79 lines
2.9 KiB
C++
79 lines
2.9 KiB
C++
// RUN: %clang_cc1 -std=c++1z -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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