error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/wf-bounds.rs:17:22
   |
LL |     fn nya() -> impl Wf<Vec<[u8]>>;
   |                      ^^^^^^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `[u8]`
note: required by a bound in `Vec`
  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL

error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/wf-bounds.rs:20:23
   |
LL |     fn nya2() -> impl Wf<[u8]>;
   |                       ^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `[u8]`
note: required by a bound in `Wf`
  --> $DIR/wf-bounds.rs:10:10
   |
LL | trait Wf<T> {
   |          ^ required by this bound in `Wf`
help: consider relaxing the implicit `Sized` restriction
   |
LL | trait Wf<T: ?Sized> {
   |           ++++++++

error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
  --> $DIR/wf-bounds.rs:23:44
   |
LL |     fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>;
   |                                            ^^^^^^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `[u8]`
note: required by a bound in `Vec`
  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL

error[E0277]: `T` doesn't implement `std::fmt::Display`
  --> $DIR/wf-bounds.rs:26:26
   |
LL |     fn nya4<T>() -> impl Wf<NeedsDisplay<T>>;
   |                          ^^^^^^^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
   |
   = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
note: required by a bound in `NeedsDisplay`
  --> $DIR/wf-bounds.rs:14:24
   |
LL | struct NeedsDisplay<T: Display>(T);
   |                        ^^^^^^^ required by this bound in `NeedsDisplay`
help: consider restricting type parameter `T`
   |
LL |     fn nya4<T: std::fmt::Display>() -> impl Wf<NeedsDisplay<T>>;
   |              +++++++++++++++++++

error: aborting due to 4 previous errors

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