error: the function has a cyclomatic complexity of 3
  --> $DIR/cyclomatic_complexity_attr_used.rs:11:1
   |
11 | / fn kaboom() {
12 | |     if 42 == 43 {
13 | |         panic!();
14 | |     } else if "cake" == "lie" {
15 | |         println!("what?");
16 | |     }
17 | | }
   | |_^
   |
   = note: `-D cyclomatic-complexity` implied by `-D warnings`
   = help: you could split it up into multiple smaller functions