16       constexpr A() {}  in A()
18     constexpr A a = A();
23       constexpr B() = default;
25     constexpr B b = B();
31     constexpr C c = C();
33     constexpr void f() { C c; }  in f()
46     friend constexpr A::A() noexcept;
47     friend constexpr B::B() noexcept; // expected-error {{follows non-constexpr declaration}}
48     friend constexpr C::C() noexcept;
49     friend constexpr D::D() noexcept;
50     friend constexpr E::E() noexcept; // expected-error {{follows non-constexpr declaration}}
51     friend constexpr F::F() noexcept;
56   constexpr A a = A();
57   constexpr B b = B();
58   constexpr C c = C();
59   constexpr D d = D();
60   constexpr E e = E();
61   constexpr F f = F();
64     union A { constexpr A() = default; };
65     union B { int n; constexpr B() = default; }; // expected-error {{not constexpr}}
66     union C { int n = 0; constexpr C() = default; };
67     struct D { union {}; constexpr D() = default; };
68     struct E { union { int n; }; constexpr E() = default; }; // expected-error {{not constexpr}}
69     struct F { union { int n = 0; }; constexpr F() = default; };
71 …struct G { union { int n = 0; }; union { int m; }; constexpr G() = default; }; // expected-error {…
79       constexpr H() {} // expected-error {{must initialize all members}}  in H()
80       constexpr H(bool) : m(1) {}  in H()
81       constexpr H(char) : n(1) {} // expected-error {{must initialize all members}}  in H()
82       constexpr H(double) : m(1), n(1) {}  in H()
87   template<typename T> constexpr bool check() {  in check()
125       constexpr A() : b(2) {}  in A()
131       constexpr B() : a(1) {}  in B()
132       constexpr B(char) : b(4) {}  in B()
133       constexpr B(int) : c(3) {}  in B()
134       constexpr B(const char*) {}  in B()
149       constexpr C() : a(1) {}  in C()
150       constexpr C(char) : c(3) {}  in C()
151       constexpr C(int) : d(4) {}  in C()
152       constexpr C(float) : f(6) {}  in C()
153       constexpr C(const char*) {}  in C()
191       constexpr D() : a(0), c(0) {}  in D()
193     constexpr D d {};