Carl Meyer 4fdb4e8219 [ty] avoid unions of generic aliases of the same class in fixpoint (#21909) ... Partially addresses https://github.com/astral-sh/ty/issues/1732 Fixes https://github.com/astral-sh/ty/issues/1800 ## Summary At each fixpoint iteration, we union the "previous" and "current" iteration types, to ensure that the type can only widen at each iteration. This prevents oscillation and ensures convergence. But some unions triggered by this behavior (in particular, unions of differently-specialized generic-aliases of the same class) never simplify, and cause spurious errors. Since we haven't seen examples of oscillating types involving class-literal or generic-alias types, just don't union those. There may be more thorough/principled ways to avoid undesirable unions in fixpoint iteration, but this narrow change seems like it results in strict improvement. ## Test Plan Removes two false positive `unsupported-class-base` in mdtests, and several in the ecosystem, without causing other regression.		2025-12-11 09:53:43 -08:00
..
annotations	[ty] Avoid inferring types for invalid binary expressions in string annotations (#21911)	2025-12-11 09:40:19 +01:00
assignment	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
binary	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
boolean	Revert "[ty] Better control flow for boolean expressions that are inside if (#18010)" (#18150)	2025-05-17 08:27:32 -04:00
boundness_declaredness	[ty] Reformulation of public symbol inference test suite (#20667)	2025-10-01 14:26:17 +02:00
call	[ty] Support implicit type of `cls` in signatures (#21771)	2025-12-10 16:56:20 -05:00
class	[ty] Infer type of implicit `cls` parameter in method bodies (#21685)	2025-12-10 10:31:28 +01:00
comparison	[ty] Improve diagnostics for unsupported comparison operations (#21737)	2025-12-02 19:58:45 +00:00
comprehensions	[ty] fix global symbol lookup from eager scopes (#21317)	2025-11-12 10:15:51 -08:00
conditional	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
dataclasses	[ty] Respect `kw_only` from parent class (#21820)	2025-12-10 10:12:18 +01:00
declaration	[ty] Format conflicting types as an enumeration (#18956)	2025-06-26 14:29:33 +02:00
diagnostics	[ty] Add subdiagnostic hint if the user wrote `X = Any` rather than `X: Any` (#21777)	2025-12-03 20:42:21 +00:00
directives	[ty] Minor improvements to `assert_type` diagnostics (#21811)	2025-12-05 12:33:30 +00:00
doc	ty_python_semantic: add union type context to function call type errors	2025-05-09 13:40:51 -04:00
exception	[ty] Improve diagnostics for invalid exceptions (#21475)	2025-11-15 22:12:00 +00:00
expression	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
external	[ty] Type inference for `@asynccontextmanager` (#21876)	2025-12-09 22:49:00 +01:00
function	[ty] Improve the display of various special-form types (#21775)	2025-12-03 21:19:59 +00:00
generics	[ty] avoid unions of generic aliases of the same class in fixpoint (#21909)	2025-12-11 09:53:43 -08:00
ide_support	[ty] Support `type[T]` with type variables (#21650)	2025-11-28 09:20:24 +01:00
import	[ty] cleanup test path (#21781)	2025-12-03 21:54:50 +00:00
libraries	[ty] Generic types aliases (implicit and PEP 613) (#21553)	2025-11-28 20:38:24 +01:00
literal	[ty] Type inference for genererator expressions (#21437)	2025-11-14 13:04:11 +00:00
loops	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
narrow	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
regression	[ty] Avoid diagnostic when `typing_extensions.ParamSpec` uses `default` parameter (#21839)	2025-12-08 12:34:30 +00:00
scopes	[ty] Make `__getattr__` available for `ModuleType` instances (#21450)	2025-11-14 13:59:14 +01:00
shadowing	Rename Red Knot (#17820)	2025-05-03 19:49:15 +02:00
snapshots	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
stubs	[ty] Better invalid-assignment diagnostics (#21476)	2025-11-18 14:31:04 +01:00
subscript	[ty] support `type[tuple[...]]` (#21652)	2025-12-01 11:49:26 +01:00
suppressions	[ty] Add code action to ignore diagnostic on the current line (#21595)	2025-11-29 15:41:54 +01:00
type_compendium	[ty] Improve literal promotion heuristics (#21439)	2025-11-14 16:13:56 -05:00
type_of	[ty] Fix disjointness checks with type-of `@final` classes (#21770)	2025-12-10 15:15:10 -05:00
type_properties	[ty] Fix disjointness checks with type-of `@final` classes (#21770)	2025-12-10 15:15:10 -05:00
type_qualifiers	[ty] Avoid double-analyzing tuple in `Final` subscript (#21828)	2025-12-07 14:27:14 +00:00
unary	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
with	[ty] Type inference for `@asynccontextmanager` (#21876)	2025-12-09 22:49:00 +01:00
