typeshed`, we have `class str(Sequence[str]): ...`.
 
 ```py path=a.pyi
-class Foo[T]: ...
+class C(C): ...
 
-# TODO: actually is subscriptable
-# error: [non-subscriptable]
-class Bar(Foo[Bar]): ...
-
-reveal_type(Bar)  # revealed: Literal[Bar]
-reveal_type(Bar.__mro__)  # revealed: tuple[Literal[Bar], Unknown, Literal[object]]
+reveal_type(C)  # revealed: Literal[C]
 ```

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

@@ -1,6 +1,6 @@
-# Bytes subscripts
+# Bytes subscript
 
-## Indexing
+## Simple
 
 ```py
 b = b"\x00abc\xff"
@@ -21,37 +21,14 @@ reveal_type(x)  # revealed: Unknown
 
 y = b[-6]  # error: [index-out-of-bounds] "Index -6 is out of bounds for bytes literal `Literal[b"\x00abc\xff"]` with length 5"
 reveal_type(y)  # revealed: Unknown
+```
 
-def int_instance() -> int:
-    return 42
+## Function return
+
+```py
+def int_instance() -> int: ...
 
 a = b"abcde"[int_instance()]
 # TODO: Support overloads... Should be `bytes`
 reveal_type(a)  # revealed: @Todo
 ```
-
-## Slices
-
-```py
-b = b"\x00abc\xff"
-
-reveal_type(b[0:2])  # revealed: Literal[b"\x00a"]
-reveal_type(b[-3:])  # revealed: Literal[b"bc\xff"]
-
-b[0:4:0]  # error: [zero-stepsize-in-slice]
-b[:4:0]  # error: [zero-stepsize-in-slice]
-b[0::0]  # error: [zero-stepsize-in-slice]
-b[::0]  # error: [zero-stepsize-in-slice]
-
-def int_instance() -> int: ...
-
-byte_slice1 = b[int_instance() : int_instance()]
-# TODO: Support overloads... Should be `bytes`
-reveal_type(byte_slice1)  # revealed: @Todo
-
-def bytes_instance() -> bytes: ...
-
-byte_slice2 = bytes_instance()[0:5]
-# TODO: Support overloads... Should be `bytes`
-reveal_type(byte_slice2)  # revealed: @Todo
-```

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

@@ -39,8 +39,7 @@ reveal_type(UnionClassGetItem[0])  # revealed: str | int
 ## Class getitem with class union
 
 ```py
-def bool_instance() -> bool:
-    return True
+flag = True
 
 class A:
     def __class_getitem__(cls, item: int) -> str:
@@ -50,7 +49,7 @@ class B:
     def __class_getitem__(cls, item: int) -> int:
         return item
 
-x = A if bool_instance() else B
+x = A if flag else B
 
 reveal_type(x)  # revealed: Literal[A, B]
 reveal_type(x[0])  # revealed: str | int
@@ -69,8 +68,8 @@ if flag:
 else:
     class Spam: ...
 
-# error: [call-possibly-unbound-method] "Method `__class_getitem__` of type `Literal[Spam, Spam]` is possibly unbound"
-# revealed: str
+# error: [call-non-callable] "Method `__class_getitem__` of type `Literal[__class_getitem__] | Unbound` is not callable on object of type `Literal[Spam, Spam]`"
+# revealed: str | Unknown
 reveal_type(Spam[42])
 ```
 

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

@@ -23,7 +23,8 @@ reveal_type(x["a"])  # revealed: @Todo
 
 ## Assignments within list assignment
 
-In assignment, we might also have a named assignment. This should also get type checked.
+In assignment, we might also have a named assignment.
+This should also get type checked.
 
 ```py
 x = [1, 2, 3]

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

@@ -1,13 +0,0 @@
-# Stepsize zero in slices
-
-We raise a `zero-stepsize-in-slice` diagnostic when trying to slice a literal string, bytes, or
-tuple with a step size of zero (see tests in `string.md`, `bytes.md` and `tuple.md`). But we don't
-want to raise this diagnostic when slicing a custom type:
-
-```py
-class MySequence:
-    def __getitem__(self, s: slice) -> int:
-        return 0
-
-MySequence()[0:1:0]  # No error
-```

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

@@ -1,6 +1,6 @@
-# String subscripts
+# Subscript on strings
 
-## Indexing
+## Simple
 
 ```py
 s = "abcde"
@@ -18,82 +18,14 @@ reveal_type(a)  # revealed: Unknown
 
 b = s[-8]  # error: [index-out-of-bounds] "Index -8 is out of bounds for string `Literal["abcde"]` with length 5"
 reveal_type(b)  # revealed: Unknown
+```
 
+## Function return
+
+```py
 def int_instance() -> int: ...
 
 a = "abcde"[int_instance()]
 # TODO: Support overloads... Should be `str`
 reveal_type(a)  # revealed: @Todo
 ```
-
-## Slices
-
-```py
-s = "abcde"
-
-reveal_type(s[0:0])  # revealed: Literal[""]
-reveal_type(s[0:1])  # revealed: Literal["a"]
-reveal_type(s[0:2])  # revealed: Literal["ab"]
-reveal_type(s[0:5])  # revealed: Literal["abcde"]
-reveal_type(s[0:6])  # revealed: Literal["abcde"]
-reveal_type(s[1:3])  # revealed: Literal["bc"]
-
-reveal_type(s[-3:5])  # revealed: Literal["cde"]
-reveal_type(s[-4:-2])  # revealed: Literal["bc"]
-reveal_type(s[-10:10])  # revealed: Literal["abcde"]
-
-reveal_type(s[0:])  # revealed: Literal["abcde"]
-reveal_type(s[2:])  # revealed: Literal["cde"]
-reveal_type(s[5:])  # revealed: Literal[""]
-reveal_type(s[:2])  # revealed: Literal["ab"]
-reveal_type(s[:0])  # revealed: Literal[""]
-reveal_type(s[:2])  # revealed: Literal["ab"]
-reveal_type(s[:10])  # revealed: Literal["abcde"]
-reveal_type(s[:])  # revealed: Literal["abcde"]
-
-reveal_type(s[::-1])  # revealed: Literal["edcba"]
-reveal_type(s[::2])  # revealed: Literal["ace"]
-reveal_type(s[-2:-5:-1])  # revealed: Literal["dcb"]
-reveal_type(s[::-2])  # revealed: Literal["eca"]
-reveal_type(s[-1::-3])  # revealed: Literal["eb"]
-
-reveal_type(s[None:2:None])  # revealed: Literal["ab"]
-reveal_type(s[1:None:1])  # revealed: Literal["bcde"]
-reveal_type(s[None:None:None])  # revealed: Literal["abcde"]
-
-start = 1
-stop = None
-step = 2
-reveal_type(s[start:stop:step])  # revealed: Literal["bd"]
-
-reveal_type(s[False:True])  # revealed: Literal["a"]
-reveal_type(s[True:3])  # revealed: Literal["bc"]
-
-s[0:4:0]  # error: [zero-stepsize-in-slice]
-s[:4:0]  # error: [zero-stepsize-in-slice]
-s[0::0]  # error: [zero-stepsize-in-slice]
-s[::0]  # error: [zero-stepsize-in-slice]
-
-def int_instance() -> int: ...
-
-substring1 = s[int_instance() : int_instance()]
-# TODO: Support overloads... Should be `LiteralString`
-reveal_type(substring1)  # revealed: @Todo
-
-def str_instance() -> str: ...
-
-substring2 = str_instance()[0:5]
-# TODO: Support overloads... Should be `str`
-reveal_type(substring2)  # revealed: @Todo
-```
-
-## Unsupported slice types
-
-```py
-# TODO: It would be great if we raised an error here. This can be done once
-# we have support for overloads and generics, and once typeshed has a more
-# precise annotation for `str.__getitem__`, that makes use of the generic
-# `slice[..]` type. We could then infer `slice[str, str]` here and see that
-# it doesn't match the signature of `str.__getitem__`.
-"foo"["bar":"baz"]
-```

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

@@ -1,6 +1,6 @@
 # Tuple subscripts
 
-## Indexing
+## Basic
 
 ```py
 t = (1, "a", "b")
@@ -10,66 +10,9 @@ reveal_type(t[1])  # revealed: Literal["a"]
 reveal_type(t[-1])  # revealed: Literal["b"]
 reveal_type(t[-2])  # revealed: Literal["a"]
 
-reveal_type(t[False])  # revealed: Literal[1]
-reveal_type(t[True])  # revealed: Literal["a"]
-
 a = t[4]  # error: [index-out-of-bounds]
 reveal_type(a)  # revealed: Unknown
 
 b = t[-4]  # error: [index-out-of-bounds]
 reveal_type(b)  # revealed: Unknown
 ```
-
-## Slices
-
-```py
-t = (1, "a", None, b"b")
-
-reveal_type(t[0:0])  # revealed: tuple[()]
-reveal_type(t[0:1])  # revealed: tuple[Literal[1]]
-reveal_type(t[0:2])  # revealed: tuple[Literal[1], Literal["a"]]
-reveal_type(t[0:4])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-reveal_type(t[0:5])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-reveal_type(t[1:3])  # revealed: tuple[Literal["a"], None]
-
-reveal_type(t[-2:4])  # revealed: tuple[None, Literal[b"b"]]
-reveal_type(t[-3:-1])  # revealed: tuple[Literal["a"], None]
-reveal_type(t[-10:10])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-
-reveal_type(t[0:])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-reveal_type(t[2:])  # revealed: tuple[None, Literal[b"b"]]
-reveal_type(t[4:])  # revealed: tuple[()]
-reveal_type(t[:0])  # revealed: tuple[()]
-reveal_type(t[:2])  # revealed: tuple[Literal[1], Literal["a"]]
-reveal_type(t[:10])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-reveal_type(t[:])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-
-reveal_type(t[::-1])  # revealed: tuple[Literal[b"b"], None, Literal["a"], Literal[1]]
-reveal_type(t[::2])  # revealed: tuple[Literal[1], None]
-reveal_type(t[-2:-5:-1])  # revealed: tuple[None, Literal["a"], Literal[1]]
-reveal_type(t[::-2])  # revealed: tuple[Literal[b"b"], Literal["a"]]
-reveal_type(t[-1::-3])  # revealed: tuple[Literal[b"b"], Literal[1]]
-
-reveal_type(t[None:2:None])  # revealed: tuple[Literal[1], Literal["a"]]
-reveal_type(t[1:None:1])  # revealed: tuple[Literal["a"], None, Literal[b"b"]]
-reveal_type(t[None:None:None])  # revealed: tuple[Literal[1], Literal["a"], None, Literal[b"b"]]
-
-start = 1
-stop = None
-step = 2
-reveal_type(t[start:stop:step])  # revealed: tuple[Literal["a"], Literal[b"b"]]
-
-reveal_type(t[False:True])  # revealed: tuple[Literal[1]]
-reveal_type(t[True:3])  # revealed: tuple[Literal["a"], None]
-
-t[0:4:0]  # error: [zero-stepsize-in-slice]
-t[:4:0]  # error: [zero-stepsize-in-slice]
-t[0::0]  # error: [zero-stepsize-in-slice]
-t[::0]  # error: [zero-stepsize-in-slice]
-
-def int_instance() -> int: ...
-
-tuple_slice = t[int_instance() : int_instance()]
-# TODO: Support overloads... Should be `tuple[Literal[1, 'a', b"b"] | None, ...]`
-reveal_type(tuple_slice)  # revealed: @Todo
-```

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

@@ -1,8 +1,6 @@
 # Unary Operations
 
 ```py
-from typing import Literal
-
 class Number:
     def __init__(self, value: int):
         self.value = 1
@@ -20,7 +18,7 @@ a = Number()
 
 reveal_type(+a)  # revealed: int
 reveal_type(-a)  # revealed: int
-reveal_type(~a)  # revealed: Literal[True]
+reveal_type(~a)  # revealed: @Todo
 
 class NoDunder: ...
 

crates/red_knot_python_semantic/resources/mdtest/unpacking.md

@@ -81,7 +81,8 @@ reveal_type(b)  # revealed: Literal[2]
 
 ```py
 # TODO: Add diagnostic (need more values to unpack)
-[a, *b, c, d] = (1, 2)
+# TODO: Remove 'not-iterable' diagnostic
+[a, *b, c, d] = (1, 2)  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: Literal[1]
 # TODO: Should be list[Any] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -92,7 +93,7 @@ reveal_type(d)  # revealed: Unknown
 ### Starred expression (2)
 
 ```py
-[a, *b, c] = (1, 2)
+[a, *b, c] = (1, 2)  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: Literal[1]
 # TODO: Should be list[Any] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -102,7 +103,8 @@ reveal_type(c)  # revealed: Literal[2]
 ### Starred expression (3)
 
 ```py
-[a, *b, c] = (1, 2, 3)
+# TODO: Remove 'not-iterable' diagnostic
+[a, *b, c] = (1, 2, 3)  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: Literal[1]
 # TODO: Should be list[int] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -112,7 +114,8 @@ reveal_type(c)  # revealed: Literal[3]
 ### Starred expression (4)
 
 ```py
-[a, *b, c, d] = (1, 2, 3, 4, 5, 6)
+# TODO: Remove 'not-iterable' diagnostic
+[a, *b, c, d] = (1, 2, 3, 4, 5, 6)  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: Literal[1]
 # TODO: Should be list[int] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -123,30 +126,23 @@ reveal_type(d)  # revealed: Literal[6]
 ### Starred expression (5)
 
 ```py
-[a, b, *c] = (1, 2, 3, 4)
+# TODO: Remove 'not-iterable' diagnostic
+[a, b, *c] = (1, 2, 3, 4)  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: Literal[1]
 reveal_type(b)  # revealed: Literal[2]
 # TODO: Should be list[int] once support for assigning to starred expression is added
 reveal_type(c)  # revealed: @Todo
 ```
 
-### Starred expression (6)
-
-```py
-# TODO: Add diagnostic (need more values to unpack)
-(a, b, c, *d, e, f) = (1,)
-reveal_type(a)  # revealed: Literal[1]
-reveal_type(b)  # revealed: Unknown
-reveal_type(c)  # revealed: Unknown
-reveal_type(d)  # revealed: @Todo
-reveal_type(e)  # revealed: Unknown
-reveal_type(f)  # revealed: Unknown
-```
-
 ### Non-iterable unpacking
 
+TODO: Remove duplicate diagnostics. This is happening because for a sequence-like
+assignment target, multiple definitions are created and the inference engine runs
+on each of them which results in duplicate diagnostics.
+
 ```py
 # error: "Object of type `Literal[1]` is not iterable"
+# error: "Object of type `Literal[1]` is not iterable"
 a, b = 1
 reveal_type(a)  # revealed: Unknown
 reveal_type(b)  # revealed: Unknown
@@ -219,7 +215,8 @@ reveal_type(b)  # revealed: LiteralString
 
 ```py
 # TODO: Add diagnostic (need more values to unpack)
-(a, *b, c, d) = "ab"
+# TODO: Remove 'not-iterable' diagnostic
+(a, *b, c, d) = "ab"  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: LiteralString
 # TODO: Should be list[LiteralString] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -230,7 +227,7 @@ reveal_type(d)  # revealed: Unknown
 ### Starred expression (2)
 
 ```py
-(a, *b, c) = "ab"
+(a, *b, c) = "ab"  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: LiteralString
 # TODO: Should be list[Any] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -240,7 +237,8 @@ reveal_type(c)  # revealed: LiteralString
 ### Starred expression (3)
 
 ```py
-(a, *b, c) = "abc"
+# TODO: Remove 'not-iterable' diagnostic
+(a, *b, c) = "abc"  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: LiteralString
 # TODO: Should be list[LiteralString] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -250,7 +248,8 @@ reveal_type(c)  # revealed: LiteralString
 ### Starred expression (4)
 
 ```py
-(a, *b, c, d) = "abcdef"
+# TODO: Remove 'not-iterable' diagnostic
+(a, *b, c, d) = "abcdef"  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: LiteralString
 # TODO: Should be list[LiteralString] once support for assigning to starred expression is added
 reveal_type(b)  # revealed: @Todo
@@ -261,7 +260,8 @@ reveal_type(d)  # revealed: LiteralString
 ### Starred expression (5)
 
 ```py
-(a, b, *c) = "abcd"
+# TODO: Remove 'not-iterable' diagnostic
+(a, b, *c) = "abcd"  # error: "Object of type `None` is not iterable"
 reveal_type(a)  # revealed: LiteralString
 reveal_type(b)  # revealed: LiteralString
 # TODO: Should be list[int] once support for assigning to starred expression is added

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

@@ -1,21 +0,0 @@
-# Async with statements
-
-## Basic `async with` statement
-
-The type of the target variable in a `with` statement should be the return type from the context
-manager's `__aenter__` method. However, `async with` statements aren't supported yet. This test
-asserts that it doesn't emit any context manager-related errors.
-
-```py
-class Target: ...
-
-class Manager:
-    async def __aenter__(self) -> Target:
-        return Target()
-
-    async def __aexit__(self, exc_type, exc_value, traceback): ...
-
-async def test():
-    async with Manager() as f:
-        reveal_type(f)  # revealed: @Todo
-```

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

@@ -1,141 +0,0 @@
-# With statements
-
-## Basic `with` statement
-
-The type of the target variable in a `with` statement is the return type from the context manager's
-`__enter__` method.
-
-```py
-class Target: ...
-
-class Manager:
-    def __enter__(self) -> Target:
-        return Target()
-
-    def __exit__(self, exc_type, exc_value, traceback): ...
-
-with Manager() as f:
-    reveal_type(f)  # revealed: Target
-```
-
-## Union context manager
-
-```py
-def coinflip() -> bool:
-    return True
-
-class Manager1:
-    def __enter__(self) -> str:
-        return "foo"
-
-    def __exit__(self, exc_type, exc_value, traceback): ...
-
-class Manager2:
-    def __enter__(self) -> int:
-        return 42
-
-    def __exit__(self, exc_type, exc_value, traceback): ...
-
-context_expr = Manager1() if coinflip() else Manager2()
-
-with context_expr as f:
-    reveal_type(f)  # revealed: str | int
-```
-
-## Context manager without an `__enter__` or `__exit__` method
-
-```py
-class Manager: ...
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because it doesn't implement `__enter__` and `__exit__`"
-with Manager():
-    ...
-```
-
-## Context manager without an `__enter__` method
-
-```py
-class Manager:
-    def __exit__(self, exc_tpe, exc_value, traceback): ...
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because it doesn't implement `__enter__`"
-with Manager():
-    ...
-```
-
-## Context manager without an `__exit__` method
-
-```py
-class Manager:
-    def __enter__(self): ...
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because it doesn't implement `__exit__`"
-with Manager():
-    ...
-```
-
-## Context manager with non-callable `__enter__` attribute
-
-```py
-class Manager:
-    __enter__ = 42
-
-    def __exit__(self, exc_tpe, exc_value, traceback): ...
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` of type `Literal[42]` is not callable"
-with Manager():
-    ...
-```
-
-## Context manager with non-callable `__exit__` attribute
-
-```py
-class Manager:
-    def __enter__(self) -> Self: ...
-
-    __exit__ = 32
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__exit__` of type `Literal[32]` is not callable"
-with Manager():
-    ...
-```
-
-## Context expression with possibly-unbound union variants
-
-```py
-def coinflip() -> bool:
-    return True
-
-class Manager1:
-    def __enter__(self) -> str:
-        return "foo"
-
-    def __exit__(self, exc_type, exc_value, traceback): ...
-
-class NotAContextManager: ...
-
-context_expr = Manager1() if coinflip() else NotAContextManager()
-
-# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-# error: [invalid-context-manager] "Object of type `Manager1 | NotAContextManager` cannot be used with `with` because the method `__exit__` is possibly unbound"
-with context_expr as f:
-    reveal_type(f)  # revealed: str
-```
-
-## Context expression with "sometimes" callable `__enter__` method
-
-```py
-def coinflip() -> bool:
-    return True
-
-class Manager:
-    if coinflip():
-        def __enter__(self) -> str:
-            return "abcd"
-
-    def __exit__(self, *args): ...
-
-# error: [invalid-context-manager] "Object of type `Manager` cannot be used with `with` because the method `__enter__` is possibly unbound"
-with Manager() as f:
-    reveal_type(f)  # revealed: str
-```

crates/red_knot_python_semantic/src/lib.rs

@@ -20,9 +20,7 @@ pub mod semantic_index;
 mod semantic_model;
 pub(crate) mod site_packages;
 mod stdlib;
-pub(crate) mod symbol;
 pub mod types;
-mod unpack;
 mod util;
 
 type FxOrderSet<V> = ordermap::set::OrderSet<V, BuildHasherDefault<FxHasher>>;

crates/red_knot_python_semantic/src/semantic_index.rs

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

crates/red_knot_python_semantic/src/semantic_index/ast_ids.rs

@@ -87,14 +87,6 @@ pub trait HasScopedAstId {
     fn scoped_ast_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id;
 }
 
