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Auto merge of rust-lang#8203 - pmnoxx:piotr-next-lint, r=llogiq
New lint: `iter_overeager_cloned` Closes rust-lang#8202 changelog: New lint: [`iter_overeager_cloned`]
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,62 @@ | ||
| use clippy_utils::diagnostics::span_lint_and_sugg; | ||
| use clippy_utils::source::snippet; | ||
| use clippy_utils::ty::{get_iterator_item_ty, is_copy}; | ||
| use itertools::Itertools; | ||
| use rustc_errors::Applicability; | ||
| use rustc_hir as hir; | ||
| use rustc_lint::LateContext; | ||
| use rustc_middle::ty; | ||
| use std::ops::Not; | ||
|
|
||
| use super::ITER_OVEREAGER_CLONED; | ||
| use crate::redundant_clone::REDUNDANT_CLONE; | ||
|
|
||
| /// lint overeager use of `cloned()` for `Iterator`s | ||
| pub(super) fn check<'tcx>( | ||
| cx: &LateContext<'tcx>, | ||
| expr: &'tcx hir::Expr<'_>, | ||
| recv: &'tcx hir::Expr<'_>, | ||
| name: &str, | ||
| map_arg: &[hir::Expr<'_>], | ||
| ) { | ||
| // Check if it's iterator and get type associated with `Item`. | ||
| let inner_ty = match get_iterator_item_ty(cx, cx.typeck_results().expr_ty_adjusted(recv)) { | ||
| Some(ty) => ty, | ||
| _ => return, | ||
| }; | ||
|
|
||
| match inner_ty.kind() { | ||
| ty::Ref(_, ty, _) if !is_copy(cx, ty) => {}, | ||
| _ => return, | ||
| }; | ||
|
|
||
| let (lint, preserve_cloned) = match name { | ||
| "count" => (REDUNDANT_CLONE, false), | ||
| _ => (ITER_OVEREAGER_CLONED, true), | ||
| }; | ||
| let wildcard_params = map_arg.is_empty().not().then(|| "...").unwrap_or_default(); | ||
| let msg = format!( | ||
| "called `cloned().{}({})` on an `Iterator`. It may be more efficient to call `{}({}){}` instead", | ||
| name, | ||
| wildcard_params, | ||
| name, | ||
| wildcard_params, | ||
| preserve_cloned.then(|| ".cloned()").unwrap_or_default(), | ||
| ); | ||
|
|
||
| span_lint_and_sugg( | ||
| cx, | ||
| lint, | ||
| expr.span, | ||
| &msg, | ||
| "try this", | ||
| format!( | ||
| "{}.{}({}){}", | ||
| snippet(cx, recv.span, ".."), | ||
| name, | ||
| map_arg.iter().map(|a| snippet(cx, a.span, "..")).join(", "), | ||
| preserve_cloned.then(|| ".cloned()").unwrap_or_default(), | ||
| ), | ||
| Applicability::MachineApplicable, | ||
| ); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,45 @@ | ||
| // run-rustfix | ||
| #![warn(clippy::iter_overeager_cloned, clippy::redundant_clone, clippy::filter_next)] | ||
|
|
||
| fn main() { | ||
| let vec = vec!["1".to_string(), "2".to_string(), "3".to_string()]; | ||
|
|
||
| let _: Option<String> = vec.iter().last().cloned(); | ||
|
|
||
| let _: Option<String> = vec.iter().chain(vec.iter()).next().cloned(); | ||
|
|
||
| let _: usize = vec.iter().filter(|x| x == &"2").count(); | ||
|
|
||
| let _: Vec<_> = vec.iter().take(2).cloned().collect(); | ||
|
|
||
| let _: Vec<_> = vec.iter().skip(2).cloned().collect(); | ||
|
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||
| let _ = vec.iter().filter(|x| x == &"2").nth(2).cloned(); | ||
|
|
||
| let _ = [Some(Some("str".to_string())), Some(Some("str".to_string()))] | ||
| .iter().flatten().cloned(); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().filter(|x| x.starts_with('2')); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().map(|x| x.len()); | ||
|
|
||
| // This would fail if changed. | ||
| let _ = vec.iter().cloned().map(|x| x + "2"); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().find(|x| x == "2"); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().for_each(|x| assert!(!x.is_empty())); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().all(|x| x.len() == 1); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().any(|x| x.len() == 1); | ||
|
|
||
| // Should probably stay as it is. | ||
| let _ = [0, 1, 2, 3, 4].iter().cloned().take(10); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,47 @@ | ||
| // run-rustfix | ||
| #![warn(clippy::iter_overeager_cloned, clippy::redundant_clone, clippy::filter_next)] | ||
|
|
||
| fn main() { | ||
| let vec = vec!["1".to_string(), "2".to_string(), "3".to_string()]; | ||
|
|
||
| let _: Option<String> = vec.iter().cloned().last(); | ||
|
|
||
