Your method's lifetime parameters do not match the trait declaration.
Erroneous code example:
```compile_fail,E0195
trait Trait {
fn bar<'a,'b:'a>(x: &'a str, y: &'b str);
}
struct Foo;
impl Trait for Foo {
fn bar<'a,'b>(x: &'a str, y: &'b str) {
// error: lifetime parameters or bounds on method `bar`
// do not match the trait declaration
}
}
```
The lifetime constraint `'b` for bar() implementation does not match the
trait declaration. Ensure lifetime declarations match exactly in both trait
declaration and implementation. Example:
```
trait Trait {
fn t<'a,'b:'a>(x: &'a str, y: &'b str);
}
struct Foo;
impl Trait for Foo {
fn t<'a,'b:'a>(x: &'a str, y: &'b str) { // ok!
}
}
```