error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:16:25 | LL | let t: &dyn Trait = &S; | ^^ `Trait` cannot be made into an object | note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 | LL | trait Trait: Sized {} | ----- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... = note: required for `&S` to implement `CoerceUnsized<&dyn Trait>` = note: required by cast to type `&dyn Trait` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:17:17 | LL | takes_trait(&S); | ^^ `Trait` cannot be made into an object | note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 | LL | trait Trait: Sized {} | ----- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... = note: required for `&S` to implement `CoerceUnsized<&dyn Trait>` = note: required by cast to type `&dyn Trait` error[E0038]: the trait `Trait` cannot be made into an object --> $DIR/wf-convert-unsafe-trait-obj.rs:15:5 | LL | &S as &dyn Trait; | ^^ `Trait` cannot be made into an object | note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit --> $DIR/wf-convert-unsafe-trait-obj.rs:6:14 | LL | trait Trait: Sized {} | ----- ^^^^^ ...because it requires `Self: Sized` | | | this trait cannot be made into an object... = note: required for `&S` to implement `CoerceUnsized<&dyn Trait>` = note: required by cast to type `&dyn Trait` error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0038`.