Description

We have an existing code path in Type::bool that tries to prevent infinite recursion:

and a test for it here:

But this only checks the case where __bool__ has the exact type Literal[bool]. It fails if the type is a union that contains Literal[bool], for example:

def flag() -> bool: return True

class Boom:
    if flag():
        __bool__ = bool
    else:
        __bool__ = int

bool(Boom())

> cargo run --bin red_knot -- --project /path/to/folder/with/example
thread '<unknown>' has overflowed its stack
fatal runtime error: stack overflow