Nested generic self type error

[alanhdu]

mypy does not seem to like generic self types. Running mypy 0.620 with Python 3.6.6 on the following code

from typing import Generic, List, TypeVar

T = TypeVar("T")


class Nested(Generic[T]):
    def __init__(self, x: T) -> None:
        self.x = [x]

    def get(self: "Nested[List[T]]") -> T:
        return self.x[0][0]


n = Nested([1])
reveal_type(n)
reveal_type(n.x)
y = n.get()
reveal_type(y)

gives us

scratch.py:15: error: Revealed type is 'scratch.Nested[builtins.list*[builtins.int*]]'
scratch.py:16: error: Revealed type is 'builtins.list[builtins.list*[builtins.int*]]'
scratch.py:18: error: Revealed type is 'builtins.list*[builtins.int*]'

This is pretty weird -- y should be an int, not List[int], and mypy seems to do the type inference in the get method just fine.

[ilevkivskyi]

This doesn't work like this. You can't have arbitrary annotation on self (at least currently). There are similar requests, #5320, #5305. I am closing this as a duplicate of those.