Use symbols instead of &str when possible

Author: samueltardieu

clippy_lints/src/assertions_on_result_states.rs

@@ -3,14 +3,13 @@ use clippy_utils::macros::{PanicExpn, find_assert_args, root_macro_call_first_no
 use clippy_utils::source::snippet_with_context;
 use clippy_utils::ty::{has_debug_impl, is_copy, is_type_diagnostic_item};
 use clippy_utils::usage::local_used_after_expr;
-use clippy_utils::{is_expr_final_block_expr, path_res};
+use clippy_utils::{is_expr_final_block_expr, path_res, sym};
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, Ty};
 use rustc_session::declare_lint_pass;
-use rustc_span::sym;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -68,11 +67,11 @@ impl<'tcx> LateLintPass<'tcx> for AssertionsOnResultStates {
                     return;
                 }
             }
-            let (message, replacement) = match method_segment.ident.as_str() {
-                "is_ok" if type_suitable_to_unwrap(cx, args.type_at(1)) => {
+            let (message, replacement) = match method_segment.ident.name {
+                sym::is_ok if type_suitable_to_unwrap(cx, args.type_at(1)) => {
                     ("called `assert!` with `Result::is_ok`", "unwrap")
                 },
-                "is_err" if type_suitable_to_unwrap(cx, args.type_at(0)) => {
+                sym::is_err if type_suitable_to_unwrap(cx, args.type_at(0)) => {
                     ("called `assert!` with `Result::is_err`", "unwrap_err")
                 },
                 _ => return,

clippy_lints/src/casts/cast_possible_truncation.rs

@@ -56,15 +56,15 @@ fn apply_reductions(cx: &LateContext<'_>, nbits: u64, expr: &Expr<'_>, signed: b
             if signed {
                 return nbits;
             }
-            let max_bits = if method.ident.as_str() == "min" {
+            let max_bits = if method.ident.name == sym::min {
                 get_constant_bits(cx, right)
             } else {
                 None
             };
             apply_reductions(cx, nbits, left, signed).min(max_bits.unwrap_or(u64::MAX))
         },
         ExprKind::MethodCall(method, _, [lo, hi], _) => {
-            if method.ident.as_str() == "clamp"
+            if method.ident.name == sym::clamp
                 //FIXME: make this a diagnostic item
                 && let (Some(lo_bits), Some(hi_bits)) = (get_constant_bits(cx, lo), get_constant_bits(cx, hi))
             {

clippy_lints/src/casts/cast_sign_loss.rs

@@ -4,10 +4,11 @@ use std::ops::ControlFlow;
 use clippy_utils::consts::{ConstEvalCtxt, Constant};
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::visitors::{Descend, for_each_expr_without_closures};
-use clippy_utils::{method_chain_args, sext};
+use clippy_utils::{method_chain_args, sext, sym};
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
+use rustc_span::Symbol;
 
 use super::CAST_SIGN_LOSS;
 
@@ -16,24 +17,24 @@ use super::CAST_SIGN_LOSS;
 ///
 /// Methods that can overflow and return a negative value must not be included in this list,
 /// because casting their return values can still result in sign loss.
-const METHODS_RET_POSITIVE: &[&str] = &[
-    "checked_abs",
-    "saturating_abs",
-    "isqrt",
-    "checked_isqrt",
-    "rem_euclid",
-    "checked_rem_euclid",
-    "wrapping_rem_euclid",
+const METHODS_RET_POSITIVE: &[Symbol] = &[
+    sym::checked_abs,
+    sym::saturating_abs,
+    sym::isqrt,
+    sym::checked_isqrt,
+    sym::rem_euclid,
+    sym::checked_rem_euclid,
+    sym::wrapping_rem_euclid,
 ];
 
 /// A list of methods that act like `pow()`. See `pow_call_result_sign()` for details.
 ///
 /// Methods that can overflow and return a negative value must not be included in this list,
 /// because casting their return values can still result in sign loss.
-const METHODS_POW: &[&str] = &["pow", "saturating_pow", "checked_pow"];
+const METHODS_POW: &[Symbol] = &[sym::pow, sym::saturating_pow, sym::checked_pow];
 
