New KnownInstanceType

Co-authored-by: Micha Reiser <micha@reiser.io>

.github/workflows/ci.yaml

@@ -284,6 +284,10 @@ jobs:
         run: cargo insta test --all-features --unreferenced reject --test-runner nextest
       - name: Dogfood ty on py-fuzzer
         run: uv run --project=./python/py-fuzzer cargo run -p ty check --project=./python/py-fuzzer
+      - name: Dogfood ty on the scripts directory
+        run: uv run --project=./scripts cargo run -p ty check --project=./scripts
+      - name: Dogfood ty on ty_benchmark
+        run: uv run --project=./scripts/ty_benchmark cargo run -p ty check --project=./scripts/ty_benchmark
       # Check for broken links in the documentation.
       - run: cargo doc --all --no-deps
         env:

.vscode/settings.json

@@ -5,5 +5,6 @@
     "rust-analyzer.check.command": "clippy",
     "search.exclude": {
         "**/*.snap": true
-    }
+    },
+    "ty.diagnosticMode": "openFilesOnly"
 }

crates/ty/docs/rules.md

@@ -39,7 +39,7 @@ def test(): -> "int":
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-non-callable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L126" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L127" target="_blank">View source</a>
 </small>
 
 
@@ -63,7 +63,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-argument-forms" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L170" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L171" target="_blank">View source</a>
 </small>
 
 
@@ -95,7 +95,7 @@ f(int)  # error
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-declarations" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L196" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L197" target="_blank">View source</a>
 </small>
 
 
@@ -126,7 +126,7 @@ a = 1
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-metaclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L221" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L222" target="_blank">View source</a>
 </small>
 
 
@@ -158,7 +158,7 @@ class C(A, B): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20cyclic-class-definition" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L247" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L248" target="_blank">View source</a>
 </small>
 
 
@@ -190,7 +190,7 @@ class B(A): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20duplicate-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L312" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L313" target="_blank">View source</a>
 </small>
 
 
@@ -217,7 +217,7 @@ class B(A, A): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.12">0.0.1-alpha.12</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20duplicate-kw-only" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L333" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L334" target="_blank">View source</a>
 </small>
 
 
@@ -329,7 +329,7 @@ def test(): -> "Literal[5]":
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20inconsistent-mro" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L537" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L538" target="_blank">View source</a>
 </small>
 
 
@@ -359,7 +359,7 @@ class C(A, B): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20index-out-of-bounds" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L561" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L562" target="_blank">View source</a>
 </small>
 
 
@@ -385,7 +385,7 @@ t[3]  # IndexError: tuple index out of range
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.12">0.0.1-alpha.12</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20instance-layout-conflict" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L365" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L366" target="_blank">View source</a>
 </small>
 
 
@@ -474,7 +474,7 @@ an atypical memory layout.
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-argument-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L615" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L616" target="_blank">View source</a>
 </small>
 
 
@@ -501,7 +501,7 @@ func("foo")  # error: [invalid-argument-type]
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-assignment" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L655" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L656" target="_blank">View source</a>
 </small>
 
 
@@ -529,7 +529,7 @@ a: int = ''
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-attribute-access" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1814" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1815" target="_blank">View source</a>
 </small>
 
 
@@ -563,7 +563,7 @@ C.instance_var = 3  # error: Cannot assign to instance variable
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.19">0.0.1-alpha.19</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-await" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L677" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L678" target="_blank">View source</a>
 </small>
 
 
@@ -599,7 +599,7 @@ asyncio.run(main())
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L707" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L708" target="_blank">View source</a>
 </small>
 
 
@@ -623,7 +623,7 @@ class A(42): ...  # error: [invalid-base]
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-context-manager" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L758" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L759" target="_blank">View source</a>
 </small>
 
 
@@ -650,7 +650,7 @@ with 1:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-declaration" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L779" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L780" target="_blank">View source</a>
 </small>
 
 
@@ -679,7 +679,7 @@ a: str
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-exception-caught" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L802" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L803" target="_blank">View source</a>
 </small>
 
 
@@ -723,7 +723,7 @@ except ZeroDivisionError:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-generic-class" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L838" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L839" target="_blank">View source</a>
 </small>
 
 
@@ -756,7 +756,7 @@ class C[U](Generic[T]): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.17">0.0.1-alpha.17</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-key" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L582" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L583" target="_blank">View source</a>
 </small>
 
 
@@ -795,7 +795,7 @@ carol = Person(name="Carol", age=25)  # typo!
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-legacy-type-variable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L864" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L865" target="_blank">View source</a>
 </small>
 
 
@@ -830,7 +830,7 @@ def f(t: TypeVar("U")): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-metaclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L961" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L962" target="_blank">View source</a>
 </small>
 
 
@@ -864,7 +864,7 @@ class B(metaclass=f): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-method-override" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1942" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1943" target="_blank">View source</a>
 </small>
 
 
@@ -950,7 +950,7 @@ and `__ne__` methods accept `object` as their second argument.
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.19">0.0.1-alpha.19</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-named-tuple" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L511" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L512" target="_blank">View source</a>
 </small>
 
 
@@ -982,7 +982,7 @@ TypeError: can only inherit from a NamedTuple type and Generic
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/1.0.0">1.0.0</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-newtype" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L937" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L938" target="_blank">View source</a>
 </small>
 
 
@@ -1012,7 +1012,7 @@ Baz = NewType("Baz", int | str)  # error: invalid base for `typing.NewType`
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-overload" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L988" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L989" target="_blank">View source</a>
 </small>
 
 
@@ -1062,7 +1062,7 @@ def foo(x: int) -> int: ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-parameter-default" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1087" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1088" target="_blank">View source</a>
 </small>
 
 
@@ -1088,7 +1088,7 @@ def f(a: int = ''): ...
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-paramspec" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L892" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L893" target="_blank">View source</a>
 </small>
 
 
@@ -1119,7 +1119,7 @@ P2 = ParamSpec("S2")  # error: ParamSpec name must match the variable it's assig
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-protocol" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L447" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L448" target="_blank">View source</a>
 </small>
 
 
@@ -1153,7 +1153,7 @@ TypeError: Protocols can only inherit from other protocols, got <class 'int'>
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-raise" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1107" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1108" target="_blank">View source</a>
 </small>
 
 
@@ -1202,7 +1202,7 @@ def g():
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-return-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L636" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L637" target="_blank">View source</a>
 </small>
 
 
@@ -1227,7 +1227,7 @@ def func() -> int:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-super-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1150" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1151" target="_blank">View source</a>
 </small>
 
 
@@ -1285,7 +1285,7 @@ TODO #14889
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.6">0.0.1-alpha.6</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-alias-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L916" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L917" target="_blank">View source</a>
 </small>
 
 
@@ -1312,7 +1312,7 @@ NewAlias = TypeAliasType(get_name(), int)        # error: TypeAliasType name mus
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-checking-constant" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1189" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1190" target="_blank">View source</a>
 </small>
 
 
@@ -1342,7 +1342,7 @@ TYPE_CHECKING = ''
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-form" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1213" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1214" target="_blank">View source</a>
 </small>
 
 
@@ -1372,7 +1372,7 @@ b: Annotated[int]  # `Annotated` expects at least two arguments
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.11">0.0.1-alpha.11</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-guard-call" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1265" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1266" target="_blank">View source</a>
 </small>
 
 
@@ -1406,7 +1406,7 @@ f(10)  # Error
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.11">0.0.1-alpha.11</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-guard-definition" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1237" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1238" target="_blank">View source</a>
 </small>
 
 
@@ -1440,7 +1440,7 @@ class C:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-variable-constraints" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1293" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1294" target="_blank">View source</a>
 </small>
 
 
@@ -1475,7 +1475,7 @@ T = TypeVar('T', bound=str)  # valid bound TypeVar
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20missing-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1322" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1323" target="_blank">View source</a>
 </small>
 
 
@@ -1500,7 +1500,7 @@ func()  # TypeError: func() missing 1 required positional argument: 'x'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20missing-typed-dict-key" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1915" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1916" target="_blank">View source</a>
 </small>
 
 
@@ -1533,7 +1533,7 @@ alice["age"]  # KeyError
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20no-matching-overload" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1341" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1342" target="_blank">View source</a>
 </small>
 
 
@@ -1562,7 +1562,7 @@ func("string")  # error: [no-matching-overload]
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20non-subscriptable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1364" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1365" target="_blank">View source</a>
 </small>
 
 
@@ -1586,7 +1586,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20not-iterable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1382" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1383" target="_blank">View source</a>
 </small>
 
 
@@ -1612,7 +1612,7 @@ for i in 34:  # TypeError: 'int' object is not iterable
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20parameter-already-assigned" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1433" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1434" target="_blank">View source</a>
 </small>
 
 
@@ -1639,7 +1639,7 @@ f(1, x=2)  # Error raised here
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20positional-only-parameter-as-kwarg" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1668" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1669" target="_blank">View source</a>
 </small>
 
 
@@ -1697,7 +1697,7 @@ def test(): -> "int":
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20static-assert-error" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1790" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1791" target="_blank">View source</a>
 </small>
 
 
@@ -1727,7 +1727,7 @@ static_assert(int(2.0 * 3.0) == 6)  # error: does not have a statically known tr
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20subclass-of-final-class" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1524" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1525" target="_blank">View source</a>
 </small>
 
 
@@ -1756,7 +1756,7 @@ class B(A): ...  # Error raised here
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20too-many-positional-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1569" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1570" target="_blank">View source</a>
 </small>
 
 
@@ -1783,7 +1783,7 @@ f("foo")  # Error raised here
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20type-assertion-failure" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1547" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1548" target="_blank">View source</a>
 </small>
 
 
@@ -1811,7 +1811,7 @@ def _(x: int):
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unavailable-implicit-super-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1590" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1591" target="_blank">View source</a>
 </small>
 
 
@@ -1857,7 +1857,7 @@ class A:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unknown-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1647" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1648" target="_blank">View source</a>
 </small>
 
 
@@ -1884,7 +1884,7 @@ f(x=1, y=2)  # Error raised here
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-attribute" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1689" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1690" target="_blank">View source</a>
 </small>
 
 
@@ -1912,7 +1912,7 @@ A().foo  # AttributeError: 'A' object has no attribute 'foo'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-import" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1711" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1712" target="_blank">View source</a>
 </small>
 
 
@@ -1937,7 +1937,7 @@ import foo  # ModuleNotFoundError: No module named 'foo'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-reference" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1730" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1731" target="_blank">View source</a>
 </small>
 
 
@@ -1962,7 +1962,7 @@ print(x)  # NameError: name 'x' is not defined
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-bool-conversion" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1402" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1403" target="_blank">View source</a>
 </small>
 
 
@@ -1999,7 +1999,7 @@ b1 < b2 < b1  # exception raised here
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-operator" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1749" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1750" target="_blank">View source</a>
 </small>
 
 
@@ -2027,7 +2027,7 @@ A() + A()  # TypeError: unsupported operand type(s) for +: 'A' and 'A'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20zero-stepsize-in-slice" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1771" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1772" target="_blank">View source</a>
 </small>
 
 
@@ -2052,7 +2052,7 @@ l[1:10:0]  # ValueError: slice step cannot be zero
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20ambiguous-protocol-member" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L476" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L477" target="_blank">View source</a>
 </small>
 
 
@@ -2093,7 +2093,7 @@ class SubProto(BaseProto, Protocol):
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.16">0.0.1-alpha.16</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20deprecated" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L291" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L292" target="_blank">View source</a>
 </small>
 
 
@@ -2181,7 +2181,7 @@ a = 20 / 0  # type: ignore
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-attribute" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1454" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1455" target="_blank">View source</a>
 </small>
 
 
@@ -2209,7 +2209,7 @@ A.c  # AttributeError: type object 'A' has no attribute 'c'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-implicit-call" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L144" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L145" target="_blank">View source</a>
 </small>
 
 
@@ -2241,7 +2241,7 @@ A()[0]  # TypeError: 'A' object is not subscriptable
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-import" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1476" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1477" target="_blank">View source</a>
 </small>
 
 
@@ -2273,7 +2273,7 @@ from module import a  # ImportError: cannot import name 'a' from 'module'
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20redundant-cast" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1842" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1843" target="_blank">View source</a>
 </small>
 
 
@@ -2300,7 +2300,7 @@ cast(int, f())  # Redundant
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20undefined-reveal" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1629" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1630" target="_blank">View source</a>
 </small>
 
 
@@ -2324,7 +2324,7 @@ reveal_type(1)  # NameError: name 'reveal_type' is not defined
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.15">0.0.1-alpha.15</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-global" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1863" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1864" target="_blank">View source</a>
 </small>
 
 
@@ -2382,7 +2382,7 @@ def g():
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.7">0.0.1-alpha.7</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L725" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L726" target="_blank">View source</a>
 </small>
 
 
@@ -2421,7 +2421,7 @@ class D(C): ...  # error: [unsupported-base]
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20useless-overload-body" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1031" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1032" target="_blank">View source</a>
 </small>
 
 
@@ -2484,7 +2484,7 @@ def foo(x: int | str) -> int | str:
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'ignore'."><code>ignore</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20division-by-zero" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L273" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L274" target="_blank">View source</a>
 </small>
 
 
@@ -2508,7 +2508,7 @@ Dividing by zero raises a `ZeroDivisionError` at runtime.
 Default level: <a href="../rules.md#rule-levels" title="This lint has a default level of 'ignore'."><code>ignore</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-unresolved-reference" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1502" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1503" target="_blank">View source</a>
 </small>
 
 

crates/ty_ide/src/inlay_hints.rs

@@ -6,8 +6,8 @@ use ruff_db::parsed::parsed_module;
 use ruff_python_ast::visitor::source_order::{self, SourceOrderVisitor, TraversalSignal};
 use ruff_python_ast::{AnyNodeRef, ArgOrKeyword, Expr, ExprUnaryOp, Stmt, UnaryOp};
 use ruff_text_size::{Ranged, TextRange, TextSize};
-use ty_python_semantic::types::Type;
 use ty_python_semantic::types::ide_support::inlay_hint_call_argument_details;
+use ty_python_semantic::types::{Type, TypeDetail};
 use ty_python_semantic::{HasType, SemanticModel};
 
 #[derive(Debug, Clone)]
@@ -15,10 +15,12 @@ pub struct InlayHint {
     pub position: TextSize,
     pub kind: InlayHintKind,
     pub label: InlayHintLabel,
+    pub text_edits: Vec<InlayHintTextEdit>,
 }
 
 impl InlayHint {
-    fn variable_type(position: TextSize, ty: Type, db: &dyn Db) -> Self {
+    fn variable_type(expr: &Expr, ty: Type, db: &dyn Db, allow_edits: bool) -> Self {
+        let position = expr.range().end();
         // Render the type to a string, and get subspans for all the types that make it up
         let details = ty.display(db).to_string_parts();
 
@@ -34,7 +36,7 @@ impl InlayHint {
         let mut label_parts = vec![": ".into()];
         for (target, detail) in details.targets.iter().zip(&details.details) {
             match detail {
-                ty_python_semantic::types::TypeDetail::Type(ty) => {
+                TypeDetail::Type(ty) => {
                     let start = target.start().to_usize();
                     let end = target.end().to_usize();
                     // If we skipped over some bytes, push them with no target
@@ -50,9 +52,9 @@ impl InlayHint {
                         offset = end;
                     }
                 }
-                ty_python_semantic::types::TypeDetail::SignatureStart
-                | ty_python_semantic::types::TypeDetail::SignatureEnd
-                | ty_python_semantic::types::TypeDetail::Parameter(_) => {
+                TypeDetail::SignatureStart
+                | TypeDetail::SignatureEnd
+                | TypeDetail::Parameter(_) => {
                     // Don't care about these
                 }
             }
@@ -62,10 +64,20 @@ impl InlayHint {
             label_parts.push(details.label[offset..details.label.len()].into());
         }
 
+        let text_edits = if details.is_valid_syntax && allow_edits {
+            vec![InlayHintTextEdit {
+                range: TextRange::new(position, position),
+                new_text: format!(": {}", details.label),
+            }]
+        } else {
+            vec![]
+        };
+
         Self {
             position,
             kind: InlayHintKind::Type,
             label: InlayHintLabel { parts: label_parts },
+            text_edits,
         }
     }
 
@@ -83,6 +95,7 @@ impl InlayHint {
             position,
             kind: InlayHintKind::CallArgumentName,
             label: InlayHintLabel { parts: label_parts },
+            text_edits: vec![],
         }
     }
 
@@ -175,6 +188,12 @@ impl From<&str> for InlayHintLabelPart {
     }
 }
 
+#[derive(Debug, Clone)]
+pub struct InlayHintTextEdit {
+    pub range: TextRange,
+    pub new_text: String,
+}
+
 pub fn inlay_hints(
     db: &dyn Db,
     file: File,
@@ -234,6 +253,7 @@ struct InlayHintVisitor<'a, 'db> {
     in_assignment: bool,
     range: TextRange,
     settings: &'a InlayHintSettings,
+    in_no_edits_allowed: bool,
 }
 
 impl<'a, 'db> InlayHintVisitor<'a, 'db> {
@@ -245,15 +265,16 @@ impl<'a, 'db> InlayHintVisitor<'a, 'db> {
             in_assignment: false,
             range,
             settings,
+            in_no_edits_allowed: false,
         }
     }
 
-    fn add_type_hint(&mut self, position: TextSize, ty: Type<'db>) {
+    fn add_type_hint(&mut self, expr: &Expr, ty: Type<'db>, allow_edits: bool) {
         if !self.settings.variable_types {
             return;
         }
 
-        let inlay_hint = InlayHint::variable_type(position, ty, self.db);
+        let inlay_hint = InlayHint::variable_type(expr, ty, self.db, allow_edits);
 
         self.hints.push(inlay_hint);
     }
@@ -297,9 +318,13 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
         match stmt {
             Stmt::Assign(assign) => {
                 self.in_assignment = !type_hint_is_excessive_for_expr(&assign.value);
+                if !annotations_are_valid_syntax(assign) {
+                    self.in_no_edits_allowed = true;
+                }
                 for target in &assign.targets {
                     self.visit_expr(target);
                 }
+                self.in_no_edits_allowed = false;
                 self.in_assignment = false;
 
                 self.visit_expr(&assign.value);
@@ -325,7 +350,7 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
                 if self.in_assignment {
                     if name.ctx.is_store() {
                         let ty = expr.inferred_type(&self.model);
-                        self.add_type_hint(expr.range().end(), ty);
+                        self.add_type_hint(expr, ty, !self.in_no_edits_allowed);
                     }
                 }
                 source_order::walk_expr(self, expr);
@@ -334,7 +359,7 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
                 if self.in_assignment {
                     if attribute.ctx.is_store() {
                         let ty = expr.inferred_type(&self.model);
-                        self.add_type_hint(expr.range().end(), ty);
+                        self.add_type_hint(expr, ty, !self.in_no_edits_allowed);
                     }
                 }
                 source_order::walk_expr(self, expr);
@@ -420,6 +445,22 @@ fn type_hint_is_excessive_for_expr(expr: &Expr) -> bool {
     }
 }
 
