Douglas Creager aba0bd568e [ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822) ... Generic classes are not allowed to bind or reference a typevar from an enclosing scope: ```py def f[T](x: T, y: T) -> None: class Ok[S]: ... # error: [invalid-generic-class] class Bad1[T]: ... # error: [invalid-generic-class] class Bad2(Iterable[T]): ... class C[T]: class Ok1[S]: ... # error: [invalid-generic-class] class Bad1[T]: ... # error: [invalid-generic-class] class Bad2(Iterable[T]): ... ``` It does not matter if the class uses PEP 695 or legacy syntax. It does not matter if the enclosing scope is a generic class or function. The generic class cannot even _reference_ an enclosing typevar in its base class list. This PR adds diagnostics for these cases. In addition, the PR adds better fallback behavior for generic classes that violate this rule: any enclosing typevars are not included in the class's generic context. (That ensures that we don't inadvertently try to infer specializations for those typevars in places where we shouldn't.) The `dulwich` ecosystem project has [examples of this](d912eaaffd/dulwich/config.py (L251)) that were causing new false positives on #20677. --------- Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>		2025-10-13 19:30:49 -04:00
..
annotations	[ty] Do not bind self to non-positional parameters (#20850)	2025-10-13 20:44:27 +02:00
assignment	[ty] bidirectional type inference using function return type annotations (#20528)	2025-10-11 00:38:35 +00:00
binary	Update default and latest Python versions for 3.14 (#20725)	2025-10-07 12:23:11 -04:00
boolean
boundness_declaredness	[ty] Reformulation of public symbol inference test suite (#20667)	2025-10-01 14:26:17 +02:00
call	[ty] Treat Callables as bound-method descriptors in special cases (#20802)	2025-10-13 21:17:47 +02:00
class	[ty] Fix false-positive diagnostics on super() calls (#20814)	2025-10-13 10:57:46 +00:00
comparison	[ty] detect cycles in binary comparison inference (#20446)	2025-09-17 09:45:25 +02:00
comprehensions	[ty] Async for loops and async iterables (#19634)	2025-07-30 17:40:24 +02:00
conditional	[ty] Support as-patterns in reachability analysis (#19728)	2025-08-04 20:13:50 +02:00
dataclasses	[ty] Treat functions, methods, and dynamic types as function-like Callables (#20842)	2025-10-13 15:21:55 +02:00
declaration
diagnostics	[ty] defer inference of legacy TypeVar bound/constraints/defaults (#20598)	2025-10-09 21:08:37 +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] Rename "possibly unbound" diagnostics to "possibly missing" (#20492)	2025-09-23 14:26:55 +00:00
function	[ty] Improve disambiguation of types via fully qualified names (#20141)	2025-08-29 08:44:18 +00:00
generics	[ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822)	2025-10-13 19:30:49 -04:00
ide_support	[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +00:00
import	[ty] No union with Unknown for module-global symbols (#20664)	2025-10-01 16:40:30 +02:00
literal	[ty] Treat functions, methods, and dynamic types as function-like Callables (#20842)	2025-10-13 15:21:55 +02:00
loops	[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +00:00
narrow	[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +00:00
regression
scopes	Update default and latest Python versions for 3.14 (#20725)	2025-10-07 12:23:11 -04:00
shadowing
snapshots	[ty] Diagnostic for generic classes that reference typevars in enclosing scope (#20822)	2025-10-13 19:30:49 -04:00
stubs	Update default and latest Python versions for 3.14 (#20725)	2025-10-07 12:23:11 -04:00
subscript	[ty] Rename "possibly unbound" diagnostics to "possibly missing" (#20492)	2025-09-23 14:26:55 +00:00
suppressions	[ty] Consistent use of American english (in rules) (#19488)	2025-07-22 16:10:38 +02:00
type_compendium	[ty] Type-context aware literal promotion (#20776)	2025-10-09 16:53:53 -04:00
type_of	[ty] Improve the Display for generic type[] types (#19667)	2025-07-31 19:45:01 +01:00
type_properties	[ty] Treat functions, methods, and dynamic types as function-like Callables (#20842)	2025-10-13 15:21:55 +02:00
type_qualifiers	[ty] Allow annotation expressions to be ast::Attribute nodes (#20413)	2025-09-15 12:06:48 +01:00
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] Prefer declared base class attribute over inferred attribute on subclass (#20764)	2025-10-13 09:28:57 +02:00
bidirectional.md	[ty] bidirectional type inference using function return type annotations (#20528)	2025-10-11 00:38:35 +00:00
classes.md	[ty] don't assume that deferred type inference means deferred name resolution (#20160)	2025-08-29 16:19:45 -07:00
cycle.md
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 typing.Self for the first parameter of instance methods (#20517)	2025-09-29 21:08:08 +02:00
enums.md	[ty] Enums: allow multiple aliases to point to the same member (#20669)	2025-10-01 15:51:53 +02:00
exhaustiveness_checking.md	[ty] Fix subtyping for dynamic specializations (#20592)	2025-09-26 15:05:03 +02:00
final.md
implicit_type_aliases.md	[ty] no more diverging query cycles in type expressions (#20359)	2025-09-16 16:44:11 -07:00
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] Expansion of enums into unions of literals (#19382)	2025-07-21 19:37:55 +02:00
invalid_syntax.md
known_constants.md
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] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +00:00
named_tuple.md	[ty] Use typing.Self for the first parameter of instance methods (#20517)	2025-09-29 21:08:08 +02:00
overloads.md	[ty] Improve diagnostics for bad @overload definitions (#20745)	2025-10-07 21:52:57 +00:00
pep695_type_aliases.md	[ty] defer inference of legacy TypeVar bound/constraints/defaults (#20598)	2025-10-09 21:08:37 +00:00
properties.md	[ty] "foo".startswith is not an instance of types.MethodWrapperType (#20317)	2025-09-10 11:14:26 +00:00
protocols.md	[ty] Filter out revealed-type and undefined-reveal diagnostics from mdtest snapshots (#20820)	2025-10-12 18:39:32 +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] Simplify and fix CallableTypeOf[..] implementation (#20797)	2025-10-10 12:04:37 +02:00
typed_dict.md	[ty] bidirectional type inference using function return type annotations (#20528)	2025-10-11 00:38:35 +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] Rename "possibly unbound" diagnostics to "possibly missing" (#20492)	2025-09-23 14:26:55 +00:00