prune impossible paths during BDD construction

Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>

crates/ty/docs/rules.md

@@ -8,7 +8,7 @@
 Default level: <a href="../../rules#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#L542" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L543" target="_blank">View source</a>
 </small>
 
 
@@ -80,7 +80,7 @@ def test(): -> "int":
 Default level: <a href="../../rules#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#L141" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L142" target="_blank">View source</a>
 </small>
 
 
@@ -104,7 +104,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
 Default level: <a href="../../rules#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/0.0.7">0.0.7</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-top-callable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L159" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L160" target="_blank">View source</a>
 </small>
 
 
@@ -135,7 +135,7 @@ def f(x: object):
 Default level: <a href="../../rules#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#L210" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L211" target="_blank">View source</a>
 </small>
 
 
@@ -167,7 +167,7 @@ f(int)  # error
 Default level: <a href="../../rules#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#L236" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L237" target="_blank">View source</a>
 </small>
 
 
@@ -198,7 +198,7 @@ a = 1
 Default level: <a href="../../rules#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#L261" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L262" target="_blank">View source</a>
 </small>
 
 
@@ -230,7 +230,7 @@ class C(A, B): ...
 Default level: <a href="../../rules#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#L287" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L288" target="_blank">View source</a>
 </small>
 
 
@@ -262,7 +262,7 @@ class B(A): ...
 Default level: <a href="../../rules#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%20cyclic-type-alias-definition" target="_blank">Related issues</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>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L314" target="_blank">View source</a>
 </small>
 
 
@@ -290,7 +290,7 @@ type B = A
 Default level: <a href="../../rules#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#L357" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L358" target="_blank">View source</a>
 </small>
 
 
@@ -317,7 +317,7 @@ old_func()  # emits [deprecated] diagnostic
 Default level: <a href="../../rules#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#L335" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L336" target="_blank">View source</a>
 </small>
 
 
@@ -346,7 +346,7 @@ false positives it can produce.
 Default level: <a href="../../rules#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#L378" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L379" target="_blank">View source</a>
 </small>
 
 
@@ -373,7 +373,7 @@ class B(A, A): ...
 Default level: <a href="../../rules#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#L399" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L400" target="_blank">View source</a>
 </small>
 
 
@@ -529,7 +529,7 @@ def test(): -> "Literal[5]":
 Default level: <a href="../../rules#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#L625" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L626" target="_blank">View source</a>
 </small>
 
 
@@ -559,7 +559,7 @@ class C(A, B): ...
 Default level: <a href="../../rules#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#L649" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L650" target="_blank">View source</a>
 </small>
 
 
@@ -579,13 +579,47 @@ t = (0, 1, 2)
 t[3]  # IndexError: tuple index out of range
 ```
 
+## `ineffective-final`
+
+<small>
+Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
+Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.33">0.0.1-alpha.33</a>) ·
+<a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20ineffective-final" target="_blank">Related issues</a> ·
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1793" target="_blank">View source</a>
+</small>
+
+
+**What it does**
+
+Checks for calls to `final()` that type checkers cannot interpret.
+
+**Why is this bad?**
+
+The `final()` function is designed to be used as a decorator. When called directly
+as a function (e.g., `final(type(...))`), type checkers will not understand the
+application of `final` and will not prevent subclassing.
+
+**Example**
+
+
+```python
+from typing import final
+
+# Incorrect: type checkers will not prevent subclassing
+MyClass = final(type("MyClass", (), {}))
+
+# Correct: use `final` as a decorator
+@final
+class MyClass: ...
+```
+
 ## `instance-layout-conflict`
 
 <small>
 Default level: <a href="../../rules#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#L431" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L432" target="_blank">View source</a>
 </small>
 
 
@@ -674,7 +708,7 @@ an atypical memory layout.
 Default level: <a href="../../rules#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#L703" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L704" target="_blank">View source</a>
 </small>
 
 
@@ -701,7 +735,7 @@ func("foo")  # error: [invalid-argument-type]
 Default level: <a href="../../rules#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#L743" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L744" target="_blank">View source</a>
 </small>
 
 
@@ -729,7 +763,7 @@ a: int = ''
 Default level: <a href="../../rules#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#L2122" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2151" target="_blank">View source</a>
 </small>
 
 
@@ -763,7 +797,7 @@ C.instance_var = 3  # error: Cannot assign to instance variable
 Default level: <a href="../../rules#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#L765" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L766" target="_blank">View source</a>
 </small>
 
 
@@ -799,7 +833,7 @@ asyncio.run(main())
 Default level: <a href="../../rules#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#L795" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L796" target="_blank">View source</a>
 </small>
 
 
@@ -823,7 +857,7 @@ class A(42): ...  # error: [invalid-base]
 Default level: <a href="../../rules#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#L880" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L881" target="_blank">View source</a>
 </small>
 
 
@@ -850,7 +884,7 @@ with 1:
 Default level: <a href="../../rules#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#L901" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L902" target="_blank">View source</a>
 </small>
 
 
@@ -879,7 +913,7 @@ a: str
 Default level: <a href="../../rules#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#L924" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L925" target="_blank">View source</a>
 </small>
 
 
@@ -923,7 +957,7 @@ except ZeroDivisionError:
 Default level: <a href="../../rules#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.28">0.0.1-alpha.28</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-explicit-override" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1792" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1821" target="_blank">View source</a>
 </small>
 
 
@@ -965,7 +999,7 @@ class D(A):
 Default level: <a href="../../rules#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.35">0.0.1-alpha.35</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-frozen-dataclass-subclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2373" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2402" target="_blank">View source</a>
 </small>
 
 
@@ -1009,7 +1043,7 @@ class NonFrozenChild(FrozenBase):  # Error raised here
 Default level: <a href="../../rules#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#L1002" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1003" target="_blank">View source</a>
 </small>
 
 
@@ -1047,7 +1081,7 @@ class D(Generic[U, T]): ...
 Default level: <a href="../../rules#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/0.0.12">0.0.12</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-generic-enum" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L960" target="_blank">View source</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>
 </small>
 
 
@@ -1126,7 +1160,7 @@ a = 20 / 0  # type: ignore
 Default level: <a href="../../rules#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#L670" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L671" target="_blank">View source</a>
 </small>
 
 
@@ -1165,7 +1199,7 @@ carol = Person(name="Carol", age=25)  # typo!
 Default level: <a href="../../rules#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#L1033" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1034" target="_blank">View source</a>
 </small>
 
 
@@ -1200,7 +1234,7 @@ def f(t: TypeVar("U")): ...
 Default level: <a href="../../rules#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#L1130" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1131" target="_blank">View source</a>
 </small>
 
 
@@ -1234,7 +1268,7 @@ class B(metaclass=f): ...
 Default level: <a href="../../rules#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#L2275" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2304" target="_blank">View source</a>
 </small>
 
 
@@ -1341,7 +1375,7 @@ Correct use of `@override` is enforced by ty's `invalid-explicit-override` rule.
 Default level: <a href="../../rules#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#L577" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L578" target="_blank">View source</a>
 </small>
 
 
@@ -1395,7 +1429,7 @@ AttributeError: Cannot overwrite NamedTuple attribute _asdict
 Default level: <a href="../../rules#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#L1106" target="_blank">View source</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>
 </small>
 
 
@@ -1425,7 +1459,7 @@ Baz = NewType("Baz", int | str)  # error: invalid base for `typing.NewType`
 Default level: <a href="../../rules#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#L1157" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1158" target="_blank">View source</a>
 </small>
 
 
@@ -1475,7 +1509,7 @@ def foo(x: int) -> int: ...
 Default level: <a href="../../rules#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#L1256" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1257" target="_blank">View source</a>
 </small>
 
 
@@ -1501,7 +1535,7 @@ def f(a: int = ''): ...
 Default level: <a href="../../rules#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#L1061" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1062" target="_blank">View source</a>
 </small>
 
 
@@ -1532,7 +1566,7 @@ P2 = ParamSpec("S2")  # error: ParamSpec name must match the variable it's assig
 Default level: <a href="../../rules#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#L513" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L514" target="_blank">View source</a>
 </small>
 
 
@@ -1566,7 +1600,7 @@ TypeError: Protocols can only inherit from other protocols, got <class 'int'>
 Default level: <a href="../../rules#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#L1276" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1277" target="_blank">View source</a>
 </small>
 
 
@@ -1615,7 +1649,7 @@ def g():
 Default level: <a href="../../rules#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#L724" target="_blank">View source</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>
 </small>
 
 
@@ -1640,7 +1674,7 @@ def func() -> int:
 Default level: <a href="../../rules#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#L1319" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1320" target="_blank">View source</a>
 </small>
 
 
@@ -1736,7 +1770,7 @@ class C: ...
 Default level: <a href="../../rules#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/0.0.10">0.0.10</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-total-ordering" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2411" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2440" target="_blank">View source</a>
 </small>
 
 
@@ -1782,7 +1816,7 @@ class MyClass:
 Default level: <a href="../../rules#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#L1085" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1086" target="_blank">View source</a>
 </small>
 
 
@@ -1809,7 +1843,7 @@ NewAlias = TypeAliasType(get_name(), int)        # error: TypeAliasType name mus
 Default level: <a href="../../rules#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.29">0.0.1-alpha.29</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1551" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1552" target="_blank">View source</a>
 </small>
 
 
@@ -1856,7 +1890,7 @@ Bar[int]  # error: too few arguments
 Default level: <a href="../../rules#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#L1358" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1359" target="_blank">View source</a>
 </small>
 
 
@@ -1886,7 +1920,7 @@ TYPE_CHECKING = ''
 Default level: <a href="../../rules#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#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>
 
 
@@ -1916,7 +1950,7 @@ b: Annotated[int]  # `Annotated` expects at least two arguments
 Default level: <a href="../../rules#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#L1434" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1435" target="_blank">View source</a>
 </small>
 
 
@@ -1950,7 +1984,7 @@ f(10)  # Error
 Default level: <a href="../../rules#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#L1406" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1407" target="_blank">View source</a>
 </small>
 
 
@@ -1984,7 +2018,7 @@ class C:
 Default level: <a href="../../rules#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#L1462" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1463" target="_blank">View source</a>
 </small>
 
 
@@ -2019,7 +2053,7 @@ T = TypeVar('T', bound=str)  # valid bound TypeVar
 Default level: <a href="../../rules#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/0.0.9">0.0.9</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-typed-dict-statement" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2250" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2279" target="_blank">View source</a>
 </small>
 
 
@@ -2050,7 +2084,7 @@ class Foo(TypedDict):
 Default level: <a href="../../rules#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#L1491" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1492" target="_blank">View source</a>
 </small>
 
 
@@ -2075,7 +2109,7 @@ func()  # TypeError: func() missing 1 required positional argument: 'x'
 Default level: <a href="../../rules#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#L2223" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2252" target="_blank">View source</a>
 </small>
 
 
@@ -2108,7 +2142,7 @@ alice["age"]  # KeyError
 Default level: <a href="../../rules#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#L1510" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1511" target="_blank">View source</a>
 </small>
 
 
@@ -2137,7 +2171,7 @@ func("string")  # error: [no-matching-overload]
 Default level: <a href="../../rules#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#L1592" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1593" target="_blank">View source</a>
 </small>
 
 
@@ -2163,7 +2197,7 @@ for i in 34:  # TypeError: 'int' object is not iterable
 Default level: <a href="../../rules#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-subscriptable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1533" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1534" target="_blank">View source</a>
 </small>
 
 
@@ -2187,7 +2221,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
 Default level: <a href="../../rules#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.29">0.0.1-alpha.29</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20override-of-final-method" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1765" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1766" target="_blank">View source</a>
 </small>
 
 
@@ -2220,7 +2254,7 @@ class B(A):
 Default level: <a href="../../rules#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#L1643" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1644" target="_blank">View source</a>
 </small>
 
 
@@ -2247,7 +2281,7 @@ f(1, x=2)  # Error raised here
 Default level: <a href="../../rules#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#L1976" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2005" target="_blank">View source</a>
 </small>
 
 
@@ -2274,7 +2308,7 @@ f(x=1)  # Error raised here
 Default level: <a href="../../rules#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#L1664" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1665" target="_blank">View source</a>
 </small>
 
 
@@ -2302,7 +2336,7 @@ A.c  # AttributeError: type object 'A' has no attribute 'c'
 Default level: <a href="../../rules#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#L184" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L185" target="_blank">View source</a>
 </small>
 
 
@@ -2334,7 +2368,7 @@ A()[0]  # TypeError: 'A' object is not subscriptable
 Default level: <a href="../../rules#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.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#L1686" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1687" target="_blank">View source</a>
 </small>
 
 
@@ -2371,7 +2405,7 @@ from module import a  # ImportError: cannot import name 'a' from 'module'
 Default level: <a href="../../rules#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#L1716" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1717" target="_blank">View source</a>
 </small>
 
 
@@ -2435,7 +2469,7 @@ def test(): -> "int":
 Default level: <a href="../../rules#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#L2150" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2179" target="_blank">View source</a>
 </small>
 
 
@@ -2462,7 +2496,7 @@ cast(int, f())  # Redundant
 Default level: <a href="../../rules#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#L2098" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2127" target="_blank">View source</a>
 </small>
 
 
@@ -2492,7 +2526,7 @@ static_assert(int(2.0 * 3.0) == 6)  # error: does not have a statically known tr
 Default level: <a href="../../rules#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#L1742" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1743" target="_blank">View source</a>
 </small>
 
 
@@ -2521,7 +2555,7 @@ class B(A): ...  # Error raised here
 Default level: <a href="../../rules#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/0.0.1-alpha.30">0.0.1-alpha.30</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20super-call-in-named-tuple-method" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1910" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1939" target="_blank">View source</a>
 </small>
 
 
@@ -2555,7 +2589,7 @@ class F(NamedTuple):
 Default level: <a href="../../rules#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#L1850" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1879" target="_blank">View source</a>
 </small>
 
 
@@ -2582,7 +2616,7 @@ f("foo")  # Error raised here
 Default level: <a href="../../rules#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#L1828" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1857" target="_blank">View source</a>
 </small>
 
 
@@ -2610,7 +2644,7 @@ def _(x: int):
 Default level: <a href="../../rules#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#L1871" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1900" target="_blank">View source</a>
 </small>
 
 
@@ -2656,7 +2690,7 @@ class A:
 Default level: <a href="../../rules#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#L1937" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1966" target="_blank">View source</a>
 </small>
 
 
@@ -2680,7 +2714,7 @@ reveal_type(1)  # NameError: name 'reveal_type' is not defined
 Default level: <a href="../../rules#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#L1955" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1984" target="_blank">View source</a>
 </small>
 
 
@@ -2707,7 +2741,7 @@ f(x=1, y=2)  # Error raised here
 Default level: <a href="../../rules#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#L1997" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2026" target="_blank">View source</a>
 </small>
 
 
@@ -2735,7 +2769,7 @@ A().foo  # AttributeError: 'A' object has no attribute 'foo'
 Default level: <a href="../../rules#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#L2171" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2200" target="_blank">View source</a>
 </small>
 
 
@@ -2793,7 +2827,7 @@ def g():
 Default level: <a href="../../rules#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#L2019" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2048" target="_blank">View source</a>
 </small>
 
 
@@ -2818,7 +2852,7 @@ import foo  # ModuleNotFoundError: No module named 'foo'
 Default level: <a href="../../rules#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#L2038" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2067" target="_blank">View source</a>
 </small>
 
 
@@ -2843,7 +2877,7 @@ print(x)  # NameError: name 'x' is not defined
 Default level: <a href="../../rules#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#L813" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L814" target="_blank">View source</a>
 </small>
 
 
@@ -2882,7 +2916,7 @@ class D(C): ...  # error: [unsupported-base]
 Default level: <a href="../../rules#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#L1612" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1613" target="_blank">View source</a>
 </small>
 
 
@@ -2919,7 +2953,7 @@ b1 < b2 < b1  # exception raised here
 Default level: <a href="../../rules#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/1.0.0">1.0.0</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-dynamic-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L846" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L847" target="_blank">View source</a>
 </small>
 
 
@@ -2960,7 +2994,7 @@ def factory(base: type[Base]) -> type:
 Default level: <a href="../../rules#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#L2057" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2086" target="_blank">View source</a>
 </small>
 
 
@@ -3024,7 +3058,7 @@ to `false` to prevent this rule from reporting unused `type: ignore` comments.
 Default level: <a href="../../rules#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#L1200" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1201" target="_blank">View source</a>
 </small>
 
 
@@ -3087,7 +3121,7 @@ def foo(x: int | str) -> int | str:
 Default level: <a href="../../rules#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#L2079" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2108" target="_blank">View source</a>
 </small>
 
 

crates/ty_ide/src/completion.rs

@@ -2585,7 +2585,7 @@ type<CURSOR>
 
         assert_snapshot!(
             test.type_signatures().skip_auto_import().build().snapshot(),
-            @r"
+            @"
         type :: <class 'type'>
         TypeError :: <class 'TypeError'>
         ",
@@ -8009,7 +8009,7 @@ my_list[0].remove<CURSOR>
         );
         assert_snapshot!(
             builder.build().snapshot(),
-            @r"
+            @"
         removeprefix
         removesuffix
         ",
@@ -8030,7 +8030,7 @@ def f(x: Any | str):
         );
         assert_snapshot!(
             builder.build().snapshot(),
-            @r"
+            @"
         removeprefix
         removesuffix
         ",
@@ -8052,7 +8052,7 @@ def f(x: Intersection[int, Any] | str):
         );
         assert_snapshot!(
             builder.build().snapshot(),
-            @r"
+            @"
         removeprefix
         removesuffix
         ",

crates/ty_ide/src/docstring.rs

@@ -9,6 +9,7 @@
 use regex::Regex;
 use ruff_python_trivia::{PythonWhitespace, leading_indentation};
 use ruff_source_file::UniversalNewlines;
+use std::borrow::Cow;
 use std::collections::HashMap;
 use std::sync::LazyLock;
 
@@ -349,16 +350,37 @@ fn render_markdown(docstring: &str) -> String {
                     | "versionchanged" | "version-changed" | "version-deprecated" | "deprecated"
                     | "version-removed" | "versionremoved",
                 ) => {
+                    // Map version directives to human-readable phrases (matching Sphinx output)
+                    let pretty_directive = match directive.unwrap() {
+                        "versionadded" | "version-added" => Cow::Borrowed("Added in version"),
+                        "versionchanged" | "version-changed" => Cow::Borrowed("Changed in version"),
+                        "deprecated" | "version-deprecated" => {
+                            Cow::Borrowed("Deprecated since version")
+                        }
+                        "versionremoved" | "version-removed" => Cow::Borrowed("Removed in version"),
+                        other => Cow::Owned(
+                            other
+                                .char_indices()
+                                .map(|(index, c)| {
+                                    if index == 0 {
+                                        c.to_ascii_uppercase()
+                                    } else {
+                                        c
+                                    }
+                                })
+                                .collect(),
+                        ),
+                    };
+
                     // Render the argument of things like `.. version-added:: 4.0`
                     let suffix = if let Some(lang) = lang {
-                        format!(" *{lang}*")
+                        format!(" {lang}")
                     } else {
                         String::new()
                     };
                     // We prepend without_directive here out of caution for preserving input.
                     // This is probably gibberish/invalid syntax? But it's a no-op in normal cases.
-                    temp_owned_line =
-                        format!("**{without_directive}{}:**{suffix}", directive.unwrap());
+                    temp_owned_line = format!("**{without_directive}{pretty_directive}{suffix}:**");
 
                     line = temp_owned_line.as_str();
                     None
@@ -1076,7 +1098,7 @@ mod tests {
         assert_snapshot!(docstring.render_markdown(), @r#"
         The thing you need to understand is that computers are hard.  
           
-        **warning:**  
+        **Warning:**  
             Now listen here buckaroo you might have seen me say computers are hard,  
             and though "yeah I know computers are hard but NO you DON'T KNOW.  
           
@@ -1115,12 +1137,12 @@ mod tests {
         assert_snapshot!(docstring.render_markdown(), @"
         Some much-updated docs  
           
-        **version-added:** *3.0*  
+        **Added in version 3.0:**  
            Function added  
           
-        **version-changed:** *4.0*  
+        **Changed in version 4.0:**  
            The `spam` argument was added  
-        **version-changed:** *4.1*  
+        **Changed in version 4.1:**  
            The `spam` argument is considered evil now.  
           
            You really shouldnt use it  
@@ -1141,7 +1163,7 @@ mod tests {
         let docstring = Docstring::new(docstring.to_owned());
 
         assert_snapshot!(docstring.render_markdown(), @"
-        **wow this is some changes deprecated:** *1.2.3*  
+        **wow this is some changes Deprecated since version 1.2.3:**  
             x = 2
         ");
     }
@@ -1151,7 +1173,7 @@ mod tests {
     fn explicit_markdown_block_with_ps1_contents() {
         let docstring = r#"
         My cool func:
-        
+
         ```python
         >>> thing.do_thing()
         wow it did the thing
@@ -1162,7 +1184,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ```python
@@ -1179,7 +1201,7 @@ mod tests {
     fn explicit_markdown_block_with_underscore_contents_tick() {
         let docstring = r#"
         My cool func:
-        
+
         `````python
         x_y = thing_do();
         ``` # this should't close the fence!
@@ -1189,7 +1211,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         `````python
@@ -1205,7 +1227,7 @@ mod tests {
     fn explicit_markdown_block_with_underscore_contents_tilde() {
         let docstring = r#"
         My cool func:
-        
+
         ~~~~~python
         x_y = thing_do();
         ~~~ # this should't close the fence!
@@ -1215,7 +1237,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ~~~~~python
@@ -1233,7 +1255,7 @@ mod tests {
     fn explicit_markdown_block_with_indent_tick() {
         let docstring = r#"
         My cool func...
-        
+
         Returns:
             Some details
             `````python
@@ -1246,7 +1268,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func...  
           
         Returns:  
@@ -1267,7 +1289,7 @@ mod tests {
     fn explicit_markdown_block_with_indent_tilde() {
         let docstring = r#"
         My cool func...
-        
+
         Returns:
             Some details
             ~~~~~~python
@@ -1280,7 +1302,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func...  
           
