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extend needless_collect (#14361)

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changelog: [`needless_collect`]: extend needless_collect to lint more
cases

Fix #14350
This commit is contained in:
Jason Newcomb 2025-10-31 19:12:13 +00:00 • committed by GitHub
commit e6298692a5
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GPG key ID: B5690EEEBB952194
4 changed files with 52 additions and 29 deletions
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33
clippy_lints/src/methods/needless_collect.rs
View file

@ -38,11 +38,14 @@ pub(super) fn check<'tcx>(
Node::Expr(parent) => {
check_collect_into_intoiterator(cx, parent, collect_expr, call_span, iter_expr);
let sugg: String;
let mut app;
if let ExprKind::MethodCall(name, _, args @ ([] | [_]), _) = parent.kind {
let mut app = Applicability::MachineApplicable;
app = Applicability::MachineApplicable;
let collect_ty = cx.typeck_results().expr_ty(collect_expr);
let sugg: String = match name.ident.name {
sugg = match name.ident.name {
sym::len => {
if let Some(adt) = collect_ty.ty_adt_def()
&& matches!(
@ -78,17 +81,23 @@ pub(super) fn check<'tcx>(
},
_ => return,
};
span_lint_and_sugg(
cx,
NEEDLESS_COLLECT,
call_span.with_hi(parent.span.hi()),
NEEDLESS_COLLECT_MSG,
"replace with",
sugg,
app,
);
} else if let ExprKind::Index(_, index, _) = parent.kind {
app = Applicability::MaybeIncorrect;
let snip = snippet_with_applicability(cx, index.span, "_", &mut app);
sugg = format!("nth({snip}).unwrap()");
} else {
return;
}
span_lint_and_sugg(
cx,
NEEDLESS_COLLECT,
call_span.with_hi(parent.span.hi()),
NEEDLESS_COLLECT_MSG,
"replace with",
sugg,
app,
);
},
Node::LetStmt(l) => {
if let PatKind::Binding(BindingMode::NONE | BindingMode::MUT, id, _, None) = l.pat.kind

4
tests/ui/needless_collect.fixed
View file

@ -20,6 +20,10 @@ fn main() {
}
sample.iter().cloned().any(|x| x == 1);
//~^ needless_collect
let _ = sample.iter().cloned().nth(1).unwrap();
//~^ needless_collect
// #7164 HashMap's and BTreeMap's `len` usage should not be linted
sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().len();
sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().len();

4
tests/ui/needless_collect.rs
View file

@ -20,6 +20,10 @@ fn main() {
}
sample.iter().cloned().collect::<Vec<_>>().contains(&1);
//~^ needless_collect
let _ = sample.iter().cloned().collect::<Vec<_>>()[1];
//~^ needless_collect
// #7164 HashMap's and BTreeMap's `len` usage should not be linted
sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().len();
sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().len();

40
tests/ui/needless_collect.stderr
View file

@ -20,100 +20,106 @@ LL | sample.iter().cloned().collect::<Vec<_>>().contains(&1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == 1)`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:27:35
--> tests/ui/needless_collect.rs:24:36
|
LL | let _ = sample.iter().cloned().collect::<Vec<_>>()[1];
| ^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `nth(1).unwrap()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:31:35
|
LL | sample.iter().map(|x| (x, x)).collect::<HashMap<_, _>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:29:35
--> tests/ui/needless_collect.rs:33:35
|
LL | sample.iter().map(|x| (x, x)).collect::<BTreeMap<_, _>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:37:19
--> tests/ui/needless_collect.rs:41:19
|
LL | sample.iter().collect::<LinkedList<_>>().len();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:39:19
--> tests/ui/needless_collect.rs:43:19
|
LL | sample.iter().collect::<LinkedList<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:41:28
--> tests/ui/needless_collect.rs:45:28
|
LL | sample.iter().cloned().collect::<LinkedList<_>>().contains(&1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == 1)`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:43:19
--> tests/ui/needless_collect.rs:47:19
|
LL | sample.iter().collect::<LinkedList<_>>().contains(&&1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == &1)`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:47:19
--> tests/ui/needless_collect.rs:51:19
|
LL | sample.iter().collect::<BinaryHeap<_>>().len();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:49:19
--> tests/ui/needless_collect.rs:53:19
|
LL | sample.iter().collect::<BinaryHeap<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:55:27
--> tests/ui/needless_collect.rs:59:27
|
LL | let _ = sample.iter().collect::<HashSet<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:57:27
--> tests/ui/needless_collect.rs:61:27
|
LL | let _ = sample.iter().collect::<HashSet<_>>().contains(&&0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == &0)`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:80:27
--> tests/ui/needless_collect.rs:84:27
|
LL | let _ = sample.iter().collect::<VecWrapper<_>>().is_empty();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:82:27
--> tests/ui/needless_collect.rs:86:27
|
LL | let _ = sample.iter().collect::<VecWrapper<_>>().contains(&&0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `any(|x| x == &0)`
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:87:40
--> tests/ui/needless_collect.rs:91:40
|
LL | Vec::<u8>::new().extend((0..10).collect::<Vec<_>>());
| ^^^^^^^^^^^^^^^^^^^^ help: remove this call
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:89:20
--> tests/ui/needless_collect.rs:93:20
|
LL | foo((0..10).collect::<Vec<_>>());
| ^^^^^^^^^^^^^^^^^^^^ help: remove this call
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:91:49
--> tests/ui/needless_collect.rs:95:49
|
LL | bar((0..10).collect::<Vec<_>>(), (0..10).collect::<Vec<_>>());
| ^^^^^^^^^^^^^^^^^^^^ help: remove this call
error: avoid using `collect()` when not needed
--> tests/ui/needless_collect.rs:93:37
--> tests/ui/needless_collect.rs:97:37
|
LL | baz((0..10), (), ('a'..='z').collect::<Vec<_>>())
| ^^^^^^^^^^^^^^^^^^^^ help: remove this call
error: aborting due to 19 previous errors
error: aborting due to 20 previous errors