error[E0403]: the name `'a` is already used for a generic parameter in this item's generic parameters
  --> $DIR/regions-name-duplicated.rs:1:16
   |
LL | struct Foo<'a, 'a> {
   |            --  ^^ already used
   |            |
   |            first use of `'a`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0403`.