 /// A list of methods that act like `unwrap()`, and don't change the sign of the inner value.
-const METHODS_UNWRAP: &[&str] = &["unwrap", "unwrap_unchecked", "expect", "into_ok"];
+const METHODS_UNWRAP: &[Symbol] = &[sym::unwrap, sym::unwrap_unchecked, sym::expect, sym::into_ok];
 
 pub(super) fn check<'cx>(
     cx: &LateContext<'cx>,
@@ -129,7 +130,7 @@ fn expr_sign<'cx, 'tcx>(cx: &LateContext<'cx>, mut expr: &'tcx Expr<'tcx>, ty: i
 
     // Calling on methods that always return non-negative values.
     if let ExprKind::MethodCall(path, caller, args, ..) = expr.kind {
-        let mut method_name = path.ident.name.as_str();
+        let mut method_name = path.ident.name;
 
         // Peel unwrap(), expect(), etc.
         while let Some(&found_name) = METHODS_UNWRAP.iter().find(|&name| &method_name == name)
@@ -138,7 +139,7 @@ fn expr_sign<'cx, 'tcx>(cx: &LateContext<'cx>, mut expr: &'tcx Expr<'tcx>, ty: i
         {
             // The original type has changed, but we can't use `ty` here anyway, because it has been
             // moved.
-            method_name = inner_path.ident.name.as_str();
+            method_name = inner_path.ident.name;
             expr = recv;
         }
 

clippy_lints/src/casts/confusing_method_to_numeric_cast.rs

@@ -1,11 +1,12 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::sym;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, GenericArg, Ty};
+use rustc_span::Symbol;
 use rustc_span::def_id::DefId;
-use rustc_span::{Symbol, sym};
 
 use super::CONFUSING_METHOD_TO_NUMERIC_CAST;
 
@@ -25,7 +26,6 @@ fn get_const_name_and_ty_name(
     method_def_id: DefId,
     generics: &[GenericArg<'_>],
 ) -> Option<(&'static str, &'static str)> {
-    let method_name = method_name.as_str();
     let diagnostic_name = cx.tcx.get_diagnostic_name(method_def_id);
 
     let ty_name = if diagnostic_name.is_some_and(|diag| diag == sym::cmp_ord_min || diag == sym::cmp_ord_max) {
@@ -39,14 +39,21 @@ fn get_const_name_and_ty_name(
         }
     } else if let Some(impl_id) = cx.tcx.impl_of_method(method_def_id)
         && let Some(ty_name) = get_primitive_ty_name(cx.tcx.type_of(impl_id).instantiate_identity())
-        && ["min", "max", "minimum", "maximum", "min_value", "max_value"].contains(&method_name)
+        && matches!(
+            method_name,
+            sym::min | sym::max | sym::minimum | sym::maximum | sym::min_value | sym::max_value
+        )
     {
         ty_name
     } else {
         return None;
     };
 
-    let const_name = if method_name.starts_with("max") { "MAX" } else { "MIN" };
+    let const_name = if matches!(method_name, sym::max | sym::maximum | sym::max_value) {
+        "MAX"
+    } else {
+        "MIN"
+    };
     Some((const_name, ty_name))
 }
 

clippy_lints/src/casts/ptr_cast_constness.rs

@@ -1,12 +1,11 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::msrvs::{self, Msrv};
-use clippy_utils::std_or_core;
 use clippy_utils::sugg::Sugg;
+use clippy_utils::{std_or_core, sym};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, Mutability, QPath};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty, TypeVisitableExt};
-use rustc_span::sym;
 
 use super::PTR_CAST_CONSTNESS;
 
