[Bug c++/60796] New: Default move constructor not generated by explicit template instantiaion (C++11)

["brian.freyburger at blandertechnologies dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60796

            Bug ID: 60796
           Summary: Default move constructor not generated by explicit
                    template instantiaion (C++11)
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: brian.freyburger at blandertechnologies dot com

When you use explicit template instantiation in separate compilation units, and
disable implicit instantiation, a move constructor and move assignment operator
defined as "=default" is not generated.

See example here:

A.H:

#include <memory>

template <typename T>
struct A
{
  A (T*a) : a(a) {}

  A(A&&) = default;
  A& operator =(const A&) = default;

  std::shared_ptr<T> a;
};

extern template class A<int>;

A.C:

#include "A.H"

template class A<int>;

main.C:

#include "A.H"

template class A<int>;
int main()
{
  A<int> a = new int(19);
  A<int> b = std::move(a);
}


results:

g++ -std=c++11 A.C main.C
/tmp/ccvE1IqS.o: In function `main':
main.C:(.text+0xdc): undefined reference to `A<int>::A(A<int>&&)'
collect2: error: ld returned 1 exit status