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// RUN: %clang_cc1 %s -Wno-uninitialized -std=c++17 -fsyntax-only -verify
struct A {
constexpr A() : a(b + 1), b(a + 1) {} // expected-note 5{{outside its lifetime}}
int a;
int b;
};
struct B { // expected-note {{in call to 'A()'}}
A a;
};
constexpr A a1; // expected-error {{constant expression}} expected-note {{in call to 'A()'}}
constexpr A a2 = A(); // expected-error {{constant expression}} expected-note {{in call to 'A()'}}
void f() {
constexpr A a; // expected-error {{constant expression}} expected-note {{in call to 'A()'}}
}
constexpr B b1; // expected-error {{constant expression}} expected-note {{in call to 'B()'}}
constexpr B b2 = B(); // ok
static_assert(b2.a.a == 1, "");
static_assert(b2.a.b == 2, "");
struct C {
int c;
};
struct D : C { int d; };
constexpr C c1; // expected-error {{without a user-provided default constructor}}
constexpr C c2 = C(); // ok
constexpr D d1; // expected-error {{without a user-provided default constructor}}
constexpr D d2 = D(); // ok with DR1452
static_assert(D().c == 0, "");
static_assert(D().d == 0, "");
struct V : virtual C {};
template<typename T> struct Z : T {
constexpr Z() : V() {}
};
constexpr int n = Z<V>().c; // expected-error {{constant expression}} expected-note {{non-literal type 'Z<V>'}}
struct E { // expected-note {{in call to 'A()'}}
A a[2];
};
constexpr E e1; // expected-error {{constant expression}} expected-note {{in call to 'E()'}}
constexpr E e2 = E();
static_assert(e2.a[0].a == 1, "");
static_assert(e2.a[0].b == 2, "");
static_assert(e2.a[1].a == 1, "");
static_assert(e2.a[1].b == 2, "");
namespace InvalidDeclInsideConstExpr {
template <int a> struct i; // expected-note {{template is declared here}}
template <> struct i<0> {};
template <int x> constexpr auto c() {
// i<x> is valid, but it might be incomplete. g would be invalid in that case.
i<x> g; // expected-error {{implicit instantiation of undefined template 'InvalidDeclInsideConstExpr::i<1>'}}
return 0;
}
auto y = c<1>(); // expected-note {{in instantiation of function template specialization 'InvalidDeclInsideConstExpr::c<1>' requested here}}
auto x = c<0>(); // this is valid.
}
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