[Bug libstdc++/79141] [6/7 Regression] std::pair p = {}; fails to compile due to ambiguous overload

[ville at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79141

--- Comment #3 from ville at gcc dot gnu.org ---
Author: ville
Date: Mon Apr  3 16:30:58 2017
New Revision: 246653

URL: https://gcc.gnu.org/viewcvs?rev=246653&root=gcc&view=rev
Log:
PR libstdc++/79141
* include/bits/stl_pair.h (__nonesuch_no_braces): New.
(operator=(typename conditional<
__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>::value,
const pair&, const __nonesuch&>::type)): Change __nonesuch
to __nonesuch_no_braces.
(operator=(typename conditional<
__not_<__and_<is_copy_assignable<_T1>,
is_copy_assignable<_T2>>>::value,
const pair&, const __nonesuch&>::type)): Likewise.
(operator=(typename conditional<
__and_<is_move_assignable<_T1>,
is_move_assignable<_T2>>::value,
pair&&, __nonesuch&&>::type)): Likewise.
* testsuite/20_util/pair/79141.cc: New.

Added:
    trunk/libstdc++-v3/testsuite/20_util/pair/79141.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/stl_pair.h