error[E0276]: impl has stricter requirements than trait
  --> $DIR/issue-55872-1.rs:12:15
   |
LL |     fn foo<T>() -> Self::E;
   |     ----------------------- definition of `foo` from trait
...
LL |     fn foo<T: Default>() -> Self::E {
   |               ^^^^^^^ impl has extra requirement `T: Default`

error[E0277]: the trait bound `S: Copy` is not satisfied in `(S, T)`
  --> $DIR/issue-55872-1.rs:12:29
   |
LL |     fn foo<T: Default>() -> Self::E {
   |                             ^^^^^^^ within `(S, T)`, the trait `Copy` is not implemented for `S`, which is required by `(S, T): Copy`
   |
   = note: required because it appears within the type `(S, T)`
help: consider further restricting this bound
   |
LL | impl<S: Default + std::marker::Copy> Bar for S {
   |                 +++++++++++++++++++

error[E0277]: the trait bound `T: Copy` is not satisfied in `(S, T)`
  --> $DIR/issue-55872-1.rs:12:29
   |
LL |     fn foo<T: Default>() -> Self::E {
   |                             ^^^^^^^ within `(S, T)`, the trait `Copy` is not implemented for `T`, which is required by `(S, T): Copy`
   |
   = note: required because it appears within the type `(S, T)`
help: consider further restricting this bound
   |
LL |     fn foo<T: Default + std::marker::Copy>() -> Self::E {
   |                       +++++++++++++++++++

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0276, E0277.
For more information about an error, try `rustc --explain E0276`.