ruff/crates/ty_python_semantic/resources/mdtest/binary/tuples.md
Alex Waygood 7b4103bcb6
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[ty] Remove special casing for tuple addition (#19636)
2025-07-30 16:25:42 +00:00

1.9 KiB

Binary operations on tuples

Concatenation for heterogeneous tuples

reveal_type((1, 2) + (3, 4))  # revealed: tuple[Literal[1, 2, 3, 4], ...]
reveal_type(() + (1, 2))  # revealed: tuple[Literal[1, 2], ...]
reveal_type((1, 2) + ())  # revealed: tuple[Literal[1, 2], ...]
reveal_type(() + ())  # revealed: tuple[()]

def _(x: tuple[int, str], y: tuple[None, tuple[int]]):
    reveal_type(x + y)  # revealed: tuple[int | str | None | tuple[int], ...]
    reveal_type(y + x)  # revealed: tuple[None | tuple[int] | int | str, ...]

Concatenation for homogeneous tuples

def _(x: tuple[int, ...], y: tuple[str, ...]):
    reveal_type(x + x)  # revealed: tuple[int, ...]
    reveal_type(x + y)  # revealed: tuple[int | str, ...]
    reveal_type((1, 2) + x)  # revealed: tuple[int, ...]
    reveal_type(x + (3, 4))  # revealed: tuple[int, ...]
    reveal_type((1, 2) + x + (3, 4))  # revealed: tuple[int, ...]
    reveal_type((1, 2) + y + (3, 4) + x)  # revealed: tuple[int | str, ...]

We get the same results even when we use a legacy type alias, even though this involves first inferring the tuple[...] expression as a value form. (Doing so gives a generic alias of the tuple type, but as a special case, we include the full detailed tuple element specification in specializations of tuple.)

from typing import Literal

OneTwo = tuple[Literal[1], Literal[2]]
ThreeFour = tuple[Literal[3], Literal[4]]
IntTuple = tuple[int, ...]
StrTuple = tuple[str, ...]

def _(one_two: OneTwo, x: IntTuple, y: StrTuple, three_four: ThreeFour):
    reveal_type(x + x)  # revealed: tuple[int, ...]
    reveal_type(x + y)  # revealed: tuple[int | str, ...]
    reveal_type(one_two + x)  # revealed: tuple[int, ...]
    reveal_type(x + three_four)  # revealed: tuple[int, ...]
    reveal_type(one_two + x + three_four)  # revealed: tuple[int, ...]
    reveal_type(one_two + y + three_four + x)  # revealed: tuple[int | str, ...]