mirror of https://github.com/rust-lang/rust.git
Auto merge of #8992 - kyoto7250:fix_8753, r=flip1995
feat(fix): Do not lint if the target code is inside a loop close #8753 we consider the following code. ```rust fn main() { let vec = vec![1]; let w: Vec<usize> = vec.iter().map(|i| i * i).collect(); // <- once. for i in 0..2 { let _ = w.contains(&i); } } ``` and the clippy will issue the following warning. ```rust warning: avoid using `collect()` when not needed --> src/main.rs:3:51 | 3 | let w: Vec<usize> = vec.iter().map(|i| i * i).collect(); | ^^^^^^^ ... 6 | let _ = w.contains(&i); | -------------- the iterator could be used here instead | = note: `#[warn(clippy::needless_collect)]` on by default = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_collect help: check if the original Iterator contains an element instead of collecting then checking | 3 ~ 4 | 5 | for i in 0..2 { 6 ~ let _ = vec.iter().map(|i| i * i).any(|x| x == i); ``` Rewrite the code as indicated. ```rust fn main() { let vec = vec![1]; for i in 0..2 { let _ = vec.iter().map(|i| i * i).any(|x| x == i); // <- execute `map` every loop. } } ``` this code is valid in the compiler, but, it is different from the code before the rewrite. So, we should not lint, If `collect` is outside of a loop. Thank you in advance. --- changelog: Do not lint if the target code is inside a loop in `needless_collect`
This commit is contained in:
bors
commit
e19a05cbb3
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@ -1,5 +1,6 @@
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use super::NEEDLESS_COLLECT;
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use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
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use clippy_utils::higher;
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use clippy_utils::source::{snippet, snippet_with_applicability};
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use clippy_utils::sugg::Sugg;
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use clippy_utils::ty::is_type_diagnostic_item;
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@ -184,10 +185,19 @@ struct IterFunctionVisitor<'a, 'tcx> {
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impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
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fn visit_block(&mut self, block: &'tcx Block<'tcx>) {
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for (expr, hir_id) in block.stmts.iter().filter_map(get_expr_and_hir_id_from_stmt) {
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if check_loop_kind(expr).is_some() {
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continue;
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}
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self.visit_block_expr(expr, hir_id);
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}
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if let Some(expr) = block.expr {
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self.visit_block_expr(expr, None);
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if let Some(loop_kind) = check_loop_kind(expr) {
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if let LoopKind::Conditional(block_expr) = loop_kind {
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self.visit_block_expr(block_expr, None);
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}
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} else {
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self.visit_block_expr(expr, None);
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}
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}
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}
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@ -264,6 +274,28 @@ impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
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}
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}
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enum LoopKind<'tcx> {
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Conditional(&'tcx Expr<'tcx>),
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Loop,
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}
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fn check_loop_kind<'tcx>(expr: &Expr<'tcx>) -> Option<LoopKind<'tcx>> {
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if let Some(higher::WhileLet { let_expr, .. }) = higher::WhileLet::hir(expr) {
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return Some(LoopKind::Conditional(let_expr));
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}
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if let Some(higher::While { condition, .. }) = higher::While::hir(expr) {
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return Some(LoopKind::Conditional(condition));
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}
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if let Some(higher::ForLoop { arg, .. }) = higher::ForLoop::hir(expr) {
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return Some(LoopKind::Conditional(arg));
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}
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if let ExprKind::Loop { .. } = expr.kind {
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return Some(LoopKind::Loop);
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}
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None
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}
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impl<'tcx> IterFunctionVisitor<'_, 'tcx> {
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fn visit_block_expr(&mut self, expr: &'tcx Expr<'tcx>, hir_id: Option<HirId>) {
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self.current_statement_hir_id = hir_id;
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@ -413,11 +413,13 @@ fn check_rustfix_coverage() {
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if let Ok(missing_coverage_contents) = std::fs::read_to_string(missing_coverage_path) {
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assert!(RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS.iter().is_sorted_by_key(Path::new));
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for rs_path in missing_coverage_contents.lines() {
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if Path::new(rs_path).starts_with("tests/ui/crashes") {
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for rs_file in missing_coverage_contents.lines() {
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let rs_path = Path::new(rs_file);
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if rs_path.starts_with("tests/ui/crashes") {
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continue;
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}
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let filename = Path::new(rs_path).strip_prefix("tests/ui/").unwrap();
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assert!(rs_path.starts_with("tests/ui/"), "{:?}", rs_file);
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let filename = rs_path.strip_prefix("tests/ui/").unwrap();
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assert!(
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RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS
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.binary_search_by_key(&filename, Path::new)
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@ -425,7 +427,7 @@ fn check_rustfix_coverage() {
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"`{}` runs `MachineApplicable` diagnostics but is missing a `run-rustfix` annotation. \
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Please either add `// run-rustfix` at the top of the file or add the file to \
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`RUSTFIX_COVERAGE_KNOWN_EXCEPTIONS` in `tests/compile-test.rs`.",
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rs_path,
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rs_file,
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);
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}
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}
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@ -112,3 +112,192 @@ fn allow_test() {
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let v = [1].iter().collect::<Vec<_>>();
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v.into_iter().collect::<HashSet<_>>();
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}
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mod issue_8553 {
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fn test_for() {
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let vec = vec![1, 2];
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let w: Vec<usize> = vec.iter().map(|i| i * i).collect();
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for i in 0..2 {
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// Do not lint, because this method call is in the loop
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w.contains(&i);