-impl<T: HasScopedAstId> HasScopedAstId for Box<T> {
-    type Id = <T as HasScopedAstId>::Id;
-
-    fn scoped_ast_id(&self, db: &dyn Db, scope: ScopeId) -> Self::Id {
-        self.as_ref().scoped_ast_id(db, scope)
-    }
-}
-
 /// Uniquely identifies an [`ast::Expr`] in a [`crate::semantic_index::symbol::FileScopeId`].
 #[newtype_index]
 pub struct ScopedExpressionId;

crates/red_knot_python_semantic/src/semantic_index/builder.rs

@@ -9,7 +9,7 @@ use ruff_index::IndexVec;
 use ruff_python_ast as ast;
 use ruff_python_ast::name::Name;
 use ruff_python_ast::visitor::{walk_expr, walk_pattern, walk_stmt, Visitor};
-use ruff_python_ast::{AnyParameterRef, BoolOp, Expr};
+use ruff_python_ast::AnyParameterRef;
 
 use crate::ast_node_ref::AstNodeRef;
 use crate::semantic_index::ast_ids::node_key::ExpressionNodeKey;
@@ -25,13 +25,12 @@ use crate::semantic_index::symbol::{
 };
 use crate::semantic_index::use_def::{FlowSnapshot, UseDefMapBuilder};
 use crate::semantic_index::SemanticIndex;
-use crate::unpack::Unpack;
 use crate::Db;
 
-use super::constraint::{Constraint, ConstraintNode, PatternConstraint};
+use super::constraint::{Constraint, PatternConstraint};
 use super::definition::{
-    DefinitionCategory, ExceptHandlerDefinitionNodeRef, MatchPatternDefinitionNodeRef,
-    WithItemDefinitionNodeRef,
+    AssignmentKind, DefinitionCategory, ExceptHandlerDefinitionNodeRef,
+    MatchPatternDefinitionNodeRef, WithItemDefinitionNodeRef,
 };
 
 mod except_handlers;
@@ -47,7 +46,6 @@ pub(super) struct SemanticIndexBuilder<'db> {
     current_assignments: Vec<CurrentAssignment<'db>>,
     /// The match case we're currently visiting.
     current_match_case: Option<CurrentMatchCase<'db>>,
-
     /// Flow states at each `break` in the current loop.
     loop_break_states: Vec<FlowSnapshot>,
     /// Per-scope contexts regarding nested `try`/`except` statements
@@ -114,11 +112,9 @@ impl<'db> SemanticIndexBuilder<'db> {
     fn push_scope_with_parent(&mut self, node: NodeWithScopeRef, parent: Option<FileScopeId>) {
         let children_start = self.scopes.next_index() + 1;
 
-        #[allow(unsafe_code)]
         let scope = Scope {
             parent,
-            // SAFETY: `node` is guaranteed to be a child of `self.module`
-            node: unsafe { node.to_kind(self.module.clone()) },
+            kind: node.scope_kind(),
             descendents: children_start..children_start,
         };
         self.try_node_context_stack_manager.enter_nested_scope();
@@ -128,7 +124,15 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.use_def_maps.push(UseDefMapBuilder::new());
         let ast_id_scope = self.ast_ids.push(AstIdsBuilder::new());
 
-        let scope_id = ScopeId::new(self.db, self.file, file_scope_id, countme::Count::default());
+        #[allow(unsafe_code)]
+        // SAFETY: `node` is guaranteed to be a child of `self.module`
+        let scope_id = ScopeId::new(
+            self.db,
+            self.file,
+            file_scope_id,
+            unsafe { node.to_kind(self.module.clone()) },
+            countme::Count::default(),
+        );
 
         self.scope_ids_by_scope.push(scope_id);
         self.scopes_by_node.insert(node.node_key(), file_scope_id);
@@ -191,18 +195,14 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.current_symbol_table().mark_symbol_bound(id);
     }
 
-    fn mark_symbol_declared(&mut self, id: ScopedSymbolId) {
-        self.current_symbol_table().mark_symbol_declared(id);
-    }
-
     fn mark_symbol_used(&mut self, id: ScopedSymbolId) {
         self.current_symbol_table().mark_symbol_used(id);
     }
 
-    fn add_definition(
+    fn add_definition<'a>(
         &mut self,
         symbol: ScopedSymbolId,
-        definition_node: impl Into<DefinitionNodeRef<'db>>,
+        definition_node: impl Into<DefinitionNodeRef<'a>>,
     ) -> Definition<'db> {
         let definition_node: DefinitionNodeRef<'_> = definition_node.into();
         #[allow(unsafe_code)]
@@ -226,9 +226,6 @@ impl<'db> SemanticIndexBuilder<'db> {
         if category.is_binding() {
             self.mark_symbol_bound(symbol);
         }
-        if category.is_declaration() {
-            self.mark_symbol_declared(symbol);
-        }
 
         let use_def = self.current_use_def_map_mut();
         match category {
@@ -246,30 +243,12 @@ impl<'db> SemanticIndexBuilder<'db> {
         definition
     }
 
-    fn record_expression_constraint(&mut self, constraint_node: &ast::Expr) -> Constraint<'db> {
-        let constraint = self.build_constraint(constraint_node);
-        self.record_constraint(constraint);
-        constraint
-    }
-
-    fn record_constraint(&mut self, constraint: Constraint<'db>) {
-        self.current_use_def_map_mut().record_constraint(constraint);
-    }
-
-    fn build_constraint(&mut self, constraint_node: &Expr) -> Constraint<'db> {
+    fn add_expression_constraint(&mut self, constraint_node: &ast::Expr) -> Expression<'db> {
         let expression = self.add_standalone_expression(constraint_node);
-        Constraint {
-            node: ConstraintNode::Expression(expression),
-            is_positive: true,
-        }
-    }
-
-    fn record_negated_constraint(&mut self, constraint: Constraint<'db>) {
         self.current_use_def_map_mut()
-            .record_constraint(Constraint {
-                node: constraint.node,
-                is_positive: false,
-            });
+            .record_constraint(Constraint::Expression(expression));
+
+        expression
     }
 
     fn push_assignment(&mut self, assignment: CurrentAssignment<'db>) {
@@ -281,12 +260,8 @@ impl<'db> SemanticIndexBuilder<'db> {
         debug_assert!(popped_assignment.is_some());
     }
 
-    fn current_assignment(&self) -> Option<CurrentAssignment<'db>> {
-        self.current_assignments.last().copied()
-    }
-
-    fn current_assignment_mut(&mut self) -> Option<&mut CurrentAssignment<'db>> {
-        self.current_assignments.last_mut()
+    fn current_assignment(&self) -> Option<&CurrentAssignment<'db>> {
+        self.current_assignments.last()
     }
 
     fn add_pattern_constraint(
@@ -310,10 +285,7 @@ impl<'db> SemanticIndexBuilder<'db> {
             countme::Count::default(),
         );
         self.current_use_def_map_mut()
-            .record_constraint(Constraint {
-                node: ConstraintNode::Pattern(pattern_constraint),
-                is_positive: true,
-            });
+            .record_constraint(Constraint::Pattern(pattern_constraint));
         pattern_constraint
     }
 
@@ -366,7 +338,6 @@ impl<'db> SemanticIndexBuilder<'db> {
                 // note that the "bound" on the typevar is a totally different thing than whether
                 // or not a name is "bound" by a typevar declaration; the latter is always true.
                 self.mark_symbol_bound(symbol);
-                self.mark_symbol_declared(symbol);
                 if let Some(bounds) = bound {
                     self.visit_expr(bounds);
                 }
@@ -445,7 +416,7 @@ impl<'db> SemanticIndexBuilder<'db> {
         self.pop_scope();
     }
 
-    fn declare_parameter(&mut self, parameter: AnyParameterRef<'db>) {
+    fn declare_parameter(&mut self, parameter: AnyParameterRef) {
         let symbol = self.add_symbol(parameter.name().id().clone());
 
         let definition = self.add_definition(symbol, parameter);
@@ -619,48 +590,24 @@ where
             }
             ast::Stmt::Assign(node) => {
                 debug_assert_eq!(&self.current_assignments, &[]);
-
                 self.visit_expr(&node.value);
-                let value = self.add_standalone_expression(&node.value);
-
-                for target in &node.targets {
-                    // We only handle assignments to names and unpackings here, other targets like
-                    // attribute and subscript are handled separately as they don't create a new
-                    // definition.
-                    let current_assignment = match target {
-                        ast::Expr::List(_) | ast::Expr::Tuple(_) => {
-                            Some(CurrentAssignment::Assign {
-                                node,
-                                first: true,
-                                unpack: Some(Unpack::new(
-                                    self.db,
-                                    self.file,
-                                    self.current_scope(),
-                                    #[allow(unsafe_code)]
-                                    unsafe {
-                                        AstNodeRef::new(self.module.clone(), target)
-                                    },
-                                    value,
-                                    countme::Count::default(),
-                                )),
-                            })
-                        }
-                        ast::Expr::Name(_) => Some(CurrentAssignment::Assign {
-                            node,
-                            unpack: None,
-                            first: false,
-                        }),
+                self.add_standalone_expression(&node.value);
+                for (target_index, target) in node.targets.iter().enumerate() {
+                    let kind = match target {
+                        ast::Expr::List(_) | ast::Expr::Tuple(_) => Some(AssignmentKind::Sequence),
+                        ast::Expr::Name(_) => Some(AssignmentKind::Name),
                         _ => None,
                     };
-
-                    if let Some(current_assignment) = current_assignment {
-                        self.push_assignment(current_assignment);
+                    if let Some(kind) = kind {
+                        self.push_assignment(CurrentAssignment::Assign {
+                            assignment: node,
+                            target_index,
+                            kind,
+                        });
                     }
-
                     self.visit_expr(target);
-
-                    if current_assignment.is_some() {
-                        // Only need to pop in the case where we pushed something
+                    if kind.is_some() {
+                        // only need to pop in the case where we pushed something
                         self.pop_assignment();
                     }
                 }
@@ -692,8 +639,7 @@ where
             ast::Stmt::If(node) => {
                 self.visit_expr(&node.test);
                 let pre_if = self.flow_snapshot();
-                let constraint = self.record_expression_constraint(&node.test);
-                let mut constraints = vec![constraint];
+                self.add_expression_constraint(&node.test);
                 self.visit_body(&node.body);
                 let mut post_clauses: Vec<FlowSnapshot> = vec![];
                 for clause in &node.elif_else_clauses {
@@ -703,14 +649,7 @@ where
                     // we can only take an elif/else branch if none of the previous ones were
                     // taken, so the block entry state is always `pre_if`
                     self.flow_restore(pre_if.clone());
-                    for constraint in &constraints {
-                        self.record_negated_constraint(*constraint);
-                    }
-                    if let Some(elif_test) = &clause.test {
-                        self.visit_expr(elif_test);
-                        constraints.push(self.record_expression_constraint(elif_test));
-                    }
-                    self.visit_body(&clause.body);
+                    self.visit_elif_else_clause(clause);
                 }
                 for post_clause_state in post_clauses {
                     self.flow_merge(post_clause_state);
@@ -758,20 +697,12 @@ where
                     self.flow_merge(break_state);
                 }
             }
-            ast::Stmt::With(ast::StmtWith {
-                items,
-                body,
-                is_async,
-                ..
-            }) => {
+            ast::Stmt::With(ast::StmtWith { items, body, .. }) => {
                 for item in items {
                     self.visit_expr(&item.context_expr);
                     if let Some(optional_vars) = item.optional_vars.as_deref() {
                         self.add_standalone_expression(&item.context_expr);
-                        self.push_assignment(CurrentAssignment::WithItem {
-                            item,
-                            is_async: *is_async,
-                        });
+                        self.push_assignment(item.into());
                         self.visit_expr(optional_vars);
                         self.pop_assignment();
                     }
@@ -987,26 +918,20 @@ where
                 };
                 let symbol = self.add_symbol(id.clone());
 
-                if is_use {
-                    self.mark_symbol_used(symbol);
-                    let use_id = self.current_ast_ids().record_use(expr);
-                    self.current_use_def_map_mut().record_use(symbol, use_id);
-                }
-
                 if is_definition {
-                    match self.current_assignment() {
+                    match self.current_assignment().copied() {
                         Some(CurrentAssignment::Assign {
-                            node,
-                            first,
-                            unpack,
+                            assignment,
+                            target_index,
+                            kind,
                         }) => {
                             self.add_definition(
                                 symbol,
                                 AssignmentDefinitionNodeRef {
-                                    unpack,
-                                    value: &node.value,
+                                    assignment,
+                                    target_index,
                                     name: name_node,
-                                    first,
+                                    kind,
                                 },
                             );
                         }
@@ -1043,13 +968,12 @@ where
                                 },
                             );
                         }
-                        Some(CurrentAssignment::WithItem { item, is_async }) => {
+                        Some(CurrentAssignment::WithItem(with_item)) => {
                             self.add_definition(
                                 symbol,
                                 WithItemDefinitionNodeRef {
-                                    node: item,
+                                    node: with_item,
                                     target: name_node,
-                                    is_async,
                                 },
                             );
                         }
@@ -1057,9 +981,10 @@ where
                     }
                 }
 
-                if let Some(CurrentAssignment::Assign { first, .. }) = self.current_assignment_mut()
-                {
-                    *first = false;
+                if is_use {
+                    self.mark_symbol_used(symbol);
+                    let use_id = self.current_ast_ids().record_use(expr);
+                    self.current_use_def_map_mut().record_use(symbol, use_id);
                 }
 
                 walk_expr(self, expr);
@@ -1102,13 +1027,10 @@ where
                 // AST inspection, so we can't simplify here, need to record test expression for
                 // later checking)
                 self.visit_expr(test);
-                let constraint = self.record_expression_constraint(test);
                 let pre_if = self.flow_snapshot();
                 self.visit_expr(body);
                 let post_body = self.flow_snapshot();
                 self.flow_restore(pre_if);
-
-                self.record_negated_constraint(constraint);
                 self.visit_expr(orelse);
                 self.flow_merge(post_body);
             }
@@ -1162,33 +1084,6 @@ where
                     },
                 );
             }
-            ast::Expr::BoolOp(ast::ExprBoolOp {
-                values,
-                range: _,
-                op,
-            }) => {
-                // TODO detect statically known truthy or falsy values (via type inference, not naive
-                // AST inspection, so we can't simplify here, need to record test expression for
-                // later checking)
-                let mut snapshots = vec![];
-
-                for (index, value) in values.iter().enumerate() {
-                    self.visit_expr(value);
-                    // In the last value we don't need to take a snapshot nor add a constraint
-                    if index < values.len() - 1 {
-                        // Snapshot is taken after visiting the expression but before adding the constraint.
-                        snapshots.push(self.flow_snapshot());
-                        let constraint = self.build_constraint(value);
-                        match op {
-                            BoolOp::And => self.record_constraint(constraint),
-                            BoolOp::Or => self.record_negated_constraint(constraint),
-                        }
-                    }
-                }
-                for snapshot in snapshots {
-                    self.flow_merge(snapshot);
-                }
-            }
             _ => {
                 walk_expr(self, expr);
             }
@@ -1261,9 +1156,9 @@ where
 #[derive(Copy, Clone, Debug, PartialEq)]
 enum CurrentAssignment<'a> {
     Assign {
-        node: &'a ast::StmtAssign,
-        first: bool,
-        unpack: Option<Unpack<'a>>,
+        assignment: &'a ast::StmtAssign,
+        target_index: usize,
+        kind: AssignmentKind,
     },
     AnnAssign(&'a ast::StmtAnnAssign),
     AugAssign(&'a ast::StmtAugAssign),
@@ -1273,10 +1168,7 @@ enum CurrentAssignment<'a> {
         node: &'a ast::Comprehension,
         first: bool,
     },
-    WithItem {
-        item: &'a ast::WithItem,
-        is_async: bool,
-    },
+    WithItem(&'a ast::WithItem),
 }
 
 impl<'a> From<&'a ast::StmtAnnAssign> for CurrentAssignment<'a> {
@@ -1303,6 +1195,12 @@ impl<'a> From<&'a ast::ExprNamed> for CurrentAssignment<'a> {
     }
 }
 
+impl<'a> From<&'a ast::WithItem> for CurrentAssignment<'a> {
+    fn from(value: &'a ast::WithItem) -> Self {
+        Self::WithItem(value)
+    }
+}
+
 struct CurrentMatchCase<'a> {
     /// The pattern that's part of the current match case.
     pattern: &'a ast::Pattern,

crates/red_knot_python_semantic/src/semantic_index/constraint.rs

@@ -7,13 +7,7 @@ use crate::semantic_index::expression::Expression;
 use crate::semantic_index::symbol::{FileScopeId, ScopeId};
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub(crate) struct Constraint<'db> {
-    pub(crate) node: ConstraintNode<'db>,
-    pub(crate) is_positive: bool,
-}
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub(crate) enum ConstraintNode<'db> {
+pub(crate) enum Constraint<'db> {
     Expression(Expression<'db>),
     Pattern(PatternConstraint<'db>),
 }

crates/red_knot_python_semantic/src/semantic_index/definition.rs

@@ -6,22 +6,8 @@ use crate::ast_node_ref::AstNodeRef;
 use crate::module_resolver::file_to_module;
 use crate::node_key::NodeKey;
 use crate::semantic_index::symbol::{FileScopeId, ScopeId, ScopedSymbolId};
-use crate::unpack::Unpack;
 use crate::Db;
 
-/// A definition of a symbol.
-///
-/// ## Module-local type
-/// This type should not be used as part of any cross-module API because
-/// it holds a reference to the AST node. Range-offset changes
-/// then propagate through all usages, and deserialization requires
-/// reparsing the entire module.
-///
-/// E.g. don't use this type in:
-///
-/// * a return type of a cross-module query
-/// * a field of a type that is a return type of a cross-module query
-/// * an argument of a cross-module query
 #[salsa::tracked]
 pub struct Definition<'db> {
     /// The file in which the definition occurs.
@@ -38,7 +24,7 @@ pub struct Definition<'db> {
 
     #[no_eq]
     #[return_ref]
-    pub(crate) kind: DefinitionKind<'db>,
+    pub(crate) kind: DefinitionKind,
 
     #[no_eq]
     count: countme::Count<Definition<'static>>,
@@ -180,17 +166,16 @@ pub(crate) struct ImportFromDefinitionNodeRef<'a> {
 
 #[derive(Copy, Clone, Debug)]
 pub(crate) struct AssignmentDefinitionNodeRef<'a> {
-    pub(crate) unpack: Option<Unpack<'a>>,
-    pub(crate) value: &'a ast::Expr,
+    pub(crate) assignment: &'a ast::StmtAssign,
+    pub(crate) target_index: usize,
     pub(crate) name: &'a ast::ExprName,
-    pub(crate) first: bool,
+    pub(crate) kind: AssignmentKind,
 }
 
 #[derive(Copy, Clone, Debug)]
 pub(crate) struct WithItemDefinitionNodeRef<'a> {
     pub(crate) node: &'a ast::WithItem,
     pub(crate) target: &'a ast::ExprName,
-    pub(crate) is_async: bool,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -225,9 +210,9 @@ pub(crate) struct MatchPatternDefinitionNodeRef<'a> {
     pub(crate) index: u32,
 }
 