         Returns:  
@@ -1299,14 +1321,14 @@ mod tests {
     fn explicit_markdown_block_with_unclosed_fence_tick() {
         let docstring = r#"
         My cool func:
-        
+
         ````python
         x_y = thing_do();
         "#;
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ````python
@@ -1320,14 +1342,14 @@ mod tests {
     fn explicit_markdown_block_with_unclosed_fence_tilde() {
         let docstring = r#"
         My cool func:
-        
+
         ~~~~~python
         x_y = thing_do();
         "#;
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ~~~~~python
@@ -1342,7 +1364,7 @@ mod tests {
     fn explicit_markdown_block_messy_corners_tick() {
         let docstring = r#"
         My cool func:
-        
+
                 ``````we still think this is a codefence```
             x_y = thing_do();
         ```````````` and are sloppy as heck with indentation and closing shrugggg
@@ -1350,7 +1372,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ``````we still think this is a codefence```
@@ -1365,7 +1387,7 @@ mod tests {
     fn explicit_markdown_block_messy_corners_tilde() {
         let docstring = r#"
         My cool func:
-        
+
                 ~~~~~~we still think this is a codefence~~~
             x_y = thing_do();
         ~~~~~~~~~~~~~ and are sloppy as heck with indentation and closing shrugggg
@@ -1373,7 +1395,7 @@ mod tests {
 
         let docstring = Docstring::new(docstring.to_owned());
 
-        assert_snapshot!(docstring.render_markdown(), @r"
+        assert_snapshot!(docstring.render_markdown(), @"
         My cool func:  
           
         ~~~~~~we still think this is a codefence~~~

crates/ty_ide/src/goto_definition.rs

@@ -1649,6 +1649,65 @@ Traceb<CURSOR>ackType
         assert_snapshot!(test.goto_definition(), @"No goto target found");
     }
 
+    /// goto-definition on a dynamic class literal (created via `type()`)
+    #[test]
+    fn goto_definition_dynamic_class_literal() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                r#"
+DynClass = type("DynClass", (), {})
+
+x = DynCla<CURSOR>ss()
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @r#"
+        info[goto-definition]: Go to definition
+         --> main.py:4:5
+          |
+        2 | DynClass = type("DynClass", (), {})
+        3 |
+        4 | x = DynClass()
+          |     ^^^^^^^^ Clicking here
+          |
+        info: Found 2 definitions
+           --> main.py:2:1
+            |
+          2 | DynClass = type("DynClass", (), {})
+            | --------
+          3 |
+          4 | x = DynClass()
+            |
+           ::: stdlib/builtins.pyi:137:9
+            |
+        135 |     def __class__(self, type: type[Self], /) -> None: ...
+        136 |     def __init__(self) -> None: ...
+        137 |     def __new__(cls) -> Self: ...
+            |         -------
+        138 |     # N.B. `object.__setattr__` and `object.__delattr__` are heavily special-cased by type checkers.
+        139 |     # Overriding them in subclasses has different semantics, even if the override has an identical signature.
+            |
+        "#);
+    }
+
+    /// goto-definition on a dangling dynamic class literal (not assigned to a variable)
+    #[test]
+    fn goto_definition_dangling_dynamic_class_literal() {
+        let test = CursorTest::builder()
+            .source(
+                "main.py",
+                r#"
+class Foo(type("Ba<CURSOR>r", (), {})):
+    pass
+"#,
+            )
+            .build();
+
+        assert_snapshot!(test.goto_definition(), @"No goto target found");
+    }
+
     // TODO: Should only list `a: int`
     #[test]
     fn redeclarations() {

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

@@ -20,16 +20,13 @@ class Base: ...
 class Mixin: ...
 
 # We synthesize a class type using the name argument
-Foo = type("Foo", (), {})
-reveal_type(Foo)  # revealed: <class 'Foo'>
+reveal_type(type("Foo", (), {}))  # revealed: <class 'Foo'>
 
 # With a single base class
-Foo2 = type("Foo", (Base,), {"attr": 1})
-reveal_type(Foo2)  # revealed: <class 'Foo'>
+reveal_type(type("Foo", (Base,), {"attr": 1}))  # revealed: <class 'Foo'>
 
 # With multiple base classes
-Foo3 = type("Foo", (Base, Mixin), {})
-reveal_type(Foo3)  # revealed: <class 'Foo'>
+reveal_type(type("Foo", (Base, Mixin), {}))  # revealed: <class 'Foo'>
 
 # The inferred type is assignable to type[Base] since Foo inherits from Base
 tests: list[type[Base]] = []
@@ -499,39 +496,38 @@ Other numbers of arguments are invalid:
 
 ```py
 # error: [no-matching-overload] "No overload of class `type` matches arguments"
-reveal_type(type("Foo", ()))  # revealed: Unknown
+reveal_type(type("Foo", ()))  # revealed: type[Unknown]
 
 # TODO: the keyword arguments for `Foo`/`Bar`/`Baz` here are invalid
-# (you cannot pass `metaclass=` to `type()`, and none of them have
-# base classes with `__init_subclass__` methods),
-# but `type[Unknown]` would be better than `Unknown` here
+# (none of them have base classes with `__init_subclass__` methods).
 #
+# The intent to create a new class is however clear,
+# so we still infer these as class-literal types.
+reveal_type(type("Foo", (), {}, weird_other_arg=42))  # revealed: <class 'Foo'>
+reveal_type(type("Bar", (int,), {}, weird_other_arg=42))  # revealed: <class 'Bar'>
+
+# You can't pass `metaclass=` to the `type()` constructor, but the intent is clear,
+# so we infer `<class 'Baz'>` here rather than `type[Unknown]`
 # error: [no-matching-overload] "No overload of class `type` matches arguments"
-reveal_type(type("Foo", (), {}, weird_other_arg=42))  # revealed: Unknown
-# error: [no-matching-overload] "No overload of class `type` matches arguments"
-reveal_type(type("Bar", (int,), {}, weird_other_arg=42))  # revealed: Unknown
-# error: [no-matching-overload] "No overload of class `type` matches arguments"
-reveal_type(type("Baz", (), {}, metaclass=type))  # revealed: Unknown
+reveal_type(type("Baz", (), {}, metaclass=type))  # revealed: <class 'Baz'>
 ```
 
-The following calls are also invalid, due to incorrect argument types.
-
-Inline calls (not assigned to a variable) fall back to regular `type` overload matching, which
-produces slightly different error messages than assigned dynamic class creation:
+The following calls are also invalid, due to incorrect argument types:
 
 ```py
 class Base: ...
 
-# error: 6 [invalid-argument-type] "Argument to class `type` is incorrect: Expected `str`, found `Literal[b"Foo"]`"
+# error: [invalid-argument-type] "Invalid argument to parameter 1 (`name`) of `type()`: Expected `str`, found `Literal[b"Foo"]`"
 type(b"Foo", (), {})
 
-# error: 13 [invalid-argument-type] "Argument to class `type` is incorrect: Expected `tuple[type, ...]`, found `<class 'Base'>`"
+# error: [invalid-argument-type] "Invalid argument to parameter 2 (`bases`) of `type()`: Expected `tuple[type, ...]`, found `<class 'Base'>`"
 type("Foo", Base, {})
 
-# error: 13 [invalid-argument-type] "Argument to class `type` is incorrect: Expected `tuple[type, ...]`, found `tuple[Literal[1], Literal[2]]`"
+# error: 14 [invalid-base] "Invalid class base with type `Literal[1]`"
+# error: 17 [invalid-base] "Invalid class base with type `Literal[2]`"
 type("Foo", (1, 2), {})
 
-# error: 22 [invalid-argument-type] "Argument to class `type` is incorrect: Expected `dict[str, Any]`, found `dict[str | bytes, Any]`"
+# error: [invalid-argument-type] "Invalid argument to parameter 3 (`namespace`) of `type()`: Expected `dict[str, Any]`, found `dict[Unknown | bytes, Unknown | int]`"
 type("Foo", (Base,), {b"attr": 1})
 ```
 
@@ -598,6 +594,19 @@ class Y(C, B): ...
 Conflict = type("Conflict", (X, Y), {})
 ```
 
+## MRO error highlighting (snapshot)
+
+<!-- snapshot-diagnostics -->
+
+This snapshot test documents the diagnostic highlighting range for dynamic class literals.
+Currently, the entire `type()` call expression is highlighted:
+
+```py
+class A: ...
+
+Dup = type("Dup", (A, A), {})  # error: [duplicate-base]
+```
+
 ## Metaclass conflicts
 
 Metaclass conflicts are detected and reported:
@@ -853,55 +862,77 @@ def f(*args, **kwargs):
 
     # Has a string first arg, but unknown additional args from *args
     B = type("B", *args, **kwargs)
-    # TODO: `type[Unknown]` would cause fewer false positives
-    reveal_type(B)  # revealed: <class 'str'>
+    reveal_type(B)  # revealed: type[Unknown]
 
     # Has string and tuple, but unknown additional args
     C = type("C", (), *args, **kwargs)
-    # TODO: `type[Unknown]` would cause fewer false positives
-    reveal_type(C)  # revealed: type
+    reveal_type(C)  # revealed: type[Unknown]
 
     # All three positional args provided, only **kwargs unknown
     D = type("D", (), {}, **kwargs)
-    # TODO: `type[Unknown]` would cause fewer false positives
-    reveal_type(D)  # revealed: type
+    reveal_type(D)  # revealed: <class 'D'>
 
     # Three starred expressions - we can't know how they expand
     a = ("E",)
     b = ((),)
     c = ({},)
     E = type(*a, *b, *c)
-    # TODO: `type[Unknown]` would cause fewer false positives
-    reveal_type(E)  # revealed: type
+    reveal_type(E)  # revealed: type[Unknown]
 ```
 
 ## Explicit type annotations
 
-TODO: Annotated assignments with `type()` calls don't currently synthesize the specific class type.
-This will be fixed when we support all `type()` calls (including inline) via generic handling.
+When an explicit type annotation is provided, the inferred type is checked against it:
 
 ```py
+# The annotation `type` is compatible with the inferred class literal type
+T: type = type("T", (), {})
+reveal_type(T)  # revealed: <class 'T'>
+
+# The annotation `type[Base]` is compatible with the inferred type
 class Base: ...
 
-# TODO: Should infer `<class 'T'>` instead of `type`
-T: type = type("T", (), {})
-reveal_type(T)  # revealed: type
-
-# TODO: Should infer `<class 'Derived'>` instead of `type[Base]}
-# error: [invalid-assignment] "Object of type `type` is not assignable to `type[Base]`"
 Derived: type[Base] = type("Derived", (Base,), {})
-reveal_type(Derived)  # revealed: type[Base]
+reveal_type(Derived)  # revealed: <class 'Derived'>
+
+# Incompatible annotation produces an error
+class Unrelated: ...
+
+# error: [invalid-assignment]
+Bad: type[Unrelated] = type("Bad", (Base,), {})
 ```
 
 ## Special base classes
 
 Some special base classes work with dynamic class creation, but special semantics may not be fully
-synthesized:
+synthesized.
+
+### Invalid special bases
+
+Dynamic classes cannot directly inherit from `Generic`, `Protocol`, or `TypedDict`. These special
+forms require class syntax for their semantics to be properly applied:
+
+```py
+from typing import Generic, Protocol, TypeVar
+from typing_extensions import TypedDict
+
+T = TypeVar("T")
+
+# error: [invalid-base] "Invalid base for class created via `type()`"
+GenericClass = type("GenericClass", (Generic[T],), {})
+
+# error: [unsupported-dynamic-base] "Unsupported base for class created via `type()`"
+ProtocolClass = type("ProtocolClass", (Protocol,), {})
+
+# error: [invalid-base] "Invalid base for class created via `type()`"
+TypedDictClass = type("TypedDictClass", (TypedDict,), {})
+```
 
 ### Protocol bases
 
+Inheriting from a class that is itself a protocol is valid:
+
 ```py
-# Protocol bases work - the class is created as a subclass of the protocol
 from typing import Protocol
 from ty_extensions import reveal_mro
 
@@ -918,8 +949,9 @@ reveal_type(instance)  # revealed: ProtoImpl
 
 ### TypedDict bases
 
+Inheriting from a class that is itself a TypedDict is valid:
+
 ```py
-# TypedDict bases work but TypedDict semantics aren't applied to dynamic subclasses
 from typing_extensions import TypedDict
 from ty_extensions import reveal_mro
 
@@ -952,26 +984,26 @@ reveal_mro(Point3D)  # revealed: (<class 'Point3D'>, <class 'Point'>, <class 'tu
 
 ### Enum bases
 
+Creating a class via `type()` that inherits from any Enum class fails at runtime because `EnumMeta`
+expects special attributes in the class dict that `type()` doesn't provide:
+
 ```py
-# Enum subclassing via type() is not supported - EnumMeta requires special dict handling
-# that type() cannot provide. This applies even to empty enums.
 from enum import Enum
 
 class Color(Enum):
     RED = 1
     GREEN = 2
 
+# Enums with members are final and cannot be subclassed
+# error: [subclass-of-final-class]
+ExtendedColor = type("ExtendedColor", (Color,), {})
+
 class EmptyEnum(Enum):
     pass
 
-# TODO: We should emit a diagnostic here - type() cannot create Enum subclasses
-ExtendedColor = type("ExtendedColor", (Color,), {})
-reveal_type(ExtendedColor)  # revealed: <class 'ExtendedColor'>
-
-# Even empty enums fail - EnumMeta requires special dict handling
-# TODO: We should emit a diagnostic here too
-ValidExtension = type("ValidExtension", (EmptyEnum,), {})
-reveal_type(ValidExtension)  # revealed: <class 'ValidExtension'>
+# Empty enums fail because EnumMeta requires special dict handling
+# error: [invalid-base] "Invalid base for class created via `type()`"
+InvalidExtension = type("InvalidExtension", (EmptyEnum,), {})
 ```
 
 ## `__init_subclass__` keyword arguments
@@ -992,9 +1024,6 @@ class Child(Base, required_arg="value"):
 # The dynamically assigned attribute has Unknown in its type
 reveal_type(Child.config)  # revealed: Unknown | str
 
-# Dynamic class creation - keyword arguments are not yet supported
-# TODO: This should work: type("DynamicChild", (Base,), {}, required_arg="value")
-# error: [no-matching-overload]
 DynamicChild = type("DynamicChild", (Base,), {}, required_arg="value")
 ```
 
@@ -1034,3 +1063,27 @@ reveal_type(Dynamic)  # revealed: <class 'Dynamic'>
 # Metaclass attributes are accessible on the class
 reveal_type(Dynamic.custom_attr)  # revealed: str
 ```
+
+## `final()` on dynamic classes
+
+Using `final()` as a function (not a decorator) on dynamic classes will not be understood by type
+checkers. The class is passed through unchanged, and subclassing will not be prevented:
+
+```py
+from typing import final
+
+# error: [ineffective-final]
+FinalClass = final(type("FinalClass", (), {}))
+reveal_type(FinalClass)  # revealed: <class 'FinalClass'>
+
+# Subclassing is allowed because type checkers don't understand `final()` called as a function
+class Child(FinalClass): ...
+
+# Same with base classes
+class Base: ...
+
+# error: [ineffective-final]
+FinalDerived = final(type("FinalDerived", (Base,), {}))
+
+class Child2(FinalDerived): ...
+```

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

@@ -0,0 +1,78 @@
+# Unsupported base for dynamic `type()` classes
+
+<!-- snapshot-diagnostics -->
+
+## `@final` class
+
+Classes decorated with `@final` cannot be subclassed:
+
+```py
+from typing import final
+
+@final
+class FinalClass:
+    pass
+
+X = type("X", (FinalClass,), {})  # error: [subclass-of-final-class]
+```
+
+## `Generic` base
+
+Dynamic classes created via `type()` cannot inherit from `Generic`:
+
+```py
+from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+X = type("X", (Generic[T],), {})  # error: [invalid-base]
+```
+
+## `Protocol` base
+
+Dynamic classes created via `type()` cannot inherit from `Protocol`:
+
+```py
+from typing import Protocol
+
+X = type("X", (Protocol,), {})  # error: [unsupported-dynamic-base]
+```
+
+## `TypedDict` base
+
+Dynamic classes created via `type()` cannot inherit from `TypedDict` directly. Use
+`TypedDict("Name", ...)` instead:
+
+```py
+from typing_extensions import TypedDict
+
+X = type("X", (TypedDict,), {})  # error: [invalid-base]
+```
+
+## Enum base
+
+Dynamic classes created via `type()` cannot inherit from Enum classes because `EnumMeta` expects
+special dict attributes that `type()` doesn't provide:
+
+```py
+from enum import Enum
+
+class MyEnum(Enum):
+    pass
+
+X = type("X", (MyEnum,), {})  # error: [invalid-base]
+```
+
+## Enum with members
+
+Enums with members are final and cannot be subclassed at all:
+
+```py
+from enum import Enum
+
+class Color(Enum):
+    RED = 1
+    GREEN = 2
+
+X = type("X", (Color,), {})  # error: [subclass-of-final-class]
+```

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

@@ -210,12 +210,15 @@ Narrowing does not occur in the same way if `type` is used to dynamically create
 
 ```py
 def _(x: str | int):
-    # Inline type() calls fall back to regular type overload matching.
-    # TODO: Once inline type() calls synthesize class types, this should narrow x to Never.
+    # The following diagnostic is valid, since the three-argument form of `type`
+    # can only be called with `str` as the first argument.
     #
-    # error: 13 [invalid-argument-type] "Argument to class `type` is incorrect: Expected `str`, found `str | int`"
+    # error: [invalid-argument-type] "Invalid argument to parameter 1 (`name`) of `type()`: Expected `str`, found `str | int`"
     if type(x, (), {}) is str:
-        reveal_type(x)  # revealed: str | int
+        # But we synthesize a new class object as the result of a three-argument call to `type`,
+        # and we know that this synthesized class object is not the same object as the `str` class object,
+        # so here the type is narrowed to `Never`!
+        reveal_type(x)  # revealed: Never
     else:
         reveal_type(x)  # revealed: str | int
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/no_matching_overload…_-_No_matching_overload…_-_A_class_constructor_…_(dd9f8a8f736a329).snap

@@ -25,6 +25,7 @@ error[no-matching-overload]: No overload of class `type` matches arguments
 1 | type()  # error: [no-matching-overload]
   | ^^^^^^
   |
+help: `builtins.type()` can either be called with one or three positional arguments (got 0)
 info: rule `no-matching-overload` is enabled by default
 
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/type.md_-_Calls_to_`type()`_-_MRO_error_highlighti…_(12acd974e75461ea).snap

@@ -0,0 +1,34 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: type.md - Calls to `type()` - MRO error highlighting (snapshot)
+mdtest path: crates/ty_python_semantic/resources/mdtest/call/type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | class A: ...
+2 | 
+3 | Dup = type("Dup", (A, A), {})  # error: [duplicate-base]
+```
+
+# Diagnostics
+
+```
+error[duplicate-base]: Duplicate base class <class 'A'> in class `Dup`
+ --> src/mdtest_snippet.py:3:7
+  |
+1 | class A: ...
+2 |
+3 | Dup = type("Dup", (A, A), {})  # error: [duplicate-base]
+  |       ^^^^^^^^^^^^^^^^^^^^^^^
+  |
+info: rule `duplicate-base` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_Enum_base_(4873196c8b48364).snap

@@ -0,0 +1,39 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - Enum base
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from enum import Enum
+2 | 
+3 | class MyEnum(Enum):
+4 |     pass
+5 | 
+6 | X = type("X", (MyEnum,), {})  # error: [invalid-base]
+```
+
+# Diagnostics
+
+```
+error[invalid-base]: Invalid base for class created via `type()`
+ --> src/mdtest_snippet.py:6:16
+  |
+4 |     pass
+5 |
+6 | X = type("X", (MyEnum,), {})  # error: [invalid-base]
+  |                ^^^^^^ Has type `<class 'MyEnum'>`
+  |
+info: Creating an enum class via `type()` is not supported
+info: Consider using `Enum("X", [])` instead
+info: rule `invalid-base` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_Enum_with_members_(81bef9a8e1230854).snap

@@ -0,0 +1,38 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - Enum with members
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from enum import Enum
+2 | 
+3 | class Color(Enum):
+4 |     RED = 1
+5 |     GREEN = 2
+6 | 
+7 | X = type("X", (Color,), {})  # error: [subclass-of-final-class]
+```
+
+# Diagnostics
+
+```
+error[subclass-of-final-class]: Class `X` cannot inherit from final class `Color`
+ --> src/mdtest_snippet.py:7:16
+  |
+5 |     GREEN = 2
+6 |
+7 | X = type("X", (Color,), {})  # error: [subclass-of-final-class]
+  |                ^^^^^
+  |
+info: rule `subclass-of-final-class` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_`@final`_class_(ea69d237256b3762).snap

@@ -0,0 +1,38 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - `@final` class
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing import final
+2 | 
+3 | @final
+4 | class FinalClass:
+5 |     pass
+6 | 
+7 | X = type("X", (FinalClass,), {})  # error: [subclass-of-final-class]
+```
+
+# Diagnostics
+
+```
+error[subclass-of-final-class]: Class `X` cannot inherit from final class `FinalClass`
+ --> src/mdtest_snippet.py:7:16
+  |
+5 |     pass
+6 |
+7 | X = type("X", (FinalClass,), {})  # error: [subclass-of-final-class]
+  |                ^^^^^^^^^^
+  |
+info: rule `subclass-of-final-class` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_`Generic`_base_(d455f46a27cec685).snap

@@ -0,0 +1,38 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - `Generic` base
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing import Generic, TypeVar
+2 | 
+3 | T = TypeVar("T")
+4 | 
+5 | X = type("X", (Generic[T],), {})  # error: [invalid-base]
+```
+
+# Diagnostics
+
+```
+error[invalid-base]: Invalid base for class created via `type()`
+ --> src/mdtest_snippet.py:5:16
+  |
+3 | T = TypeVar("T")
+4 |
+5 | X = type("X", (Generic[T],), {})  # error: [invalid-base]
+  |                ^^^^^^^^^^ Has type `<special-form 'typing.Generic[T]'>`
+  |
+info: Classes created via `type()` cannot be generic
+info: Consider using `class X(Generic[...]): ...` instead
+info: rule `invalid-base` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_`Protocol`_base_(99c9bde73664dd51).snap

@@ -0,0 +1,36 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - `Protocol` base
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing import Protocol
+2 | 
+3 | X = type("X", (Protocol,), {})  # error: [unsupported-dynamic-base]
+```
+
+# Diagnostics
+
+```
+info[unsupported-dynamic-base]: Unsupported base for class created via `type()`
+ --> src/mdtest_snippet.py:3:16
+  |
+1 | from typing import Protocol
+2 |
+3 | X = type("X", (Protocol,), {})  # error: [unsupported-dynamic-base]
+  |                ^^^^^^^^ Has type `<special-form 'typing.Protocol'>`
+  |
+info: Classes created via `type()` cannot be protocols
+info: Consider using `class X(Protocol): ...` instead
+info: rule `unsupported-dynamic-base` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/unsupported_base_dyn…_-_Unsupported_base_for…_-_`TypedDict`_base_(6f76171c88fc8760).snap

@@ -0,0 +1,36 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: unsupported_base_dynamic_type.md - Unsupported base for dynamic `type()` classes - `TypedDict` base
+mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/unsupported_base_dynamic_type.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing_extensions import TypedDict
+2 | 
+3 | X = type("X", (TypedDict,), {})  # error: [invalid-base]
+```
+
+# Diagnostics
+
+```
+error[invalid-base]: Invalid base for class created via `type()`
+ --> src/mdtest_snippet.py:3:16
+  |
+1 | from typing_extensions import TypedDict
+2 |
+3 | X = type("X", (TypedDict,), {})  # error: [invalid-base]
+  |                ^^^^^^^^^ Has type `<special-form 'typing.TypedDict'>`
+  |
+info: Classes created via `type()` cannot be TypedDicts
+info: Consider using `TypedDict("X", {})` instead
+info: rule `invalid-base` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/subscript/alias.md

@@ -1,43 +0,0 @@
-# Subscripts involving type aliases
-
-Aliases are expanded during analysis of subscripts.
-
-```toml
-[environment]
-python-version = "3.12"
-```
-
-```py
-from typing_extensions import TypeAlias, Literal
-
-ImplicitTuple = tuple[str, int, int]
-PEP613Tuple: TypeAlias = tuple[str, int, int]
-type PEP695Tuple = tuple[str, int, int]
-
-ImplicitZero = Literal[0]
-PEP613Zero: TypeAlias = Literal[0]
-type PEP695Zero = Literal[0]
-
-def f(
-    implicit_tuple: ImplicitTuple,
-    pep_613_tuple: PEP613Tuple,
-    pep_695_tuple: PEP695Tuple,
-    implicit_zero: ImplicitZero,
-    pep_613_zero: PEP613Zero,
-    pep_695_zero: PEP695Zero,
-):
-    reveal_type(implicit_tuple[:2])  # revealed: tuple[str, int]
-    reveal_type(implicit_tuple[implicit_zero])  # revealed: str
-    reveal_type(implicit_tuple[pep_613_zero])  # revealed: str
-    reveal_type(implicit_tuple[pep_695_zero])  # revealed: str
-
-    reveal_type(pep_613_tuple[:2])  # revealed: tuple[str, int]
-    reveal_type(pep_613_tuple[implicit_zero])  # revealed: str
-    reveal_type(pep_613_tuple[pep_613_zero])  # revealed: str
-    reveal_type(pep_613_tuple[pep_695_zero])  # revealed: str
-
-    reveal_type(pep_695_tuple[:2])  # revealed: tuple[str, int]
-    reveal_type(pep_695_tuple[implicit_zero])  # revealed: str
-    reveal_type(pep_695_tuple[pep_613_zero])  # revealed: str
-    reveal_type(pep_695_tuple[pep_695_zero])  # revealed: str
-```

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

@@ -106,5 +106,5 @@ class Bar:
 def f(x: Foo):
     if isinstance(x, Bar):
         # TODO: should be `int`
-        reveal_type(x["whatever"])  # revealed: @Todo(Subscript expressions with intersections)
+        reveal_type(x["whatever"])  # revealed: @Todo(Subscript expressions on intersections)
 ```

