rust-lang · samueltardieu · May 20, 2025
diff --git a/clippy_lints/src/arbitrary_source_item_ordering.rs b/clippy_lints/src/arbitrary_source_item_ordering.rs
@@ -204,7 +204,7 @@ impl ArbitrarySourceItemOrdering {
                 self.assoc_types_order
             ),
             Some(before_item.span),
-            format!("should be placed before `{}`", before_item.ident.as_str(),),
+            format!("should be placed before `{}`", before_item.ident.name),
         );
     }
 
@@ -216,7 +216,7 @@ impl ArbitrarySourceItemOrdering {
             ident.span,
             "incorrect ordering of items (must be alphabetically ordered)",
             Some(before_ident.span),
-            format!("should be placed before `{}`", before_ident.as_str(),),
+            format!("should be placed before `{}`", before_ident.name),
         );
     }
 
@@ -228,7 +228,7 @@ impl ArbitrarySourceItemOrdering {
         };
 
         let (before_span, note) = if let Some(ident) = before_item.kind.ident() {
-            (ident.span, format!("should be placed before `{}`", ident.as_str(),))
+            (ident.span, format!("should be placed before `{}`", ident.name))
         } else {
             (
                 before_item.span,
@@ -255,7 +255,7 @@ impl ArbitrarySourceItemOrdering {
                 self.assoc_types_order
             ),
             Some(before_item.span),
-            format!("should be placed before `{}`", before_item.ident.as_str(),),
+            format!("should be placed before `{}`", before_item.ident.name),
         );
     }
 }

diff --git a/clippy_lints/src/attrs/duplicated_attributes.rs b/clippy_lints/src/attrs/duplicated_attributes.rs
@@ -1,18 +1,21 @@
 use super::DUPLICATED_ATTRIBUTES;
 use clippy_utils::diagnostics::span_lint_and_then;
+use itertools::Itertools;
 use rustc_ast::{Attribute, MetaItem};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_lint::EarlyContext;
-use rustc_span::{Span, sym};
+use rustc_span::{Span, Symbol, sym};
 use std::collections::hash_map::Entry;
 
 fn emit_if_duplicated(
     cx: &EarlyContext<'_>,
     attr: &MetaItem,
     attr_paths: &mut FxHashMap<String, Span>,
-    complete_path: String,
+    parent: &[Symbol],
+    complete_path: impl FnOnce(&str) -> String,
 ) {
-    match attr_paths.entry(complete_path) {
+    let parent = parent.iter().join(":");
+    match attr_paths.entry(complete_path(&parent)) {
         Entry::Vacant(v) => {
             v.insert(attr.span);
         },
@@ -29,7 +32,7 @@ fn check_duplicated_attr(
     cx: &EarlyContext<'_>,
     attr: &MetaItem,
     attr_paths: &mut FxHashMap<String, Span>,
-    parent: &mut Vec<String>,
+    parent: &mut Vec<Symbol>,
 ) {
     if attr.span.from_expansion() {
         return;
@@ -43,25 +46,27 @@ fn check_duplicated_attr(
         return;
     }
     if let Some(direct_parent) = parent.last()
-        && direct_parent == sym::cfg_trace.as_str()
+        && *direct_parent == sym::cfg_trace
         && [sym::all, sym::not, sym::any].contains(&name)
     {
         // FIXME: We don't correctly check `cfg`s for now, so if it's more complex than just a one
         // level `cfg`, we leave.
         return;
     }
     if let Some(value) = attr.value_str() {
-        emit_if_duplicated(cx, attr, attr_paths, format!("{}:{name}={value}", parent.join(":")));
+        emit_if_duplicated(cx, attr, attr_paths, parent, |parent| {
+            format!("{parent}:{name}={value}")
+        });
     } else if let Some(sub_attrs) = attr.meta_item_list() {
-        parent.push(name.as_str().to_string());
+        parent.push(name);
         for sub_attr in sub_attrs {
             if let Some(meta) = sub_attr.meta_item() {
                 check_duplicated_attr(cx, meta, attr_paths, parent);
             }
         }
         parent.pop();
     } else {
-        emit_if_duplicated(cx, attr, attr_paths, format!("{}:{name}", parent.join(":")));
+        emit_if_duplicated(cx, attr, attr_paths, parent, |parent| format!("{parent}:{name}"));
     }
 }
 