-impl<'db> DefinitionNodeRef<'db> {
+impl DefinitionNodeRef<'_> {
     #[allow(unsafe_code)]
-    pub(super) unsafe fn into_owned(self, parsed: ParsedModule) -> DefinitionKind<'db> {
+    pub(super) unsafe fn into_owned(self, parsed: ParsedModule) -> DefinitionKind {
         match self {
             DefinitionNodeRef::Import(alias) => {
                 DefinitionKind::Import(AstNodeRef::new(parsed, alias))
@@ -248,15 +233,15 @@ impl<'db> DefinitionNodeRef<'db> {
                 DefinitionKind::NamedExpression(AstNodeRef::new(parsed, named))
             }
             DefinitionNodeRef::Assignment(AssignmentDefinitionNodeRef {
-                unpack,
-                value,
+                assignment,
+                target_index,
                 name,
-                first,
+                kind,
             }) => DefinitionKind::Assignment(AssignmentDefinitionKind {
-                target: TargetKind::from(unpack),
-                value: AstNodeRef::new(parsed.clone(), value),
+                assignment: AstNodeRef::new(parsed.clone(), assignment),
+                target_index,
                 name: AstNodeRef::new(parsed, name),
-                first,
+                kind,
             }),
             DefinitionNodeRef::AnnotatedAssignment(assign) => {
                 DefinitionKind::AnnotatedAssignment(AstNodeRef::new(parsed, assign))
@@ -292,15 +277,12 @@ impl<'db> DefinitionNodeRef<'db> {
                     DefinitionKind::ParameterWithDefault(AstNodeRef::new(parsed, parameter))
                 }
             },
-            DefinitionNodeRef::WithItem(WithItemDefinitionNodeRef {
-                node,
-                target,
-                is_async,
-            }) => DefinitionKind::WithItem(WithItemDefinitionKind {
-                node: AstNodeRef::new(parsed.clone(), node),
-                target: AstNodeRef::new(parsed, target),
-                is_async,
-            }),
+            DefinitionNodeRef::WithItem(WithItemDefinitionNodeRef { node, target }) => {
+                DefinitionKind::WithItem(WithItemDefinitionKind {
+                    node: AstNodeRef::new(parsed.clone(), node),
+                    target: AstNodeRef::new(parsed, target),
+                })
+            }
             DefinitionNodeRef::MatchPattern(MatchPatternDefinitionNodeRef {
                 pattern,
                 identifier,
@@ -330,10 +312,10 @@ impl<'db> DefinitionNodeRef<'db> {
             Self::Class(node) => node.into(),
             Self::NamedExpression(node) => node.into(),
             Self::Assignment(AssignmentDefinitionNodeRef {
-                value: _,
-                unpack: _,
+                assignment: _,
+                target_index: _,
                 name,
-                first: _,
+                kind: _,
             }) => name.into(),
             Self::AnnotatedAssignment(node) => node.into(),
             Self::AugmentedAssignment(node) => node.into(),
@@ -347,11 +329,7 @@ impl<'db> DefinitionNodeRef<'db> {
                 ast::AnyParameterRef::Variadic(parameter) => parameter.into(),
                 ast::AnyParameterRef::NonVariadic(parameter) => parameter.into(),
             },
-            Self::WithItem(WithItemDefinitionNodeRef {
-                node: _,
-                target,
-                is_async: _,
-            }) => target.into(),
+            Self::WithItem(WithItemDefinitionNodeRef { node: _, target }) => target.into(),
             Self::MatchPattern(MatchPatternDefinitionNodeRef { identifier, .. }) => {
                 identifier.into()
             }
@@ -396,13 +374,13 @@ impl DefinitionCategory {
 }
 
 #[derive(Clone, Debug)]
-pub enum DefinitionKind<'db> {
+pub enum DefinitionKind {
     Import(AstNodeRef<ast::Alias>),
     ImportFrom(ImportFromDefinitionKind),
     Function(AstNodeRef<ast::StmtFunctionDef>),
     Class(AstNodeRef<ast::StmtClassDef>),
     NamedExpression(AstNodeRef<ast::ExprNamed>),
-    Assignment(AssignmentDefinitionKind<'db>),
+    Assignment(AssignmentDefinitionKind),
     AnnotatedAssignment(AstNodeRef<ast::StmtAnnAssign>),
     AugmentedAssignment(AstNodeRef<ast::StmtAugAssign>),
     For(ForStmtDefinitionKind),
@@ -414,7 +392,7 @@ pub enum DefinitionKind<'db> {
     ExceptHandler(ExceptHandlerDefinitionKind),
 }
 
-impl DefinitionKind<'_> {
+impl DefinitionKind {
     pub(crate) fn category(&self) -> DefinitionCategory {
         match self {
             // functions, classes, and imports always bind, and we consider them declarations
@@ -459,21 +437,6 @@ impl DefinitionKind<'_> {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
-pub(crate) enum TargetKind<'db> {
-    Sequence(Unpack<'db>),
-    Name,
-}
-
-impl<'db> From<Option<Unpack<'db>>> for TargetKind<'db> {
-    fn from(value: Option<Unpack<'db>>) -> Self {
-        match value {
-            Some(unpack) => TargetKind::Sequence(unpack),
-            None => TargetKind::Name,
-        }
-    }
-}
-
 #[derive(Clone, Debug)]
 #[allow(dead_code)]
 pub struct MatchPatternDefinitionKind {
@@ -535,36 +498,42 @@ impl ImportFromDefinitionKind {
 }
 
 #[derive(Clone, Debug)]
-pub struct AssignmentDefinitionKind<'db> {
-    target: TargetKind<'db>,
-    value: AstNodeRef<ast::Expr>,
+pub struct AssignmentDefinitionKind {
+    assignment: AstNodeRef<ast::StmtAssign>,
+    target_index: usize,
     name: AstNodeRef<ast::ExprName>,
-    first: bool,
+    kind: AssignmentKind,
 }
 
-impl<'db> AssignmentDefinitionKind<'db> {
-    pub(crate) fn target(&self) -> TargetKind<'db> {
-        self.target
+impl AssignmentDefinitionKind {
+    pub(crate) fn value(&self) -> &ast::Expr {
+        &self.assignment.node().value
     }
 
-    pub(crate) fn value(&self) -> &ast::Expr {
-        self.value.node()
+    pub(crate) fn target(&self) -> &ast::Expr {
+        &self.assignment.node().targets[self.target_index]
     }
 
     pub(crate) fn name(&self) -> &ast::ExprName {
         self.name.node()
     }
 
-    pub(crate) fn is_first(&self) -> bool {
-        self.first
+    pub(crate) fn kind(&self) -> AssignmentKind {
+        self.kind
     }
 }
 
+/// The kind of assignment target expression.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum AssignmentKind {
+    Sequence,
+    Name,
+}
+
 #[derive(Clone, Debug)]
 pub struct WithItemDefinitionKind {
     node: AstNodeRef<ast::WithItem>,
     target: AstNodeRef<ast::ExprName>,
-    is_async: bool,
 }
 
 impl WithItemDefinitionKind {
@@ -575,10 +544,6 @@ impl WithItemDefinitionKind {
     pub(crate) fn target(&self) -> &ast::ExprName {
         self.target.node()
     }
-
-    pub(crate) const fn is_async(&self) -> bool {
-        self.is_async
-    }
 }
 
 #[derive(Clone, Debug)]

crates/red_knot_python_semantic/src/semantic_index/expression.rs

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

crates/red_knot_python_semantic/src/semantic_index/symbol.rs

@@ -47,27 +47,17 @@ impl Symbol {
     pub fn is_bound(&self) -> bool {
         self.flags.contains(SymbolFlags::IS_BOUND)
     }
-
-    /// Is the symbol declared in its containing scope?
-    pub fn is_declared(&self) -> bool {
-        self.flags.contains(SymbolFlags::IS_DECLARED)
-    }
 }
 
 bitflags! {
-    /// Flags that can be queried to obtain information about a symbol in a given scope.
-    ///
-    /// See the doc-comment at the top of [`super::use_def`] for explanations of what it
-    /// means for a symbol to be *bound* as opposed to *declared*.
     #[derive(Copy, Clone, Debug, Eq, PartialEq)]
     struct SymbolFlags: u8 {
         const IS_USED         = 1 << 0;
-        const IS_BOUND        = 1 << 1;
-        const IS_DECLARED     = 1 << 2;
+        const IS_BOUND      = 1 << 1;
         /// TODO: This flag is not yet set by anything
-        const MARKED_GLOBAL   = 1 << 3;
+        const MARKED_GLOBAL   = 1 << 2;
         /// TODO: This flag is not yet set by anything
-        const MARKED_NONLOCAL = 1 << 4;
+        const MARKED_NONLOCAL = 1 << 3;
     }
 }
 
@@ -103,10 +93,14 @@ pub struct ScopedSymbolId;
 pub struct ScopeId<'db> {
     #[id]
     pub file: File,
-
     #[id]
     pub file_scope_id: FileScopeId,
 
+    /// The node that introduces this scope.
+    #[no_eq]
+    #[return_ref]
+    pub node: NodeWithScopeKind,
+
     #[no_eq]
     count: countme::Count<ScopeId<'static>>,
 }
@@ -127,14 +121,6 @@ impl<'db> ScopeId<'db> {
         )
     }
 
-    pub(crate) fn node(self, db: &dyn Db) -> &NodeWithScopeKind {
-        self.scope(db).node()
-    }
-
-    pub(crate) fn scope(self, db: &dyn Db) -> &Scope {
-        semantic_index(db, self.file(db)).scope(self.file_scope_id(db))
-    }
-
     #[cfg(test)]
     pub(crate) fn name(self, db: &'db dyn Db) -> &'db str {
         match self.node(db) {
@@ -173,10 +159,10 @@ impl FileScopeId {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Eq, PartialEq)]
 pub struct Scope {
     pub(super) parent: Option<FileScopeId>,
-    pub(super) node: NodeWithScopeKind,
+    pub(super) kind: ScopeKind,
     pub(super) descendents: Range<FileScopeId>,
 }
 
@@ -185,12 +171,8 @@ impl Scope {
         self.parent
     }
 
-    pub fn node(&self) -> &NodeWithScopeKind {
-        &self.node
-    }
-
     pub fn kind(&self) -> ScopeKind {
-        self.node().scope_kind()
+        self.kind
     }
 }
 
@@ -316,10 +298,6 @@ impl SymbolTableBuilder {
         self.table.symbols[id].insert_flags(SymbolFlags::IS_BOUND);
     }
 
-    pub(super) fn mark_symbol_declared(&mut self, id: ScopedSymbolId) {
-        self.table.symbols[id].insert_flags(SymbolFlags::IS_DECLARED);
-    }
-
     pub(super) fn mark_symbol_used(&mut self, id: ScopedSymbolId) {
         self.table.symbols[id].insert_flags(SymbolFlags::IS_USED);
     }
@@ -384,6 +362,21 @@ impl NodeWithScopeRef<'_> {
         }
     }
 
+    pub(super) fn scope_kind(self) -> ScopeKind {
+        match self {
+            NodeWithScopeRef::Module => ScopeKind::Module,
+            NodeWithScopeRef::Class(_) => ScopeKind::Class,
+            NodeWithScopeRef::Function(_) => ScopeKind::Function,
+            NodeWithScopeRef::Lambda(_) => ScopeKind::Function,
+            NodeWithScopeRef::FunctionTypeParameters(_)
+            | NodeWithScopeRef::ClassTypeParameters(_) => ScopeKind::Annotation,
+            NodeWithScopeRef::ListComprehension(_)
+            | NodeWithScopeRef::SetComprehension(_)
+            | NodeWithScopeRef::DictComprehension(_)
+            | NodeWithScopeRef::GeneratorExpression(_) => ScopeKind::Comprehension,
+        }
+    }
+
     pub(crate) fn node_key(self) -> NodeWithScopeKey {
         match self {
             NodeWithScopeRef::Module => NodeWithScopeKey::Module,
@@ -431,36 +424,6 @@ pub enum NodeWithScopeKind {
     GeneratorExpression(AstNodeRef<ast::ExprGenerator>),
 }
 
-impl NodeWithScopeKind {
-    pub(super) const fn scope_kind(&self) -> ScopeKind {
-        match self {
-            Self::Module => ScopeKind::Module,
-            Self::Class(_) => ScopeKind::Class,
-            Self::Function(_) => ScopeKind::Function,
-            Self::Lambda(_) => ScopeKind::Function,
-            Self::FunctionTypeParameters(_) | Self::ClassTypeParameters(_) => ScopeKind::Annotation,
-            Self::ListComprehension(_)
-            | Self::SetComprehension(_)
-            | Self::DictComprehension(_)
-            | Self::GeneratorExpression(_) => ScopeKind::Comprehension,
-        }
-    }
-
-    pub fn expect_class(&self) -> &ast::StmtClassDef {
-        match self {
-            Self::Class(class) => class.node(),
-            _ => panic!("expected class"),
-        }
-    }
-
-    pub fn expect_function(&self) -> &ast::StmtFunctionDef {
-        match self {
-            Self::Function(function) => function.node(),
-            _ => panic!("expected function"),
-        }
-    }
-}
-
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
 pub(crate) enum NodeWithScopeKey {
     Module,

crates/red_knot_python_semantic/src/semantic_index/use_def.rs

@@ -228,7 +228,6 @@ use self::symbol_state::{
 use crate::semantic_index::ast_ids::ScopedUseId;
 use crate::semantic_index::definition::Definition;
 use crate::semantic_index::symbol::ScopedSymbolId;
-use crate::symbol::Boundness;
 use ruff_index::IndexVec;
 use rustc_hash::FxHashMap;
 
@@ -275,12 +274,8 @@ impl<'db> UseDefMap<'db> {
         self.bindings_iterator(&self.bindings_by_use[use_id])
     }
 
-    pub(crate) fn use_boundness(&self, use_id: ScopedUseId) -> Boundness {
-        if self.bindings_by_use[use_id].may_be_unbound() {
-            Boundness::MayBeUnbound
-        } else {
-            Boundness::Bound
-        }
+    pub(crate) fn use_may_be_unbound(&self, use_id: ScopedUseId) -> bool {
+        self.bindings_by_use[use_id].may_be_unbound()
     }
 
     pub(crate) fn public_bindings(
@@ -290,12 +285,8 @@ impl<'db> UseDefMap<'db> {
         self.bindings_iterator(self.public_symbols[symbol].bindings())
     }
 
-    pub(crate) fn public_boundness(&self, symbol: ScopedSymbolId) -> Boundness {
-        if self.public_symbols[symbol].may_be_unbound() {
-            Boundness::MayBeUnbound
-        } else {
-            Boundness::Bound
-        }
+    pub(crate) fn public_may_be_unbound(&self, symbol: ScopedSymbolId) -> bool {
+        self.public_symbols[symbol].may_be_unbound()
     }
 
     pub(crate) fn bindings_at_declaration(

crates/red_knot_python_semantic/src/semantic_model.rs

@@ -8,7 +8,7 @@ use crate::module_name::ModuleName;
 use crate::module_resolver::{resolve_module, Module};
 use crate::semantic_index::ast_ids::HasScopedAstId;
 use crate::semantic_index::semantic_index;
-use crate::types::{binding_ty, infer_scope_types, Type};
+use crate::types::{binding_ty, global_symbol_ty, infer_scope_types, Type};
 use crate::Db;
 
 pub struct SemanticModel<'db> {
@@ -38,6 +38,10 @@ impl<'db> SemanticModel<'db> {
     pub fn resolve_module(&self, module_name: &ModuleName) -> Option<Module> {
         resolve_module(self.db, module_name)
     }
+
+    pub fn global_symbol_ty(&self, module: &Module, symbol_name: &str) -> Type<'db> {
+        global_symbol_ty(self.db, module.file(), symbol_name)
+    }
 }
 
 pub trait HasTy {

crates/red_knot_python_semantic/src/stdlib.rs

@@ -2,8 +2,7 @@ use crate::module_name::ModuleName;
 use crate::module_resolver::resolve_module;
 use crate::semantic_index::global_scope;
 use crate::semantic_index::symbol::ScopeId;
-use crate::symbol::Symbol;
-use crate::types::global_symbol;
+use crate::types::{global_symbol_ty, Type};
 use crate::Db;
 
 /// Enumeration of various core stdlib modules, for which we have dedicated Salsa queries.
@@ -13,7 +12,6 @@ enum CoreStdlibModule {
     Types,
     Typeshed,
     TypingExtensions,
-    Typing,
 }
 
 impl CoreStdlibModule {
@@ -21,7 +19,6 @@ impl CoreStdlibModule {
         let module_name = match self {
             Self::Builtins => "builtins",
             Self::Types => "types",
-            Self::Typing => "typing",
             Self::Typeshed => "_typeshed",
             Self::TypingExtensions => "typing_extensions",
         };
@@ -32,55 +29,54 @@ impl CoreStdlibModule {
 
 /// Lookup the type of `symbol` in a given core module
 ///
-/// Returns `Symbol::Unbound` if the given core module cannot be resolved for some reason
-fn core_module_symbol<'db>(
+/// Returns `Unbound` if the given core module cannot be resolved for some reason
+fn core_module_symbol_ty<'db>(
     db: &'db dyn Db,
     core_module: CoreStdlibModule,
     symbol: &str,
-) -> Symbol<'db> {
+) -> Type<'db> {
     resolve_module(db, &core_module.name())
-        .map(|module| global_symbol(db, module.file(), symbol))
-        .unwrap_or(Symbol::Unbound)
+        .map(|module| global_symbol_ty(db, module.file(), symbol))
+        .map(|ty| {
+            if ty.is_unbound() {
+                ty
+            } else {
+                ty.replace_unbound_with(db, Type::Never)
+            }
+        })
+        .unwrap_or(Type::Unbound)
 }
 
 /// Lookup the type of `symbol` in the builtins namespace.
 ///
-/// Returns `Symbol::Unbound` if the `builtins` module isn't available for some reason.
+/// Returns `Unbound` if the `builtins` module isn't available for some reason.
 #[inline]
-pub(crate) fn builtins_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
-    core_module_symbol(db, CoreStdlibModule::Builtins, symbol)
+pub(crate) fn builtins_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
+    core_module_symbol_ty(db, CoreStdlibModule::Builtins, symbol)
 }
 
 /// Lookup the type of `symbol` in the `types` module namespace.
 ///
-/// Returns `Symbol::Unbound` if the `types` module isn't available for some reason.
+/// Returns `Unbound` if the `types` module isn't available for some reason.
 #[inline]
-pub(crate) fn types_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
-    core_module_symbol(db, CoreStdlibModule::Types, symbol)
+pub(crate) fn types_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
+    core_module_symbol_ty(db, CoreStdlibModule::Types, symbol)
 }
 
-/// Lookup the type of `symbol` in the `typing` module namespace.
-///
-/// Returns `Symbol::Unbound` if the `typing` module isn't available for some reason.
-#[inline]
-#[allow(dead_code)] // currently only used in tests
-pub(crate) fn typing_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
-    core_module_symbol(db, CoreStdlibModule::Typing, symbol)
-}
 /// Lookup the type of `symbol` in the `_typeshed` module namespace.
 ///
-/// Returns `Symbol::Unbound` if the `_typeshed` module isn't available for some reason.
+/// Returns `Unbound` if the `_typeshed` module isn't available for some reason.
 #[inline]
-pub(crate) fn typeshed_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
-    core_module_symbol(db, CoreStdlibModule::Typeshed, symbol)
+pub(crate) fn typeshed_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
+    core_module_symbol_ty(db, CoreStdlibModule::Typeshed, symbol)
 }
 
 /// Lookup the type of `symbol` in the `typing_extensions` module namespace.
 ///
-/// Returns `Symbol::Unbound` if the `typing_extensions` module isn't available for some reason.
+/// Returns `Unbound` if the `typing_extensions` module isn't available for some reason.
 #[inline]
-pub(crate) fn typing_extensions_symbol<'db>(db: &'db dyn Db, symbol: &str) -> Symbol<'db> {
-    core_module_symbol(db, CoreStdlibModule::TypingExtensions, symbol)
+pub(crate) fn typing_extensions_symbol_ty<'db>(db: &'db dyn Db, symbol: &str) -> Type<'db> {
+    core_module_symbol_ty(db, CoreStdlibModule::TypingExtensions, symbol)
 }
 
 /// Get the scope of a core stdlib module.

