[Bug libstdc++/60584] std::vector::emplace_back(...) use move constructor

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60584

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|c++                         |libstdc++
         Resolution|---                         |INVALID

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't know what clang does to compile it, but the code is not valid.

vector<T>::emplace_back requires that T is MoveInsertable into the vector. Foo
fails that requirement because it has a deleted copy constructor and deleted
move constructor, because NonCopyable has a user-provided copy constructor
defined as deleted.

If you want NonCopyable to be movable then you need to do this:

class NonCopyable
{
public:
    NonCopyable(){}
    NonCopyable(const NonCopyable &) = delete;
    NonCopyable(NonCopyable &&) = default;
};

With that move constructor the code works.