1 // RUN: %clang_cc1 -std=c++2a -verify %s
2 
3 template<typename ...T, typename ...Lambda> void check_sizes(Lambda ...L) {
4   static_assert(((sizeof(T) == sizeof(Lambda)) && ...));
5 }
6 
7 template<typename ...T> void f(T ...v) {
8   // Pack expansion of lambdas: each lambda captures only one pack element.
9   check_sizes<T...>([=] { (void)&v; } ...);
10 
11   // Pack expansion inside lambda: captures all pack elements.
12   auto l = [=] { ((void)&v, ...); };
13   static_assert(sizeof(l) >= (sizeof(T) + ...));
14 }
15 
16 template void f(int, char, double);
17 
18 namespace PR41576 {
19   template <class... Xs> constexpr int f(Xs ...xs) {
20     return [&](auto ...ys) { // expected-note {{instantiation}}
21       return ((xs + ys), ...); // expected-warning {{left operand of comma operator has no effect}}
22     }(1, 2);
23   }
24   static_assert(f(3, 4) == 6); // expected-note {{instantiation}}
25 }
26