+fn annotations_are_valid_syntax(stmt_assign: &ruff_python_ast::StmtAssign) -> bool {
+    if stmt_assign.targets.len() > 1 {
+        return false;
+    }
+
+    if stmt_assign
+        .targets
+        .iter()
+        .any(|target| matches!(target, Expr::Tuple(_)))
+    {
+        return false;
+    }
+
+    true
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -427,6 +468,7 @@ mod tests {
     use crate::NavigationTarget;
     use crate::tests::IntoDiagnostic;
     use insta::{assert_snapshot, internals::SettingsBindDropGuard};
+    use itertools::Itertools;
     use ruff_db::{
         diagnostic::{
             Annotation, Diagnostic, DiagnosticFormat, DiagnosticId, DisplayDiagnosticConfig,
@@ -517,12 +559,15 @@ mod tests {
         fn inlay_hints_with_settings(&mut self, settings: &InlayHintSettings) -> String {
             let hints = inlay_hints(&self.db, self.file, self.range, settings);
 
-            let mut buf = source_text(&self.db, self.file).as_str().to_string();
+            let mut inlay_hint_buf = source_text(&self.db, self.file).as_str().to_string();
+            let mut text_edit_buf = inlay_hint_buf.clone();
 
             let mut tbd_diagnostics = Vec::new();
 
             let mut offset = 0;
 
+            let mut edit_offset = 0;
+
             for hint in hints {
                 let end_position = hint.position.to_usize() + offset;
                 let mut hint_str = "[".to_string();
@@ -538,36 +583,65 @@ mod tests {
                     hint_str.push_str(part.text());
                 }
 
+                for edit in hint.text_edits {
+                    let start = edit.range.start().to_usize() + edit_offset;
+                    let end = edit.range.end().to_usize() + edit_offset;
+
+                    text_edit_buf.replace_range(start..end, &edit.new_text);
+
+                    if start == end {
+                        edit_offset += edit.new_text.len();
+                    } else {
+                        edit_offset += edit.new_text.len() - edit.range.len().to_usize();
+                    }
+                }
+
                 hint_str.push(']');
                 offset += hint_str.len();
 
-                buf.insert_str(end_position, &hint_str);
+                inlay_hint_buf.insert_str(end_position, &hint_str);
             }
 
-            self.db.write_file("main2.py", &buf).unwrap();
+            self.db.write_file("main2.py", &inlay_hint_buf).unwrap();
             let inlayed_file =
                 system_path_to_file(&self.db, "main2.py").expect("newly written file to existing");
 
-            let diagnostics = tbd_diagnostics.into_iter().map(|(label_range, target)| {
+            let location_diagnostics = tbd_diagnostics.into_iter().map(|(label_range, target)| {
                 InlayHintLocationDiagnostic::new(FileRange::new(inlayed_file, label_range), &target)
             });
 
-            let mut rendered_diagnostics = self.render_diagnostics(diagnostics);
+            let mut rendered_diagnostics = location_diagnostics
+                .map(|diagnostic| self.render_diagnostic(diagnostic))
+                .join("");
 
             if !rendered_diagnostics.is_empty() {
                 rendered_diagnostics = format!(
                     "{}{}",
                     crate::MarkupKind::PlainText.horizontal_line(),
                     rendered_diagnostics
+                        .strip_suffix("\n")
+                        .unwrap_or(&rendered_diagnostics)
                 );
             }
 
-            format!("{buf}{rendered_diagnostics}",)
+            let rendered_edit_diagnostic = if edit_offset != 0 {
+                let edit_diagnostic = InlayHintEditDiagnostic::new(text_edit_buf);
+                let text_edit_buf = self.render_diagnostic(edit_diagnostic);
+
+                format!(
+                    "{}{}",
+                    crate::MarkupKind::PlainText.horizontal_line(),
+                    text_edit_buf
+                )
+            } else {
+                String::new()
+            };
+
+            format!("{inlay_hint_buf}{rendered_diagnostics}{rendered_edit_diagnostic}",)
         }
 
-        fn render_diagnostics<I, D>(&self, diagnostics: I) -> String
+        fn render_diagnostic<D>(&self, diagnostic: D) -> String
         where
-            I: IntoIterator<Item = D>,
             D: IntoDiagnostic,
         {
             use std::fmt::Write;
@@ -578,10 +652,8 @@ mod tests {
                 .color(false)
                 .format(DiagnosticFormat::Full);
 
-            for diagnostic in diagnostics {
-                let diag = diagnostic.into_diagnostic();
-                write!(buf, "{}", diag.display(&self.db, &config)).unwrap();
-            }
+            let diag = diagnostic.into_diagnostic();
+            write!(buf, "{}", diag.display(&self.db, &config)).unwrap();
 
             buf
         }
@@ -728,6 +800,20 @@ mod tests {
         10 | bb[: Literal[b"foo"]] = aa
            |              ^^^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+
+        x = 1
+        y: Literal[1] = x
+        z: int = i(1)
+        w: int = z
+        aa = b'foo'
+        bb: Literal[b"foo"] = aa
         "#);
     }
 
@@ -1321,6 +1407,20 @@ mod tests {
         10 | w[: tuple[int, str]] = z
            |                ^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+        def s(x: str, /) -> str:
+            return x
+
+        x = (1, 'abc')
+        y: tuple[Literal[1], Literal["abc"]] = x
+        z: tuple[int, str] = (i(1), s('abc'))
+        w: tuple[int, str] = z
         "#);
     }
 
@@ -1654,6 +1754,18 @@ mod tests {
         8 | w[: int] = z
           |     ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+
+        x: int = 1
+        y: Literal[1] = x
+        z: int = i(1)
+        w: int = z
         "#);
     }
 
@@ -1691,6 +1803,15 @@ mod tests {
           |     ^^^
         5 | z = x
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+        x: int = i(1)
+        z = x
         "#);
     }
 
@@ -1810,6 +1931,18 @@ mod tests {
         8 | a.y[: int] = int(3)
           |       ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class A:
+            def __init__(self, y):
+                self.x: int = int(1)
+                self.y: Unknown = y
+
+        a: A = A(2)
+        a.y: int = int(3)
         "#);
     }
 
@@ -2640,6 +2773,22 @@ mod tests {
         12 | k[: list[Unknown | int | float]] = [-1, -2.0]
            |                          ^^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        a: list[Unknown | int] = [1, 2]
+        b: list[Unknown | float] = [1.0, 2.0]
+        c: list[Unknown | bool] = [True, False]
+        d: list[Unknown | None] = [None, None]
+        e: list[Unknown | str] = ["hel", "lo"]
+        f: list[Unknown | str] = ['the', 're']
+        g: list[Unknown | str] = [f"{ft}", f"{ft}"]
+        h: list[Unknown | Template] = [t"wow %d", t"wow %d"]
+        i: list[Unknown | bytes] = [b'/x01', b'/x02']
+        j: list[Unknown | int | float] = [+1, +2.0]
+        k: list[Unknown | int | float] = [-1, -2.0]
         "#);
     }
 
@@ -2811,6 +2960,19 @@ mod tests {
         9 | c[: MyClass], d[: MyClass] = (MyClass(), MyClass())
           |                   ^^^^^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+
+        x: MyClass = MyClass()
+        y: tuple[MyClass, MyClass] = (MyClass(), MyClass())
+        a, b = MyClass(), MyClass()
+        c, d = (MyClass(), MyClass())
         "#);
     }
 
@@ -3681,6 +3843,20 @@ mod tests {
         10 | c[: MyClass[Unknown | int, str]], d[: MyClass[Unknown | int, str]] = (MyClass([x=][42], [y=]("a", "b")), MyClass([x=][42], [y=]("a", "…
            |                                                                                                                             ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class MyClass[T, U]:
+            def __init__(self, x: list[T], y: tuple[U, U]):
+                self.x = x
+                self.y = y
+
+        x: MyClass[Unknown | int, str] = MyClass([42], ("a", "b"))
+        y: tuple[MyClass[Unknown | int, str], MyClass[Unknown | int, str]] = (MyClass([42], ("a", "b")), MyClass([42], ("a", "b")))
+        a, b = MyClass([42], ("a", "b")), MyClass([42], ("a", "b"))
+        c, d = (MyClass([42], ("a", "b")), MyClass([42], ("a", "b")))
         "#);
     }
 
@@ -3836,6 +4012,20 @@ mod tests {
         10 | foo([x=]val.y)
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+                self.y: int = 2
+        val: MyClass = MyClass()
+
+        foo(val.x)
+        foo(val.y)
         ");
     }
 
@@ -3901,6 +4091,20 @@ mod tests {
         10 | foo([x=]x.y)
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+                self.y: int = 2
+        x: MyClass = MyClass()
+
+        foo(x.x)
+        foo(x.y)
         ");
     }
 
@@ -3969,6 +4173,22 @@ mod tests {
         12 | foo([x=]val.y())
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+            def x() -> int:
+                return 1
+            def y() -> int:
+                return 2
+        val: MyClass = MyClass()
+
+        foo(val.x())
+        foo(val.y())
         ");
     }
 
@@ -4043,6 +4263,24 @@ mod tests {
         14 | foo([x=]val.y()[1])
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        from typing import List
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+            def x() -> List[int]:
+                return 1
+            def y() -> List[int]:
+                return 2
+        val: MyClass = MyClass()
+
+        foo(val.x()[0])
+        foo(val.y()[1])
         ");
     }
 
@@ -4193,6 +4431,17 @@ mod tests {
         7 | foo([x=]y[0])
           |      ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        x: list[Unknown | int] = [1]
+        y: list[Unknown | int] = [2]
+
+        foo(x[0])
+        foo(y[0])
         "#);
     }
 
@@ -4378,6 +4627,15 @@ mod tests {
         5 | f[: Foo] = Foo([x=]1)
           |                 ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class Foo:
+            def __init__(self, x: int): pass
+        Foo(1)
+        f: Foo = Foo(1)
         ");
     }
 
@@ -4450,6 +4708,15 @@ mod tests {
         5 | f[: Foo] = Foo([x=]1)
           |                 ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class Foo:
+            def __new__(cls, x: int): pass
+        Foo(1)
+        f: Foo = Foo(1)
         ");
     }
 
@@ -5197,6 +5464,15 @@ mod tests {
           |         ^^^^^^^^^^^^^
         5 | my_func(x="hello")
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        from typing import LiteralString
+        def my_func(x: LiteralString):
+            y: LiteralString = x
+        my_func(x="hello")
         "#);
     }
 
@@ -5339,6 +5615,23 @@ mod tests {
         13 |     y[: Literal[1, 2, 3, "hello"] | None] = x
            |                                     ^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def branch(cond: int):
+            if cond < 10:
+                x = 1
+            elif cond < 20:
+                x = 2
+            elif cond < 30:
+                x = 3
+            elif cond < 40:
+                x = "hello"
+            else:
+                x = None
+            y: Literal[1, 2, 3, "hello"] | None = x
         "#);
     }
 
@@ -5454,6 +5747,13 @@ mod tests {
         3 |     y[: type[list[str]]] = type(x)
           |                   ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def f(x: list[str]):
+            y: type[list[str]] = type(x)
         "#);
     }
 
@@ -5493,6 +5793,16 @@ mod tests {
         6 | ab[: property] = F.whatever
           |      ^^^^^^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class F:
+            @property
+            def whatever(self): ...
+
+        ab: property = F.whatever
         ");
     }
 
@@ -5810,6 +6120,180 @@ mod tests {
         ");
     }
 
+    #[test]
+    fn test_function_signature_inlay_hint() {
+        let mut test = inlay_hint_test(
+            "
+                  def foo(x: int, *y: bool, z: str | int | list[str]): ...
+
+                  a = foo",
+        );
+
+        assert_snapshot!(test.inlay_hints(), @r#"
+        def foo(x: int, *y: bool, z: str | int | list[str]): ...
+
+        a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+        ---------------------------------------------
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> main2.py:4:16
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+            --> stdlib/builtins.pyi:2591:7
+             |
+        2590 | @final
+        2591 | class bool(int):
+             |       ^^^^
+        2592 |     """Returns True when the argument is true, False otherwise.
+        2593 |     The builtins True and False are the only two instances of the class bool.
+             |
+        info: Source
+         --> main2.py:4:25
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                         ^^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+         --> main2.py:4:37
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                     ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> main2.py:4:43
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                           ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+            --> stdlib/builtins.pyi:2802:7
+             |
+        2801 | @disjoint_base
+        2802 | class list(MutableSequence[_T]):
+             |       ^^^^
+        2803 |     """Built-in mutable sequence.
+             |
+        info: Source
+         --> main2.py:4:49
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                 ^^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+         --> main2.py:4:54
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                      ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+          --> stdlib/ty_extensions.pyi:20:1
+           |
+        19 | # Types
+        20 | Unknown = object()
+           | ^^^^^^^
+        21 | AlwaysTruthy = object()
+        22 | AlwaysFalsy = object()
+           |
+        info: Source
+         --> main2.py:4:63
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                               ^^^^^^^
+          |
+        "#);
+    }
+
+    #[test]
+    fn test_module_inlay_hint() {
+        let mut test = inlay_hint_test(
+            "
+                      import foo
+
+                      a = foo",
+        );
+
+        test.with_extra_file("foo.py", "'''Foo module'''");
+
+        assert_snapshot!(test.inlay_hints(), @r"
+        import foo
+
+        a[: <module 'foo'>] = foo
+        ---------------------------------------------
+        info[inlay-hint-location]: Inlay Hint Target
+         --> foo.py:1:1
+          |
+        1 | '''Foo module'''
+          | ^^^^^^^^^^^^^^^^
+          |
+        info: Source
+         --> main2.py:4:5
+          |
+        2 | import foo
+        3 |
+        4 | a[: <module 'foo'>] = foo
+          |     ^^^^^^^^^^^^^^
+          |
+        ");
+    }
+
     struct InlayHintLocationDiagnostic {
         source: FileRange,
         target: FileRange,
@@ -5847,4 +6331,31 @@ mod tests {
             main
         }
     }
+
+    struct InlayHintEditDiagnostic {
+        file_content: String,
+    }
+
+    impl InlayHintEditDiagnostic {
+        fn new(file_content: String) -> Self {
+            Self { file_content }
+        }
+    }
+
+    impl IntoDiagnostic for InlayHintEditDiagnostic {
+        fn into_diagnostic(self) -> Diagnostic {
+            let mut main = Diagnostic::new(
+                DiagnosticId::Lint(LintName::of("inlay-hint-edit")),
+                Severity::Info,
+                "File after edits".to_string(),
+            );
+
+            main.sub(SubDiagnostic::new(
+                SubDiagnosticSeverity::Info,
+                format!("{}\n{}", "Source", self.file_content),
+            ));
+
+            main
+        }
+    }
 }

crates/ty_ide/src/lib.rs

@@ -33,7 +33,9 @@ pub use document_symbols::document_symbols;
 pub use goto::{goto_declaration, goto_definition, goto_type_definition};
 pub use goto_references::goto_references;
 pub use hover::hover;
-pub use inlay_hints::{InlayHintKind, InlayHintLabel, InlayHintSettings, inlay_hints};
+pub use inlay_hints::{
+    InlayHintKind, InlayHintLabel, InlayHintSettings, InlayHintTextEdit, inlay_hints,
+};
 pub use markup::MarkupKind;
 pub use references::ReferencesMode;
 pub use rename::{can_rename, rename};

crates/ty_python_semantic/resources/mdtest/async.md

@@ -79,9 +79,8 @@ async def main():
         task("B"),
     )
 
-    # TODO: these should be `int`
-    reveal_type(a)  # revealed: Unknown
-    reveal_type(b)  # revealed: Unknown
+    reveal_type(a)  # revealed: int
+    reveal_type(b)  # revealed: int
 ```
 
 ## Under the hood

crates/ty_python_semantic/resources/mdtest/call/callables_as_descriptors.md

@@ -237,4 +237,26 @@ class Matrix:
 Matrix() < Matrix()
 ```
 
+## `self`-binding behaviour of function-like `Callable`s
+
+Binding the `self` parameter of a function-like `Callable` creates a new `Callable` that is also
+function-like:
+
+`main.py`:
+
+```py
+from typing import Callable
+
+def my_lossy_decorator(fn: Callable[..., int]) -> Callable[..., int]:
+    return fn
+
+class MyClass:
+    @my_lossy_decorator
+    def method(self) -> int:
+        return 42
+
+reveal_type(MyClass().method)  # revealed: (...) -> int
+reveal_type(MyClass().method.__name__)  # revealed: str
+```
+
 [`tensorbase`]: https://github.com/pytorch/pytorch/blob/f3913ea641d871f04fa2b6588a77f63efeeb9f10/torch/_tensor.py#L1084-L1092

crates/ty_python_semantic/resources/mdtest/diagnostics/same_names.md

@@ -171,7 +171,7 @@ class Config:
 import generic_a
 import generic_b
 
-# TODO should be error: [invalid-assignment] "Object of type `<class 'generic_b.Container[int]'>` is not assignable to `type[generic_a.Container[int]]`"
+# error: [invalid-assignment] "Object of type `<class 'generic_b.Container[int]'>` is not assignable to `type[generic_a.Container[int]]`"
 container: type[generic_a.Container[int]] = generic_b.Container[int]
 ```
 

crates/ty_python_semantic/resources/mdtest/generics/specialize_constrained.md

@@ -22,8 +22,10 @@ from ty_extensions import ConstraintSet, generic_context
 # fmt: off
 
 def unbounded[T]():
-    # revealed: ty_extensions.Specialization[T@unbounded = object]
+    # revealed: ty_extensions.Specialization[T@unbounded = Unknown]
     reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.always()))
+    # revealed: ty_extensions.Specialization[T@unbounded = object]
+    reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.range(Never, T, object)))
     # revealed: None
     reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.never()))
 
@@ -88,6 +90,7 @@ that makes the test succeed.
 from typing import Any
 
 def bounded_by_gradual[T: Any]():
+    # TODO: revealed: ty_extensions.Specialization[T@bounded_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@bounded_by_gradual = object]
     reveal_type(generic_context(bounded_by_gradual).specialize_constrained(ConstraintSet.always()))
     # revealed: None
@@ -168,12 +171,16 @@ from typing import Any
 # fmt: off
 
 def constrained_by_gradual[T: (Base, Any)]():
+    # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Unknown]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
+    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.always()))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = object]
-    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.always()))
+    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, object)))
     # revealed: None
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.never()))
 
+    # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Base)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
@@ -181,14 +188,14 @@ def constrained_by_gradual[T: (Base, Any)]():
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Unrelated)))
 
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
-    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Super]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Super)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Super]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Super, T, Super)))
 
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
-    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = object]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Sub, T, object)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Sub]
@@ -288,7 +295,7 @@ class Unrelated: ...
 # fmt: off
 
 def mutually_bound[T: Base, U]():
-    # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = object]
+    # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = Unknown]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.always()))
     # revealed: None
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.never()))
@@ -296,7 +303,7 @@ def mutually_bound[T: Base, U]():
     # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = Base]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, U, T)))
 
-    # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = object]
+    # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = Unknown]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, T, Sub)))
     # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = Sub]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, T, Sub) & ConstraintSet.range(Never, U, T)))

crates/ty_python_semantic/resources/mdtest/implicit_type_aliases.md

@@ -191,13 +191,13 @@ def _(
     reveal_type(int_or_callable)  # revealed: int | ((str, /) -> bytes)
     reveal_type(callable_or_int)  # revealed: ((str, /) -> bytes) | int
     # TODO should be Unknown | int
-    reveal_type(type_var_or_int)  # revealed: typing.TypeVar | int
+    reveal_type(type_var_or_int)  # revealed: T@TypeVarOrInt | int
     # TODO should be int | Unknown
-    reveal_type(int_or_type_var)  # revealed: int | typing.TypeVar
+    reveal_type(int_or_type_var)  # revealed: int | T@IntOrTypeVar
     # TODO should be Unknown | None
-    reveal_type(type_var_or_none)  # revealed: typing.TypeVar | None
+    reveal_type(type_var_or_none)  # revealed: T@TypeVarOrNone | None
     # TODO should be None | Unknown
-    reveal_type(none_or_type_var)  # revealed: None | typing.TypeVar
+    reveal_type(none_or_type_var)  # revealed: None | T@NoneOrTypeVar
 ```
 
