1 // P0624R2
2 // { dg-do compile { target c++11 } }
3
4 #if __cplusplus >= 201402L
5 #define A auto
6 #else
7 #define A int
8 #endif
9
10 void
f1()11 f1 ()
12 {
13 auto greater = [](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" "" { target c++17_down } }
14 decltype (greater) gt; // { dg-error "use of deleted function" "" { target c++17_down } }
15 gt = greater; // { dg-error "use of deleted function" "" { target c++17_down } }
16 }
17
18 void
f2()19 f2 ()
20 {
21 auto greater = [&](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
22 decltype (greater) gt; // { dg-error "use of deleted function" }
23 gt = greater; // { dg-error "use of deleted function" }
24 }
25
26 void
f3()27 f3 ()
28 {
29 auto greater = [=](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
30 decltype (greater) gt; // { dg-error "use of deleted function" }
31 gt = greater; // { dg-error "use of deleted function" }
32 }
33
34 void
f4(int i)35 f4 (int i)
36 {
37 auto greater = [i](A x, A y) { return x > y; }; // { dg-message "a lambda closure type has a deleted (default constructor|copy assignment operator)" }
38 decltype (greater) gt; // { dg-error "use of deleted function" }
39 gt = greater; // { dg-error "use of deleted function" }
40 }
41
42 #if __cplusplus > 201703L
43 void
f5()44 f5 ()
45 {
46 auto greater = [](auto x, auto y) constexpr { return x > y; };
47 decltype (greater) gt;
48 static_assert (!gt (1, 2));
49 static_assert (gt (4, 3));
50 static_assert (!gt (3.5, 3.75));
51 static_assert (gt (3.5, 3.25));
52 gt = greater;
53 static_assert (!gt (1, 2));
54 static_assert (gt (4, 3));
55 static_assert (!gt (3.5, 3.75));
56 static_assert (gt (3.5, 3.25));
57 }
58 #endif
59