error[E0597]: `cell` does not live long enough
  --> $DIR/refcell-in-tail-expr.rs:10:27
   |
LL |     let cell = std::cell::RefCell::new(0u8);
   |         ---- binding `cell` declared here
LL |
LL |     if let Ok(mut byte) = cell.try_borrow_mut() {
   |                           ^^^^-----------------
   |                           |
   |                           borrowed value does not live long enough
   |                           a temporary with access to the borrow is created here ...
...
LL | }
   | -
   | |
   | `cell` dropped here while still borrowed
   | ... and the borrow might be used here, when that temporary is dropped and runs the destructor for type `Result<RefMut<'_, u8>, BorrowMutError>`
   |
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
   |
LL |     };
   |      +

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0597`.