crates/red_knot_python_semantic/src/symbol.rs

@@ -1,88 +0,0 @@
-use crate::{
-    types::{Type, UnionType},
-    Db,
-};
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) enum Boundness {
-    Bound,
-    MayBeUnbound,
-}
-
-/// The result of a symbol lookup, which can either be a (possibly unbound) type
-/// or a completely unbound symbol.
-///
-/// Consider this example:
-/// ```py
-/// bound = 1
-///
-/// if flag:
-///     maybe_unbound = 2
-/// ```
-///
-/// If we look up symbols in this scope, we would get the following results:
-/// ```rs
-/// bound:          Symbol::Type(Type::IntLiteral(1), Boundness::Bound),
-/// maybe_unbound:  Symbol::Type(Type::IntLiteral(2), Boundness::MayBeUnbound),
-/// non_existent:   Symbol::Unbound,
-/// ```
-#[derive(Debug, Clone, PartialEq)]
-pub(crate) enum Symbol<'db> {
-    Type(Type<'db>, Boundness),
-    Unbound,
-}
-
-impl<'db> Symbol<'db> {
-    pub(crate) fn is_unbound(&self) -> bool {
-        matches!(self, Symbol::Unbound)
-    }
-
-    pub(crate) fn may_be_unbound(&self) -> bool {
-        match self {
-            Symbol::Type(_, Boundness::MayBeUnbound) | Symbol::Unbound => true,
-            Symbol::Type(_, Boundness::Bound) => false,
-        }
-    }
-
-    pub(crate) fn unwrap_or_unknown(&self) -> Type<'db> {
-        match self {
-            Symbol::Type(ty, _) => *ty,
-            Symbol::Unbound => Type::Unknown,
-        }
-    }
-
-    pub(crate) fn as_type(&self) -> Option<Type<'db>> {
-        match self {
-            Symbol::Type(ty, _) => Some(*ty),
-            Symbol::Unbound => None,
-        }
-    }
-
-    #[cfg(test)]
-    #[track_caller]
-    pub(crate) fn expect_type(self) -> Type<'db> {
-        self.as_type()
-            .expect("Expected a (possibly unbound) type, not an unbound symbol")
-    }
-
-    #[must_use]
-    pub(crate) fn replace_unbound_with(
-        self,
-        db: &'db dyn Db,
-        replacement: &Symbol<'db>,
-    ) -> Symbol<'db> {
-        match replacement {
-            Symbol::Type(replacement, _) => Symbol::Type(
-                match self {
-                    Symbol::Type(ty, Boundness::Bound) => ty,
-                    Symbol::Type(ty, Boundness::MayBeUnbound) => {
-                        UnionType::from_elements(db, [*replacement, ty])
-                    }
-                    Symbol::Unbound => *replacement,
-                },
-                Boundness::Bound,
-            ),
-            Symbol::Unbound => self,
-        }
-    }
-}

crates/red_knot_python_semantic/src/types/builder.rs

@@ -25,11 +25,12 @@
 //!   * No type in an intersection can be a supertype of any other type in the intersection (just
 //!     eliminate the supertype from the intersection).
 //!   * An intersection containing two non-overlapping types should simplify to [`Type::Never`].
-
-use crate::types::{InstanceType, IntersectionType, KnownClass, Type, UnionType};
+use crate::types::{IntersectionType, Type, UnionType};
 use crate::{Db, FxOrderSet};
 use smallvec::SmallVec;
 
+use super::KnownClass;
+
 pub(crate) struct UnionBuilder<'db> {
     elements: Vec<Type<'db>>,
     db: &'db dyn Db,
@@ -79,6 +80,7 @@ impl<'db> UnionBuilder<'db> {
                         to_remove.push(index);
                     }
                 }
+
                 match to_remove[..] {
                     [] => self.elements.push(to_add),
                     [index] => self.elements[index] = to_add,
@@ -101,6 +103,7 @@ impl<'db> UnionBuilder<'db> {
                 }
             }
         }
+
         self
     }
 
@@ -170,37 +173,14 @@ impl<'db> IntersectionBuilder<'db> {
     pub(crate) fn add_negative(mut self, ty: Type<'db>) -> Self {
         // See comments above in `add_positive`; this is just the negated version.
         if let Type::Union(union) = ty {
-            for elem in union.elements(self.db) {
-                self = self.add_negative(*elem);
-            }
-            self
-        } else if let Type::Intersection(intersection) = ty {
-            // (A | B) & ~(C & ~D)
-            // -> (A | B) & (~C | D)
-            // -> ((A | B) & ~C) | ((A | B) & D)
-            // i.e. if we have an intersection of positive constraints C
-            // and negative constraints D, then our new intersection
-            // is (existing & ~C) | (existing & D)
-
-            let positive_side = intersection
-                .positive(self.db)
+            union
+                .elements(self.db)
                 .iter()
-                // we negate all the positive constraints while distributing
-                .map(|elem| self.clone().add_negative(*elem));
-
-            let negative_side = intersection
-                .negative(self.db)
-                .iter()
-                // all negative constraints end up becoming positive constraints
-                .map(|elem| self.clone().add_positive(*elem));
-
-            positive_side.chain(negative_side).fold(
-                IntersectionBuilder::empty(self.db),
-                |mut builder, sub| {
+                .map(|elem| self.clone().add_negative(*elem))
+                .fold(IntersectionBuilder::empty(self.db), |mut builder, sub| {
                     builder.intersections.extend(sub.intersections);
                     builder
-                },
-            )
+                })
         } else {
             for inner in &mut self.intersections {
                 inner.add_negative(self.db, ty);
@@ -246,8 +226,8 @@ impl<'db> InnerIntersectionBuilder<'db> {
             }
         } else {
             // ~Literal[True] & bool = Literal[False]
-            if let Type::Instance(InstanceType { class }) = new_positive {
-                if class.is_known(db, KnownClass::Bool) {
+            if let Type::Instance(class_type) = new_positive {
+                if class_type.is_known(db, KnownClass::Bool) {
                     if let Some(&Type::BooleanLiteral(value)) = self
                         .negative
                         .iter()
@@ -313,11 +293,12 @@ impl<'db> InnerIntersectionBuilder<'db> {
                     self.add_positive(db, *neg);
                 }
             }
+            Type::Unbound => {}
             ty @ (Type::Any | Type::Unknown | Type::Todo) => {
                 // Adding any of these types to the negative side of an intersection
                 // is equivalent to adding it to the positive side. We do this to
                 // simplify the representation.
-                self.add_positive(db, ty);
+                self.positive.insert(ty);
             }
             // ~Literal[True] & bool = Literal[False]
             Type::BooleanLiteral(bool)
@@ -363,7 +344,15 @@ impl<'db> InnerIntersectionBuilder<'db> {
         }
     }
 
+    fn simplify_unbound(&mut self) {
+        if self.positive.contains(&Type::Unbound) {
+            self.positive.retain(Type::is_unbound);
+            self.negative.clear();
+        }
+    }
+
     fn build(mut self, db: &'db dyn Db) -> Type<'db> {
+        self.simplify_unbound();
         match (self.positive.len(), self.negative.len()) {
             (0, 0) => KnownClass::Object.to_instance(db),
             (1, 0) => self.positive[0],
@@ -382,10 +371,8 @@ mod tests {
     use crate::db::tests::TestDb;
     use crate::program::{Program, SearchPathSettings};
     use crate::python_version::PythonVersion;
-    use crate::stdlib::typing_symbol;
-    use crate::types::{global_symbol, KnownClass, StringLiteralType, UnionBuilder};
+    use crate::types::{KnownClass, StringLiteralType, UnionBuilder};
     use crate::ProgramSettings;
-    use ruff_db::files::system_path_to_file;
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
     use test_case::test_case;
 
@@ -574,38 +561,18 @@ mod tests {
         let ta = Type::Any;
         let t1 = Type::IntLiteral(1);
         let t2 = KnownClass::Int.to_instance(&db);
-        // i0 = Any & ~Literal[1]
         let i0 = IntersectionBuilder::new(&db)
             .add_positive(ta)
             .add_negative(t1)
             .build();
-        // ta_not_i0 = int & ~(Any & ~Literal[1])
-        // -> int & (~Any  | Literal[1])
-        // (~Any is equivalent to Any)
-        // -> (int & Any) | (int & Literal[1])
-        // -> (int & Any) | Literal[1]
-        let ta_not_i0 = IntersectionBuilder::new(&db)
+        let intersection = IntersectionBuilder::new(&db)
             .add_positive(t2)
             .add_negative(i0)
-            .build();
+            .build()
+            .expect_intersection();
 
-        assert_eq!(ta_not_i0.display(&db).to_string(), "int & Any | Literal[1]");
-    }
-
-    #[test]
-    fn build_intersection_simplify_negative_any() {
-        let db = setup_db();
-
-        let ty = IntersectionBuilder::new(&db)
-            .add_negative(Type::Any)
-            .build();
-        assert_eq!(ty, Type::Any);
-
-        let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::Never)
-            .add_negative(Type::Any)
-            .build();
-        assert_eq!(ty, Type::Never);
+        assert_eq!(intersection.pos_vec(&db), &[ta, t1]);
+        assert_eq!(intersection.neg_vec(&db), &[]);
     }
 
     #[test]
@@ -628,69 +595,12 @@ mod tests {
         assert_eq!(i1.pos_vec(&db), &[ta, t1]);
     }
 
-    #[test]
-    fn intersection_negation_distributes_over_union() {
-        let db = setup_db();
-        let st = typing_symbol(&db, "Sized").expect_type().to_instance(&db);
-        let ht = typing_symbol(&db, "Hashable")
-            .expect_type()
-            .to_instance(&db);
-        // sh_t: Sized & Hashable
-        let sh_t = IntersectionBuilder::new(&db)
-            .add_positive(st)
-            .add_positive(ht)
-            .build()
-            .expect_intersection();
-        assert_eq!(sh_t.pos_vec(&db), &[st, ht]);
-        assert_eq!(sh_t.neg_vec(&db), &[]);
-
-        // ~sh_t => ~Sized | ~Hashable
-        let not_s_h_t = IntersectionBuilder::new(&db)
-            .add_negative(Type::Intersection(sh_t))
-            .build()
-            .expect_union();
-
-        // should have as elements: (~Sized),(~Hashable)
-        let not_st = st.negate(&db);
-        let not_ht = ht.negate(&db);
-        assert_eq!(not_s_h_t.elements(&db), &[not_st, not_ht]);
-    }
-
-    #[test]
-    fn mixed_intersection_negation_distributes_over_union() {
-        let db = setup_db();
-        let it = KnownClass::Int.to_instance(&db);
-        let st = typing_symbol(&db, "Sized").expect_type().to_instance(&db);
-        let ht = typing_symbol(&db, "Hashable")
-            .expect_type()
-            .to_instance(&db);
-        // s_not_h_t: Sized & ~Hashable
-        let s_not_h_t = IntersectionBuilder::new(&db)
-            .add_positive(st)
-            .add_negative(ht)
-            .build()
-            .expect_intersection();
-        assert_eq!(s_not_h_t.pos_vec(&db), &[st]);
-        assert_eq!(s_not_h_t.neg_vec(&db), &[ht]);
-
-        // let's build int & ~(Sized & ~Hashable)
-        let tt = IntersectionBuilder::new(&db)
-            .add_positive(it)
-            .add_negative(Type::Intersection(s_not_h_t))
-            .build();
-
-        // int & ~(Sized & ~Hashable)
-        // -> int & (~Sized | Hashable)
-        // -> (int & ~Sized) | (int & Hashable)
-        assert_eq!(tt.display(&db).to_string(), "int & ~Sized | int & Hashable");
-    }
-
     #[test]
     fn build_intersection_self_negation() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
-            .add_negative(Type::none(&db))
+            .add_positive(Type::None)
+            .add_negative(Type::None)
             .build();
 
         assert_eq!(ty, Type::Never);
@@ -700,18 +610,18 @@ mod tests {
     fn build_intersection_simplify_negative_never() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
+            .add_positive(Type::None)
             .add_negative(Type::Never)
             .build();
 
-        assert_eq!(ty, Type::none(&db));
+        assert_eq!(ty, Type::None);
     }
 
     #[test]
     fn build_intersection_simplify_positive_never() {
         let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
-            .add_positive(Type::none(&db))
+            .add_positive(Type::None)
             .add_positive(Type::Never)
             .build();
 
@@ -719,41 +629,42 @@ mod tests {
     }
 
     #[test]
-    fn build_intersection_simplify_negative_none() {
+    fn build_intersection_simplify_positive_unbound() {
         let db = setup_db();
-
         let ty = IntersectionBuilder::new(&db)
-            .add_negative(Type::none(&db))
+            .add_positive(Type::Unbound)
             .add_positive(Type::IntLiteral(1))
             .build();
-        assert_eq!(ty, Type::IntLiteral(1));
 
+        assert_eq!(ty, Type::Unbound);
+    }
+
+    #[test]
+    fn build_intersection_simplify_negative_unbound() {
+        let db = setup_db();
         let ty = IntersectionBuilder::new(&db)
+            .add_negative(Type::Unbound)
             .add_positive(Type::IntLiteral(1))
-            .add_negative(Type::none(&db))
             .build();
+
         assert_eq!(ty, Type::IntLiteral(1));
     }
 
     #[test]
-    fn build_negative_union_de_morgan() {
+    fn build_intersection_simplify_negative_none() {
         let db = setup_db();
 
-        let union = UnionBuilder::new(&db)
-            .add(Type::IntLiteral(1))
-            .add(Type::IntLiteral(2))
+        let ty = IntersectionBuilder::new(&db)
+            .add_negative(Type::None)
+            .add_positive(Type::IntLiteral(1))
             .build();
-        assert_eq!(union.display(&db).to_string(), "Literal[1, 2]");
+        assert_eq!(ty, Type::IntLiteral(1));
 
-        let ty = IntersectionBuilder::new(&db).add_negative(union).build();
-
-        let expected = IntersectionBuilder::new(&db)
-            .add_negative(Type::IntLiteral(1))
-            .add_negative(Type::IntLiteral(2))
+        let ty = IntersectionBuilder::new(&db)
+            .add_positive(Type::IntLiteral(1))
+            .add_negative(Type::None)
             .build();
-
-        assert_eq!(ty.display(&db).to_string(), "~Literal[1] & ~Literal[2]");
-        assert_eq!(ty, expected);
+        assert_eq!(ty, Type::IntLiteral(1));
     }
 
     #[test]
@@ -889,7 +800,7 @@ mod tests {
         let db = setup_db();
 
         let t1 = Type::IntLiteral(1);
-        let t2 = Type::none(&db);
+        let t2 = Type::None;
 
         let ty = IntersectionBuilder::new(&db)
             .add_positive(t1)
@@ -1007,66 +918,4 @@ mod tests {
             .build();
         assert_eq!(result, ty);
     }
-
-    #[test]
-    fn build_intersection_of_two_unions_simplify() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/module.py",
-            "
-            class A: ...
-            class B: ...
-            a = A()
-            b = B()
-        ",
-        )
-        .unwrap();
-
-        let file = system_path_to_file(&db, "src/module.py").expect("file to exist");
-
-        let a = global_symbol(&db, file, "a").expect_type();
-        let b = global_symbol(&db, file, "b").expect_type();
-        let union = UnionBuilder::new(&db).add(a).add(b).build();
-        assert_eq!(union.display(&db).to_string(), "A | B");
-        let reversed_union = UnionBuilder::new(&db).add(b).add(a).build();
-        assert_eq!(reversed_union.display(&db).to_string(), "B | A");
-        let intersection = IntersectionBuilder::new(&db)
-            .add_positive(union)
-            .add_positive(reversed_union)
-            .build();
-        assert_eq!(intersection.display(&db).to_string(), "B | A");
-    }
-
-    #[test]
-    fn build_union_of_two_intersections_simplify() {
-        let mut db = setup_db();
-        db.write_dedented(
-            "/src/module.py",
-            "
-            class A: ...
-            class B: ...
-            a = A()
-            b = B()
-        ",
-        )
-        .unwrap();
-
-        let file = system_path_to_file(&db, "src/module.py").expect("file to exist");
-
-        let a = global_symbol(&db, file, "a").expect_type();
-        let b = global_symbol(&db, file, "b").expect_type();
-        let intersection = IntersectionBuilder::new(&db)
-            .add_positive(a)
-            .add_positive(b)
-            .build();
-        let reversed_intersection = IntersectionBuilder::new(&db)
-            .add_positive(b)
-            .add_positive(a)
-            .build();
-        let union = UnionBuilder::new(&db)
-            .add(intersection)
-            .add(reversed_intersection)
-            .build();
-        assert_eq!(union.display(&db).to_string(), "A & B");
-    }
 }

crates/red_knot_python_semantic/src/types/diagnostic.rs

@@ -1,15 +1,10 @@
-use crate::types::{ClassLiteralType, Type};
-use crate::Db;
-use ruff_db::diagnostic::{Diagnostic, Severity};
 use ruff_db::files::File;
-use ruff_python_ast::{self as ast, AnyNodeRef};
 use ruff_text_size::{Ranged, TextRange};
-use std::borrow::Cow;
 use std::fmt::Formatter;
 use std::ops::Deref;
 use std::sync::Arc;
 
-#[derive(Debug, Eq, PartialEq, Clone)]
+#[derive(Debug, Eq, PartialEq)]
 pub struct TypeCheckDiagnostic {
     // TODO: Don't use string keys for rules
     pub(super) rule: String,
@@ -32,28 +27,6 @@ impl TypeCheckDiagnostic {
     }
 }
 
-impl Diagnostic for TypeCheckDiagnostic {
-    fn rule(&self) -> &str {
-        TypeCheckDiagnostic::rule(self)
-    }
-
-    fn message(&self) -> Cow<str> {
-        TypeCheckDiagnostic::message(self).into()
-    }
-
-    fn file(&self) -> File {
-        TypeCheckDiagnostic::file(self)
-    }
-
-    fn range(&self) -> Option<TextRange> {
-        Some(Ranged::range(self))
-    }
-
-    fn severity(&self) -> Severity {
-        Severity::Error
-    }
-}
-
 impl Ranged for TypeCheckDiagnostic {
     fn range(&self) -> TextRange {
         self.range
@@ -136,191 +109,3 @@ impl<'a> IntoIterator for &'a TypeCheckDiagnostics {
         self.inner.iter()
     }
 }
-
-pub(super) struct TypeCheckDiagnosticsBuilder<'db> {
-    db: &'db dyn Db,
-    file: File,
-    diagnostics: TypeCheckDiagnostics,
-}
-
-impl<'db> TypeCheckDiagnosticsBuilder<'db> {
-    pub(super) fn new(db: &'db dyn Db, file: File) -> Self {
-        Self {
-            db,
-            file,
-            diagnostics: TypeCheckDiagnostics::new(),
-        }
-    }
-
-    /// Emit a diagnostic declaring that the object represented by `node` is not iterable
-    pub(super) fn add_not_iterable(&mut self, node: AnyNodeRef, not_iterable_ty: Type<'db>) {
-        self.add(
-            node,
-            "not-iterable",
-            format_args!(
-                "Object of type `{}` is not iterable",
-                not_iterable_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that the object represented by `node` is not iterable
-    /// because its `__iter__` method is possibly unbound.
-    pub(super) fn add_not_iterable_possibly_unbound(
-        &mut self,
-        node: AnyNodeRef,
-        element_ty: Type<'db>,
-    ) {
-        self.add(
-            node,
-            "not-iterable",
-            format_args!(
-                "Object of type `{}` is not iterable because its `__iter__` method is possibly unbound",
-                element_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that an index is out of bounds for a tuple.
-    pub(super) fn add_index_out_of_bounds(
-        &mut self,
-        kind: &'static str,
-        node: AnyNodeRef,
-        tuple_ty: Type<'db>,
-        length: usize,
-        index: i64,
-    ) {
-        self.add(
-            node,
-            "index-out-of-bounds",
-            format_args!(
-                "Index {index} is out of bounds for {kind} `{}` with length {length}",
-                tuple_ty.display(self.db)
-            ),
-        );
-    }
-
-    /// Emit a diagnostic declaring that a type does not support subscripting.
-    pub(super) fn add_non_subscriptable(
-        &mut self,
-        node: AnyNodeRef,
-        non_subscriptable_ty: Type<'db>,
-        method: &str,
-    ) {
-        self.add(
-            node,
-            "non-subscriptable",
-            format_args!(
-                "Cannot subscript object of type `{}` with no `{method}` method",
-                non_subscriptable_ty.display(self.db)
-            ),
-        );
-    }
-
-    pub(super) fn add_unresolved_module(
-        &mut self,
-        import_node: impl Into<AnyNodeRef<'db>>,
-        level: u32,
-        module: Option<&str>,
-    ) {
-        self.add(
-            import_node.into(),
-            "unresolved-import",
-            format_args!(
-                "Cannot resolve import `{}{}`",
-                ".".repeat(level as usize),
-                module.unwrap_or_default()
-            ),
-        );
-    }
-
-    pub(super) fn add_slice_step_size_zero(&mut self, node: AnyNodeRef) {
-        self.add(
-            node,
-            "zero-stepsize-in-slice",
-            format_args!("Slice step size can not be zero"),
-        );
-    }
-
-    pub(super) fn add_invalid_assignment(
-        &mut self,
-        node: AnyNodeRef,
-        declared_ty: Type<'db>,
-        assigned_ty: Type<'db>,
-    ) {
-        match declared_ty {
-            Type::ClassLiteral(ClassLiteralType { class }) => {
-                self.add(node, "invalid-assignment", format_args!(
-                        "Implicit shadowing of class `{}`; annotate to make it explicit if this is intentional",
-                        class.name(self.db)));
-            }
-            Type::FunctionLiteral(function) => {
-                self.add(node, "invalid-assignment", format_args!(
-                        "Implicit shadowing of function `{}`; annotate to make it explicit if this is intentional",
-                        function.name(self.db)));
-            }
-            _ => {
-                self.add(
-                    node,
-                    "invalid-assignment",
-                    format_args!(
-                        "Object of type `{}` is not assignable to `{}`",
-                        assigned_ty.display(self.db),
-                        declared_ty.display(self.db),
-                    ),
-                );
-            }
-        }
-    }
-
-    pub(super) fn add_possibly_unresolved_reference(&mut self, expr_name_node: &ast::ExprName) {
-        let ast::ExprName { id, .. } = expr_name_node;
-
-        self.add(
-            expr_name_node.into(),
-            "possibly-unresolved-reference",
-            format_args!("Name `{id}` used when possibly not defined"),
-        );
-    }
-
-    pub(super) fn add_unresolved_reference(&mut self, expr_name_node: &ast::ExprName) {
-        let ast::ExprName { id, .. } = expr_name_node;
-
-        self.add(
-            expr_name_node.into(),
-            "unresolved-reference",
-            format_args!("Name `{id}` used when not defined"),
-        );
-    }
-
-    /// Adds a new diagnostic.
-    ///
-    /// The diagnostic does not get added if the rule isn't enabled for this file.
-    pub(super) fn add(&mut self, node: AnyNodeRef, rule: &str, message: std::fmt::Arguments) {
-        if !self.db.is_file_open(self.file) {
-            return;
-        }
-
-        // TODO: Don't emit the diagnostic if:
-        // * The enclosing node contains any syntax errors
-        // * The rule is disabled for this file. We probably want to introduce a new query that
-        //   returns a rule selector for a given file that respects the package's settings,
-        //   any global pragma comments in the file, and any per-file-ignores.
-
-        self.diagnostics.push(TypeCheckDiagnostic {
-            file: self.file,
-            rule: rule.to_string(),
-            message: message.to_string(),
-            range: node.range(),
-        });
-    }
-
-    pub(super) fn extend(&mut self, diagnostics: &TypeCheckDiagnostics) {
-        self.diagnostics.extend(diagnostics);
-    }
-
-    pub(super) fn finish(mut self) -> TypeCheckDiagnostics {
-        self.diagnostics.shrink_to_fit();
-        self.diagnostics
-    }
-}

