protocols_subtyping error

Protocol attribute tuple element type mismatch

When a class explicitly implements a Protocol and assigns to a self.attr in __init__ where attr is declared as tupleT1, T2, ... in the protocol, each element of the assigned tuple must have a compatible type. If a parameter used in the tuple has a different type than the corresponding element type in the protocol's annotation, Basilisk reports the mismatch.

from typing import Protocol

class RGB(Protocol):
    rgb: tuple[int, int, int]

class Point(RGB):
    def __init__(self, red: int, green: int, blue: str) -> None:
        self.rgb = red, green, blue  # E — 'blue' must be 'int'

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial protocols_subtyping down per-file or per-path from your editor or pyproject.toml, or fix the code so it type-checks. See the Type System rules and the complete diagnostic reference.

Canonical URL: https://www.basilisk-python.dev/errors/protocols_subtyping