error[E0426]: use of undeclared label `'b`
  --> $DIR/issue-28109.rs:6:9
   |
LL |         'b
   |         ^^ undeclared label `'b`

error[E0426]: use of undeclared label `'c`
  --> $DIR/issue-28109.rs:9:9
   |
LL |         'c
   |         ^^ undeclared label `'c`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0426`.