diff --git a/clippy_lints/src/booleans.rs b/clippy_lints/src/booleans.rs
@@ -1,10 +1,10 @@
 use clippy_config::Conf;
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
-use clippy_utils::eq_expr_value;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::SpanRangeExt;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::{eq_expr_value, sym};
 use rustc_ast::ast::LitKind;
 use rustc_attr_parsing::RustcVersion;
 use rustc_errors::Applicability;
@@ -13,7 +13,7 @@ use rustc_hir::{BinOpKind, Body, Expr, ExprKind, FnDecl, UnOp};
 use rustc_lint::{LateContext, LateLintPass, Level};
 use rustc_session::impl_lint_pass;
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Span, SyntaxContext, sym};
+use rustc_span::{Span, Symbol, SyntaxContext};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -73,10 +73,10 @@ declare_clippy_lint! {
 }
 
 // For each pairs, both orders are considered.
-const METHODS_WITH_NEGATION: [(Option<RustcVersion>, &str, &str); 3] = [
-    (None, "is_some", "is_none"),
-    (None, "is_err", "is_ok"),
-    (Some(msrvs::IS_NONE_OR), "is_some_and", "is_none_or"),
+const METHODS_WITH_NEGATION: [(Option<RustcVersion>, Symbol, Symbol); 3] = [
+    (None, sym::is_some, sym::is_none),
+    (None, sym::is_err, sym::is_ok),
+    (Some(msrvs::IS_NONE_OR), sym::is_some_and, sym::is_none_or),
 ];
 
 pub struct NonminimalBool {
@@ -440,9 +440,7 @@ fn simplify_not(cx: &LateContext<'_>, curr_msrv: Msrv, expr: &Expr<'_>) -> Optio
                 .iter()
                 .copied()
                 .flat_map(|(msrv, a, b)| vec![(msrv, a, b), (msrv, b, a)])
-                .find(|&(msrv, a, _)| {
-                    a == path.ident.name.as_str() && msrv.is_none_or(|msrv| curr_msrv.meets(cx, msrv))
-                })
+                .find(|&(msrv, a, _)| a == path.ident.name && msrv.is_none_or(|msrv| curr_msrv.meets(cx, msrv)))
                 .and_then(|(_, _, neg_method)| {
                     let negated_args = args
                         .iter()

diff --git a/clippy_lints/src/checked_conversions.rs b/clippy_lints/src/checked_conversions.rs
@@ -2,11 +2,12 @@ use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{SpanlessEq, is_in_const_context, is_integer_literal};
+use clippy_utils::{SpanlessEq, is_in_const_context, is_integer_literal, sym};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, QPath, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::impl_lint_pass;
+use rustc_span::Symbol;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -98,7 +99,7 @@ impl LateLintPass<'_> for CheckedConversions {
 struct Conversion<'a> {
     cvt: ConversionType,
     expr_to_cast: &'a Expr<'a>,
-    to_type: Option<&'a str>,
+    to_type: Option<Symbol>,
 }
 
 /// The kind of conversion that is checked
@@ -150,7 +151,7 @@ impl<'a> Conversion<'a> {
     }
 
     /// Try to construct a new conversion if the conversion type is valid
-    fn try_new(expr_to_cast: &'a Expr<'_>, from_type: &str, to_type: &'a str) -> Option<Conversion<'a>> {
+    fn try_new(expr_to_cast: &'a Expr<'_>, from_type: Symbol, to_type: Symbol) -> Option<Conversion<'a>> {
         ConversionType::try_new(from_type, to_type).map(|cvt| Conversion {
             cvt,
             expr_to_cast,
@@ -171,7 +172,7 @@ impl<'a> Conversion<'a> {
 impl ConversionType {
     /// Creates a conversion type if the type is allowed & conversion is valid
     #[must_use]
-    fn try_new(from: &str, to: &str) -> Option<Self> {
+    fn try_new(from: Symbol, to: Symbol) -> Option<Self> {
         if UINTS.contains(&from) {
             Some(Self::FromUnsigned)
         } else if SINTS.contains(&from) {
@@ -190,7 +191,7 @@ impl ConversionType {
 
