error: unsatisfied lifetime constraints
  --> $DIR/regions-bounds.rs:19:12
   |
LL | fn a_fn1<'a,'b>(e: an_enum<'a>) -> an_enum<'b> {
   |          -- -- lifetime `'b` defined here
   |          |
   |          lifetime `'a` defined here
LL |     return e; //~ ERROR mismatched types
   |            ^ returning this value requires that `'a` must outlive `'b`

error: unsatisfied lifetime constraints
  --> $DIR/regions-bounds.rs:23:12
   |
LL | fn a_fn3<'a,'b>(e: a_class<'a>) -> a_class<'b> {
   |          -- -- lifetime `'b` defined here
   |          |
   |          lifetime `'a` defined here
LL |     return e; //~ ERROR mismatched types
   |            ^ returning this value requires that `'a` must outlive `'b`

error: aborting due to 2 previous errors