error: return type captures more lifetimes than trait definition
  --> $DIR/signature-mismatch.rs:34:47
   |
LL |     fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
   |                 -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: hidden type must only reference lifetimes captured by this impl trait
  --> $DIR/signature-mismatch.rs:15:40
   |
LL |     fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
   |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a`

error: return type captures more lifetimes than trait definition
  --> $DIR/signature-mismatch.rs:39:57
   |
LL |     fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
   |                       -- this lifetime was captured     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: hidden type must only reference lifetimes captured by this impl trait
  --> $DIR/signature-mismatch.rs:16:57
   |
LL |     fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>;
   |                                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a`

error: return type captures more lifetimes than trait definition
  --> $DIR/signature-mismatch.rs:47:10
   |
LL |     fn async_fn_multiple<'a, 'b>(
   |                              -- this lifetime was captured
...
LL |     ) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> {
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: hidden type must only reference lifetimes captured by this impl trait
  --> $DIR/signature-mismatch.rs:18:12
   |
LL |         -> impl Future<Output = Vec<u8>> + Captures<'a>;
   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + Captures2<'a, 'b>`

error[E0309]: the parameter type `T` may not live long enough
  --> $DIR/signature-mismatch.rs:56:10
   |
LL |     ) -> impl Future<Output = Vec<u8>> {
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `impl Future<Output = Vec<u8>>` will meet its required lifetime bounds...
   |
note: ...that is required by this bound
  --> $DIR/signature-mismatch.rs:23:42
   |
LL |     ) -> impl Future<Output = Vec<u8>> + 'a;
   |                                          ^^
help: consider adding an explicit lifetime bound...
   |
LL |     fn async_fn_reduce_outlive<'a, 'b, T: 'a>(
   |                                         ++++

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0309`.