| // PR c++/56039 |
| // { dg-do compile { target c++11 } } |
| |
| template <bool> struct BoolSink { typedef void type; }; |
| |
| template <typename T, typename U> |
| struct AddRvalueReferenceImpl { typedef T type; }; |
| |
| template <typename T> |
| struct AddRvalueReferenceImpl<T, typename BoolSink<false && |
| [] { // { dg-error "lambda" "" { target c++17_down } } |
| extern void tref(T&&); |
| }>::type> { |
| typedef T &&type; |
| }; |
| |
| template <typename T> |
| struct AddRvalueReference : AddRvalueReferenceImpl<T, void> { }; |
| |
| namespace ImplHelpers { |
| template <typename T> |
| typename AddRvalueReference<T>::type create(void); |
| } |
| |
| template <typename T, typename U, typename ...Args> |
| struct IsConstructibleImpl { enum { value = 0 }; }; |
| |
| template <typename T, typename ...Args> |
| struct IsConstructibleImpl<T, typename BoolSink<false && |
| [] { T t( ::ImplHelpers::create<Args>() ...); } // { dg-error "" } |
| >::type, Args ...> { |
| enum { value = 1 }; |
| }; |
| |
| template <typename T, typename ...Args> |
| struct IsConstructible : IsConstructibleImpl<T, void, Args ...> { }; |
| |
| struct DestroyMe { |
| ~DestroyMe() = delete; |
| }; |
| |
| static_assert(+IsConstructible<int>::value, "error"); |
| static_assert(!IsConstructible<void>::value, "error"); |
| static_assert(+IsConstructible<int [1]>::value, "error"); |
| static_assert(!IsConstructible<DestroyMe>::value, "error"); |
| static_assert(!IsConstructible<int *, char *>::value, "error"); |
| |
| static_assert(+IsConstructible<int &&, int>::value, "error"); |
| static_assert(!IsConstructible<int &&, int &>::value, "error"); |
| static_assert(+IsConstructible<int &&, int &&>::value, "error"); |
| |
| // { dg-prune-output "expected" } |
| // { dg-prune-output "does not name a class" } |
| // { dg-prune-output "static assertion" } |
| // { dg-prune-output "template argument . is invalid" } |