[Bug c++/88368] Improper ``use of deleted function''

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88368

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
#include <type_traits>
#include <utility>

template<class T>
union trivial_helper {
    T t;
};

template <typename T>
struct trait {
  static constexpr bool value =
std::is_copy_constructible<trivial_helper<T>>::value;
};

struct BlockFrequencyInfoImplBase {

  struct BlockNode {
    int Index = 1;
    BlockNode() = default;
  };

  static constexpr bool v = trait<std::pair<BlockNode, int>>::value; // <<
remove this line to remove the error

  void print() const {
    BlockNode BB;
  }
};

Testcase included inline.  Used to be rejected e.g. in r210000, from r216750
and before r250994 used to be rejected with a different error.