[Bug c++/88417] New: partial specialization of static template variable inside class template gives wrong result

[lts-rudolph at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88417

            Bug ID: 88417
           Summary: partial specialization of static template variable
                    inside class template gives wrong result
           Product: gcc
           Version: 8.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lts-rudolph at gmx dot de
  Target Milestone: ---

If I do a partial template variable specialization inside a template class I
got the wrong results and/or if no unspecialised version is provided I got a
linker error.

 template < typename T>
class X
{
    public:
        T i;
        X(T _i): i{_i}{}

        operator T(){ return i; }
};

template < typename T2 >
class Y
{
    public:
        template <typename T>
            static X<T> x_in_y;
};

template< typename T2>
template< typename T>
X<T> Y<T2>::x_in_y{200};

template<>
template<>
X<float> Y<int>::x_in_y<float>{100};

template<>
template<>
X<int> Y<int>::x_in_y<int>{101};

// this partial specialization is never seen, but compiles without error
template<  >
template< typename T >
X<T> Y<bool>::x_in_y{77};


int main()
{
    std::cout << Y<int>::x_in_y<int> << std::endl;
    std::cout << Y<int>::x_in_y<float> << std::endl;

    std::cout << Y<float>::x_in_y<float> << std::endl;
    std::cout << Y<bool>::x_in_y<float> << std::endl;
}

expected result:
101
100
200
77