error[E0277]: the trait bound `Bar<'a, T>: Foo` is not satisfied --> $DIR/hir-wf-canonicalized.rs:10:15 | LL | callback: Box>>>, | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `Bar<'a, T>` | help: this trait has no implementations, consider adding one --> $DIR/hir-wf-canonicalized.rs:3:1 | LL | trait Foo { | ^^^^^^^^^ error[E0277]: the trait bound `(dyn Callback, for<'b, 'c, 'd> Output = ()> + 'static): Foo` is not satisfied --> $DIR/hir-wf-canonicalized.rs:10:15 | LL | callback: Box>>>, | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `(dyn Callback, for<'b, 'c, 'd> Output = ()> + 'static)` | help: this trait has no implementations, consider adding one --> $DIR/hir-wf-canonicalized.rs:3:1 | LL | trait Foo { | ^^^^^^^^^ error[E0277]: the size for values of type `(dyn Callback, for<'b, 'c, 'd> Output = ()> + 'static)` cannot be known at compilation time --> $DIR/hir-wf-canonicalized.rs:10:15 | LL | callback: Box>>>, | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `(dyn Callback, for<'b, 'c, 'd> Output = ()> + 'static)` note: required by a bound in `Bar` --> $DIR/hir-wf-canonicalized.rs:9:16 | LL | struct Bar<'a, T> { | ^ required by this bound in `Bar` help: consider relaxing the implicit `Sized` restriction | LL | struct Bar<'a, T: ?Sized> { | ++++++++ error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0277`.