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}
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for i in 0..2 {
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let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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// Do lint
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y.contains(&i);
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for j in 0..2 {
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// Do not lint, because this method call is in the loop
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z.contains(&j);
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}
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}
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// Do not lint, because this variable is used.
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w.contains(&0);
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}
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fn test_while() {
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let vec = vec![1, 2];
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let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut n = 0;
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while n > 1 {
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// Do not lint, because this method call is in the loop
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x.contains(&n);
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n += 1;
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}
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while n > 2 {
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let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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// Do lint
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y.contains(&n);
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n += 1;
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while n > 4 {
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// Do not lint, because this method call is in the loop
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z.contains(&n);
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n += 1;
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}
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}
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}
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fn test_loop() {
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let vec = vec![1, 2];
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let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut n = 0;
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loop {
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if n < 1 {
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// Do not lint, because this method call is in the loop
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x.contains(&n);
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n += 1;
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} else {
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break;
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}
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}
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loop {
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if n < 2 {
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let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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// Do lint
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y.contains(&n);
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n += 1;
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loop {
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if n < 4 {
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// Do not lint, because this method call is in the loop
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z.contains(&n);
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n += 1;
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} else {
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break;
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}
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}
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} else {
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break;
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}
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}
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}
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fn test_while_let() {
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let vec = vec![1, 2];
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let x: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let optional = Some(0);
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let mut n = 0;
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while let Some(value) = optional {
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if n < 1 {
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// Do not lint, because this method call is in the loop
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x.contains(&n);
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n += 1;
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} else {
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break;
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}
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}
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while let Some(value) = optional {
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let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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if n < 2 {
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// Do lint
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y.contains(&n);
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n += 1;
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} else {
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break;
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}
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while let Some(value) = optional {
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if n < 4 {
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// Do not lint, because this method call is in the loop
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z.contains(&n);
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n += 1;
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} else {
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break;
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}
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}
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}
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}
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fn test_if_cond() {
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let vec = vec![1, 2];
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let v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let w = v.iter().collect::<Vec<_>>();
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// Do lint
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for _ in 0..w.len() {
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todo!();
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}
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}
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fn test_if_cond_false_case() {
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let vec = vec![1, 2];
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let v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let w = v.iter().collect::<Vec<_>>();
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// Do not lint, because w is used.
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for _ in 0..w.len() {
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todo!();
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}
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w.len();
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}
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fn test_while_cond() {
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let mut vec = vec![1, 2];
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let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut w = v.iter().collect::<Vec<_>>();
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// Do lint
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while 1 == w.len() {
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todo!();
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}
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}
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fn test_while_cond_false_case() {
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let mut vec = vec![1, 2];
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let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut w = v.iter().collect::<Vec<_>>();
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// Do not lint, because w is used.
