error[E0195]: lifetime parameters do not match the trait definition
  --> $DIR/E0195.rs:16:12
   |
LL |     fn bar<'a,'b>(x: &'a str, y: &'b str) {
   |            ^^ ^^
   |
   = note: lifetime parameters differ in whether they are early- or late-bound
note: `'a` differs between the trait and impl
  --> $DIR/E0195.rs:4:12
   |
LL | trait Trait {
   | ----------- in this trait...
...
LL |     fn bar<'a,'b:'a>(x: &'a str, y: &'b str);
   |            ^^    -- this lifetime bound makes `'a` early-bound
   |            |
   |            `'a` is early-bound
...
LL | impl Trait for Foo {
   | ------------------ in this impl...
...
LL |     fn bar<'a,'b>(x: &'a str, y: &'b str) {
   |            ^^ `'a` is late-bound
note: `'b` differs between the trait and impl
  --> $DIR/E0195.rs:4:15
   |
LL | trait Trait {
   | ----------- in this trait...
...
LL |     fn bar<'a,'b:'a>(x: &'a str, y: &'b str);
   |               ^^ -- this lifetime bound makes `'b` early-bound
   |               |
   |               `'b` is early-bound
...
LL | impl Trait for Foo {
   | ------------------ in this impl...
...
LL |     fn bar<'a,'b>(x: &'a str, y: &'b str) {
   |               ^^ `'b` is late-bound

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0195`.