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// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -fcxx-exceptions %s
// An explicitly-defaulted function may be declared constexpr only if it would
// have been implicitly declared as constexpr.
struct S1 {
constexpr S1() = default; // expected-error {{defaulted definition of default constructor is not constexpr}}
constexpr S1(const S1&) = default;
constexpr S1(S1&&) = default;
constexpr S1 &operator=(const S1&) const = default; // expected-error {{explicitly-defaulted copy assignment operator may not have}}
constexpr S1 &operator=(S1&&) const = default; // expected-error {{explicitly-defaulted move assignment operator may not have}}
constexpr ~S1() = default; // expected-error {{destructor cannot be marked constexpr}}
int n;
};
struct NoCopyMove {
constexpr NoCopyMove() {}
NoCopyMove(const NoCopyMove&);
NoCopyMove(NoCopyMove&&);
};
struct S2 {
constexpr S2() = default;
constexpr S2(const S2&) = default; // expected-error {{defaulted definition of copy constructor is not constexpr}}
constexpr S2(S2&&) = default; // expected-error {{defaulted definition of move constructor is not constexpr}}
NoCopyMove ncm;
};
// If a function is explicitly defaulted on its first declaration
// -- it is implicitly considered to be constexpr if the implicit declaration
// would be
struct S3 {
S3() = default;
S3(const S3&) = default;
S3(S3&&) = default;
constexpr S3(int n) : n(n) {}
int n;
};
constexpr S3 s3a = S3(0);
constexpr S3 s3b = s3a;
constexpr S3 s3c = S3();
constexpr S3 s3d; // expected-error {{default initialization of an object of const type 'const S3' requires a user-provided default constructor}}
struct S4 {
S4() = default;
S4(const S4&) = default; // expected-note {{here}}
S4(S4&&) = default; // expected-note {{here}}
NoCopyMove ncm;
};
constexpr S4 s4a{}; // ok
constexpr S4 s4b = S4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor}}
constexpr S4 s4c = s4a; // expected-error {{constant expression}} expected-note {{non-constexpr constructor}}
struct S5 {
constexpr S5();
int n = 1, m = n + 3;
};
constexpr S5::S5() = default;
static_assert(S5().m == 4, "");
// An explicitly-defaulted function may have an exception specification only if
// it is compatible with the exception specification on an implicit declaration.
struct E1 {
E1() noexcept = default;
E1(const E1&) noexcept = default;
E1(E1&&) noexcept = default;
E1 &operator=(const E1&) noexcept = default;
E1 &operator=(E1&&) noexcept = default;
~E1() noexcept = default;
};
struct E2 {
E2() noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted default constructor does not match the calculated one}}
E2(const E2&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted copy constructor does not match the calculated one}}
E2(E2&&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted move constructor does not match the calculated one}}
E2 &operator=(const E2&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted copy assignment operator does not match the calculated one}}
E2 &operator=(E2&&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted move assignment operator does not match the calculated one}}
~E2() noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted destructor does not match the calculated one}}
};
// If a function is explicitly defaulted on its first declaration
// -- it is implicitly considered to have the same exception-specification as
// if it had been implicitly declared
struct E3 {
E3() = default;
E3(const E3&) = default;
E3(E3&&) = default;
E3 &operator=(const E3&) = default;
E3 &operator=(E3&&) = default;
~E3() = default;
};
E3 e3;
static_assert(noexcept(E3(), E3(E3()), E3(e3), e3 = E3(), e3 = e3), "");
struct E4 {
E4() noexcept(false);
E4(const E4&) noexcept(false);
E4(E4&&) noexcept(false);
E4 &operator=(const E4&) noexcept(false);
E4 &operator=(E4&&) noexcept(false);
~E4() noexcept(false);
};
struct E5 {
E5() = default;
E5(const E5&) = default;
E5(E5&&) = default;
E5 &operator=(const E5&) = default;
E5 &operator=(E5&&) = default;
~E5() = default;
E4 e4;
};
E5 e5;
static_assert(!noexcept(E5()), "");
static_assert(!noexcept(E5(static_cast<E5&&>(e5))), "");
static_assert(!noexcept(E5(e5)), "");
static_assert(!noexcept(e5 = E5()), "");
static_assert(!noexcept(e5 = e5), "");
namespace PR13492 {
struct B {
B() = default;
};
void f() {
const B b; // expected-error {{default initialization of an object of const type 'const PR13492::B' requires a user-provided default constructor}}
}
}
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