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needless_collect: Lint LinkedList and BinaryHeap in direct usage.

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Those two types are supported already when used indirectly.
This commit adds support for direct usage as well.
This commit is contained in:
Mateusz Gacek 2021-05-05 12:17:49 -07:00
parent 59ccc1efb3
commit 171789eb45
4 changed files with 60 additions and 4 deletions
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4
clippy_lints/src/loops/needless_collect.rs
View file

@ -31,7 +31,9 @@ fn check_needless_collect_direct_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateCont
let is_empty_sugg = Some("next().is_none()".to_string());
let method_name = &*method.ident.name.as_str();
let sugg = if is_type_diagnostic_item(cx, ty, sym::vec_type) ||
is_type_diagnostic_item(cx, ty, sym::vecdeque_type) {
is_type_diagnostic_item(cx, ty, sym::vecdeque_type) ||
is_type_diagnostic_item(cx, ty, sym::LinkedList) ||
is_type_diagnostic_item(cx, ty, sym::BinaryHeap) {
match method_name {
"len" => Some("count()".to_string()),
"is_empty" => is_empty_sugg,

11
tests/ui/needless_collect.fixed
View file

@ -2,7 +2,7 @@
#![allow(unused, clippy::suspicious_map, clippy::iter_count)]
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
#[warn(clippy::needless_collect)]
#[allow(unused_variables, clippy::iter_cloned_collect, clippy::iter_next_slice)]
@ -24,4 +24,13 @@ fn main() {
sample.iter().collect::<HashSet<_>>().len();
// Neither should this
sample.iter().collect::<BTreeSet<_>>().len();
sample.iter().count();
sample.iter().next().is_none();
sample.iter().cloned().any(|x| x == 1);
sample.iter().any(|x| x == &1);
// `BinaryHeap` doesn't have `contains` method
sample.iter().count();
sample.iter().next().is_none();
}

11
tests/ui/needless_collect.rs
View file

@ -2,7 +2,7 @@
#![allow(unused, clippy::suspicious_map, clippy::iter_count)]
use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
#[warn(clippy::needless_collect)]
#[allow(unused_variables, clippy::iter_cloned_collect, clippy::iter_next_slice)]
@ -24,4 +24,13 @@ fn main() {
sample.iter().collect::<HashSet<_>>().len();
// Neither should this
sample.iter().collect::<BTreeSet<_>>().len();
sample.iter().collect::<LinkedList<_>>().len();
sample.iter().collect::<LinkedList<_>>().is_empty();
sample.iter().cloned().collect::<LinkedList<_>>().contains(&1);
sample.iter().collect::<LinkedList<_>>().contains(&&1);
// `BinaryHeap` doesn't have `contains` method
sample.iter().collect::<BinaryHeap<_>>().len();
sample.iter().collect::<BinaryHeap<_>>().is_empty();
}

38
tests/ui/needless_collect.stderr
View file

@ -30,5 +30,41 @@ error: avoid using `collect()` when not needed
LL | sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: aborting due to 5 previous errors
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:28:19
|
LL | sample.iter().collect::<LinkedList<_>>().len();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:29:19
|
LL | sample.iter().collect::<LinkedList<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:30:28
|
LL | sample.iter().cloned().collect::<LinkedList<_>>().contains(&1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == 1)`
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:31:19
|
LL | sample.iter().collect::<LinkedList<_>>().contains(&&1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == &1)`
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:34:19
|
LL | sample.iter().collect::<BinaryHeap<_>>().len();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
error: avoid using `collect()` when not needed
--> $DIR/needless_collect.rs:35:19
|
LL | sample.iter().collect::<BinaryHeap<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: aborting due to 11 previous errors