127 lines
4.9 KiB
C++
127 lines
4.9 KiB
C++
// RUN: %clang_cc1 -std=c++1z -verify %s
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// RUN: %clang_cc1 -std=c++2a -verify %s
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template<typename ...T> constexpr auto sum(T ...t) { return (... + t); }
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template<typename ...T> constexpr auto product(T ...t) { return (t * ...); }
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template<typename ...T> constexpr auto all(T ...t) { return (true && ... && t); }
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template<typename ...T> constexpr auto dumb(T ...t) { return (false && ... && t); }
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static_assert(sum(1, 2, 3, 4, 5) == 15);
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static_assert(product(1, 2, 3, 4, 5) == 120);
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static_assert(!all(true, true, false, true, false));
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static_assert(all(true, true, true, true, true));
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static_assert(!dumb(true, true, true, true, true));
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struct S {
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int a, b, c, d, e;
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};
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template<typename ...T> constexpr auto increment_all(T &...t) {
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(++t, ...);
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}
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constexpr bool check() {
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S s = { 1, 2, 3, 4, 5 };
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increment_all(s.a, s.b, s.c, s.d, s.e);
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return s.a == 2 && s.b == 3 && s.c == 4 && s.d == 5 && s.e == 6;
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}
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static_assert(check());
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template<int ...N> void empty() {
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static_assert((N || ...) == false);
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static_assert((N && ...) == true);
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(N, ...);
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}
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template void empty<>();
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// An empty fold-expression isn't a null pointer just because it's an integer
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// with value 0. (This is no longer an issue since empty pack expansions don't
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// produce integers any more.)
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template<int ...N> void null_ptr() {
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void *p = (N || ...); // expected-error {{rvalue of type 'bool'}}
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void *q = (N , ...); // expected-error {{rvalue of type 'void'}}
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}
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template void null_ptr<>(); // expected-note {{in instantiation of}}
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template<int ...N> void bad_empty() {
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(N + ...); // expected-error {{empty expansion for operator '+' with no fallback}}
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(N * ...); // expected-error {{empty expansion for operator '*' with no fallback}}
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(N | ...); // expected-error {{empty expansion for operator '|' with no fallback}}
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(N & ...); // expected-error {{empty expansion for operator '&' with no fallback}}
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(N - ...); // expected-error {{empty expansion for operator '-' with no fallback}}
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(N / ...); // expected-error {{empty expansion for operator '/' with no fallback}}
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(N % ...); // expected-error {{empty expansion for operator '%' with no fallback}}
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(N = ...); // expected-error {{empty expansion for operator '=' with no fallback}}
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}
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template void bad_empty<>(); // expected-note {{in instantiation of}}
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template<int ...N> void empty_with_base() {
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extern int k;
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(k = ... = N); // expected-warning{{unused}}
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void (k = ... = N); // expected-error {{expected ')'}} expected-note {{to match}}
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void ((k = ... = N));
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(void) (k = ... = N);
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}
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template void empty_with_base<>(); // expected-note {{in instantiation of}}
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template void empty_with_base<1>();
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struct A {
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struct B {
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struct C {
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struct D {
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int e;
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} d;
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} c;
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} b;
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} a;
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template<typename T, typename ...Ts> constexpr decltype(auto) apply(T &t, Ts ...ts) {
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return (t.*....*ts);
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}
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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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#if __cplusplus > 201703L
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// The <=> operator is unique among binary operators in not being a
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// fold-operator.
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// FIXME: This diagnostic is not great.
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template<typename ...T> constexpr auto spaceship1(T ...t) { return (t <=> ...); } // expected-error {{expected expression}}
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template<typename ...T> constexpr auto spaceship2(T ...t) { return (... <=> t); } // expected-error {{expected expression}}
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template<typename ...T> constexpr auto spaceship3(T ...t) { return (t <=> ... <=> 0); } // expected-error {{expected expression}}
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#endif
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// The GNU binary conditional operator ?: is not recognized as a fold-operator.
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// FIXME: Why not? This seems like it would be useful.
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template<typename ...T> constexpr auto binary_conditional1(T ...t) { return (t ?: ...); } // expected-error {{expected expression}}
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template<typename ...T> constexpr auto binary_conditional2(T ...t) { return (... ?: t); } // expected-error {{expected expression}}
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template<typename ...T> constexpr auto binary_conditional3(T ...t) { return (t ?: ... ?: 0); } // expected-error {{expected expression}}
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namespace PR41845 {
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template <int I> struct Constant {};
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template <int... Is> struct Sum {
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template <int... Js> using type = Constant<((Is + Js) + ... + 0)>; // expected-error {{pack expansion contains parameter pack 'Js' that has a different length (1 vs. 2) from outer parameter packs}}
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};
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Sum<1>::type<1, 2> x; // expected-note {{instantiation of}}
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}
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namespace PR30738 {
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namespace N {
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struct S {};
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}
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namespace T {
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void operator+(N::S, N::S) {}
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template<typename ...Ts> void f() { (Ts{} + ...); }
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}
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void g() { T::f<N::S, N::S>(); }
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template<typename T, typename ...U> auto h(U ...v) {
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T operator+(T, T); // expected-note {{candidate}}
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return (v + ...); // expected-error {{invalid operands}}
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}
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int test_h1 = h<N::S>(1, 2, 3);
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N::S test_h2 = h<N::S>(N::S(), N::S(), N::S());
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int test_h3 = h<struct X>(1, 2, 3);
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N::S test_h4 = h<struct X>(N::S(), N::S(), N::S()); // expected-note {{instantiation of}}
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}
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