17bf8f6faSRichard Smith // RUN: %clang_cc1 -std=c++2a -verify %s 27bf8f6faSRichard Smith check_sizes(Lambda...L)37bf8f6faSRichard Smithtemplate<typename ...T, typename ...Lambda> void check_sizes(Lambda ...L) { 47bf8f6faSRichard Smith static_assert(((sizeof(T) == sizeof(Lambda)) && ...)); 57bf8f6faSRichard Smith } 67bf8f6faSRichard Smith f(T...v)77bf8f6faSRichard Smithtemplate<typename ...T> void f(T ...v) { 87bf8f6faSRichard Smith // Pack expansion of lambdas: each lambda captures only one pack element. 97bf8f6faSRichard Smith check_sizes<T...>([=] { (void)&v; } ...); 107bf8f6faSRichard Smith 117bf8f6faSRichard Smith // Pack expansion inside lambda: captures all pack elements. 127bf8f6faSRichard Smith auto l = [=] { ((void)&v, ...); }; 137bf8f6faSRichard Smith static_assert(sizeof(l) >= (sizeof(T) + ...)); 147bf8f6faSRichard Smith } 157bf8f6faSRichard Smith 167bf8f6faSRichard Smith template void f(int, char, double); 1730519a68SRichard Smith 1830519a68SRichard Smith namespace PR41576 { f(Xs...xs)1930519a68SRichard Smith template <class... Xs> constexpr int f(Xs ...xs) { 2030519a68SRichard Smith return [&](auto ...ys) { // expected-note {{instantiation}} 21*27a972a6SYuanfang Chen return ((xs + ys), ...); // expected-warning {{left operand of comma operator has no effect}} 2230519a68SRichard Smith }(1, 2); 2330519a68SRichard Smith } 2430519a68SRichard Smith static_assert(f(3, 4) == 6); // expected-note {{instantiation}} 2530519a68SRichard Smith } 26