1 // PR c++/52892 2 // { dg-do compile { target c++11 } } 3 fibonacci(__SIZE_TYPE__ val)4constexpr __SIZE_TYPE__ fibonacci(__SIZE_TYPE__ val) { 5 return (val <= 2) ? 1 : fibonacci(val - 1) + fibonacci(val - 2); 6 } 7 8 template <typename Function> 9 struct Defer { DeferDefer10 constexpr Defer(const Function func_) : func(func_) { } 11 12 const Function func; 13 14 template <typename... Args> 15 constexpr auto operator () (const Args&... args) -> decltype(func(args...)) { 16 return func(args...); 17 } 18 }; 19 20 template <typename Function> make_deferred(const Function f)21constexpr Defer<Function> make_deferred(const Function f) { 22 return Defer<Function>(f); 23 } 24 main()25int main() { 26 constexpr auto deferred = make_deferred(&fibonacci); 27 static_assert(deferred(25) == 75025, "Static fibonacci call failed"); // { dg-error "no match for call" "" { target c++14 } } 28 } 29