error[E0311]: the parameter type `U` may not live long enough
  --> $DIR/async-generics.rs:9:5
   |
LL |     async fn foo(&self) -> &(T, U);
   |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^
   |     |            |
   |     |            the parameter type `U` must be valid for the anonymous lifetime as defined here...
   |     ...so that the reference type `&(T, U)` does not outlive the data it points at
   |
help: consider adding an explicit lifetime bound
   |
LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where U: 'a;
   |                 ++++  ++           ++        +++++++++++

error[E0311]: the parameter type `T` may not live long enough
  --> $DIR/async-generics.rs:9:5
   |
LL |     async fn foo(&self) -> &(T, U);
   |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^
   |     |            |
   |     |            the parameter type `T` must be valid for the anonymous lifetime as defined here...
   |     ...so that the reference type `&(T, U)` does not outlive the data it points at
   |
help: consider adding an explicit lifetime bound
   |
LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where T: 'a;
   |                 ++++  ++           ++        +++++++++++

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0311`.