error: this call to `hash` on the unit type will do nothing --> $DIR/unit_hash.rs:19:23 | LL | Foo::Empty => ().hash(&mut state), | ^^^^^^^^^^^^^^^^^^^ help: remove the call to `hash` or consider using: `0_u8.hash(&mut state)` | = note: `-D clippy::unit-hash` implied by `-D warnings` = note: the implementation of `Hash` for `()` is a no-op error: this call to `hash` on the unit type will do nothing --> $DIR/unit_hash.rs:24:5 | LL | res.hash(&mut state); | ^^^^^^^^^^^^^^^^^^^^ help: remove the call to `hash` or consider using: `0_u8.hash(&mut state)` | = note: the implementation of `Hash` for `()` is a no-op error: this call to `hash` on the unit type will do nothing --> $DIR/unit_hash.rs:27:5 | LL | do_nothing().hash(&mut state); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `hash` or consider using: `0_u8.hash(&mut state)` | = note: the implementation of `Hash` for `()` is a no-op error: aborting due to 3 previous errors