ruff/crates/ty_python_semantic/resources/mdtest/subscript/instance.md

Instance subscript

Getitem unbound

class NotSubscriptable: ...

a = NotSubscriptable()[0]  # error: "Cannot subscript object of type `NotSubscriptable` with no `__getitem__` method"

Getitem not callable

class NotSubscriptable:
    __getitem__ = None

# error: "Method `__getitem__` of type `Unknown | None` is not callable on object of type `NotSubscriptable`"
a = NotSubscriptable()[0]

Valid getitem

class Identity:
    def __getitem__(self, index: int) -> int:
        return index

reveal_type(Identity()[0])  # revealed: int

Getitem union

def _(flag: bool):
    class Identity:
        if flag:
            def __getitem__(self, index: int) -> int:
                return index
        else:
            def __getitem__(self, index: int) -> str:
                return str(index)

    reveal_type(Identity()[0])  # revealed: int | str