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

@@ -80,17 +80,6 @@ def _(m: int, n: int, s2: str):
     reveal_type(substring2)  # revealed: str
 ```
 
-## LiteralString
-
-```py
-from typing_extensions import LiteralString
-
-def f(x: LiteralString):
-    reveal_type(x[0])  # revealed: LiteralString
-    reveal_type(x[True])  # revealed: LiteralString
-    reveal_type(x[1:42])  # revealed: LiteralString
-```
-
 ## Unsupported slice types
 
 ```py

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

@@ -430,5 +430,5 @@ class Bar: ...
 
 def test4(val: Intersection[tuple[Foo], tuple[Bar]]):
     # TODO: should be `Foo & Bar`
-    reveal_type(val[0])  # revealed: @Todo(Subscript expressions with intersections)
+    reveal_type(val[0])  # revealed: @Todo(Subscript expressions on intersections)
 ```

crates/ty_python_semantic/resources/mdtest/subscript/typevar.md

@@ -1,89 +0,0 @@
-# Subscripts involving type variables
-
-## TypeVar bound/constrained to a tuple/int-literal/bool-literal
-
-The upper bounds of type variables are considered when analysing subscripts.
-
-```toml
-[environment]
-python-version = "3.12"
-```
-
-```py
-from typing_extensions import TypeAlias, Literal
-
-ImplicitTuple = tuple[str, int, int]
-PEP613Tuple: TypeAlias = tuple[str, int, int]
-type PEP695Tuple = tuple[str, int, int]
-
-ImplicitZero = Literal[0]
-PEP613Zero: TypeAlias = Literal[0]
-type PEP695Zero = Literal[0]
-
-# fmt: off
-
-def f[
-    BoundedTupleT: tuple[str, int, bytes],
-    ConstrainedTupleT: (tuple[str, int, bytes], tuple[int, bytes, str]),
-    BoundedZeroT: Literal[0],
-    ConstrainedIntLiteralT: (Literal[0], Literal[1])
-](
-    tuple_1: BoundedTupleT,
-    tuple_2: ConstrainedTupleT,
-    zero: BoundedZeroT,
-    some_integer: ConstrainedIntLiteralT,
-):
-    # TODO: would ideally be `tuple[str, int]`
-    reveal_type(tuple_1[:2])  # revealed: tuple[str | int | bytes, ...]
-    reveal_type(tuple_1[zero])  # revealed: str
-
-    # TODO: ideally this might be `str | int`,
-    # but it's hard to do that without introducing false positives elsewhere
-    reveal_type(tuple_1[some_integer])  # revealed: str | int | bytes
-
-    # TODO: would ideally be `tuple[str, int] | tuple[int, bytes]`
-    reveal_type(tuple_2[:2])  # revealed: tuple[str | int | bytes, ...]
-    reveal_type(tuple_2[zero])  # revealed: str | int
-    reveal_type(tuple_2[some_integer])  # revealed: str | int | bytes
-
-# fmt: on
-```
-
-## TypeVars
-
-```toml
-[environment]
-python-version = "3.12"
-```
-
-```py
-from typing import Protocol
-
-class SupportsLessThan(Protocol):
-    def __lt__(self, other, /) -> bool: ...
-
-def f[K: SupportsLessThan](dictionary: dict[K, int], key: K):
-    reveal_type(dictionary[key])  # revealed: int
-```
-
-## ParamSpecs
-
-```toml
-[environment]
-python-version = "3.12"
-```
-
-```py
-from typing import Callable
-
-def decorator[**P, T](func: Callable[P, T]) -> Callable[P, T]:
-    def inner(*args: P.args, **kwargs: P.kwargs) -> T:
-        if len(args) > 0:
-            # error: [invalid-assignment]
-            args = args[1:]
-
-        # `func` requires the full `ParamSpec` passed into `decorator`,
-        # but here the first argument is skipped, so we should possibly emit an error here:
-        return func(*args, **kwargs)
-    return inner
-```

crates/ty_python_semantic/src/semantic_index/definition.rs

@@ -938,6 +938,18 @@ impl DefinitionKind<'_> {
             | DefinitionKind::ExceptHandler(_) => DefinitionCategory::Binding,
         }
     }
+
+    /// Returns the value expression for assignment-based definitions.
+    ///
+    /// Returns `Some` for `Assignment` and `AnnotatedAssignment` (if it has a value),
+    /// `None` for all other definition kinds.
+    pub(crate) fn value<'ast>(&self, module: &'ast ParsedModuleRef) -> Option<&'ast ast::Expr> {
+        match self {
+            DefinitionKind::Assignment(assignment) => Some(assignment.value(module)),
+            DefinitionKind::AnnotatedAssignment(assignment) => assignment.value(module),
+            _ => None,
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Hash, get_size2::GetSize)]

crates/ty_python_semantic/src/semantic_index/scope.rs

@@ -2,7 +2,7 @@ use std::ops::Range;
 
 use ruff_db::{files::File, parsed::ParsedModuleRef};
 use ruff_index::newtype_index;
-use ruff_python_ast as ast;
+use ruff_python_ast::{self as ast, NodeIndex};
 
 use crate::{
     Db,
@@ -463,6 +463,27 @@ impl NodeWithScopeKind {
             _ => None,
         }
     }
+
+    /// Returns the anchor node index for this scope, or `None` for the module scope.
+    ///
+    /// This is used to compute relative node indices for expressions within the scope,
+    /// providing a stable anchor that only changes when the scope-introducing node changes.
+    pub(crate) fn node_index(&self) -> Option<NodeIndex> {
+        match self {
+            Self::Module => None,
+            Self::Class(class) => Some(class.index()),
+            Self::ClassTypeParameters(class) => Some(class.index()),
+            Self::Function(function) => Some(function.index()),
+            Self::FunctionTypeParameters(function) => Some(function.index()),
+            Self::TypeAlias(type_alias) => Some(type_alias.index()),
+            Self::TypeAliasTypeParameters(type_alias) => Some(type_alias.index()),
+            Self::Lambda(lambda) => Some(lambda.index()),
+            Self::ListComprehension(comp) => Some(comp.index()),
+            Self::SetComprehension(comp) => Some(comp.index()),
+            Self::DictComprehension(comp) => Some(comp.index()),
+            Self::GeneratorExpression(generator) => Some(generator.index()),
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, get_size2::GetSize)]

crates/ty_python_semantic/src/types.rs

@@ -485,6 +485,7 @@ macro_rules! todo_type {
 pub use crate::types::definition::TypeDefinition;
 use crate::types::relation::{
     HasRelationToVisitor, IsDisjointVisitor, IsEquivalentVisitor, TypeRelation,
+    default_equivalent_visitor,
 };
 pub(crate) use todo_type;
 
@@ -587,7 +588,7 @@ impl<'db> PropertyInstanceType<'db> {
         other: Self,
         inferable: InferableTypeVars<'_, 'db>,
     ) -> ConstraintSet<'db> {
-        self.is_equivalent_to_impl(db, other, inferable, &IsEquivalentVisitor::default())
+        self.is_equivalent_to_impl(db, other, inferable, &default_equivalent_visitor(db))
     }
 
     fn is_equivalent_to_impl(
@@ -599,27 +600,27 @@ impl<'db> PropertyInstanceType<'db> {
     ) -> ConstraintSet<'db> {
         let getter_equivalence = if let Some(getter) = self.getter(db) {
             let Some(other_getter) = other.getter(db) else {
-                return ConstraintSet::from(false);
+                return ConstraintSet::from_bool(db, false);
             };
             getter.is_equivalent_to_impl(db, other_getter, inferable, visitor)
         } else {
             if other.getter(db).is_some() {
-                return ConstraintSet::from(false);
+                return ConstraintSet::from_bool(db, false);
             }
-            ConstraintSet::from(true)
+            ConstraintSet::from_bool(db, true)
         };
 
         let setter_equivalence = || {
             if let Some(setter) = self.setter(db) {
                 let Some(other_setter) = other.setter(db) else {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 };
                 setter.is_equivalent_to_impl(db, other_setter, inferable, visitor)
             } else {
                 if other.setter(db).is_some() {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
         };
 
@@ -4111,55 +4112,6 @@ impl<'db> Type<'db> {
                     .into()
                 }
 
-                Some(KnownClass::Type) => {
-                    let str_instance = KnownClass::Str.to_instance(db);
-                    let type_instance = KnownClass::Type.to_instance(db);
-
-                    // ```py
-                    // class type:
-                    //     @overload
-                    //     def __init__(self, o: object, /) -> None: ...
-                    //     @overload
-                    //     def __init__(self, name: str, bases: tuple[type, ...], dict: dict[str, Any], /, **kwds: Any) -> None: ...
-                    // ```
-                    CallableBinding::from_overloads(
-                        self,
-                        [
-                            Signature::new(
-                                Parameters::new(
-                                    db,
-                                    [Parameter::positional_only(Some(Name::new_static("o")))
-                                        .with_annotated_type(Type::any())],
-                                ),
-                                type_instance,
-                            ),
-                            Signature::new(
-                                Parameters::new(
-                                    db,
-                                    [
-                                        Parameter::positional_only(Some(Name::new_static("name")))
-                                            .with_annotated_type(str_instance),
-                                        Parameter::positional_only(Some(Name::new_static("bases")))
-                                            .with_annotated_type(Type::homogeneous_tuple(
-                                                db,
-                                                type_instance,
-                                            )),
-                                        Parameter::positional_only(Some(Name::new_static("dict")))
-                                            .with_annotated_type(
-                                                KnownClass::Dict.to_specialized_instance(
-                                                    db,
-                                                    &[str_instance, Type::any()],
-                                                ),
-                                            ),
-                                    ],
-                                ),
-                                type_instance,
-                            ),
-                        ],
-                    )
-                    .into()
-                }
-
                 Some(KnownClass::Object) => {
                     // ```py
                     // class object:
@@ -6559,9 +6511,9 @@ impl<'db> Type<'db> {
                 Some(TypeDefinition::Function(function.definition(db)))
             }
             Self::ModuleLiteral(module) => Some(TypeDefinition::Module(module.module(db))),
-            Self::ClassLiteral(class_literal) => Some(class_literal.type_definition(db)),
+            Self::ClassLiteral(class_literal) => class_literal.type_definition(db),
             Self::GenericAlias(alias) => Some(TypeDefinition::StaticClass(alias.definition(db))),
-            Self::NominalInstance(instance) => Some(instance.class(db).type_definition(db)),
+            Self::NominalInstance(instance) => instance.class(db).type_definition(db),
             Self::KnownInstance(instance) => match instance {
                 KnownInstanceType::TypeVar(var) => {
                     Some(TypeDefinition::TypeVar(var.definition(db)?))
@@ -6575,7 +6527,7 @@ impl<'db> Type<'db> {
 
             Self::SubclassOf(subclass_of_type) => match subclass_of_type.subclass_of() {
                 SubclassOfInner::Dynamic(_) => None,
-                SubclassOfInner::Class(class) => Some(class.type_definition(db)),
+                SubclassOfInner::Class(class) => class.type_definition(db),
                 SubclassOfInner::TypeVar(bound_typevar) => {
                     Some(TypeDefinition::TypeVar(bound_typevar.typevar(db).definition(db)?))
                 }
@@ -6605,7 +6557,7 @@ impl<'db> Type<'db> {
             Self::TypeVar(bound_typevar) => Some(TypeDefinition::TypeVar(bound_typevar.typevar(db).definition(db)?)),
 
             Self::ProtocolInstance(protocol) => match protocol.inner {
-                Protocol::FromClass(class) => Some(class.type_definition(db)),
+                Protocol::FromClass(class) => class.type_definition(db),
                 Protocol::Synthesized(_) => None,
             },
 
@@ -10555,7 +10507,7 @@ impl<'db> CallableType<'db> {
         disjointness_visitor: &IsDisjointVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if other.is_function_like(db) && !self.is_function_like(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         self.signatures(db).has_relation_to_impl(
@@ -10579,13 +10531,20 @@ impl<'db> CallableType<'db> {
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
-        ConstraintSet::from(self.is_function_like(db) == other.is_function_like(db)).and(db, || {
-            self.signatures(db)
-                .is_equivalent_to_impl(db, other.signatures(db), inferable, visitor)
-        })
+        ConstraintSet::from_bool(db, self.is_function_like(db) == other.is_function_like(db)).and(
+            db,
+            || {
+                self.signatures(db).is_equivalent_to_impl(
+                    db,
+                    other.signatures(db),
+                    inferable,
+                    visitor,
+                )
+            },
+        )
     }
 }
 
@@ -10770,7 +10729,7 @@ impl<'db> KnownBoundMethodType<'db> {
             ) => self_property.when_equivalent_to(db, other_property, inferable),
 
             (KnownBoundMethodType::StrStartswith(_), KnownBoundMethodType::StrStartswith(_)) => {
-                ConstraintSet::from(self == other)
+                ConstraintSet::from_bool(db, self == other)
             }
 
             (
@@ -10800,7 +10759,7 @@ impl<'db> KnownBoundMethodType<'db> {
             | (
                 KnownBoundMethodType::GenericContextSpecializeConstrained(_),
                 KnownBoundMethodType::GenericContextSpecializeConstrained(_),
-            ) => ConstraintSet::from(true),
+            ) => ConstraintSet::from_bool(db, true),
 
             (
                 KnownBoundMethodType::FunctionTypeDunderGet(_)
@@ -10827,7 +10786,7 @@ impl<'db> KnownBoundMethodType<'db> {
                 | KnownBoundMethodType::ConstraintSetSatisfies(_)
                 | KnownBoundMethodType::ConstraintSetSatisfiedByAllTypeVars(_)
                 | KnownBoundMethodType::GenericContextSpecializeConstrained(_),
-            ) => ConstraintSet::from(false),
+            ) => ConstraintSet::from_bool(db, false),
         }
     }
 
@@ -10859,7 +10818,7 @@ impl<'db> KnownBoundMethodType<'db> {
             ) => self_property.is_equivalent_to_impl(db, other_property, inferable, visitor),
 
             (KnownBoundMethodType::StrStartswith(_), KnownBoundMethodType::StrStartswith(_)) => {
-                ConstraintSet::from(self == other)
+                ConstraintSet::from_bool(db, self == other)
             }
 
             (
@@ -10873,7 +10832,7 @@ impl<'db> KnownBoundMethodType<'db> {
             | (
                 KnownBoundMethodType::ConstraintSetNever,
                 KnownBoundMethodType::ConstraintSetNever,
-            ) => ConstraintSet::from(true),
+            ) => ConstraintSet::from_bool(db, true),
 
             (
                 KnownBoundMethodType::ConstraintSetImpliesSubtypeOf(left_constraints),
@@ -10893,7 +10852,7 @@ impl<'db> KnownBoundMethodType<'db> {
             (
                 KnownBoundMethodType::GenericContextSpecializeConstrained(left_generic_context),
                 KnownBoundMethodType::GenericContextSpecializeConstrained(right_generic_context),
-            ) => ConstraintSet::from(left_generic_context == right_generic_context),
+            ) => ConstraintSet::from_bool(db, left_generic_context == right_generic_context),
 
             (
                 KnownBoundMethodType::FunctionTypeDunderGet(_)
@@ -10920,7 +10879,7 @@ impl<'db> KnownBoundMethodType<'db> {
                 | KnownBoundMethodType::ConstraintSetSatisfies(_)
                 | KnownBoundMethodType::ConstraintSetSatisfiedByAllTypeVars(_)
                 | KnownBoundMethodType::GenericContextSpecializeConstrained(_),
-            ) => ConstraintSet::from(false),
+            ) => ConstraintSet::from_bool(db, false),
         }
     }
 
@@ -12120,23 +12079,23 @@ impl<'db> UnionType<'db> {
         _visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         let self_elements = self.elements(db);
         let other_elements = other.elements(db);
 
         if self_elements.len() != other_elements.len() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         let sorted_self = self.normalized(db);
 
         if sorted_self == Type::Union(other) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
-        ConstraintSet::from(sorted_self == other.normalized(db))
+        ConstraintSet::from_bool(db, sorted_self == other.normalized(db))
     }
 
     /// Identify some specific unions of known classes, currently the ones that `float` and
@@ -12530,30 +12489,30 @@ impl<'db> IntersectionType<'db> {
         _visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         let self_positive = self.positive(db);
         let other_positive = other.positive(db);
 
         if self_positive.len() != other_positive.len() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         let self_negative = self.negative(db);
         let other_negative = other.negative(db);
 
         if self_negative.len() != other_negative.len() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         let sorted_self = self.normalized(db);
 
         if sorted_self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
-        ConstraintSet::from(sorted_self == other.normalized(db))
+        ConstraintSet::from_bool(db, sorted_self == other.normalized(db))
     }
 
     /// Returns an iterator over the positive elements of the intersection. If

crates/ty_python_semantic/src/types/call/bind.rs

@@ -1313,7 +1313,7 @@ impl<'db> Bindings<'db> {
                         if !overload.parameter_types().is_empty() {
                             return;
                         }
-                        let constraints = ConstraintSet::from(true);
+                        let constraints = ConstraintSet::from_bool(db, true);
                         let tracked = TrackedConstraintSet::new(db, constraints);
                         overload.set_return_type(Type::KnownInstance(
                             KnownInstanceType::ConstraintSet(tracked),
@@ -1324,7 +1324,7 @@ impl<'db> Bindings<'db> {
                         if !overload.parameter_types().is_empty() {
                             return;
                         }
-                        let constraints = ConstraintSet::from(false);
+                        let constraints = ConstraintSet::from_bool(db, false);
                         let tracked = TrackedConstraintSet::new(db, constraints);
                         overload.set_return_type(Type::KnownInstance(
                             KnownInstanceType::ConstraintSet(tracked),
@@ -1443,12 +1443,6 @@ impl<'db> Bindings<'db> {
                             }
                         }
 
-                        Some(KnownClass::Type) if overload_index == 0 => {
-                            if let [Some(arg)] = overload.parameter_types() {
-                                overload.set_return_type(arg.dunder_class(db));
-                            }
-                        }
-
                         Some(KnownClass::Property) => {
                             if let [getter, setter, ..] = overload.parameter_types() {
                                 overload.set_return_type(Type::PropertyInstance(

crates/ty_python_semantic/src/types/class.rs

@@ -37,6 +37,7 @@ use crate::types::member::{Member, class_member};
 use crate::types::mro::{DynamicMroError, DynamicMroErrorKind};
 use crate::types::relation::{
     HasRelationToVisitor, IsDisjointVisitor, IsEquivalentVisitor, TypeRelation,
+    default_disjoint_visitor, default_relation_visitor,
 };
 use crate::types::signatures::{CallableSignature, Parameter, Parameters, Signature};
 use crate::types::tuple::{TupleSpec, TupleType};
@@ -60,7 +61,7 @@ use crate::{
         attribute_assignments,
         definition::{DefinitionKind, TargetKind},
         place_table,
-        scope::{FileScopeId, ScopeId},
+        scope::ScopeId,
         semantic_index, use_def_map,
     },
     types::{
@@ -74,7 +75,7 @@ use ruff_db::diagnostic::Span;
 use ruff_db::files::File;
 use ruff_db::parsed::{ParsedModuleRef, parsed_module};
 use ruff_python_ast::name::Name;
-use ruff_python_ast::{self as ast, PythonVersion};
+use ruff_python_ast::{self as ast, NodeIndex, PythonVersion};
 use ruff_text_size::{Ranged, TextRange};
 use rustc_hash::FxHashSet;
 use ty_module_resolver::{KnownModule, file_to_module};
@@ -562,25 +563,16 @@ impl<'db> ClassLiteral<'db> {
     }
 
     /// Returns the generic context if this is a generic class.
-    ///
-    // TODO: We should emit a diagnostic if a dynamic class (created via `type()`) attempts
-    // to inherit from `Generic[T]`, since dynamic classes can't be generic. See also: `is_protocol`.
     pub(crate) fn generic_context(self, db: &'db dyn Db) -> Option<GenericContext<'db>> {
         self.as_static().and_then(|class| class.generic_context(db))
     }
 
     /// Returns whether this class is a protocol.
-    ///
-    // TODO: We should emit a diagnostic if a dynamic class (created via `type()`) attempts
-    // to inherit from `Protocol`, since dynamic classes can't be protocols. See also: `generic_context`.
     pub(crate) fn is_protocol(self, db: &'db dyn Db) -> bool {
         self.as_static().is_some_and(|class| class.is_protocol(db))
     }
 
     /// Returns whether this class is a `TypedDict`.
-    // TODO: We should emit a diagnostic if a dynamic class (created via `type()`) attempts
-    // to inherit from `TypedDict`. To create a dynamic TypedDict, you should invoke
-    // `TypedDict` as a function, not `type`. See also: `generic_context`, `is_protocol`.
     pub fn is_typed_dict(self, db: &'db dyn Db) -> bool {
         match self {
             Self::Static(class) => class.is_typed_dict(db),
@@ -613,7 +605,7 @@ impl<'db> ClassLiteral<'db> {
     pub(crate) fn file(self, db: &dyn Db) -> File {
         match self {
             Self::Static(class) => class.file(db),
-            Self::Dynamic(class) => class.file(db),
+            Self::Dynamic(class) => class.scope(db).file(db),
         }
     }
 
@@ -634,10 +626,12 @@ impl<'db> ClassLiteral<'db> {
     }
 
     /// Returns whether this class is final.
-    // TODO: Support `@final` on dynamic classes, e.g. `X = final(type("X", (), {}))`.
-    // We should either recognize and track this, or emit a diagnostic if unsupported.
     pub(crate) fn is_final(self, db: &'db dyn Db) -> bool {
-        self.as_static().is_some_and(|class| class.is_final(db))
+        match self {
+            Self::Static(class) => class.is_final(db),
+            // Dynamic classes created via `type()` cannot be marked as final.
+            Self::Dynamic(_) => false,
+        }
     }
 
     /// Returns `true` if this class defines any ordering method (`__lt__`, `__le__`, `__gt__`,
@@ -664,10 +658,10 @@ impl<'db> ClassLiteral<'db> {
         }
     }
 
-    /// Returns the definition of this class.
-    pub(crate) fn definition(self, db: &'db dyn Db) -> Definition<'db> {
+    /// Returns the definition of this class, if available.
+    pub(crate) fn definition(self, db: &'db dyn Db) -> Option<Definition<'db>> {
         match self {
-            Self::Static(class) => class.definition(db),
+            Self::Static(class) => Some(class.definition(db)),
             Self::Dynamic(class) => class.definition(db),
         }
     }
@@ -675,11 +669,11 @@ impl<'db> ClassLiteral<'db> {
     /// Returns the type definition for this class.
     ///
     /// For static classes, returns `TypeDefinition::StaticClass`.
-    /// For dynamic classes, returns `TypeDefinition::DynamicClass`.
-    pub(crate) fn type_definition(self, db: &'db dyn Db) -> TypeDefinition<'db> {
+    /// For dynamic classes, returns `TypeDefinition::DynamicClass` if a definition is available.
+    pub(crate) fn type_definition(self, db: &'db dyn Db) -> Option<TypeDefinition<'db>> {
         match self {
-            Self::Static(class) => TypeDefinition::StaticClass(class.definition(db)),
-            Self::Dynamic(class) => TypeDefinition::DynamicClass(class.definition(db)),
+            Self::Static(class) => Some(TypeDefinition::StaticClass(class.definition(db))),
+            Self::Dynamic(class) => class.definition(db).map(TypeDefinition::DynamicClass),
         }
     }
 
@@ -944,13 +938,13 @@ impl<'db> ClassType<'db> {
         self.class_literal(db).known(db)
     }
 
-    /// Returns the definition for this class.
-    pub(crate) fn definition(self, db: &'db dyn Db) -> Definition<'db> {
+    /// Returns the definition for this class, if available.
+    pub(crate) fn definition(self, db: &'db dyn Db) -> Option<Definition<'db>> {
         self.class_literal(db).definition(db)
     }
 
     /// Returns the type definition for this class.
-    pub(crate) fn type_definition(self, db: &'db dyn Db) -> TypeDefinition<'db> {
+    pub(crate) fn type_definition(self, db: &'db dyn Db) -> Option<TypeDefinition<'db>> {
         self.class_literal(db).type_definition(db)
     }
 
@@ -1070,8 +1064,8 @@ impl<'db> ClassType<'db> {
             other,
             inferable,
             TypeRelation::Subtyping,
-            &HasRelationToVisitor::default(),
-            &IsDisjointVisitor::default(),
+            &default_relation_visitor(db),
+            &default_disjoint_visitor(db),
         )
     }
 
@@ -1090,42 +1084,45 @@ impl<'db> ClassType<'db> {
                     TypeRelation::Subtyping
                     | TypeRelation::Redundancy
                     | TypeRelation::SubtypingAssuming(_) => {
-                        ConstraintSet::from(other.is_object(db))
+                        ConstraintSet::from_bool(db, other.is_object(db))
                     }
                     TypeRelation::Assignability | TypeRelation::ConstraintSetAssignability => {
-                        ConstraintSet::from(!other.is_final(db))
+                        ConstraintSet::from_bool(db, !other.is_final(db))
                     }
                 },
 
                 // Protocol, Generic, and TypedDict are special bases that don't match ClassType.