crates/red_knot_python_semantic/src/types/display.rs

@@ -6,9 +6,7 @@ use ruff_db::display::FormatterJoinExtension;
 use ruff_python_ast::str::Quote;
 use ruff_python_literal::escape::AsciiEscape;
 
-use crate::types::{
-    ClassLiteralType, InstanceType, IntersectionType, KnownClass, SubclassOfType, Type, UnionType,
-};
+use crate::types::{IntersectionType, Type, UnionType};
 use crate::Db;
 use rustc_hash::FxHashMap;
 
@@ -66,11 +64,8 @@ impl Display for DisplayRepresentation<'_> {
             Type::Any => f.write_str("Any"),
             Type::Never => f.write_str("Never"),
             Type::Unknown => f.write_str("Unknown"),
-            Type::Instance(InstanceType { class })
-                if class.is_known(self.db, KnownClass::NoneType) =>
-            {
-                f.write_str("None")
-            }
+            Type::Unbound => f.write_str("Unbound"),
+            Type::None => f.write_str("None"),
             // `[Type::Todo]`'s display should be explicit that is not a valid display of
             // any other type
             Type::Todo => f.write_str("@Todo"),
@@ -78,12 +73,8 @@ impl Display for DisplayRepresentation<'_> {
                 write!(f, "<module '{:?}'>", file.path(self.db))
             }
             // TODO functions and classes should display using a fully qualified name
-            Type::ClassLiteral(ClassLiteralType { class }) => f.write_str(class.name(self.db)),
-            Type::SubclassOf(SubclassOfType { class }) => {
-                write!(f, "type[{}]", class.name(self.db))
-            }
-            Type::Instance(InstanceType { class }) => f.write_str(class.name(self.db)),
-            Type::KnownInstance(known_instance) => f.write_str(known_instance.as_str()),
+            Type::ClassLiteral(class) => f.write_str(class.name(self.db)),
+            Type::Instance(class) => f.write_str(class.name(self.db)),
             Type::FunctionLiteral(function) => f.write_str(function.name(self.db)),
             Type::Union(union) => union.display(self.db).fmt(f),
             Type::Intersection(intersection) => intersection.display(self.db).fmt(f),
@@ -99,28 +90,6 @@ impl Display for DisplayRepresentation<'_> {
 
                 escape.bytes_repr().write(f)
             }
-            Type::SliceLiteral(slice) => {
-                f.write_str("slice[")?;
-                if let Some(start) = slice.start(self.db) {
-                    write!(f, "Literal[{start}]")?;
-                } else {
-                    f.write_str("None")?;
-                }
-
-                f.write_str(", ")?;
-
-                if let Some(stop) = slice.stop(self.db) {
-                    write!(f, "Literal[{stop}]")?;
-                } else {
-                    f.write_str("None")?;
-                }
-
-                if let Some(step) = slice.step(self.db) {
-                    write!(f, ", Literal[{step}]")?;
-                }
-
-                f.write_str("]")
-            }
             Type::Tuple(tuple) => {
                 f.write_str("tuple[")?;
                 let elements = tuple.elements(self.db);
@@ -332,9 +301,7 @@ mod tests {
     use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
 
     use crate::db::tests::TestDb;
-    use crate::types::{
-        global_symbol, BytesLiteralType, SliceLiteralType, StringLiteralType, Type, UnionType,
-    };
+    use crate::types::{global_symbol_ty, BytesLiteralType, StringLiteralType, Type, UnionType};
     use crate::{Program, ProgramSettings, PythonVersion, SearchPathSettings};
 
     fn setup_db() -> TestDb {
@@ -379,18 +346,18 @@ mod tests {
         let union_elements = &[
             Type::Unknown,
             Type::IntLiteral(-1),
-            global_symbol(&db, mod_file, "A").expect_type(),
+            global_symbol_ty(&db, mod_file, "A"),
             Type::StringLiteral(StringLiteralType::new(&db, "A")),
             Type::BytesLiteral(BytesLiteralType::new(&db, [0u8].as_slice())),
             Type::BytesLiteral(BytesLiteralType::new(&db, [7u8].as_slice())),
             Type::IntLiteral(0),
             Type::IntLiteral(1),
             Type::StringLiteral(StringLiteralType::new(&db, "B")),
-            global_symbol(&db, mod_file, "foo").expect_type(),
-            global_symbol(&db, mod_file, "bar").expect_type(),
-            global_symbol(&db, mod_file, "B").expect_type(),
+            global_symbol_ty(&db, mod_file, "foo"),
+            global_symbol_ty(&db, mod_file, "bar"),
+            global_symbol_ty(&db, mod_file, "B"),
             Type::BooleanLiteral(true),
-            Type::none(&db),
+            Type::None,
         ];
         let union = UnionType::from_elements(&db, union_elements).expect_union();
         let display = format!("{}", union.display(&db));
@@ -409,46 +376,4 @@ mod tests {
         );
         Ok(())
     }
-
-    #[test]
-    fn test_slice_literal_display() {
-        let db = setup_db();
-
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, None, None, None))
-                .display(&db)
-                .to_string(),
-            "slice[None, None]"
-        );
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, Some(1), None, None))
-                .display(&db)
-                .to_string(),
-            "slice[Literal[1], None]"
-        );
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, None, Some(2), None))
-                .display(&db)
-                .to_string(),
-            "slice[None, Literal[2]]"
-        );
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, Some(1), Some(5), None))
-                .display(&db)
-                .to_string(),
-            "slice[Literal[1], Literal[5]]"
-        );
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, Some(1), Some(5), Some(2)))
-                .display(&db)
-                .to_string(),
-            "slice[Literal[1], Literal[5], Literal[2]]"
-        );
-        assert_eq!(
-            Type::SliceLiteral(SliceLiteralType::new(&db, None, None, Some(2)))
-                .display(&db)
-                .to_string(),
-            "slice[None, None, Literal[2]]"
-        );
-    }
 }

crates/red_knot_python_semantic/src/types/mro.rs

@@ -1,505 +0,0 @@
-use std::collections::VecDeque;
-use std::ops::Deref;
-
-use indexmap::IndexSet;
-use itertools::Either;
-use rustc_hash::FxHashSet;
-
-use super::{Class, ClassLiteralType, KnownClass, KnownInstanceType, Type};
-use crate::Db;
-
-/// The inferred method resolution order of a given class.
-///
-/// See [`Class::iter_mro`] for more details.
-#[derive(PartialEq, Eq, Clone, Debug)]
-pub(super) struct Mro<'db>(Box<[ClassBase<'db>]>);
-
-impl<'db> Mro<'db> {
-    /// Attempt to resolve the MRO of a given class
-    ///
-    /// In the event that a possible list of bases would (or could) lead to a
-    /// `TypeError` being raised at runtime due to an unresolvable MRO, we infer
-    /// the MRO of the class as being `[<the class in question>, Unknown, object]`.
-    /// This seems most likely to reduce the possibility of cascading errors
-    /// elsewhere.
-    ///
-    /// (We emit a diagnostic warning about the runtime `TypeError` in
-    /// [`super::infer::TypeInferenceBuilder::infer_region_scope`].)
-    pub(super) fn of_class(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroError<'db>> {
-        Self::of_class_impl(db, class).map_err(|error_kind| {
-            let fallback_mro = Self::from([
-                ClassBase::Class(class),
-                ClassBase::Unknown,
-                ClassBase::object(db),
-            ]);
-            MroError {
-                kind: error_kind,
-                fallback_mro,
-            }
-        })
-    }
-
-    fn of_class_impl(db: &'db dyn Db, class: Class<'db>) -> Result<Self, MroErrorKind<'db>> {
-        let class_bases = class.explicit_bases(db);
-
-        match class_bases {
-            // `builtins.object` is the special case:
-            // the only class in Python that has an MRO with length <2
-            [] if class.is_known(db, KnownClass::Object) => {
-                Ok(Self::from([ClassBase::Class(class)]))
-            }
-
-            // All other classes in Python have an MRO with length >=2.
-            // Even if a class has no explicit base classes,
-            // it will implicitly inherit from `object` at runtime;
-            // `object` will appear in the class's `__bases__` list and `__mro__`:
-            //
-            // ```pycon
-            // >>> class Foo: ...
-            // ...
-            // >>> Foo.__bases__
-            // (<class 'object'>,)
-            // >>> Foo.__mro__
-            // (<class '__main__.Foo'>, <class 'object'>)
-            // ```
-            [] => Ok(Self::from([ClassBase::Class(class), ClassBase::object(db)])),
-
-            // Fast path for a class that has only a single explicit base.
-            //
-            // This *could* theoretically be handled by the final branch below,
-            // but it's a common case (i.e., worth optimizing for),
-            // and the `c3_merge` function requires lots of allocations.
-            [single_base] => {
-                let single_base = ClassBase::try_from_ty(*single_base).ok_or(*single_base);
-                single_base.map_or_else(
-                    |invalid_base_ty| {
-                        let bases_info = Box::from([(0, invalid_base_ty)]);
-                        Err(MroErrorKind::InvalidBases(bases_info))
-                    },
-                    |single_base| {
-                        if let ClassBase::Class(class_base) = single_base {
-                            if class_is_cyclically_defined(db, class_base) {
-                                return Err(MroErrorKind::CyclicClassDefinition);
-                            }
-                        }
-                        let mro = std::iter::once(ClassBase::Class(class))
-                            .chain(single_base.mro(db))
-                            .collect();
-                        Ok(mro)
-                    },
-                )
-            }
-
-            // The class has multiple explicit bases.
-            //
-            // We'll fallback to a full implementation of the C3-merge algorithm to determine
-            // what MRO Python will give this class at runtime
-            // (if an MRO is indeed resolvable at all!)
-            multiple_bases => {
-                if class_is_cyclically_defined(db, class) {
-                    return Err(MroErrorKind::CyclicClassDefinition);
-                }
-
-                let mut valid_bases = vec![];
-                let mut invalid_bases = vec![];
-
-                for (i, base) in multiple_bases.iter().enumerate() {
-                    match ClassBase::try_from_ty(*base).ok_or(*base) {
-                        Ok(valid_base) => valid_bases.push(valid_base),
-                        Err(invalid_base) => invalid_bases.push((i, invalid_base)),
-                    }
-                }
-
-                if !invalid_bases.is_empty() {
-                    return Err(MroErrorKind::InvalidBases(invalid_bases.into_boxed_slice()));
-                }
-
-                let mut seqs = vec![VecDeque::from([ClassBase::Class(class)])];
-                for base in &valid_bases {
-                    seqs.push(base.mro(db).collect());
-                }
-                seqs.push(valid_bases.iter().copied().collect());
-
-                c3_merge(seqs).ok_or_else(|| {
-                    let mut seen_bases = FxHashSet::default();
-                    let mut duplicate_bases = vec![];
-                    for (index, base) in valid_bases
-                        .iter()
-                        .enumerate()
-                        .filter_map(|(index, base)| Some((index, base.into_class_literal_type()?)))
-                    {
-                        if !seen_bases.insert(base) {
-                            duplicate_bases.push((index, base));
-                        }
-                    }
-
-                    if duplicate_bases.is_empty() {
-                        MroErrorKind::UnresolvableMro {
-                            bases_list: valid_bases.into_boxed_slice(),
-                        }
-                    } else {
-                        MroErrorKind::DuplicateBases(duplicate_bases.into_boxed_slice())
-                    }
-                })
-            }
-        }
-    }
-}
-
-impl<'db, const N: usize> From<[ClassBase<'db>; N]> for Mro<'db> {
-    fn from(value: [ClassBase<'db>; N]) -> Self {
-        Self(Box::from(value))
-    }
-}
-
-impl<'db> From<Vec<ClassBase<'db>>> for Mro<'db> {
-    fn from(value: Vec<ClassBase<'db>>) -> Self {
-        Self(value.into_boxed_slice())
-    }
-}
-
-impl<'db> Deref for Mro<'db> {
-    type Target = [ClassBase<'db>];
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl<'db> FromIterator<ClassBase<'db>> for Mro<'db> {
-    fn from_iter<T: IntoIterator<Item = ClassBase<'db>>>(iter: T) -> Self {
-        Self(iter.into_iter().collect())
-    }
-}
-
-/// Iterator that yields elements of a class's MRO.
-///
-/// We avoid materialising the *full* MRO unless it is actually necessary:
-/// - Materialising the full MRO is expensive
-/// - We need to do it for every class in the code that we're checking, as we need to make sure
-///   that there are no class definitions in the code we're checking that would cause an
-///   exception to be raised at runtime. But the same does *not* necessarily apply for every class
-///   in third-party and stdlib dependencies: we never emit diagnostics about non-first-party code.
-/// - However, we *do* need to resolve attribute accesses on classes/instances from
-///   third-party and stdlib dependencies. That requires iterating over the MRO of third-party/stdlib
-///   classes, but not necessarily the *whole* MRO: often just the first element is enough.
-///   Luckily we know that for any class `X`, the first element of `X`'s MRO will always be `X` itself.
-///   We can therefore avoid resolving the full MRO for many third-party/stdlib classes while still
-///   being faithful to the runtime semantics.
-///
-/// Even for first-party code, where we will have to resolve the MRO for every class we encounter,
-/// loading the cached MRO comes with a certain amount of overhead, so it's best to avoid calling the
-/// Salsa-tracked [`Class::try_mro`] method unless it's absolutely necessary.
-pub(super) struct MroIterator<'db> {
-    db: &'db dyn Db,
-
-    /// The class whose MRO we're iterating over
-    class: Class<'db>,
-
-    /// Whether or not we've already yielded the first element of the MRO
-    first_element_yielded: bool,
-
-    /// Iterator over all elements of the MRO except the first.
-    ///
-    /// The full MRO is expensive to materialize, so this field is `None`
-    /// unless we actually *need* to iterate past the first element of the MRO,
-    /// at which point it is lazily materialized.
-    subsequent_elements: Option<std::slice::Iter<'db, ClassBase<'db>>>,
-}
-
-impl<'db> MroIterator<'db> {
-    pub(super) fn new(db: &'db dyn Db, class: Class<'db>) -> Self {
-        Self {
-            db,
-            class,
-            first_element_yielded: false,
-            subsequent_elements: None,
-        }
-    }
-
-    /// Materialize the full MRO of the class.
-    /// Return an iterator over that MRO which skips the first element of the MRO.
-    fn full_mro_except_first_element(&mut self) -> impl Iterator<Item = ClassBase<'db>> + '_ {
-        self.subsequent_elements
-            .get_or_insert_with(|| {
-                let mut full_mro_iter = match self.class.try_mro(self.db) {
-                    Ok(mro) => mro.iter(),
-                    Err(error) => error.fallback_mro().iter(),
-                };
-                full_mro_iter.next();
-                full_mro_iter
-            })
-            .copied()
-    }
-}
-
-impl<'db> Iterator for MroIterator<'db> {
-    type Item = ClassBase<'db>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        if !self.first_element_yielded {
-            self.first_element_yielded = true;
-            return Some(ClassBase::Class(self.class));
-        }
-        self.full_mro_except_first_element().next()
-    }
-}
-
-impl std::iter::FusedIterator for MroIterator<'_> {}
-
-#[derive(Debug, PartialEq, Eq)]
-pub(super) struct MroError<'db> {
-    kind: MroErrorKind<'db>,
-    fallback_mro: Mro<'db>,
-}
-
-impl<'db> MroError<'db> {
-    /// Return an [`MroErrorKind`] variant describing why we could not resolve the MRO for this class.
-    pub(super) fn reason(&self) -> &MroErrorKind<'db> {
-        &self.kind
-    }
-
-    /// Return the fallback MRO we should infer for this class during type inference
-    /// (since accurate resolution of its "true" MRO was impossible)
-    pub(super) fn fallback_mro(&self) -> &Mro<'db> {
-        &self.fallback_mro
-    }
-}
-
-/// Possible ways in which attempting to resolve the MRO of a class might fail.
-#[derive(Debug, PartialEq, Eq)]
-pub(super) enum MroErrorKind<'db> {
-    /// The class inherits from one or more invalid bases.
-    ///
-    /// To avoid excessive complexity in our implementation,
-    /// we only permit classes to inherit from class-literal types,
-    /// `Todo`, `Unknown` or `Any`. Anything else results in us
-    /// emitting a diagnostic.
-    ///
-    /// This variant records the indices and types of class bases
-    /// that we deem to be invalid. The indices are the indices of nodes
-    /// in the bases list of the class's [`StmtClassDef`](ruff_python_ast::StmtClassDef) node.
-    /// Each index is the index of a node representing an invalid base.
-    InvalidBases(Box<[(usize, Type<'db>)]>),
-
-    /// The class inherits from itself!
-    ///
-    /// This is very unlikely to happen in working real-world code,
-    /// but it's important to explicitly account for it.
-    /// If we don't, there's a possibility of an infinite loop and a panic.
-    CyclicClassDefinition,
-
-    /// The class has one or more duplicate bases.
-    ///
-    /// This variant records the indices and [`Class`]es
-    /// of the duplicate bases. The indices are the indices of nodes
-    /// in the bases list of the class's [`StmtClassDef`](ruff_python_ast::StmtClassDef) node.
-    /// Each index is the index of a node representing a duplicate base.
-    DuplicateBases(Box<[(usize, Class<'db>)]>),
-
-    /// The MRO is otherwise unresolvable through the C3-merge algorithm.
-    ///
-    /// See [`c3_merge`] for more details.
-    UnresolvableMro { bases_list: Box<[ClassBase<'db>]> },
-}
-
-/// Enumeration of the possible kinds of types we allow in class bases.
-///
-/// This is much more limited than the [`Type`] enum:
-/// all types that would be invalid to have as a class base are
-/// transformed into [`ClassBase::Unknown`]
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub(super) enum ClassBase<'db> {
-    Any,
-    Unknown,
-    Todo,
-    Class(Class<'db>),
-}
-
-impl<'db> ClassBase<'db> {
-    pub(super) fn display(self, db: &'db dyn Db) -> impl std::fmt::Display + 'db {
-        struct Display<'db> {
-            base: ClassBase<'db>,
-            db: &'db dyn Db,
-        }
-
-        impl std::fmt::Display for Display<'_> {
-            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                match self.base {
-                    ClassBase::Any => f.write_str("Any"),
-                    ClassBase::Todo => f.write_str("Todo"),
-                    ClassBase::Unknown => f.write_str("Unknown"),
-                    ClassBase::Class(class) => write!(f, "<class '{}'>", class.name(self.db)),
-                }
-            }
-        }
-
-        Display { base: self, db }
-    }
-
-    #[cfg(test)]
-    #[track_caller]
-    pub(super) fn expect_class_base(self) -> Class<'db> {
-        match self {
-            ClassBase::Class(class) => class,
-            _ => panic!("Expected a `ClassBase::Class()` variant"),
-        }
-    }
-
-    /// Return a `ClassBase` representing the class `builtins.object`
-    fn object(db: &'db dyn Db) -> Self {
-        KnownClass::Object
-            .to_class(db)
-            .into_class_literal()
-            .map_or(Self::Unknown, |ClassLiteralType { class }| {
-                Self::Class(class)
-            })
-    }
-
-    /// Attempt to resolve `ty` into a `ClassBase`.
-    ///
-    /// Return `None` if `ty` is not an acceptable type for a class base.
-    fn try_from_ty(ty: Type<'db>) -> Option<Self> {
-        match ty {
-            Type::Any => Some(Self::Any),
-            Type::Unknown => Some(Self::Unknown),
-            Type::Todo => Some(Self::Todo),
-            Type::ClassLiteral(ClassLiteralType { class }) => Some(Self::Class(class)),
-            Type::Union(_) => None, // TODO -- forces consideration of multiple possible MROs?
-            Type::Intersection(_) => None, // TODO -- probably incorrect?
-            Type::Instance(_) => None, // TODO -- handle `__mro_entries__`?
-            Type::Never
-            | Type::BooleanLiteral(_)
-            | Type::FunctionLiteral(_)
-            | Type::BytesLiteral(_)
-            | Type::IntLiteral(_)
-            | Type::StringLiteral(_)
-            | Type::LiteralString
-            | Type::Tuple(_)
-            | Type::SliceLiteral(_)
-            | Type::ModuleLiteral(_)
-            | Type::SubclassOf(_) => None,
-            Type::KnownInstance(known_instance) => match known_instance {
-                KnownInstanceType::Literal => None,
-            },
-        }
-    }
-
-    fn into_class_literal_type(self) -> Option<Class<'db>> {
-        match self {
-            Self::Class(class) => Some(class),
-            _ => None,
-        }
-    }
-
-    /// Iterate over the MRO of this base
-    fn mro(
-        self,
-        db: &'db dyn Db,
-    ) -> Either<impl Iterator<Item = ClassBase<'db>>, impl Iterator<Item = ClassBase<'db>>> {
-        match self {
-            ClassBase::Any => Either::Left([ClassBase::Any, ClassBase::object(db)].into_iter()),
-            ClassBase::Unknown => {
-                Either::Left([ClassBase::Unknown, ClassBase::object(db)].into_iter())
-            }
-            ClassBase::Todo => Either::Left([ClassBase::Todo, ClassBase::object(db)].into_iter()),
-            ClassBase::Class(class) => Either::Right(class.iter_mro(db)),
-        }
-    }
-}
-
-impl<'db> From<ClassBase<'db>> for Type<'db> {
-    fn from(value: ClassBase<'db>) -> Self {
-        match value {
-            ClassBase::Any => Type::Any,
-            ClassBase::Todo => Type::Todo,
-            ClassBase::Unknown => Type::Unknown,
-            ClassBase::Class(class) => Type::ClassLiteral(ClassLiteralType { class }),
-        }
-    }
-}
-
-/// Implementation of the [C3-merge algorithm] for calculating a Python class's
-/// [method resolution order].
-///
-/// [C3-merge algorithm]: https://docs.python.org/3/howto/mro.html#python-2-3-mro
-/// [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
-fn c3_merge(mut sequences: Vec<VecDeque<ClassBase>>) -> Option<Mro> {
-    // Most MROs aren't that long...
-    let mut mro = Vec::with_capacity(8);
-
-    loop {
-        sequences.retain(|sequence| !sequence.is_empty());
-
-        if sequences.is_empty() {
-            return Some(Mro::from(mro));
-        }
-
-        // If the candidate exists "deeper down" in the inheritance hierarchy,
-        // we should refrain from adding it to the MRO for now. Add the first candidate
-        // for which this does not hold true. If this holds true for all candidates,
-        // return `None`; it will be impossible to find a consistent MRO for the class
-        // with the given bases.
-        let mro_entry = sequences.iter().find_map(|outer_sequence| {
-            let candidate = outer_sequence[0];
-
-            let not_head = sequences
-                .iter()
-                .all(|sequence| sequence.iter().skip(1).all(|base| base != &candidate));
-
-            not_head.then_some(candidate)
-        })?;
-
-        mro.push(mro_entry);
-
-        // Make sure we don't try to add the candidate to the MRO twice:
-        for sequence in &mut sequences {
-            if sequence[0] == mro_entry {
-                sequence.pop_front();
-            }
-        }
-    }
-}
-
-/// Return `true` if this class appears to be a cyclic definition,
-/// i.e., it inherits either directly or indirectly from itself.
-///
-/// A class definition like this will fail at runtime,
-/// but we must be resilient to it or we could panic.
-fn class_is_cyclically_defined(db: &dyn Db, class: Class) -> bool {
-    fn is_cyclically_defined_recursive<'db>(
-        db: &'db dyn Db,
-        class: Class<'db>,
-        classes_to_watch: &mut IndexSet<Class<'db>>,
-    ) -> bool {
-        if !classes_to_watch.insert(class) {
-            return true;
-        }
-        for explicit_base_class in class
-            .explicit_bases(db)
-            .iter()
-            .copied()
-            .filter_map(Type::into_class_literal)
-            .map(|ClassLiteralType { class }| class)
-        {
-            // Each base must be considered in isolation.
-            // This is due to the fact that if a class uses multiple inheritance,
-            // there could easily be a situation where two bases have the same class in their MROs;
-            // that isn't enough to constitute the class being cyclically defined.
-            let classes_to_watch_len = classes_to_watch.len();
-            if is_cyclically_defined_recursive(db, explicit_base_class, classes_to_watch) {
-                return true;
-            }
-            classes_to_watch.truncate(classes_to_watch_len);
-        }
-        false
-    }
-
-    class
-        .explicit_bases(db)
-        .iter()
-        .copied()
-        .filter_map(Type::into_class_literal)
-        .map(|ClassLiteralType { class }| class)
-        .any(|base_class| is_cyclically_defined_recursive(db, base_class, &mut IndexSet::default()))
-}