 If a type is unioned with itself in a value expression, the result is just that type. No
@@ -366,7 +366,9 @@ def g(obj: Y):
     reveal_type(obj)  # revealed: list[int | str]
 ```
 
-## Generic types
+## Generic implicit type aliases
+
+### Functionality
 
 Implicit type aliases can also be generic:
 
@@ -388,24 +390,25 @@ ListOrTuple = list[T] | tuple[T, ...]
 ListOrTupleLegacy = Union[list[T], tuple[T, ...]]
 MyCallable = Callable[P, T]
 AnnotatedType = Annotated[T, "tag"]
+TransparentAlias = T
+MyOptional = T | None
 
-# TODO: Consider displaying this as `<class 'list[T]'>`, … instead? (and similar for some others below)
-reveal_type(MyList)  # revealed: <class 'list[typing.TypeVar]'>
-reveal_type(MyDict)  # revealed: <class 'dict[typing.TypeVar, typing.TypeVar]'>
+reveal_type(MyList)  # revealed: <class 'list[T@MyList]'>
+reveal_type(MyDict)  # revealed: <class 'dict[T@MyDict, U@MyDict]'>
 reveal_type(MyType)  # revealed: GenericAlias
-reveal_type(IntAndType)  # revealed: <class 'tuple[int, typing.TypeVar]'>
-reveal_type(Pair)  # revealed: <class 'tuple[typing.TypeVar, typing.TypeVar]'>
-reveal_type(Sum)  # revealed: <class 'tuple[typing.TypeVar, typing.TypeVar]'>
+reveal_type(IntAndType)  # revealed: <class 'tuple[int, T@IntAndType]'>
+reveal_type(Pair)  # revealed: <class 'tuple[T@Pair, T@Pair]'>
+reveal_type(Sum)  # revealed: <class 'tuple[T@Sum, U@Sum]'>
 reveal_type(ListOrTuple)  # revealed: types.UnionType
 reveal_type(ListOrTupleLegacy)  # revealed: types.UnionType
 reveal_type(MyCallable)  # revealed: GenericAlias
 reveal_type(AnnotatedType)  # revealed: <typing.Annotated special form>
+reveal_type(TransparentAlias)  # revealed: typing.TypeVar
+reveal_type(MyOptional)  # revealed: types.UnionType
 
 def _(
     list_of_ints: MyList[int],
     dict_str_to_int: MyDict[str, int],
-    # TODO: no error here
-    # error: [invalid-type-form] "`typing.TypeVar` is not a generic class"
     subclass_of_int: MyType[int],
     int_and_str: IntAndType[str],
     pair_of_ints: Pair[int],
@@ -413,48 +416,40 @@ def _(
     list_or_tuple: ListOrTuple[int],
     list_or_tuple_legacy: ListOrTupleLegacy[int],
     # TODO: no error here
+    # error: [too-many-positional-arguments] "Too many positional arguments: expected 1, got 2"
     # error: [invalid-type-form] "List literals are not allowed in this context in a type expression: Did you mean `tuple[str, bytes]`?"
     my_callable: MyCallable[[str, bytes], int],
     annotated_int: AnnotatedType[int],
+    transparent_alias: TransparentAlias[int],
+    optional_int: MyOptional[int],
 ):
-    # TODO: This should be `list[int]`
-    reveal_type(list_of_ints)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: This should be `dict[str, int]`
-    reveal_type(dict_str_to_int)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: This should be `type[int]`
-    reveal_type(subclass_of_int)  # revealed: Unknown
-    # TODO: This should be `tuple[int, str]`
-    reveal_type(int_and_str)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: This should be `tuple[int, int]`
-    reveal_type(pair_of_ints)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: This should be `tuple[int, bytes]`
-    reveal_type(int_and_bytes)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: This should be `list[int] | tuple[int, ...]`
-    reveal_type(list_or_tuple)  # revealed: @Todo(Generic specialization of types.UnionType)
-    # TODO: This should be `list[int] | tuple[int, ...]`
-    reveal_type(list_or_tuple_legacy)  # revealed: @Todo(Generic specialization of types.UnionType)
+    reveal_type(list_of_ints)  # revealed: list[int]
+    reveal_type(dict_str_to_int)  # revealed: dict[str, int]
+    reveal_type(subclass_of_int)  # revealed: type[int]
+    reveal_type(int_and_str)  # revealed: tuple[int, str]
+    reveal_type(pair_of_ints)  # revealed: tuple[int, int]
+    reveal_type(int_and_bytes)  # revealed: tuple[int, bytes]
+    reveal_type(list_or_tuple)  # revealed: list[int] | tuple[int, ...]
+    reveal_type(list_or_tuple_legacy)  # revealed: list[int] | tuple[int, ...]
+    reveal_type(list_or_tuple_legacy)  # revealed: list[int] | tuple[int, ...]
     # TODO: This should be `(str, bytes) -> int`
-    reveal_type(my_callable)  # revealed: @Todo(Generic specialization of typing.Callable)
-    # TODO: This should be `int`
-    reveal_type(annotated_int)  # revealed: @Todo(Generic specialization of typing.Annotated)
+    reveal_type(my_callable)  # revealed: Unknown
+    reveal_type(annotated_int)  # revealed: int
+    reveal_type(transparent_alias)  # revealed: int
+    reveal_type(optional_int)  # revealed: int | None
 ```
 
 Generic implicit type aliases can be partially specialized:
 
 ```py
-U = TypeVar("U")
-
 DictStrTo = MyDict[str, U]
 
-reveal_type(DictStrTo)  # revealed: GenericAlias
+reveal_type(DictStrTo)  # revealed: <class 'dict[str, U@DictStrTo]'>
 
 def _(
-    # TODO: No error here
-    # error: [invalid-type-form] "Invalid subscript of object of type `GenericAlias` in type expression"
     dict_str_to_int: DictStrTo[int],
 ):
-    # TODO: This should be `dict[str, int]`
-    reveal_type(dict_str_to_int)  # revealed: Unknown
+    reveal_type(dict_str_to_int)  # revealed: dict[str, int]
 ```
 
 Using specializations of generic implicit type aliases in other implicit type aliases works as
@@ -464,26 +459,65 @@ expected:
 IntsOrNone = MyList[int] | None
 IntsOrStrs = Pair[int] | Pair[str]
 ListOfPairs = MyList[Pair[str]]
+ListOrTupleOfInts = ListOrTuple[int]
+AnnotatedInt = AnnotatedType[int]
+SubclassOfInt = MyType[int]
+# TODO: No error here
+# error: [too-many-positional-arguments] "Too many positional arguments: expected 1, got 2"
+# error: [invalid-type-form] "List literals are not allowed in this context in a type expression: Did you mean `list[int]`?"
+CallableIntToStr = MyCallable[[int], str]
 
-reveal_type(IntsOrNone)  # revealed: UnionType
-reveal_type(IntsOrStrs)  # revealed: UnionType
-reveal_type(ListOfPairs)  # revealed: GenericAlias
+reveal_type(IntsOrNone)  # revealed: types.UnionType
+reveal_type(IntsOrStrs)  # revealed: types.UnionType
+reveal_type(ListOfPairs)  # revealed: <class 'list[tuple[str, str]]'>
+reveal_type(ListOrTupleOfInts)  # revealed: types.UnionType
+reveal_type(AnnotatedInt)  # revealed: <typing.Annotated special form>
+reveal_type(SubclassOfInt)  # revealed: GenericAlias
+reveal_type(CallableIntToStr)  # revealed: Unknown
 
 def _(
-    # TODO: This should not be an error
-    # error: [invalid-type-form] "Variable of type `UnionType` is not allowed in a type expression"
     ints_or_none: IntsOrNone,
-    # TODO: This should not be an error
-    # error: [invalid-type-form] "Variable of type `UnionType` is not allowed in a type expression"
     ints_or_strs: IntsOrStrs,
     list_of_pairs: ListOfPairs,
+    list_or_tuple_of_ints: ListOrTupleOfInts,
+    annotated_int: AnnotatedInt,
+    subclass_of_int: SubclassOfInt,
+    callable_int_to_str: CallableIntToStr,
 ):
-    # TODO: This should be `list[int] | None`
-    reveal_type(ints_or_none)  # revealed: Unknown
-    # TODO: This should be `tuple[int, int] | tuple[str, str]`
-    reveal_type(ints_or_strs)  # revealed: Unknown
-    # TODO: This should be `list[tuple[str, str]]`
-    reveal_type(list_of_pairs)  # revealed: @Todo(Support for `typing.GenericAlias` instances in type expressions)
+    reveal_type(ints_or_none)  # revealed: list[int] | None
+    reveal_type(ints_or_strs)  # revealed: tuple[int, int] | tuple[str, str]
+    reveal_type(list_of_pairs)  # revealed: list[tuple[str, str]]
+    reveal_type(list_or_tuple_of_ints)  # revealed: list[int] | tuple[int, ...]
+    reveal_type(annotated_int)  # revealed: int
+    reveal_type(subclass_of_int)  # revealed: type[int]
+    # TODO: This should be `(int, /) -> str`
+    reveal_type(callable_int_to_str)  # revealed: Unknown
+```
+
+A generic implicit type alias can also be used in another generic implicit type alias:
+
+```py
+from typing_extensions import Any
+
+B = TypeVar("B", bound=int)
+
+MyOtherList = MyList[T]
+MyOtherType = MyType[T]
+TypeOrList = MyType[B] | MyList[B]
+
+reveal_type(MyOtherList)  # revealed: <class 'list[T@MyOtherList]'>
+reveal_type(MyOtherType)  # revealed: GenericAlias
+reveal_type(TypeOrList)  # revealed: types.UnionType
+
+def _(
+    list_of_ints: MyOtherList[int],
+    subclass_of_int: MyOtherType[int],
+    type_or_list: TypeOrList[Any],
+):
+    reveal_type(list_of_ints)  # revealed: list[int]
+    reveal_type(subclass_of_int)  # revealed: type[int]
+    # TODO: Should be `type[Any] | list[Any]`
+    reveal_type(type_or_list)  # revealed: @Todo(type[T] for typevar T) | list[Any]
 ```
 
 If a generic implicit type alias is used unspecialized in a type expression, we treat it as an
@@ -496,11 +530,11 @@ def _(
     my_callable: MyCallable,
 ):
     # TODO: Should be `list[Unknown]`
-    reveal_type(my_list)  # revealed: list[typing.TypeVar]
+    reveal_type(my_list)  # revealed: list[T@MyList]
     # TODO: Should be `dict[Unknown, Unknown]`
-    reveal_type(my_dict)  # revealed: dict[typing.TypeVar, typing.TypeVar]
+    reveal_type(my_dict)  # revealed: dict[T@MyDict, U@MyDict]
     # TODO: Should be `(...) -> Unknown`
-    reveal_type(my_callable)  # revealed: (...) -> typing.TypeVar
+    reveal_type(my_callable)  # revealed: (...) -> T@MyCallable
 ```
 
 (Generic) implicit type aliases can be used as base classes:
@@ -522,37 +556,182 @@ reveal_mro(Derived1)
 
 GenericBaseAlias = GenericBase[T]
 
-# TODO: No error here
-# error: [non-subscriptable] "Cannot subscript object of type `<class 'GenericBase[typing.TypeVar]'>` with no `__class_getitem__` method"
 class Derived2(GenericBaseAlias[int]):
     pass
 ```
 
+### Imported aliases
+
+Generic implicit type aliases can be imported from other modules and specialized:
+
+`my_types.py`:
+
+```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+MyList = list[T]
+```
+
+`main.py`:
+
+```py
+from my_types import MyList
+import my_types as mt
+
+def _(
+    list_of_ints1: MyList[int],
+    list_of_ints2: mt.MyList[int],
+):
+    reveal_type(list_of_ints1)  # revealed: list[int]
+    reveal_type(list_of_ints2)  # revealed: list[int]
+```
+
+### In stringified annotations
+
+Generic implicit type aliases can be specialized in stringified annotations:
+
+```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+MyList = list[T]
+
+def _(
+    list_of_ints: "MyList[int]",
+):
+    reveal_type(list_of_ints)  # revealed: list[int]
+```
+
+### Error cases
+
 A generic alias that is already fully specialized cannot be specialized again:
 
 ```py
 ListOfInts = list[int]
 
-# TODO: this should be an error
+# error: [too-many-positional-arguments] "Too many positional arguments: expected 0, got 1"
 def _(doubly_specialized: ListOfInts[int]):
-    # TODO: this should be `Unknown`
-    reveal_type(doubly_specialized)  # revealed: @Todo(specialized generic alias in type expression)
+    reveal_type(doubly_specialized)  # revealed: Unknown
 ```
 
 Specializing a generic implicit type alias with an incorrect number of type arguments also results
 in an error:
 
 ```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+U = TypeVar("U")
+
+MyList = list[T]
+MyDict = dict[T, U]
+
 def _(
-    # TODO: this should be an error
+    # error: [too-many-positional-arguments] "Too many positional arguments: expected 1, got 2"
     list_too_many_args: MyList[int, str],
-    # TODO: this should be an error
+    # error: [missing-argument] "No argument provided for required parameter `U`"
     dict_too_few_args: MyDict[int],
 ):
-    # TODO: this should be `Unknown`
-    reveal_type(list_too_many_args)  # revealed: @Todo(specialized generic alias in type expression)
-    # TODO: this should be `Unknown`
-    reveal_type(dict_too_few_args)  # revealed: @Todo(specialized generic alias in type expression)
+    reveal_type(list_too_many_args)  # revealed: Unknown
+    reveal_type(dict_too_few_args)  # revealed: Unknown
+```
+
+Trying to specialize a non-name node results in an error:
+
+```py
+from ty_extensions import TypeOf
+
+IntOrStr = int | str
+
+def this_does_not_work() -> TypeOf[IntOrStr]:
+    raise NotImplementedError()
+
+def _(
+    # TODO: Better error message? `invalid-type-form`
+    # error: [too-many-positional-arguments] "Too many positional arguments: expected 0, got 1"
+    specialized: this_does_not_work()[int],
+):
+    reveal_type(specialized)  # revealed: Unknown
+```
+
+Similarly, if you try to specialize a union type without a binding context, we emit an error:
+
+```py
+# error: [invalid-type-form] "`types.UnionType` is not subscriptable"
+x: (list[T] | set[T])[int]
+
+def _():
+    reveal_type(x)  # revealed: Unknown
+```
+
+### Multiple definitions
+
+#### Shadowed definitions
+
+When a generic type alias shadows a definition from an outer scope, the inner definition is used:
+
+```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+MyAlias = list[T]
+
+def outer():
+    MyAlias = set[T]
+
+    def _(x: MyAlias[int]):
+        reveal_type(x)  # revealed: set[int]
+```
+
+#### Statically known conditions
+
+```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+if True:
+    MyAlias1 = list[T]
+else:
+    MyAlias1 = set[T]
+
+if False:
+    MyAlias2 = list[T]
+else:
+    MyAlias2 = set[T]
+
+def _(
+    x1: MyAlias1[int],
+    x2: MyAlias2[int],
+):
+    reveal_type(x1)  # revealed: list[int]
+    reveal_type(x2)  # revealed: set[int]
+```
+
+#### Statically unknown conditions
+
+If several definitions are visible, we emit an error:
+
+```py
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+def flag() -> bool:
+    return True
+
+if flag():
+    MyAlias = list[T]
+else:
+    MyAlias = set[T]
+
+# error: [invalid-type-form] "Invalid subscript of object of type `<class 'list[T@MyAlias]'> | <class 'set[T@MyAlias]'>` in type expression"
+def _(x: MyAlias[int]):
+    reveal_type(x)  # revealed: Unknown
 ```
 
 ## `Literal`s
@@ -642,8 +821,7 @@ Deprecated = Annotated[T, "deprecated attribute"]
 class C:
     old: Deprecated[int]
 
-# TODO: Should be `int`
-reveal_type(C().old)  # revealed: @Todo(Generic specialization of typing.Annotated)
+reveal_type(C().old)  # revealed: int
 ```
 