| let _: Option<String> = vec.iter().chain(vec.iter()).cloned().next(); | ||
|
|
||
| let _: usize = vec.iter().filter(|x| x == &"2").cloned().count(); | ||
|
|
||
| let _: Vec<_> = vec.iter().cloned().take(2).collect(); | ||
|
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||
| let _: Vec<_> = vec.iter().cloned().skip(2).collect(); | ||
|
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||
| let _ = vec.iter().filter(|x| x == &"2").cloned().nth(2); | ||
|
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||
| let _ = [Some(Some("str".to_string())), Some(Some("str".to_string()))] | ||
| .iter() | ||
| .cloned() | ||
| .flatten(); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().filter(|x| x.starts_with('2')); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().map(|x| x.len()); | ||
|
|
||
| // This would fail if changed. | ||
| let _ = vec.iter().cloned().map(|x| x + "2"); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().find(|x| x == "2"); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().for_each(|x| assert!(!x.is_empty())); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().all(|x| x.len() == 1); | ||
|
|
||
| // Not implemented yet | ||
| let _ = vec.iter().cloned().any(|x| x.len() == 1); | ||
|
|
||
| // Should probably stay as it is. | ||
| let _ = [0, 1, 2, 3, 4].iter().cloned().take(10); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,58 @@ | ||
| error: called `cloned().last()` on an `Iterator`. It may be more efficient to call `last().cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:7:29 | ||
| | | ||
| LL | let _: Option<String> = vec.iter().cloned().last(); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().last().cloned()` | ||
| | | ||
| = note: `-D clippy::iter-overeager-cloned` implied by `-D warnings` | ||
|
|
||
| error: called `cloned().next()` on an `Iterator`. It may be more efficient to call `next().cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:9:29 | ||
| | | ||
| LL | let _: Option<String> = vec.iter().chain(vec.iter()).cloned().next(); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().chain(vec.iter()).next().cloned()` | ||
|
|
||
| error: called `cloned().count()` on an `Iterator`. It may be more efficient to call `count()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:11:20 | ||
| | | ||
| LL | let _: usize = vec.iter().filter(|x| x == &"2").cloned().count(); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().filter(|x| x == &"2").count()` | ||
| | | ||
| = note: `-D clippy::redundant-clone` implied by `-D warnings` | ||
|
|
||
| error: called `cloned().take(...)` on an `Iterator`. It may be more efficient to call `take(...).cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:13:21 | ||
| | | ||
| LL | let _: Vec<_> = vec.iter().cloned().take(2).collect(); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().take(2).cloned()` | ||
|
|
||
| error: called `cloned().skip(...)` on an `Iterator`. It may be more efficient to call `skip(...).cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:15:21 | ||
| | | ||
| LL | let _: Vec<_> = vec.iter().cloned().skip(2).collect(); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().skip(2).cloned()` | ||
|
|
||
| error: called `cloned().nth(...)` on an `Iterator`. It may be more efficient to call `nth(...).cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:17:13 | ||
| | | ||
| LL | let _ = vec.iter().filter(|x| x == &"2").cloned().nth(2); | ||
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `vec.iter().filter(|x| x == &"2").nth(2).cloned()` | ||
|
|
||
| error: called `cloned().flatten()` on an `Iterator`. It may be more efficient to call `flatten().cloned()` instead | ||
| --> $DIR/iter_overeager_cloned.rs:19:13 | ||
| | | ||
| LL | let _ = [Some(Some("str".to_string())), Some(Some("str".to_string()))] | ||
| | _____________^ | ||
| LL | | .iter() | ||
| LL | | .cloned() | ||
| LL | | .flatten(); | ||
| | |__________________^ | ||
| | | ||
| help: try this | ||
| | | ||
| LL ~ let _ = [Some(Some("str".to_string())), Some(Some("str".to_string()))] | ||
| LL ~ .iter().flatten().cloned(); | ||
| | | ||
|
|
||
| error: aborting due to 7 previous errors | ||
|
|