generics_upper_bound error

TypeVar upper bound violation at call site

When a function parameter is annotated with a TypeVar that has an upper bound (e.g. bound=Sized), and the call site passes a literal value whose type does not satisfy that bound, Basilisk reports the violation.

from typing import Sized, TypeVar

ST = TypeVar("ST", bound=Sized)

def longer(x: ST, y: ST) -> ST:
    if len(x) > len(y):
        return x
    return y

longer(3, 3)  # E -- int does not implement Sized (__len__)

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial generics_upper_bound 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/generics_upper_bound