In this test:

struct S {
  enum [[deprecated]] E { D };
};

int main()
{
  auto a1 = S::D;
  auto a2 = S::E::D;
}

we emit a -Wdeprecated-declarations warning only for a2 but not a1, whereas clang++ warns for a1 too (twice, in fact).  I suppose we want a warning there as well.

C++20 using enum test:

enum class [[deprecated]] E { X };

int main()
{
    using enum E;
    auto a = X;
}

clang++ warns but g++ doesn't.