| 1 | // RUN: %clang_cc1 -std=c++1z -verify %s |
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| 2 | // RUN: %clang_cc1 -std=c++2a -verify %s |
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| 3 | |
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| 4 | template<typename ...T> constexpr auto sum(T ...t) { return (... + t); } |
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| 5 | template<typename ...T> constexpr auto product(T ...t) { return (t * ...); } |
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| 6 | template<typename ...T> constexpr auto all(T ...t) { return (true && ... && t); } |
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| 7 | template<typename ...T> constexpr auto dumb(T ...t) { return (false && ... && t); } |
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| 8 | |
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| 9 | static_assert(sum(1, 2, 3, 4, 5) == 15); |
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| 10 | static_assert(product(1, 2, 3, 4, 5) == 120); |
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| 11 | static_assert(!all(true, true, false, true, false)); |
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| 12 | static_assert(all(true, true, true, true, true)); |
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| 13 | static_assert(!dumb(true, true, true, true, true)); |
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| 14 | |
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| 15 | struct S { |
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| 16 | int a, b, c, d, e; |
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| 17 | }; |
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| 18 | template<typename ...T> constexpr auto increment_all(T &...t) { |
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| 19 | (++t, ...); |
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| 20 | } |
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| 21 | constexpr bool check() { |
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| 22 | S s = { 1, 2, 3, 4, 5 }; |
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| 23 | increment_all(s.a, s.b, s.c, s.d, s.e); |
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| 24 | return s.a == 2 && s.b == 3 && s.c == 4 && s.d == 5 && s.e == 6; |
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| 25 | } |
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| 26 | static_assert(check()); |
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| 27 | |
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| 28 | template<int ...N> void empty() { |
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| 29 | static_assert((N || ...) == false); |
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| 30 | static_assert((N && ...) == true); |
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| 31 | (N, ...); |
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| 32 | } |
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| 33 | template void empty<>(); |
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| 34 | |
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| 35 | // An empty fold-expression isn't a null pointer just because it's an integer |
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| 36 | // with value 0. (This is no longer an issue since empty pack expansions don't |
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| 37 | // produce integers any more.) |
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| 38 | template<int ...N> void null_ptr() { |
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| 39 | void *p = (N || ...); // expected-error {{rvalue of type 'bool'}} |
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| 40 | void *q = (N , ...); // expected-error {{rvalue of type 'void'}} |
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| 41 | } |
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| 42 | template void null_ptr<>(); // expected-note {{in instantiation of}} |
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| 43 | |
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| 44 | template<int ...N> void bad_empty() { |
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| 45 | (N + ...); // expected-error {{empty expansion for operator '+' with no fallback}} |
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| 46 | (N * ...); // expected-error {{empty expansion for operator '*' with no fallback}} |
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| 47 | (N | ...); // expected-error {{empty expansion for operator '|' with no fallback}} |
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| 48 | (N & ...); // expected-error {{empty expansion for operator '&' with no fallback}} |
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| 49 | (N - ...); // expected-error {{empty expansion for operator '-' with no fallback}} |
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| 50 | (N / ...); // expected-error {{empty expansion for operator '/' with no fallback}} |
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| 51 | (N % ...); // expected-error {{empty expansion for operator '%' with no fallback}} |
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| 52 | (N = ...); // expected-error {{empty expansion for operator '=' with no fallback}} |
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| 53 | } |
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| 54 | template void bad_empty<>(); // expected-note {{in instantiation of}} |
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| 55 | |
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| 56 | template<int ...N> void empty_with_base() { |
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| 57 | extern int k; |
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| 58 | (k = ... = N); // expected-warning{{unused}} |
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| 59 | |
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| 60 | void (k = ... = N); // expected-error {{expected ')'}} expected-note {{to match}} |
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| 61 | void ((k = ... = N)); |
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| 62 | (void) (k = ... = N); |
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| 63 | } |
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| 64 | template void empty_with_base<>(); // expected-note {{in instantiation of}} |
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| 65 | template void empty_with_base<1>(); |
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| 66 | |
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| 67 | struct A { |
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| 68 | struct B { |
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| 69 | struct C { |
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| 70 | struct D { |
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| 71 | int e; |
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| 72 | } d; |
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| 73 | } c; |
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| 74 | } b; |
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| 75 | } a; |
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| 76 | template<typename T, typename ...Ts> constexpr decltype(auto) apply(T &t, Ts ...ts) { |
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| 77 | return (t.*....*ts); |
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| 78 | } |
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| 79 | static_assert(&apply(a, &A::b, &A::B::c, &A::B::C::d, &A::B::C::D::e) == &a.b.c.d.e); |
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| 80 | |
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| 81 | #if __cplusplus > 201703L |
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| 82 | // The <=> operator is unique among binary operators in not being a |
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| 83 | // fold-operator. |
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| 84 | // FIXME: This diagnostic is not great. |
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| 85 | template<typename ...T> constexpr auto spaceship1(T ...t) { return (t <=> ...); } // expected-error {{expected expression}} |
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| 86 | template<typename ...T> constexpr auto spaceship2(T ...t) { return (... <=> t); } // expected-error {{expected expression}} |
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| 87 | template<typename ...T> constexpr auto spaceship3(T ...t) { return (t <=> ... <=> 0); } // expected-error {{expected expression}} |
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| 88 | #endif |
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| 89 | |
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| 90 | // The GNU binary conditional operator ?: is not recognized as a fold-operator. |
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| 91 | // FIXME: Why not? This seems like it would be useful. |
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| 92 | template<typename ...T> constexpr auto binary_conditional1(T ...t) { return (t ?: ...); } // expected-error {{expected expression}} |
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| 93 | template<typename ...T> constexpr auto binary_conditional2(T ...t) { return (... ?: t); } // expected-error {{expected expression}} |
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| 94 | template<typename ...T> constexpr auto binary_conditional3(T ...t) { return (t ?: ... ?: 0); } // expected-error {{expected expression}} |
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| 95 | |
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