crates/red_knot_python_semantic/src/types/narrow.rs

@@ -1,19 +1,16 @@
 use crate::semantic_index::ast_ids::HasScopedAstId;
-use crate::semantic_index::constraint::{Constraint, ConstraintNode, PatternConstraint};
+use crate::semantic_index::constraint::{Constraint, PatternConstraint};
 use crate::semantic_index::definition::Definition;
 use crate::semantic_index::expression::Expression;
 use crate::semantic_index::symbol::{ScopeId, ScopedSymbolId, SymbolTable};
 use crate::semantic_index::symbol_table;
 use crate::types::{
-    infer_expression_types, ClassLiteralType, InstanceType, IntersectionBuilder, KnownClass,
-    KnownConstraintFunction, KnownFunction, Truthiness, Type, UnionBuilder,
+    infer_expression_types, IntersectionBuilder, KnownFunction, Type, UnionBuilder,
 };
 use crate::Db;
 use itertools::Itertools;
 use ruff_python_ast as ast;
-use ruff_python_ast::{BoolOp, ExprBoolOp};
 use rustc_hash::FxHashMap;
-use std::collections::hash_map::Entry;
 use std::sync::Arc;
 
 /// Return the type constraint that `test` (if true) would place on `definition`, if any.
@@ -37,20 +34,15 @@ pub(crate) fn narrowing_constraint<'db>(
     constraint: Constraint<'db>,
     definition: Definition<'db>,
 ) -> Option<Type<'db>> {
-    let constraints = match constraint.node {
-        ConstraintNode::Expression(expression) => {
-            if constraint.is_positive {
-                all_narrowing_constraints_for_expression(db, expression)
-            } else {
-                all_negative_narrowing_constraints_for_expression(db, expression)
-            }
+    match constraint {
+        Constraint::Expression(expression) => {
+            all_narrowing_constraints_for_expression(db, expression)
+                .get(&definition.symbol(db))
+                .copied()
         }
-        ConstraintNode::Pattern(pattern) => all_narrowing_constraints_for_pattern(db, pattern),
-    };
-    if let Some(constraints) = constraints {
-        constraints.get(&definition.symbol(db)).copied()
-    } else {
-        None
+        Constraint::Pattern(pattern) => all_narrowing_constraints_for_pattern(db, pattern)
+            .get(&definition.symbol(db))
+            .copied(),
     }
 }
 
@@ -58,184 +50,106 @@ pub(crate) fn narrowing_constraint<'db>(
 fn all_narrowing_constraints_for_pattern<'db>(
     db: &'db dyn Db,
     pattern: PatternConstraint<'db>,
-) -> Option<NarrowingConstraints<'db>> {
-    NarrowingConstraintsBuilder::new(db, ConstraintNode::Pattern(pattern), true).finish()
+) -> NarrowingConstraints<'db> {
+    NarrowingConstraintsBuilder::new(db, Constraint::Pattern(pattern)).finish()
 }
 
 #[salsa::tracked(return_ref)]
 fn all_narrowing_constraints_for_expression<'db>(
     db: &'db dyn Db,
     expression: Expression<'db>,
-) -> Option<NarrowingConstraints<'db>> {
-    NarrowingConstraintsBuilder::new(db, ConstraintNode::Expression(expression), true).finish()
+) -> NarrowingConstraints<'db> {
+    NarrowingConstraintsBuilder::new(db, Constraint::Expression(expression)).finish()
 }
 
-#[salsa::tracked(return_ref)]
-fn all_negative_narrowing_constraints_for_expression<'db>(
-    db: &'db dyn Db,
-    expression: Expression<'db>,
-) -> Option<NarrowingConstraints<'db>> {
-    NarrowingConstraintsBuilder::new(db, ConstraintNode::Expression(expression), false).finish()
-}
-
-/// Generate a constraint from the type of a `classinfo` argument to `isinstance` or `issubclass`.
+/// Generate a constraint from the *type* of the second argument of an `isinstance` call.
 ///
-/// The `classinfo` argument can be a class literal, a tuple of (tuples of) class literals. PEP 604
-/// union types are not yet supported. Returns `None` if the `classinfo` argument has a wrong type.
-fn generate_classinfo_constraint<'db, F>(
+/// Example: for `isinstance(…, str)`, we would infer `Type::ClassLiteral(str)` from the
+/// second argument, but we need to generate a `Type::Instance(str)` constraint that can
+/// be used to narrow down the type of the first argument.
+fn generate_isinstance_constraint<'db>(
     db: &'db dyn Db,
     classinfo: &Type<'db>,
-    to_constraint: F,
-) -> Option<Type<'db>>
-where
-    F: Fn(ClassLiteralType<'db>) -> Type<'db> + Copy,
-{
+) -> Option<Type<'db>> {
     match classinfo {
+        Type::ClassLiteral(class) => Some(Type::Instance(*class)),
         Type::Tuple(tuple) => {
             let mut builder = UnionBuilder::new(db);
             for element in tuple.elements(db) {
-                builder = builder.add(generate_classinfo_constraint(db, element, to_constraint)?);
+                builder = builder.add(generate_isinstance_constraint(db, element)?);
             }
             Some(builder.build())
         }
-        Type::ClassLiteral(class_literal_type) => Some(to_constraint(*class_literal_type)),
         _ => None,
     }
 }
 
 type NarrowingConstraints<'db> = FxHashMap<ScopedSymbolId, Type<'db>>;
 
-fn merge_constraints_and<'db>(
-    into: &mut NarrowingConstraints<'db>,
-    from: NarrowingConstraints<'db>,
-    db: &'db dyn Db,
-) {
-    for (key, value) in from {
-        match into.entry(key) {
-            Entry::Occupied(mut entry) => {
-                *entry.get_mut() = IntersectionBuilder::new(db)
-                    .add_positive(*entry.get())
-                    .add_positive(value)
-                    .build();
-            }
-            Entry::Vacant(entry) => {
-                entry.insert(value);
-            }
-        }
-    }
-}
-
-fn merge_constraints_or<'db>(
-    into: &mut NarrowingConstraints<'db>,
-    from: &NarrowingConstraints<'db>,
-    db: &'db dyn Db,
-) {
-    for (key, value) in from {
-        match into.entry(*key) {
-            Entry::Occupied(mut entry) => {
-                *entry.get_mut() = UnionBuilder::new(db).add(*entry.get()).add(*value).build();
-            }
-            Entry::Vacant(entry) => {
-                entry.insert(KnownClass::Object.to_instance(db));
-            }
-        }
-    }
-    for (key, value) in into.iter_mut() {
-        if !from.contains_key(key) {
-            *value = KnownClass::Object.to_instance(db);
-        }
-    }
-}
-
 struct NarrowingConstraintsBuilder<'db> {
     db: &'db dyn Db,
-    constraint: ConstraintNode<'db>,
-    is_positive: bool,
+    constraint: Constraint<'db>,
+    constraints: NarrowingConstraints<'db>,
 }
 
 impl<'db> NarrowingConstraintsBuilder<'db> {
-    fn new(db: &'db dyn Db, constraint: ConstraintNode<'db>, is_positive: bool) -> Self {
+    fn new(db: &'db dyn Db, constraint: Constraint<'db>) -> Self {
         Self {
             db,
             constraint,
-            is_positive,
+            constraints: NarrowingConstraints::default(),
         }
     }
 
-    fn finish(mut self) -> Option<NarrowingConstraints<'db>> {
-        let constraints: Option<NarrowingConstraints<'db>> = match self.constraint {
-            ConstraintNode::Expression(expression) => {
-                self.evaluate_expression_constraint(expression, self.is_positive)
-            }
-            ConstraintNode::Pattern(pattern) => self.evaluate_pattern_constraint(pattern),
-        };
-        if let Some(mut constraints) = constraints {
-            constraints.shrink_to_fit();
-            Some(constraints)
-        } else {
-            None
+    fn finish(mut self) -> NarrowingConstraints<'db> {
+        match self.constraint {
+            Constraint::Expression(expression) => self.evaluate_expression_constraint(expression),
+            Constraint::Pattern(pattern) => self.evaluate_pattern_constraint(pattern),
         }
+
+        self.constraints.shrink_to_fit();
+        self.constraints
     }
 
-    fn evaluate_expression_constraint(
-        &mut self,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
-        let expression_node = expression.node_ref(self.db).node();
-        self.evaluate_expression_node_constraint(expression_node, expression, is_positive)
-    }
-
-    fn evaluate_expression_node_constraint(
-        &mut self,
-        expression_node: &ruff_python_ast::Expr,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
-        match expression_node {
+    fn evaluate_expression_constraint(&mut self, expression: Expression<'db>) {
+        match expression.node_ref(self.db).node() {
             ast::Expr::Compare(expr_compare) => {
-                self.evaluate_expr_compare(expr_compare, expression, is_positive)
+                self.add_expr_compare(expr_compare, expression);
             }
             ast::Expr::Call(expr_call) => {
-                self.evaluate_expr_call(expr_call, expression, is_positive)
+                self.add_expr_call(expr_call, expression);
             }
-            ast::Expr::UnaryOp(unary_op) if unary_op.op == ast::UnaryOp::Not => self
-                .evaluate_expression_node_constraint(&unary_op.operand, expression, !is_positive),
-            ast::Expr::BoolOp(bool_op) => self.evaluate_bool_op(bool_op, expression, is_positive),
-            _ => None, // TODO other test expression kinds
+            _ => {} // TODO other test expression kinds
         }
     }
 
-    fn evaluate_pattern_constraint(
-        &mut self,
-        pattern: PatternConstraint<'db>,
-    ) -> Option<NarrowingConstraints<'db>> {
+    fn evaluate_pattern_constraint(&mut self, pattern: PatternConstraint<'db>) {
         let subject = pattern.subject(self.db);
 
         match pattern.pattern(self.db).node() {
             ast::Pattern::MatchValue(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchSingleton(singleton_pattern) => {
-                self.evaluate_match_pattern_singleton(subject, singleton_pattern)
+                self.add_match_pattern_singleton(subject, singleton_pattern);
             }
             ast::Pattern::MatchSequence(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchMapping(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchClass(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchStar(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchAs(_) => {
-                None // TODO
+                // TODO
             }
             ast::Pattern::MatchOr(_) => {
-                None // TODO
+                // TODO
             }
         }
     }
@@ -246,17 +160,12 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
 
     fn scope(&self) -> ScopeId<'db> {
         match self.constraint {
-            ConstraintNode::Expression(expression) => expression.scope(self.db),
-            ConstraintNode::Pattern(pattern) => pattern.scope(self.db),
+            Constraint::Expression(expression) => expression.scope(self.db),
+            Constraint::Pattern(pattern) => pattern.scope(self.db),
         }
     }
 
-    fn evaluate_expr_compare(
-        &mut self,
-        expr_compare: &ast::ExprCompare,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
+    fn add_expr_compare(&mut self, expr_compare: &ast::ExprCompare, expression: Expression<'db>) {
         let ast::ExprCompare {
             range: _,
             left,
@@ -266,14 +175,7 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         if !left.is_name_expr() && comparators.iter().all(|c| !c.is_name_expr()) {
             // If none of the comparators are name expressions,
             // we have no symbol to narrow down the type of.
-            return None;
-        }
-        if !is_positive && comparators.len() > 1 {
-            // We can't negate a constraint made by a multi-comparator expression, since we can't
-            // know which comparison part is the one being negated.
-            // For example, the negation of  `x is 1 is y is 2`, would be `(x is not 1) or (y is not 1) or (y is not 2)`
-            // and that requires cross-symbol constraints, which we don't support yet.
-            return None;
+            return;
         }
         let scope = self.scope();
         let inference = infer_expression_types(self.db, expression);
@@ -281,7 +183,6 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
         let comparator_tuples = std::iter::once(&**left)
             .chain(comparators)
             .tuple_windows::<(&ruff_python_ast::Expr, &ruff_python_ast::Expr)>();
-        let mut constraints = NarrowingConstraints::default();
         for (op, (left, right)) in std::iter::zip(&**ops, comparator_tuples) {
             if let ast::Expr::Name(ast::ExprName {
                 range: _,
@@ -291,28 +192,27 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
             {
                 // SAFETY: we should always have a symbol for every Name node.
                 let symbol = self.symbols().symbol_id_by_name(id).unwrap();
-                let rhs_ty = inference.expression_ty(right.scoped_ast_id(self.db, scope));
-
-                match if is_positive { *op } else { op.negate() } {
+                let comp_ty = inference.expression_ty(right.scoped_ast_id(self.db, scope));
+                match op {
                     ast::CmpOp::IsNot => {
-                        if rhs_ty.is_singleton(self.db) {
+                        if comp_ty.is_singleton() {
                             let ty = IntersectionBuilder::new(self.db)
-                                .add_negative(rhs_ty)
+                                .add_negative(comp_ty)
                                 .build();
-                            constraints.insert(symbol, ty);
+                            self.constraints.insert(symbol, ty);
                         } else {
                             // Non-singletons cannot be safely narrowed using `is not`
                         }
                     }
                     ast::CmpOp::Is => {
-                        constraints.insert(symbol, rhs_ty);
+                        self.constraints.insert(symbol, comp_ty);
                     }
                     ast::CmpOp::NotEq => {
-                        if rhs_ty.is_single_valued(self.db) {
+                        if comp_ty.is_single_valued(self.db) {
                             let ty = IntersectionBuilder::new(self.db)
-                                .add_negative(rhs_ty)
+                                .add_negative(comp_ty)
                                 .build();
-                            constraints.insert(symbol, ty);
+                            self.constraints.insert(symbol, ty);
                         }
                     }
                     _ => {
@@ -321,137 +221,50 @@ impl<'db> NarrowingConstraintsBuilder<'db> {
                 }
             }
         }
-        Some(constraints)
     }
 
