warning: function cannot return without recursing
  --> $DIR/region-bound-on-closure-outlives-call.rs:1:1
   |
LL | fn call_rec<F>(mut f: F) -> usize where F: FnMut(usize) -> usize {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
LL |
LL |     (|x| f(x))(call_rec(f))
   |                ----------- recursive call site
   |
   = help: a `loop` may express intention better if this is on purpose
   = note: `#[warn(unconditional_recursion)]` on by default

error[E0505]: cannot move out of `f` because it is borrowed
  --> $DIR/region-bound-on-closure-outlives-call.rs:3:25
   |
LL |     (|x| f(x))(call_rec(f))
   |      --- -              ^ move out of `f` occurs here
   |      |   |
   |      |   borrow occurs due to use in closure
   |      borrow of `f` occurs here

error: aborting due to 1 previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0505`.