 If the metadata argument is missing, we emit an error (because this code fails at runtime), but
@@ -1298,3 +1476,14 @@ def _(
     reveal_type(recursive_dict3)  # revealed: dict[Divergent, int]
     reveal_type(recursive_dict4)  # revealed: dict[Divergent, int]
 ```
+
+### Self-referential generic implicit type aliases
+
+<!-- expect-panic: execute: too many cycle iterations -->
+
+```py
+from typing import TypeVar
+
+T = TypeVar("T")
+NestedDict = dict[str, "NestedDict[T] | T"]
+```

crates/ty_python_semantic/resources/mdtest/liskov.md

@@ -523,3 +523,63 @@ class Baz(NamedTuple):
 class Spam(Baz):
     def _asdict(self) -> tuple[int, ...]: ...  # error: [invalid-method-override]
 ```
+
+## Staticmethods and classmethods
+
+Methods decorated with `@staticmethod` or `@classmethod` are checked in much the same way as other
+methods.
+
+<!-- snapshot-diagnostics -->
+
+```pyi
+class Parent:
+    def instance_method(self, x: int) -> int: ...
+    @classmethod
+    def class_method(cls, x: int) -> int: ...
+    @staticmethod
+    def static_method(x: int) -> int: ...
+
+class BadChild1(Parent):
+    @staticmethod
+    def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+    # TODO: we should emit `invalid-method-override` here.
+    # Although the method has the same signature as `Parent.class_method`
+    # when accessed on instances, it does not have the same signature as
+    # `Parent.class_method` when accessed on the class object itself
+    def class_method(cls, x: int) -> int: ...
+    def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+
+class BadChild2(Parent):
+    # TODO: we should emit `invalid-method-override` here.
+    # Although the method has the same signature as `Parent.class_method`
+    # when accessed on instances, it does not have the same signature as
+    # `Parent.class_method` when accessed on the class object itself.
+    #
+    # Note that whereas `BadChild1.class_method` is reported as a Liskov violation by
+    # mypy, pyright and pyrefly, pyright is the only one of those three to report a
+    # Liskov violation on this method as of 2025-11-23.
+    @classmethod
+    def instance_method(self, x: int) -> int: ...
+    @staticmethod
+    def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+    @classmethod
+    def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+
+class BadChild3(Parent):
+    @classmethod
+    def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+    @staticmethod
+    def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+
+class GoodChild1(Parent):
+    @classmethod
+    def class_method(cls, x: int) -> int: ...
+    @staticmethod
+    def static_method(x: int) -> int: ...
+
+class GoodChild2(Parent):
+    @classmethod
+    def class_method(cls, x: object) -> bool: ...
+    @staticmethod
+    def static_method(x: object) -> bool: ...
+```

crates/ty_python_semantic/resources/mdtest/pep613_type_aliases.md

@@ -96,6 +96,24 @@ def _(x: MyAlias):
     reveal_type(x)  # revealed: int | ((str, /) -> int)
 ```
 
+## Generic aliases
+
+```py
+from typing import TypeAlias, TypeVar
+
+T = TypeVar("T")
+
+MyList: TypeAlias = list[T]
+ListOrSet: TypeAlias = list[T] | set[T]
+
+reveal_type(MyList)  # revealed: <class 'list[T]'>
+reveal_type(ListOrSet)  # revealed: types.UnionType
+
+def _(list_of_int: MyList[int], list_or_set_of_str: ListOrSet[str]):
+    reveal_type(list_of_int)  # revealed: list[int]
+    reveal_type(list_or_set_of_str)  # revealed: list[str] | set[str]
+```
+
 ## Subscripted generic alias in union
 
 ```py
@@ -107,8 +125,7 @@ Alias1: TypeAlias = list[T] | set[T]
 MyAlias: TypeAlias = int | Alias1[str]
 
 def _(x: MyAlias):
-    # TODO: int | list[str] | set[str]
-    reveal_type(x)  # revealed: int | @Todo(Specialization of union type alias)
+    reveal_type(x)  # revealed: int | list[str] | set[str]
 ```
 
 ## Imported

crates/ty_python_semantic/resources/mdtest/snapshots/liskov.md_-_The_Liskov_Substitut…_-_Staticmethods_and_cl…_(49e28aae6fdd1291).snap

@@ -0,0 +1,220 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: liskov.md - The Liskov Substitution Principle - Staticmethods and classmethods
+mdtest path: crates/ty_python_semantic/resources/mdtest/liskov.md
+---
+
+# Python source files
+
+## mdtest_snippet.pyi
+
+```
+ 1 | class Parent:
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+ 7 | 
+ 8 | class BadChild1(Parent):
+ 9 |     @staticmethod
+10 |     def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+11 |     # TODO: we should emit `invalid-method-override` here.
+12 |     # Although the method has the same signature as `Parent.class_method`
+13 |     # when accessed on instances, it does not have the same signature as
+14 |     # `Parent.class_method` when accessed on the class object itself
+15 |     def class_method(cls, x: int) -> int: ...
+16 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+17 | 
+18 | class BadChild2(Parent):
+19 |     # TODO: we should emit `invalid-method-override` here.
+20 |     # Although the method has the same signature as `Parent.class_method`
+21 |     # when accessed on instances, it does not have the same signature as
+22 |     # `Parent.class_method` when accessed on the class object itself.
+23 |     #
+24 |     # Note that whereas `BadChild1.class_method` is reported as a Liskov violation by
+25 |     # mypy, pyright and pyrefly, pyright is the only one of those three to report a
+26 |     # Liskov violation on this method as of 2025-11-23.
+27 |     @classmethod
+28 |     def instance_method(self, x: int) -> int: ...
+29 |     @staticmethod
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+33 | 
+34 | class BadChild3(Parent):
+35 |     @classmethod
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+39 | 
+40 | class GoodChild1(Parent):
+41 |     @classmethod
+42 |     def class_method(cls, x: int) -> int: ...
+43 |     @staticmethod
+44 |     def static_method(x: int) -> int: ...
+45 | 
+46 | class GoodChild2(Parent):
+47 |     @classmethod
+48 |     def class_method(cls, x: object) -> bool: ...
+49 |     @staticmethod
+50 |     def static_method(x: object) -> bool: ...
+```
+
+# Diagnostics
+
+```
+error[invalid-method-override]: Invalid override of method `instance_method`
+  --> src/mdtest_snippet.pyi:10:9
+   |
+ 8 | class BadChild1(Parent):
+ 9 |     @staticmethod
+10 |     def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.instance_method`
+11 |     # TODO: we should emit `invalid-method-override` here.
+12 |     # Although the method has the same signature as `Parent.class_method`
+   |
+  ::: src/mdtest_snippet.pyi:2:9
+   |
+ 1 | class Parent:
+ 2 |     def instance_method(self, x: int) -> int: ...
+   |         ------------------------------------ `Parent.instance_method` defined here
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |
+info: `BadChild1.instance_method` is a staticmethod but `Parent.instance_method` is an instance method
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:16:9
+   |
+14 |     # `Parent.class_method` when accessed on the class object itself
+15 |     def class_method(cls, x: int) -> int: ...
+16 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+17 |
+18 | class BadChild2(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: `BadChild1.static_method` is an instance method but `Parent.static_method` is a staticmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `class_method`
+  --> src/mdtest_snippet.pyi:30:9
+   |
+28 |     def instance_method(self, x: int) -> int: ...
+29 |     @staticmethod
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.class_method`
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |
+  ::: src/mdtest_snippet.pyi:4:9
+   |
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |         -------------------------------- `Parent.class_method` defined here
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |
+info: `BadChild2.class_method` is a staticmethod but `Parent.class_method` is a classmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:32:9
+   |
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+33 |
+34 | class BadChild3(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: `BadChild2.static_method` is a classmethod but `Parent.static_method` is a staticmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `class_method`
+  --> src/mdtest_snippet.pyi:36:9
+   |
+34 | class BadChild3(Parent):
+35 |     @classmethod
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.class_method`
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+   |
+  ::: src/mdtest_snippet.pyi:4:9
+   |
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |         -------------------------------- `Parent.class_method` defined here
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:38:9
+   |
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+39 |
+40 | class GoodChild1(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```

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

@@ -174,6 +174,39 @@ def _(x: Foo[int], y: Bar[str], z: list[bytes]):
     reveal_type(type(z))  # revealed: type[list[bytes]]
 ```
 
+## Checking generic `type[]` types
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+class C[T]:
+    pass
+
+class D[T]:
+    pass
+
+var: type[C[int]] = C[int]
+var: type[C[int]] = D[int]  # error: [invalid-assignment] "Object of type `<class 'D[int]'>` is not assignable to `type[C[int]]`"
+```
+
+However, generic `Protocol` classes are still TODO:
+
+```py
+from typing import Protocol
+
+class Proto[U](Protocol):
+    def some_method(self): ...
+
+# TODO: should be error: [invalid-assignment]
+var: type[Proto[int]] = C[int]
+
+def _(p: type[Proto[int]]):
+    reveal_type(p)  # revealed: type[@Todo(type[T] for protocols)]
+```
+
 ## `@final` classes
 
 `type[]` types are eagerly converted to class-literal types if a class decorated with `@final` is

crates/ty_python_semantic/resources/mdtest/type_properties/constraints.md

@@ -66,12 +66,15 @@ def _[T]() -> None:
     reveal_type(ConstraintSet.range(Base, T, object))
 ```
 
-And a range constraint with _both_ a lower bound of `Never` and an upper bound of `object` does not
-constrain the typevar at all.
+And a range constraint with a lower bound of `Never` and an upper bound of `object` allows the
+typevar to take on any type. We treat this differently than the `always` constraint set. During
+specialization inference, that allows us to distinguish between not constraining a typevar (and
+therefore falling back on its default specialization) and explicitly constraining it to any subtype
+of `object`.
 
 ```py
 def _[T]() -> None:
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@_ = *)]
     reveal_type(ConstraintSet.range(Never, T, object))
 ```
 
@@ -156,7 +159,7 @@ cannot be satisfied at all.
 
 ```py
 def _[T]() -> None:
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@_ ≠ *)]
     reveal_type(~ConstraintSet.range(Never, T, object))
 ```
 
@@ -654,7 +657,7 @@ def _[T]() -> None:
     reveal_type(~ConstraintSet.range(Never, T, Base))
     # revealed: ty_extensions.ConstraintSet[¬(Sub ≤ T@_)]
     reveal_type(~ConstraintSet.range(Sub, T, object))
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@_ ≠ *)]
     reveal_type(~ConstraintSet.range(Never, T, object))
 ```
 
@@ -811,7 +814,7 @@ def f[T]():
     # "domain", which maps valid inputs to `true` and invalid inputs to `false`. This means that two
     # constraint sets that are both always satisfied will not be identical if they have different
     # domains!
-    always = ConstraintSet.range(Never, T, object)
+    always = ConstraintSet.always()
     # revealed: ty_extensions.ConstraintSet[always]
     reveal_type(always)
     static_assert(always)
@@ -846,11 +849,11 @@ from typing import Never
 from ty_extensions import ConstraintSet
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Never, T, T))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(T, T, object))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(T, T, T))
 ```
 
@@ -862,11 +865,11 @@ as shown above.)
 from ty_extensions import Intersection
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Never, T, T | None))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Intersection[T, None], T, object))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Intersection[T, None], T, T | None))
 ```
 
@@ -877,8 +880,8 @@ constraint set can never be satisfied, since every type is disjoint with its neg
 from ty_extensions import Not
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar ≠ *)]
     reveal_type(ConstraintSet.range(Intersection[Not[T], None], T, object))
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar ≠ *)]
     reveal_type(ConstraintSet.range(Not[T], T, object))
 ```

crates/ty_python_semantic/resources/mdtest/type_properties/is_assignable_to.md

@@ -243,13 +243,13 @@ static_assert(is_assignable_to(TypeOf[Bar[int]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar[bool]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[int]]))
+static_assert(is_assignable_to(TypeOf[Bar[Unknown]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar], type[Foo]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[Any]]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[int]]))
 
-# TODO: these should pass (all subscripts inside `type[]` type expressions are currently TODO types)
-static_assert(not is_assignable_to(TypeOf[Bar[int]], type[Foo[bool]]))  # error: [static-assert-error]
-static_assert(not is_assignable_to(TypeOf[Foo[bool]], type[Bar[int]]))  # error: [static-assert-error]
+static_assert(not is_assignable_to(TypeOf[Bar[int]], type[Foo[bool]]))
+static_assert(not is_assignable_to(TypeOf[Foo[bool]], type[Bar[int]]))
 ```
 
 ## `type[]` is not assignable to types disjoint from `builtins.type`

crates/ty_python_semantic/src/semantic_index/definition.rs

@@ -90,6 +90,12 @@ impl<'db> Definition<'db> {
                         .to_string(),
                 )
             }
+            DefinitionKind::Assignment(assignment) => {
+                let target_node = assignment.target.node(&module);
+                target_node
+                    .as_name_expr()
+                    .map(|name_expr| name_expr.id.as_str().to_string())
+            }
             _ => None,
         }
     }

crates/ty_python_semantic/src/types.rs

@@ -906,6 +906,13 @@ impl<'db> Type<'db> {
         matches!(self, Type::GenericAlias(_))
     }
 
+    // pub(crate) fn as_generic_alias(&self) -> Option<GenericAlias<'db>> {
+    //     match self {
+    //         Type::GenericAlias(alias) => Some(*alias),
+    //         _ => None,
+    //     }
+    // }
+
     const fn is_dynamic(&self) -> bool {
         matches!(self, Type::Dynamic(_))
     }
@@ -1107,13 +1114,6 @@ impl<'db> Type<'db> {
         }
     }
 
-    pub(crate) const fn as_bound_method(self) -> Option<BoundMethodType<'db>> {
-        match self {
-            Type::BoundMethod(bound_method) => Some(bound_method),
-            _ => None,
-        }
-    }
-
     #[track_caller]
     pub(crate) const fn expect_class_literal(self) -> ClassLiteral<'db> {
         self.as_class_literal()
@@ -1566,7 +1566,7 @@ impl<'db> Type<'db> {
                 }
             }
             Type::ClassLiteral(class_literal) => {
-                Some(ClassType::NonGeneric(class_literal).into_callable(db))
+                Some(class_literal.default_specialization(db).into_callable(db))
             }
 
             Type::GenericAlias(alias) => Some(ClassType::Generic(alias).into_callable(db)),
@@ -2406,7 +2406,7 @@ impl<'db> Type<'db> {
                 .subclass_of()
                 .into_class()
                 .map(|subclass_of_class| {
-                    ClassType::NonGeneric(class).has_relation_to_impl(
+                    class.default_specialization(db).has_relation_to_impl(
                         db,
                         subclass_of_class,
                         inferable,
@@ -6707,7 +6707,9 @@ impl<'db> Type<'db> {
                             KnownClass::Float.to_instance(db),
                         ],
                     ),
-                    _ if class.is_typed_dict(db) => Type::typed_dict(*class),
+                    _ if class.is_typed_dict(db) => {
+                        Type::typed_dict(class.default_specialization(db))
+                    }
                     _ => Type::instance(db, class.default_specialization(db)),
                 };
                 Ok(ty)
@@ -6797,7 +6799,7 @@ impl<'db> Type<'db> {
                 }
                 KnownInstanceType::Literal(ty) => Ok(ty.inner(db)),
                 KnownInstanceType::Annotated(ty) => Ok(ty.inner(db)),
-                KnownInstanceType::TypeGenericAlias(ty) => {
+                KnownInstanceType::TypeGenericAlias(instance) => {
                     // When `type[…]` appears in a value position (e.g. in an implicit type alias),
                     // we infer its argument as a type expression. This ensures that we can emit
                     // diagnostics for invalid type expressions, and more importantly, that we can
@@ -6806,9 +6808,26 @@ impl<'db> Type<'db> {
                     // (`int` -> instance of `int` -> subclass of `int`) can be lossy, but it is
                     // okay for all valid arguments to `type[…]`.
 
-                    Ok(ty.inner(db).to_meta_type(db))
+                    let ty = instance.inner(db);
+
+                    if ty.is_type_var() {
+                        // TODO:
+                        // This is a temporary workaround until we have proper support for type[T].
+                        // If we pass a typevar to `.to_meta_type()`, we currently get `type[B]`,
+                        // where `B` is the upper bound of `T`. However, we really need `type[T]`
+                        // here. Otherwise, when we specialize a generic implicit type alias like
+                        // `TypeOrList[T] = type[T] | list[T]` using `TypeOrList[Any]`, we would get
+                        // `type[B] | list[Any]`, which leads to a lot of false positives for numpy-
+                        // users.
+                        Ok(todo_type!("type[T] for typevar T"))
+                    } else {
+                        Ok(ty.to_meta_type(db))
+                    }
+                }
+                KnownInstanceType::GenericAlias(instance) => Ok(instance.inner(db)),
+                KnownInstanceType::Callable(instance) => {
+                    Ok(Type::Callable(instance.callable_type(db)))
                 }
-                KnownInstanceType::Callable(callable) => Ok(Type::Callable(*callable)),
                 KnownInstanceType::LiteralStringAlias(ty) => Ok(ty.inner(db)),
             },
 
@@ -7203,17 +7222,83 @@ impl<'db> Type<'db> {
                 }
             }
 
-            Type::KnownInstance(KnownInstanceType::TypeVar(typevar)) => match type_mapping {
-                TypeMapping::BindLegacyTypevars(binding_context) => {
-                    Type::TypeVar(BoundTypeVarInstance::new(db, typevar, *binding_context))
+            Type::KnownInstance(known_instance) => match known_instance {
+                KnownInstanceType::TypeVar(typevar) => {
+                    match type_mapping {
+                        TypeMapping::BindLegacyTypevars(binding_context) => {
+                            Type::TypeVar(BoundTypeVarInstance::new(db, typevar, *binding_context))
+                        }
+                        TypeMapping::Specialization(_) |
+                        TypeMapping::PartialSpecialization(_) |
+                        TypeMapping::PromoteLiterals(_) |
+                        TypeMapping::BindSelf(_) |
+                        TypeMapping::ReplaceSelf { .. } |
+                        TypeMapping::Materialize(_) |
+                        TypeMapping::ReplaceParameterDefaults => self,
+                    }
                 }
-                TypeMapping::Specialization(_) |
-                TypeMapping::PartialSpecialization(_) |
-                TypeMapping::PromoteLiterals(_) |
-                TypeMapping::BindSelf(_) |
-                TypeMapping::ReplaceSelf { .. } |
-                TypeMapping::Materialize(_) |
-                TypeMapping::ReplaceParameterDefaults => self,
+                KnownInstanceType::UnionType(instance) => {
+                    if let Ok(union_type) = instance.union_type(db) {
+                        Type::KnownInstance(KnownInstanceType::UnionType(
+                            UnionTypeInstance::new(
+                                db,
+                                instance._value_expr_types(db),
+                                Ok(union_type.apply_type_mapping_impl(db, type_mapping, tcx, visitor)),
+                                instance.binding_context(db),
+                            )
+                        ))
+                    } else {
+                        self
+                    }
+                },
+                KnownInstanceType::Annotated(instance) => {
+                    Type::KnownInstance(KnownInstanceType::Annotated(
+                        TypeInContext::new(
+                            db,
+                            instance.inner(db).apply_type_mapping_impl(db, type_mapping, tcx, visitor),
+                            instance.binding_context(db),
+                        )
+                    ))
+                },
+                KnownInstanceType::TypeGenericAlias(instance) => {
+                    Type::KnownInstance(KnownInstanceType::TypeGenericAlias(
+                        TypeInContext::new(
+                            db,
+                            instance.inner(db).apply_type_mapping_impl(db, type_mapping, tcx, visitor),
+                            instance.binding_context(db),
+                        )
+                    ))
+                },
+                KnownInstanceType::GenericAlias(instance) => {
+                    Type::KnownInstance(KnownInstanceType::GenericAlias(
+                        TypeInContext::new(
+                            db,
+                            instance.inner(db).apply_type_mapping_impl(db, type_mapping, tcx, visitor),
+                            instance.binding_context(db),
+                        )
+                    ))
+                },
+                KnownInstanceType::Callable(instance) => {
+                    Type::KnownInstance(KnownInstanceType::Callable(CallableTypeInstance::new(
+                        db,
+                        instance.callable_type(db).apply_type_mapping_impl(db, type_mapping, tcx, visitor),
+                        instance.binding_context(db),
+                    )))
+                },
+                KnownInstanceType::SubscriptedProtocol(_) |
+                KnownInstanceType::SubscriptedGeneric(_) |
+                KnownInstanceType::TypeAliasType(_) |
+                KnownInstanceType::Deprecated(_) |
+                KnownInstanceType::Field(_) |
+                KnownInstanceType::ConstraintSet(_) |
+                KnownInstanceType::GenericContext(_) |
+                KnownInstanceType::Specialization(_) |
+                KnownInstanceType::Literal(_) |
+                KnownInstanceType::LiteralStringAlias(_) |
+                KnownInstanceType::NewType(_) => {
+                    // TODO: For some of these, we may need to apply the type mapping to inner types.
+                    self
+                },
             }
 