                 ClassBase::Protocol | ClassBase::Generic | ClassBase::TypedDict => {
-                    ConstraintSet::from(false)
+                    ConstraintSet::from_bool(db, false)
                 }
 
                 ClassBase::Class(base) => match (base, other) {
                     // Two non-generic classes match if they have the same class literal.
                     (ClassType::NonGeneric(base_literal), ClassType::NonGeneric(other_literal)) => {
-                        ConstraintSet::from(base_literal == other_literal)
+                        ConstraintSet::from_bool(db, base_literal == other_literal)
                     }
 
                     // Two generic classes match if they have the same origin and compatible specializations.
                     (ClassType::Generic(base), ClassType::Generic(other)) => {
-                        ConstraintSet::from(base.origin(db) == other.origin(db)).and(db, || {
-                            base.specialization(db).has_relation_to_impl(
-                                db,
-                                other.specialization(db),
-                                inferable,
-                                relation,
-                                relation_visitor,
-                                disjointness_visitor,
-                            )
-                        })
+                        ConstraintSet::from_bool(db, base.origin(db) == other.origin(db)).and(
+                            db,
+                            || {
+                                base.specialization(db).has_relation_to_impl(
+                                    db,
+                                    other.specialization(db),
+                                    inferable,
+                                    relation,
+                                    relation_visitor,
+                                    disjointness_visitor,
+                                )
+                            },
+                        )
                     }
 
                     // Generic and non-generic classes don't match.
                     (ClassType::Generic(_), ClassType::NonGeneric(_))
                     | (ClassType::NonGeneric(_), ClassType::Generic(_)) => {
-                        ConstraintSet::from(false)
+                        ConstraintSet::from_bool(db, false)
                     }
                 },
             }
@@ -1140,18 +1137,18 @@ impl<'db> ClassType<'db> {
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         match (self, other) {
             // Two non-generic classes are only equivalent if they are equal (handled above).
             // A non-generic class is never equivalent to a generic class.
             (ClassType::NonGeneric(_), _) | (_, ClassType::NonGeneric(_)) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             (ClassType::Generic(this), ClassType::Generic(other)) => {
-                ConstraintSet::from(this.origin(db) == other.origin(db)).and(db, || {
+                ConstraintSet::from_bool(db, this.origin(db) == other.origin(db)).and(db, || {
                     this.specialization(db).is_equivalent_to_impl(
                         db,
                         other.specialization(db),
@@ -4704,12 +4701,8 @@ impl<'db> VarianceInferable<'db> for ClassLiteral<'db> {
 ///
 /// # Salsa interning
 ///
-/// Each `type()` call is uniquely identified by its [`Definition`], which provides
-/// stable identity without depending on AST node indices that can change when code
-/// is inserted above the call site.
-///
-/// Two different `type()` calls always produce distinct `DynamicClassLiteral`
-/// instances, even if they have the same name and bases:
+/// This is a Salsa-interned struct. Two different `type()` calls always produce
+/// distinct `DynamicClassLiteral` instances, even if they have the same name and bases:
 ///
 /// ```python
 /// Foo1 = type("Foo", (Base,), {})
@@ -4717,9 +4710,11 @@ impl<'db> VarianceInferable<'db> for ClassLiteral<'db> {
 /// # Foo1 and Foo2 are distinct types
 /// ```
 ///
-/// Note: Only assigned `type()` calls are currently supported (e.g., `Foo = type(...)`).
-/// Inline calls like `process(type(...))` fall back to normal call handling.
-#[salsa::interned(debug, heap_size = ruff_memory_usage::heap_size)]
+/// The `anchor` field provides stable identity:
+/// - For assigned `type()` calls, the `Definition` uniquely identifies the class.
+/// - For dangling `type()` calls, a relative node offset anchored to the enclosing scope
+///   provides stable identity that only changes when the scope itself changes.
+#[salsa::interned(debug, heap_size=ruff_memory_usage::heap_size)]
 #[derive(PartialOrd, Ord)]
 pub struct DynamicClassLiteral<'db> {
     /// The name of the class (from the first argument to `type()`).
@@ -4730,8 +4725,13 @@ pub struct DynamicClassLiteral<'db> {
     #[returns(deref)]
     pub bases: Box<[ClassBase<'db>]>,
 
-    /// The definition where this class is created.
-    pub definition: Definition<'db>,
+    /// The anchor for this dynamic class, providing stable identity.
+    ///
+    /// - `Definition`: The `type()` call is assigned to a variable. The definition
+    ///   uniquely identifies this class and can be used to find the `type()` call.
+    /// - `ScopeOffset`: The `type()` call is "dangling" (not assigned). The offset
+    ///   is relative to the enclosing scope's anchor node index.
+    pub anchor: DynamicClassAnchor<'db>,
 
     /// The class members from the namespace dict (third argument to `type()`).
     /// Each entry is a (name, type) pair extracted from the dict literal.
@@ -4748,38 +4748,87 @@ pub struct DynamicClassLiteral<'db> {
     pub dataclass_params: Option<DataclassParams<'db>>,
 }
 
+/// Anchor for identifying a dynamic class literal.
+///
+/// This enum provides stable identity for `DynamicClassLiteral`:
+/// - For assigned calls, the `Definition` uniquely identifies the class.
+/// - For dangling calls, a relative offset provides stable identity.
+#[derive(
+    Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, salsa::Update, get_size2::GetSize,
+)]
+pub enum DynamicClassAnchor<'db> {
+    /// The `type()` call is assigned to a variable.
+    ///
+    /// The `Definition` uniquely identifies this class. The `type()` call expression
+    /// is the `value` of the assignment, so we can get its range from the definition.
+    Definition(Definition<'db>),
+
+    /// The `type()` call is "dangling" (not assigned to a variable).
+    ///
+    /// The offset is relative to the enclosing scope's anchor node index.
+    /// For module scope, this is equivalent to an absolute index (anchor is 0).
+    ScopeOffset { scope: ScopeId<'db>, offset: u32 },
+}
+
 impl get_size2::GetSize for DynamicClassLiteral<'_> {}
 
 #[salsa::tracked]
 impl<'db> DynamicClassLiteral<'db> {
+    /// Returns the definition where this class is created, if it was assigned to a variable.
+    pub(crate) fn definition(self, db: &'db dyn Db) -> Option<Definition<'db>> {
+        match self.anchor(db) {
+            DynamicClassAnchor::Definition(definition) => Some(definition),
+            DynamicClassAnchor::ScopeOffset { .. } => None,
+        }
+    }
+
+    /// Returns the scope in which this dynamic class was created.
+    pub(crate) fn scope(self, db: &'db dyn Db) -> ScopeId<'db> {
+        match self.anchor(db) {
+            DynamicClassAnchor::Definition(definition) => definition.scope(db),
+            DynamicClassAnchor::ScopeOffset { scope, .. } => scope,
+        }
+    }
+
     /// Returns a [`Span`] with the range of the `type()` call expression.
     ///
     /// See [`Self::header_range`] for more details.
     pub(super) fn header_span(self, db: &'db dyn Db) -> Span {
-        Span::from(self.file(db)).with_range(self.header_range(db))
+        Span::from(self.scope(db).file(db)).with_range(self.header_range(db))
     }
 
     /// Returns the range of the `type()` call expression that created this class.
     pub(super) fn header_range(self, db: &'db dyn Db) -> TextRange {
-        let definition = self.definition(db);
-        let file = definition.file(db);
+        let scope = self.scope(db);
+        let file = scope.file(db);
         let module = parsed_module(db, file).load(db);
 
-        // Dynamic classes are only created from regular assignments (e.g., `Foo = type(...)`).
-        let DefinitionKind::Assignment(assignment) = definition.kind(db) else {
-            unreachable!("DynamicClassLiteral should only be created from Assignment definitions");
-        };
-        assignment.value(&module).range()
-    }
+        match self.anchor(db) {
+            DynamicClassAnchor::Definition(definition) => {
+                // For definitions, get the range from the definition's value.
+                // The `type()` call is the value of the assignment.
+                definition
+                    .kind(db)
+                    .value(&module)
+                    .expect("DynamicClassAnchor::Definition should only be used for assignments")
+                    .range()
+            }
+            DynamicClassAnchor::ScopeOffset { offset, .. } => {
+                // For dangling `type()` calls, compute the absolute index from the offset.
+                let scope_anchor = scope.node(db).node_index().unwrap_or(NodeIndex::from(0));
+                let anchor_u32 = scope_anchor
+                    .as_u32()
+                    .expect("anchor should not be NodeIndex::NONE");
+                let absolute_index = NodeIndex::from(anchor_u32 + offset);
 
-    /// Returns the file containing the `type()` call.
-    pub(crate) fn file(self, db: &'db dyn Db) -> File {
-        self.definition(db).file(db)
-    }
-
-    /// Returns the scope containing the `type()` call.
-    pub(crate) fn file_scope(self, db: &'db dyn Db) -> FileScopeId {
-        self.definition(db).file_scope(db)
+                // Get the node and return its range.
+                let node: &ast::ExprCall = module
+                    .get_by_index(absolute_index)
+                    .try_into()
+                    .expect("scope offset should point to ExprCall");
+                node.range()
+            }
+        }
     }
 
     /// Get the metaclass of this dynamic class.
@@ -5020,7 +5069,7 @@ impl<'db> DynamicClassLiteral<'db> {
             db,
             self.name(db).clone(),
             self.bases(db),
-            self.definition(db),
+            self.anchor(db),
             self.members(db),
             self.has_dynamic_namespace(db),
             dataclass_params,
@@ -5314,7 +5363,8 @@ impl<'db> QualifiedClassName<'db> {
             }
             ClassLiteral::Dynamic(class) => {
                 // Dynamic classes don't have a body scope; start from the enclosing scope.
-                (class.file(self.db), class.file_scope(self.db), 0)
+                let scope = class.scope(self.db);
+                (scope.file(self.db), scope.file_scope_id(self.db), 0)
             }
         };
 
@@ -6477,7 +6527,7 @@ impl KnownClass {
         db: &'db dyn Db,
         other: ClassType<'db>,
     ) -> ConstraintSet<'db> {
-        ConstraintSet::from(self.is_subclass_of(db, other))
+        ConstraintSet::from_bool(db, self.is_subclass_of(db, other))
     }
 
     /// Return the module in which we should look up the definition for this class

crates/ty_python_semantic/src/types/diagnostic.rs

@@ -104,6 +104,7 @@ pub(crate) fn register_lints(registry: &mut LintRegistryBuilder) {
     registry.register_lint(&POSSIBLY_UNRESOLVED_REFERENCE);
     registry.register_lint(&SUBCLASS_OF_FINAL_CLASS);
     registry.register_lint(&OVERRIDE_OF_FINAL_METHOD);
+    registry.register_lint(&INEFFECTIVE_FINAL);
     registry.register_lint(&TYPE_ASSERTION_FAILURE);
     registry.register_lint(&TOO_MANY_POSITIONAL_ARGUMENTS);
     registry.register_lint(&UNAVAILABLE_IMPLICIT_SUPER_ARGUMENTS);
@@ -1789,6 +1790,34 @@ declare_lint! {
     }
 }
 
+declare_lint! {
+    /// ## What it does
+    /// Checks for calls to `final()` that type checkers cannot interpret.
+    ///
+    /// ## Why is this bad?
+    /// The `final()` function is designed to be used as a decorator. When called directly
+    /// as a function (e.g., `final(type(...))`), type checkers will not understand the
+    /// application of `final` and will not prevent subclassing.
+    ///
+    /// ## Example
+    ///
+    /// ```python
+    /// from typing import final
+    ///
+    /// # Incorrect: type checkers will not prevent subclassing
+    /// MyClass = final(type("MyClass", (), {}))
+    ///
+    /// # Correct: use `final` as a decorator
+    /// @final
+    /// class MyClass: ...
+    /// ```
+    pub(crate) static INEFFECTIVE_FINAL = {
+        summary: "detects calls to `final()` that type checkers cannot interpret",
+        status: LintStatus::preview("0.0.1-alpha.33"),
+        default_level: Level::Warn,
+    }
+}
+
 declare_lint! {
     /// ## What it does
     /// Checks for methods that are decorated with `@override` but do not override any method in a superclass.

crates/ty_python_semantic/src/types/enums.rs

@@ -67,7 +67,6 @@ pub(crate) fn enum_metadata<'db>(
             //
             // MyEnum = type("MyEnum", (BaseEnum,), {"A": 1, "B": 2})
             // ```
-            // TODO: Add a diagnostic for including an enum in a `type(...)` call.
             return None;
         }
     };

crates/ty_python_semantic/src/types/function.rs

@@ -1123,7 +1123,7 @@ impl<'db> FunctionType<'db> {
         disjointness_visitor: &IsDisjointVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self.literal(db) != other.literal(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         let self_signature = self.signature(db);
@@ -1146,10 +1146,10 @@ impl<'db> FunctionType<'db> {
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self.normalized(db) == other.normalized(db) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
         if self.literal(db) != other.literal(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
         let self_signature = self.signature(db);
         let other_signature = other.signature(db);

crates/ty_python_semantic/src/types/generics.rs

@@ -17,6 +17,7 @@ use crate::types::constraints::{ConstraintSet, IteratorConstraintsExtension};
 use crate::types::instance::{Protocol, ProtocolInstanceType};
 use crate::types::relation::{
     HasRelationToVisitor, IsDisjointVisitor, IsEquivalentVisitor, TypeRelation,
+    default_disjoint_visitor, default_relation_visitor,
 };
 use crate::types::signatures::Parameters;
 use crate::types::tuple::{TupleSpec, TupleType, walk_tuple_type};
@@ -96,7 +97,7 @@ pub(crate) fn typing_self<'db>(
     let identity = TypeVarIdentity::new(
         db,
         ast::name::Name::new_static("Self"),
-        Some(class.definition(db)),
+        class.definition(db),
         TypeVarKind::TypingSelf,
     );
     let bounds = TypeVarBoundOrConstraints::UpperBound(Type::instance(
@@ -793,12 +794,12 @@ fn is_subtype_in_invariant_position<'db>(
         // This should be removed and properly handled in the respective
         // `(Type::TypeVar(_), _) | (_, Type::TypeVar(_))` branch of
         // `Type::has_relation_to_impl`. Right now, we cannot generally
-        // return `ConstraintSet::from(true)` from that branch, as that
+        // return `ConstraintSet::from_bool(db, true)` from that branch, as that
         // leads to union simplification, which means that we lose track
         // of type variables without recording the constraints under which
         // the relation holds.
         if matches!(base, Type::TypeVar(_)) || matches!(derived, Type::TypeVar(_)) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         derived.has_relation_to_impl(
@@ -1272,7 +1273,7 @@ impl<'db> Specialization<'db> {
     ) -> ConstraintSet<'db> {
         let generic_context = self.generic_context(db);
         if generic_context != other.generic_context(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         if let (Some(self_tuple), Some(other_tuple)) = (self.tuple_inner(db), other.tuple_inner(db))
@@ -1331,7 +1332,7 @@ impl<'db> Specialization<'db> {
                     relation_visitor,
                     disjointness_visitor,
                 ),
-                TypeVarVariance::Bivariant => ConstraintSet::from(true),
+                TypeVarVariance::Bivariant => ConstraintSet::from_bool(db, true),
             }
         })
     }
@@ -1346,8 +1347,8 @@ impl<'db> Specialization<'db> {
             db,
             other,
             inferable,
-            &IsDisjointVisitor::default(),
-            &HasRelationToVisitor::default(),
+            &default_disjoint_visitor(db),
+            &default_relation_visitor(db),
         )
     }
 
@@ -1361,7 +1362,7 @@ impl<'db> Specialization<'db> {
     ) -> ConstraintSet<'db> {
         let generic_context = self.generic_context(db);
         if generic_context != other.generic_context(db) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         if let (Some(self_tuple), Some(other_tuple)) = (self.tuple_inner(db), other.tuple_inner(db))
@@ -1399,13 +1400,13 @@ impl<'db> Specialization<'db> {
                 ),
 
                 // If `Foo[T]` is covariant in `T`, `Foo[Never]` is a subtype of `Foo[A]` and `Foo[B]`
-                TypeVarVariance::Covariant => ConstraintSet::from(false),
+                TypeVarVariance::Covariant => ConstraintSet::from_bool(db, false),
 
                 // If `Foo[T]` is contravariant in `T`, `Foo[A | B]` is a subtype of `Foo[A]` and `Foo[B]`
-                TypeVarVariance::Contravariant => ConstraintSet::from(false),
+                TypeVarVariance::Contravariant => ConstraintSet::from_bool(db, false),
 
                 // If `Foo[T]` is bivariant in `T`, `Foo[A]` and `Foo[B]` are mutual subtypes.
-                TypeVarVariance::Bivariant => ConstraintSet::from(false),
+                TypeVarVariance::Bivariant => ConstraintSet::from_bool(db, false),
             },
         )
     }
@@ -1418,14 +1419,14 @@ impl<'db> Specialization<'db> {
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self.materialization_kind(db) != other.materialization_kind(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
         let generic_context = self.generic_context(db);
         if generic_context != other.generic_context(db) {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
-        let mut result = ConstraintSet::from(true);
+        let mut result = ConstraintSet::from_bool(db, true);
         for ((bound_typevar, self_type), other_type) in generic_context
             .variables(db)
             .zip(self.types(db))
@@ -1443,7 +1444,7 @@ impl<'db> Specialization<'db> {
                 | TypeVarVariance::Contravariant => {
                     self_type.is_equivalent_to_impl(db, *other_type, inferable, visitor)
                 }
-                TypeVarVariance::Bivariant => ConstraintSet::from(true),
+                TypeVarVariance::Bivariant => ConstraintSet::from_bool(db, true),
             };
             if result.intersect(db, compatible).is_never_satisfied(db) {
                 return result;
@@ -1451,7 +1452,7 @@ impl<'db> Specialization<'db> {
         }
 
         match (self.tuple_inner(db), other.tuple_inner(db)) {
-            (Some(_), None) | (None, Some(_)) => return ConstraintSet::from(false),
+            (Some(_), None) | (None, Some(_)) => return ConstraintSet::from_bool(db, false),
             (None, None) => {}
             (Some(self_tuple), Some(other_tuple)) => {
                 let compatible =

crates/ty_python_semantic/src/types/ide_support.rs

@@ -169,9 +169,9 @@ pub fn definitions_for_name<'db>(
                 // instead of `int` (hover only shows the docstring of the first definition).
                 .rev()
                 .filter_map(|ty| ty.as_nominal_instance())
-                .map(|instance| {
-                    let definition = instance.class_literal(db).definition(db);
-                    ResolvedDefinition::Definition(definition)
+                .filter_map(|instance| {
+                    let definition = instance.class_literal(db).definition(db)?;
+                    Some(ResolvedDefinition::Definition(definition))
                 })
                 .collect();
         }

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

@@ -55,21 +55,22 @@ use crate::subscript::{PyIndex, PySlice};
 use crate::types::call::bind::{CallableDescription, MatchingOverloadIndex};
 use crate::types::call::{Argument, Binding, Bindings, CallArguments, CallError, CallErrorKind};
 use crate::types::class::{
-    ClassLiteral, CodeGeneratorKind, DynamicClassLiteral, DynamicMetaclassConflict, FieldKind,
-    MetaclassErrorKind, MethodDecorator,
+    ClassLiteral, CodeGeneratorKind, DynamicClassAnchor, DynamicClassLiteral,
+    DynamicMetaclassConflict, FieldKind, MetaclassErrorKind, MethodDecorator,
 };
 use crate::types::context::{InNoTypeCheck, InferContext};
 use crate::types::cyclic::CycleDetector;
 use crate::types::diagnostic::{
     self, CALL_NON_CALLABLE, CONFLICTING_DECLARATIONS, CONFLICTING_METACLASS,
     CYCLIC_CLASS_DEFINITION, CYCLIC_TYPE_ALIAS_DEFINITION, DIVISION_BY_ZERO, DUPLICATE_BASE,
-    DUPLICATE_KW_ONLY, INCONSISTENT_MRO, INVALID_ARGUMENT_TYPE, INVALID_ASSIGNMENT,
-    INVALID_ATTRIBUTE_ACCESS, INVALID_BASE, INVALID_DECLARATION, INVALID_GENERIC_CLASS,
-    INVALID_GENERIC_ENUM, INVALID_KEY, INVALID_LEGACY_TYPE_VARIABLE, INVALID_METACLASS,
-    INVALID_NAMED_TUPLE, INVALID_NEWTYPE, INVALID_OVERLOAD, INVALID_PARAMETER_DEFAULT,
-    INVALID_PARAMSPEC, INVALID_PROTOCOL, INVALID_TYPE_ARGUMENTS, INVALID_TYPE_FORM,
-    INVALID_TYPE_GUARD_CALL, INVALID_TYPE_GUARD_DEFINITION, INVALID_TYPE_VARIABLE_CONSTRAINTS,
-    INVALID_TYPED_DICT_STATEMENT, IncompatibleBases, NOT_SUBSCRIPTABLE, POSSIBLY_MISSING_ATTRIBUTE,
+    DUPLICATE_KW_ONLY, INCONSISTENT_MRO, INEFFECTIVE_FINAL, INVALID_ARGUMENT_TYPE,
+    INVALID_ASSIGNMENT, INVALID_ATTRIBUTE_ACCESS, INVALID_BASE, INVALID_DECLARATION,
+    INVALID_GENERIC_CLASS, INVALID_GENERIC_ENUM, INVALID_KEY, INVALID_LEGACY_TYPE_VARIABLE,
+    INVALID_METACLASS, INVALID_NAMED_TUPLE, INVALID_NEWTYPE, INVALID_OVERLOAD,
+    INVALID_PARAMETER_DEFAULT, INVALID_PARAMSPEC, INVALID_PROTOCOL, INVALID_TYPE_ARGUMENTS,
+    INVALID_TYPE_FORM, INVALID_TYPE_GUARD_CALL, INVALID_TYPE_GUARD_DEFINITION,
+    INVALID_TYPE_VARIABLE_CONSTRAINTS, INVALID_TYPED_DICT_STATEMENT, IncompatibleBases,
+    NO_MATCHING_OVERLOAD, NOT_SUBSCRIPTABLE, POSSIBLY_MISSING_ATTRIBUTE,
     POSSIBLY_MISSING_IMPLICIT_CALL, POSSIBLY_MISSING_IMPORT, SUBCLASS_OF_FINAL_CLASS,
     TypedDictDeleteErrorKind, UNDEFINED_REVEAL, UNRESOLVED_ATTRIBUTE, UNRESOLVED_GLOBAL,
     UNRESOLVED_IMPORT, UNRESOLVED_REFERENCE, UNSUPPORTED_DYNAMIC_BASE, UNSUPPORTED_OPERATOR,
@@ -5581,10 +5582,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                             // Try to extract the dynamic class with definition.
                             // This returns `None` if it's not a three-arg call to `type()`,
                             // signalling that we must fall back to normal call inference.
-                            self.infer_dynamic_type_expression(call_expr, definition)
-                                .unwrap_or_else(|| {
-                                    self.infer_call_expression_impl(call_expr, callable_type, tcx)
-                                })
+                            self.infer_builtins_type_call(call_expr, Some(definition))
                         }
                         Some(_) | None => {
                             self.infer_call_expression_impl(call_expr, callable_type, tcx)
@@ -6189,19 +6187,21 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
         }
     }
 
-    /// Try to infer a 3-argument `type(name, bases, dict)` call expression, capturing the definition.
+    /// Infer a call to `builtins.type()`.
     ///
-    /// This is called when we detect a `type()` call in assignment context and want to
-    /// associate the resulting `DynamicClassLiteral` with its definition for go-to-definition.
+    /// `builtins.type` has two overloads: a single-argument overload (e.g. `type("foo")`,
+    /// and a 3-argument `type(name, bases, dict)` overload. Both are handled here.
+    /// The `definition` parameter should be `Some()` if this call to `builtins.type()`
+    /// occurs on the right-hand side of an assignment statement that has a [`Definition`]
+    /// associated with it in the semantic index.
     ///
-    /// Returns `None` if any keywords were provided or the number of arguments is not three,
-    /// signalling that no types were stored for any AST sub-expressions and that we should
-    /// therefore fallback to normal call binding for error reporting.
-    fn infer_dynamic_type_expression(
+    /// If it's unclear which overload we should pick, we return `type[Unknown]`,
+    /// to avoid cascading errors later on.
+    fn infer_builtins_type_call(
         &mut self,
         call_expr: &ast::ExprCall,
-        definition: Definition<'db>,
-    ) -> Option<Type<'db>> {
+        definition: Option<Definition<'db>>,
+    ) -> Type<'db> {
         let db = self.db();
 
         let ast::Arguments {
@@ -6211,27 +6211,101 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
             node_index: _,
         } = &call_expr.arguments;
 
-        if !keywords.is_empty() {
-            return None;
+        for keyword in keywords {
+            self.infer_expression(&keyword.value, TypeContext::default());
         }
 
-        let [name_arg, bases_arg, namespace_arg] = &**args else {
-            return None;
+        let [name_arg, bases_arg, namespace_arg] = match &**args {
+            [single] => {
+                let arg_type = self.infer_expression(single, TypeContext::default());
+
+                return if keywords.is_empty() {
+                    arg_type.dunder_class(db)
+                } else {
+                    if keywords.iter().any(|keyword| keyword.arg.is_some())
+                        && let Some(builder) =
+                            self.context.report_lint(&NO_MATCHING_OVERLOAD, call_expr)
+                    {
+                        let mut diagnostic = builder
+                            .into_diagnostic("No overload of class `type` matches arguments");
