1 // RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 2 3 // Implicitly-defined default constructors are constexpr if the implicit 4 // definition would be. 5 struct NonConstexpr1 { // expected-note {{here}} 6 int a; 7 }; 8 struct NonConstexpr2 { // expected-note {{here}} 9 NonConstexpr1 nl; 10 }; 11 struct NonConstexpr2a : NonConstexpr1 { }; 12 constexpr NonConstexpr1 nc1 = NonConstexpr1(); // ok, does not call constructor 13 constexpr NonConstexpr2 nc2 = NonConstexpr2(); // ok, does not call constructor 14 constexpr NonConstexpr2a nc2a = NonConstexpr2a(); // ok, does not call constructor 15 constexpr int nc2_a = NonConstexpr2().nl.a; // ok 16 constexpr int nc2a_a = NonConstexpr2a().a; // ok 17 struct Helper { 18 friend constexpr NonConstexpr1::NonConstexpr1(); // expected-error {{follows non-constexpr declaration}} 19 friend constexpr NonConstexpr2::NonConstexpr2(); // expected-error {{follows non-constexpr declaration}} 20 }; 21 22 struct Constexpr1 {}; 23 constexpr Constexpr1 c1 = Constexpr1(); // ok 24 struct NonConstexpr3 : virtual Constexpr1 {}; // expected-note {{struct with virtual base}} expected-note {{declared here}} 25 constexpr NonConstexpr3 nc3 = NonConstexpr3(); // expected-error {{non-literal type 'const NonConstexpr3'}} 26 27 struct Constexpr2 { 28 int a = 0; 29 }; 30 constexpr Constexpr2 c2 = Constexpr2(); // ok 31 32 int n; 33 struct Member { 34 Member() : a(n) {} 35 constexpr Member(int&a) : a(a) {} 36 int &a; 37 }; 38 struct NonConstexpr4 { // expected-note {{here}} 39 Member m; 40 }; 41 constexpr NonConstexpr4 nc4 = NonConstexpr4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor 'NonConstexpr4'}} 42 struct Constexpr3 { 43 constexpr Constexpr3() : m(n) {} 44 Member m; 45 }; 46 constexpr Constexpr3 c3 = Constexpr3(); // ok 47 struct Constexpr4 { 48 Constexpr3 m; 49 }; 50 constexpr Constexpr4 c4 = Constexpr4(); // ok 51 52 53 // This rule breaks some legal C++98 programs! 54 struct A {}; // expected-note {{here}} 55 struct B { 56 friend A::A(); // expected-error {{non-constexpr declaration of 'A' follows constexpr declaration}} 57 }; 58 59 namespace UnionCtors { 60 union A { // expected-note {{here}} 61 int a; 62 int b; 63 }; 64 union B { 65 int a; 66 int b = 5; 67 }; 68 union C { 69 int a = 5; 70 int b; 71 }; 72 struct D { 73 union { 74 int a = 5; 75 int b; 76 }; 77 union { 78 int c; 79 int d = 5; 80 }; 81 }; 82 struct E { // expected-note {{here}} 83 union { 84 int a; 85 int b; 86 }; 87 }; 88 89 struct Test { 90 friend constexpr A::A() noexcept; // expected-error {{follows non-constexpr declaration}} 91 friend constexpr B::B() noexcept; 92 friend constexpr C::C() noexcept; 93 friend constexpr D::D() noexcept; 94 friend constexpr E::E() noexcept; // expected-error {{follows non-constexpr declaration}} 95 }; 96 } 97
