error[E0308]: mismatched types
  --> $DIR/liveness-forgot-ret.rs:3:19
   |
LL | fn f(a: isize) -> isize { if god_exists(a) { return 5; }; }
   |    -              ^^^^^ expected isize, found ()
   |    |
   |    implicitly returns `()` as its body has no tail or `return` expression
   |
   = note: expected type `isize`
              found type `()`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.