1 // RUN: %clang_cc1 -std=c++17 -verify %s 2 not_constexpr()3template<typename T> int not_constexpr() { return T::error; } is_constexpr()4template<typename T> constexpr int is_constexpr() { return T::error; } // expected-error {{'::'}} 5 6 template<typename T> int not_constexpr_var = T::error; 7 template<typename T> constexpr int is_constexpr_var = T::error; // expected-error {{'::'}} 8 template<typename T> const int is_const_var = T::error; // expected-error {{'::'}} 9 template<typename T> const volatile int is_const_volatile_var = T::error; 10 template<typename T> T is_dependent_var = T::error; // expected-error {{'::'}} 11 template<typename T> int &is_reference_var = T::error; // expected-error {{'::'}} 12 template<typename T> float is_float_var = T::error; 13 test()14void test() { 15 // Do not instantiate functions referenced in unevaluated operands... 16 (void)sizeof(not_constexpr<long>()); 17 (void)sizeof(is_constexpr<long>()); 18 (void)sizeof(not_constexpr_var<long>); 19 (void)sizeof(is_constexpr_var<long>); 20 (void)sizeof(is_const_var<long>); 21 (void)sizeof(is_const_volatile_var<long>); 22 (void)sizeof(is_dependent_var<long>); 23 (void)sizeof(is_dependent_var<const long>); 24 (void)sizeof(is_reference_var<long>); 25 (void)sizeof(is_float_var<long>); 26 27 // ... but do if they are potentially constant evaluated, and refer to 28 // constexpr functions or to variables usable in constant expressions. 29 (void)sizeof(int{not_constexpr<int>()}); 30 (void)sizeof(int{is_constexpr<int>()}); // expected-note {{instantiation of}} 31 (void)sizeof(int{not_constexpr_var<int>}); 32 (void)sizeof(int{is_constexpr_var<int>}); // expected-note {{instantiation of}} 33 (void)sizeof(int{is_const_var<int>}); // expected-note {{instantiation of}} 34 (void)sizeof(int{is_const_volatile_var<int>}); 35 (void)sizeof(int{is_dependent_var<int>}); 36 (void)sizeof(int{is_dependent_var<const int>}); // expected-note {{instantiation of}} 37 (void)sizeof(int{is_reference_var<int>}); // expected-note {{instantiation of}} 38 (void)sizeof(int{is_float_var<int>}); // expected-error {{cannot be narrowed}} expected-note {{cast}} 39 } 40