             Type::FunctionLiteral(function) => {
@@ -7374,8 +7459,7 @@ impl<'db> Type<'db> {
             // some other generic context's specialization is applied to it.
             | Type::ClassLiteral(_)
             | Type::BoundSuper(_)
-            | Type::SpecialForm(_)
-            | Type::KnownInstance(_) => self,
+            | Type::SpecialForm(_) => self,
         }
     }
 
@@ -7512,6 +7596,53 @@ impl<'db> Type<'db> {
                 });
             }
 
+            Type::KnownInstance(known_instance) => match known_instance {
+                KnownInstanceType::UnionType(instance) => {
+                    if let Ok(union_type) = instance.union_type(db) {
+                        union_type.find_legacy_typevars_impl(
+                            db,
+                            binding_context,
+                            typevars,
+                            visitor,
+                        );
+                    }
+                }
+                KnownInstanceType::Annotated(ty) => {
+                    ty.inner(db)
+                        .find_legacy_typevars_impl(db, binding_context, typevars, visitor);
+                }
+                KnownInstanceType::Callable(instance) => {
+                    instance.callable_type(db).find_legacy_typevars_impl(
+                        db,
+                        binding_context,
+                        typevars,
+                        visitor,
+                    );
+                }
+                KnownInstanceType::TypeGenericAlias(ty) => {
+                    ty.inner(db)
+                        .find_legacy_typevars_impl(db, binding_context, typevars, visitor);
+                }
+                KnownInstanceType::GenericAlias(ty) => {
+                    ty.inner(db)
+                        .find_legacy_typevars_impl(db, binding_context, typevars, visitor);
+                }
+                KnownInstanceType::SubscriptedProtocol(_)
+                | KnownInstanceType::SubscriptedGeneric(_)
+                | KnownInstanceType::TypeVar(_)
+                | KnownInstanceType::TypeAliasType(_)
+                | KnownInstanceType::Deprecated(_)
+                | KnownInstanceType::Field(_)
+                | KnownInstanceType::ConstraintSet(_)
+                | KnownInstanceType::GenericContext(_)
+                | KnownInstanceType::Specialization(_)
+                | KnownInstanceType::Literal(_)
+                | KnownInstanceType::LiteralStringAlias(_)
+                | KnownInstanceType::NewType(_) => {
+                    // TODO: For some of these, we may need to try to find legacy typevars in inner types.
+                }
+            },
+
             Type::Dynamic(_)
             | Type::Never
             | Type::AlwaysTruthy
@@ -7539,7 +7670,6 @@ impl<'db> Type<'db> {
             | Type::EnumLiteral(_)
             | Type::BoundSuper(_)
             | Type::SpecialForm(_)
-            | Type::KnownInstance(_)
             | Type::TypedDict(_) => {}
         }
     }
@@ -8080,13 +8210,15 @@ pub enum KnownInstanceType<'db> {
     Literal(InternedType<'db>),
 
     /// A single instance of `typing.Annotated`
-    Annotated(InternedType<'db>),
+    Annotated(TypeInContext<'db>),
 
     /// An instance of `typing.GenericAlias` representing a `type[...]` expression.
-    TypeGenericAlias(InternedType<'db>),
+    TypeGenericAlias(TypeInContext<'db>),
+
+    GenericAlias(TypeInContext<'db>),
 
     /// An instance of `typing.GenericAlias` representing a `Callable[...]` expression.
-    Callable(CallableType<'db>),
+    Callable(CallableTypeInstance<'db>),
 
     /// A literal string which is the right-hand side of a PEP 613 `TypeAlias`.
     LiteralStringAlias(InternedType<'db>),
@@ -8128,14 +8260,16 @@ fn walk_known_instance_type<'db, V: visitor::TypeVisitor<'db> + ?Sized>(
                 visitor.visit_type(db, *union_type);
             }
         }
-        KnownInstanceType::Literal(ty)
-        | KnownInstanceType::Annotated(ty)
-        | KnownInstanceType::TypeGenericAlias(ty)
-        | KnownInstanceType::LiteralStringAlias(ty) => {
+        KnownInstanceType::Annotated(instance)
+        | KnownInstanceType::TypeGenericAlias(instance)
+        | KnownInstanceType::GenericAlias(instance) => {
+            visitor.visit_type(db, instance.inner(db));
+        }
+        KnownInstanceType::Literal(ty) | KnownInstanceType::LiteralStringAlias(ty) => {
             visitor.visit_type(db, ty.inner(db));
         }
-        KnownInstanceType::Callable(callable) => {
-            visitor.visit_callable_type(db, callable);
+        KnownInstanceType::Callable(instance) => {
+            visitor.visit_callable_type(db, instance.callable_type(db));
         }
         KnownInstanceType::NewType(newtype) => {
             if let ClassType::Generic(generic_alias) = newtype.base_class_type(db) {
@@ -8174,6 +8308,7 @@ impl<'db> KnownInstanceType<'db> {
             Self::Literal(ty) => Self::Literal(ty.normalized_impl(db, visitor)),
             Self::Annotated(ty) => Self::Annotated(ty.normalized_impl(db, visitor)),
             Self::TypeGenericAlias(ty) => Self::TypeGenericAlias(ty.normalized_impl(db, visitor)),
+            Self::GenericAlias(ty) => Self::GenericAlias(ty.normalized_impl(db, visitor)),
             Self::Callable(callable) => Self::Callable(callable.normalized_impl(db, visitor)),
             Self::LiteralStringAlias(ty) => {
                 Self::LiteralStringAlias(ty.normalized_impl(db, visitor))
@@ -8212,6 +8347,7 @@ impl<'db> KnownInstanceType<'db> {
             Self::Literal(_)
             | Self::Annotated(_)
             | Self::TypeGenericAlias(_)
+            | Self::GenericAlias(_)
             | Self::Callable(_) => KnownClass::GenericAlias,
             Self::LiteralStringAlias(_) => KnownClass::Str,
             Self::NewType(_) => KnownClass::NewType,
@@ -8306,7 +8442,7 @@ impl<'db> KnownInstanceType<'db> {
                         write!(
                             f,
                             "ty_extensions.Specialization{}",
-                            specialization.normalized(self.db).display_full(self.db)
+                            specialization.display_full(self.db)
                         )
                     }
                     KnownInstanceType::UnionType(_) => f.write_str("types.UnionType"),
@@ -8317,6 +8453,7 @@ impl<'db> KnownInstanceType<'db> {
                     KnownInstanceType::TypeGenericAlias(_) | KnownInstanceType::Callable(_) => {
                         f.write_str("GenericAlias")
                     }
+                    KnownInstanceType::GenericAlias(_) => f.write_str("GenericAlias(…)"), //TODO
                     KnownInstanceType::LiteralStringAlias(_) => f.write_str("str"),
                     KnownInstanceType::NewType(declaration) => {
                         write!(f, "<NewType pseudo-class '{}'>", declaration.name(self.db))
@@ -9499,6 +9636,11 @@ pub struct UnionTypeInstance<'db> {
     /// contains the first encountered error.
     #[returns(ref)]
     union_type: Result<Type<'db>, InvalidTypeExpressionError<'db>>,
+
+    /// The typevar binding context in which this union type instance was created.
+    /// For an implicit type alias like `ListOrSet = list[T] | set[T]`, this would
+    /// be the definition of `ListOrSet`.
+    binding_context: Option<Definition<'db>>,
 }
 
 impl get_size2::GetSize for UnionTypeInstance<'_> {}
@@ -9518,7 +9660,12 @@ impl<'db> UnionTypeInstance<'db> {
                 Ok(ty) => builder.add_in_place(ty),
                 Err(error) => {
                     return Type::KnownInstance(KnownInstanceType::UnionType(
-                        UnionTypeInstance::new(db, Some(value_expr_types), Err(error)),
+                        UnionTypeInstance::new(
+                            db,
+                            Some(value_expr_types),
+                            Err(error),
+                            typevar_binding_context,
+                        ),
                     ));
                 }
             }
@@ -9528,6 +9675,7 @@ impl<'db> UnionTypeInstance<'db> {
             db,
             Some(value_expr_types),
             Ok(builder.build()),
+            typevar_binding_context,
         )))
     }
 
@@ -9573,7 +9721,7 @@ impl<'db> UnionTypeInstance<'db> {
             .clone()
             .map(|ty| ty.normalized_impl(db, visitor));
 
-        Self::new(db, value_expr_types, union_type)
+        Self::new(db, value_expr_types, union_type, self.binding_context(db))
     }
 }
 
@@ -9596,6 +9744,56 @@ impl<'db> InternedType<'db> {
     }
 }
 
+/// A salsa-interned `Type` with an associated binding context for type variables.
+///
+/// # Ordering
+/// Ordering is based on the context's salsa-assigned id and not on its values.
+/// The id may change between runs, or when the context was garbage collected and recreated.
+#[salsa::interned(debug, heap_size=ruff_memory_usage::heap_size)]
+#[derive(PartialOrd, Ord)]
+pub struct TypeInContext<'db> {
+    inner: Type<'db>,
+    /// The typevar binding context in which this type was inferred.
+    binding_context: Option<Definition<'db>>,
+}
+
+impl get_size2::GetSize for TypeInContext<'_> {}
+
+impl<'db> TypeInContext<'db> {
+    pub(crate) fn normalized_impl(self, db: &'db dyn Db, visitor: &NormalizedVisitor<'db>) -> Self {
+        TypeInContext::new(
+            db,
+            self.inner(db).normalized_impl(db, visitor),
+            self.binding_context(db),
+        )
+    }
+}
+
+/// An instance of `typing.GenericAlias` representing a `Callable[...]` expression.
+///
+/// # Ordering
+/// Ordering is based on the context's salsa-assigned id and not on its values.
+/// The id may change between runs, or when the context was garbage collected and recreated.
+#[salsa::interned(debug, heap_size=ruff_memory_usage::heap_size)]
+#[derive(PartialOrd, Ord)]
+pub struct CallableTypeInstance<'db> {
+    callable_type: CallableType<'db>,
+    /// The binding context in which this callable type instance was inferred.
+    binding_context: Option<Definition<'db>>,
+}
+
+impl get_size2::GetSize for CallableTypeInstance<'_> {}
+
+impl<'db> CallableTypeInstance<'db> {
+    pub(crate) fn normalized_impl(self, db: &'db dyn Db, visitor: &NormalizedVisitor<'db>) -> Self {
+        CallableTypeInstance::new(
+            db,
+            self.callable_type(db).normalized_impl(db, visitor),
+            self.binding_context(db),
+        )
+    }
+}
+
 /// Error returned if a type is not awaitable.
 #[derive(Debug)]
 enum AwaitError<'db> {
@@ -11018,11 +11216,19 @@ impl<'db> CallableType<'db> {
         db: &'db dyn Db,
         self_type: Option<Type<'db>>,
     ) -> CallableType<'db> {
-        CallableType::new(db, self.signatures(db).bind_self(db, self_type), false)
+        CallableType::new(
+            db,
+            self.signatures(db).bind_self(db, self_type),
+            self.is_function_like(db),
+        )
     }
 
     pub(crate) fn apply_self(self, db: &'db dyn Db, self_type: Type<'db>) -> CallableType<'db> {
-        CallableType::new(db, self.signatures(db).apply_self(db, self_type), false)
+        CallableType::new(
+            db,
+            self.signatures(db).apply_self(db, self_type),
+            self.is_function_like(db),
+        )
     }
 
     /// Create a callable type which represents a fully-static "bottom" callable.

crates/ty_python_semantic/src/types/class.rs

@@ -362,6 +362,11 @@ impl<'db> VarianceInferable<'db> for GenericAlias<'db> {
     get_size2::GetSize,
 )]
 pub enum ClassType<'db> {
+    // `NonGeneric` is intended to mean that the `ClassLiteral` has no type parameters. There are
+    // places where we currently violate this rule (e.g. so that we print `Foo` instead of
+    // `Foo[Unknown]`), but most callers who need to make a `ClassType` from a `ClassLiteral`
+    // should use `ClassLiteral::default_specialization` instead of assuming
+    // `ClassType::NonGeneric`.
     NonGeneric(ClassLiteral<'db>),
     Generic(GenericAlias<'db>),
 }
@@ -1259,6 +1264,14 @@ impl MethodDecorator {
             (false, false) => Ok(Self::None),
         }
     }
+
+    pub(crate) const fn description(self) -> &'static str {
+        match self {
+            MethodDecorator::None => "an instance method",
+            MethodDecorator::ClassMethod => "a classmethod",
+            MethodDecorator::StaticMethod => "a staticmethod",
+        }
+    }
 }
 
 /// Kind-specific metadata for different types of fields
@@ -3664,12 +3677,6 @@ impl<'db> From<ClassLiteral<'db>> for Type<'db> {
     }
 }
 
-impl<'db> From<ClassLiteral<'db>> for ClassType<'db> {
-    fn from(class: ClassLiteral<'db>) -> ClassType<'db> {
-        ClassType::NonGeneric(class)
-    }
-}
-
 #[salsa::tracked]
 impl<'db> VarianceInferable<'db> for ClassLiteral<'db> {
     #[salsa::tracked(cycle_initial=crate::types::variance_cycle_initial, heap_size=ruff_memory_usage::heap_size)]

crates/ty_python_semantic/src/types/class_base.rs

@@ -185,6 +185,9 @@ impl<'db> ClassBase<'db> {
                 KnownInstanceType::TypeGenericAlias(_) => {
                     Self::try_from_type(db, KnownClass::Type.to_class_literal(db), subclass)
                 }
+                KnownInstanceType::GenericAlias(instance) => {
+                    Self::try_from_type(db, instance.inner(db), subclass)
+                }
                 KnownInstanceType::Annotated(ty) => {
                     // Unions are not supported in this position, so we only need to support
                     // something like `class C(Annotated[Base, "metadata"]): ...`, which we

crates/ty_python_semantic/src/types/constraints.rs

@@ -494,7 +494,11 @@ impl<'db> ConstrainedTypeVar<'db> {
                     })
                 }) =>
             {
-                return Node::AlwaysFalse;
+                return Node::new_constraint(
+                    db,
+                    ConstrainedTypeVar::new(db, typevar, Type::Never, Type::object()),
+                )
+                .negate(db);
             }
             _ => {}
         }
@@ -522,12 +526,6 @@ impl<'db> ConstrainedTypeVar<'db> {
             return Node::AlwaysFalse;
         }
 
-        // If the requested constraint is `Never ≤ T ≤ object`, then the typevar can be specialized
-        // to _any_ type, and the constraint does nothing.
-        if lower.is_never() && upper.is_object() {
-            return Node::AlwaysTrue;
-        }
-
         // We have an (arbitrary) ordering for typevars. If the upper and/or lower bounds are
         // typevars, we have to ensure that the bounds are "later" according to that order than the
         // typevar being constrained.
@@ -574,13 +572,21 @@ impl<'db> ConstrainedTypeVar<'db> {
                     db,
                     ConstrainedTypeVar::new(db, lower, Type::Never, Type::TypeVar(typevar)),
                 );
-                let upper = Self::new_node(db, typevar, Type::Never, upper);
+                let upper = if upper.is_object() {
+                    Node::AlwaysTrue
+                } else {
+                    Self::new_node(db, typevar, Type::Never, upper)
+                };
                 lower.and(db, upper)
             }
 
             // L ≤ T ≤ U == (L ≤ [T]) && (T ≤ [U])
             (_, Type::TypeVar(upper)) if typevar.can_be_bound_for(db, upper) => {
-                let lower = Self::new_node(db, typevar, lower, Type::object());
+                let lower = if lower.is_never() {
+                    Node::AlwaysTrue
+                } else {
+                    Self::new_node(db, typevar, lower, Type::object())
+                };
                 let upper = Node::new_constraint(
                     db,
                     ConstrainedTypeVar::new(db, upper, Type::TypeVar(typevar), Type::object()),
@@ -703,6 +709,15 @@ impl<'db> ConstrainedTypeVar<'db> {
                     );
                 }
 
+                if lower.is_never() && upper.is_object() {
+                    return write!(
+                        f,
+                        "({} {} *)",
+                        typevar.identity(self.db).display(self.db),
+                        if self.negated { "≠" } else { "=" }
+                    );
+                }
+
                 if self.negated {
                     f.write_str("¬")?;
                 }
@@ -1127,27 +1142,30 @@ impl<'db> Node<'db> {
     /// Invokes a callback for each of the representative types of a particular typevar for this
     /// constraint set.
     ///
-    /// There is a representative type for each distinct path from the BDD root to the `AlwaysTrue`
+    /// We first abstract the BDD so that it only mentions constraints on the requested typevar. We
+    /// then invoke your callback for each distinct path from the BDD root to the `AlwaysTrue`
     /// terminal. Each of those paths can be viewed as the conjunction of the individual
     /// constraints of each internal node that we traverse as we walk that path. We provide the
     /// lower/upper bound of this conjunction to your callback, allowing you to choose any suitable
     /// type in the range.
+    ///
+    /// If the abstracted BDD does not mention the typevar at all (i.e., it leaves the typevar
+    /// completely unconstrained), we will invoke your callback once with `None`.
     fn find_representative_types(
         self,
         db: &'db dyn Db,
         bound_typevar: BoundTypeVarIdentity<'db>,
-        mut f: impl FnMut(Type<'db>, Type<'db>),
+        mut f: impl FnMut(Option<(Type<'db>, Type<'db>)>),
     ) {
         self.retain_one(db, bound_typevar)
-            .find_representative_types_inner(db, Type::Never, Type::object(), &mut f);
+            .find_representative_types_inner(db, None, &mut f);
     }
 
     fn find_representative_types_inner(
         self,
         db: &'db dyn Db,
-        greatest_lower_bound: Type<'db>,
-        least_upper_bound: Type<'db>,
-        f: &mut dyn FnMut(Type<'db>, Type<'db>),
+        current_bounds: Option<(Type<'db>, Type<'db>)>,
+        f: &mut dyn FnMut(Option<(Type<'db>, Type<'db>)>),
     ) {
         match self {
             Node::AlwaysTrue => {
@@ -1157,12 +1175,16 @@ impl<'db> Node<'db> {
                 // If `lower ≰ upper`, then this path somehow represents in invalid specialization.
                 // That should have been removed from the BDD domain as part of the simplification
                 // process.
-                debug_assert!(greatest_lower_bound.is_subtype_of(db, least_upper_bound));
+                debug_assert!(current_bounds.is_none_or(
+                    |(greatest_lower_bound, least_upper_bound)| {
+                        greatest_lower_bound.is_subtype_of(db, least_upper_bound)
+                    }
+                ));
 