 /// Check for `expr <= (to_type::MAX as from_type)`
 fn check_upper_bound<'tcx>(lt: &'tcx Expr<'tcx>, gt: &'tcx Expr<'tcx>) -> Option<Conversion<'tcx>> {
-    if let Some((from, to)) = get_types_from_cast(gt, INTS, "max_value", "MAX") {
+    if let Some((from, to)) = get_types_from_cast(gt, INTS, sym::max_value, sym::MAX) {
         Conversion::try_new(lt, from, to)
     } else {
         None
@@ -209,23 +210,23 @@ fn check_lower_bound_zero<'a>(candidate: &'a Expr<'_>, check: &'a Expr<'_>) -> O
 
 /// Check for `expr >= (to_type::MIN as from_type)`
 fn check_lower_bound_min<'a>(candidate: &'a Expr<'_>, check: &'a Expr<'_>) -> Option<Conversion<'a>> {
-    if let Some((from, to)) = get_types_from_cast(check, SINTS, "min_value", "MIN") {
+    if let Some((from, to)) = get_types_from_cast(check, SINTS, sym::min_value, sym::MIN) {
         Conversion::try_new(candidate, from, to)
     } else {
         None
     }
 }
 
 /// Tries to extract the from- and to-type from a cast expression
-fn get_types_from_cast<'a>(
-    expr: &'a Expr<'_>,
-    types: &'a [&str],
-    func: &'a str,
-    assoc_const: &'a str,
-) -> Option<(&'a str, &'a str)> {
+fn get_types_from_cast(
+    expr: &Expr<'_>,
+    types: &[Symbol],
+    func: Symbol,
+    assoc_const: Symbol,
+) -> Option<(Symbol, Symbol)> {
     // `to_type::max_value() as from_type`
     // or `to_type::MAX as from_type`
-    let call_from_cast: Option<(&Expr<'_>, &str)> = if let ExprKind::Cast(limit, from_type) = &expr.kind
+    let call_from_cast: Option<(&Expr<'_>, Symbol)> = if let ExprKind::Cast(limit, from_type) = &expr.kind
         // to_type::max_value(), from_type
         && let TyKind::Path(from_type_path) = &from_type.kind
         && let Some(from_sym) = int_ty_to_sym(from_type_path)
@@ -236,12 +237,12 @@ fn get_types_from_cast<'a>(
     };
 
     // `from_type::from(to_type::max_value())`
-    let limit_from: Option<(&Expr<'_>, &str)> = call_from_cast.or_else(|| {
+    let limit_from: Option<(&Expr<'_>, Symbol)> = call_from_cast.or_else(|| {
         if let ExprKind::Call(from_func, [limit]) = &expr.kind
             // `from_type::from, to_type::max_value()`
             // `from_type::from`
             && let ExprKind::Path(path) = &from_func.kind
-            && let Some(from_sym) = get_implementing_type(path, INTS, "from")
+            && let Some(from_sym) = get_implementing_type(path, INTS, sym::from)
         {
             Some((limit, from_sym))
         } else {
@@ -273,32 +274,41 @@ fn get_types_from_cast<'a>(
 }
 
 /// Gets the type which implements the called function
-fn get_implementing_type<'a>(path: &QPath<'_>, candidates: &'a [&str], function: &str) -> Option<&'a str> {
+fn get_implementing_type(path: &QPath<'_>, candidates: &[Symbol], function: Symbol) -> Option<Symbol> {
     if let QPath::TypeRelative(ty, path) = &path
-        && path.ident.name.as_str() == function
+        && path.ident.name == function
         && let TyKind::Path(QPath::Resolved(None, tp)) = &ty.kind
         && let [int] = tp.segments
     {
-        let name = int.ident.name.as_str();
-        candidates.iter().find(|c| &name == *c).copied()
+        candidates.iter().find(|c| int.ident.name == **c).copied()
     } else {
         None
     }
 }
 
 /// Gets the type as a string, if it is a supported integer
-fn int_ty_to_sym<'tcx>(path: &QPath<'_>) -> Option<&'tcx str> {
+fn int_ty_to_sym(path: &QPath<'_>) -> Option<Symbol> {
     if let QPath::Resolved(_, path) = *path
         && let [ty] = path.segments
     {
-        let name = ty.ident.name.as_str();
-        INTS.iter().find(|c| &name == *c).copied()
+        INTS.iter().find(|c| ty.ident.name == **c).copied()
     } else {
         None
     }
 }
 
