new lint to detect inefficient iter().any()

CHANGELOG.md

@@ -6020,6 +6020,7 @@ Released 2018-09-13
 [`size_of_in_element_count`]: https://rust-lang.github.io/rust-clippy/master/index.html#size_of_in_element_count
 [`size_of_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#size_of_ref
 [`skip_while_next`]: https://rust-lang.github.io/rust-clippy/master/index.html#skip_while_next
+[`slice_iter_any`]: https://rust-lang.github.io/rust-clippy/master/index.html#slice_iter_any
 [`slow_vector_initialization`]: https://rust-lang.github.io/rust-clippy/master/index.html#slow_vector_initialization
 [`stable_sort_primitive`]: https://rust-lang.github.io/rust-clippy/master/index.html#stable_sort_primitive
 [`std_instead_of_alloc`]: https://rust-lang.github.io/rust-clippy/master/index.html#std_instead_of_alloc

clippy_lints/src/declared_lints.rs

@@ -464,6 +464,7 @@ pub static LINTS: &[&crate::LintInfo] = &[
     crate::methods::SHOULD_IMPLEMENT_TRAIT_INFO,
     crate::methods::SINGLE_CHAR_ADD_STR_INFO,
     crate::methods::SKIP_WHILE_NEXT_INFO,
+    crate::methods::SLICE_ITER_ANY_INFO,
     crate::methods::STABLE_SORT_PRIMITIVE_INFO,
     crate::methods::STRING_EXTEND_CHARS_INFO,
     crate::methods::STRING_LIT_CHARS_ANY_INFO,

clippy_lints/src/methods/mod.rs

@@ -100,6 +100,7 @@ mod single_char_add_str;
 mod single_char_insert_string;
 mod single_char_push_string;
 mod skip_while_next;
+mod slice_iter_any;
 mod stable_sort_primitive;
 mod str_split;
 mod str_splitn;
@@ -4284,6 +4285,31 @@ declare_clippy_lint! {
     "map of a trivial closure (not dependent on parameter) over a range"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for usage of `iter().any()` on numeric slices when it can be replaced with `contains()` and suggests doing so.
+    ///
+    /// ### Why is this bad?
+    /// `contains()` on numeric slices is faster than `iter().any()`.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// fn foo(values: &[u8]) -> bool {
+    ///    values.iter().any(|&v| v == 10)
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// fn foo(values: &[u8]) -> bool {
+    ///    values.contains(&10)
+    /// }
+    /// ```
+    #[clippy::version = "1.85.0"]
+    pub SLICE_ITER_ANY,
+    perf,
+    "detect use of `iter().any()` on numeric slices and suggest using `contains()`"
+}
+
 pub struct Methods {
     avoid_breaking_exported_api: bool,
     msrv: Msrv,
@@ -4449,6 +4475,7 @@ impl_lint_pass!(Methods => [
     MAP_ALL_ANY_IDENTITY,
     MAP_WITH_UNUSED_ARGUMENT_OVER_RANGES,
     UNNECESSARY_MAP_OR,
+    SLICE_ITER_ANY,
 ]);
 
 /// Extracts a method call name, args, and `Span` of the method name.
@@ -4683,6 +4710,7 @@ impl Methods {
                 ("any", [arg]) => {
                     unused_enumerate_index::check(cx, expr, recv, arg);
                     needless_character_iteration::check(cx, expr, recv, arg, false);
+                    slice_iter_any::check(cx, expr, &self.msrv);
                     match method_call(recv) {
                         Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
                             cx,

clippy_lints/src/methods/slice_iter_any.rs

@@ -0,0 +1,66 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::msrvs::Msrv;
+use rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self};
+use rustc_session::RustcVersion;
+use rustc_span::source_map::Spanned;
+
+use super::{SLICE_ITER_ANY, method_call};
+
+pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, msrv: &Msrv) {
+    if !expr.span.from_expansion()
+    // any()
+    && let Some((name, recv, args, _, _)) = method_call(expr)
+    && name == "any"
+    // check if `iter().any()` can be replaced with `contains()`
+    && args.len() == 1
+    && let ExprKind::Closure(closure) = args[0].kind
+    && let body = cx.tcx.hir().body(closure.body)
+    && let ExprKind::Binary(op, lhs, rhs) = body.value.kind
+    && can_replace_with_contains(op, lhs, rhs)
+    // iter()
+    && let Some((name, recv, _, _, _)) = method_call(recv)
+    && name == "iter"
+    {
+        let ref_type = cx.typeck_results().expr_ty_adjusted(recv);
+
+        match ref_type.kind() {
+            ty::Ref(_, inner_type, _) if inner_type.is_slice() => {
+                // check if the receiver is a numeric slice
+                if let ty::Slice(slice_type) = inner_type.kind()
+                    && ((slice_type.to_string() == "u8" || slice_type.to_string() == "i8")
+                        || (slice_type.is_numeric()
+                            && msrv.meets(RustcVersion {
+                                major: 1,
+                                minor: 84,
+                                patch: 0,
+                            })))
+                {
+                    span_lint(
+                        cx,
+                        SLICE_ITER_ANY,
+                        expr.span,
+                        "using `contains()` instead of `iter().any()` is more efficient",
+                    );
+                }
+            },
+            _ => {},
+        }
+    }
+}
+
+fn can_replace_with_contains(op: Spanned<BinOpKind>, lhs: &Expr<'_>, rhs: &Expr<'_>) -> bool {
+    matches!(
+        (op.node, &lhs.kind, &rhs.kind),
+        (
+            BinOpKind::Eq,
+            ExprKind::Path(_) | ExprKind::Unary(_, _),
+            ExprKind::Lit(_) | ExprKind::Path(_)
+        ) | (
+            BinOpKind::Eq,
+            ExprKind::Lit(_),
+            ExprKind::Path(_) | ExprKind::Unary(_, _)
+        )
+    )
+}

