1 // PR c++/94483
2 // { dg-do compile { target c++2a } }
3 
4 template<int... a> constexpr auto x1
5   = [...z = -a] (auto F) { return F(z...); };
6 
7 template<const int&... a> constexpr auto x2
8   = [&...z = a] (auto F) { return F(z...); };
9 
10 template<int... a> constexpr auto x3
11   = [z = -a] (auto F) { return F(z); }; // { dg-error "packs not expanded" }
12 
13 
14 constexpr auto sum = [] (auto... xs) { return (xs + ... + 0); };
15 const int y1 = 1, y2 = 2, y3 = 3;
16 
17 static_assert(x1<1,2,3>(sum) == -6);
18 static_assert(x2<y1,y2,y3>(sum) == 6);
19