[Bug c++/105742] New: accepts-invalid non-dependent call to non-static member function from unrelated class in presence of dependent base

[ppalka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105742

            Bug ID: 105742
           Summary: accepts-invalid non-dependent call to non-static
                    member function from unrelated class in presence of
                    dependent base
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ppalka at gcc dot gnu.org
  Target Milestone: ---

struct X {
  void g();
};

struct Y { };

template<class T>
struct A : T {
  void f() {
    using type = decltype(X::g());
  }
};

template struct A<Y>;


The call to the non-static X::g should be rejected at instantiation time
because X isn't a base of A<Y>, but instead we resolve the decltype at template
definition time and accept the testcase because we (incorrectly?) deem the call
to be non type dependent (and non instantiation dependent).