mirror of
https://github.com/astral-sh/ruff.git
synced 2025-11-20 04:29:47 +00:00
238f151371
## Summary Add support for `Optional` and `Annotated` in implicit type aliases part of https://github.com/astral-sh/ty/issues/221 ## Typing conformance changes New expected diagnostics. ## Ecosystem A lot of true positives, some known limitations unrelated to this PR. ## Test Plan New Markdown tests
2.5 KiB
2.5 KiB
Annotated
Annotated attaches arbitrary metadata to a given type.
Usages
Annotated[T, ...] is equivalent to T: All metadata arguments are simply ignored.
from typing_extensions import Annotated
def _(x: Annotated[int, "foo"]):
reveal_type(x) # revealed: int
def _(x: Annotated[int, lambda: 0 + 1 * 2 // 3, _(4)]):
reveal_type(x) # revealed: int
def _(x: Annotated[int, "arbitrary", "metadata", "elements", "are", "fine"]):
reveal_type(x) # revealed: int
def _(x: Annotated[tuple[str, int], bytes]):
reveal_type(x) # revealed: tuple[str, int]
Parameterization
It is invalid to parameterize Annotated with less than two arguments.
from typing_extensions import Annotated
# error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
def _(x: Annotated):
reveal_type(x) # revealed: Unknown
def _(flag: bool):
if flag:
X = Annotated
else:
X = bool
# error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
def f(y: X):
reveal_type(y) # revealed: Unknown | bool
# error: [invalid-type-form] "`typing.Annotated` requires at least two arguments when used in a type expression"
def _(x: Annotated | bool):
reveal_type(x) # revealed: Unknown | bool
# error: [invalid-type-form] "Special form `typing.Annotated` expected at least 2 arguments (one type and at least one metadata element)"
def _(x: Annotated[()]):
reveal_type(x) # revealed: Unknown
# error: [invalid-type-form]
def _(x: Annotated[int]):
# `Annotated[T]` is invalid and will raise an error at runtime,
# but we treat it the same as `T` to provide better diagnostics later on.
# The subscription itself is still reported, regardless.
# Same for the `(int,)` form below.
reveal_type(x) # revealed: int
# error: [invalid-type-form]
def _(x: Annotated[(int,)]):
reveal_type(x) # revealed: int
Inheritance
Correctly parameterized
Inheriting from Annotated[T, ...] is equivalent to inheriting from T itself.
from typing_extensions import Annotated
from ty_extensions import reveal_mro
class C(Annotated[int, "foo"]): ...
reveal_mro(C) # revealed: (<class 'C'>, <class 'int'>, <class 'object'>)
Not parameterized
from typing_extensions import Annotated
from ty_extensions import reveal_mro
# At runtime, this is an error.
# error: [invalid-base]
class C(Annotated): ...
reveal_mro(C) # revealed: (<class 'C'>, Unknown, <class 'object'>)