Error code E0195

The lifetime parameters of the method do not match the trait declaration.

Erroneous code example:

#![allow(unused)] fn main() { 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:

#![allow(unused)] fn main() { 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! } } }