warning: impl trait in impl method signature does not match trait method signature
  --> $DIR/foreign.rs:23:21
   |
LL |     fn bar(self) -> Arc<String> {
   |                     ^^^^^^^^^^^
   |
   = 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: the lint level is defined here
  --> $DIR/foreign.rs:22:12
   |
LL |     #[warn(refining_impl_trait)]
   |            ^^^^^^^^^^^^^^^^^^^
   = note: `#[warn(refining_impl_trait_internal)]` implied by `#[warn(refining_impl_trait)]`
help: replace the return type so that it matches the trait
   |
LL |     fn bar(self) -> impl Deref<Target = impl Sized> {
   |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

warning: impl trait in impl method signature does not match trait method signature
  --> $DIR/foreign.rs:33:21
   |
LL |     fn bar(self) -> Arc<String> {
   |                     ^^^^^^^^^^^
   |
   = 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: the lint level is defined here
  --> $DIR/foreign.rs:31:12
   |
LL |     #[warn(refining_impl_trait)]
   |            ^^^^^^^^^^^^^^^^^^^
help: replace the return type so that it matches the trait
   |
LL |     fn bar(self) -> impl Deref<Target = impl Sized> {
   |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

warning: 2 warnings emitted