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#![allow(unused)]
#![warn(
clippy::all,
clippy::style,
clippy::mem_replace_option_with_none,
clippy::mem_replace_with_default
)]
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList, VecDeque};
use std::mem;
fn replace_option_with_none() {
let mut an_option = Some(1);
let _ = mem::replace(&mut an_option, None);
let an_option = &mut Some(1);
let _ = mem::replace(an_option, None);
}
fn replace_with_default() {
let mut s = String::from("foo");
let _ = std::mem::replace(&mut s, String::default());
let s = &mut String::from("foo");
let _ = std::mem::replace(s, String::default());
let _ = std::mem::replace(s, Default::default());
let mut v = vec![123];
let _ = std::mem::replace(&mut v, Vec::default());
let _ = std::mem::replace(&mut v, Default::default());
let _ = std::mem::replace(&mut v, Vec::new());
let _ = std::mem::replace(&mut v, vec![]);
let mut hash_map: HashMap<i32, i32> = HashMap::new();
let _ = std::mem::replace(&mut hash_map, HashMap::new());
let mut btree_map: BTreeMap<i32, i32> = BTreeMap::new();
let _ = std::mem::replace(&mut btree_map, BTreeMap::new());
let mut vd: VecDeque<i32> = VecDeque::new();
let _ = std::mem::replace(&mut vd, VecDeque::new());
let mut hash_set: HashSet<&str> = HashSet::new();
let _ = std::mem::replace(&mut hash_set, HashSet::new());
let mut btree_set: BTreeSet<&str> = BTreeSet::new();
let _ = std::mem::replace(&mut btree_set, BTreeSet::new());
let mut list: LinkedList<i32> = LinkedList::new();
let _ = std::mem::replace(&mut list, LinkedList::new());
let mut binary_heap: BinaryHeap<i32> = BinaryHeap::new();
let _ = std::mem::replace(&mut binary_heap, BinaryHeap::new());
let mut tuple = (vec![1, 2], BinaryHeap::<i32>::new());
let _ = std::mem::replace(&mut tuple, (vec![], BinaryHeap::new()));
let mut refstr = "hello";
let _ = std::mem::replace(&mut refstr, "");
let mut slice: &[i32] = &[1, 2, 3];
let _ = std::mem::replace(&mut slice, &[]);
}
// lint is disabled for primitives because in this case `take`
// has no clear benefit over `replace` and sometimes is harder to read
fn dont_lint_primitive() {
let mut pbool = true;
let _ = std::mem::replace(&mut pbool, false);
let mut pint = 5;
let _ = std::mem::replace(&mut pint, 0);
}
// lint is disabled for expressions that are not used because changing to `take` is not the
// recommended fix. Additionally, the `replace` is #[must_use], so that lint will provide
// the correct suggestion
fn dont_lint_not_used() {
let mut s = String::from("foo");
std::mem::replace(&mut s, String::default());
}
fn main() {
replace_option_with_none();
replace_with_default();
dont_lint_primitive();
}
#[clippy::msrv = "1.39"]
fn msrv_1_39() {
let mut s = String::from("foo");
let _ = std::mem::replace(&mut s, String::default());
}
#[clippy::msrv = "1.40"]
fn msrv_1_40() {
let mut s = String::from("foo");
let _ = std::mem::replace(&mut s, String::default());
}
fn issue9824() {
struct Foo<'a>(Option<&'a str>);
impl<'a> std::ops::Deref for Foo<'a> {
type Target = Option<&'a str>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl<'a> std::ops::DerefMut for Foo<'a> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
struct Bar {
opt: Option<u8>,
val: String,
}
let mut f = Foo(Some("foo"));
let mut b = Bar {
opt: Some(1),
val: String::from("bar"),
};
// replace option with none
let _ = std::mem::replace(&mut f.0, None);
let _ = std::mem::replace(&mut *f, None);
let _ = std::mem::replace(&mut b.opt, None);
// replace with default
let _ = std::mem::replace(&mut b.val, String::default());
}
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