SE-0288: Adding isPower(of:) to BinaryInteger

typesanitizer · August 28, 2020, 7:43pm

Could you specify the expected behavior when base is negative? For example, in

    // Here if base is 0, 1 or -1, return true iff self equals base.
    if base.magnitude <= 1 { return self == base }

This will return false when self == 1 and base == -1...

Also, quotientAndRemainder's documentation says:

A tuple containing the quotient and remainder of this value divided by rhs . The remainder has the same sign as rhs .

But that doesn't seem to be the case in practice.

$ echo 'print((10 as Int).quotientAndRemainder(dividingBy: -3))' | xcrun swift
(quotient: -3, remainder: 1)

That makes it unclear what the later code using quotientAndRemainder is trying to do.