+                        diagnostic.help(format_args!(
+                            "`builtins.type()` expects no keyword arguments",
+                        ));
+                    }
+                    SubclassOfType::subclass_of_unknown()
+                };
+            }
+
+            [first, second] if second.is_starred_expr() => {
+                self.infer_expression(first, TypeContext::default());
+                self.infer_expression(second, TypeContext::default());
+
+                match &**keywords {
+                    [single] if single.arg.is_none() => {
+                        return SubclassOfType::subclass_of_unknown();
+                    }
+                    _ => {
+                        if let Some(builder) =
+                            self.context.report_lint(&NO_MATCHING_OVERLOAD, call_expr)
+                        {
+                            let mut diagnostic = builder
+                                .into_diagnostic("No overload of class `type` matches arguments");
+                            diagnostic.help(format_args!(
+                                "`builtins.type()` expects no keyword arguments",
+                            ));
+                        }
+
+                        return SubclassOfType::subclass_of_unknown();
+                    }
+                }
+            }
+
+            [name, bases, namespace] => [name, bases, namespace],
+
+            _ => {
+                for arg in args {
+                    self.infer_expression(arg, TypeContext::default());
+                }
+
+                if let Some(builder) = self.context.report_lint(&NO_MATCHING_OVERLOAD, call_expr) {
+                    let mut diagnostic =
+                        builder.into_diagnostic("No overload of class `type` matches arguments");
+                    diagnostic.help(format_args!(
+                        "`builtins.type()` can either be called with one or three \
+                        positional arguments (got {})",
+                        args.len()
+                    ));
+                }
+
+                return SubclassOfType::subclass_of_unknown();
+            }
         };
 
-        // If any argument is a starred expression, we can't know how many positional arguments
-        // we're receiving, so fall back to normal call binding.
-        if args.iter().any(ast::Expr::is_starred_expr) {
-            return None;
-        }
-
-        // Infer the argument types.
         let name_type = self.infer_expression(name_arg, TypeContext::default());
         let bases_type = self.infer_expression(bases_arg, TypeContext::default());
+        let namespace_type = self.infer_expression(namespace_arg, TypeContext::default());
+
+        // TODO: validate other keywords against `__init_subclass__` methods of superclasses
+        if keywords
+            .iter()
+            .filter_map(|keyword| keyword.arg.as_deref())
+            .contains("metaclass")
+        {
+            if let Some(builder) = self.context.report_lint(&NO_MATCHING_OVERLOAD, call_expr) {
+                let mut diagnostic =
+                    builder.into_diagnostic("No overload of class `type` matches arguments");
+                diagnostic
+                    .help("The `metaclass` keyword argument is not supported in `type()` calls");
+            }
+        }
+
+        // If any argument is a starred expression, we can't know how many positional arguments
+        // we're receiving, so fall back to `type[Unknown]` to avoid false-positive errors.
+        if args.iter().any(ast::Expr::is_starred_expr) {
+            return SubclassOfType::subclass_of_unknown();
+        }
 
         // Extract members from the namespace dict (third argument).
-        // Infer the whole dict first to avoid double-inferring individual values.
-        let namespace_type = self.infer_expression(namespace_arg, TypeContext::default());
         let (members, has_dynamic_namespace): (Box<[(ast::name::Name, Type<'db>)]>, bool) =
             if let ast::Expr::Dict(dict) = namespace_arg {
                 // Check if all keys are string literal types. If any key is not a string literal
@@ -6258,7 +6332,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     .collect();
                 (members, !all_keys_are_string_literals)
             } else if let Type::TypedDict(typed_dict) = namespace_type {
-                // Namespace is a TypedDict instance. Extract known keys as members.
+                // `namespace` is a TypedDict instance. Extract known keys as members.
                 // TypedDicts are "open" (can have additional string keys), so this
                 // is still a dynamic namespace for unknown attributes.
                 let members: Box<[(ast::name::Name, Type<'db>)]> = typed_dict
@@ -6268,7 +6342,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     .collect();
                 (members, true)
             } else {
-                // Namespace is not a dict literal, so it's dynamic.
+                // `namespace` is not a dict literal, so it's dynamic.
                 (Box::new([]), true)
             };
 
@@ -6310,11 +6384,33 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
         let (bases, mut disjoint_bases) =
             self.extract_dynamic_type_bases(bases_arg, bases_type, &name);
 
+        let scope = self.scope();
+
+        // Create the anchor for identifying this dynamic class.
+        // - For assigned `type()` calls, the Definition uniquely identifies the class.
+        // - For dangling calls, compute a relative offset from the scope's node index.
+        let anchor = if let Some(def) = definition {
+            DynamicClassAnchor::Definition(def)
+        } else {
+            let call_node_index = call_expr.node_index().load();
+            let scope_anchor = scope.node(db).node_index().unwrap_or(NodeIndex::from(0));
+            let anchor_u32 = scope_anchor
+                .as_u32()
+                .expect("scope anchor should not be NodeIndex::NONE");
+            let call_u32 = call_node_index
+                .as_u32()
+                .expect("call node should not be NodeIndex::NONE");
+            DynamicClassAnchor::ScopeOffset {
+                scope,
+                offset: call_u32 - anchor_u32,
+            }
+        };
+
         let dynamic_class = DynamicClassLiteral::new(
             db,
             name,
             bases,
-            definition,
+            anchor,
             members,
             has_dynamic_namespace,
             None,
@@ -6384,7 +6480,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
             );
         }
 
-        Some(Type::ClassLiteral(ClassLiteral::Dynamic(dynamic_class)))
+        Type::ClassLiteral(ClassLiteral::Dynamic(dynamic_class))
     }
 
     /// Extract base classes from the second argument of a `type()` call.
@@ -6421,26 +6517,129 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     .iter()
                     .enumerate()
                     .map(|(idx, base)| {
+                        let diagnostic_node = bases_tuple_elts
+                            .and_then(|elts| elts.get(idx))
+                            .unwrap_or(bases_node);
+
                         // First try the standard conversion.
                         if let Some(class_base) =
                             ClassBase::try_from_type(db, *base, placeholder_class)
                         {
-                            // Collect disjoint bases for instance-layout-conflict checking.
-                            if let ClassBase::Class(base_class) = class_base {
-                                if let Some(disjoint_base) = base_class.nearest_disjoint_base(db) {
-                                    disjoint_bases.insert(
-                                        disjoint_base,
-                                        idx,
-                                        base_class.class_literal(db),
-                                    );
+                            // Check for special bases that are not allowed for dynamic classes.
+                            // Dynamic classes can't be generic, protocols, TypedDicts, or enums.
+                            match class_base {
+                                ClassBase::Generic | ClassBase::TypedDict => {
+                                    if let Some(builder) =
+                                        self.context.report_lint(&INVALID_BASE, diagnostic_node)
+                                    {
+                                        let mut diagnostic = builder.into_diagnostic(
+                                            "Invalid base for class created via `type()`",
+                                        );
+                                        diagnostic.set_primary_message(format_args!(
+                                            "Has type `{}`",
+                                            base.display(db)
+                                        ));
+                                        match class_base {
+                                            ClassBase::Generic => {
+                                                diagnostic.info(
+                                                    "Classes created via `type()` cannot be generic",
+                                                );
+                                                diagnostic.info(format_args!(
+                                                    "Consider using `class {name}(Generic[...]): ...` instead"
+                                                ));
+                                            }
+                                            ClassBase::TypedDict => {
+                                                diagnostic.info(
+                                                    "Classes created via `type()` cannot be TypedDicts",
+                                                );
+                                                diagnostic.info(format_args!(
+                                                    "Consider using `TypedDict(\"{name}\", {{}})` instead"
+                                                ));
+                                            }
+                                            _ => unreachable!(),
+                                        }
+                                    }
+                                    return ClassBase::unknown();
                                 }
-                            }
-                            return class_base;
-                        }
+                                ClassBase::Protocol => {
+                                    if let Some(builder) = self
+                                        .context
+                                        .report_lint(&UNSUPPORTED_DYNAMIC_BASE, diagnostic_node)
+                                    {
+                                        let mut diagnostic = builder.into_diagnostic(
+                                            "Unsupported base for class created via `type()`",
+                                        );
+                                        diagnostic.set_primary_message(format_args!(
+                                            "Has type `{}`",
+                                            base.display(db)
+                                        ));
+                                        diagnostic.info(
+                                            "Classes created via `type()` cannot be protocols",
+                                        );
+                                        diagnostic.info(format_args!(
+                                            "Consider using `class {name}(Protocol): ...` instead"
+                                        ));
+                                    }
+                                    return ClassBase::unknown();
+                                }
+                                ClassBase::Class(class_type) => {
+                                    // Check if base is @final (includes enums with members).
+                                    if class_type.is_final(db) {
+                                        if let Some(builder) = self
+                                            .context
+                                            .report_lint(&SUBCLASS_OF_FINAL_CLASS, diagnostic_node)
+                                        {
+                                            builder.into_diagnostic(format_args!(
+                                                "Class `{name}` cannot inherit from final class `{}`",
+                                                class_type.name(db)
+                                            ));
+                                        }
+                                        return ClassBase::unknown();
+                                    }
 
-                        let diagnostic_node = bases_tuple_elts
-                            .and_then(|elts| elts.get(idx))
-                            .unwrap_or(bases_node);
+                                    // Enum subclasses require the EnumMeta metaclass, which
+                                    // expects special dict attributes that `type()` doesn't provide.
+                                    if let Some((static_class, _)) =
+                                        class_type.static_class_literal(db)
+                                    {
+                                        if is_enum_class_by_inheritance(db, static_class) {
+                                            if let Some(builder) = self
+                                                .context
+                                                .report_lint(&INVALID_BASE, diagnostic_node)
+                                            {
+                                                let mut diagnostic = builder.into_diagnostic(
+                                                    "Invalid base for class created via `type()`",
+                                                );
+                                                diagnostic.set_primary_message(format_args!(
+                                                    "Has type `{}`",
+                                                    base.display(db)
+                                                ));
+                                                diagnostic.info(
+                                                    "Creating an enum class via `type()` is not supported",
+                                                );
+                                                diagnostic.info(format_args!(
+                                                    "Consider using `Enum(\"{name}\", [])` instead"
+                                                ));
+                                            }
+                                            return ClassBase::unknown();
+                                        }
+                                    }
+
+                                    // Collect disjoint bases for instance-layout-conflict checking.
+                                    if let Some(disjoint_base) = class_type.nearest_disjoint_base(db)
+                                    {
+                                        disjoint_bases.insert(
+                                            disjoint_base,
+                                            idx,
+                                            class_type.class_literal(db),
+                                        );
+                                    }
+
+                                    return class_base;
+                                }
+                                ClassBase::Dynamic(_) => return class_base,
+                            }
+                        }
 
                         // If that fails, check if the type is "type-like" (e.g., `type[Base]`).
                         // For type-like bases we emit `unsupported-dynamic-base` and use
@@ -9514,6 +9713,13 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
             return Type::TypedDict(typed_dict);
         }
 
+        // Handle 3-argument `type(name, bases, dict)`.
+        if let Type::ClassLiteral(class) = callable_type
+            && class.is_known(self.db(), KnownClass::Type)
+        {
+            return self.infer_builtins_type_call(call_expression, None);
+        }
+
         // We don't call `Type::try_call`, because we want to perform type inference on the
         // arguments after matching them to parameters, but before checking that the argument types
         // are assignable to any parameter annotations.
@@ -9605,6 +9811,20 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
             {
                 self.called_functions.insert(function);
             }
+
+            // Warn when `final()` is called as a function (not a decorator).
+            // Type checkers cannot interpret this usage and will not prevent subclassing.
+            if function.is_known(self.db(), KnownFunction::Final) {
+                if let Some(builder) = self
+                    .context
+                    .report_lint(&INEFFECTIVE_FINAL, call_expression)
+                {
+                    let mut diagnostic = builder.into_diagnostic(
+                        "Type checkers will not prevent subclassing when `final()` is called as a function",
+                    );
+                    diagnostic.info("Use `@final` as a decorator on a class or method instead");
+                }
+            }
         }
 
         let class = match callable_type {
@@ -13321,36 +13541,16 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
         let value_node = subscript.value.as_ref();
 
         let inferred = match (value_ty, slice_ty) {
-            (Type::Dynamic(_) | Type::Never, _) => Some(value_ty),
-
-            (Type::TypeAlias(alias), _) => Some(self.infer_subscript_expression_types(
-                subscript,
-                alias.value_type(self.db()),
-                slice_ty,
-                expr_context,
-            )),
-
-            (_, Type::TypeAlias(alias)) => Some(self.infer_subscript_expression_types(
-                subscript,
-                value_ty,
-                alias.value_type(self.db()),
-                expr_context,
-            )),
-
             (Type::Union(union), _) => Some(union.map(db, |element| {
                 self.infer_subscript_expression_types(subscript, *element, slice_ty, expr_context)
             })),
 
-            (_, Type::Union(union)) => Some(union.map(db, |element| {
-                self.infer_subscript_expression_types(subscript, value_ty, *element, expr_context)
-            })),
-
             // TODO: we can map over the intersection and fold the results back into an intersection,
             // but we need to make sure we avoid emitting a diagnostic if one positive element has a `__getitem__`
             // method but another does not. This means `infer_subscript_expression_types`
             // needs to return a `Result` rather than eagerly emitting diagnostics.
-            (Type::Intersection(_), _) | (_, Type::Intersection(_)) => {
-                Some(todo_type!("Subscript expressions with intersections"))
+            (Type::Intersection(_), _) => {
+                Some(todo_type!("Subscript expressions on intersections"))
             }
 
             // Ex) Given `("a", "b", "c", "d")[1]`, return `"b"`
@@ -13430,16 +13630,6 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                     }
                 }),
 
-            (Type::LiteralString, Type::IntLiteral(_) | Type::BooleanLiteral(_)) => {
-                Some(Type::LiteralString)
-            }
-
-            (Type::LiteralString, Type::NominalInstance(nominal))
-                if nominal.slice_literal(db).is_some() =>
-            {
-                Some(Type::LiteralString)
-            }
-
             // Ex) Given `b"value"[1]`, return `97` (i.e., `ord(b"a")`)
             (Type::BytesLiteral(literal_ty), Type::IntLiteral(i64_int)) => {
                 i32::try_from(i64_int).ok().map(|i32_int| {
@@ -13571,39 +13761,7 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
                 Some(todo_type!("Inference of subscript on special form"))
             }
 
-            (
-                Type::FunctionLiteral(_)
-                | Type::WrapperDescriptor(_)
-                | Type::BoundMethod(_)
-                | Type::DataclassDecorator(_)
-                | Type::DataclassTransformer(_)
-                | Type::Callable(_)
-                | Type::ModuleLiteral(_)
-                | Type::ClassLiteral(_)
-                | Type::GenericAlias(_)
-                | Type::SubclassOf(_)
-                | Type::AlwaysFalsy
-                | Type::AlwaysTruthy
-                | Type::IntLiteral(_)
-                | Type::BooleanLiteral(_)
-                | Type::ProtocolInstance(_)
-                | Type::PropertyInstance(_)
-                | Type::EnumLiteral(_)
-                | Type::BoundSuper(_)
-                | Type::TypeIs(_)
-                | Type::TypeGuard(_)
-                | Type::TypedDict(_)
-                | Type::NewTypeInstance(_)
-                | Type::NominalInstance(_)
-                | Type::SpecialForm(_)
-                | Type::KnownInstance(_)
-                | Type::StringLiteral(_)
-                | Type::BytesLiteral(_)
-                | Type::LiteralString
-                | Type::TypeVar(_)  // TODO: more complex logic required here!
-                | Type::KnownBoundMethod(_),
-                _,
-            ) => None,
+            _ => None,
         };
 
         if let Some(inferred) = inferred {

crates/ty_python_semantic/src/types/instance.rs

@@ -13,6 +13,7 @@ use crate::types::generics::{InferableTypeVars, walk_specialization};
 use crate::types::protocol_class::{ProtocolClass, walk_protocol_interface};
 use crate::types::relation::{
     HasRelationToVisitor, IsDisjointVisitor, IsEquivalentVisitor, TypeRelation,
+    default_disjoint_visitor, default_relation_visitor,
 };
 use crate::types::tuple::{TupleSpec, TupleType, walk_tuple_type};
 use crate::types::{
@@ -179,7 +180,7 @@ impl<'db> Type<'db> {
         // recognise `str` as a subtype of `Container[str]`.
         structurally_satisfied.or(db, || {
             let Some(nominal_instance) = protocol.to_nominal_instance() else {
-                return ConstraintSet::from(false);
+                return ConstraintSet::from_bool(db, false);
             };
 
             // if `self` and `other` are *both* protocols, we also need to treat `self` as if it
@@ -411,7 +412,7 @@ impl<'db> NominalInstanceType<'db> {
         disjointness_visitor: &IsDisjointVisitor<'db>,
     ) -> ConstraintSet<'db> {
         match (self.0, other.0) {
-            (_, NominalInstanceInner::Object) => ConstraintSet::from(true),
+            (_, NominalInstanceInner::Object) => ConstraintSet::from_bool(db, true),
             (
                 NominalInstanceInner::ExactTuple(tuple1),
                 NominalInstanceInner::ExactTuple(tuple2),
@@ -447,12 +448,12 @@ impl<'db> NominalInstanceType<'db> {
                 NominalInstanceInner::ExactTuple(tuple2),
             ) => tuple1.is_equivalent_to_impl(db, tuple2, inferable, visitor),
             (NominalInstanceInner::Object, NominalInstanceInner::Object) => {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
             (NominalInstanceInner::NonTuple(class1), NominalInstanceInner::NonTuple(class2)) => {
                 class1.is_equivalent_to_impl(db, class2, inferable, visitor)
             }
-            _ => ConstraintSet::from(false),
+            _ => ConstraintSet::from_bool(db, false),
         }
     }
 
@@ -465,9 +466,9 @@ impl<'db> NominalInstanceType<'db> {
         relation_visitor: &HasRelationToVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self.is_object() || other.is_object() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
-        let mut result = ConstraintSet::from(false);
+        let mut result = ConstraintSet::from_bool(db, false);
         if let Some(self_spec) = self.tuple_spec(db) {
             if let Some(other_spec) = other.tuple_spec(db) {
                 let compatible = self_spec.is_disjoint_from_impl(
@@ -484,7 +485,8 @@ impl<'db> NominalInstanceType<'db> {
         }
 
         result.or(db, || {
-            ConstraintSet::from(
+            ConstraintSet::from_bool(
+                db,
                 !self
                     .class(db)
                     .could_coexist_in_mro_with(db, other.class(db)),
@@ -713,8 +715,8 @@ impl<'db> ProtocolInstanceType<'db> {
                     protocol,
                     InferableTypeVars::None,
                     TypeRelation::Subtyping,
-                    &HasRelationToVisitor::default(),
-                    &IsDisjointVisitor::default(),
+                    &default_relation_visitor(db),
+                    &default_disjoint_visitor(db),
                 )
                 .is_always_satisfied(db)
         }
@@ -780,13 +782,13 @@ impl<'db> ProtocolInstanceType<'db> {
         _visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
         let self_normalized = self.normalized(db);
         if self_normalized == Type::ProtocolInstance(other) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
-        ConstraintSet::from(self_normalized == other.normalized(db))
+        ConstraintSet::from_bool(db, self_normalized == other.normalized(db))
     }
 
     /// Return `true` if this protocol type is disjoint from the protocol `other`.
@@ -796,12 +798,12 @@ impl<'db> ProtocolInstanceType<'db> {
     #[expect(clippy::unused_self)]
     pub(super) fn is_disjoint_from_impl(
         self,
-        _db: &'db dyn Db,
+        db: &'db dyn Db,
         _other: Self,
         _inferable: InferableTypeVars<'_, 'db>,
         _visitor: &IsDisjointVisitor<'db>,
     ) -> ConstraintSet<'db> {
-        ConstraintSet::from(false)
+        ConstraintSet::from_bool(db, false)
     }
 
     pub(crate) fn instance_member(self, db: &'db dyn Db, name: &str) -> PlaceAndQualifiers<'db> {

crates/ty_python_semantic/src/types/newtype.rs

@@ -125,16 +125,16 @@ impl<'db> NewType<'db> {
     // base class, we don't have to keep looking.
     pub(crate) fn has_relation_to_impl(self, db: &'db dyn Db, other: Self) -> ConstraintSet<'db> {
