ruff/crates/red_knot_python_semantic/resources/mdtest/annotations/deferred.md
Shunsuke Shibayama aca6254e82
[red-knot] fix eager nested scopes handling (#16916)
## Summary

From #16861, and the continuation of #16915.

This PR fixes the incorrect behavior of
`TypeInferenceBuilder::infer_name_load` in eager nested scopes.

And this PR closes #16341.

## Test Plan

New test cases are added in `annotations/deferred.md`.
2025-03-28 11:11:56 -04:00

2.9 KiB

Deferred annotations

Deferred annotations in stubs always resolve

mod.pyi:

def get_foo() -> Foo: ...
class Foo: ...
from mod import get_foo

reveal_type(get_foo())  # revealed: Foo

Deferred annotations in regular code fail

In (regular) source files, annotations are not deferred. This also tests that imports from __future__ that are not annotations are ignored.

from __future__ import with_statement as annotations

# error: [unresolved-reference]
def get_foo() -> Foo: ...

class Foo: ...

reveal_type(get_foo())  # revealed: Unknown

Deferred annotations in regular code with __future__.annotations

If __future__.annotations is imported, annotations are deferred.

from __future__ import annotations

def get_foo() -> Foo:
    return Foo()

class Foo: ...

reveal_type(get_foo())  # revealed: Foo

Deferred self-reference annotations in a class definition

from __future__ import annotations

class Foo:
    this: Foo
    # error: [unresolved-reference]
    _ = Foo()
    # error: [unresolved-reference]
    [Foo for _ in range(1)]
    a = int

    def f(self, x: Foo):
        reveal_type(x)  # revealed: Foo

    def g(self) -> Foo:
        _: Foo = self
        return self

    class Bar:
        foo: Foo
        b = int

        def f(self, x: Foo):
            return self
        # error: [unresolved-reference]
        def g(self) -> Bar:
            return self
        # error: [unresolved-reference]
        def h[T: Bar](self):
            pass

        class Baz[T: Foo]:
            pass

        # error: [unresolved-reference]
        type S = a
        type T = b

    def h[T: Bar]():
        # error: [unresolved-reference]
        return Bar()
    type Baz = Foo

Non-deferred self-reference annotations in a class definition

class Foo:
    # error: [unresolved-reference]
    this: Foo
    ok: "Foo"
    # error: [unresolved-reference]
    _ = Foo()
    # error: [unresolved-reference]
    [Foo for _ in range(1)]
    a = int

    # error: [unresolved-reference]
    def f(self, x: Foo):
        reveal_type(x)  # revealed: Unknown
    # error: [unresolved-reference]
    def g(self) -> Foo:
        _: Foo = self
        return self

    class Bar:
        # error: [unresolved-reference]
        foo: Foo
        b = int

        # error: [unresolved-reference]
        def f(self, x: Foo):
            return self
        # error: [unresolved-reference]
        def g(self) -> Bar:
            return self
        # error: [unresolved-reference]
        def h[T: Bar](self):
            pass

        class Baz[T: Foo]:
            pass

        # error: [unresolved-reference]
        type S = a
        type T = b

    def h[T: Bar]():
        # error: [unresolved-reference]
        return Bar()
    type Qux = Foo

def _():
    class C:
        # error: [unresolved-reference]
        def f(self) -> C:
            return self