[Bug c++/71420] New: "‘type’ is not a class type" error for address-of operator overloaded for enum type

[nekotekina at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71420

            Bug ID: 71420
           Summary: "‘type’ is not a class type" error for address-of
                    operator overloaded for enum type
           Product: gcc
           Version: 5.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nekotekina at gmail dot com
  Target Milestone: ---

I was not using gcc compiler directly (it happened for Travis build), sorry if
the information is misleading or inaccurate.

Code example (C++11):

namespace itype
{
        enum type
        {
                unk = 0,

                add,
                sub,
                //...
        };

        // Address-of operator for decoder<>
        constexpr type operator &(type value)
        {
                return value;
        }
}

// Irrelevant, only shows the meaning of the below template
struct interpreter
{
        static void unk() { std::abort(); };

        static void add();
        static void sub();
        //...
};

template<typename D, typename T = decltype(&D::unk)>
struct decoder
{
        // Implementation omitted, low-relevant usage example:
        static constexpr auto add = &D::add;
        static constexpr auto sub = &D::sub;
};

decoder<interpreter> test1; // OK
decoder<itype::type> test2; // OK in Clang and MSVC

// Expected error: ‘itype::type’ is not a class type

int main()
{
        return 0;
}