Auto merge of #6284 - camsteffen:rustc-sym, r=flip1995

Use const sym where possible

I ran a regex search and replace to use const `sym` values where possible. This should give some performance boost by avoiding string interning at runtime.

Con: It is not as consistent as always using `sym!`.

I also changed an internal lint to suggest using `sym::{}`, making an assumption that this will always work for diagnostic items.

changelog: none

Author: bors

clippy_lints/src/attrs.rs

@@ -16,6 +16,7 @@ use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 use rustc_span::symbol::{Symbol, SymbolStr};
 use semver::Version;
 
@@ -286,14 +287,14 @@ impl<'tcx> LateLintPass<'tcx> for Attributes {
                     },
                     _ => {},
                 }
-                if items.is_empty() || !attr.has_name(sym!(deprecated)) {
+                if items.is_empty() || !attr.has_name(sym::deprecated) {
                     return;
                 }
                 for item in items {
                     if_chain! {
                         if let NestedMetaItem::MetaItem(mi) = &item;
                         if let MetaItemKind::NameValue(lit) = &mi.kind;
-                        if mi.has_name(sym!(since));
+                        if mi.has_name(sym::since);
                         then {
                             check_semver(cx, item.span(), lit);
                         }
@@ -309,7 +310,7 @@ impl<'tcx> LateLintPass<'tcx> for Attributes {
         }
         match item.kind {
             ItemKind::ExternCrate(..) | ItemKind::Use(..) => {
-                let skip_unused_imports = item.attrs.iter().any(|attr| attr.has_name(sym!(macro_use)));
+                let skip_unused_imports = item.attrs.iter().any(|attr| attr.has_name(sym::macro_use));
 
                 for attr in item.attrs {
                     if in_external_macro(cx.sess(), attr.span) {
@@ -326,7 +327,7 @@ impl<'tcx> LateLintPass<'tcx> for Attributes {
                                         match item.kind {
                                             ItemKind::Use(..) => {
                                                 if is_word(lint, sym!(unused_imports))
-                                                    || is_word(lint, sym!(deprecated))
+                                                    || is_word(lint, sym::deprecated)
                                                     || is_word(lint, sym!(unreachable_pub))
                                                     || is_word(lint, sym!(unused))
                                                     || extract_clippy_lint(lint)
@@ -411,8 +412,7 @@ fn check_clippy_lint_names(cx: &LateContext<'_>, ident: &str, items: &[NestedMet
     let lint_store = cx.lints();
     for lint in items {
         if let Some(lint_name) = extract_clippy_lint(lint) {
-            if let CheckLintNameResult::Tool(Err((None, _))) =
-                lint_store.check_lint_name(&lint_name, Some(sym!(clippy)))
+            if let CheckLintNameResult::Tool(Err((None, _))) = lint_store.check_lint_name(&lint_name, Some(sym::clippy))
             {
                 span_lint_and_then(
                     cx,
@@ -529,10 +529,10 @@ fn check_attrs(cx: &LateContext<'_>, span: Span, name: Symbol, attrs: &[Attribut
 
     for attr in attrs {
         if let Some(values) = attr.meta_item_list() {
-            if values.len() != 1 || !attr.has_name(sym!(inline)) {
+            if values.len() != 1 || !attr.has_name(sym::inline) {
                 continue;
             }
-            if is_word(&values[0], sym!(always)) {
+            if is_word(&values[0], sym::always) {
                 span_lint(
                     cx,
                     INLINE_ALWAYS,
@@ -623,12 +623,12 @@ fn check_empty_line_after_outer_attr(cx: &EarlyContext<'_>, item: &rustc_ast::It
 fn check_deprecated_cfg_attr(cx: &EarlyContext<'_>, attr: &Attribute) {
     if_chain! {
         // check cfg_attr
-        if attr.has_name(sym!(cfg_attr));
+        if attr.has_name(sym::cfg_attr);
         if let Some(items) = attr.meta_item_list();
         if items.len() == 2;
         // check for `rustfmt`
         if let Some(feature_item) = items[0].meta_item();
-        if feature_item.has_name(sym!(rustfmt));
+        if feature_item.has_name(sym::rustfmt);
         // check for `rustfmt_skip` and `rustfmt::skip`
         if let Some(skip_item) = &items[1].meta_item();
         if skip_item.has_name(sym!(rustfmt_skip)) ||
@@ -690,7 +690,7 @@ fn check_mismatched_target_os(cx: &EarlyContext<'_>, attr: &Attribute) {
     }
 
     if_chain! {
-        if attr.has_name(sym!(cfg));
+        if attr.has_name(sym::cfg);
         if let Some(list) = attr.meta_item_list();
         let mismatched = find_mismatched_target_os(&list);
         if !mismatched.is_empty();

