1const E = enum {
 2    a,
 3    b,
 4};
 5const U = union(E) {
 6    a: u32,
 7    b: u64,
 8};
 9fn foo() E {
10    return E.b;
11}
12export fn doTheTest() u64 {
13    var u: U = foo();
14    return (&u).b;
15}
16
17// error
18//
19// :13:19: error: runtime coercion from enum 'tmp.E' to union 'tmp.U' which has non-void fields
20// :6:5: note: field 'a' has type 'u32'
21// :7:5: note: field 'b' has type 'u64'
22// :5:11: note: union declared here