mirror of https://github.com/astral-sh/ruff synced 2026-01-21 13:30:49 -05:00

Files

Alex Waygood 5a18e93d65 [ty] Make special cases for subscript inference exhaustive (#22035 )

## Summary

Fixes https://github.com/astral-sh/ty/issues/2015. We weren't recursing
into the value of a type alias when we should have been.

There are situations where we should also be recursing into the
bounds/constraints of a typevar. I initially tried to do that as well in
this PR, but that seems... trickier. For now I'm cutting scope; this PR
does, however, add several failing tests for those cases.

## Test Plan

added mdtests

2026-01-15 00:18:54 +00:00

1.3 KiB

Raw Blame History

Subscripts involving type aliases

Aliases are expanded during analysis of subscripts.

[environment]
python-version = "3.12"

from typing_extensions import TypeAlias, Literal

ImplicitTuple = tuple[str, int, int]
PEP613Tuple: TypeAlias = tuple[str, int, int]
type PEP695Tuple = tuple[str, int, int]

ImplicitZero = Literal[0]
PEP613Zero: TypeAlias = Literal[0]
type PEP695Zero = Literal[0]

def f(
    implicit_tuple: ImplicitTuple,
    pep_613_tuple: PEP613Tuple,
    pep_695_tuple: PEP695Tuple,
    implicit_zero: ImplicitZero,
    pep_613_zero: PEP613Zero,
    pep_695_zero: PEP695Zero,
):
    reveal_type(implicit_tuple[:2])  # revealed: tuple[str, int]
    reveal_type(implicit_tuple[implicit_zero])  # revealed: str
    reveal_type(implicit_tuple[pep_613_zero])  # revealed: str
    reveal_type(implicit_tuple[pep_695_zero])  # revealed: str

    reveal_type(pep_613_tuple[:2])  # revealed: tuple[str, int]
    reveal_type(pep_613_tuple[implicit_zero])  # revealed: str
    reveal_type(pep_613_tuple[pep_613_zero])  # revealed: str
    reveal_type(pep_613_tuple[pep_695_zero])  # revealed: str

    reveal_type(pep_695_tuple[:2])  # revealed: tuple[str, int]
    reveal_type(pep_695_tuple[implicit_zero])  # revealed: str
    reveal_type(pep_695_tuple[pep_613_zero])  # revealed: str
    reveal_type(pep_695_tuple[pep_695_zero])  # revealed: str

1.3 KiB Raw Blame History

Subscripts involving type aliases

1.3 KiB

Raw Blame History