0 is not a power of 2

[Matthias Bentrup via Digitalmars-d]

On Tuesday, 19 May 2015 at 05:16:48 UTC, Andrei Alexandrescu 
wrote:
> [...], but it wrongly returns true for x == 0.

When we're talking about modulo 2^n arithmetic, 0 is in fact a 
power of two.

Proof: 2^n mod 2^n == 0.