                 // We've been tracking the lower and upper bound that the types for this path must
                 // satisfy. Pass those bounds along and let the caller choose a representative type
                 // from within that range.
-                f(greatest_lower_bound, least_upper_bound);
+                f(current_bounds);
             }
 
             Node::AlwaysFalse => {
@@ -1171,6 +1193,9 @@ impl<'db> Node<'db> {
             }
 
             Node::Interior(interior) => {
+                let (greatest_lower_bound, least_upper_bound) =
+                    current_bounds.unwrap_or((Type::Never, Type::object()));
+
                 // For an interior node, there are two outgoing paths: one for the `if_true`
                 // branch, and one for the `if_false` branch.
                 //
@@ -1185,8 +1210,7 @@ impl<'db> Node<'db> {
                     IntersectionType::from_elements(db, [least_upper_bound, constraint.upper(db)]);
                 interior.if_true(db).find_representative_types_inner(
                     db,
-                    new_greatest_lower_bound,
-                    new_least_upper_bound,
+                    Some((new_greatest_lower_bound, new_least_upper_bound)),
                     f,
                 );
 
@@ -1202,8 +1226,7 @@ impl<'db> Node<'db> {
                 // path.
                 interior.if_false(db).find_representative_types_inner(
                     db,
-                    greatest_lower_bound,
-                    least_upper_bound,
+                    Some((greatest_lower_bound, least_upper_bound)),
                     f,
                 );
             }
@@ -2239,6 +2262,9 @@ impl<'db> ConstraintAssignment<'db> {
 ///
 /// We support several kinds of sequent:
 ///
+/// - `¬C₁ → false`: This indicates that `C₁` is always true. Any path that assumes it is false is
+///   impossible and can be pruned.
+///
 /// - `C₁ ∧ C₂ → false`: This indicates that `C₁` and `C₂` are disjoint: it is not possible for
 ///   both to hold. Any path that assumes both is impossible and can be pruned.
 ///
@@ -2250,8 +2276,10 @@ impl<'db> ConstraintAssignment<'db> {
 ///   holds but `D` does _not_ is impossible and can be pruned.
 #[derive(Debug, Default, Eq, PartialEq, get_size2::GetSize, salsa::Update)]
 struct SequentMap<'db> {
+    /// Sequents of the form `¬C₁ → false`
+    single_tautologies: FxHashSet<ConstrainedTypeVar<'db>>,
     /// Sequents of the form `C₁ ∧ C₂ → false`
-    impossibilities: FxHashSet<(ConstrainedTypeVar<'db>, ConstrainedTypeVar<'db>)>,
+    pair_impossibilities: FxHashSet<(ConstrainedTypeVar<'db>, ConstrainedTypeVar<'db>)>,
     /// Sequents of the form `C₁ ∧ C₂ → D`
     pair_implications: FxHashMap<
         (ConstrainedTypeVar<'db>, ConstrainedTypeVar<'db>),
@@ -2310,13 +2338,17 @@ impl<'db> SequentMap<'db> {
         }
     }
 
-    fn add_impossibility(
+    fn add_single_tautology(&mut self, ante: ConstrainedTypeVar<'db>) {
+        self.single_tautologies.insert(ante);
+    }
+
+    fn add_pair_impossibility(
         &mut self,
         db: &'db dyn Db,
         ante1: ConstrainedTypeVar<'db>,
         ante2: ConstrainedTypeVar<'db>,
     ) {
-        self.impossibilities
+        self.pair_impossibilities
             .insert(Self::pair_key(db, ante1, ante2));
     }
 
@@ -2352,6 +2384,15 @@ impl<'db> SequentMap<'db> {
     }
 
     fn add_sequents_for_single(&mut self, db: &'db dyn Db, constraint: ConstrainedTypeVar<'db>) {
+        // If this constraint binds its typevar to `Never ≤ T ≤ object`, then the typevar can take
+        // on any type, and the constraint is always satisfied.
+        let lower = constraint.lower(db);
+        let upper = constraint.upper(db);
+        if lower.is_never() && upper.is_object() {
+            self.add_single_tautology(constraint);
+            return;
+        }
+
         // If the lower or upper bound of this constraint is a typevar, we can propagate the
         // constraint:
         //
@@ -2362,8 +2403,6 @@ impl<'db> SequentMap<'db> {
         // Technically, (1) also allows `(S = T) → (S = S)`, but the rhs of that is vacuously true,
         // so we don't add a sequent for that case.
 
-        let lower = constraint.lower(db);
-        let upper = constraint.upper(db);
         let post_constraint = match (lower, upper) {
             // Case 1
             (Type::TypeVar(lower_typevar), Type::TypeVar(upper_typevar)) => {
@@ -2568,7 +2607,7 @@ impl<'db> SequentMap<'db> {
                 self.enqueue_constraint(intersection_constraint);
             }
             None => {
-                self.add_impossibility(db, left_constraint, right_constraint);
+                self.add_pair_impossibility(db, left_constraint, right_constraint);
             }
         }
     }
@@ -2593,7 +2632,7 @@ impl<'db> SequentMap<'db> {
                     }
                 };
 
-                for (ante1, ante2) in &self.map.impossibilities {
+                for (ante1, ante2) in &self.map.pair_impossibilities {
                     maybe_write_prefix(f)?;
                     write!(
                         f,
@@ -2726,7 +2765,15 @@ impl<'db> PathAssignments<'db> {
         // don't anticipate the sequent maps to be very large. We might consider avoiding the
         // brute-force search.
 
-        for (ante1, ante2) in &map.impossibilities {
+        for ante in &map.single_tautologies {
+            if self.assignment_holds(ante.when_false()) {
+                // The sequent map says (ante1) is always true, and the current path asserts that
+                // it's false.
+                return Err(PathAssignmentConflict);
+            }
+        }
+
+        for (ante1, ante2) in &map.pair_impossibilities {
             if self.assignment_holds(ante1.when_true()) && self.assignment_holds(ante2.when_true())
             {
                 // The sequent map says (ante1 ∧ ante2) is an impossible combination, and the
@@ -3088,8 +3135,8 @@ impl<'db> GenericContext<'db> {
             });
 
         // Then we find all of the "representative types" for each typevar in the constraint set.
-        let mut types = vec![Type::Never; self.len(db)];
-        for (i, bound_typevar) in self.variables(db).enumerate() {
+        let mut error_occurred = false;
+        let types = self.variables(db).map(|bound_typevar| {
             // Each representative type represents one of the ways that the typevar can satisfy the
             // constraint, expressed as a lower/upper bound on the types that the typevar can
             // specialize to.
@@ -3101,40 +3148,55 @@ impl<'db> GenericContext<'db> {
             // _each_ of the paths into separate specializations, but it's not clear what we would
             // do with that, so instead we just report the ambiguity as a specialization failure.
             let mut satisfied = false;
+            let mut unconstrained = false;
             let mut greatest_lower_bound = Type::Never;
             let mut least_upper_bound = Type::object();
-            abstracted.find_representative_types(
-                db,
-                bound_typevar.identity(db),
-                |lower_bound, upper_bound| {
-                    satisfied = true;
-                    greatest_lower_bound =
-                        UnionType::from_elements(db, [greatest_lower_bound, lower_bound]);
-                    least_upper_bound =
-                        IntersectionType::from_elements(db, [least_upper_bound, upper_bound]);
-                },
-            );
+            abstracted.find_representative_types(db, bound_typevar.identity(db), |bounds| {
+                satisfied = true;
+                match bounds {
+                    Some((lower_bound, upper_bound)) => {
+                        greatest_lower_bound =
+                            UnionType::from_elements(db, [greatest_lower_bound, lower_bound]);
+                        least_upper_bound =
+                            IntersectionType::from_elements(db, [least_upper_bound, upper_bound]);
+                    }
+                    None => {
+                        unconstrained = true;
+                    }
+                }
+            });
 
             // If there are no satisfiable paths in the BDD, then there is no valid specialization
             // for this constraint set.
             if !satisfied {
                 // TODO: Construct a useful error here
-                return Err(());
+                error_occurred = true;
+                return None;
+            }
+
+            // The BDD is satisfiable, but the typevar is unconstrained, then we use `None` to tell
+            // specialize_recursive to fall back on the typevar's default.
+            if unconstrained {
+                return None;
             }
 
             // If `lower ≰ upper`, then there is no type that satisfies all of the paths in the
             // BDD. That's an ambiguous specialization, as described above.
             if !greatest_lower_bound.is_subtype_of(db, least_upper_bound) {
-                // TODO: Construct a useful error here
-                return Err(());
+                error_occurred = true;
+                return None;
             }
 
             // Of all of the types that satisfy all of the paths in the BDD, we choose the
             // "largest" one (i.e., "closest to `object`") as the specialization.
-            types[i] = least_upper_bound;
-        }
+            Some(least_upper_bound)
+        });
 
-        Ok(self.specialize_recursive(db, types.into_boxed_slice()))
+        let specialization = self.specialize_recursive(db, types);
+        if error_occurred {
+            return Err(());
+        }
+        Ok(specialization)
     }
 }
 

crates/ty_python_semantic/src/types/diagnostic.rs

@@ -8,13 +8,13 @@ use super::{
 use crate::diagnostic::did_you_mean;
 use crate::diagnostic::format_enumeration;
 use crate::lint::{Level, LintRegistryBuilder, LintStatus};
+use crate::place::Place;
 use crate::semantic_index::definition::{Definition, DefinitionKind};
 use crate::semantic_index::place::{PlaceTable, ScopedPlaceId};
 use crate::semantic_index::{global_scope, place_table, use_def_map};
 use crate::suppression::FileSuppressionId;
-use crate::types::KnownInstanceType;
 use crate::types::call::CallError;
-use crate::types::class::{DisjointBase, DisjointBaseKind, Field};
+use crate::types::class::{DisjointBase, DisjointBaseKind, Field, MethodDecorator};
 use crate::types::function::{FunctionType, KnownFunction};
 use crate::types::liskov::{MethodKind, SynthesizedMethodKind};
 use crate::types::string_annotation::{
@@ -27,6 +27,7 @@ use crate::types::{
     ProtocolInstanceType, SpecialFormType, SubclassOfInner, Type, TypeContext, binding_type,
     infer_isolated_expression, protocol_class::ProtocolClass,
 };
+use crate::types::{KnownInstanceType, MemberLookupPolicy};
 use crate::{Db, DisplaySettings, FxIndexMap, Module, ModuleName, Program, declare_lint};
 use itertools::Itertools;
 use ruff_db::{
@@ -3519,6 +3520,27 @@ pub(super) fn report_invalid_method_override<'db>(
         "Definition is incompatible with `{overridden_method}`"
     ));
 
+    let class_member = |cls: ClassType<'db>| {
+        cls.class_member(db, member, MemberLookupPolicy::default())
+            .place
+    };
+
+    if let Place::Defined(Type::FunctionLiteral(subclass_function), _, _) = class_member(subclass)
+        && let Place::Defined(Type::FunctionLiteral(superclass_function), _, _) =
+            class_member(superclass)
+        && let Ok(superclass_function_kind) =
+            MethodDecorator::try_from_fn_type(db, superclass_function)
+        && let Ok(subclass_function_kind) = MethodDecorator::try_from_fn_type(db, subclass_function)
+        && superclass_function_kind != subclass_function_kind
+    {
+        diagnostic.info(format_args!(
+            "`{class_name}.{member}` is {subclass_function_kind} \
+            but `{overridden_method}` is {superclass_function_kind}",
+            superclass_function_kind = superclass_function_kind.description(),
+            subclass_function_kind = subclass_function_kind.description(),
+        ));
+    }
+
     diagnostic.info("This violates the Liskov Substitution Principle");
 
     if !subclass_definition_kind.is_function_def()
@@ -3545,9 +3567,11 @@ pub(super) fn report_invalid_method_override<'db>(
                         .full_range(db, &parsed_module(db, superclass_scope.file(db)).load(db)),
                 );
 
-                let superclass_function_span = superclass_type
-                    .as_bound_method()
-                    .and_then(|method| signature_span(method.function(db)));
+                let superclass_function_span = match superclass_type {
+                    Type::FunctionLiteral(function) => signature_span(function),
+                    Type::BoundMethod(method) => signature_span(method.function(db)),
+                    _ => None,
+                };
 
                 let superclass_definition_kind = definition.kind(db);
 

crates/ty_python_semantic/src/types/display.rs

@@ -107,6 +107,8 @@ pub struct TypeDisplayDetails<'db> {
     pub targets: Vec<TextRange>,
     /// Metadata for each range
     pub details: Vec<TypeDetail<'db>>,
+    /// Whether the label is valid Python syntax
+    pub is_valid_syntax: bool,
 }
 
 /// Abstraction over "are we doing normal formatting, or tracking ranges with metadata?"
@@ -119,6 +121,7 @@ struct TypeDetailsWriter<'db> {
     label: String,
     targets: Vec<TextRange>,
     details: Vec<TypeDetail<'db>>,
+    is_valid_syntax: bool,
 }
 
 impl<'db> TypeDetailsWriter<'db> {
@@ -127,6 +130,7 @@ impl<'db> TypeDetailsWriter<'db> {
             label: String::new(),
             targets: Vec::new(),
             details: Vec::new(),
+            is_valid_syntax: true,
         }
     }
 
@@ -136,6 +140,7 @@ impl<'db> TypeDetailsWriter<'db> {
             label: self.label,
             targets: self.targets,
             details: self.details,
+            is_valid_syntax: self.is_valid_syntax,
         }
     }
 
@@ -192,6 +197,13 @@ impl<'a, 'b, 'db> TypeWriter<'a, 'b, 'db> {
         self.with_detail(TypeDetail::Type(ty))
     }
 
+    fn set_invalid_syntax(&mut self) {
+        match self {
+            TypeWriter::Formatter(_) => {}
+            TypeWriter::Details(details) => details.is_valid_syntax = false,
+        }
+    }
+
     fn join<'c>(&'c mut self, separator: &'static str) -> Join<'a, 'b, 'c, 'db> {
         Join {
             fmt: self,
@@ -539,6 +551,7 @@ impl<'db> FmtDetailed<'db> for ClassDisplay<'db> {
             let line_index = line_index(self.db, file);
             let class_offset = self.class.header_range(self.db).start();
             let line_number = line_index.line_index(class_offset);
+            f.set_invalid_syntax();
             write!(f, " @ {path}:{line_number}")?;
         }
         Ok(())
@@ -599,6 +612,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                         .fmt_detailed(f),
                 },
                 Protocol::Synthesized(synthetic) => {
+                    f.set_invalid_syntax();
                     f.write_char('<')?;
                     f.with_type(Type::SpecialForm(SpecialFormType::Protocol))
                         .write_str("Protocol")?;
@@ -618,6 +632,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
             },
             Type::PropertyInstance(_) => f.with_type(self.ty).write_str("property"),
             Type::ModuleLiteral(module) => {
+                f.set_invalid_syntax();
                 write!(
                     f.with_type(self.ty),
                     "<module '{}'>",
@@ -625,6 +640,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                 )
             }
             Type::ClassLiteral(class) => {
+                f.set_invalid_syntax();
                 let mut f = f.with_type(self.ty);
                 f.write_str("<class '")?;
                 class
@@ -633,6 +649,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                 f.write_str("'>")
             }
             Type::GenericAlias(generic) => {
+                f.set_invalid_syntax();
                 let mut f = f.with_type(self.ty);
                 f.write_str("<class '")?;
                 generic
@@ -691,7 +708,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                             db: self.db,
                             settings: self.settings.clone(),
                         };
-
+                        f.set_invalid_syntax();
                         f.write_str("bound method ")?;
                         self_ty
                             .display_with(self.db, self.settings.singleline())
@@ -729,51 +746,57 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                     }
                 }
             }
-            Type::KnownBoundMethod(KnownBoundMethodType::FunctionTypeDunderGet(function)) => {
-                write!(
-                    f,
-                    "<method-wrapper `__get__` of `{function}`>",
-                    function = function.name(self.db),
-                )
+            Type::KnownBoundMethod(method_type) => {
+                f.set_invalid_syntax();
+                match method_type {
+                    KnownBoundMethodType::FunctionTypeDunderGet(function) => {
+                        write!(
+                            f,
+                            "<method-wrapper `__get__` of `{function}`>",
+                            function = function.name(self.db),
+                        )
+                    }
+                    KnownBoundMethodType::FunctionTypeDunderCall(function) => {
+                        write!(
+                            f,
+                            "<method-wrapper `__call__` of `{function}`>",
+                            function = function.name(self.db),
+                        )
+                    }
+                    KnownBoundMethodType::PropertyDunderGet(_) => {
+                        f.write_str("<method-wrapper `__get__` of `property` object>")
+                    }
+                    KnownBoundMethodType::PropertyDunderSet(_) => {
+                        f.write_str("<method-wrapper `__set__` of `property` object>")
+                    }
+                    KnownBoundMethodType::StrStartswith(_) => {
+                        f.write_str("<method-wrapper `startswith` of `str` object>")
+                    }
+                    KnownBoundMethodType::ConstraintSetRange => {
+                        f.write_str("bound method `ConstraintSet.range`")
+                    }
+                    KnownBoundMethodType::ConstraintSetAlways => {
+                        f.write_str("bound method `ConstraintSet.always`")
+                    }
+                    KnownBoundMethodType::ConstraintSetNever => {
+                        f.write_str("bound method `ConstraintSet.never`")
+                    }
+                    KnownBoundMethodType::ConstraintSetImpliesSubtypeOf(_) => {
+                        f.write_str("bound method `ConstraintSet.implies_subtype_of`")
+                    }
+                    KnownBoundMethodType::ConstraintSetSatisfies(_) => {
+                        f.write_str("bound method `ConstraintSet.satisfies`")
+                    }
+                    KnownBoundMethodType::ConstraintSetSatisfiedByAllTypeVars(_) => {
+                        f.write_str("bound method `ConstraintSet.satisfied_by_all_typevars`")
+                    }
+                    KnownBoundMethodType::GenericContextSpecializeConstrained(_) => {
+                        f.write_str("bound method `GenericContext.specialize_constrained`")
+                    }
+                }
             }
-            Type::KnownBoundMethod(KnownBoundMethodType::FunctionTypeDunderCall(function)) => {
-                write!(
-                    f,
-                    "<method-wrapper `__call__` of `{function}`>",
-                    function = function.name(self.db),
-                )
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::PropertyDunderGet(_)) => {
-                f.write_str("<method-wrapper `__get__` of `property` object>")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::PropertyDunderSet(_)) => {
-                f.write_str("<method-wrapper `__set__` of `property` object>")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::StrStartswith(_)) => {
-                f.write_str("<method-wrapper `startswith` of `str` object>")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetRange) => {
-                f.write_str("bound method `ConstraintSet.range`")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetAlways) => {
-                f.write_str("bound method `ConstraintSet.always`")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetNever) => {
-                f.write_str("bound method `ConstraintSet.never`")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetImpliesSubtypeOf(_)) => {
-                f.write_str("bound method `ConstraintSet.implies_subtype_of`")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetSatisfies(_)) => {
-                f.write_str("bound method `ConstraintSet.satisfies`")
-            }
-            Type::KnownBoundMethod(KnownBoundMethodType::ConstraintSetSatisfiedByAllTypeVars(
-                _,
-            )) => f.write_str("bound method `ConstraintSet.satisfied_by_all_typevars`"),
-            Type::KnownBoundMethod(KnownBoundMethodType::GenericContextSpecializeConstrained(
-                _,
-            )) => f.write_str("bound method `GenericContext.specialize_constrained`"),
             Type::WrapperDescriptor(kind) => {
+                f.set_invalid_syntax();
                 let (method, object) = match kind {
                     WrapperDescriptorKind::FunctionTypeDunderGet => ("__get__", "function"),
                     WrapperDescriptorKind::PropertyDunderGet => ("__get__", "property"),
@@ -782,9 +805,11 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                 write!(f, "<wrapper-descriptor `{method}` of `{object}` objects>")
             }
             Type::DataclassDecorator(_) => {
+                f.set_invalid_syntax();
                 f.write_str("<decorator produced by dataclass-like function>")
             }
             Type::DataclassTransformer(_) => {
+                f.set_invalid_syntax();
                 f.write_str("<decorator produced by typing.dataclass_transform>")
             }
             Type::Union(union) => union
@@ -828,11 +853,13 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                 write!(f, ".{}", enum_literal.name(self.db))
             }
             Type::TypeVar(bound_typevar) => {
+                f.set_invalid_syntax();
                 write!(f, "{}", bound_typevar.identity(self.db).display(self.db))
             }
             Type::AlwaysTruthy => f.with_type(self.ty).write_str("AlwaysTruthy"),
             Type::AlwaysFalsy => f.with_type(self.ty).write_str("AlwaysFalsy"),
             Type::BoundSuper(bound_super) => {
+                f.set_invalid_syntax();
                 f.write_str("<super: ")?;
                 Type::from(bound_super.pivot_class(self.db))
                     .display_with(self.db, self.settings.singleline())
@@ -852,6 +879,7 @@ impl<'db> FmtDetailed<'db> for DisplayRepresentation<'db> {
                     .display_with(self.db, self.settings.singleline())
                     .fmt_detailed(f)?;
                 if let Some(name) = type_is.place_name(self.db) {
+                    f.set_invalid_syntax();
                     f.write_str(" @ ")?;
                     f.write_str(&name)?;
                 }
@@ -1029,6 +1057,7 @@ impl<'db> FmtDetailed<'db> for DisplayOverloadLiteral<'db> {
             settings: self.settings.clone(),
         };
 
