error: unconstrained opaque type
  --> $DIR/issue-86800.rs:25:34
   |
LL | type TransactionFuture<'__, O> = impl '__ + Future<Output = TransactionResult<O>>;
   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: `TransactionFuture` must be used in combination with a concrete type within the same module

error: aborting due to previous error