float.nan is not itself ?

[bearophile]

Joshua Reusch:

> why does this assertion fail:
> 
>  > assert(float.nan == float.nan);

By design, the hardware that manages floating point numbers makes a NaN not equal to everything else, including other NaNs:
http://en.wikipedia.org/wiki/NaN

In D2 "is" performs a bitwise comparison, but keep in mind there are many different NaNs (I think double.nan and double.init are different in the bits too).

Bye,
bearophile