[SOLVED] Does type hinting class members shadow previously defined or built-in variables?

Does type hinting class members shadow previously defined or built-in variables?

With type-hinting, defining a class in Python goes from

class SomeClass:
    def __init__(self):
        self.id = 5

to something like this

class SomeClass:
    id: int

    def __init__(self) -> None:
        self.id = 5

However, a linter like ruff has an issue with the id: int line, which apparently would shadow the built-in id. That feels like a suprising behaviour to me, since in previous, type-hint-less times, id would have always been used as self.id with no shadowing whatsoever.

So I would like to know: is there really shadowing occurring and if so, to which extent, i.e. what is the scope of this shadowing?

Solution

The builtin id will be shadowed in the scope of the class definition block. Consider the following example:

class SomeClass:
    id = lambda _: "overriden!"
    print(id(42))  # prints 'overriden'

    def __init__(self) -> None:
        print(id(42))


SomeClass()  # prints an address
print(id(42))  # prints an address