Problems with PR 21210

[Paolo Carlini]

Mark Mitchell wrote:

> That's OK with me -- if you're willing to accept the fact that this
> will silently change the meaning of:
>
>   __complex__ double c99_cd;
>   complex<double> cpp_cd(c99_cd);
>
> I just want to make sure that you're aware that what you're suggesting
> will change that; it will now simply copy the real part, and ignore
> the imaginary part.

Sorry in advance if I'm saying something stupid (I'm rather tired) but
this change would be really disruptive: consider the way we are dealing
with transcendental functions: we are *everywhere* implicitly using the
above, right?!?

Paolo.