Declarations in stubs

Unlike regular Python modules, stub files often declare module-global variables without initializing them. If these symbols are then used in the same stub, applying regular logic would lead to an undefined variable access error.

However, from the perspective of the type checker, we should treat something like symbol: type the same as symbol: type = .... In other words, assume these are bindings too.

from typing import Literal

CONSTANT: Literal[42]

# No error here, even though the variable is not initialized.
uses_constant: int = CONSTANT