| 1 | // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -fcxx-exceptions %s |
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| 2 | |
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| 3 | // An explicitly-defaulted function may be declared constexpr only if it would |
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| 4 | // have been implicitly declared as constexpr. |
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| 5 | struct S1 { |
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| 6 | constexpr S1() = default; // expected-error {{defaulted definition of default constructor is not constexpr}} |
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| 7 | constexpr S1(const S1&) = default; |
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| 8 | constexpr S1(S1&&) = default; |
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| 9 | constexpr S1 &operator=(const S1&) const = default; // expected-error {{explicitly-defaulted copy assignment operator may not have}} |
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| 10 | constexpr S1 &operator=(S1&&) const = default; // expected-error {{explicitly-defaulted move assignment operator may not have}} |
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| 11 | constexpr ~S1() = default; // expected-error {{destructor cannot be marked constexpr}} |
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| 12 | int n; |
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| 13 | }; |
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| 14 | struct NoCopyMove { |
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| 15 | constexpr NoCopyMove() {} |
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| 16 | NoCopyMove(const NoCopyMove&); |
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| 17 | NoCopyMove(NoCopyMove&&); |
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| 18 | }; |
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| 19 | struct S2 { |
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| 20 | constexpr S2() = default; |
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| 21 | constexpr S2(const S2&) = default; // expected-error {{defaulted definition of copy constructor is not constexpr}} |
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| 22 | constexpr S2(S2&&) = default; // expected-error {{defaulted definition of move constructor is not constexpr}} |
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| 23 | NoCopyMove ncm; |
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| 24 | }; |
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| 25 | |
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| 26 | // If a function is explicitly defaulted on its first declaration |
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| 27 | // -- it is implicitly considered to be constexpr if the implicit declaration |
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| 28 | // would be |
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| 29 | struct S3 { |
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| 30 | S3() = default; |
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| 31 | S3(const S3&) = default; |
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| 32 | S3(S3&&) = default; |
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| 33 | constexpr S3(int n) : n(n) {} |
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| 34 | int n; |
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| 35 | }; |
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| 36 | constexpr S3 s3a = S3(0); |
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| 37 | constexpr S3 s3b = s3a; |
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| 38 | constexpr S3 s3c = S3(); |
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| 39 | constexpr S3 s3d; // expected-error {{default initialization of an object of const type 'const S3' without a user-provided default constructor}} |
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| 40 | |
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| 41 | struct S4 { |
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| 42 | S4() = default; |
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| 43 | S4(const S4&) = default; // expected-note {{here}} |
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| 44 | S4(S4&&) = default; // expected-note {{here}} |
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| 45 | NoCopyMove ncm; |
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| 46 | }; |
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| 47 | constexpr S4 s4a{}; // ok |
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| 48 | constexpr S4 s4b = S4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor}} |
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| 49 | constexpr S4 s4c = s4a; // expected-error {{constant expression}} expected-note {{non-constexpr constructor}} |
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| 50 | |
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| 51 | struct S5 { |
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| 52 | constexpr S5(); |
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| 53 | int n = 1, m = n + 3; |
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| 54 | }; |
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| 55 | constexpr S5::S5() = default; |
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| 56 | static_assert(S5().m == 4, ""); |
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| 57 | |
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| 58 | |
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| 59 | // An explicitly-defaulted function may have an exception specification only if |
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| 60 | // it is compatible with the exception specification on an implicit declaration. |
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| 61 | struct E1 { |
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| 62 | E1() noexcept = default; |
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| 63 | E1(const E1&) noexcept = default; |
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| 64 | E1(E1&&) noexcept = default; |
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| 65 | E1 &operator=(const E1&) noexcept = default; |
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| 66 | E1 &operator=(E1&&) noexcept = default; |
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| 67 | ~E1() noexcept = default; |
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| 68 | }; |
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| 69 | struct E2 { |
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| 70 | E2() noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted default constructor does not match the calculated one}} |
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| 71 | E2(const E2&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted copy constructor does not match the calculated one}} |
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| 72 | E2(E2&&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted move constructor does not match the calculated one}} |
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| 73 | E2 &operator=(const E2&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted copy assignment operator does not match the calculated one}} |
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| 74 | E2 &operator=(E2&&) noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted move assignment operator does not match the calculated one}} |
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| 75 | ~E2() noexcept(false) = default; // expected-error {{exception specification of explicitly defaulted destructor does not match the calculated one}} |
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| 76 | }; |
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| 77 | |
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| 78 | // If a function is explicitly defaulted on its first declaration |
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| 79 | // -- it is implicitly considered to have the same exception-specification as |
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| 80 | // if it had been implicitly declared |
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| 81 | struct E3 { |
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| 82 | E3() = default; |
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| 83 | E3(const E3&) = default; |
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| 84 | E3(E3&&) = default; |
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| 85 | E3 &operator=(const E3&) = default; |
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| 86 | E3 &operator=(E3&&) = default; |
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| 87 | ~E3() = default; |
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| 88 | }; |
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| 89 | E3 e3; |
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| 90 | static_assert(noexcept(E3(), E3(E3()), E3(e3), e3 = E3(), e3 = e3), ""); |
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| 91 | struct E4 { |
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| 92 | E4() noexcept(false); |
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| 93 | E4(const E4&) noexcept(false); |
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| 94 | E4(E4&&) noexcept(false); |
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| 95 | E4 &operator=(const E4&) noexcept(false); |
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| 96 | E4 &operator=(E4&&) noexcept(false); |
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| 97 | ~E4() noexcept(false); |
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| 98 | }; |
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| 99 | struct E5 { |
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| 100 | E5() = default; |
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| 101 | E5(const E5&) = default; |
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| 102 | E5(E5&&) = default; |
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| 103 | E5 &operator=(const E5&) = default; |
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| 104 | E5 &operator=(E5&&) = default; |
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| 105 | ~E5() = default; |
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| 106 | |
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| 107 | E4 e4; |
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| 108 | }; |
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| 109 | E5 e5; |
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| 110 | static_assert(!noexcept(E5()), ""); |
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| 111 | static_assert(!noexcept(E5(static_cast<E5&&>(e5))), ""); |
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| 112 | static_assert(!noexcept(E5(e5)), ""); |
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| 113 | static_assert(!noexcept(e5 = E5()), ""); |
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| 114 | static_assert(!noexcept(e5 = e5), ""); |
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| 115 | |
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| 116 | namespace PR13492 { |
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| 117 | struct B { |
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| 118 | B() = default; |
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| 119 | int field; |
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| 120 | }; |
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| 121 | |
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| 122 | void f() { |
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| 123 | const B b; // expected-error {{default initialization of an object of const type 'const PR13492::B' without a user-provided default constructor}} |
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| 124 | } |
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| 125 | } |
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| 126 | |
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