error[E0767]: use of unreachable label `'a`
  --> $DIR/issue-73541.rs:4:29
   |
LL |     'a: loop {
   |     -- unreachable label defined here
LL |         || {
LL |             loop { continue 'a }
   |                             ^^ unreachable label `'a`
   |
   = note: labels are unreachable through functions, closures, async blocks and modules

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0767`.