Auto merge of #86031 - ssomers:btree_lazy_iterator, r=Mark-Simulacrum

[rust.git] / src / tools / clippy / clippy_lints / src / len_zero.rs

diff --git a/src/tools/clippy/clippy_lints/src/len_zero.rs b/src/tools/clippy/clippy_lints/src/len_zero.rs
index 583514b22f9bf65a01897fa38618d25d910913be..b66d7a9f7294f5844add5ca01daafb0c501283f8 100644 (file)
--- a/src/tools/clippy/clippy_lints/src/len_zero.rs
+++ b/src/tools/clippy/clippy_lints/src/len_zero.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{get_item_name, get_parent_as_impl, is_allowed};
+use clippy_utils::{get_item_name, get_parent_as_impl, is_lint_allowed};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
@@ -18,17 +18,17 @@
 };
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for getting the length of something via `.len()`
+    /// ### What it does
+    /// Checks for getting the length of something via `.len()`
     /// just to compare to zero, and suggests using `.is_empty()` where applicable.
     ///
-    /// **Why is this bad?** Some structures can answer `.is_empty()` much faster
+    /// ### Why is this bad?
+    /// Some structures can answer `.is_empty()` much faster
     /// than calculating their length. So it is good to get into the habit of using
     /// `.is_empty()`, and having it is cheap.
     /// Besides, it makes the intent clearer than a manual comparison in some contexts.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// if x.len() == 0 {
     ///     ..
@@ -52,18 +52,18 @@
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for items that implement `.len()` but not
+    /// ### What it does
+    /// Checks for items that implement `.len()` but not
     /// `.is_empty()`.
     ///
-    /// **Why is this bad?** It is good custom to have both methods, because for
+    /// ### Why is this bad?
+    /// It is good custom to have both methods, because for
     /// some data structures, asking about the length will be a costly operation,
     /// whereas `.is_empty()` can usually answer in constant time. Also it used to
     /// lead to false positives on the [`len_zero`](#len_zero) lint – currently that
     /// lint will ignore such entities.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```ignore
     /// impl X {
     ///     pub fn len(&self) -> usize {
@@ -77,17 +77,17 @@
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for comparing to an empty slice such as `""` or `[]`,
+    /// ### What it does
+    /// Checks for comparing to an empty slice such as `""` or `[]`,
     /// and suggests using `.is_empty()` where applicable.
     ///
-    /// **Why is this bad?** Some structures can answer `.is_empty()` much faster
+    /// ### Why is this bad?
+    /// Some structures can answer `.is_empty()` much faster
     /// than checking for equality. So it is good to get into the habit of using
     /// `.is_empty()`, and having it is cheap.
     /// Besides, it makes the intent clearer than a manual comparison in some contexts.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     ///
     /// ```ignore
     /// if s == "" {
@@ -128,7 +128,7 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
         if_chain! {
-            if item.ident.as_str() == "len";
+            if item.ident.name == sym::len;
             if let ImplItemKind::Fn(sig, _) = &item.kind;
             if sig.decl.implicit_self.has_implicit_self();
             if cx.access_levels.is_exported(item.hir_id());
@@ -139,7 +139,7 @@ fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>)
             if let Some(ty_id) = cx.qpath_res(ty_path, imp.self_ty.hir_id).opt_def_id();
             if let Some(local_id) = ty_id.as_local();
             let ty_hir_id = cx.tcx.hir().local_def_id_to_hir_id(local_id);
-            if !is_allowed(cx, LEN_WITHOUT_IS_EMPTY, ty_hir_id);
+            if !is_lint_allowed(cx, LEN_WITHOUT_IS_EMPTY, ty_hir_id);
             if let Some(output) = parse_len_output(cx, cx.tcx.fn_sig(item.def_id).skip_binder());
             then {
                 let (name, kind) = match cx.tcx.hir().find(ty_hir_id) {
@@ -189,8 +189,8 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
 }
 
 fn check_trait_items(cx: &LateContext<'_>, visited_trait: &Item<'_>, trait_items: &[TraitItemRef]) {
-    fn is_named_self(cx: &LateContext<'_>, item: &TraitItemRef, name: &str) -> bool {
-        item.ident.name.as_str() == name
+    fn is_named_self(cx: &LateContext<'_>, item: &TraitItemRef, name: Symbol) -> bool {
+        item.ident.name == name
             && if let AssocItemKind::Fn { has_self } = item.kind {
                 has_self && { cx.tcx.fn_sig(item.id.def_id).inputs().skip_binder().len() == 1 }
             } else {
@@ -207,7 +207,9 @@ fn fill_trait_set(traitt: DefId, set: &mut DefIdSet, cx: &LateContext<'_>) {
         }
     }
 
-    if cx.access_levels.is_exported(visited_trait.hir_id()) && trait_items.iter().any(|i| is_named_self(cx, i, "len")) {
+    if cx.access_levels.is_exported(visited_trait.hir_id())
+        && trait_items.iter().any(|i| is_named_self(cx, i, sym::len))
+    {
         let mut current_and_super_traits = DefIdSet::default();
         fill_trait_set(visited_trait.def_id.to_def_id(), &mut current_and_super_traits, cx);
 
@@ -401,7 +403,7 @@ fn check_len(
             return;
         }
 
-        if method_name.as_str() == "len" && args.len() == 1 && has_is_empty(cx, &args[0]) {
+        if method_name == sym::len && args.len() == 1 && has_is_empty(cx, &args[0]) {
             let mut applicability = Applicability::MachineApplicable;
             span_lint_and_sugg(
                 cx,