David Peter 9e80e5a3a6 [ty] Support type[…] and Type[…] in implicit type aliases (#21421) ... ## Summary Support `type[…]` in implicit type aliases, for example: ```py SubclassOfInt = type[int] reveal_type(SubclassOfInt) # GenericAlias def _(subclass_of_int: SubclassOfInt): reveal_type(subclass_of_int) # type[int] ``` part of https://github.com/astral-sh/ty/issues/221 ## Typing conformance ```diff -specialtypes_type.py:138:5: error[type-assertion-failure] Argument does not have asserted type `type[Any]` -specialtypes_type.py:140:5: error[type-assertion-failure] Argument does not have asserted type `type[Any]` ``` Two new tests passing ✔️ ```diff -specialtypes_type.py:146:1: error[unresolved-attribute] Object of type `GenericAlias` has no attribute `unknown` ``` An `TA4.unknown` attribute on a PEP 613 alias (`TA4: TypeAlias = type[Any]`) is being accessed, and the conformance suite expects this to be an error. Since we currently use the inferred type for these type aliases (and possibly in the future as well), we treat this as a direct access of the attribute on `type[Any]`, which falls back to an access on `Any` itself, which succeeds. 🔴 ``` +specialtypes_type.py:152:16: error[invalid-type-form] `typing.TypeVar` is not a generic class +specialtypes_type.py:156:16: error[invalid-type-form] `typing.TypeVar` is not a generic class ``` New errors because we don't handle `T = TypeVar("T"); MyType = type[T]; MyType[T]` yet. Support for this is being tracked in https://github.com/astral-sh/ty/issues/221 🔴 ## Ecosystem impact Looks mostly good, a few known problems. ## Test Plan New Markdown tests		2025-11-13 19:02:24 +01:00
..
annotations	[ty] Ensure annotation/type expressions in stub files are always deferred (#21401)	2025-11-13 17:14:54 +00:00
assignment	[ty] Handle annotated self parameter in constructor of non-invariant generic classes (#21325)	2025-11-10 19:46:49 -05:00
binary	[ty] Rename UnionType to types.UnionType (#21262)	2025-11-03 22:06:56 +01:00
boolean
boundness_declaredness	[ty] Reformulation of public symbol inference test suite (#20667)	2025-10-01 14:26:17 +02:00
call	[ty] Silence false-positive diagnostics when using typing.Dict or typing.Callable as the second argument to isinstance() (#21386)	2025-11-11 19:30:01 +00:00
class	[ty] implement typing.NewType by adding Type::NewTypeInstance	2025-11-10 14:55:47 -08:00
comparison	[ty] detect cycles in binary comparison inference (#20446)	2025-09-17 09:45:25 +02:00
comprehensions	[ty] fix global symbol lookup from eager scopes (#21317)	2025-11-12 10:15:51 -08:00
conditional	[ty] Support as-patterns in reachability analysis (#19728)	2025-08-04 20:13:50 +02:00
dataclasses	[ty] Improve generic call expression inference (#21210)	2025-11-10 21:29:05 +00:00
declaration
diagnostics	[ty] continue and break statements outside loops are syntax errors (#20944)	2025-10-17 17:13:40 +00:00
directives	[ty] Use annotated parameters as type context (#20635)	2025-10-03 17:14:51 -04:00
doc
exception	[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +00:00
expression	[ty] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00
function	[ty] don't union in default type for annotated parameters (#21208)	2025-11-02 18:21:54 -05:00
generics	[ty] Ensure annotation/type expressions in stub files are always deferred (#21401)	2025-11-13 17:14:54 +00:00
ide_support	[ty] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00
import	[ty] Consider from thispackage import y to re-export y in __init__.pyi (#21387)	2025-11-11 14:41:14 -05:00
literal	[ty] Type inference for comprehensions (#20962)	2025-11-02 14:35:33 +01:00
loops	[ty] Fix bug where ty would think all types had an __mro__ attribute (#20995)	2025-10-27 11:19:12 +00:00
narrow	[ty] Ensure annotation/type expressions in stub files are always deferred (#21401)	2025-11-13 17:14:54 +00:00