clippy_lints/src/booleans.rs

@@ -11,6 +11,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::map::Map;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for boolean expressions that can be written more
@@ -253,8 +254,8 @@ fn simplify_not(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
         },
         ExprKind::MethodCall(path, _, args, _) if args.len() == 1 => {
             let type_of_receiver = cx.typeck_results().expr_ty(&args[0]);
-            if !is_type_diagnostic_item(cx, type_of_receiver, sym!(option_type))
-                && !is_type_diagnostic_item(cx, type_of_receiver, sym!(result_type))
+            if !is_type_diagnostic_item(cx, type_of_receiver, sym::option_type)
+                && !is_type_diagnostic_item(cx, type_of_receiver, sym::result_type)
             {
                 return None;
             }

clippy_lints/src/bytecount.rs

@@ -8,6 +8,7 @@ use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 use rustc_span::Symbol;
 
 declare_clippy_lint! {
@@ -68,7 +69,7 @@ impl<'tcx> LateLintPass<'tcx> for ByteCount {
                         let haystack = if let ExprKind::MethodCall(ref path, _, ref args, _) =
                                 filter_args[0].kind {
                             let p = path.ident.name;
-                            if (p == sym!(iter) || p == sym!(iter_mut)) && args.len() == 1 {
+                            if (p == sym::iter || p == sym!(iter_mut)) && args.len() == 1 {
                                 &args[0]
                             } else {
                                 &filter_args[0]

clippy_lints/src/cognitive_complexity.rs

@@ -7,7 +7,7 @@ use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::map::Map;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
-use rustc_span::BytePos;
+use rustc_span::{sym, BytePos};
 
 use crate::utils::{is_type_diagnostic_item, snippet_opt, span_lint_and_help, LimitStack};
 
@@ -61,7 +61,7 @@ impl CognitiveComplexity {
         helper.visit_expr(expr);
         let CCHelper { cc, returns } = helper;
         let ret_ty = cx.typeck_results().node_type(expr.hir_id);
-        let ret_adjust = if is_type_diagnostic_item(cx, ret_ty, sym!(result_type)) {
+        let ret_adjust = if is_type_diagnostic_item(cx, ret_ty, sym::result_type) {
             returns
         } else {
             #[allow(clippy::integer_division)]
@@ -123,7 +123,7 @@ impl<'tcx> LateLintPass<'tcx> for CognitiveComplexity {
         hir_id: HirId,
     ) {
         let def_id = cx.tcx.hir().local_def_id(hir_id);
-        if !cx.tcx.has_attr(def_id.to_def_id(), sym!(test)) {
+        if !cx.tcx.has_attr(def_id.to_def_id(), sym::test) {
             self.check(cx, kind, decl, body, span);
         }
     }

clippy_lints/src/doc.rs

@@ -15,7 +15,7 @@ use rustc_parse::maybe_new_parser_from_source_str;
 use rustc_session::parse::ParseSess;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::{BytePos, FilePathMapping, MultiSpan, SourceMap, Span};
-use rustc_span::{FileName, Pos};
+use rustc_span::{sym, FileName, Pos};
 use std::io;
 use std::ops::Range;
 use url::Url;
@@ -237,7 +237,7 @@ fn lint_for_missing_headers<'tcx>(
         );
     }
     if !headers.errors {
-        if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type)) {
+        if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::result_type) {
             span_lint(
                 cx,
                 MISSING_ERRORS_DOC,
@@ -255,7 +255,7 @@ fn lint_for_missing_headers<'tcx>(
                 if let ty::Opaque(_, subs) = ret_ty.kind();
                 if let Some(gen) = subs.types().next();
                 if let ty::Generator(_, subs, _) = gen.kind();
-                if is_type_diagnostic_item(cx, subs.as_generator().return_ty(), sym!(result_type));
+                if is_type_diagnostic_item(cx, subs.as_generator().return_ty(), sym::result_type);
                 then {
                     span_lint(
                         cx,
@@ -333,7 +333,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
             let (comment, current_spans) = strip_doc_comment_decoration(&comment.as_str(), comment_kind, attr.span);
             spans.extend_from_slice(&current_spans);
             doc.push_str(&comment);
-        } else if attr.has_name(sym!(doc)) {
+        } else if attr.has_name(sym::doc) {
             // ignore mix of sugared and non-sugared doc
             // don't trigger the safety or errors check
             return DocHeaders {
@@ -479,7 +479,7 @@ fn check_code(cx: &LateContext<'_>, text: &str, span: Span) {
                     | ItemKind::ExternCrate(..)
                     | ItemKind::ForeignMod(..) => return false,
                     // We found a main function ...
-                    ItemKind::Fn(_, sig, _, Some(block)) if item.ident.name == sym!(main) => {
+                    ItemKind::Fn(_, sig, _, Some(block)) if item.ident.name == sym::main => {
                         let is_async = matches!(sig.header.asyncness, Async::Yes{..});
                         let returns_nothing = match &sig.decl.output {
                             FnRetTy::Default(..) => true,

