Function extern_spec_usize_is_power_of_two 

pub fn extern_spec_usize_is_power_of_two(self_: usize) -> bool

extern spec for usize::is_power_of_two

This is not a real function: its only use is for documentation.

terminates

ghost

ensures

result == (self != $zero && self & (self - $one) == $zero)