regression	[ty] fix global symbol lookup from eager scopes (#21317)	2025-11-12 10:15:51 -08:00
scopes	[ty] Improve error messages for unresolved attribute diagnostics (#20963)	2025-10-19 10:58:25 +01:00
shadowing
snapshots	[ty] Further improve subscript assignment diagnostics (#21411)	2025-11-13 13:31:14 +01:00
stubs	[ty] Fix bug where ty would think all types had an __mro__ attribute (#20995)	2025-10-27 11:19:12 +00:00
subscript	[ty] Further improve subscript assignment diagnostics (#21411)	2025-11-13 13:31:14 +01:00
suppressions	[ty] Add suggestion to unknown rule diagnostics, rename unknown-rule lint to ignore-comment-unknown-rule (#20948)	2025-10-18 12:44:21 +02:00
type_compendium	[ty] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00
type_of	[ty] Support type[…] and Type[…] in implicit type aliases (#21421)	2025-11-13 19:02:24 +01:00
type_properties	[ty] introduce local variables for from imports of submodules in __init__.py(i) (#21173)	2025-11-10 23:04:56 +00:00
type_qualifiers	[ty] Fix false positive for Final attribute assignment in __init__ (#21158)	2025-11-11 12:54:05 -08:00
unary
with	[ty] Use typing.Self for the first parameter of instance methods (#20517)	2025-09-29 21:08:08 +02:00
.mdformat.toml
async.md	[ty] Support async/await, async with and yield from (#19595)	2025-07-30 11:51:21 +02:00
attributes.md	[ty] Skip eagerly evaluated scopes for attribute storing (#20856)	2025-11-11 14:45:34 -08:00
bidirectional.md	[ty] Improve generic call expression inference (#21210)	2025-11-10 21:29:05 +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] Avoid ever-growing default types (#20991)	2025-10-21 19:13:36 +02:00
decorators.md
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] Fix incorrect inference of enum.auto() for enums with non-int mixins, and imprecise inference of enum.auto() for single-member enums (#20541)	2025-11-10 17:53:08 +00:00
exhaustiveness_checking.md	[ty] Improve exhaustiveness analysis for type variables with bounds or constraints (#21172)	2025-10-31 16:51:11 -04:00
final.md
implicit_type_aliases.md	[ty] Support type[…] and Type[…] in implicit type aliases (#21421)	2025-11-13 19:02:24 +01:00
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] Implicit type aliases: Add support for typing.Union (#21363)	2025-11-12 12:59:14 +01:00
known_constants.md
literal_promotion.md	[ty] Do not promote literals in contravariant positions of generic specializations (#21171)	2025-10-31 17:48:34 +01:00
mdtest_config.md
mdtest_custom_typeshed.md	[ty] Remove Type::Tuple (#19669)	2025-08-11 22:03:32 +01:00
metaclass.md
mro.md	[ty] Rename UnionType to types.UnionType (#21262)	2025-11-03 22:06:56 +01:00
named_tuple.md	[ty] Fix bug where ty would think all types had an __mro__ attribute (#20995)	2025-10-27 11:19:12 +00:00
overloads.md	[ty] Infer type of self for decorated methods and properties (#21123)	2025-10-29 21:22:38 +00:00
paramspec.md	[ty] Ensure annotation/type expressions in stub files are always deferred (#21401)	2025-11-13 17:14:54 +00:00
pep613_type_aliases.md	[ty] Fall back to Divergent for deeply nested specializations (#20988)	2025-10-22 14:29:10 +02:00
pep695_type_aliases.md	[ty] Add cycle handling to lazy_default (#20967)	2025-10-23 10:05:08 +02:00
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	[ty] Fix bug where ty would think all types had an __mro__ attribute (#20995)	2025-10-27 11:19:12 +00:00
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
sys_version_info.md
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] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00
typed_dict.md	[ty] Further improve subscript assignment diagnostics (#21411)	2025-11-13 13:31:14 +01:00
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] Use "cannot" consistently over "can not" (#21255)	2025-11-03 10:38:20 -05:00