clippy_lints/src/explicit_write.rs

@@ -5,6 +5,7 @@ use rustc_errors::Applicability;
 use rustc_hir::{BorrowKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `write!()` / `writeln()!` which can be
@@ -33,7 +34,7 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
         if_chain! {
             // match call to unwrap
             if let ExprKind::MethodCall(ref unwrap_fun, _, ref unwrap_args, _) = expr.kind;
-            if unwrap_fun.ident.name == sym!(unwrap);
+            if unwrap_fun.ident.name == sym::unwrap;
             // match call to write_fmt
             if !unwrap_args.is_empty();
             if let ExprKind::MethodCall(ref write_fun, _, write_args, _) =

clippy_lints/src/fallible_impl_from.rs

@@ -6,7 +6,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::map::Map;
 use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::Span;
+use rustc_span::{sym, Span};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
@@ -95,8 +95,8 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_items: &[h
             // check for `unwrap`
             if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
                 let reciever_ty = self.typeck_results.expr_ty(&arglists[0][0]).peel_refs();
-                if is_type_diagnostic_item(self.lcx, reciever_ty, sym!(option_type))
-                    || is_type_diagnostic_item(self.lcx, reciever_ty, sym!(result_type))
+                if is_type_diagnostic_item(self.lcx, reciever_ty, sym::option_type)
+                    || is_type_diagnostic_item(self.lcx, reciever_ty, sym::result_type)
                 {
                     self.result.push(expr.span);
                 }
@@ -113,7 +113,7 @@ fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, impl_items: &[h
 
     for impl_item in impl_items {
         if_chain! {
-            if impl_item.ident.name == sym!(from);
+            if impl_item.ident.name == sym::from;
             if let ImplItemKind::Fn(_, body_id) =
                 cx.tcx.hir().impl_item(impl_item.id).kind;
             then {

clippy_lints/src/format.rs

@@ -10,6 +10,7 @@ use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, MatchSource, PatKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for the use of `format!("string literal with no
@@ -91,7 +92,7 @@ fn on_argumentv1_new<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arms: &
         if pats.len() == 1;
         then {
             let ty = cx.typeck_results().pat_ty(&pats[0]).peel_refs();
-            if *ty.kind() != rustc_middle::ty::Str && !is_type_diagnostic_item(cx, ty, sym!(string_type)) {
+            if *ty.kind() != rustc_middle::ty::Str && !is_type_diagnostic_item(cx, ty, sym::string_type) {
                 return None;
             }
             if let ExprKind::Lit(ref lit) = format_args.kind {
@@ -186,15 +187,15 @@ fn check_unformatted(expr: &Expr<'_>) -> bool {
         if exprs.len() == 1;
         // struct `core::fmt::rt::v1::Argument`
         if let ExprKind::Struct(_, ref fields, _) = exprs[0].kind;
-        if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym!(format));
+        if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
         // struct `core::fmt::rt::v1::FormatSpec`
         if let ExprKind::Struct(_, ref fields, _) = format_field.expr.kind;
-        if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym!(precision));
+        if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym::precision);
         if let ExprKind::Path(ref precision_path) = precision_field.expr.kind;
-        if last_path_segment(precision_path).ident.name == sym!(Implied);
-        if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym!(width));
+        if last_path_segment(precision_path).ident.name == sym::Implied;
+        if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym::width);
         if let ExprKind::Path(ref width_qpath) = width_field.expr.kind;
-        if last_path_segment(width_qpath).ident.name == sym!(Implied);
+        if last_path_segment(width_qpath).ident.name == sym::Implied;
         then {
             return true;
         }

clippy_lints/src/functions.rs

@@ -16,6 +16,7 @@ use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
+use rustc_span::sym;
 use rustc_target::spec::abi::Abi;
 use rustc_typeck::hir_ty_to_ty;
 
@@ -473,7 +474,7 @@ fn check_result_unit_err(cx: &LateContext<'_>, decl: &hir::FnDecl<'_>, item_span
         if !in_external_macro(cx.sess(), item_span);
         if let hir::FnRetTy::Return(ref ty) = decl.output;
         if let hir::TyKind::Path(ref qpath) = ty.kind;
-        if is_type_diagnostic_item(cx, hir_ty_to_ty(cx.tcx, ty), sym!(result_type));
+        if is_type_diagnostic_item(cx, hir_ty_to_ty(cx.tcx, ty), sym::result_type);
         if let Some(ref args) = last_path_segment(qpath).args;
         if let [_, hir::GenericArg::Type(ref err_ty)] = args.args;
         if let hir::TyKind::Tup(t) = err_ty.kind;

clippy_lints/src/get_last_with_len.rs

@@ -8,6 +8,7 @@ use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Spanned;
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for using `x.get(x.len() - 1)` instead of
@@ -55,7 +56,7 @@ impl<'tcx> LateLintPass<'tcx> for GetLastWithLen {
             // Argument 0 (the struct we're calling the method on) is a vector
             if let Some(struct_calling_on) = args.get(0);
             let struct_ty = cx.typeck_results().expr_ty(struct_calling_on);
-            if is_type_diagnostic_item(cx, struct_ty, sym!(vec_type));
+            if is_type_diagnostic_item(cx, struct_ty, sym::vec_type);
 
             // Argument to "get" is a subtraction
             if let Some(get_index_arg) = args.get(1);