error[E0277]: the trait bound `U: Copy` is not satisfied
  --> $DIR/wf-fn-where-clause.rs:8:24
   |
LL | fn foo<T,U>() where T: ExtraCopy<U>
   |                        ^^^^^^^^^^^^ the trait `Copy` is not implemented for `U`
   |
note: required by a bound in `ExtraCopy`
  --> $DIR/wf-fn-where-clause.rs:6:19
   |
LL | trait ExtraCopy<T:Copy> { }
   |                   ^^^^ required by this bound in `ExtraCopy`
help: consider further restricting type parameter `U`
   |
LL | fn foo<T,U>() where T: ExtraCopy<U>, U: std::marker::Copy
   |                                    ++++++++++++++++++++++

error[E0038]: the trait `Copy` cannot be made into an object
  --> $DIR/wf-fn-where-clause.rs:12:16
   |
LL | fn bar() where Vec<dyn Copy>:, {}
   |                ^^^^^^^^^^^^^ `Copy` cannot be made into an object
   |
   = note: the trait cannot be made into an object because it requires `Self: Sized`
   = note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>

error[E0277]: the size for values of type `(dyn Copy + 'static)` cannot be known at compilation time
  --> $DIR/wf-fn-where-clause.rs:12:16
   |
LL | fn bar() where Vec<dyn Copy>:, {}
   |                ^^^^^^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `(dyn Copy + 'static)`
note: required by an implicit `Sized` bound in `Vec`
  --> $DIR/wf-fn-where-clause.rs:16:12
   |
LL | struct Vec<T> {
   |            ^ required by the implicit `Sized` requirement on this type parameter in `Vec`
help: you could relax the implicit `Sized` bound on `T` if it were used through indirection like `&T` or `Box<T>`
  --> $DIR/wf-fn-where-clause.rs:16:12
   |
LL | struct Vec<T> {
   |            ^ this could be changed to `T: ?Sized`...
LL |     t: T,
   |        - ...if indirection were used here: `Box<T>`

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0038, E0277.
For more information about an error, try `rustc --explain E0038`.