Jan 15, 2025 · Jan 12, 2025 · Jan 14, 2025 · Jan 14, 2025 · Jan 14, 2025 · Jan 14, 2025
diff --git a/mypy/semanal_typeargs.py b/mypy/semanal_typeargs.py
        if not is_error:
            # If there was already an error for the alias itself, there is no point in checking
            # the expansion, most likely it will result in the same kind of error.
 get_proper_type(t).accept(self)
 t.alias.target.accept(self)

    def visit_tuple_type(self, t: TupleType) -> None:
        t.items = flatten_nested_tuples(t.items)
diff --git a/test-data/unit/check-python312.test b/test-data/unit/check-python312.test
            class G[Q]:
                def g(self, x: Q): ...
            d: G[str]

 [case testTypeAliasNormalization]
 from collections.abc import Callable
 from typing import Unpack
 from typing_extensions import TypeAlias

 type RK_function_args = tuple[float, int]
 type RK_functionBIS = Callable[[Unpack[RK_function_args], int], int]

 def ff(a: float, b: int, c: int) -> int:
    return 2

 bis: RK_functionBIS = ff
 res: int = bis(1.0, 2, 3)
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-full.pyi]
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
 class D(C[S]): ...  # E: Invalid type argument value for "C"

 U = TypeVar("U")
 A = List[C[U]]
 x: A[bytes]  # E: Value of type variable "T" of "C" cannot be "bytes"
 A = List[C[U]]  # E: Type variable "U" not valid as type argument value for "C"
 A2 = List[C[T]]
 x: A[bytes]
 x2: A2[bytes]  # E: Value of type variable "T" of "A2" cannot be "bytes"

 V = TypeVar("V", bound=int)
 V2 = TypeVar("V2", bound=int)
 class E(Generic[V]): ...
 B = List[E[U]]
 y: B[str]  # E: Type argument "str" of "E" must be a subtype of "int"
 B = List[E[U]]  # E: Type argument "U" of "E" must be a subtype of "int"
 B2 = List[E[V2]]
 y: B[str]
 y2: B2[str]  # E: Type argument "str" of "B2" must be a subtype of "int"

 [case testValidTypeAliasValuesMoreRestrictive]
 from typing import TypeVar, Generic, List
Original file line number	Diff line number	Diff line change
Expand Up		@@ -101,7 +101,7 @@ def visit_type_alias_type(self, t: TypeAliasType) -> None:
		if not is_error:
		# If there was already an error for the alias itself, there is no point in checking
		# the expansion, most likely it will result in the same kind of error.
		get_proper_type(t).accept(self)
		t.alias.target.accept(self)

		def visit_tuple_type(self, t: TupleType) -> None:
		t.items = flatten_nested_tuples(t.items)
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1972,3 +1972,19 @@ class D:
		class G[Q]:
		def g(self, x: Q): ...
		d: G[str]

		[case testTypeAliasNormalization]
		from collections.abc import Callable
		from typing import Unpack
		from typing_extensions import TypeAlias

		type RK_function_args = tuple[float, int]
		type RK_functionBIS = Callable[[Unpack[RK_function_args], int], int]

		def ff(a: float, b: int, c: int) -> int:
		return 2

		bis: RK_functionBIS = ff
		res: int = bis(1.0, 2, 3)
		[builtins fixtures/tuple.pyi]
		[typing fixtures/typing-full.pyi]
Original file line number	Diff line number	Diff line change
Expand Up		@@ -977,13 +977,18 @@ class C(Generic[T]): ...
		class D(C[S]): ... # E: Invalid type argument value for "C"

		U = TypeVar("U")
		A = List[C[U]]
		x: A[bytes] # E: Value of type variable "T" of "C" cannot be "bytes"
		A = List[C[U]] # E: Type variable "U" not valid as type argument value for "C"
		A2 = List[C[T]]
		x: A[bytes]
		x2: A2[bytes] # E: Value of type variable "T" of "A2" cannot be "bytes"

		V = TypeVar("V", bound=int)
		V2 = TypeVar("V2", bound=int)
		class E(Generic[V]): ...
		B = List[E[U]]
		y: B[str] # E: Type argument "str" of "E" must be a subtype of "int"
		B = List[E[U]] # E: Type argument "U" of "E" must be a subtype of "int"
		B2 = List[E[V2]]
		y: B[str]
		y2: B2[str] # E: Type argument "str" of "B2" must be a subtype of "int"

		[case testValidTypeAliasValuesMoreRestrictive]
		from typing import TypeVar, Generic, List
Expand Down