-    fn evaluate_expr_call(
-        &mut self,
-        expr_call: &ast::ExprCall,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
+    fn add_expr_call(&mut self, expr_call: &ast::ExprCall, expression: Expression<'db>) {
         let scope = self.scope();
         let inference = infer_expression_types(self.db, expression);
 
-        // TODO: add support for PEP 604 union types on the right hand side of `isinstance`
-        // and `issubclass`, for example `isinstance(x, str | (int | float))`.
-        match inference
+        if let Some(func_type) = inference
             .expression_ty(expr_call.func.scoped_ast_id(self.db, scope))
-            .into_function_literal()
-            .and_then(|f| f.known(self.db))
-            .and_then(KnownFunction::constraint_function)
+            .into_function_literal_type()
         {
-            Some(function) if expr_call.arguments.keywords.is_empty() => {
-                if let [ast::Expr::Name(ast::ExprName { id, .. }), class_info] =
-                    &*expr_call.arguments.args
+            if func_type.is_known(self.db, KnownFunction::IsInstance)
+                && expr_call.arguments.keywords.is_empty()
+            {
+                if let [ast::Expr::Name(ast::ExprName { id, .. }), rhs] = &*expr_call.arguments.args
                 {
                     let symbol = self.symbols().symbol_id_by_name(id).unwrap();
 
-                    let class_info_ty =
-                        inference.expression_ty(class_info.scoped_ast_id(self.db, scope));
+                    let rhs_type = inference.expression_ty(rhs.scoped_ast_id(self.db, scope));
 
-                    let to_constraint = match function {
-                        KnownConstraintFunction::IsInstance => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::Instance(InstanceType {
-                                    class: class_literal.class,
-                                })
-                            }
-                        }
-                        KnownConstraintFunction::IsSubclass => {
-                            |class_literal: ClassLiteralType<'db>| {
-                                Type::SubclassOf(class_literal.to_subclass_of_type())
-                            }
-                        }
-                    };
-
-                    generate_classinfo_constraint(self.db, &class_info_ty, to_constraint).map(
-                        |constraint| {
-                            let mut constraints = NarrowingConstraints::default();
-                            constraints.insert(symbol, constraint.negate_if(self.db, !is_positive));
-                            constraints
-                        },
-                    )
-                } else {
-                    None
+                    // TODO: add support for PEP 604 union types on the right hand side:
+                    // isinstance(x, str | (int | float))
+                    if let Some(constraint) = generate_isinstance_constraint(self.db, &rhs_type) {
+                        self.constraints.insert(symbol, constraint);
+                    }
                 }
             }
-            _ => None,
         }
     }
 
-    fn evaluate_match_pattern_singleton(
+    fn add_match_pattern_singleton(
         &mut self,
         subject: &ast::Expr,
         pattern: &ast::PatternMatchSingleton,
-    ) -> Option<NarrowingConstraints<'db>> {
+    ) {
         if let Some(ast::ExprName { id, .. }) = subject.as_name_expr() {
             // SAFETY: we should always have a symbol for every Name node.
             let symbol = self.symbols().symbol_id_by_name(id).unwrap();
 
             let ty = match pattern.value {
-                ast::Singleton::None => Type::none(self.db),
+                ast::Singleton::None => Type::None,
                 ast::Singleton::True => Type::BooleanLiteral(true),
                 ast::Singleton::False => Type::BooleanLiteral(false),
             };
-            let mut constraints = NarrowingConstraints::default();
-            constraints.insert(symbol, ty);
-            Some(constraints)
-        } else {
-            None
-        }
-    }
-
-    fn evaluate_bool_op(
-        &mut self,
-        expr_bool_op: &ExprBoolOp,
-        expression: Expression<'db>,
-        is_positive: bool,
-    ) -> Option<NarrowingConstraints<'db>> {
-        let inference = infer_expression_types(self.db, expression);
-        let scope = self.scope();
-        let mut sub_constraints = expr_bool_op
-            .values
-            .iter()
-            // filter our arms with statically known truthiness
-            .filter(|expr| {
-                inference
-                    .expression_ty(expr.scoped_ast_id(self.db, scope))
-                    .bool(self.db)
-                    != match expr_bool_op.op {
-                        BoolOp::And => Truthiness::AlwaysTrue,
-                        BoolOp::Or => Truthiness::AlwaysFalse,
-                    }
-            })
-            .map(|sub_expr| {
-                self.evaluate_expression_node_constraint(sub_expr, expression, is_positive)
-            })
-            .collect::<Vec<_>>();
-        match (expr_bool_op.op, is_positive) {
-            (BoolOp::And, true) | (BoolOp::Or, false) => {
-                let mut aggregation: Option<NarrowingConstraints> = None;
-                for sub_constraint in sub_constraints.into_iter().flatten() {
-                    if let Some(ref mut some_aggregation) = aggregation {
-                        merge_constraints_and(some_aggregation, sub_constraint, self.db);
-                    } else {
-                        aggregation = Some(sub_constraint);
-                    }
-                }
-                aggregation
-            }
-            (BoolOp::Or, true) | (BoolOp::And, false) => {
-                let (first, rest) = sub_constraints.split_first_mut()?;
-                if let Some(ref mut first) = first {
-                    for rest_constraint in rest {
-                        if let Some(rest_constraint) = rest_constraint {
-                            merge_constraints_or(first, rest_constraint, self.db);
-                        } else {
-                            return None;
-                        }
-                    }
-                }
-                first.clone()
-            }
+            self.constraints.insert(symbol, ty);
         }
     }
 }

crates/red_knot_python_semantic/src/types/unpacker.rs

@@ -1,143 +0,0 @@
-use std::borrow::Cow;
-
-use ruff_db::files::File;
-use ruff_python_ast::{self as ast, AnyNodeRef};
-use rustc_hash::FxHashMap;
-
-use crate::semantic_index::ast_ids::{HasScopedAstId, ScopedExpressionId};
-use crate::semantic_index::symbol::ScopeId;
-use crate::types::{TupleType, Type, TypeCheckDiagnostics, TypeCheckDiagnosticsBuilder};
-use crate::Db;
-
-/// Unpacks the value expression type to their respective targets.
-pub(crate) struct Unpacker<'db> {
-    db: &'db dyn Db,
-    targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnosticsBuilder<'db>,
-}
-
-impl<'db> Unpacker<'db> {
-    pub(crate) fn new(db: &'db dyn Db, file: File) -> Self {
-        Self {
-            db,
-            targets: FxHashMap::default(),
-            diagnostics: TypeCheckDiagnosticsBuilder::new(db, file),
-        }
-    }
-
-    pub(crate) fn unpack(&mut self, target: &ast::Expr, value_ty: Type<'db>, scope: ScopeId<'db>) {
-        match target {
-            ast::Expr::Name(target_name) => {
-                self.targets
-                    .insert(target_name.scoped_ast_id(self.db, scope), value_ty);
-            }
-            ast::Expr::Starred(ast::ExprStarred { value, .. }) => {
-                self.unpack(value, value_ty, scope);
-            }
-            ast::Expr::List(ast::ExprList { elts, .. })
-            | ast::Expr::Tuple(ast::ExprTuple { elts, .. }) => match value_ty {
-                Type::Tuple(tuple_ty) => {
-                    let starred_index = elts.iter().position(ast::Expr::is_starred_expr);
-
-                    let element_types = if let Some(starred_index) = starred_index {
-                        if tuple_ty.len(self.db) >= elts.len() - 1 {
-                            let mut element_types = Vec::with_capacity(elts.len());
-                            element_types.extend_from_slice(
-                                // SAFETY: Safe because of the length check above.
-                                &tuple_ty.elements(self.db)[..starred_index],
-                            );
-
-                            // E.g., in `(a, *b, c, d) = ...`, the index of starred element `b`
-                            // is 1 and the remaining elements after that are 2.
-                            let remaining = elts.len() - (starred_index + 1);
-                            // This index represents the type of the last element that belongs
-                            // to the starred expression, in an exclusive manner.
-                            let starred_end_index = tuple_ty.len(self.db) - remaining;
-                            // SAFETY: Safe because of the length check above.
-                            let _starred_element_types =
-                                &tuple_ty.elements(self.db)[starred_index..starred_end_index];
-                            // TODO: Combine the types into a list type. If the
-                            // starred_element_types is empty, then it should be `List[Any]`.
-                            // combine_types(starred_element_types);
-                            element_types.push(Type::Todo);
-
-                            element_types.extend_from_slice(
-                                // SAFETY: Safe because of the length check above.
-                                &tuple_ty.elements(self.db)[starred_end_index..],
-                            );
-                            Cow::Owned(element_types)
-                        } else {
-                            let mut element_types = tuple_ty.elements(self.db).to_vec();
-                            // Subtract 1 to insert the starred expression type at the correct
-                            // index.
-                            element_types.resize(elts.len() - 1, Type::Unknown);
-                            // TODO: This should be `list[Unknown]`
-                            element_types.insert(starred_index, Type::Todo);
-                            Cow::Owned(element_types)
-                        }
-                    } else {
-                        Cow::Borrowed(tuple_ty.elements(self.db).as_ref())
-                    };
-
-                    for (index, element) in elts.iter().enumerate() {
-                        self.unpack(
-                            element,
-                            element_types.get(index).copied().unwrap_or(Type::Unknown),
-                            scope,
-                        );
-                    }
-                }
-                Type::StringLiteral(string_literal_ty) => {
-                    // Deconstruct the string literal to delegate the inference back to the
-                    // tuple type for correct handling of starred expressions. We could go
-                    // further and deconstruct to an array of `StringLiteral` with each
-                    // individual character, instead of just an array of `LiteralString`, but
-                    // there would be a cost and it's not clear that it's worth it.
-                    let value_ty = Type::Tuple(TupleType::new(
-                        self.db,
-                        vec![Type::LiteralString; string_literal_ty.len(self.db)]
-                            .into_boxed_slice(),
-                    ));
-                    self.unpack(target, value_ty, scope);
-                }
-                _ => {
-                    let value_ty = if value_ty.is_literal_string() {
-                        Type::LiteralString
-                    } else {
-                        value_ty
-                            .iterate(self.db)
-                            .unwrap_with_diagnostic(AnyNodeRef::from(target), &mut self.diagnostics)
-                    };
-                    for element in elts {
-                        self.unpack(element, value_ty, scope);
-                    }
-                }
-            },
-            _ => {}
-        }
-    }
-
-    pub(crate) fn finish(mut self) -> UnpackResult<'db> {
-        self.targets.shrink_to_fit();
-        UnpackResult {
-            diagnostics: self.diagnostics.finish(),
-            targets: self.targets,
-        }
-    }
-}
-
-#[derive(Debug, Default, PartialEq, Eq)]
-pub(crate) struct UnpackResult<'db> {
-    targets: FxHashMap<ScopedExpressionId, Type<'db>>,
-    diagnostics: TypeCheckDiagnostics,
-}
-
-impl<'db> UnpackResult<'db> {
-    pub(crate) fn get(&self, expr_id: ScopedExpressionId) -> Option<Type<'db>> {
-        self.targets.get(&expr_id).copied()
-    }
-
-    pub(crate) fn diagnostics(&self) -> &TypeCheckDiagnostics {
-        &self.diagnostics
-    }
-}

crates/red_knot_python_semantic/src/unpack.rs

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

crates/red_knot_python_semantic/src/util/subscript.rs

@@ -1,192 +1,18 @@
-//! This module provides utility functions for indexing (`PyIndex`) and slicing
-//! operations (`PySlice`) on iterators, following the semantics of equivalent
-//! operations in Python.
-
-use itertools::Either;
-
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub(crate) struct OutOfBoundsError;
-
-pub(crate) trait PyIndex {
+pub(crate) trait PythonSubscript {
     type Item;
 
-    fn py_index(&mut self, index: i32) -> Result<Self::Item, OutOfBoundsError>;
+    fn python_subscript(&mut self, index: i64) -> Option<Self::Item>;
 }
 
-fn from_nonnegative_i32(index: i32) -> usize {
-    static_assertions::const_assert!(usize::BITS >= 32);
-    debug_assert!(index >= 0);
-
-    usize::try_from(index)
-        .expect("Should only ever pass a positive integer to `from_nonnegative_i32`")
-}
-
-fn from_negative_i32(index: i32) -> usize {
-    static_assertions::const_assert!(usize::BITS >= 32);
-
-    index.checked_neg().map(from_nonnegative_i32).unwrap_or({
-        // 'checked_neg' only fails for i32::MIN. We can not
-        // represent -i32::MIN as a i32, but we can represent
-        // it as a usize, since usize is at least 32 bits.
-        from_nonnegative_i32(i32::MAX) + 1
-    })
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, PartialOrd)]
-enum Position {
-    BeforeStart,
-    AtIndex(usize),
-    AfterEnd,
-}
-
-enum Nth {
-    FromStart(usize),
-    FromEnd(usize),
-}
-
-impl Nth {
-    fn from_index(index: i32) -> Self {
-        if index >= 0 {
-            Nth::FromStart(from_nonnegative_i32(index))
-        } else {
-            Nth::FromEnd(from_negative_i32(index) - 1)
-        }
-    }
-
-    fn to_position(&self, len: usize) -> Position {
-        debug_assert!(len > 0);
-
-        match self {
-            Nth::FromStart(nth) => {
-                if *nth < len {
-                    Position::AtIndex(*nth)
-                } else {
-                    Position::AfterEnd
-                }
-            }
-            Nth::FromEnd(nth_rev) => {
-                if *nth_rev < len {
-                    Position::AtIndex(len - 1 - *nth_rev)
-                } else {
-                    Position::BeforeStart
-                }
-            }
-        }
-    }
-}
-
-impl<I, T> PyIndex for T
-where
-    T: DoubleEndedIterator<Item = I>,
-{
+impl<I, T: DoubleEndedIterator<Item = I>> PythonSubscript for T {
     type Item = I;
 
-    fn py_index(&mut self, index: i32) -> Result<I, OutOfBoundsError> {
-        match Nth::from_index(index) {
-            Nth::FromStart(nth) => self.nth(nth).ok_or(OutOfBoundsError),
-            Nth::FromEnd(nth_rev) => self.nth_back(nth_rev).ok_or(OutOfBoundsError),
-        }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub(crate) struct StepSizeZeroError;
-
-pub(crate) trait PySlice {
-    type Item;
-
-    fn py_slice(
-        &self,
-        start: Option<i32>,
-        stop: Option<i32>,
-        step: Option<i32>,
-    ) -> Result<
-        Either<impl Iterator<Item = &Self::Item>, impl Iterator<Item = &Self::Item>>,
-        StepSizeZeroError,
-    >;
-}
-
-impl<T> PySlice for [T] {
-    type Item = T;
-
-    fn py_slice(
-        &self,
-        start: Option<i32>,
-        stop: Option<i32>,
-        step_int: Option<i32>,
-    ) -> Result<
-        Either<impl Iterator<Item = &Self::Item>, impl Iterator<Item = &Self::Item>>,
-        StepSizeZeroError,
-    > {
-        let step_int = step_int.unwrap_or(1);
-        if step_int == 0 {
-            return Err(StepSizeZeroError);
-        }
-
-        let len = self.len();
-        if len == 0 {
-            // The iterator needs to have the same type as the step>0 case below,
-            // so we need to use `.skip(0)`.
-            #[allow(clippy::iter_skip_zero)]
-            return Ok(Either::Left(self.iter().skip(0).take(0).step_by(1)));
-        }
-
-        let to_position = |index| Nth::from_index(index).to_position(len);
-
-        if step_int.is_positive() {
-            let step = from_nonnegative_i32(step_int);
-
-            let start = start.map(to_position).unwrap_or(Position::BeforeStart);
-            let stop = stop.map(to_position).unwrap_or(Position::AfterEnd);
-
-            let (skip, take, step) = if start < stop {
-                let skip = match start {
-                    Position::BeforeStart => 0,
-                    Position::AtIndex(start_index) => start_index,
-                    Position::AfterEnd => len,
-                };
-
-                let take = match stop {
-                    Position::BeforeStart => 0,
-                    Position::AtIndex(stop_index) => stop_index - skip,
-                    Position::AfterEnd => len - skip,
-                };
-
-                (skip, take, step)
-            } else {
-                (0, 0, step)
-            };
-
-            Ok(Either::Left(
-                self.iter().skip(skip).take(take).step_by(step),
-            ))
+    fn python_subscript(&mut self, index: i64) -> Option<I> {
+        if index >= 0 {
+            self.nth(usize::try_from(index).ok()?)
         } else {
-            let step = from_negative_i32(step_int);
-
-            let start = start.map(to_position).unwrap_or(Position::AfterEnd);
-            let stop = stop.map(to_position).unwrap_or(Position::BeforeStart);
-
-            let (skip, take, step) = if start <= stop {
-                (0, 0, step)
-            } else {
-                let skip = match start {
-                    Position::BeforeStart => len,
-                    Position::AtIndex(start_index) => len - 1 - start_index,
-                    Position::AfterEnd => 0,
-                };
-
-                let take = match stop {
-                    Position::BeforeStart => len - skip,
-                    Position::AtIndex(stop_index) => (len - 1) - skip - stop_index,
-                    Position::AfterEnd => 0,
-                };
-
-                (skip, take, step)
-            };
-
-            Ok(Either::Right(
-                self.iter().rev().skip(skip).take(take).step_by(step),
-            ))
+            let nth_rev = usize::try_from(index.checked_neg()?).ok()?.checked_sub(1)?;
+            self.rev().nth(nth_rev)
         }
     }
 }
@@ -194,309 +20,64 @@ impl<T> PySlice for [T] {
 #[cfg(test)]
 #[allow(clippy::redundant_clone)]
 mod tests {
-    use crate::util::subscript::{OutOfBoundsError, StepSizeZeroError};
-
-    use super::{PyIndex, PySlice};
-    use itertools::assert_equal;
+    use super::PythonSubscript;
 
     #[test]
-    fn py_index_empty() {
-        let iter = std::iter::empty::<char>();
+    fn python_subscript_basic() {
+        let iter = 'a'..='e';
 
-        assert_eq!(iter.clone().py_index(0), Err(OutOfBoundsError));
-        assert_eq!(iter.clone().py_index(1), Err(OutOfBoundsError));
-        assert_eq!(iter.clone().py_index(-1), Err(OutOfBoundsError));
-        assert_eq!(iter.clone().py_index(i32::MIN), Err(OutOfBoundsError));
-        assert_eq!(iter.clone().py_index(i32::MAX), Err(OutOfBoundsError));
+        assert_eq!(iter.clone().python_subscript(0), Some('a'));
+        assert_eq!(iter.clone().python_subscript(1), Some('b'));
+        assert_eq!(iter.clone().python_subscript(4), Some('e'));
+        assert_eq!(iter.clone().python_subscript(5), None);
+
+        assert_eq!(iter.clone().python_subscript(-1), Some('e'));
+        assert_eq!(iter.clone().python_subscript(-2), Some('d'));
+        assert_eq!(iter.clone().python_subscript(-5), Some('a'));
+        assert_eq!(iter.clone().python_subscript(-6), None);
     }
 
     #[test]
-    fn py_index_single_element() {
-        let iter = ['a'].into_iter();
+    fn python_subscript_empty() {
+        let iter = 'a'..'a';
 
-        assert_eq!(iter.clone().py_index(0), Ok('a'));
-        assert_eq!(iter.clone().py_index(1), Err(OutOfBoundsError));
-        assert_eq!(iter.clone().py_index(-1), Ok('a'));
-        assert_eq!(iter.clone().py_index(-2), Err(OutOfBoundsError));
+        assert_eq!(iter.clone().python_subscript(0), None);
+        assert_eq!(iter.clone().python_subscript(1), None);
+        assert_eq!(iter.clone().python_subscript(-1), None);
     }
 