@@ -78,9 +77,9 @@ pub(super) fn check_null_ptr_cast_method(cx: &LateContext<'_>, expr: &Expr<'_>)
         && let ExprKind::Call(func, []) = cast_expr.kind
         && let ExprKind::Path(QPath::Resolved(None, path)) = func.kind
         && let Some(defid) = path.res.opt_def_id()
-        && let method = match (cx.tcx.get_diagnostic_name(defid), method.ident.as_str()) {
-            (Some(sym::ptr_null), "cast_mut") => "null_mut",
-            (Some(sym::ptr_null_mut), "cast_const") => "null",
+        && let method = match (cx.tcx.get_diagnostic_name(defid), method.ident.name) {
+            (Some(sym::ptr_null), sym::cast_mut) => "null_mut",
+            (Some(sym::ptr_null_mut), sym::cast_const) => "null",
             _ => return,
         }
         && let Some(prefix) = std_or_core(cx)

clippy_lints/src/cognitive_complexity.rs

@@ -3,14 +3,14 @@ use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::source::{IntoSpan, SpanRangeExt};
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::visitors::for_each_expr_without_closures;
-use clippy_utils::{LimitStack, get_async_fn_body, is_async_fn};
+use clippy_utils::{LimitStack, get_async_fn_body, is_async_fn, sym};
 use core::ops::ControlFlow;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Attribute, Body, Expr, ExprKind, FnDecl};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::impl_lint_pass;
+use rustc_span::Span;
 use rustc_span::def_id::LocalDefId;
-use rustc_span::{Span, sym};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -157,9 +157,9 @@ impl<'tcx> LateLintPass<'tcx> for CognitiveComplexity {
     }
 
     fn check_attributes(&mut self, cx: &LateContext<'tcx>, attrs: &'tcx [Attribute]) {
-        self.limit.push_attrs(cx.sess(), attrs, "cognitive_complexity");
+        self.limit.push_attrs(cx.sess(), attrs, sym::cognitive_complexity);
     }
     fn check_attributes_post(&mut self, cx: &LateContext<'tcx>, attrs: &'tcx [Attribute]) {
-        self.limit.pop_attrs(cx.sess(), attrs, "cognitive_complexity");
+        self.limit.pop_attrs(cx.sess(), attrs, sym::cognitive_complexity);
     }
 }

clippy_lints/src/doc/missing_headers.rs

@@ -113,7 +113,8 @@ fn find_panic(cx: &LateContext<'_>, body_id: BodyId) -> Option<Span> {
         }
 
         // check for `unwrap` and `expect` for both `Option` and `Result`
-        if let Some(arglists) = method_chain_args(expr, &["unwrap"]).or_else(|| method_chain_args(expr, &["expect"]))
+        if let Some(arglists) =
+            method_chain_args(expr, &[sym::unwrap]).or_else(|| method_chain_args(expr, &[sym::expect]))
             && let receiver_ty = typeck.expr_ty(arglists[0].0).peel_refs()
             && matches!(
                 get_type_diagnostic_name(cx, receiver_ty),

clippy_lints/src/explicit_write.rs

@@ -1,13 +1,13 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::macros::{FormatArgsStorage, format_args_inputs_span};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{is_expn_of, path_def_id};
+use clippy_utils::{is_expn_of, path_def_id, sym};
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{BindingMode, Block, BlockCheckMode, Expr, ExprKind, Node, PatKind, QPath, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
-use rustc_span::{ExpnId, sym};
+use rustc_span::ExpnId;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -72,9 +72,9 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
             };
 
             // ordering is important here, since `writeln!` uses `write!` internally
-            let calling_macro = if is_expn_of(write_call.span, "writeln").is_some() {
+            let calling_macro = if is_expn_of(write_call.span, sym::writeln).is_some() {
                 Some("writeln")
-            } else if is_expn_of(write_call.span, "write").is_some() {
+            } else if is_expn_of(write_call.span, sym::write).is_some() {
                 Some("write")
             } else {
                 None

clippy_lints/src/fallible_impl_from.rs

@@ -82,7 +82,7 @@ fn lint_impl_body(cx: &LateContext<'_>, impl_span: Span, impl_items: &[hir::Impl
             }
 