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while 1 == w.len() {
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todo!();
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}
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w.len();
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}
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fn test_while_let_cond() {
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let mut vec = vec![1, 2];
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let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut w = v.iter().collect::<Vec<_>>();
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// Do lint
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while let Some(i) = Some(w.len()) {
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todo!();
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}
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}
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fn test_while_let_cond_false_case() {
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let mut vec = vec![1, 2];
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let mut v: Vec<usize> = vec.iter().map(|i| i * i).collect();
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let mut w = v.iter().collect::<Vec<_>>();
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// Do not lint, because w is used.
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while let Some(i) = Some(w.len()) {
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todo!();
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}
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w.len();
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}
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}
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@ -125,5 +125,122 @@ LL ~
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LL ~ sample.iter().count()
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error: aborting due to 9 previous errors
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:127:59
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LL | let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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| ^^^^^^^
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...
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LL | y.contains(&i);
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| -------------- the iterator could be used here instead
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|
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help: check if the original Iterator contains an element instead of collecting then checking
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|
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LL ~
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LL | let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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LL | // Do lint
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LL ~ vec.iter().map(|k| k * k).any(|x| x == i);
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:152:59
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LL | let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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| ^^^^^^^
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...
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LL | y.contains(&n);
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| -------------- the iterator could be used here instead
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|
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help: check if the original Iterator contains an element instead of collecting then checking
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|
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LL ~
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LL | let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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LL | // Do lint
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LL ~ vec.iter().map(|k| k * k).any(|x| x == n);
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:181:63
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|
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LL | let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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| ^^^^^^^
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...
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LL | y.contains(&n);
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| -------------- the iterator could be used here instead
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|
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help: check if the original Iterator contains an element instead of collecting then checking
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|
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LL ~
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LL | let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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LL | // Do lint
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LL ~ vec.iter().map(|k| k * k).any(|x| x == n);
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:217:59
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|
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LL | let y: Vec<usize> = vec.iter().map(|k| k * k).collect();
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| ^^^^^^^
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...
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LL | y.contains(&n);
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| -------------- the iterator could be used here instead
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|
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help: check if the original Iterator contains an element instead of collecting then checking
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|
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LL ~
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LL | let z: Vec<usize> = vec.iter().map(|k| k * k).collect();
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LL | if n < 2 {
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LL | // Do lint
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LL ~ vec.iter().map(|k| k * k).any(|x| x == n);
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:242:26
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|
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LL | let w = v.iter().collect::<Vec<_>>();
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| ^^^^^^^
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LL | // Do lint
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LL | for _ in 0..w.len() {
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| ------- the iterator could be used here instead
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|
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help: take the original Iterator's count instead of collecting it and finding the length
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|
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LL ~
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LL | // Do lint
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LL ~ for _ in 0..v.iter().count() {
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:264:30
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|
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LL | let mut w = v.iter().collect::<Vec<_>>();
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| ^^^^^^^
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LL | // Do lint
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LL | while 1 == w.len() {
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| ------- the iterator could be used here instead
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|
|
||||
help: take the original Iterator's count instead of collecting it and finding the length
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|
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LL ~
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LL | // Do lint
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LL ~ while 1 == v.iter().count() {
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|
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error: avoid using `collect()` when not needed
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--> $DIR/needless_collect_indirect.rs:286:30
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|
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LL | let mut w = v.iter().collect::<Vec<_>>();
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| ^^^^^^^
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LL | // Do lint
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||||
LL | while let Some(i) = Some(w.len()) {
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||||
| ------- the iterator could be used here instead
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|
|
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help: take the original Iterator's count instead of collecting it and finding the length
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||||
|
|
||||
LL ~
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LL | // Do lint
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||||
LL ~ while let Some(i) = Some(v.iter().count()) {
|
||||
|
|
||||
|
||||
error: aborting due to 16 previous errors
|
||||
|
||||
|
|
|
|||
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