[patch] libstdc++/69240 generic operator!= for random number distributions

[Jonathan Wakely]

On 14/01/16 21:22 +0100, Daniel Krügler wrote:
>If there were an __is_direct_base_of intrinsic (or is there?), it
>seems to me that there would be no need for all these specializations
>(each one nearly taking as much space as the explicit inline
>definition of operator!) and there could be a single constrained
>operator!= that would only trigger for types that are direct base
>classes of __tag.

Yes. In fact we do have a __direct_bases intrinsic, see
<tr2/type_traits>. We'd need a bit of metaprogramming to see if
the__tag is one of __direct_bases(_Tp)... but that's doable.