+        f.set_invalid_syntax();
         f.write_str("def ")?;
         write!(f, "{}", self.literal.name(self.db))?;
         type_parameters.fmt_detailed(f)?;
@@ -1075,7 +1104,7 @@ impl<'db> FmtDetailed<'db> for DisplayFunctionType<'db> {
                     db: self.db,
                     settings: self.settings.clone(),
                 };
-
+                f.set_invalid_syntax();
                 f.write_str("def ")?;
                 write!(f, "{}", self.ty.name(self.db))?;
                 type_parameters.fmt_detailed(f)?;
@@ -1256,6 +1285,7 @@ impl<'db> DisplayGenericContext<'_, 'db> {
             if idx > 0 {
                 f.write_str(", ")?;
             }
+            f.set_invalid_syntax();
             f.write_str(bound_typevar.typevar(self.db).name(self.db))?;
         }
         f.write_char(']')
@@ -1268,6 +1298,7 @@ impl<'db> DisplayGenericContext<'_, 'db> {
             if idx > 0 {
                 f.write_str(", ")?;
             }
+            f.set_invalid_syntax();
             write!(f, "{}", bound_typevar.identity(self.db).display(self.db))?;
         }
         f.write_char(']')
@@ -1358,6 +1389,7 @@ impl<'db> DisplaySpecialization<'db> {
             if idx > 0 {
                 f.write_str(", ")?;
             }
+            f.set_invalid_syntax();
             write!(f, "{}", bound_typevar.identity(self.db).display(self.db))?;
             f.write_str(" = ")?;
             ty.display_with(self.db, self.settings.clone())
@@ -1505,6 +1537,7 @@ impl<'db> FmtDetailed<'db> for DisplaySignature<'_, 'db> {
     fn fmt_detailed(&self, f: &mut TypeWriter<'_, '_, 'db>) -> fmt::Result {
         // Immediately write a marker signaling we're starting a signature
         let _ = f.with_detail(TypeDetail::SignatureStart);
+        f.set_invalid_syntax();
         // When we exit this function, write a marker signaling we're ending a signature
         let mut f = f.with_detail(TypeDetail::SignatureEnd);
         let multiline = self.settings.multiline && self.parameters.len() > 1;
@@ -1694,6 +1727,7 @@ impl<'db> FmtDetailed<'db> for DisplayOmitted {
         } else {
             self.plural
         };
+        f.set_invalid_syntax();
         write!(f, "... omitted {} {}", self.count, noun)
     }
 }
@@ -1908,6 +1942,7 @@ impl<'db> FmtDetailed<'db> for DisplayIntersectionType<'_, 'db> {
                     }),
             );
 
+        f.set_invalid_syntax();
         f.join(" & ").entries(tys).finish()
     }
 }
@@ -1960,6 +1995,7 @@ struct DisplayMaybeParenthesizedType<'db> {
 impl<'db> FmtDetailed<'db> for DisplayMaybeParenthesizedType<'db> {
     fn fmt_detailed(&self, f: &mut TypeWriter<'_, '_, 'db>) -> fmt::Result {
         let write_parentheses = |f: &mut TypeWriter<'_, '_, 'db>| {
+            f.set_invalid_syntax();
             f.write_char('(')?;
             self.ty
                 .display_with(self.db, self.settings.clone())

crates/ty_python_semantic/src/types/generics.rs

@@ -522,14 +522,15 @@ impl<'db> GenericContext<'db> {
     /// Creates a specialization of this generic context. Panics if the length of `types` does not
     /// match the number of typevars in the generic context.
     ///
-    /// You are allowed to provide types that mention the typevars in this generic context.
-    pub(crate) fn specialize_recursive(
-        self,
-        db: &'db dyn Db,
-        mut types: Box<[Type<'db>]>,
-    ) -> Specialization<'db> {
+    /// If any provided type is `None`, we will use the corresponding typevar's default type. You
+    /// are allowed to provide types that mention the typevars in this generic context.
+    pub(crate) fn specialize_recursive<I>(self, db: &'db dyn Db, types: I) -> Specialization<'db>
+    where
+        I: IntoIterator<Item = Option<Type<'db>>>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let mut types = self.fill_in_defaults(db, types);
         let len = types.len();
-        assert!(self.len(db) == len);
         loop {
             let mut any_changed = false;
             for i in 0..len {
@@ -564,10 +565,7 @@ impl<'db> GenericContext<'db> {
         Specialization::new(db, self, Box::from([element_type]), None, Some(tuple))
     }
 
-    /// Creates a specialization of this generic context. Panics if the length of `types` does not
-    /// match the number of typevars in the generic context. If any provided type is `None`, we
-    /// will use the corresponding typevar's default type.
-    pub(crate) fn specialize_partial<I>(self, db: &'db dyn Db, types: I) -> Specialization<'db>
+    fn fill_in_defaults<I>(self, db: &'db dyn Db, types: I) -> Box<[Type<'db>]>
     where
         I: IntoIterator<Item = Option<Type<'db>>>,
         I::IntoIter: ExactSizeIterator,
@@ -610,7 +608,18 @@ impl<'db> GenericContext<'db> {
             expanded[idx] = default;
         }
 
-        Specialization::new(db, self, expanded.into_boxed_slice(), None, None)
+        expanded.into_boxed_slice()
+    }
+
+    /// Creates a specialization of this generic context. Panics if the length of `types` does not
+    /// match the number of typevars in the generic context. If any provided type is `None`, we
+    /// will use the corresponding typevar's default type.
+    pub(crate) fn specialize_partial<I>(self, db: &'db dyn Db, types: I) -> Specialization<'db>
+    where
+        I: IntoIterator<Item = Option<Type<'db>>>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        Specialization::new(db, self, self.fill_in_defaults(db, types), None, None)
     }
 
     pub(crate) fn normalized_impl(self, db: &'db dyn Db, visitor: &NormalizedVisitor<'db>) -> Self {
@@ -1045,11 +1054,6 @@ impl<'db> Specialization<'db> {
         Specialization::new(db, self.generic_context(db), types, None, None)
     }
 
-    #[must_use]
-    pub(crate) fn normalized(self, db: &'db dyn Db) -> Self {
-        self.normalized_impl(db, &NormalizedVisitor::default())
-    }
-
     pub(crate) fn normalized_impl(self, db: &'db dyn Db, visitor: &NormalizedVisitor<'db>) -> Self {
         let types: Box<[_]> = self
             .types(db)

crates/ty_python_semantic/src/types/infer/builder.rs

@@ -101,14 +101,14 @@ use crate::types::typed_dict::{
 };
 use crate::types::visitor::any_over_type;
 use crate::types::{
-    CallDunderError, CallableBinding, CallableType, CallableTypes, ClassLiteral, ClassType,
-    DataclassParams, DynamicType, InternedType, IntersectionBuilder, IntersectionType, KnownClass,
-    KnownInstanceType, LintDiagnosticGuard, MemberLookupPolicy, MetaclassCandidate,
-    PEP695TypeAliasType, Parameter, ParameterForm, Parameters, SpecialFormType, SubclassOfType,
-    TrackedConstraintSet, Truthiness, Type, TypeAliasType, TypeAndQualifiers, TypeContext,
-    TypeQualifiers, TypeVarBoundOrConstraintsEvaluation, TypeVarDefaultEvaluation, TypeVarIdentity,
-    TypeVarInstance, TypeVarKind, TypeVarVariance, TypedDictType, UnionBuilder, UnionType,
-    UnionTypeInstance, binding_type, liskov, todo_type,
+    CallDunderError, CallableBinding, CallableType, CallableTypeInstance, CallableTypes,
+    ClassLiteral, ClassType, DataclassParams, DynamicType, InternedType, IntersectionBuilder,
+    IntersectionType, KnownClass, KnownInstanceType, LintDiagnosticGuard, MemberLookupPolicy,
+    MetaclassCandidate, PEP695TypeAliasType, Parameter, ParameterForm, Parameters, SpecialFormType,
+    SubclassOfType, TrackedConstraintSet, Truthiness, Type, TypeAliasType, TypeAndQualifiers,
+    TypeContext, TypeInContext, TypeQualifiers, TypeVarBoundOrConstraintsEvaluation,
+    TypeVarDefaultEvaluation, TypeVarIdentity, TypeVarInstance, TypeVarKind, TypeVarVariance,
+    TypedDictType, UnionBuilder, UnionType, UnionTypeInstance, binding_type, liskov, todo_type,
 };
 use crate::types::{ClassBase, add_inferred_python_version_hint_to_diagnostic};
 use crate::unpack::{EvaluationMode, UnpackPosition};
@@ -4739,6 +4739,12 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 unpacked.expression_type(target)
             }
             TargetKind::Single => {
+                // This could be an implicit type alias (OptionalList = list[T] | None). Use the definition
+                // of `OptionalList` as the binding context while inferring the RHS (`list[T] | None`), in
+                // order to bind `T` to `OptionalList`.
+                let previous_typevar_binding_context =
+                    self.typevar_binding_context.replace(definition);
+
                 let value_ty = if let Some(standalone_expression) = self.index.try_expression(value)
                 {
                     self.infer_standalone_expression_impl(value, standalone_expression, tcx)
@@ -4777,6 +4783,8 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     self.infer_expression(value, tcx)
                 };
 
+                self.typevar_binding_context = previous_typevar_binding_context;
+
                 // `TYPE_CHECKING` is a special variable that should only be assigned `False`
                 // at runtime, but is always considered `True` in type checking.
                 // See mdtest/known_constants.md#user-defined-type_checking for details.
@@ -5523,11 +5531,18 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 self.deferred_state = DeferredExpressionState::Deferred;
             }
 
+            // This might be a PEP-613 type alias (`OptionalList: TypeAlias = list[T] | None`). Use
+            // the definition of `OptionalList` as the binding context while inferring the
+            // RHS (`list[T] | None`), in order to bind `T` to `OptionalList`.
+            let previous_typevar_binding_context = self.typevar_binding_context.replace(definition);
+
             let inferred_ty = self.infer_maybe_standalone_expression(
                 value,
                 TypeContext::new(Some(declared.inner_type())),
             );
 
+            self.typevar_binding_context = previous_typevar_binding_context;
+
             self.deferred_state = previous_deferred_state;
 
             self.dataclass_field_specifiers.clear();
@@ -10794,7 +10809,52 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
 
     fn infer_subscript_load(&mut self, subscript: &ast::ExprSubscript) -> Type<'db> {
         let value_ty = self.infer_expression(&subscript.value, TypeContext::default());
-        self.infer_subscript_load_impl(value_ty, subscript)
+
+        // If we have an implicit type alias like `MyList = list[T]`, and if `MyList` is being
+        // used in another implicit type alias like `Numbers = MyList[int]`, then we infer the
+        // right hand side as a value expression, and need to handle the specialization here.
+        if let Type::KnownInstance(KnownInstanceType::GenericAlias(alias)) = value_ty {
+            return Type::KnownInstance(KnownInstanceType::GenericAlias(TypeInContext::new(
+                self.db(),
+                self.infer_explicitly_specialized_type_alias(
+                    subscript,
+                    value_ty,
+                    alias.binding_context(self.db()),
+                    false,
+                ),
+                self.typevar_binding_context,
+            )));
+        }
+
+        // if let Type::GenericAlias(alias) = value_ty {
+        //     return Type::KnownInstance(KnownInstanceType::GenericAlias(TypeInContext::new(
+        //         self.db(),
+        //         self.infer_explicitly_specialized_type_alias(
+        //             subscript,
+        //             value_ty,
+        //             Some(alias.definition(self.db())),
+        //             false,
+        //         ),
+        //         self.typevar_binding_context,
+        //     )));
+        // }
+
+        let result_ty = self.infer_subscript_load_impl(value_ty, subscript);
+
+        // let result_ty = if result_ty.is_generic_alias() {
+        //     Type::KnownInstance(KnownInstanceType::GenericAlias(TypeInContext::new(
+        //         self.db(),
+        //         result_ty,
+        //         self.typevar_binding_context,
+        //     )))
+        // } else {
+        // result_ty
+        // };
+
+        // eprintln!("Subscripting type: {}", value_ty.display(self.db()));
+        // eprintln!("Inferred subscript type: {}", result_ty.display(self.db()));
+
+        result_ty
     }
 
     fn infer_subscript_load_impl(
@@ -10848,7 +10908,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 } else if class.is_known(self.db(), KnownClass::Type) {
                     let argument_ty = self.infer_type_expression(slice);
                     return Type::KnownInstance(KnownInstanceType::TypeGenericAlias(
-                        InternedType::new(self.db(), argument_ty),
+                        TypeInContext::new(self.db(), argument_ty, self.typevar_binding_context),
                     ));
                 }
 
@@ -10926,9 +10986,10 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
 
                 let ty = self.infer_type_expression(type_expr);
 
-                return Type::KnownInstance(KnownInstanceType::Annotated(InternedType::new(
+                return Type::KnownInstance(KnownInstanceType::Annotated(TypeInContext::new(
                     self.db(),
                     ty,
+                    self.typevar_binding_context,
                 )));
             }
             Type::SpecialForm(SpecialFormType::Optional) => {
@@ -10959,6 +11020,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
 
                 match **slice {
                     ast::Expr::Tuple(ref tuple) => {
+                        let typevar_binding_context = self.typevar_binding_context;
                         let mut elements = tuple
                             .elts
                             .iter()
@@ -10971,6 +11033,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                                 db,
                                 None,
                                 Ok(UnionType::from_elements(db, elements)),
+                                typevar_binding_context,
                             ),
                         ));
 
@@ -10995,7 +11058,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 // Similar to the branch above that handles `type[…]`, handle `typing.Type[…]`
                 let argument_ty = self.infer_type_expression(slice);
                 return Type::KnownInstance(KnownInstanceType::TypeGenericAlias(
-                    InternedType::new(self.db(), argument_ty),
+                    TypeInContext::new(self.db(), argument_ty, self.typevar_binding_context),
                 ));
             }
             Type::SpecialForm(SpecialFormType::Callable) => {
@@ -11004,7 +11067,9 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     .as_callable()
                     .expect("always returns Type::Callable");
 
-                return Type::KnownInstance(KnownInstanceType::Callable(callable));
+                return Type::KnownInstance(KnownInstanceType::Callable(
+                    CallableTypeInstance::new(self.db(), callable, self.typevar_binding_context),
+                ));
             }
             // `typing` special forms with a single generic argument
             Type::SpecialForm(
@@ -11095,8 +11160,32 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     .map(Type::from)
                     .unwrap_or_else(Type::unknown);
             }
-            Type::KnownInstance(KnownInstanceType::UnionType(_)) => {
-                return todo_type!("Specialization of union type alias");
+            Type::KnownInstance(KnownInstanceType::UnionType(instance)) => {
+                return self.infer_explicitly_specialized_type_alias(
+                    subscript,
+                    value_ty,
+                    instance.binding_context(self.db()),
+                    false,
+                );
+            }
+            Type::KnownInstance(
+                KnownInstanceType::Annotated(instance)
+                | KnownInstanceType::TypeGenericAlias(instance),
+            ) => {
+                return self.infer_explicitly_specialized_type_alias(
+                    subscript,
+                    value_ty,
+                    instance.binding_context(self.db()),
+                    false,
+                );
+            }
+            Type::KnownInstance(KnownInstanceType::Callable(instance)) => {
+                return self.infer_explicitly_specialized_type_alias(
+                    subscript,
+                    value_ty,
+                    instance.binding_context(self.db()),
+                    false,
+                );
             }
             _ => {}
         }

crates/ty_python_semantic/src/types/infer/builder/type_expression.rs

@@ -2,6 +2,8 @@ use itertools::Either;
 use ruff_python_ast as ast;
 
 use super::{DeferredExpressionState, TypeInferenceBuilder};
+use crate::FxOrderSet;
+use crate::semantic_index::definition::Definition;
 use crate::types::diagnostic::{
     self, INVALID_TYPE_FORM, NON_SUBSCRIPTABLE, report_invalid_argument_number_to_special_form,
     report_invalid_arguments_to_callable,
@@ -11,9 +13,10 @@ use crate::types::string_annotation::parse_string_annotation;
 use crate::types::tuple::{TupleSpecBuilder, TupleType};
 use crate::types::visitor::any_over_type;
 use crate::types::{
-    CallableType, DynamicType, IntersectionBuilder, KnownClass, KnownInstanceType,
-    LintDiagnosticGuard, Parameter, Parameters, SpecialFormType, SubclassOfType, Type,
-    TypeAliasType, TypeContext, TypeIsType, UnionBuilder, UnionType, todo_type,
+    BindingContext, CallableType, DynamicType, GenericContext, IntersectionBuilder, KnownClass,
+    KnownInstanceType, LintDiagnosticGuard, Parameter, Parameters, SpecialFormType, SubclassOfType,
+    Type, TypeAliasType, TypeContext, TypeInContext, TypeIsType, TypeMapping, UnionBuilder,
+    UnionType, todo_type,
 };
 