             // check for `unwrap`
-            if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
+            if let Some(arglists) = method_chain_args(expr, &[sym::unwrap]) {
                 let receiver_ty = self.typeck_results.expr_ty(arglists[0].0).peel_refs();
                 if is_type_diagnostic_item(self.lcx, receiver_ty, sym::Option)
                     || is_type_diagnostic_item(self.lcx, receiver_ty, sym::Result)

clippy_lints/src/floating_point_arithmetic.rs

@@ -294,8 +294,8 @@ fn check_powi(cx: &LateContext<'_>, expr: &Expr<'_>, receiver: &Expr<'_>, args:
         && let Some(parent) = get_parent_expr(cx, expr)
     {
         if let Some(grandparent) = get_parent_expr(cx, parent)
-            && let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = grandparent.kind
-            && method_name.as_str() == "sqrt"
+            && let ExprKind::MethodCall(PathSegment { ident: method, .. }, receiver, ..) = grandparent.kind
+            && method.name == sym::sqrt
             && detect_hypot(cx, receiver).is_some()
         {
             return;
@@ -375,24 +375,10 @@ fn detect_hypot(cx: &LateContext<'_>, receiver: &Expr<'_>) -> Option<String> {
         }
 
         // check if expression of the form x.powi(2) + y.powi(2)
-        if let ExprKind::MethodCall(
-            PathSegment {
-                ident: lmethod_name, ..
-            },
-            largs_0,
-            [largs_1, ..],
-            _,
-        ) = &add_lhs.kind
-            && let ExprKind::MethodCall(
-                PathSegment {
-                    ident: rmethod_name, ..
-                },
-                rargs_0,
-                [rargs_1, ..],
-                _,
-            ) = &add_rhs.kind
-            && lmethod_name.as_str() == "powi"
-            && rmethod_name.as_str() == "powi"
+        if let ExprKind::MethodCall(PathSegment { ident: lmethod, .. }, largs_0, [largs_1, ..], _) = &add_lhs.kind
+            && let ExprKind::MethodCall(PathSegment { ident: rmethod, .. }, rargs_0, [rargs_1, ..], _) = &add_rhs.kind
+            && lmethod.name == sym::powi
+            && rmethod.name == sym::powi
             && let ecx = ConstEvalCtxt::new(cx)
             && let Some(lvalue) = ecx.eval(largs_1)
             && let Some(rvalue) = ecx.eval(rargs_1)
@@ -482,8 +468,8 @@ fn check_mul_add(cx: &LateContext<'_>, expr: &Expr<'_>) {
     ) = &expr.kind
     {
         if let Some(parent) = get_parent_expr(cx, expr)
-            && let ExprKind::MethodCall(PathSegment { ident: method_name, .. }, receiver, ..) = parent.kind
-            && method_name.as_str() == "sqrt"
+            && let ExprKind::MethodCall(PathSegment { ident: method, .. }, receiver, ..) = parent.kind
+            && method.name == sym::sqrt
             && detect_hypot(cx, receiver).is_some()
         {
             return;
@@ -623,27 +609,13 @@ fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
 }
 
 fn are_same_base_logs(cx: &LateContext<'_>, expr_a: &Expr<'_>, expr_b: &Expr<'_>) -> bool {
-    if let ExprKind::MethodCall(
-        PathSegment {
-            ident: method_name_a, ..
-        },
-        _,
-        args_a,
-        _,
-    ) = expr_a.kind
-        && let ExprKind::MethodCall(
-            PathSegment {
-                ident: method_name_b, ..
-            },
-            _,
-            args_b,
-            _,
-        ) = expr_b.kind
+    if let ExprKind::MethodCall(PathSegment { ident: method_a, .. }, _, args_a, _) = expr_a.kind
+        && let ExprKind::MethodCall(PathSegment { ident: method_b, .. }, _, args_b, _) = expr_b.kind
     {
-        return method_name_a.as_str() == method_name_b.as_str()
+        return method_a.name == method_b.name
             && args_a.len() == args_b.len()
-            && (["ln", "log2", "log10"].contains(&method_name_a.as_str())
-                || method_name_a.as_str() == "log" && args_a.len() == 1 && eq_expr_value(cx, &args_a[0], &args_b[0]));
+            && (matches!(method_a.name, sym::ln | sym::log2 | sym::log10)
+                || method_a.name == sym::log && args_a.len() == 1 && eq_expr_value(cx, &args_a[0], &args_b[0]));
     }
 
     false