[v3 PATCH] Fix an access problem in variant.

[Jonathan Wakely]

On 08/02/17 13:56 +0000, Jonathan Wakely wrote:
>Definitely a clang bug, see
>http://melpon.org/wandbox/permlink/PkbNSpvjPrLh8rov
>
>If we remove the nested namespace we see that the friend declaration
>is declaring a second, unrelated function, and so we get an ambiguity:
>http://melpon.org/wandbox/permlink/wvmzgAzpLp5pOf86


It's https://llvm.org/bugs/show_bug.cgi?id=31852