super() is analyzed differently from super(C, self) in generic subclass context

Bug Report

Consider a minimal reproducing example, based on one from #7362

from typing import TypeVar

T = TypeVar('T', str, int)

class C(list[T]):
    def pop_item(self, key: int) -> T:
        reveal_type(super().pop(key))
        return super().pop(key)

(https://mypy-play.net/?mypy=0.961&python=3.10&gist=ab00ab8ee474443b979cb00ea4284946)

main.py:7: note: Revealed type is "T`1"
main.py:8: error: Incompatible return value type (got "T", expected "str")
main.py:8: error: Incompatible return value type (got "T", expected "int")

This is clearly unexpected, as this should work normally. However, if instead of writing super(), we write super(C, self), which is exactly equivalent syntactically in Python 3, we get

from typing import TypeVar

T = TypeVar('T', str, int)

class C(list[T]):
    def pop_item(self, key: int) -> T:
        reveal_type(super(C, self).pop(key))
        return super(C, self).pop(key)

(https://mypy-play.net/?mypy=0.961&python=3.10&gist=44206838005bf4acfa264a42eecb0eb5)

main.py:7: note: Revealed type is "builtins.str"
main.py:7: note: Revealed type is "builtins.int"

As expected.

Possible fix

Here, Mypy is analyzing super(), differently from super(C, self), which is syntactically incorrect. If super() would instead be (correctly) parsed as super(C, self) in this case, the problem disappears. Note that this also fixes #7362 and #10130.

I don't know enough about Mypy internals to understand why Mypy does not take super() to be equal to super(C, self) here, but perhaps this could be an easy fix?

2024 edit
This reproduces on 1.8.0 as well.

Inizia eseguendo l’esempio minimo riproducibile dell’issue in mypy o nei casi mypy-play collegati, confrontando bare super() con super(C, self). Traccia come viene analizzata ciascuna forma nel contesto di una sottoclasse generica. Il lavoro è completato quando entrambe le forme rivelano lo stesso tipo concreto e l’istruzione return passa senza errori di tipo incompatibile.