1const Payload = union {
 2    int: i64,
 3    float: f64,
 4    boolean: bool,
 5};
 6test "simple union" {
 7    var payload = Payload{ .int = 1234 };
 8    payload.float = 12.34;
 9}
10
11// test_error=access of union field 'float' while field 'int' is active