[v3] "SFINAE-friendly" std::common_type and more

[Paolo Carlini]

On 10/10/2012 02:06 PM, Daniel Krügler wrote:
> 2012/10/10 Paolo Carlini <paolo.carlini@oracle.com>:
>> ... tested x86_64-linux. Committed to mainline.
> I'd like to mention that this patch does not reflect what the core
> language says, e.g.
>
> static_assert(is_type<std::common_type<int&&, int&&>, int>(), "");
>
> Should assert, the correct result being int&&. The test currently
> holds because of compiler bug 53000.
If you like, please send a patchlet using the HAS_53000_FIXED 
infrastructure which you already added to mark such cases in a clear way!

Paolo.