error[E0623]: lifetime mismatch
  --> $DIR/ex3-both-anon-regions-one-is-struct-3.rs:14:11
   |
13 | fn foo(mut y: Ref, x: &u32) {
   |               ---     ---- these two types are declared with different lifetimes...
14 |     y.b = x; //~ ERROR lifetime mismatch
   |           ^ ...but data from `x` flows into `y` here

error: aborting due to previous error