.mdformat.toml	Rename Red Knot (#17820)	2025-05-03 19:49:15 +02:00
async.md	[ty] Generic types aliases (implicit and PEP 613) (#21553)	2025-11-28 20:38:24 +01:00
attributes.md	[ty] Support `type[T]` with type variables (#21650)	2025-11-28 09:20:24 +01:00
bidirectional.md	[ty] Improve diagnostics for unsupported comparison operations (#21737)	2025-12-02 19:58:45 +00:00
classes.md	[ty] Fix bug where ty would think all types had an `__mro__` attribute (#20995)	2025-10-27 11:19:12 +00:00
cycle.md	[ty] remove the `visitor` parameter in the `recursive_type_normalized_impl` method (#21701)	2025-12-01 08:48:43 +01:00
decorators.md	ty_python_semantic: add union type context to function call type errors	2025-05-09 13:40:51 -04:00
del.md	[ty] No union with `Unknown` for module-global symbols (#20664)	2025-10-01 16:40:30 +02:00
deprecated.md	[ty] Consistent use of American english (in rules) (#19488)	2025-07-22 16:10:38 +02:00
descriptor_protocol.md	[ty] Use the return type of `__get__` for descriptor lookups even when `__get__` is called with incorrect arguments (#21424)	2025-11-13 12:05:10 +00:00
enums.md	[ty] Support `type[T]` with type variables (#21650)	2025-11-28 09:20:24 +01:00
exhaustiveness_checking.md	[ty] Exhaustiveness checking for generic classes (#21726)	2025-12-01 13:52:36 +01:00
final.md	[ty] Improve `@override`, `@final` and Liskov checks in cases where there are multiple reachable definitions (#21767)	2025-12-03 12:51:36 +00:00
implicit_type_aliases.md	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
instance_layout_conflict.md	[ty] initial support for `slots=True` in dataclasses (#20278)	2025-09-07 18:25:35 +01:00
intersection_types.md	[ty] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00
invalid_syntax.md	[ty] Avoid double-inference on non-tuple argument to `Annotated` (#21837)	2025-12-08 10:24:05 -05:00
known_constants.md	Rename Red Knot (#17820)	2025-05-03 19:49:15 +02:00
liskov.md	[ty] Carry generic context through when converting class into `Callable` (#21798)	2025-12-05 08:57:21 -05:00
literal_promotion.md	[ty] Narrow type context during literal promotion in generic class constructors (#21574)	2025-11-21 17:05:32 -05:00
mdtest_config.md	Rename Red Knot (#17820)	2025-05-03 19:49:15 +02:00
mdtest_custom_typeshed.md	[ty] Remove `Type::Tuple` (#19669)	2025-08-11 22:03:32 +01:00
metaclass.md	Update class literal display to use `<class 'Foo'>` style (#17889)	2025-05-06 20:11:25 -04:00
mro.md	[ty] Improve the display of various special-form types (#21775)	2025-12-03 21:19:59 +00:00
named_tuple.md	[ty] Support implicit type of `cls` in signatures (#21771)	2025-12-10 16:56:20 -05:00
overloads.md	[ty] Infer type of `self` for decorated methods and properties (#21123)	2025-10-29 21:22:38 +00:00
override.md	[ty] Improve `@override`, `@final` and Liskov checks in cases where there are multiple reachable definitions (#21767)	2025-12-03 12:51:36 +00:00
pep613_type_aliases.md	[ty] Improve the display of various special-form types (#21775)	2025-12-03 21:19:59 +00:00
pep695_type_aliases.md	[ty] Support typevar-specialized dynamic types in generic type aliases (#21730)	2025-12-03 10:00:02 +01:00
properties.md	[ty] Use the return type of `__get__` for descriptor lookups even when `__get__` is called with incorrect arguments (#21424)	2025-11-13 12:05:10 +00:00
protocols.md	Fix stack overflow with recursive generic protocols (depth limit) (#21858)	2025-12-09 09:05:18 -08:00
public_types.md	[ty] Disambiguate classes that live in different modules but have the same fully qualified names (#20756)	2025-10-08 18:27:40 +01:00
statically_known_branches.md	[ty] Rename "possibly unbound" diagnostics to "possibly missing" (#20492)	2025-09-23 14:26:55 +00:00
sys_platform.md	Rename Red Knot (#17820)	2025-05-03 19:49:15 +02:00
sys_version_info.md	[ty] support PEP 613 type aliases (#21394)	2025-11-20 17:59:35 -08:00
t_strings.md	[ty] Add support for PEP 750 t-strings (#20085)	2025-08-25 18:49:49 +00:00
terminal_statements.md	[ty] improve lazy scope place lookup (#19321)	2025-07-25 07:11:11 +00:00
ty_extensions.md	[ty] Uniformly use "not supported" in diagnostics (#21916)	2025-12-11 15:03:55 +00:00
typed_dict.md	[ty] add `SyntheticTypedDictType` and implement `normalized` and `is_equivalent_to` (#21784)	2025-12-10 20:36:36 +00:00
union_types.md	[ty] Introduce `TypeRelation::Redundancy` (#20602)	2025-10-03 18:35:30 +01:00
unpacking.md	[ty] Infer more precise types for collection literals (#20360)	2025-09-17 18:51:50 -04:00
unreachable.md	[ty] Add subdiagnostic hint if a variable with type `Never` is used in a type expression (#21660)	2025-11-27 12:48:18 +00:00