 // Constants
-const UINTS: &[&str] = &["u8", "u16", "u32", "u64", "usize"];
-const SINTS: &[&str] = &["i8", "i16", "i32", "i64", "isize"];
-const INTS: &[&str] = &["u8", "u16", "u32", "u64", "usize", "i8", "i16", "i32", "i64", "isize"];
+const UINTS: &[Symbol] = &[sym::u8, sym::u16, sym::u32, sym::u64, sym::usize];
+const SINTS: &[Symbol] = &[sym::i8, sym::i16, sym::i32, sym::i64, sym::isize];
+const INTS: &[Symbol] = &[
+    sym::u8,
+    sym::u16,
+    sym::u32,
+    sym::u64,
+    sym::usize,
+    sym::i8,
+    sym::i16,
+    sym::i32,
+    sym::i64,
+    sym::isize,
+];
diff --git a/clippy_lints/src/endian_bytes.rs b/clippy_lints/src/endian_bytes.rs
@@ -1,6 +1,6 @@
 use crate::Lint;
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::is_lint_allowed;
+use clippy_utils::{is_lint_allowed, sym};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::ty::Ty;
@@ -65,9 +65,9 @@ declare_clippy_lint! {
 
 declare_lint_pass!(EndianBytes => [HOST_ENDIAN_BYTES, LITTLE_ENDIAN_BYTES, BIG_ENDIAN_BYTES]);
 
-const HOST_NAMES: [&str; 2] = ["from_ne_bytes", "to_ne_bytes"];
-const LITTLE_NAMES: [&str; 2] = ["from_le_bytes", "to_le_bytes"];
-const BIG_NAMES: [&str; 2] = ["from_be_bytes", "to_be_bytes"];
+const HOST_NAMES: [Symbol; 2] = [sym::from_ne_bytes, sym::to_ne_bytes];
+const LITTLE_NAMES: [Symbol; 2] = [sym::from_le_bytes, sym::to_le_bytes];
+const BIG_NAMES: [Symbol; 2] = [sym::from_be_bytes, sym::to_be_bytes];
 
 #[derive(Clone, Debug)]
 enum LintKind {
@@ -95,7 +95,7 @@ impl LintKind {
         }
     }
 
-    fn as_name(&self, prefix: Prefix) -> &str {
+    fn as_name(&self, prefix: Prefix) -> Symbol {
         let index = usize::from(prefix == Prefix::To);
 
         match self {
@@ -133,7 +133,7 @@ fn maybe_lint_endian_bytes(cx: &LateContext<'_>, expr: &Expr<'_>, prefix: Prefix
     let le = LintKind::Little.as_name(prefix);
     let be = LintKind::Big.as_name(prefix);
 
-    let (lint, other_lints) = match name.as_str() {
+    let (lint, other_lints) = match name {
         name if name == ne => ((&LintKind::Host), [(&LintKind::Little), (&LintKind::Big)]),
         name if name == le => ((&LintKind::Little), [(&LintKind::Host), (&LintKind::Big)]),
         name if name == be => ((&LintKind::Big), [(&LintKind::Host), (&LintKind::Little)]),

diff --git a/clippy_utils/src/sym.rs b/clippy_utils/src/sym.rs
@@ -150,8 +150,11 @@ generate! {
     floor_char_boundary,
     fold,
     for_each,
+    from_be_bytes,
     from_bytes_with_nul,
     from_bytes_with_nul_unchecked,
+    from_le_bytes,
+    from_ne_bytes,
     from_ptr,
     from_raw,
     from_ref,
@@ -184,8 +187,10 @@ generate! {
     is_err,
     is_file,
     is_none,
+    is_none_or,
     is_ok,
     is_some,
+    is_some_and,
     isqrt,
     itertools,
     join,
@@ -323,8 +328,11 @@ generate! {
     then_some,
     to_ascii_lowercase,
     to_ascii_uppercase,
+    to_be_bytes,
     to_digit,
+    to_le_bytes,
     to_lowercase,
+    to_ne_bytes,
     to_os_string,
     to_owned,
     to_path_buf,