 /// Type expressions
@@ -679,11 +682,13 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                 }
                 Type::unknown()
             }
-            ast::Expr::Subscript(ast::ExprSubscript {
-                value,
-                slice: parameters,
-                ..
-            }) => {
+            ast::Expr::Subscript(
+                subscript @ ast::ExprSubscript {
+                    value,
+                    slice: parameters,
+                    ..
+                },
+            ) => {
                 let parameters_ty = match self.infer_expression(value, TypeContext::default()) {
                     Type::SpecialForm(SpecialFormType::Union) => match &**parameters {
                         ast::Expr::Tuple(tuple) => {
@@ -698,6 +703,40 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                         }
                         _ => self.infer_subclass_of_type_expression(parameters),
                     },
+                    value_ty @ Type::ClassLiteral(class_literal) => {
+                        if class_literal.is_protocol(self.db()) {
+                            SubclassOfType::from(
+                                self.db(),
+                                todo_type!("type[T] for protocols").expect_dynamic(),
+                            )
+                        } else {
+                            match class_literal.generic_context(self.db()) {
+                                Some(generic_context) => {
+                                    let db = self.db();
+                                    let specialize = |types: &[Option<Type<'db>>]| {
+                                        SubclassOfType::from(
+                                            db,
+                                            class_literal.apply_specialization(db, |_| {
+                                                generic_context
+                                                    .specialize_partial(db, types.iter().copied())
+                                            }),
+                                        )
+                                    };
+                                    self.infer_explicit_callable_specialization(
+                                        subscript,
+                                        value_ty,
+                                        generic_context,
+                                        specialize,
+                                    )
+                                }
+                                None => {
+                                    // TODO: emit a diagnostic if you try to specialize a non-generic class.
+                                    self.infer_type_expression(parameters);
+                                    todo_type!("specialized non-generic class")
+                                }
+                            }
+                        }
+                    }
                     _ => {
                         self.infer_type_expression(parameters);
                         todo_type!("unsupported nested subscript in type[X]")
@@ -714,6 +753,84 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
         }
     }
 
+    /// Infer the type of an explicitly specialized generic type alias (implicit or PEP 613).
+    pub(crate) fn infer_explicitly_specialized_type_alias(
+        &mut self,
+        subscript: &ast::ExprSubscript,
+        mut value_ty: Type<'db>,
+        typevar_binding_context: Option<Definition<'db>>,
+        in_type_expression: bool,
+    ) -> Type<'db> {
+        let db = self.db();
+
+        let Some(typevar_binding_context) = typevar_binding_context else {
+            if let Some(builder) = self.context.report_lint(&INVALID_TYPE_FORM, subscript) {
+                let mut diag = builder.into_diagnostic(format_args!(
+                    "`{}` is not subscriptable",
+                    value_ty.display(db)
+                ));
+                diag.info("Consider creating a type alias to create a binding context for the type variable(s)");
+            }
+            return Type::unknown();
+        };
+
+        if let Type::KnownInstance(KnownInstanceType::TypeVar(typevar)) = value_ty
+            && let Some(definition) = typevar.definition(db)
+        {
+            value_ty = value_ty.apply_type_mapping(
+                db,
+                &TypeMapping::BindLegacyTypevars(BindingContext::Definition(definition)),
+                TypeContext::default(),
+            );
+        }
+
+        let mut variables = FxOrderSet::default();
+        value_ty.find_legacy_typevars(db, Some(typevar_binding_context), &mut variables);
+        let generic_context = GenericContext::from_typevar_instances(db, variables);
+
+        let scope_id = self.scope();
+        let current_typevar_binding_context = self.typevar_binding_context;
+        let specialize = |types: &[Option<Type<'db>>]| {
+            let specialized = value_ty.apply_specialization(
+                db,
+                generic_context.specialize_partial(db, types.iter().copied()),
+            );
+
+            if in_type_expression {
+                specialized
+                    .in_type_expression(db, scope_id, current_typevar_binding_context)
+                    .unwrap_or_else(|_| Type::unknown())
+            } else {
+                // Update the binding context
+                match specialized {
+                    // Type::GenericAlias(alias) => Type::GenericAlias(GenericAlias::new(
+                    //     db,
+                    //     alias.origin(db),
+                    //     alias.specialization(db),
+                    //     current_typevar_binding_context,
+                    // )),
+                    Type::KnownInstance(KnownInstanceType::TypeGenericAlias(instance)) => {
+                        Type::KnownInstance(KnownInstanceType::TypeGenericAlias(
+                            TypeInContext::new(
+                                db,
+                                instance.inner(db),
+                                current_typevar_binding_context,
+                            ),
+                        ))
+                    }
+                    _ => specialized,
+                }
+            }
+        };
+
+        self.infer_explicit_callable_specialization(
+            subscript,
+            value_ty,
+            generic_context,
+            specialize,
+        )
+    }
+
     fn infer_subscript_type_expression(
         &mut self,
         subscript: &ast::ExprSubscript,
@@ -804,10 +921,6 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                     }
                     Type::unknown()
                 }
-                KnownInstanceType::TypeVar(_) => {
-                    self.infer_type_expression(slice);
-                    todo_type!("TypeVar annotations")
-                }
                 KnownInstanceType::TypeAliasType(type_alias @ TypeAliasType::PEP695(_)) => {
                     match type_alias.generic_context(self.db()) {
                         Some(generic_context) => {
@@ -850,11 +963,7 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                     self.infer_type_expression(slice);
                     todo_type!("Generic stringified PEP-613 type alias")
                 }
-                KnownInstanceType::UnionType(_) => {
-                    self.infer_type_expression(slice);
-                    todo_type!("Generic specialization of types.UnionType")
-                }
-                KnownInstanceType::Literal(ty) | KnownInstanceType::TypeGenericAlias(ty) => {
+                KnownInstanceType::Literal(ty) => {
                     self.infer_type_expression(slice);
                     if let Some(builder) = self.context.report_lint(&INVALID_TYPE_FORM, subscript) {
                         builder.into_diagnostic(format_args!(
@@ -864,14 +973,36 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                     }
                     Type::unknown()
                 }
-                KnownInstanceType::Callable(_) => {
-                    self.infer_type_expression(slice);
-                    todo_type!("Generic specialization of typing.Callable")
-                }
-                KnownInstanceType::Annotated(_) => {
-                    self.infer_type_expression(slice);
-                    todo_type!("Generic specialization of typing.Annotated")
-                }
+                KnownInstanceType::TypeVar(instance) => self
+                    .infer_explicitly_specialized_type_alias(
+                        subscript,
+                        value_ty,
+                        instance.definition(self.db()),
+                        false,
+                    ),
+                KnownInstanceType::UnionType(instance) => self
+                    .infer_explicitly_specialized_type_alias(
+                        subscript,
+                        value_ty,
+                        instance.binding_context(self.db()),
+                        true,
+                    ),
+                KnownInstanceType::Annotated(instance)
+                | KnownInstanceType::TypeGenericAlias(instance)
+                | KnownInstanceType::GenericAlias(instance) => self
+                    .infer_explicitly_specialized_type_alias(
+                        subscript,
+                        value_ty,
+                        instance.binding_context(self.db()),
+                        true,
+                    ),
+                KnownInstanceType::Callable(instance) => self
+                    .infer_explicitly_specialized_type_alias(
+                        subscript,
+                        value_ty,
+                        instance.binding_context(self.db()),
+                        true,
+                    ),
                 KnownInstanceType::NewType(newtype) => {
                     self.infer_type_expression(&subscript.slice);
                     if let Some(builder) = self.context.report_lint(&INVALID_TYPE_FORM, subscript) {
@@ -912,13 +1043,9 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
                     }
                 }
             }
-            Type::GenericAlias(_) => {
-                self.infer_type_expression(slice);
-                // If the generic alias is already fully specialized, this is an error. But it
-                // could have been specialized with another typevar (e.g. a type alias like `MyList
-                // = list[T]`), in which case it's later valid to do `MyList[int]`.
-                todo_type!("specialized generic alias in type expression")
-            }
+            // Type::GenericAlias(alias) => {
+            //     self.infer_explicitly_specialized_type_alias(subscript, value_ty, None, true)
+            // }
             Type::StringLiteral(_) => {
                 self.infer_type_expression(slice);
                 // For stringified TypeAlias; remove once properly supported
@@ -927,6 +1054,7 @@ impl<'db> TypeInferenceBuilder<'db, '_> {
             _ => {
                 self.infer_type_expression(slice);
                 if let Some(builder) = self.context.report_lint(&INVALID_TYPE_FORM, subscript) {
+                    dbg!(&value_ty);
                     builder.into_diagnostic(format_args!(
                         "Invalid subscript of object of type `{}` in type expression",
                         value_ty.display(self.db())

crates/ty_python_semantic/src/types/liskov.rs

@@ -49,11 +49,6 @@ fn check_class_declaration<'db>(
         return;
     };
 
-    // TODO: classmethods and staticmethods
-    if function.is_classmethod(db) || function.is_staticmethod(db) {
-        return;
-    }
-
     // Constructor methods are not checked for Liskov compliance
     if matches!(
         &*member.name,

crates/ty_python_semantic/src/types/mro.rs

@@ -100,7 +100,13 @@ impl<'db> Mro<'db> {
             if original_bases.contains(&Type::SpecialForm(SpecialFormType::Protocol)) {
                 return;
             }
-            if remaining_bases.iter().any(Type::is_generic_alias) {
+            if remaining_bases.iter().any(|ty| {
+                matches!(
+                    ty,
+                    Type::GenericAlias(..)
+                        | Type::KnownInstance(KnownInstanceType::GenericAlias(_))
+                )
+            }) {
                 return;
             }
             resolved_bases.push(ClassBase::Generic);

crates/ty_python_semantic/src/types/protocol_class.rs

@@ -300,7 +300,7 @@ impl<'db> ProtocolInterface<'db> {
                     .and(db, || {
                         our_type.has_relation_to_impl(
                             db,
-                            Type::Callable(other_type.bind_self(db, None)),
+                            Type::Callable(protocol_bind_self(db, other_type, None)),
                             inferable,
                             relation,
                             relation_visitor,
@@ -313,7 +313,7 @@ impl<'db> ProtocolInterface<'db> {
                         ProtocolMemberKind::Method(other_method),
                     ) => our_method.bind_self(db, None).has_relation_to_impl(
                         db,
-                        other_method.bind_self(db, None),
+                        protocol_bind_self(db, other_method, None),
                         inferable,
                         relation,
                         relation_visitor,
@@ -712,7 +712,7 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
                             .map(|callable| callable.apply_self(db, fallback_other))
                             .has_relation_to_impl(
                                 db,
-                                method.bind_self(db, Some(fallback_other)),
+                                protocol_bind_self(db, *method, Some(fallback_other)),
                                 inferable,
                                 relation,
                                 relation_visitor,
@@ -912,3 +912,16 @@ fn proto_interface_cycle_initial<'db>(
 ) -> ProtocolInterface<'db> {
     ProtocolInterface::empty(db)
 }
+
+/// Bind `self`, and *also* discard the functionlike-ness of the callable.
+///
+/// This additional upcasting is required in order for protocols with `__call__` method
+/// members to be considered assignable to `Callable` types, since the `Callable` supertype
+/// of the `__call__` method will be function-like but a `Callable` type is not.
+fn protocol_bind_self<'db>(
+    db: &'db dyn Db,
+    callable: CallableType<'db>,
+    self_type: Option<Type<'db>>,
+) -> CallableType<'db> {
+    CallableType::new(db, callable.signatures(db).bind_self(db, self_type), false)
+}

crates/ty_server/src/server/api/requests/inlay_hints.rs

@@ -2,7 +2,8 @@ use std::borrow::Cow;
 
 use lsp_types::request::InlayHintRequest;
 use lsp_types::{InlayHintParams, Url};
-use ty_ide::{InlayHintKind, InlayHintLabel, inlay_hints};
+use ruff_db::files::File;
+use ty_ide::{InlayHintKind, InlayHintLabel, InlayHintTextEdit, inlay_hints};
 use ty_project::ProjectDatabase;
 
 use crate::PositionEncoding;
@@ -64,7 +65,14 @@ impl BackgroundDocumentRequestHandler for InlayHintRequestHandler {
                     padding_left: None,
                     padding_right: None,
                     data: None,
-                    text_edits: None,
+                    text_edits: Some(
+                        hint.text_edits
+                            .into_iter()
+                            .filter_map(|text_edit| {
+                                inlay_hint_text_edit(text_edit, db, file, snapshot.encoding())
+                            })
+                            .collect(),
+                    ),
                 })
             })
             .collect();
@@ -100,3 +108,26 @@ fn inlay_hint_label(
     }
     lsp_types::InlayHintLabel::LabelParts(label_parts)
 }
+
+fn inlay_hint_text_edit(
+    inlay_hint_text_edit: InlayHintTextEdit,
+    db: &ProjectDatabase,
+    file: File,
+    encoding: PositionEncoding,
+) -> Option<lsp_types::TextEdit> {
+    Some(lsp_types::TextEdit {
+        range: lsp_types::Range {
+            start: inlay_hint_text_edit
+                .range
+                .start()
+                .to_lsp_position(db, file, encoding)?
+                .local_position(),
+            end: inlay_hint_text_edit
+                .range
+                .end()
+                .to_lsp_position(db, file, encoding)?
+                .local_position(),
+        },
+        new_text: inlay_hint_text_edit.new_text,
+    })
+}

crates/ty_server/tests/e2e/inlay_hints.rs

@@ -63,7 +63,22 @@ y = foo(1)
             }
           }
         ],
-        "kind": 1
+        "kind": 1,
+        "textEdits": [
+          {
+            "range": {
+              "start": {
+                "line": 5,
+                "character": 1
+              },
+              "end": {
+                "line": 5,
+                "character": 1
+              }
+            },
+            "newText": ": int"
+          }
+        ]
       },
       {
         "position": {
@@ -91,7 +106,8 @@ y = foo(1)
             "value": "="
           }
         ],
-        "kind": 2
+        "kind": 2,
+        "textEdits": []
       }
     ]
     "#);

playground/ty/src/Playground.tsx

@@ -501,7 +501,7 @@ export interface InitializedPlayground {
 
 // Run once during startup. Initializes monaco, loads the wasm file, and restores the previous editor state.
 async function startPlayground(): Promise<InitializedPlayground> {
-  const ty = await import("../ty_wasm");
+  const ty = await import("ty_wasm");
   await ty.default();
   const version = ty.version();
   const monaco = await loader.init();

playground/ty/vite.config.ts

@@ -3,6 +3,7 @@ import tailwindcss from "@tailwindcss/vite";
 import react from "@vitejs/plugin-react-swc";
 import { dirname, join } from "path";
 import { fileURLToPath } from "url";
+import { normalizePath } from "vite";
 import { viteStaticCopy } from "vite-plugin-static-copy";
 
 const PYODIDE_EXCLUDE = [
@@ -15,15 +16,17 @@ const PYODIDE_EXCLUDE = [
 // https://vitejs.dev/config/
 export default defineConfig({
   plugins: [react(), tailwindcss(), viteStaticCopyPyodide()],
-  optimizeDeps: { exclude: ["pyodide"] },
+  optimizeDeps: { exclude: ["pyodide", "ty_wasm"] },
 });
 
 export function viteStaticCopyPyodide() {
-  const pyodideDir = dirname(fileURLToPath(import.meta.resolve("pyodide")));
+  const pyodideDir = normalizePath(
+    join(dirname(fileURLToPath(import.meta.resolve("pyodide"))), "*"),
+  );
   return viteStaticCopy({
     targets: [
       {
-        src: [join(pyodideDir, "*"), ...PYODIDE_EXCLUDE],
+        src: [pyodideDir, ...PYODIDE_EXCLUDE],
         dest: "assets",
       },
     ],

scripts/add_rule.py

@@ -14,6 +14,7 @@ from __future__ import annotations
 
 import argparse
 import subprocess
+from pathlib import Path
 
 from _utils import ROOT_DIR, dir_name, get_indent, pascal_case, snake_case
 
@@ -153,7 +154,7 @@ pub(crate) fn {rule_name_snake}(checker: &mut Checker) {{}}
     _rustfmt(rules_mod)
 
 
-def _rustfmt(path: str) -> None:
+def _rustfmt(path: str | Path) -> None:
     subprocess.run(["rustfmt", path])
 
 

scripts/check_ecosystem.py

@@ -22,10 +22,11 @@ import re
 import tempfile
 import time
 from asyncio.subprocess import PIPE, create_subprocess_exec
+from collections.abc import Awaitable
 from contextlib import asynccontextmanager, nullcontext
 from pathlib import Path
 from signal import SIGINT, SIGTERM
-from typing import TYPE_CHECKING, NamedTuple, Self, TypeVar
+from typing import TYPE_CHECKING, Any, NamedTuple, Self, TypeVar
 
 if TYPE_CHECKING:
     from collections.abc import AsyncIterator, Iterator, Sequence
@@ -342,7 +343,7 @@ DIFF_LINE_RE = re.compile(
     r"^(?P<pre>[+-]) (?P<inner>(?P<path>[^:]+):(?P<lnum>\d+):\d+:) (?P<post>.*)$",
 )
 
-T = TypeVar("T")
+T = TypeVar("T", bound=Awaitable[Any])
 
 
 async def main(

scripts/pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "scripts"
 version = "0.0.1"
-dependencies = ["stdlibs"]
+dependencies = ["stdlibs", "tqdm", "mdformat", "pyyaml"]
 requires-python = ">=3.12"
 
 [tool.black]
@@ -9,3 +9,11 @@ line-length = 88
 
 [tool.ruff]
 extend = "../pyproject.toml"
+
+[tool.ty.src]
+# `ty_benchmark` is a standalone project with its own pyproject.toml files, search paths, etc.
+exclude = ["./ty_benchmark"]
+
+[tool.ty.rules]
+possibly-unresolved-reference = "error"
+division-by-zero = "error"

scripts/ty_benchmark/pyproject.toml

@@ -19,3 +19,7 @@ packages = ["src/benchmark"]
 ignore = [
     "E501", # We use ruff format
 ]
+
+[tool.ty.rules]
+possibly-unresolved-reference = "error"
+division-by-zero = "error"

scripts/update_ambiguous_characters.py

@@ -43,7 +43,7 @@ def format_number(number: int) -> str:
     # underscore-delimited in the generated file, so we now preserve that property to
     # avoid unnecessary churn.
     if number > 100000:
-        number = str(number)
+        number: str = str(number)
         number = "_".join(number[i : i + 3] for i in range(0, len(number), 3))
         return f"{number}_u32"