error[E0623]: lifetime mismatch
  --> $DIR/regions-free-region-ordering-caller.rs:11:12
   |
LL | fn call2<'a, 'b>(a: &'a usize, b: &'b usize) {
   |                     ---------     ---------
   |                     |
   |                     these two types are declared with different lifetimes...
LL |     let z: Option<&'b &'a usize> = None;
   |            ^^^^^^^^^^^^^^^^^^^^^ ...but data from `a` flows into `b` here

error[E0623]: lifetime mismatch
  --> $DIR/regions-free-region-ordering-caller.rs:17:12
   |
LL | fn call3<'a, 'b>(a: &'a usize, b: &'b usize) {
   |                     ---------     ---------
   |                     |
   |                     these two types are declared with different lifetimes...
LL |     let y: Paramd<'a> = Paramd { x: a };
LL |     let z: Option<&'b Paramd<'a>> = None;
   |            ^^^^^^^^^^^^^^^^^^^^^^ ...but data from `a` flows into `b` here

error[E0623]: lifetime mismatch
  --> $DIR/regions-free-region-ordering-caller.rs:22:12
   |
LL | fn call4<'a, 'b>(a: &'a usize, b: &'b usize) {
   |                     ---------     --------- these two types are declared with different lifetimes...
LL |     let z: Option<&'a &'b usize> = None;
   |            ^^^^^^^^^^^^^^^^^^^^^ ...but data from `b` flows into `a` here

error: aborting due to 3 previous errors