tests/ui/needless_collect.fixed

@@ -1,4 +1,10 @@
-#![allow(unused, clippy::needless_if, clippy::suspicious_map, clippy::iter_count)]
+#![allow(
+    unused,
+    clippy::needless_if,
+    clippy::suspicious_map,
+    clippy::iter_count,
+    clippy::slice_iter_any
+)]
 
 use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
 

tests/ui/needless_collect.rs

@@ -1,4 +1,10 @@
-#![allow(unused, clippy::needless_if, clippy::suspicious_map, clippy::iter_count)]
+#![allow(
+    unused,
+    clippy::needless_if,
+    clippy::suspicious_map,
+    clippy::iter_count,
+    clippy::slice_iter_any
+)]
 
 use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, LinkedList};
 

tests/ui/needless_collect.stderr

@@ -1,5 +1,5 @@
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:9:29
+  --> tests/ui/needless_collect.rs:15:29
    |
 LL |     let len = sample.iter().collect::<Vec<_>>().len();
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
@@ -8,109 +8,109 @@ LL |     let len = sample.iter().collect::<Vec<_>>().len();
    = help: to override `-D warnings` add `#[allow(clippy::needless_collect)]`
 
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:10:22
+  --> tests/ui/needless_collect.rs:16:22
    |
 LL |     if sample.iter().collect::<Vec<_>>().is_empty() {
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `next().is_none()`
 
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:13:28
+  --> tests/ui/needless_collect.rs:19:28
    |
 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:18:35
+  --> tests/ui/needless_collect.rs:24:35
    |
 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:19:35
+  --> tests/ui/needless_collect.rs:25:35
    |
 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:26:19
+  --> tests/ui/needless_collect.rs:32:19
    |
 LL |     sample.iter().collect::<LinkedList<_>>().len();
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
 
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:27:19
+  --> tests/ui/needless_collect.rs:33:19
    |
 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:28:28
+  --> tests/ui/needless_collect.rs:34:28
    |
 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:29:19
+  --> tests/ui/needless_collect.rs:35:19
    |
 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:32:19
+  --> tests/ui/needless_collect.rs:38:19
    |
 LL |     sample.iter().collect::<BinaryHeap<_>>().len();
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `count()`
 
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:33:19
+  --> tests/ui/needless_collect.rs:39:19
    |
 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:38:27
+  --> tests/ui/needless_collect.rs:44:27
    |
 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:39:27
+  --> tests/ui/needless_collect.rs:45:27
    |
 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:61:27
+  --> tests/ui/needless_collect.rs:67:27
    |
 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:62:27
+  --> tests/ui/needless_collect.rs:68:27
    |
 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:66:40
+  --> tests/ui/needless_collect.rs:72:40
    |
 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:67:20
+  --> tests/ui/needless_collect.rs:73:20
    |
 LL |         foo((0..10).collect::<Vec<_>>());
    |                    ^^^^^^^^^^^^^^^^^^^^ help: remove this call
 
 error: avoid using `collect()` when not needed
-  --> tests/ui/needless_collect.rs:68:49
+  --> tests/ui/needless_collect.rs:74:49
    |
 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:69:37
+  --> tests/ui/needless_collect.rs:75:37
    |
 LL |         baz((0..10), (), ('a'..='z').collect::<Vec<_>>())
    |                                     ^^^^^^^^^^^^^^^^^^^^ help: remove this call

tests/ui/search_is_some_fixable_none.fixed

@@ -1,4 +1,4 @@
-#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec)]
+#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec, clippy::slice_iter_any)]
 #![warn(clippy::search_is_some)]
 
 fn main() {

tests/ui/search_is_some_fixable_none.rs

@@ -1,4 +1,4 @@
-#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec)]
+#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec, clippy::slice_iter_any)]
 #![warn(clippy::search_is_some)]
 
 fn main() {

tests/ui/search_is_some_fixable_some.fixed

@@ -1,4 +1,4 @@
-#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec)]
+#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec, clippy::slice_iter_any)]
 #![warn(clippy::search_is_some)]
 
 fn main() {

tests/ui/search_is_some_fixable_some.rs

@@ -1,4 +1,4 @@
-#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec)]
+#![allow(dead_code, clippy::explicit_auto_deref, clippy::useless_vec, clippy::slice_iter_any)]
 #![warn(clippy::search_is_some)]
 
 fn main() {