warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
  --> $DIR/missing-assoc-item.rs:1:12
   |
LL | #![feature(non_lifetime_binders)]
   |            ^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information
   = note: `#[warn(incomplete_features)]` on by default

error[E0223]: ambiguous associated type
  --> $DIR/missing-assoc-item.rs:6:12
   |
LL |     for<B> B::Item: Send,
   |            ^^^^^^^
   |
help: if there were a trait named `Example` with associated type `Item` implemented for `B`, you could use the fully-qualified path
   |
LL |     for<B> <B as Example>::Item: Send,
   |            ~~~~~~~~~~~~~~~~~~~~

error: aborting due to previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0223`.