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// RUN: %clang_cc1 -std=c++2a -verify %s
namespace p3 {
void bar(...);
template <typename... Args> void foo(Args... args) {
(void)[... xs = args] {
bar(xs...);
};
}
void use() {
foo();
foo(1);
}
}
template<typename ...T> void f(T ...t) {
(void)[&...x = t] {
x; // expected-error {{unexpanded parameter pack 'x'}}
};
// Not OK: can't expand 'x' outside its scope.
weird((void)[&...x = t] {
return &x; // expected-error {{unexpanded parameter pack 'x'}}
}... // expected-error {{does not contain any unexpanded}}
);
// OK, capture only one 'slice' of 'x'.
weird((void)[&x = t] {
return &x;
}...
);
// 'x' is not expanded by the outer '...', but 'T' is.
weird((void)[&... x = t] {
return T() + &x; // expected-error {{unexpanded parameter pack 'x'}}
}... // expected-error {{does not contain any unexpanded}}
);
}
template<int ...a> constexpr auto x = [...z = a] (auto F) { return F(z...); };
static_assert(x<1,2,3>([](int a, int b, int c) { return 100 * a + 10 * b + c; }) == 123);
static_assert(x<1,2,3>([](int a, int b, int c) { return 100 * a + 10 * b + c; }) == 124); // expected-error {{failed}} \
// expected-note {{evaluates to '123 == 124'}}
template<int ...a> constexpr auto y = [z = a...] (auto F) { return F(z...); }; // expected-error {{must appear before the name of the capture}}
static_assert(y<1,2,3>([](int a, int b, int c) { return 100 * a + 10 * b + c; }) == 123);
static_assert(y<1,2,3>([](int a, int b, int c) { return 100 * a + 10 * b + c; }) == 124); // expected-error {{failed}} \
// expected-note {{evaluates to '123 == 124'}}
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