error[E0308]: `if` and `else` have incompatible types
  --> $DIR/dont-suggest-box-on-empty-else-arm.rs:4:12
   |
LL |       if true {
   |       ------- `if` and `else` have incompatible types
LL |           "boo2"
   |           ------ expected because of this
LL |       } else {
   |  ____________^
LL | |
LL | |     }
   | |_____^ expected `&str`, found `()`

error: aborting due to 1 previous error

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