error[E0277]: the size for values of type `(dyn Trait + 'static)` cannot be known at compilation time
  --> $DIR/assoc_type_bounds_implicit_sized.rs:8:17
   |
LL |     type Item = dyn Trait;
   |                 ^^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `Sized` is not implemented for `(dyn Trait + 'static)`
note: required by a bound in `TraitWithAType::Item`
  --> $DIR/assoc_type_bounds_implicit_sized.rs:3:5
   |
LL |     type Item;
   |     ^^^^^^^^^^ required by this bound in `TraitWithAType::Item`
help: consider relaxing the implicit `Sized` restriction
   |
LL |     type Item: ?Sized;
   |              ++++++++

error: aborting due to previous error

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