warning: impl trait in impl method signature does not match trait method signature
  --> $DIR/expeced-refree-to-map-to-reearlybound-ice-108580.rs:10:22
   |
LL |     fn bar(&self) -> impl Iterator<Item = impl Sized> + '_;
   |                      ------------------------------------- return type from trait method defined here
...
LL |     fn bar(&self) -> impl Iterator + '_ {
   |                      ^^^^^^^^^^^^^^^^^^
   |
   = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
   = note: we are soliciting feedback, see issue #121718 <https://github.com/rust-lang/rust/issues/121718> for more information
   = note: `#[warn(refining_impl_trait_internal)]` on by default
help: replace the return type so that it matches the trait
   |
LL |     fn bar(&self) -> impl Iterator<Item = impl Sized> + '_ {
   |                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

warning: 1 warning emitted