error: `impl` item signature doesn't match `trait` item signature --> $DIR/signature-mismatch.rs:15:5 | LL | fn async_fn(&self, buff: &[u8]) -> impl Future>; | ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future> + '3` ... LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future> + 'a { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future> + '2` | = note: expected signature `fn(&'1 Struct, &'2 [u8]) -> impl Future> + '3` found signature `fn(&'1 Struct, &'2 [u8]) -> impl Future> + '2` = help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait` = help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output error: aborting due to previous error