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use std::cell::Cell;
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
use std::hash::{Hash, Hasher};
use std::rc::Rc;
use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
use std::sync::Arc;
struct Key(AtomicUsize);
impl Clone for Key {
fn clone(&self) -> Self {
Key(AtomicUsize::new(self.0.load(Relaxed)))
}
}
impl PartialEq for Key {
fn eq(&self, other: &Self) -> bool {
self.0.load(Relaxed) == other.0.load(Relaxed)
}
}
impl Eq for Key {}
impl Hash for Key {
fn hash<H: Hasher>(&self, h: &mut H) {
self.0.load(Relaxed).hash(h);
}
}
fn should_not_take_this_arg(m: &mut HashMap<Key, usize>, _n: usize) -> HashSet<Key> {
let _other: HashMap<Key, bool> = HashMap::new();
m.keys().cloned().collect()
}
fn this_is_ok(_m: &mut HashMap<usize, Key>) {}
// Raw pointers are hashed by the address they point to, so it doesn't matter if they point to a
// type with interior mutability. See:
// - clippy issue: https://github.com/rust-lang/rust-clippy/issues/6745
// - std lib: https://github.com/rust-lang/rust/blob/1.54.0/library/core/src/hash/mod.rs#L717-L736
// So these are OK:
fn raw_ptr_is_ok(_m: &mut HashMap<*const Key, ()>) {}
fn raw_mut_ptr_is_ok(_m: &mut HashMap<*mut Key, ()>) {}
#[allow(unused)]
trait Trait {
type AssociatedType;
fn trait_fn(&self, set: HashSet<Self::AssociatedType>);
}
fn generics_are_ok_too<K>(_m: &mut HashSet<K>) {
// nothing to see here, move along
}
fn tuples<U>(_m: &mut HashMap<((), U), ()>) {}
fn tuples_bad<U>(_m: &mut HashMap<(Key, U), bool>) {}
fn main() {
let _ = should_not_take_this_arg(&mut HashMap::new(), 1);
this_is_ok(&mut HashMap::new());
tuples::<Key>(&mut HashMap::new());
tuples::<()>(&mut HashMap::new());
tuples_bad::<()>(&mut HashMap::new());
raw_ptr_is_ok(&mut HashMap::new());
raw_mut_ptr_is_ok(&mut HashMap::new());
let _map = HashMap::<Cell<usize>, usize>::new();
let _map = HashMap::<&mut Cell<usize>, usize>::new();
let _map = HashMap::<&mut usize, usize>::new();
// Collection types from `std` who's impl of `Hash` or `Ord` delegate their type parameters
let _map = HashMap::<Vec<Cell<usize>>, usize>::new();
let _map = HashMap::<BTreeMap<Cell<usize>, ()>, usize>::new();
let _map = HashMap::<BTreeMap<(), Cell<usize>>, usize>::new();
let _map = HashMap::<BTreeSet<Cell<usize>>, usize>::new();
let _map = HashMap::<Option<Cell<usize>>, usize>::new();
let _map = HashMap::<Option<Vec<Cell<usize>>>, usize>::new();
let _map = HashMap::<Result<&mut usize, ()>, usize>::new();
// Smart pointers from `std` who's impl of `Hash` or `Ord` delegate their type parameters
let _map = HashMap::<Box<Cell<usize>>, usize>::new();
let _map = HashMap::<Rc<Cell<usize>>, usize>::new();
let _map = HashMap::<Arc<Cell<usize>>, usize>::new();
}
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