Skip to content

Fix typing.TypeAliasType being undefined on python < 3.12 #17558

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Jul 22, 2024
Merged

Fix typing.TypeAliasType being undefined on python < 3.12 #17558

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
adb4673
Fix `typing.TypeAliasType` being undefined on python < 3.12
sobolevn Jul 22, 2024
0db0b48
Fix CI
sobolevn Jul 22, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 8 additions & 2 deletions mypy/checkexpr.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4679,7 +4679,7 @@ def visit_type_application(self, tapp: TypeApplication) -> Type:
"""
if isinstance(tapp.expr, RefExpr) and isinstance(tapp.expr.node, TypeAlias):
if tapp.expr.node.python_3_12_type_alias:
return self.named_type("typing.TypeAliasType")
return self.type_alias_type_type()
# Subscription of a (generic) alias in runtime context, expand the alias.
item = instantiate_type_alias(
tapp.expr.node,
Expand Down Expand Up @@ -4743,7 +4743,7 @@ class LongName(Generic[T]): ...
y = cast(A, ...)
"""
if alias.python_3_12_type_alias:
return self.named_type("typing.TypeAliasType")
return self.type_alias_type_type()
if isinstance(alias.target, Instance) and alias.target.invalid: # type: ignore[misc]
# An invalid alias, error already has been reported
return AnyType(TypeOfAny.from_error)
Expand Down Expand Up @@ -5863,6 +5863,12 @@ def named_type(self, name: str) -> Instance:
"""
return self.chk.named_type(name)

def type_alias_type_type(self) -> Instance:
"""Returns a `typing.TypeAliasType` or `typing_extensions.TypeAliasType`."""
if self.chk.options.python_version >= (3, 12):
return self.named_type("typing.TypeAliasType")
return self.named_type("typing_extensions.TypeAliasType")

def is_valid_var_arg(self, typ: Type) -> bool:
"""Is a type valid as a *args argument?"""
typ = get_proper_type(typ)
Expand Down
11 changes: 10 additions & 1 deletion test-data/unit/check-type-aliases.test
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1074,7 +1074,7 @@ x: TestType = 42
y: TestType = 'a'
z: TestType = object() # E: Incompatible types in assignment (expression has type "object", variable has type "Union[int, str]")

reveal_type(TestType) # N: Revealed type is "typing.TypeAliasType"
reveal_type(TestType) # N: Revealed type is "typing_extensions.TypeAliasType"
TestType() # E: "TypeAliasType" not callable

class A:
Expand All @@ -1084,6 +1084,15 @@ yc: A.ClassAlias = "" # E: Incompatible types in assignment (expression has typ
[builtins fixtures/tuple.pyi]
[typing fixtures/typing-full.pyi]

[case testTypeAliasTypePython311]
# flags: --python-version 3.11
# Pinning to 3.11, because 3.12 has `TypeAliasType`
from typing_extensions import TypeAliasType

TestType = TypeAliasType("TestType", int)
x: TestType = 1
[builtins fixtures/tuple.pyi]

[case testTypeAliasTypeInvalid]
from typing_extensions import TypeAliasType

Expand Down
Loading