[Bug libstdc++/58764] [lwg/2193] error: converting to ‘const std::vector<std::basic_string<char> >’ from initializer list would use explicit constructor

["glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58764

--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Paolo Carlini from comment #2)
> As Marc clarified elsewhere before some patches of him, pre-4.9 we were
> inconsistent about this, thus I understand it could also make sense to
> resolve the inconsistency toward separate default constructor everywhere
> (slightly against the letter of C++11 as-is) or even not resolving it at
> all, leave these bits alone for now and wait for 2193 to be resolved one way
> or another. Maybe Marc has a personal opinion. How many separate default
> constructor we used to have and how many constructors the other way?

Mostly normal mode had separate constructors and debug/profile had merged
constructors.

I am in favor of applying the proposed resolution and having separate
constructors everywhere: I don't care about explicit instantiation of the whole
container class, and it has more functionality. We may want to put a
noexcept(is_nothrow_default_constructible<_Alloc>::value) on the default
constructors, not to lose anything compared to the current code.

I won't write the patch myself.