138 lines · cpp
1// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -fcxx-exceptions %s2// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -fcxx-exceptions %s -fexperimental-new-constant-interpreter3 4// An explicitly-defaulted function may be declared constexpr only if it would5// have been implicitly declared as constexpr.6struct S1 {7 constexpr S1() = default; // expected-error {{defaulted definition of default constructor cannot be marked constexpr}}8 constexpr S1(const S1&) = default;9 constexpr S1(S1&&) = default;10 constexpr S1 &operator=(const S1&) const = default; // expected-error {{explicitly-defaulted copy assignment operator may not have}}11 constexpr S1 &operator=(S1&&) const = default; // expected-error {{explicitly-defaulted move assignment operator may not have}}12 constexpr ~S1() = default; // expected-error {{destructor cannot be declared constexpr}}13 int n;14};15struct NoCopyMove {16 constexpr NoCopyMove() {}17 NoCopyMove(const NoCopyMove&);18 NoCopyMove(NoCopyMove&&);19};20struct S2 {21 constexpr S2() = default;22 constexpr S2(const S2&) = default; // expected-error {{defaulted definition of copy constructor cannot be marked constexpr}}23 constexpr S2(S2&&) = default; // expected-error {{defaulted definition of move constructor cannot be marked}}24 NoCopyMove ncm;25};26 27// If a function is explicitly defaulted on its first declaration28// -- it is implicitly considered to be constexpr if the implicit declaration29// would be30struct S3 {31 S3() = default;32 S3(const S3&) = default;33 S3(S3&&) = default;34 constexpr S3(int n) : n(n) {}35 int n;36};37constexpr S3 s3a = S3(0);38constexpr S3 s3b = s3a;39constexpr S3 s3c = S3();40constexpr S3 s3d; // expected-error {{default initialization of an object of const type 'const S3' without a user-provided default constructor}}41 42struct S4 {43 S4() = default;44 S4(const S4&) = default; // expected-note {{here}}45 S4(S4&&) = default; // expected-note {{here}}46 NoCopyMove ncm;47};48constexpr S4 s4a{}; // ok49constexpr S4 s4b = S4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor}}50constexpr S4 s4c = s4a; // expected-error {{constant expression}} expected-note {{non-constexpr constructor}}51 52struct S5 {53 constexpr S5();54 int n = 1, m = n + 3;55};56constexpr S5::S5() = default;57static_assert(S5().m == 4, "");58 59 60// An explicitly-defaulted function may have a different exception specification61// from the exception specification on an implicit declaration.62struct E1 {63 E1() noexcept = default;64 E1(const E1&) noexcept = default;65 E1(E1&&) noexcept = default;66 E1 &operator=(const E1&) noexcept = default;67 E1 &operator=(E1&&) noexcept = default;68 ~E1() noexcept = default;69};70struct E2 {71 E2() noexcept(false) = default;72 E2(const E2&) noexcept(false) = default;73 E2(E2&&) noexcept(false) = default;74 E2 &operator=(const E2&) noexcept(false) = default;75 E2 &operator=(E2&&) noexcept(false) = default;76 ~E2() noexcept(false) = default;77};78E2 e2;79E2 make_e2() noexcept;80void take_e2(E2&&) noexcept;81static_assert(!noexcept(E2()), "");82static_assert(!noexcept(E2(e2)), "");83static_assert(!noexcept(E2(static_cast<E2&&>(e2))), "");84static_assert(!noexcept(e2 = e2), "");85static_assert(!noexcept(e2 = static_cast<E2&&>(e2)), "");86// FIXME: This expression results in destruction of an E2 temporary; the87// noexcept expression should evaluate to false.88static_assert(noexcept(take_e2(make_e2())), "");89 90// If a function is explicitly defaulted on its first declaration91// -- it is implicitly considered to have the same exception-specification as92// if it had been implicitly declared93struct E3 {94 E3() = default;95 E3(const E3&) = default;96 E3(E3&&) = default;97 E3 &operator=(const E3&) = default;98 E3 &operator=(E3&&) = default;99 ~E3() = default;100};101E3 e3;102static_assert(noexcept(E3(), E3(E3()), E3(e3), e3 = E3(), e3 = e3), "");103struct E4 {104 E4() noexcept(false);105 E4(const E4&) noexcept(false);106 E4(E4&&) noexcept(false);107 E4 &operator=(const E4&) noexcept(false);108 E4 &operator=(E4&&) noexcept(false);109 ~E4() noexcept(false);110};111struct E5 {112 E5() = default;113 E5(const E5&) = default;114 E5(E5&&) = default;115 E5 &operator=(const E5&) = default;116 E5 &operator=(E5&&) = default;117 ~E5() = default;118 119 E4 e4;120};121E5 e5;122static_assert(!noexcept(E5()), "");123static_assert(!noexcept(E5(static_cast<E5&&>(e5))), "");124static_assert(!noexcept(E5(e5)), "");125static_assert(!noexcept(e5 = E5()), "");126static_assert(!noexcept(e5 = e5), "");127 128namespace PR13492 {129 struct B {130 B() = default;131 int field;132 };133 134 void f() {135 const B b; // expected-error {{default initialization of an object of const type 'const B' without a user-provided default constructor}}136 }137}138