         if self.is_equivalent_to_impl(db, other) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
         for base in self.iter_bases(db) {
             if let NewTypeBase::NewType(base_newtype) = base {
                 if base_newtype.is_equivalent_to_impl(db, other) {
-                    return ConstraintSet::from(true);
+                    return ConstraintSet::from_bool(db, true);
                 }
             }
         }
-        ConstraintSet::from(false)
+        ConstraintSet::from_bool(db, false)
     }
 
     pub(crate) fn is_disjoint_from_impl(self, db: &'db dyn Db, other: Self) -> ConstraintSet<'db> {

crates/ty_python_semantic/src/types/protocol_class.rs

@@ -292,76 +292,44 @@ impl<'db> ProtocolInterface<'db> {
     ) -> ConstraintSet<'db> {
         other.members(db).when_all(db, |other_member| {
             self.member_by_name(db, other_member.name)
-                .when_some_and(|our_member| match (our_member.kind, other_member.kind) {
-                    // Method members are always immutable;
-                    // they can never be subtypes of/assignable to mutable attribute members.
-                    (ProtocolMemberKind::Method(_), ProtocolMemberKind::Other(_)) => {
-                        ConstraintSet::from(false)
-                    }
+                .when_some_and(db, |our_member| {
+                    match (our_member.kind, other_member.kind) {
+                        // Method members are always immutable;
+                        // they can never be subtypes of/assignable to mutable attribute members.
+                        (ProtocolMemberKind::Method(_), ProtocolMemberKind::Other(_)) => {
+                            ConstraintSet::from_bool(db, false)
+                        }
 
-                    // A property member can only be a subtype of an attribute member
-                    // if the property is readable *and* writable.
-                    //
-                    // TODO: this should also consider the types of the members on both sides.
-                    (ProtocolMemberKind::Property(property), ProtocolMemberKind::Other(_)) => {
-                        ConstraintSet::from(
-                            property.getter(db).is_some() && property.setter(db).is_some(),
-                        )
-                    }
+                        // A property member can only be a subtype of an attribute member
+                        // if the property is readable *and* writable.
+                        //
+                        // TODO: this should also consider the types of the members on both sides.
+                        (ProtocolMemberKind::Property(property), ProtocolMemberKind::Other(_)) => {
+                            ConstraintSet::from_bool(
+                                db,
+                                property.getter(db).is_some() && property.setter(db).is_some(),
+                            )
+                        }
 
-                    // A `@property` member can never be a subtype of a method member, as it is not necessarily
-                    // accessible on the meta-type, whereas a method member must be.
-                    (ProtocolMemberKind::Property(_), ProtocolMemberKind::Method(_)) => {
-                        ConstraintSet::from(false)
-                    }
+                        // A `@property` member can never be a subtype of a method member, as it is not necessarily
+                        // accessible on the meta-type, whereas a method member must be.
+                        (ProtocolMemberKind::Property(_), ProtocolMemberKind::Method(_)) => {
+                            ConstraintSet::from_bool(db, false)
+                        }
 
-                    // But an attribute member *can* be a subtype of a method member,
-                    // providing it is marked `ClassVar`
-                    (
-                        ProtocolMemberKind::Other(our_type),
-                        ProtocolMemberKind::Method(other_type),
-                    ) => ConstraintSet::from(
-                        our_member.qualifiers.contains(TypeQualifiers::CLASS_VAR),
-                    )
-                    .and(db, || {
-                        our_type.has_relation_to_impl(
+                        // But an attribute member *can* be a subtype of a method member,
+                        // providing it is marked `ClassVar`
+                        (
+                            ProtocolMemberKind::Other(our_type),
+                            ProtocolMemberKind::Method(other_type),
+                        ) => ConstraintSet::from_bool(
                             db,
-                            Type::Callable(protocol_bind_self(db, other_type, None)),
-                            inferable,
-                            relation,
-                            relation_visitor,
-                            disjointness_visitor,
-                        )
-                    }),
-
-                    (
-                        ProtocolMemberKind::Method(our_method),
-                        ProtocolMemberKind::Method(other_method),
-                    ) => our_method.bind_self(db, None).has_relation_to_impl(
-                        db,
-                        protocol_bind_self(db, other_method, None),
-                        inferable,
-                        relation,
-                        relation_visitor,
-                        disjointness_visitor,
-                    ),
-
-                    (
-                        ProtocolMemberKind::Other(our_type),
-                        ProtocolMemberKind::Other(other_type),
-                    ) => our_type
-                        .has_relation_to_impl(
-                            db,
-                            other_type,
-                            inferable,
-                            relation,
-                            relation_visitor,
-                            disjointness_visitor,
+                            our_member.qualifiers.contains(TypeQualifiers::CLASS_VAR),
                         )
                         .and(db, || {
-                            other_type.has_relation_to_impl(
+                            our_type.has_relation_to_impl(
                                 db,
-                                our_type,
+                                Type::Callable(protocol_bind_self(db, other_type, None)),
                                 inferable,
                                 relation,
                                 relation_visitor,
@@ -369,14 +337,50 @@ impl<'db> ProtocolInterface<'db> {
                             )
                         }),
 
-                    // TODO: finish assignability/subtyping between two `@property` members,
-                    // and between a `@property` member and a member of a different kind.
-                    (
-                        ProtocolMemberKind::Property(_)
-                        | ProtocolMemberKind::Method(_)
-                        | ProtocolMemberKind::Other(_),
-                        ProtocolMemberKind::Property(_),
-                    ) => ConstraintSet::from(true),
+                        (
+                            ProtocolMemberKind::Method(our_method),
+                            ProtocolMemberKind::Method(other_method),
+                        ) => our_method.bind_self(db, None).has_relation_to_impl(
+                            db,
+                            protocol_bind_self(db, other_method, None),
+                            inferable,
+                            relation,
+                            relation_visitor,
+                            disjointness_visitor,
+                        ),
+
+                        (
+                            ProtocolMemberKind::Other(our_type),
+                            ProtocolMemberKind::Other(other_type),
+                        ) => our_type
+                            .has_relation_to_impl(
+                                db,
+                                other_type,
+                                inferable,
+                                relation,
+                                relation_visitor,
+                                disjointness_visitor,
+                            )
+                            .and(db, || {
+                                other_type.has_relation_to_impl(
+                                    db,
+                                    our_type,
+                                    inferable,
+                                    relation,
+                                    relation_visitor,
+                                    disjointness_visitor,
+                                )
+                            }),
+
+                        // TODO: finish assignability/subtyping between two `@property` members,
+                        // and between a `@property` member and a member of a different kind.
+                        (
+                            ProtocolMemberKind::Property(_)
+                            | ProtocolMemberKind::Method(_)
+                            | ProtocolMemberKind::Other(_),
+                            ProtocolMemberKind::Property(_),
+                        ) => ConstraintSet::from_bool(db, true),
+                    }
                 })
         })
     }
@@ -713,7 +717,7 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
         match &self.kind {
             // TODO: implement disjointness for property/method members as well as attribute members
             ProtocolMemberKind::Property(_) | ProtocolMemberKind::Method(_) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
             ProtocolMemberKind::Other(ty) => ty.is_disjoint_from_impl(
                 db,
@@ -764,7 +768,7 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
                         )
                         .place
                     else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     attribute_type
                 };
@@ -783,7 +787,7 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
                 let fallback_other = other.literal_fallback_instance(db).unwrap_or(other);
                 attribute_type
                     .try_upcast_to_callable(db)
-                    .when_some_and(|callables| {
+                    .when_some_and(db, |callables| {
                         callables
                             .map(|callable| callable.apply_self(db, fallback_other))
                             .has_relation_to_impl(
@@ -797,13 +801,16 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
                     })
             }
             // TODO: consider the types of the attribute on `other` for property members
-            ProtocolMemberKind::Property(_) => ConstraintSet::from(matches!(
-                other.member(db, self.name).place,
-                Place::Defined(DefinedPlace {
-                    definedness: Definedness::AlwaysDefined,
-                    ..
-                })
-            )),
+            ProtocolMemberKind::Property(_) => ConstraintSet::from_bool(
+                db,
+                matches!(
+                    other.member(db, self.name).place,
+                    Place::Defined(DefinedPlace {
+                        definedness: Definedness::AlwaysDefined,
+                        ..
+                    })
+                ),
+            ),
             ProtocolMemberKind::Other(member_type) => {
                 let Place::Defined(DefinedPlace {
                     ty: attribute_type,
@@ -811,7 +818,7 @@ impl<'a, 'db> ProtocolMember<'a, 'db> {
                     ..
                 }) = other.member(db, self.name).place
                 else {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 };
                 member_type
                     .has_relation_to_impl(

crates/ty_python_semantic/src/types/relation.rs

@@ -310,8 +310,8 @@ impl<'db> Type<'db> {
             target,
             inferable,
             relation,
-            &HasRelationToVisitor::default(),
-            &IsDisjointVisitor::default(),
+            &default_relation_visitor(db),
+            &default_disjoint_visitor(db),
         )
     }
 
@@ -330,7 +330,7 @@ impl<'db> Type<'db> {
         // Note that we could do a full equivalence check here, but that would be both expensive
         // and unnecessary. This early return is only an optimisation.
         if (!relation.is_subtyping() || self.subtyping_is_always_reflexive()) && self == target {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         // Handle constraint implication first. If either `self` or `target` is a typevar, check
@@ -359,22 +359,22 @@ impl<'db> Type<'db> {
         match (self, target) {
             // Everything is a subtype of `object`.
             (_, Type::NominalInstance(instance)) if instance.is_object() => {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
             (_, Type::ProtocolInstance(target)) if target.is_equivalent_to_object(db) => {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             // `Never` is the bottom type, the empty set.
             // It is a subtype of all other types.
-            (Type::Never, _) => ConstraintSet::from(true),
+            (Type::Never, _) => ConstraintSet::from_bool(db, true),
 
             // In some specific situations, `Any`/`Unknown`/`@Todo` can be simplified out of unions and intersections,
             // but this is not true for divergent types (and moving this case any lower down appears to cause
             // "too many cycle iterations" panics).
             (Type::Dynamic(DynamicType::Divergent(_)), _)
             | (_, Type::Dynamic(DynamicType::Divergent(_))) => {
-                ConstraintSet::from(relation.is_assignability())
+                ConstraintSet::from_bool(db, relation.is_assignability())
             }
 
             (Type::TypeAlias(self_alias), _) => {
@@ -409,7 +409,7 @@ impl<'db> Type<'db> {
             (Type::KnownInstance(KnownInstanceType::Field(field)), right)
                 if relation.is_assignability() =>
             {
-                field.default_type(db).when_none_or(|default_type| {
+                field.default_type(db).when_none_or(db, |default_type| {
                     default_type.has_relation_to_impl(
                         db,
                         right,
@@ -434,31 +434,39 @@ impl<'db> Type<'db> {
                     !matches!(dynamic, DynamicType::Divergent(_)),
                     "DynamicType::Divergent should have been handled in an earlier branch"
                 );
-                ConstraintSet::from(match relation {
+                ConstraintSet::from_bool(
+                    db,
+                    match relation {
+                        TypeRelation::Subtyping | TypeRelation::SubtypingAssuming(_) => false,
+                        TypeRelation::Assignability | TypeRelation::ConstraintSetAssignability => {
+                            true
+                        }
+                        TypeRelation::Redundancy => match target {
+                            Type::Dynamic(_) => true,
+                            Type::Union(union) => union.elements(db).iter().any(Type::is_dynamic),
+                            _ => false,
+                        },
+                    },
+                )
+            }
+            (_, Type::Dynamic(_)) => ConstraintSet::from_bool(
+                db,
+                match relation {
                     TypeRelation::Subtyping | TypeRelation::SubtypingAssuming(_) => false,
                     TypeRelation::Assignability | TypeRelation::ConstraintSetAssignability => true,
-                    TypeRelation::Redundancy => match target {
+                    TypeRelation::Redundancy => match self {
                         Type::Dynamic(_) => true,
-                        Type::Union(union) => union.elements(db).iter().any(Type::is_dynamic),
+                        Type::Intersection(intersection) => {
+                            // If a `Divergent` type is involved, it must not be eliminated.
+                            intersection
+                                .positive(db)
+                                .iter()
+                                .any(Type::is_non_divergent_dynamic)
+                        }
                         _ => false,
                     },
-                })
-            }
-            (_, Type::Dynamic(_)) => ConstraintSet::from(match relation {
-                TypeRelation::Subtyping | TypeRelation::SubtypingAssuming(_) => false,
-                TypeRelation::Assignability | TypeRelation::ConstraintSetAssignability => true,
-                TypeRelation::Redundancy => match self {
-                    Type::Dynamic(_) => true,
-                    Type::Intersection(intersection) => {
-                        // If a `Divergent` type is involved, it must not be eliminated.
-                        intersection
-                            .positive(db)
-                            .iter()
-                            .any(Type::is_non_divergent_dynamic)
-                    }
-                    _ => false,
                 },
-            }),
+            ),
 
             // In general, a TypeVar `T` is not a subtype of a type `S` unless one of the two conditions is satisfied:
             // 1. `T` is a bound TypeVar and `T`'s upper bound is a subtype of `S`.
@@ -471,7 +479,7 @@ impl<'db> Type<'db> {
                 if !bound_typevar.is_inferable(db, inferable)
                     && union.elements(db).contains(&self) =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             // A similar rule applies in reverse to intersection types.
@@ -479,13 +487,13 @@ impl<'db> Type<'db> {
                 if !bound_typevar.is_inferable(db, inferable)
                     && intersection.positive(db).contains(&target) =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
             (Type::Intersection(intersection), Type::TypeVar(bound_typevar))
                 if !bound_typevar.is_inferable(db, inferable)
                     && intersection.negative(db).contains(&target) =>
             {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             // Two identical typevars must always solve to the same type, so they are always
@@ -497,7 +505,7 @@ impl<'db> Type<'db> {
                 if !lhs_bound_typevar.is_inferable(db, inferable)
                     && lhs_bound_typevar.is_same_typevar_as(db, rhs_bound_typevar) =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             // `type[T]` is a subtype of the class object `A` if every instance of `T` is a subtype of an instance
@@ -506,7 +514,7 @@ impl<'db> Type<'db> {
                 if !subclass_of
                     .into_type_var()
                     .zip(target.to_instance(db))
-                    .when_some_and(|(this_instance, other_instance)| {
+                    .when_some_and(db, |(this_instance, other_instance)| {
                         Type::TypeVar(this_instance).has_relation_to_impl(
                             db,
                             other_instance,
@@ -522,7 +530,7 @@ impl<'db> Type<'db> {
                 subclass_of
                     .into_type_var()
                     .zip(target.to_instance(db))
-                    .when_some_and(|(this_instance, other_instance)| {
+                    .when_some_and(db, |(this_instance, other_instance)| {
                         Type::TypeVar(this_instance).has_relation_to_impl(
                             db,
                             other_instance,
@@ -538,7 +546,7 @@ impl<'db> Type<'db> {
                 if !subclass_of
                     .into_type_var()
                     .zip(self.to_instance(db))
-                    .when_some_and(|(other_instance, this_instance)| {
+                    .when_some_and(db, |(other_instance, this_instance)| {
                         this_instance.has_relation_to_impl(
                             db,
                             Type::TypeVar(other_instance),
@@ -554,7 +562,7 @@ impl<'db> Type<'db> {
                 subclass_of
                     .into_type_var()
                     .zip(self.to_instance(db))
-                    .when_some_and(|(other_instance, this_instance)| {
+                    .when_some_and(db, |(other_instance, this_instance)| {
                         this_instance.has_relation_to_impl(
                             db,
                             Type::TypeVar(other_instance),
@@ -607,7 +615,7 @@ impl<'db> Type<'db> {
                     && !bound_typevar
                         .typevar(db)
                         .constraints(db)
-                        .when_some_and(|constraints| {
+                        .when_some_and(db, |constraints| {
                             constraints.iter().when_all(db, |constraint| {
                                 self.has_relation_to_impl(
                                     db,
@@ -628,7 +636,7 @@ impl<'db> Type<'db> {
                 bound_typevar
                     .typevar(db)
                     .constraints(db)
-                    .when_some_and(|constraints| {
+                    .when_some_and(db, |constraints| {
                         constraints.iter().when_all(db, |constraint| {
                             self.has_relation_to_impl(
                                 db,
@@ -648,11 +656,11 @@ impl<'db> Type<'db> {
 
                 // TODO: record the unification constraints
 
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             // `Never` is the bottom type, the empty set.
-            (_, Type::Never) => ConstraintSet::from(false),
+            (_, Type::Never) => ConstraintSet::from_bool(db, false),
 
             (Type::NewTypeInstance(self_newtype), Type::NewTypeInstance(target_newtype)) => {
                 self_newtype.has_relation_to_impl(db, target_newtype)
@@ -711,7 +719,7 @@ impl<'db> Type<'db> {
                                 disjointness_visitor,
                             )
                         } else {
-                            ConstraintSet::from(false)
+                            ConstraintSet::from_bool(db, false)
                         }
                     })
             }
@@ -815,7 +823,7 @@ impl<'db> Type<'db> {
             // bound. This is true even if the bound is a final class, since the typevar can still
             // be specialized to `Never`.)
             (_, Type::TypeVar(bound_typevar)) if !bound_typevar.is_inferable(db, inferable) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             (_, Type::TypeVar(typevar))
@@ -836,26 +844,29 @@ impl<'db> Type<'db> {
             {
                 // TODO: record the unification constraints
 
-                typevar.typevar(db).upper_bound(db).when_none_or(|bound| {
-                    self.has_relation_to_impl(
-                        db,
-                        bound,
-                        inferable,
-                        relation,
-                        relation_visitor,
-                        disjointness_visitor,
-                    )
-                })
+                typevar
+                    .typevar(db)
+                    .upper_bound(db)
+                    .when_none_or(db, |bound| {
+                        self.has_relation_to_impl(
+                            db,
+                            bound,
+                            inferable,
+                            relation,
+                            relation_visitor,
+                            disjointness_visitor,
+                        )
+                    })
             }
 
             // TODO: Infer specializations here
             (_, Type::TypeVar(bound_typevar)) if bound_typevar.is_inferable(db, inferable) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
             (Type::TypeVar(bound_typevar), _) => {
                 // All inferable cases should have been handled above
                 assert!(!bound_typevar.is_inferable(db, inferable));
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             // All other `NewType` assignments fall back to the concrete base type.
@@ -875,8 +886,12 @@ impl<'db> Type<'db> {
 
             // Note that the definition of `Type::AlwaysFalsy` depends on the return value of `__bool__`.
             // If `__bool__` always returns True or False, it can be treated as a subtype of `AlwaysTruthy` or `AlwaysFalsy`, respectively.
-            (left, Type::AlwaysFalsy) => ConstraintSet::from(left.bool(db).is_always_false()),
-            (left, Type::AlwaysTruthy) => ConstraintSet::from(left.bool(db).is_always_true()),
+            (left, Type::AlwaysFalsy) => {
+                ConstraintSet::from_bool(db, left.bool(db).is_always_false())
+            }
+            (left, Type::AlwaysTruthy) => {
+                ConstraintSet::from_bool(db, left.bool(db).is_always_true())
+            }
             // Currently, the only supertype of `AlwaysFalsy` and `AlwaysTruthy` is the universal set (object instance).
             (Type::AlwaysFalsy | Type::AlwaysTruthy, _) => {
                 target.when_equivalent_to(db, Type::object(), inferable)
@@ -936,7 +951,7 @@ impl<'db> Type<'db> {
                 | Type::FunctionLiteral(_)
                 | Type::ModuleLiteral(_)
                 | Type::EnumLiteral(_),
-            ) => ConstraintSet::from(false),
+            ) => ConstraintSet::from_bool(db, false),
 
             (Type::Callable(self_callable), Type::Callable(other_callable)) => relation_visitor
                 .visit((self, target, relation), || {
@@ -952,16 +967,17 @@ impl<'db> Type<'db> {
 
             (_, Type::Callable(other_callable)) => {
                 relation_visitor.visit((self, target, relation), || {
-                    self.try_upcast_to_callable(db).when_some_and(|callables| {
-                        callables.has_relation_to_impl(
-                            db,
-                            other_callable,
-                            inferable,
-                            relation,
-                            relation_visitor,
-                            disjointness_visitor,
-                        )
-                    })
+                    self.try_upcast_to_callable(db)
+                        .when_some_and(db, |callables| {
+                            callables.has_relation_to_impl(
+                                db,
