rust-clippy/tests/ui/unit_hash.rs

34 lines
920 B
Rust

#![warn(clippy::unit_hash)]
#![allow(clippy::let_unit_value)]
use std::collections::hash_map::DefaultHasher;
use std::hash::Hash;
enum Foo {
Empty,
WithValue(u8),
}
fn do_nothing() {}
fn main() {
let mut state = DefaultHasher::new();
let my_enum = Foo::Empty;
match my_enum {
Foo::Empty => ().hash(&mut state),
//~^ ERROR: this call to `hash` on the unit type will do nothing
//~| NOTE: the implementation of `Hash` for `()` is a no-op
Foo::WithValue(x) => x.hash(&mut state),
}
let res = ();
res.hash(&mut state);
//~^ ERROR: this call to `hash` on the unit type will do nothing
//~| NOTE: the implementation of `Hash` for `()` is a no-op
#[allow(clippy::unit_arg)]
do_nothing().hash(&mut state);
//~^ ERROR: this call to `hash` on the unit type will do nothing
//~| NOTE: the implementation of `Hash` for `()` is a no-op
}