repro.cpp

// clang++ -std=c++03 -fsyntax-only test.cpp
struct base { virtual ~base(); };

template <bool B>
struct invalid_base : base  {
   _Static_assert(B, ""); // assert must come before dtor decl
  virtual ~invalid_base();
};

template <bool B, int Dummy>
struct virtual_base : virtual invalid_base<B> {
  virtual ~virtual_base(); // must be declared
};

template <bool B>
struct test_type : virtual virtual_base<B, 1>,
                   virtual virtual_base<B, 2> {
  test_type();
};

test_type<false> b;