     #[test]
-    fn py_index_more_elements() {
-        let iter = ['a', 'b', 'c', 'd', 'e'].into_iter();
+    fn python_subscript_single_element() {
+        let iter = 'a'..='a';
 
-        assert_eq!(iter.clone().py_index(0), Ok('a'));
-        assert_eq!(iter.clone().py_index(1), Ok('b'));
-        assert_eq!(iter.clone().py_index(4), Ok('e'));
-        assert_eq!(iter.clone().py_index(5), Err(OutOfBoundsError));
-
-        assert_eq!(iter.clone().py_index(-1), Ok('e'));
-        assert_eq!(iter.clone().py_index(-2), Ok('d'));
-        assert_eq!(iter.clone().py_index(-5), Ok('a'));
-        assert_eq!(iter.clone().py_index(-6), Err(OutOfBoundsError));
+        assert_eq!(iter.clone().python_subscript(0), Some('a'));
+        assert_eq!(iter.clone().python_subscript(1), None);
+        assert_eq!(iter.clone().python_subscript(-1), Some('a'));
+        assert_eq!(iter.clone().python_subscript(-2), None);
     }
 
     #[test]
-    fn py_index_uses_full_index_range() {
-        let iter = 0..=u32::MAX;
+    fn python_subscript_uses_full_index_range() {
+        let iter = 0..=u64::MAX;
 
-        // u32::MAX - |i32::MIN| + 1 = 2^32 - 1 - 2^31 + 1 = 2^31
-        assert_eq!(iter.clone().py_index(i32::MIN), Ok(2u32.pow(31)));
-        assert_eq!(iter.clone().py_index(-2), Ok(u32::MAX - 2 + 1));
-        assert_eq!(iter.clone().py_index(-1), Ok(u32::MAX - 1 + 1));
+        assert_eq!(iter.clone().python_subscript(0), Some(0));
+        assert_eq!(iter.clone().python_subscript(1), Some(1));
+        assert_eq!(
+            iter.clone().python_subscript(i64::MAX),
+            Some(i64::MAX as u64)
+        );
 
-        assert_eq!(iter.clone().py_index(0), Ok(0));
-        assert_eq!(iter.clone().py_index(1), Ok(1));
-        assert_eq!(iter.clone().py_index(i32::MAX), Ok(i32::MAX as u32));
-    }
+        assert_eq!(iter.clone().python_subscript(-1), Some(u64::MAX));
+        assert_eq!(iter.clone().python_subscript(-2), Some(u64::MAX - 1));
 
-    #[track_caller]
-    fn assert_eq_slice<const N: usize, const M: usize>(
-        input: &[char; N],
-        start: Option<i32>,
-        stop: Option<i32>,
-        step: Option<i32>,
-        expected: &[char; M],
-    ) {
-        assert_equal(input.py_slice(start, stop, step).unwrap(), expected.iter());
-    }
+        // i64::MIN is not representable as a positive number, so it is not
+        // a valid index:
+        assert_eq!(iter.clone().python_subscript(i64::MIN), None);
 
-    #[test]
-    fn py_slice_empty_input() {
-        let input = [];
-
-        assert_eq_slice(&input, None, None, None, &[]);
-        assert_eq_slice(&input, Some(0), None, None, &[]);
-        assert_eq_slice(&input, None, Some(0), None, &[]);
-        assert_eq_slice(&input, Some(0), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(-5), Some(-5), None, &[]);
-        assert_eq_slice(&input, None, None, Some(-1), &[]);
-        assert_eq_slice(&input, None, None, Some(2), &[]);
-    }
-
-    #[test]
-    fn py_slice_single_element_input() {
-        let input = ['a'];
-
-        assert_eq_slice(&input, None, None, None, &['a']);
-
-        assert_eq_slice(&input, Some(0), None, None, &['a']);
-        assert_eq_slice(&input, None, Some(0), None, &[]);
-        assert_eq_slice(&input, Some(0), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(0), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(0), Some(2), None, &['a']);
-
-        assert_eq_slice(&input, Some(-1), None, None, &['a']);
-        assert_eq_slice(&input, Some(-1), Some(-1), None, &[]);
-        assert_eq_slice(&input, Some(-1), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(-1), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(-1), Some(2), None, &['a']);
-        assert_eq_slice(&input, None, Some(-1), None, &[]);
-
-        assert_eq_slice(&input, Some(-2), None, None, &['a']);
-        assert_eq_slice(&input, Some(-2), Some(-1), None, &[]);
-        assert_eq_slice(&input, Some(-2), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(-2), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(-2), Some(2), None, &['a']);
-    }
-
-    #[test]
-    fn py_slice_nonnegative_indices() {
-        let input = ['a', 'b', 'c', 'd', 'e'];
-
-        assert_eq_slice(&input, None, Some(0), None, &[]);
-        assert_eq_slice(&input, None, Some(1), None, &['a']);
-        assert_eq_slice(&input, None, Some(4), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, None, Some(5), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, None, Some(6), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, None, None, None, &['a', 'b', 'c', 'd', 'e']);
-
-        assert_eq_slice(&input, Some(0), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(0), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(0), Some(4), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(0), Some(5), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(0), Some(6), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(0), None, None, &['a', 'b', 'c', 'd', 'e']);
-
-        assert_eq_slice(&input, Some(1), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(1), Some(1), None, &[]);
-        assert_eq_slice(&input, Some(1), Some(2), None, &['b']);
-        assert_eq_slice(&input, Some(1), Some(4), None, &['b', 'c', 'd']);
-        assert_eq_slice(&input, Some(1), Some(5), None, &['b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(1), Some(6), None, &['b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(1), None, None, &['b', 'c', 'd', 'e']);
-
-        assert_eq_slice(&input, Some(4), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(4), Some(4), None, &[]);
-        assert_eq_slice(&input, Some(4), Some(5), None, &['e']);
-        assert_eq_slice(&input, Some(4), Some(6), None, &['e']);
-        assert_eq_slice(&input, Some(4), None, None, &['e']);
-
-        assert_eq_slice(&input, Some(5), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(5), Some(5), None, &[]);
-        assert_eq_slice(&input, Some(5), Some(6), None, &[]);
-        assert_eq_slice(&input, Some(5), None, None, &[]);
-
-        assert_eq_slice(&input, Some(6), Some(0), None, &[]);
-        assert_eq_slice(&input, Some(6), Some(6), None, &[]);
-        assert_eq_slice(&input, Some(6), None, None, &[]);
-    }
-
-    #[test]
-    fn py_slice_negatice_indices() {
-        let input = ['a', 'b', 'c', 'd', 'e'];
-
-        assert_eq_slice(&input, Some(-6), None, None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-6), Some(-1), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-6), Some(-4), None, &['a']);
-        assert_eq_slice(&input, Some(-6), Some(-5), None, &[]);
-        assert_eq_slice(&input, Some(-6), Some(-6), None, &[]);
-        assert_eq_slice(&input, Some(-6), Some(-10), None, &[]);
-
-        assert_eq_slice(&input, Some(-5), None, None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-5), Some(-1), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-5), Some(-4), None, &['a']);
-        assert_eq_slice(&input, Some(-5), Some(-5), None, &[]);
-        assert_eq_slice(&input, Some(-5), Some(-6), None, &[]);
-        assert_eq_slice(&input, Some(-5), Some(-10), None, &[]);
-
-        assert_eq_slice(&input, Some(-4), None, None, &['b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-4), Some(-1), None, &['b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-4), Some(-3), None, &['b']);
-        assert_eq_slice(&input, Some(-4), Some(-4), None, &[]);
-        assert_eq_slice(&input, Some(-4), Some(-10), None, &[]);
-
-        assert_eq_slice(&input, Some(-1), None, None, &['e']);
-        assert_eq_slice(&input, Some(-1), Some(-1), None, &[]);
-        assert_eq_slice(&input, Some(-1), Some(-10), None, &[]);
-
-        assert_eq_slice(&input, None, Some(-1), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, None, Some(-4), None, &['a']);
-        assert_eq_slice(&input, None, Some(-5), None, &[]);
-        assert_eq_slice(&input, None, Some(-6), None, &[]);
-    }
-
-    #[test]
-    fn py_slice_mixed_positive_negative_indices() {
-        let input = ['a', 'b', 'c', 'd', 'e'];
-
-        assert_eq_slice(&input, Some(0), Some(-1), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(1), Some(-1), None, &['b', 'c', 'd']);
-        assert_eq_slice(&input, Some(3), Some(-1), None, &['d']);
-        assert_eq_slice(&input, Some(4), Some(-1), None, &[]);
-        assert_eq_slice(&input, Some(5), Some(-1), None, &[]);
-
-        assert_eq_slice(&input, Some(0), Some(-4), None, &['a']);
-        assert_eq_slice(&input, Some(1), Some(-4), None, &[]);
-        assert_eq_slice(&input, Some(3), Some(-4), None, &[]);
-
-        assert_eq_slice(&input, Some(0), Some(-5), None, &[]);
-        assert_eq_slice(&input, Some(1), Some(-5), None, &[]);
-        assert_eq_slice(&input, Some(3), Some(-5), None, &[]);
-
-        assert_eq_slice(&input, Some(0), Some(-6), None, &[]);
-        assert_eq_slice(&input, Some(1), Some(-6), None, &[]);
-
-        assert_eq_slice(&input, Some(-6), Some(6), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-6), Some(5), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-6), Some(4), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-6), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(-6), Some(0), None, &[]);
-
-        assert_eq_slice(&input, Some(-5), Some(6), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-5), Some(5), None, &['a', 'b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-5), Some(4), None, &['a', 'b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-5), Some(1), None, &['a']);
-        assert_eq_slice(&input, Some(-5), Some(0), None, &[]);
-
-        assert_eq_slice(&input, Some(-4), Some(6), None, &['b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-4), Some(5), None, &['b', 'c', 'd', 'e']);
-        assert_eq_slice(&input, Some(-4), Some(4), None, &['b', 'c', 'd']);
-        assert_eq_slice(&input, Some(-4), Some(2), None, &['b']);
-        assert_eq_slice(&input, Some(-4), Some(1), None, &[]);
-        assert_eq_slice(&input, Some(-4), Some(0), None, &[]);
-
-        assert_eq_slice(&input, Some(-1), Some(6), None, &['e']);
-        assert_eq_slice(&input, Some(-1), Some(5), None, &['e']);
-        assert_eq_slice(&input, Some(-1), Some(4), None, &[]);
-        assert_eq_slice(&input, Some(-1), Some(1), None, &[]);
-    }
-
-    #[test]
-    fn py_slice_step_forward() {
-        // indices:   0    1    2    3    4    5    6
-        let input = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
-
-        // Step size zero is invalid:
-        assert!(matches!(
-            input.py_slice(None, None, Some(0)),
-            Err(StepSizeZeroError)
-        ));
-        assert!(matches!(
-            input.py_slice(Some(0), Some(5), Some(0)),
-            Err(StepSizeZeroError)
-        ));
-        assert!(matches!(
-            input.py_slice(Some(0), Some(0), Some(0)),
-            Err(StepSizeZeroError)
-        ));
-
-        assert_eq_slice(&input, Some(0), Some(8), Some(2), &['a', 'c', 'e', 'g']);
-        assert_eq_slice(&input, Some(0), Some(7), Some(2), &['a', 'c', 'e', 'g']);
-        assert_eq_slice(&input, Some(0), Some(6), Some(2), &['a', 'c', 'e']);
-        assert_eq_slice(&input, Some(0), Some(5), Some(2), &['a', 'c', 'e']);
-        assert_eq_slice(&input, Some(0), Some(4), Some(2), &['a', 'c']);
-        assert_eq_slice(&input, Some(0), Some(3), Some(2), &['a', 'c']);
-        assert_eq_slice(&input, Some(0), Some(2), Some(2), &['a']);
-        assert_eq_slice(&input, Some(0), Some(1), Some(2), &['a']);
-        assert_eq_slice(&input, Some(0), Some(0), Some(2), &[]);
-        assert_eq_slice(&input, Some(1), Some(5), Some(2), &['b', 'd']);
-
-        assert_eq_slice(&input, Some(0), Some(7), Some(3), &['a', 'd', 'g']);
-        assert_eq_slice(&input, Some(0), Some(6), Some(3), &['a', 'd']);
-
-        assert_eq_slice(&input, Some(0), None, Some(10), &['a']);
-    }
-
-    #[test]
-    fn py_slice_step_backward() {
-        // indices:   0    1    2    3    4    5    6
-        let input = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
-
-        assert_eq_slice(&input, Some(7), Some(0), Some(-2), &['g', 'e', 'c']);
-        assert_eq_slice(&input, Some(6), Some(0), Some(-2), &['g', 'e', 'c']);
-        assert_eq_slice(&input, Some(5), Some(0), Some(-2), &['f', 'd', 'b']);
-        assert_eq_slice(&input, Some(4), Some(0), Some(-2), &['e', 'c']);
-        assert_eq_slice(&input, Some(3), Some(0), Some(-2), &['d', 'b']);
-        assert_eq_slice(&input, Some(2), Some(0), Some(-2), &['c']);
-        assert_eq_slice(&input, Some(1), Some(0), Some(-2), &['b']);
-        assert_eq_slice(&input, Some(0), Some(0), Some(-2), &[]);
-
-        assert_eq_slice(&input, Some(7), None, Some(-2), &['g', 'e', 'c', 'a']);
-        assert_eq_slice(&input, None, None, Some(-2), &['g', 'e', 'c', 'a']);
-        assert_eq_slice(&input, None, Some(0), Some(-2), &['g', 'e', 'c']);
-
-        assert_eq_slice(&input, Some(5), Some(1), Some(-2), &['f', 'd']);
-        assert_eq_slice(&input, Some(5), Some(2), Some(-2), &['f', 'd']);
-        assert_eq_slice(&input, Some(5), Some(3), Some(-2), &['f']);
-        assert_eq_slice(&input, Some(5), Some(4), Some(-2), &['f']);
-        assert_eq_slice(&input, Some(5), Some(5), Some(-2), &[]);
-
-        assert_eq_slice(&input, Some(6), None, Some(-3), &['g', 'd', 'a']);
-        assert_eq_slice(&input, Some(6), Some(0), Some(-3), &['g', 'd']);
-
-        assert_eq_slice(&input, Some(7), None, Some(-10), &['g']);
-
-        assert_eq_slice(&input, Some(-6), Some(-9), Some(-1), &['b', 'a']);
-        assert_eq_slice(&input, Some(-6), Some(-8), Some(-1), &['b', 'a']);
-        assert_eq_slice(&input, Some(-6), Some(-7), Some(-1), &['b']);
-        assert_eq_slice(&input, Some(-6), Some(-6), Some(-1), &[]);
-
-        assert_eq_slice(&input, Some(-7), Some(-9), Some(-1), &['a']);
-
-        assert_eq_slice(&input, Some(-8), Some(-9), Some(-1), &[]);
-        assert_eq_slice(&input, Some(-9), Some(-9), Some(-1), &[]);
-
-        assert_eq_slice(&input, Some(-6), Some(-2), Some(-1), &[]);
-        assert_eq_slice(&input, Some(-9), Some(-6), Some(-1), &[]);
+        // but i64::MIN +1 is:
+        assert_eq!(
+            iter.clone().python_subscript(i64::MIN + 1),
+            Some(2u64.pow(63) + 1)
+        );
     }
 }

crates/red_knot_server/src/edit.rs

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

crates/red_knot_server/src/edit/range.rs

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

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

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

crates/red_knot_test/src/assertion.rs

@@ -40,7 +40,7 @@ use ruff_db::files::File;
 use ruff_db::parsed::parsed_module;
 use ruff_db::source::{line_index, source_text, SourceText};
 use ruff_python_trivia::CommentRanges;
-use ruff_source_file::{LineIndex, OneIndexed};
+use ruff_source_file::{LineIndex, Locator, OneIndexed};
 use ruff_text_size::{Ranged, TextRange};
 use smallvec::SmallVec;
 use std::ops::Deref;
@@ -67,6 +67,10 @@ impl InlineFileAssertions {
         }
     }
 
+    fn locator(&self) -> Locator {
+        Locator::with_index(&self.source, self.lines.clone())
+    }
+
     fn line_number(&self, range: &impl Ranged) -> OneIndexed {
         self.lines.line_index(range.start())
     }
@@ -127,9 +131,10 @@ impl<'a> Iterator for AssertionWithRangeIterator<'a> {
     type Item = AssertionWithRange<'a>;
 
     fn next(&mut self) -> Option<Self::Item> {
+        let locator = self.file_assertions.locator();
         loop {
             let inner_next = self.inner.next()?;
-            let comment = &self.file_assertions.source[inner_next];
+            let comment = locator.slice(inner_next);
             if let Some(assertion) = Assertion::from_comment(comment) {
                 return Some(AssertionWithRange(assertion, inner_next));
             };

crates/red_knot_test/src/diagnostic.rs

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

crates/red_knot_test/src/lib.rs

@@ -1,7 +1,6 @@
 use colored::Colorize;
 use parser as test_parser;
 use red_knot_python_semantic::types::check_types;
-use ruff_db::diagnostic::{Diagnostic, ParseDiagnostic};
 use ruff_db::files::{system_path_to_file, File, Files};
 use ruff_db::parsed::parsed_module;
 use ruff_db::system::{DbWithTestSystem, SystemPathBuf};
@@ -88,24 +87,16 @@ fn run_test(db: &mut db::Db, test: &parser::MarkdownTest) -> Result<(), Failures
         .filter_map(|test_file| {
             let parsed = parsed_module(db, test_file.file);
 
-            let mut diagnostics: Vec<Box<_>> = parsed
-                .errors()
-                .iter()
-                .cloned()
-                .map(|error| {
-                    let diagnostic: Box<dyn Diagnostic> =
-                        Box::new(ParseDiagnostic::new(test_file.file, error));
-                    diagnostic
-                })
-                .collect();
+            // TODO allow testing against code with syntax errors
+            assert!(
+                parsed.errors().is_empty(),
+                "Python syntax errors in {}, {}: {:?}",
+                test.name(),
+                test_file.file.path(db),
+                parsed.errors()
+            );
 
-            let type_diagnostics = check_types(db, test_file.file);
-            diagnostics.extend(type_diagnostics.into_iter().map(|diagnostic| {
-                let diagnostic: Box<dyn Diagnostic> = Box::new((*diagnostic).clone());
-                diagnostic
-            }));
-
-            match matcher::match_file(db, test_file.file, diagnostics) {
+            match matcher::match_file(db, test_file.file, check_types(db, test_file.file)) {
                 Ok(()) => None,
                 Err(line_failures) => Some(FileFailures {
                     backtick_offset: test_file.backtick_offset,

crates/red_knot_test/src/matcher.rs

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

crates/red_knot_test/src/parser.rs

@@ -148,7 +148,7 @@ static HEADER_RE: LazyLock<Regex> =
 /// Matches a code block fenced by triple backticks, possibly with language and `key=val`
 /// configuration items following the opening backticks (in the "tag string" of the code block).
 static CODE_RE: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r"^```(?<lang>(?-u:\w)+)?(?<config>(?: +\S+)*)\s*\n(?<code>(?:.|\n)*?)\n?```\s*\n?")
+    Regex::new(r"^```(?<lang>(?-u:\w)+)?(?<config>(?: +\S+)*)\s*\n(?<code>(?:.|\n)*?)\n?```\s*\n")
         .unwrap()
 });
 
@@ -421,31 +421,6 @@ mod tests {
         assert_eq!(file.code, "x = 1");
     }
 
-    #[test]
-    fn no_new_line_at_eof() {
-        let source = dedent(
-            "
-            ```py
-            x = 1
-            ```",
-        );
-        let mf = super::parse("file.md", &source).unwrap();
-
-        let [test] = &mf.tests().collect::<Vec<_>>()[..] else {
-            panic!("expected one test");
-        };
-
-        assert_eq!(test.name(), "file.md");
-
-        let [file] = test.files().collect::<Vec<_>>()[..] else {
-            panic!("expected one file");
-        };
-
-        assert_eq!(file.path, "test.py");
-        assert_eq!(file.lang, "py");
-        assert_eq!(file.code, "x = 1");
-    }
-
     #[test]
     fn multiple_tests() {
         let source = dedent(

crates/red_knot_vendored/vendor/typeshed/source_commit.txt

@@ -1 +1 @@
-d262beb07502cda412db2179fb406d45d1a9486f
+a871efd90ca2734b3341dde98cffab66f3e08cee