[Patch] SFINAE on is_same first in variant's _Tp&& constructor

[Tim Shen via libstdc++]

On Tue, May 23, 2017 at 3:24 AM, Jonathan Wakely wrote:
> On 22/05/17 16:14 -0400, Tim Song wrote:
> Ah I see.
>
>> The original patch does that (assuming core issue 1227's resolution),
>> but the __and_ version doesn't; __and_ only short circuits the
>> immediate parameter, not things used in forming it.
>
>
> Then the original patch is OK for trunk and gcc-7-branch.
>
> Thank you Tim and Tim for the explanations.
>

Committed. I didn't bother using remove_cv<remove_reference<T>> only
because p0088r3 says decay_t.


-- 
Regards,
Tim Shen