1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s 2 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s 3 4 // A constexpr specifier used in an object declaration declares the object as 5 // const. 6 constexpr int a = 0; 7 extern const int a; 8 9 int i; // expected-note 2{{here}} 10 constexpr int *b = &i; 11 extern int *const b; 12 13 constexpr int &c = i; 14 extern int &c; 15 16 constexpr int (*d)(int) = 0; 17 extern int (*const d)(int); 18 19 // A variable declaration which uses the constexpr specifier shall have an 20 // initializer and shall be initialized by a constant expression. 21 constexpr int ni1; // expected-error {{default initialization of an object of const type 'const int'}} 22 constexpr struct C { C(); } ni2; // expected-error {{cannot have non-literal type 'const struct C'}} expected-note 3{{has no constexpr constructors}} 23 constexpr double &ni3; // expected-error {{declaration of reference variable 'ni3' requires an initializer}} 24 25 constexpr int nc1 = i; // expected-error {{constexpr variable 'nc1' must be initialized by a constant expression}} expected-note {{read of non-const variable 'i' is not allowed in a constant expression}} 26 constexpr C nc2 = C(); // expected-error {{cannot have non-literal type 'const C'}} 27 int &f(); // expected-note 2{{declared here}} 28 constexpr int &nc3 = f(); // expected-error {{constexpr variable 'nc3' must be initialized by a constant expression}} expected-note {{non-constexpr function 'f' cannot be used in a constant expression}} 29 constexpr int nc4(i); // expected-error {{constexpr variable 'nc4' must be initialized by a constant expression}} expected-note {{read of non-const variable 'i' is not allowed in a constant expression}} 30 constexpr C nc5((C())); // expected-error {{cannot have non-literal type 'const C'}} 31 constexpr int &nc6(f()); // expected-error {{constexpr variable 'nc6' must be initialized by a constant expression}} expected-note {{non-constexpr function 'f'}} 32 33 struct pixel { 34 int x, y; 35 }; 36 constexpr pixel ur = { 1294, 1024 }; // ok 37 constexpr pixel origin; // expected-error {{default initialization of an object of const type 'const pixel' without a user-provided default constructor}} 38 39 #if __cplusplus > 201702L 40 // A constexpr variable shall have constant destruction. 41 struct A { 42 bool ok; AA43 constexpr A(bool ok) : ok(ok) {} ~AA44 constexpr ~A() noexcept(false) { 45 void oops(); // expected-note 2{{declared here}} 46 if (!ok) oops(); // expected-note 2{{non-constexpr function}} 47 } 48 }; 49 50 constexpr A const_dtor(true); 51 constexpr A non_const_dtor(false); // expected-error {{must have constant destruction}} expected-note {{in call}} 52 constexpr A arr_dtor[5] = {true, true, true, false, true}; // expected-error {{must have constant destruction}} expected-note {{in call to '&arr_dtor[3]->~A()'}} 53 #endif 54