error[E0277]: the trait bound `B: Clone` is not satisfied
  --> $DIR/issue-79224.rs:18:17
   |
LL | impl<B: ?Sized> Display for Cow<'_, B> {
   |                 ^^^^^^^ the trait `Clone` is not implemented for `B`
   |
   = note: required because of the requirements on the impl of `ToOwned` for `B`
help: consider further restricting this bound
   |
LL | impl<B: ?Sized + std::clone::Clone> Display for Cow<'_, B> {
   |                +++++++++++++++++++

error[E0277]: the trait bound `B: Clone` is not satisfied
  --> $DIR/issue-79224.rs:19:12
   |
LL |     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
   |            ^^^^^ the trait `Clone` is not implemented for `B`
   |
   = note: required because of the requirements on the impl of `ToOwned` for `B`
help: consider further restricting this bound
   |
LL | impl<B: ?Sized + std::clone::Clone> Display for Cow<'_, B> {
   |                +++++++++++++++++++

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.