+                                other_callable,
+                                inferable,
+                                relation,
+                                relation_visitor,
+                                disjointness_visitor,
+                            )
+                        })
                 })
             }
 
@@ -999,7 +1015,7 @@ impl<'db> Type<'db> {
             }
 
             // A protocol instance can never be a subtype of a nominal type, with the *sole* exception of `object`.
-            (Type::ProtocolInstance(_), _) => ConstraintSet::from(false),
+            (Type::ProtocolInstance(_), _) => ConstraintSet::from_bool(db, false),
 
             (Type::TypedDict(self_typeddict), Type::TypedDict(other_typeddict)) => relation_visitor
                 .visit((self, target, relation), || {
@@ -1031,22 +1047,22 @@ impl<'db> Type<'db> {
             }),
 
             // A non-`TypedDict` cannot subtype a `TypedDict`
-            (_, Type::TypedDict(_)) => ConstraintSet::from(false),
+            (_, Type::TypedDict(_)) => ConstraintSet::from_bool(db, false),
 
             // All `StringLiteral` types are a subtype of `LiteralString`.
-            (Type::StringLiteral(_), Type::LiteralString) => ConstraintSet::from(true),
+            (Type::StringLiteral(_), Type::LiteralString) => ConstraintSet::from_bool(db, true),
 
             // An instance is a subtype of an enum literal, if it is an instance of the enum class
             // and the enum has only one member.
             (Type::NominalInstance(_), Type::EnumLiteral(target_enum_literal)) => {
                 if target_enum_literal.enum_class_instance(db) != self {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
 
-                ConstraintSet::from(is_single_member_enum(
+                ConstraintSet::from_bool(
                     db,
-                    target_enum_literal.enum_class(db),
-                ))
+                    is_single_member_enum(db, target_enum_literal.enum_class(db)),
+                )
             }
 
             // Except for the special `LiteralString` case above,
@@ -1062,7 +1078,7 @@ impl<'db> Type<'db> {
                 | Type::EnumLiteral(_)
                 | Type::FunctionLiteral(_),
                 _,
-            ) => (self.literal_fallback_instance(db)).when_some_and(|instance| {
+            ) => (self.literal_fallback_instance(db)).when_some_and(db, |instance| {
                 instance.has_relation_to_impl(
                     db,
                     target,
@@ -1107,7 +1123,7 @@ impl<'db> Type<'db> {
 
             (Type::DataclassDecorator(_) | Type::DataclassTransformer(_), _) => {
                 // TODO: Implement subtyping using an equivalent `Callable` type.
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             // `TypeIs` is invariant.
@@ -1170,7 +1186,7 @@ impl<'db> Type<'db> {
                     )
             }
 
-            (Type::Callable(_), _) => ConstraintSet::from(false),
+            (Type::Callable(_), _) => ConstraintSet::from_bool(db, false),
 
             (Type::BoundSuper(_), Type::BoundSuper(_)) => {
                 self.when_equivalent_to(db, target, inferable)
@@ -1187,7 +1203,7 @@ impl<'db> Type<'db> {
             (Type::SubclassOf(subclass_of), _) | (_, Type::SubclassOf(subclass_of))
                 if subclass_of.is_type_var() =>
             {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             // `Literal[<class 'C'>]` is a subtype of `type[B]` if `C` is a subclass of `B`,
@@ -1205,7 +1221,7 @@ impl<'db> Type<'db> {
                         disjointness_visitor,
                     )
                 })
-                .unwrap_or_else(|| ConstraintSet::from(relation.is_assignability())),
+                .unwrap_or_else(|| ConstraintSet::from_bool(db, relation.is_assignability())),
 
             // Similarly, `<class 'C'>` is assignable to `<class 'C[...]'>` (a generic-alias type)
             // if the default specialization of `C` is assignable to `C[...]`. This scenario occurs
@@ -1247,7 +1263,7 @@ impl<'db> Type<'db> {
                         disjointness_visitor,
                     )
                 })
-                .unwrap_or_else(|| ConstraintSet::from(relation.is_assignability())),
+                .unwrap_or_else(|| ConstraintSet::from_bool(db, relation.is_assignability())),
 
             // This branch asks: given two types `type[T]` and `type[S]`, is `type[T]` a subtype of `type[S]`?
             (Type::SubclassOf(self_subclass_ty), Type::SubclassOf(target_subclass_ty)) => {
@@ -1298,7 +1314,7 @@ impl<'db> Type<'db> {
                         disjointness_visitor,
                     )
                     .or(db, || {
-                        ConstraintSet::from(relation.is_assignability()).and(db, || {
+                        ConstraintSet::from_bool(db, relation.is_assignability()).and(db, || {
                             other.has_relation_to_impl(
                                 db,
                                 KnownClass::Type.to_instance(db),
@@ -1403,7 +1419,7 @@ impl<'db> Type<'db> {
 
             // Other than the special cases enumerated above, nominal-instance types are never
             // subtypes of any other variants
-            (Type::NominalInstance(_), _) => ConstraintSet::from(false),
+            (Type::NominalInstance(_), _) => ConstraintSet::from_bool(db, false),
         }
     }
 
@@ -1430,7 +1446,7 @@ impl<'db> Type<'db> {
         other: Type<'db>,
         inferable: InferableTypeVars<'_, 'db>,
     ) -> ConstraintSet<'db> {
-        self.is_equivalent_to_impl(db, other, inferable, &IsEquivalentVisitor::default())
+        self.is_equivalent_to_impl(db, other, inferable, &default_equivalent_visitor(db))
     }
 
     pub(crate) fn is_equivalent_to_impl(
@@ -1441,7 +1457,7 @@ impl<'db> Type<'db> {
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
         if self == other {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         match (self, other) {
@@ -1449,17 +1465,17 @@ impl<'db> Type<'db> {
             // which prevents `Divergent` from being eliminated during union reduction.
             (Type::Dynamic(_), Type::Dynamic(DynamicType::Divergent(_)))
             | (Type::Dynamic(DynamicType::Divergent(_)), Type::Dynamic(_)) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
-            (Type::Dynamic(_), Type::Dynamic(_)) => ConstraintSet::from(true),
+            (Type::Dynamic(_), Type::Dynamic(_)) => ConstraintSet::from_bool(db, true),
 
             (Type::SubclassOf(first), Type::SubclassOf(second)) => {
                 match (first.subclass_of(), second.subclass_of()) {
-                    (first, second) if first == second => ConstraintSet::from(true),
+                    (first, second) if first == second => ConstraintSet::from_bool(db, true),
                     (SubclassOfInner::Dynamic(_), SubclassOfInner::Dynamic(_)) => {
-                        ConstraintSet::from(true)
+                        ConstraintSet::from_bool(db, true)
                     }
-                    _ => ConstraintSet::from(false),
+                    _ => ConstraintSet::from_bool(db, false),
                 }
             }
 
@@ -1478,7 +1494,7 @@ impl<'db> Type<'db> {
             }
 
             (Type::NewTypeInstance(self_newtype), Type::NewTypeInstance(other_newtype)) => {
-                ConstraintSet::from(self_newtype.is_equivalent_to_impl(db, other_newtype))
+                ConstraintSet::from_bool(db, self_newtype.is_equivalent_to_impl(db, other_newtype))
             }
 
             (Type::NominalInstance(first), Type::NominalInstance(second)) => {
@@ -1511,16 +1527,16 @@ impl<'db> Type<'db> {
             }
             (Type::ProtocolInstance(protocol), nominal @ Type::NominalInstance(n))
             | (nominal @ Type::NominalInstance(n), Type::ProtocolInstance(protocol)) => {
-                ConstraintSet::from(n.is_object() && protocol.normalized(db) == nominal)
+                ConstraintSet::from_bool(db, n.is_object() && protocol.normalized(db) == nominal)
             }
             // An instance of an enum class is equivalent to an enum literal of that class,
             // if that enum has only has one member.
             (Type::NominalInstance(instance), Type::EnumLiteral(literal))
             | (Type::EnumLiteral(literal), Type::NominalInstance(instance)) => {
                 if literal.enum_class_instance(db) != Type::NominalInstance(instance) {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
-                ConstraintSet::from(is_single_member_enum(db, instance.class_literal(db)))
+                ConstraintSet::from_bool(db, is_single_member_enum(db, instance.class_literal(db)))
             }
 
             (Type::PropertyInstance(left), Type::PropertyInstance(right)) => {
@@ -1531,7 +1547,7 @@ impl<'db> Type<'db> {
                 left.is_equivalent_to_impl(db, right, inferable, visitor)
             }),
 
-            _ => ConstraintSet::from(false),
+            _ => ConstraintSet::from_bool(db, false),
         }
     }
 
@@ -1565,8 +1581,8 @@ impl<'db> Type<'db> {
             db,
             other,
             inferable,
-            &IsDisjointVisitor::default(),
-            &HasRelationToVisitor::default(),
+            &default_disjoint_visitor(db),
+            &default_relation_visitor(db),
         )
     }
 
@@ -1591,7 +1607,7 @@ impl<'db> Type<'db> {
                     .member(db, member.name())
                     .place
                     .ignore_possibly_undefined()
-                    .when_none_or(|attribute_type| {
+                    .when_none_or(db, |attribute_type| {
                         member.has_disjoint_type_from(
                             db,
                             attribute_type,
@@ -1604,9 +1620,9 @@ impl<'db> Type<'db> {
         }
 
         match (self, other) {
-            (Type::Never, _) | (_, Type::Never) => ConstraintSet::from(true),
+            (Type::Never, _) | (_, Type::Never) => ConstraintSet::from_bool(db, true),
 
-            (Type::Dynamic(_), _) | (_, Type::Dynamic(_)) => ConstraintSet::from(false),
+            (Type::Dynamic(_), _) | (_, Type::Dynamic(_)) => ConstraintSet::from_bool(db, false),
 
             (Type::TypeAlias(alias), _) => {
                 let self_alias_ty = alias.value_type(db);
@@ -1659,7 +1675,7 @@ impl<'db> Type<'db> {
                 if !subclass_of
                     .into_type_var()
                     .zip(other.to_instance(db))
-                    .when_none_or(|(this_instance, other_instance)| {
+                    .when_none_or(db, |(this_instance, other_instance)| {
                         Type::TypeVar(this_instance).is_disjoint_from_impl(
                             db,
                             other_instance,
@@ -1674,7 +1690,7 @@ impl<'db> Type<'db> {
                 subclass_of
                     .into_type_var()
                     .zip(other.to_instance(db))
-                    .when_none_or(|(this_instance, other_instance)| {
+                    .when_none_or(db, |(this_instance, other_instance)| {
                         Type::TypeVar(this_instance).is_disjoint_from_impl(
                             db,
                             other_instance,
@@ -1693,7 +1709,7 @@ impl<'db> Type<'db> {
                 if !self_bound_typevar.is_inferable(db, inferable)
                     && self_bound_typevar.is_same_typevar_as(db, other_bound_typevar) =>
             {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             (tvar @ Type::TypeVar(bound_typevar), Type::Intersection(intersection))
@@ -1701,7 +1717,7 @@ impl<'db> Type<'db> {
                 if !bound_typevar.is_inferable(db, inferable)
                     && intersection.negative(db).contains(&tvar) =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             // An unbounded typevar is never disjoint from any other type, since it might be
@@ -1712,7 +1728,7 @@ impl<'db> Type<'db> {
                 if !bound_typevar.is_inferable(db, inferable) =>
             {
                 match bound_typevar.typevar(db).bound_or_constraints(db) {
-                    None => ConstraintSet::from(false),
+                    None => ConstraintSet::from_bool(db, false),
                     Some(TypeVarBoundOrConstraints::UpperBound(bound)) => bound
                         .is_disjoint_from_impl(
                             db,
@@ -1736,7 +1752,7 @@ impl<'db> Type<'db> {
             }
 
             // TODO: Infer specializations here
-            (Type::TypeVar(_), _) | (_, Type::TypeVar(_)) => ConstraintSet::from(false),
+            (Type::TypeVar(_), _) | (_, Type::TypeVar(_)) => ConstraintSet::from_bool(db, false),
 
             (Type::Union(union), other) | (other, Type::Union(union)) => {
                 union.elements(db).iter().when_all(db, |e| {
@@ -1841,7 +1857,7 @@ impl<'db> Type<'db> {
                 | Type::ClassLiteral(..)
                 | Type::SpecialForm(..)
                 | Type::KnownInstance(..)),
-            ) => ConstraintSet::from(left != right),
+            ) => ConstraintSet::from_bool(db, left != right),
 
             (
                 Type::SubclassOf(_),
@@ -1870,16 +1886,16 @@ impl<'db> Type<'db> {
                 | Type::WrapperDescriptor(..)
                 | Type::ModuleLiteral(..),
                 Type::SubclassOf(_),
-            ) => ConstraintSet::from(true),
+            ) => ConstraintSet::from_bool(db, true),
 
             (Type::AlwaysTruthy, ty) | (ty, Type::AlwaysTruthy) => {
                 // `Truthiness::Ambiguous` may include `AlwaysTrue` as a subset, so it's not guaranteed to be disjoint.
                 // Thus, they are only disjoint if `ty.bool() == AlwaysFalse`.
-                ConstraintSet::from(ty.bool(db).is_always_false())
+                ConstraintSet::from_bool(db, ty.bool(db).is_always_false())
             }
             (Type::AlwaysFalsy, ty) | (ty, Type::AlwaysFalsy) => {
                 // Similarly, they are only disjoint if `ty.bool() == AlwaysTrue`.
-                ConstraintSet::from(ty.bool(db).is_always_true())
+                ConstraintSet::from_bool(db, ty.bool(db).is_always_true())
             }
 
             (Type::ProtocolInstance(left), Type::ProtocolInstance(right)) => disjointness_visitor
@@ -2011,7 +2027,7 @@ impl<'db> Type<'db> {
                                 disjointness_visitor,
                                 relation_visitor,
                             ),
-                            Place::Undefined => ConstraintSet::from(false),
+                            Place::Undefined => ConstraintSet::from_bool(db, false),
                         }
                     })
                 })
@@ -2020,26 +2036,29 @@ impl<'db> Type<'db> {
             (Type::SubclassOf(subclass_of_ty), _) | (_, Type::SubclassOf(subclass_of_ty))
                 if subclass_of_ty.is_type_var() =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             (Type::GenericAlias(left_alias), Type::GenericAlias(right_alias)) => {
-                ConstraintSet::from(left_alias.origin(db) != right_alias.origin(db)).or(db, || {
-                    left_alias.specialization(db).is_disjoint_from_impl(
-                        db,
-                        right_alias.specialization(db),
-                        inferable,
-                        disjointness_visitor,
-                        relation_visitor,
-                    )
-                })
+                ConstraintSet::from_bool(db, left_alias.origin(db) != right_alias.origin(db)).or(
+                    db,
+                    || {
+                        left_alias.specialization(db).is_disjoint_from_impl(
+                            db,
+                            right_alias.specialization(db),
+                            inferable,
+                            disjointness_visitor,
+                            relation_visitor,
+                        )
+                    },
+                )
             }
 
             (Type::ClassLiteral(class_literal), other @ Type::GenericAlias(_))
             | (other @ Type::GenericAlias(_), Type::ClassLiteral(class_literal)) => class_literal
                 .default_specialization(db)
                 .into_generic_alias()
-                .when_none_or(|alias| {
+                .when_none_or(db, |alias| {
                     other.is_disjoint_from_impl(
                         db,
                         Type::GenericAlias(alias),
@@ -2052,8 +2071,9 @@ impl<'db> Type<'db> {
             (Type::SubclassOf(subclass_of_ty), Type::ClassLiteral(class_b))
             | (Type::ClassLiteral(class_b), Type::SubclassOf(subclass_of_ty)) => {
                 match subclass_of_ty.subclass_of() {
-                    SubclassOfInner::Dynamic(_) => ConstraintSet::from(false),
-                    SubclassOfInner::Class(class_a) => ConstraintSet::from(
+                    SubclassOfInner::Dynamic(_) => ConstraintSet::from_bool(db, false),
+                    SubclassOfInner::Class(class_a) => ConstraintSet::from_bool(
+                        db,
                         !class_a.could_exist_in_mro_of(db, ClassType::NonGeneric(class_b)),
                     ),
                     SubclassOfInner::TypeVar(_) => unreachable!(),
@@ -2063,8 +2083,9 @@ impl<'db> Type<'db> {
             (Type::SubclassOf(subclass_of_ty), Type::GenericAlias(alias_b))
             | (Type::GenericAlias(alias_b), Type::SubclassOf(subclass_of_ty)) => {
                 match subclass_of_ty.subclass_of() {
-                    SubclassOfInner::Dynamic(_) => ConstraintSet::from(false),
-                    SubclassOfInner::Class(class_a) => ConstraintSet::from(
+                    SubclassOfInner::Dynamic(_) => ConstraintSet::from_bool(db, false),
+                    SubclassOfInner::Class(class_a) => ConstraintSet::from_bool(
+                        db,
                         !class_a.could_exist_in_mro_of(db, ClassType::Generic(alias_b)),
                     ),
                     SubclassOfInner::TypeVar(_) => unreachable!(),
@@ -2102,12 +2123,12 @@ impl<'db> Type<'db> {
 
             (Type::SpecialForm(special_form), Type::NominalInstance(instance))
             | (Type::NominalInstance(instance), Type::SpecialForm(special_form)) => {
-                ConstraintSet::from(!special_form.is_instance_of(db, instance.class(db)))
+                ConstraintSet::from_bool(db, !special_form.is_instance_of(db, instance.class(db)))
             }
 
             (Type::KnownInstance(known_instance), Type::NominalInstance(instance))
             | (Type::NominalInstance(instance), Type::KnownInstance(known_instance)) => {
-                ConstraintSet::from(!known_instance.is_instance_of(db, instance.class(db)))
+                ConstraintSet::from_bool(db, !known_instance.is_instance_of(db, instance.class(db)))
             }
 
             (
@@ -2127,7 +2148,7 @@ impl<'db> Type<'db> {
 
             (Type::BooleanLiteral(..) | Type::TypeIs(_) | Type::TypeGuard(_), _)
             | (_, Type::BooleanLiteral(..) | Type::TypeIs(_) | Type::TypeGuard(_)) => {
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             (Type::IntLiteral(..), Type::NominalInstance(instance))
@@ -2139,10 +2160,12 @@ impl<'db> Type<'db> {
                     .negate(db)
             }
 
-            (Type::IntLiteral(..), _) | (_, Type::IntLiteral(..)) => ConstraintSet::from(true),
+            (Type::IntLiteral(..), _) | (_, Type::IntLiteral(..)) => {
+                ConstraintSet::from_bool(db, true)
+            }
 
             (Type::StringLiteral(..), Type::LiteralString)
-            | (Type::LiteralString, Type::StringLiteral(..)) => ConstraintSet::from(false),
+            | (Type::LiteralString, Type::StringLiteral(..)) => ConstraintSet::from_bool(db, false),
 
             (Type::StringLiteral(..) | Type::LiteralString, Type::NominalInstance(instance))
             | (Type::NominalInstance(instance), Type::StringLiteral(..) | Type::LiteralString) => {
@@ -2153,8 +2176,10 @@ impl<'db> Type<'db> {
                     .negate(db)
             }
 
-            (Type::LiteralString, Type::LiteralString) => ConstraintSet::from(false),
-            (Type::LiteralString, _) | (_, Type::LiteralString) => ConstraintSet::from(true),
+            (Type::LiteralString, Type::LiteralString) => ConstraintSet::from_bool(db, false),
+            (Type::LiteralString, _) | (_, Type::LiteralString) => {
+                ConstraintSet::from_bool(db, true)
+            }
 
             (Type::BytesLiteral(..), Type::NominalInstance(instance))
             | (Type::NominalInstance(instance), Type::BytesLiteral(..)) => {
@@ -2179,7 +2204,9 @@ impl<'db> Type<'db> {
                     )
                     .negate(db)
             }
-            (Type::EnumLiteral(..), _) | (_, Type::EnumLiteral(..)) => ConstraintSet::from(true),
+            (Type::EnumLiteral(..), _) | (_, Type::EnumLiteral(..)) => {
+                ConstraintSet::from_bool(db, true)
+            }
 
             // A class-literal type `X` is always disjoint from an instance type `Y`,
             // unless the type expressing "all instances of `Z`" is a subtype of of `Y`,
@@ -2250,7 +2277,7 @@ impl<'db> Type<'db> {
                 // No two callable types are ever disjoint because
                 // `(*args: object, **kwargs: object) -> Never` is a subtype of all fully static
                 // callable types.
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             (Type::Callable(_), Type::StringLiteral(_) | Type::BytesLiteral(_))
@@ -2258,7 +2285,7 @@ impl<'db> Type<'db> {
                 // A callable type is disjoint from other literal types. For example,
                 // `Type::StringLiteral` must be an instance of exactly `str`, not a subclass
                 // of `str`, and `str` is not callable. The same applies to other literal types.
-                ConstraintSet::from(true)
+                ConstraintSet::from_bool(db, true)
             }
 
             (Type::Callable(_), Type::SpecialForm(special_form))
@@ -2267,7 +2294,7 @@ impl<'db> Type<'db> {
                 // that are callable (like TypedDict and collection constructors).
                 // Most special forms are type constructors/annotations (like `typing.Literal`,
                 // `typing.Union`, etc.) that are subscripted, not called.
-                ConstraintSet::from(!special_form.is_callable())
+                ConstraintSet::from_bool(db, !special_form.is_callable())
             }
 
             (
@@ -2285,7 +2312,7 @@ impl<'db> Type<'db> {
                 )
                 .place
                 .ignore_possibly_undefined()
-                .when_none_or(|dunder_call| {
+                .when_none_or(db, |dunder_call| {
                     dunder_call
                         .has_relation_to_impl(
                             db,
@@ -2307,7 +2334,7 @@ impl<'db> Type<'db> {
                 Type::Callable(_) | Type::DataclassDecorator(_) | Type::DataclassTransformer(_),
             ) => {
                 // TODO: Implement disjointness for general callable type with other types
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
 
             (Type::ModuleLiteral(..), other @ Type::NominalInstance(..))
@@ -2369,7 +2396,9 @@ impl<'db> Type<'db> {
                 )
             }
 
-            (Type::GenericAlias(_), _) | (_, Type::GenericAlias(_)) => ConstraintSet::from(true),
+            (Type::GenericAlias(_), _) | (_, Type::GenericAlias(_)) => {
+                ConstraintSet::from_bool(db, true)
+            }
 
             (Type::TypedDict(self_typeddict), Type::TypedDict(other_typeddict)) => {
                 disjointness_visitor.visit((self, other), || {
@@ -2416,10 +2445,8 @@ fn is_redundant_with_cycle_initial<'db>(
 pub(crate) type HasRelationToVisitor<'db> =
     CycleDetector<TypeRelation<'db>, (Type<'db>, Type<'db>, TypeRelation<'db>), ConstraintSet<'db>>;
 
-impl Default for HasRelationToVisitor<'_> {
-    fn default() -> Self {
-        HasRelationToVisitor::new(ConstraintSet::from(true))
-    }
+pub(crate) fn default_relation_visitor(db: &dyn Db) -> HasRelationToVisitor<'_> {
+    HasRelationToVisitor::new(ConstraintSet::from_bool(db, true))
 }
 
 /// A [`PairVisitor`] that is used in `is_disjoint_from` methods.
@@ -2428,10 +2455,8 @@ pub(crate) type IsDisjointVisitor<'db> = PairVisitor<'db, IsDisjoint, Constraint
 #[derive(Debug)]
 pub(crate) struct IsDisjoint;
 
-impl Default for IsDisjointVisitor<'_> {
-    fn default() -> Self {
-        IsDisjointVisitor::new(ConstraintSet::from(false))
-    }
+pub(crate) fn default_disjoint_visitor(db: &dyn Db) -> IsDisjointVisitor<'_> {
+    IsDisjointVisitor::new(ConstraintSet::from_bool(db, false))
 }
 
 /// A [`PairVisitor`] that is used in `is_equivalent` methods.
@@ -2440,8 +2465,6 @@ pub(crate) type IsEquivalentVisitor<'db> = PairVisitor<'db, IsEquivalent, Constr
 #[derive(Debug)]
 pub(crate) struct IsEquivalent;
 
-impl Default for IsEquivalentVisitor<'_> {
-    fn default() -> Self {
-        IsEquivalentVisitor::new(ConstraintSet::from(true))
-    }
+pub(crate) fn default_equivalent_visitor(db: &dyn Db) -> IsEquivalentVisitor<'_> {
+    IsEquivalentVisitor::new(ConstraintSet::from_bool(db, true))
 }

crates/ty_python_semantic/src/types/signatures.rs

@@ -23,6 +23,7 @@ use crate::types::generics::{GenericContext, InferableTypeVars, walk_generic_con
 use crate::types::infer::{infer_deferred_types, infer_scope_types};
 use crate::types::relation::{
     HasRelationToVisitor, IsDisjointVisitor, IsEquivalentVisitor, TypeRelation,
+    default_disjoint_visitor, default_relation_visitor,
 };
 use crate::types::{
     ApplyTypeMappingVisitor, BindingContext, BoundTypeVarInstance, CallableType, CallableTypeKind,
@@ -306,8 +307,8 @@ impl<'db> CallableSignature<'db> {
             other,
             inferable,
             TypeRelation::Subtyping,
-            &HasRelationToVisitor::default(),
-            &IsDisjointVisitor::default(),
+            &default_relation_visitor(db),
+            &default_disjoint_visitor(db),
         )
     }
 
@@ -362,8 +363,8 @@ impl<'db> CallableSignature<'db> {
             other,
             inferable,
             TypeRelation::ConstraintSetAssignability,
-            &HasRelationToVisitor::default(),
-            &IsDisjointVisitor::default(),
