error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-generics.rs:20:5 | LL | t | ^ `Bar` cannot be made into an object | = help: consider moving `bar` to another trait 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/object-safety-generics.rs:10:8 | LL | trait Bar { | --- this trait cannot be made into an object... LL | fn bar(&self, t: T); | ^^^ ...because method `bar` has generic type parameters = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` error[E0038]: the trait `Bar` cannot be made into an object --> $DIR/object-safety-generics.rs:26:5 | LL | t as &dyn Bar | ^ `Bar` cannot be made into an object | = help: consider moving `bar` to another trait 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/object-safety-generics.rs:10:8 | LL | trait Bar { | --- this trait cannot be made into an object... LL | fn bar(&self, t: T); | ^^^ ...because method `bar` has generic type parameters = note: required because of the requirements on the impl of `CoerceUnsized<&dyn Bar>` for `&T` = note: required by cast to type `&dyn Bar` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0038`.