1fn List(comptime Head: type, comptime Tail: type) type {
 2    return union {
 3        const Self = @This();
 4        head: Head,
 5        tail: Tail,
 6
 7        fn AppendReturnType(comptime item: anytype) type {
 8            return List(Head, List(@TypeOf(item), void));
 9        }
10    };
11}
12
13fn makeList(item: anytype) List(@TypeOf(item), void) {
14    return List(@TypeOf(item), void){ .head = item };
15}
16
17pub export fn entry() void {
18    @TypeOf(makeList(42)).AppendReturnType(64);
19}
20
21// error
22//
23// :18:43: error: value of type 'type' ignored
24// :18:43: note: all non-void values must be used
25// :18:43: note: to discard the value, assign it to '_'