+            &default_relation_visitor(db),
+            &default_disjoint_visitor(db),
         )
     }
 
@@ -549,7 +550,7 @@ impl<'db> CallableSignature<'db> {
             }
             (_, _) => {
                 if self == other {
-                    return ConstraintSet::from(true);
+                    return ConstraintSet::from_bool(db, true);
                 }
                 self.is_subtype_of_impl(db, other, inferable)
                     .and(db, || other.is_subtype_of_impl(db, self, inferable))
@@ -1005,14 +1006,14 @@ impl<'db> Signature<'db> {
         inferable: InferableTypeVars<'_, 'db>,
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
-        let mut result = ConstraintSet::from(true);
+        let mut result = ConstraintSet::from_bool(db, true);
 
         if self.parameters.is_gradual() != other.parameters.is_gradual() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         if self.parameters.len() != other.parameters.len() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         let mut check_types = |self_type: Type<'db>, other_type: Type<'db>| {
@@ -1069,7 +1070,7 @@ impl<'db> Signature<'db> {
 
                 (ParameterKind::KeywordVariadic { .. }, ParameterKind::KeywordVariadic { .. }) => {}
 
-                _ => return ConstraintSet::from(false),
+                _ => return ConstraintSet::from_bool(db, false),
             }
 
             if !check_types(
@@ -1132,8 +1133,8 @@ impl<'db> Signature<'db> {
             other,
             inferable,
             TypeRelation::ConstraintSetAssignability,
-            &HasRelationToVisitor::default(),
-            &IsDisjointVisitor::default(),
+            &default_relation_visitor(db),
+            &default_disjoint_visitor(db),
         )
     }
 
@@ -1251,7 +1252,7 @@ impl<'db> Signature<'db> {
             }
         }
 
-        let mut result = ConstraintSet::from(true);
+        let mut result = ConstraintSet::from_bool(db, true);
 
         let mut check_types = |type1: Type<'db>, type2: Type<'db>| {
             match (type1, type2) {
@@ -1308,15 +1309,15 @@ impl<'db> Signature<'db> {
                 .keyword_variadic()
                 .is_some_and(|(_, param)| param.annotated_type().is_object())
         {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         // The top signature is supertype of (and assignable from) all other signatures. It is a
         // subtype of no signature except itself, and assignable only to the gradual signature.
         if other.parameters.is_top() {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         } else if self.parameters.is_top() && !other.parameters.is_gradual() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
 
         // If either of the parameter lists is gradual (`...`), then it is assignable to and from
@@ -1324,7 +1325,8 @@ impl<'db> Signature<'db> {
         if self.parameters.is_gradual() || other.parameters.is_gradual() {
             result.intersect(
                 db,
-                ConstraintSet::from(
+                ConstraintSet::from_bool(
+                    db,
                     relation.is_assignability() || relation.is_constraint_set_assignability(),
                 ),
             );
@@ -1426,7 +1428,7 @@ impl<'db> Signature<'db> {
                         // `other`, then the non-variadic parameters in `self` must have a default
                         // value.
                         if default_type.is_none() {
-                            return ConstraintSet::from(false);
+                            return ConstraintSet::from_bool(db, false);
                         }
                     }
                     ParameterKind::Variadic { .. } | ParameterKind::KeywordVariadic { .. } => {
@@ -1438,7 +1440,7 @@ impl<'db> Signature<'db> {
                 EitherOrBoth::Right(_) => {
                     // If there are more parameters in `other` than in `self`, then `self` is not a
                     // subtype of `other`.
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
 
                 EitherOrBoth::Both(self_parameter, other_parameter) => {
@@ -1458,7 +1460,7 @@ impl<'db> Signature<'db> {
                             },
                         ) => {
                             if self_default.is_none() && other_default.is_some() {
-                                return ConstraintSet::from(false);
+                                return ConstraintSet::from_bool(db, false);
                             }
                             if !check_types(
                                 other_parameter.annotated_type(),
@@ -1479,11 +1481,11 @@ impl<'db> Signature<'db> {
                             },
                         ) => {
                             if self_name != other_name {
-                                return ConstraintSet::from(false);
+                                return ConstraintSet::from_bool(db, false);
                             }
                             // The following checks are the same as positional-only parameters.
                             if self_default.is_none() && other_default.is_some() {
-                                return ConstraintSet::from(false);
+                                return ConstraintSet::from_bool(db, false);
                             }
                             if !check_types(
                                 other_parameter.annotated_type(),
@@ -1568,7 +1570,7 @@ impl<'db> Signature<'db> {
                             break;
                         }
 
-                        _ => return ConstraintSet::from(false),
+                        _ => return ConstraintSet::from_bool(db, false),
                     }
                 }
             }
@@ -1601,7 +1603,7 @@ impl<'db> Signature<'db> {
                     // previous loop. They cannot be matched against any parameter in `other` which
                     // only contains keyword-only and keyword-variadic parameters so the subtype
                     // relation is invalid.
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
                 ParameterKind::Variadic { .. } => {}
             }
@@ -1628,7 +1630,7 @@ impl<'db> Signature<'db> {
                                 ..
                             } => {
                                 if self_default.is_none() && other_default.is_some() {
-                                    return ConstraintSet::from(false);
+                                    return ConstraintSet::from_bool(db, false);
                                 }
                                 if !check_types(
                                     other_parameter.annotated_type(),
@@ -1649,14 +1651,14 @@ impl<'db> Signature<'db> {
                             return result;
                         }
                     } else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     }
                 }
                 ParameterKind::KeywordVariadic { .. } => {
                     let Some(self_keyword_variadic_type) = self_keyword_variadic else {
                         // For a `self <: other` relationship, if `other` has a keyword variadic
                         // parameter, `self` must also have a keyword variadic parameter.
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     if !check_types(other_parameter.annotated_type(), self_keyword_variadic_type) {
                         return result;
@@ -1664,7 +1666,7 @@ impl<'db> Signature<'db> {
                 }
                 _ => {
                     // This can only occur in case of a syntax error.
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
             }
         }
@@ -1673,7 +1675,7 @@ impl<'db> Signature<'db> {
         // optional otherwise the subtype relation is invalid.
         for (_, self_parameter) in self_keywords {
             if self_parameter.default_type().is_none() {
-                return ConstraintSet::from(false);
+                return ConstraintSet::from_bool(db, false);
             }
         }
 

crates/ty_python_semantic/src/types/subclass_of.rs

@@ -224,13 +224,16 @@ impl<'db> SubclassOfType<'db> {
     ) -> ConstraintSet<'db> {
         match (self.subclass_of, other.subclass_of) {
             (SubclassOfInner::Dynamic(_), SubclassOfInner::Dynamic(_)) => {
-                ConstraintSet::from(!relation.is_subtyping())
+                ConstraintSet::from_bool(db, !relation.is_subtyping())
             }
             (SubclassOfInner::Dynamic(_), SubclassOfInner::Class(other_class)) => {
-                ConstraintSet::from(other_class.is_object(db) || relation.is_assignability())
+                ConstraintSet::from_bool(
+                    db,
+                    other_class.is_object(db) || relation.is_assignability(),
+                )
             }
             (SubclassOfInner::Class(_), SubclassOfInner::Dynamic(_)) => {
-                ConstraintSet::from(relation.is_assignability())
+                ConstraintSet::from_bool(db, relation.is_assignability())
             }
 
             // For example, `type[bool]` describes all possible runtime subclasses of the class `bool`,
@@ -264,10 +267,10 @@ impl<'db> SubclassOfType<'db> {
     ) -> ConstraintSet<'db> {
         match (self.subclass_of, other.subclass_of) {
             (SubclassOfInner::Dynamic(_), _) | (_, SubclassOfInner::Dynamic(_)) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
             (SubclassOfInner::Class(self_class), SubclassOfInner::Class(other_class)) => {
-                ConstraintSet::from(!self_class.could_coexist_in_mro_with(db, other_class))
+                ConstraintSet::from_bool(db, !self_class.could_coexist_in_mro_with(db, other_class))
             }
             (SubclassOfInner::TypeVar(_), _) | (_, SubclassOfInner::TypeVar(_)) => {
                 unreachable!()

crates/ty_python_semantic/src/types/tuple.rs

@@ -516,7 +516,7 @@ impl<'db> FixedLengthTuple<Type<'db>> {
     ) -> ConstraintSet<'db> {
         match other {
             Tuple::Fixed(other) => {
-                ConstraintSet::from(self.0.len() == other.0.len()).and(db, || {
+                ConstraintSet::from_bool(db, self.0.len() == other.0.len()).and(db, || {
                     (self.0.iter().zip(&other.0)).when_all(db, |(self_ty, other_ty)| {
                         self_ty.has_relation_to_impl(
                             db,
@@ -533,11 +533,11 @@ impl<'db> FixedLengthTuple<Type<'db>> {
             Tuple::Variable(other) => {
                 // This tuple must have enough elements to match up with the other tuple's prefix
                 // and suffix, and each of those elements must pairwise satisfy the relation.
-                let mut result = ConstraintSet::from(true);
+                let mut result = ConstraintSet::from_bool(db, true);
                 let mut self_iter = self.0.iter();
                 for other_ty in other.prefix_elements() {
                     let Some(self_ty) = self_iter.next() else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     let element_constraints = self_ty.has_relation_to_impl(
                         db,
@@ -556,7 +556,7 @@ impl<'db> FixedLengthTuple<Type<'db>> {
                 }
                 for other_ty in other.iter_suffix_elements().rev() {
                     let Some(self_ty) = self_iter.next_back() else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     let element_constraints = self_ty.has_relation_to_impl(
                         db,
@@ -599,7 +599,7 @@ impl<'db> FixedLengthTuple<Type<'db>> {
         inferable: InferableTypeVars<'_, 'db>,
         visitor: &IsEquivalentVisitor<'db>,
     ) -> ConstraintSet<'db> {
-        ConstraintSet::from(self.0.len() == other.0.len()).and(db, || {
+        ConstraintSet::from_bool(db, self.0.len() == other.0.len()).and(db, || {
             (self.0.iter())
                 .zip(&other.0)
                 .when_all(db, |(self_ty, other_ty)| {
@@ -1031,17 +1031,17 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                 // possible lengths. This means that `tuple[Any, ...]` can match any tuple of any
                 // length.
                 if !relation.is_assignability() || !self.variable().is_dynamic() {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
 
                 // In addition, the other tuple must have enough elements to match up with this
                 // tuple's prefix and suffix, and each of those elements must pairwise satisfy the
                 // relation.
-                let mut result = ConstraintSet::from(true);
+                let mut result = ConstraintSet::from_bool(db, true);
                 let mut other_iter = other.iter_all_elements();
                 for self_ty in self.prenormalized_prefix_elements(db, None) {
                     let Some(other_ty) = other_iter.next() else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     let element_constraints = self_ty.has_relation_to_impl(
                         db,
@@ -1061,7 +1061,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                 let suffix: Vec<_> = self.prenormalized_suffix_elements(db, None).collect();
                 for self_ty in suffix.iter().rev() {
                     let Some(other_ty) = other_iter.next_back() else {
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     };
                     let element_constraints = self_ty.has_relation_to_impl(
                         db,
@@ -1097,7 +1097,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                 // The overlapping parts of the prefixes and suffixes must satisfy the relation.
                 // Any remaining parts must satisfy the relation with the other tuple's
                 // variable-length part.
-                let mut result = ConstraintSet::from(true);
+                let mut result = ConstraintSet::from_bool(db, true);
                 let pairwise = self
                     .prenormalized_prefix_elements(db, self_prenormalize_variable)
                     .zip_longest(
@@ -1127,7 +1127,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                             // that can materialize to provide it (for assignability only),
                             // as in `tuple[Any, ...]` matching `tuple[int, int]`.
                             if !relation.is_assignability() || !self.variable().is_dynamic() {
-                                return ConstraintSet::from(false);
+                                return ConstraintSet::from_bool(db, false);
                             }
                             self.variable().has_relation_to_impl(
                                 db,
@@ -1181,7 +1181,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                             // that can materialize to provide it (for assignability only),
                             // as in `tuple[Any, ...]` matching `tuple[int, int]`.
                             if !relation.is_assignability() || !self.variable().is_dynamic() {
-                                return ConstraintSet::from(false);
+                                return ConstraintSet::from_bool(db, false);
                             }
                             self.variable().has_relation_to_impl(
                                 db,
@@ -1233,7 +1233,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                             self_ty.is_equivalent_to_impl(db, other_ty, inferable, visitor)
                         }
                         EitherOrBoth::Left(_) | EitherOrBoth::Right(_) => {
-                            ConstraintSet::from(false)
+                            ConstraintSet::from_bool(db, false)
                         }
                     })
             })
@@ -1245,7 +1245,7 @@ impl<'db> VariableLengthTuple<Type<'db>> {
                             self_ty.is_equivalent_to_impl(db, other_ty, inferable, visitor)
                         }
                         EitherOrBoth::Left(_) | EitherOrBoth::Right(_) => {
-                            ConstraintSet::from(false)
+                            ConstraintSet::from_bool(db, false)
                         }
                     })
             })
@@ -1513,7 +1513,7 @@ impl<'db> Tuple<Type<'db>> {
                 self_tuple.is_equivalent_to_impl(db, other_tuple, inferable, visitor)
             }
             (Tuple::Fixed(_), Tuple::Variable(_)) | (Tuple::Variable(_), Tuple::Fixed(_)) => {
-                ConstraintSet::from(false)
+                ConstraintSet::from_bool(db, false)
             }
         }
     }
@@ -1530,10 +1530,10 @@ impl<'db> Tuple<Type<'db>> {
         let (self_min, self_max) = self.len().size_hint();
         let (other_min, other_max) = other.len().size_hint();
         if self_max.is_some_and(|max| max < other_min) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
         if other_max.is_some_and(|max| max < self_min) {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         // If any of the required elements are pairwise disjoint, the tuples are disjoint as well.

crates/ty_python_semantic/src/types/typed_dict.rs

@@ -151,24 +151,24 @@ impl<'db> TypedDictType<'db> {
             && let Some(target_defining_class) = target.defining_class()
             && defining_class.is_subclass_of(db, target_defining_class)
         {
-            return ConstraintSet::from(true);
+            return ConstraintSet::from_bool(db, true);
         }
 
         let self_items = self.items(db);
         let target_items = target.items(db);
         // Many rules violations short-circuit with "never", but asking whether one field is
         // [relation] to/of another can produce more complicated constraints, and we collect those.
-        let mut constraints = ConstraintSet::from(true);
+        let mut constraints = ConstraintSet::from_bool(db, true);
         for (target_item_name, target_item_field) in target_items {
             let field_constraints = if target_item_field.is_required() {
                 // required target fields
                 let Some(self_item_field) = self_items.get(target_item_name) else {
                     // Self is missing a required field.
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 };
                 if !self_item_field.is_required() {
                     // A required field is not required in self.
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
                 if target_item_field.is_read_only() {
                     // For `ReadOnly[]` fields in the target, the corresponding fields in
@@ -186,7 +186,7 @@ impl<'db> TypedDictType<'db> {
                 } else {
                     if self_item_field.is_read_only() {
                         // A read-only field can't be assigned to a mutable target.
-                        return ConstraintSet::from(false);
+                        return ConstraintSet::from_bool(db, false);
                     }
                     // For mutable fields in the target, the relation needs to apply both
                     // ways, or else mutating the target could violate the structural
@@ -252,12 +252,12 @@ impl<'db> TypedDictType<'db> {
                     if let Some(self_item_field) = self_items.get(target_item_name) {
                         if self_item_field.is_read_only() {
                             // A read-only field can't be assigned to a mutable target.
-                            return ConstraintSet::from(false);
+                            return ConstraintSet::from_bool(db, false);
                         }
                         if self_item_field.is_required() {
                             // A required field can't be assigned to a not-required, mutable field
                             // in the target, because `del` is allowed on the target field.
-                            return ConstraintSet::from(false);
+                            return ConstraintSet::from_bool(db, false);
                         }
 
                         // As above, for mutable fields in the target, the relation needs
@@ -289,7 +289,7 @@ impl<'db> TypedDictType<'db> {
                         // interaction between two structural assignability rules prevents
                         // unsoundness" in `typed_dict.md`.
                         // TODO: `closed` and `extra_items` support will go here.
-                        ConstraintSet::from(false)
+                        ConstraintSet::from_bool(db, false)
                     }
                 }
             };
@@ -303,14 +303,14 @@ impl<'db> TypedDictType<'db> {
 
     pub fn definition(self, db: &'db dyn Db) -> Option<Definition<'db>> {
         match self {
-            TypedDictType::Class(defining_class) => Some(defining_class.definition(db)),
+            TypedDictType::Class(defining_class) => defining_class.definition(db),
             TypedDictType::Synthesized(_) => None,
         }
     }
 
     pub fn type_definition(self, db: &'db dyn Db) -> Option<TypeDefinition<'db>> {
         match self {
-            TypedDictType::Class(defining_class) => Some(defining_class.type_definition(db)),
+            TypedDictType::Class(defining_class) => defining_class.type_definition(db),
             TypedDictType::Synthesized(_) => None,
         }
     }
@@ -341,13 +341,13 @@ impl<'db> TypedDictType<'db> {
         // sorted order instead of paying for a lookup for each field, as long as their lengths are
         // the same.
         if self.items(db).len() != other.items(db).len() {
-            return ConstraintSet::from(false);
+            return ConstraintSet::from_bool(db, false);
         }
         self.items(db).iter().zip(other.items(db)).when_all(
             db,
             |((name, field), (other_name, other_field))| {
                 if name != other_name || field.flags != other_field.flags {
-                    return ConstraintSet::from(false);
+                    return ConstraintSet::from_bool(db, false);
                 }
                 field.declared_ty.is_equivalent_to_impl(
                     db,
@@ -435,7 +435,7 @@ impl<'db> TypedDictType<'db> {
                 {
                     // One side demands a `Required` source field, while the other side demands a
                     // `NotRequired` one. They must be disjoint.
-                    return ConstraintSet::from(true);
+                    return ConstraintSet::from_bool(db, true);
                 }
             }
             if !self_field.is_read_only() && !other_field.is_read_only() {

ty.schema.json

@@ -520,6 +520,16 @@
             }
           ]
         },
+        "ineffective-final": {
+          "title": "detects calls to `final()` that type checkers cannot interpret",
+          "description": "## What it does\nChecks for calls to `final()` that type checkers cannot interpret.\n\n## Why is this bad?\nThe `final()` function is designed to be used as a decorator. When called directly\nas a function (e.g., `final(type(...))`), type checkers will not understand the\napplication of `final` and will not prevent subclassing.\n\n## Example\n\n```python\nfrom typing import final\n\n# Incorrect: type checkers will not prevent subclassing\nMyClass = final(type(\"MyClass\", (), {}))\n\n# Correct: use `final` as a decorator\n@final\nclass MyClass: ...\n```",
+          "default": "warn",
+          "oneOf": [
+            {
+              "$ref": "#/definitions/Level"
+            }
+          ]
+        },
         "instance-layout-conflict": {
           "title": "detects class definitions that raise `TypeError` due to instance layout conflict",
           "description": "## What it does\nChecks for classes definitions which will fail at runtime due to\n\"instance memory layout conflicts\".\n\nThis error is usually caused by attempting to combine multiple classes\nthat define non-empty `__slots__` in a class's [Method Resolution Order]\n(MRO), or by attempting to combine multiple builtin classes in a class's\nMRO.\n\n## Why is this bad?\nInheriting from bases with conflicting instance memory layouts\nwill lead to a `TypeError` at runtime.\n\nAn instance memory layout conflict occurs when CPython cannot determine\nthe memory layout instances of a class should have, because the instance\nmemory layout of one of its bases conflicts with the instance memory layout\nof one or more of its other bases.\n\nFor example, if a Python class defines non-empty `__slots__`, this will\nimpact the memory layout of instances of that class. Multiple inheritance\nfrom more than one different class defining non-empty `__slots__` is not\nallowed:\n\n```python\nclass A:\n    __slots__ = (\"a\", \"b\")\n\nclass B:\n    __slots__ = (\"a\", \"b\")  # Even if the values are the same\n\n# TypeError: multiple bases have instance lay-out conflict\nclass C(A, B): ...\n```\n\nAn instance layout conflict can also be caused by attempting to use\nmultiple inheritance with two builtin classes, due to the way that these\nclasses are implemented in a CPython C extension:\n\n```python\nclass A(int, float): ...  # TypeError: multiple bases have instance lay-out conflict\n```\n\nNote that pure-Python classes with no `__slots__`, or pure-Python classes\nwith empty `__slots__`, are always compatible:\n\n```python\nclass A: ...\nclass B:\n    __slots__ = ()\nclass C:\n    __slots__ = (\"a\", \"b\")\n\n# fine\nclass D(A, B, C): ...\n```\n\n## Known problems\nClasses that have \"dynamic\" definitions of `__slots__` (definitions do not consist\nof string literals, or tuples of string literals) are not currently considered disjoint\nbases by ty.\n\nAdditionally, this check is not exhaustive: many C extensions (including several in\nthe standard library) define classes that use extended memory layouts and thus cannot\ncoexist in a single MRO. Since it is currently not possible to represent this fact in\nstub files, having a full knowledge of these classes is also impossible. When it comes\nto classes that do not define `__slots__` at the Python level, therefore, ty, currently\nonly hard-codes a number of cases where it knows that a class will produce instances with\nan atypical memory layout.\n\n## Further reading\n- [CPython documentation: `__slots__`](https://docs.python.org/3/reference/datamodel.html#slots)\n- [CPython documentation: Method Resolution Order](https://docs.python.org/3/glossary.html#term-method-resolution-order)\n\n[Method Resolution Order]: https://docs.python.org/3/glossary.html#term-method-resolution-order",