error[E0046]: not all trait items implemented, missing: `partial_cmp` --> $DIR/issue-3344.rs:3:1 | LL | impl PartialOrd for Thing { | ^^^^^^^^^^^^^^^^^^^^^^^^^ missing `partial_cmp` in implementation | = help: implement the missing item: `fn partial_cmp(&self, _: &Thing) -> Option { todo!() }` error: aborting due to previous error For more information about this error, try `rustc --explain E0046`.