functional and type_traits cleanup

[Daniel Krügler]

2013/4/6 Jonathan Wakely <jwakely.gcc@gmail.com>
>

> > But the version with the default template parameter is fine and more
> > consistent with the other helpers implementation so, adopted! Here is an
> > other version of the patch for validation.
> >
> >     Daniel, I agree that inheritance with integral_constant is not as
> > obvious as before but it is still there and it is just what the compiler
> > need.
>
> I assume Daniel's reply was an HTML mail and didn't make it to the
> list, was there an objection to the change or a general comment?

Yes, I got a reply that my response was not accepted due to html
content. I hope this one gets into it. My response was more like a
general comment: My apprehension is that I after these changes not all
predicate type traits do satisfy the Library requirement anymore that
they still derive from std::integral_constant. But I have not checked
that individually.

> > I even hope that it also simplified a (very) little bit the job for
> > the compiler.
>
> I don't know if the compiler's job is easier or not, but I think with
> your change the template instantiation depth is increased by one, with
> your change we get false_type instantiated by the instantiation of
> is_convertible, rather than being done after it using its value
> member.
>
> > Ok to commit ?
>
> I'd like to hear Daniel's comment first, but if we don't hear from him
> please commit it in 24 hours. Thanks.

Thanks Jonathan. The text above more or less reflects the content of
my previous comment. I think I have no formal objection to the
changes, but after they have been applied I would like to do a more
rigorous test of the inheritance requirement.

- Daniel