Is there a compiler bug exposed by my implementation of an is_complete type trait?

by

The problem appears to be with the definition of void_t. Defining it as 

template<typename... Ts>
struct make_void { typedef void type;};

template<typename... Ts>
using void_t = typename make_void<Ts...>::type;

instead yields the correct result (10) on both compilers (Demo).

I believe this is the same issue noted in section 2.3 of N3911, the paper proposing void_t, and CWG issue 1558. Essentially, the standard was unclear whether unused arguments in alias template specializations could result in substitution failure or are simply ignored. The resolution of the CWG issue, adopted at the Committee’s November 2014 meeting, clarifies that the shorter definition of void_t in the question should work, and GCC 5.0 implements the resolution.

More Related Contents:

  1. gcc can compile a variadic template while clang cannot
  2. constexpr and initialization of a static const void pointer with reinterpret cast, which compiler is right?
  3. Can I use C++11 with Xcode?
  4. What are the differences between -std=c++11 and -std=gnu++11?
  5. Overloaded lambdas in C++ and differences between clang and gcc
  6. Why can’t I move std::ofstream?
  7. const auto std::initializer_list difference between Clang and GCC
  8. Check if a class has a member function of a given signature
  9. Implementation C++14 make_integer_sequence
  10. Variadic template pack expansion
  11. How does #include work in C++? [duplicate]
  12. Is it a conforming compiler extension to treat non-constexpr standard library functions as constexpr?
  13. std::function vs template
  14. initializer_list and template type deduction
  15. explicit specialization of template class member function
  16. Why can’t clang with libc++ in c++0x mode link this boost::program_options example?
  17. Does MinGW-w64 support std::thread out of the box when using the Win32 threading model?
  18. Matching alias template as template argument
  19. Error enabling openmp – “ld: library not found for -lgomp” and Clang errors
  20. Is this C++11 regex error me or the compiler?
  21. How do compilers treat variable length arrays
  22. void_t “can implement concepts”?
  23. How can I output the value of an enum class in C++11
  24. How Does std::enable_if work?
  25. Returning a void?
  26. Why can I call a non-constexpr function inside a constexpr function?
  27. Why do the usual access control checking applies to names used to specify explicit instantiation when accessed through template parameters?
  28. Should std::unique_ptr be permitted
  29. Partial specialization of function templates
  30. Dynamic dispatching of template functions?

Leave a Comment