--- /dev/null
+warning: the feature `return_position_impl_trait_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+ --> $DIR/default-method-constraint.rs:7:12
+ |
+LL | #![feature(return_position_impl_trait_in_trait)]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+ = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+ = note: `#[warn(incomplete_features)]` on by default
+
+warning: 1 warning emitted
+