error[E0308]: mismatched types
  --> $DIR/regions-bounds.rs:9:12
   |
LL |     return e; //~ ERROR mismatched types
   |            ^ lifetime mismatch
   |
   = note: expected type `TupleStruct<'b>`
              found type `TupleStruct<'a>`
note: the lifetime 'a as defined on the function body at 8:10...
  --> $DIR/regions-bounds.rs:8:10
   |
LL | fn a_fn1<'a,'b>(e: TupleStruct<'a>) -> TupleStruct<'b> {
   |          ^^
note: ...does not necessarily outlive the lifetime 'b as defined on the function body at 8:13
  --> $DIR/regions-bounds.rs:8:13
   |
LL | fn a_fn1<'a,'b>(e: TupleStruct<'a>) -> TupleStruct<'b> {
   |             ^^

error[E0308]: mismatched types
  --> $DIR/regions-bounds.rs:13:12
   |
LL |     return e; //~ ERROR mismatched types
   |            ^ lifetime mismatch
   |
   = note: expected type `Struct<'b>`
              found type `Struct<'a>`
note: the lifetime 'a as defined on the function body at 12:10...
  --> $DIR/regions-bounds.rs:12:10
   |
LL | fn a_fn3<'a,'b>(e: Struct<'a>) -> Struct<'b> {
   |          ^^
note: ...does not necessarily outlive the lifetime 'b as defined on the function body at 12:13
  --> $DIR/regions-bounds.rs:12:13
   |
LL | fn a_fn3<'a,'b>(e: Struct<'a>) -> Struct<'b> {
   |             ^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.