diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
index 8a41aec0819..1cc5ddfd8ee 100644
--- a/compiler/rustc_ast/src/util/literal.rs
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -35,12 +35,12 @@ impl LitKind {
                 LitKind::Bool(symbol == kw::True)
             }
             token::Byte => {
-                return unescape_byte(&symbol.as_str())
+                return unescape_byte(symbol.as_str())
                     .map(LitKind::Byte)
                     .map_err(|_| LitError::LexerError);
             }
             token::Char => {
-                return unescape_char(&symbol.as_str())
+                return unescape_char(symbol.as_str())
                     .map(LitKind::Char)
                     .map_err(|_| LitError::LexerError);
             }
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index ca7a64e254e..92cae4da89a 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -1278,7 +1278,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     pub(super) fn lower_abi(&mut self, abi: StrLit) -> abi::Abi {
-        abi::lookup(&abi.symbol_unescaped.as_str()).unwrap_or_else(|| {
+        abi::lookup(abi.symbol_unescaped.as_str()).unwrap_or_else(|| {
             self.error_on_invalid_abi(abi);
             abi::Abi::Rust
         })
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 1d1539152be..45a5dc2f624 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -61,7 +61,7 @@ impl<'a> PostExpansionVisitor<'a> {
     fn check_abi(&self, abi: ast::StrLit) {
         let ast::StrLit { symbol_unescaped, span, .. } = abi;
 
-        match &*symbol_unescaped.as_str() {
+        match symbol_unescaped.as_str() {
             // Stable
             "Rust" | "C" | "cdecl" | "stdcall" | "fastcall" | "aapcs" | "win64" | "sysv64"
             | "system" => {}
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 2e511447693..6c5b38bc4bb 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -204,7 +204,7 @@ pub fn literal_to_string(lit: token::Lit) -> String {
     };
 
     if let Some(suffix) = suffix {
-        out.push_str(&suffix.as_str())
+        out.push_str(suffix.as_str())
     }
 
     out
@@ -384,7 +384,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     }
 
     fn print_symbol(&mut self, sym: Symbol, style: ast::StrStyle) {
-        self.print_string(&sym.as_str(), style);
+        self.print_string(sym.as_str(), style);
     }
 
     fn print_inner_attributes(&mut self, attrs: &[ast::Attribute]) {
diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index f441c105f70..bab50df3dd5 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -236,7 +236,7 @@ where
 
                                     // These unwraps are safe because `get` ensures the meta item
                                     // is a name/value pair string literal.
-                                    issue_num = match &*issue.unwrap().as_str() {
+                                    issue_num = match issue.unwrap().as_str() {
                                         "none" => None,
                                         issue => {
                                             let emit_diag = |msg: &str| {
@@ -301,7 +301,7 @@ where
 
                     match (feature, reason, issue) {
                         (Some(feature), reason, Some(_)) => {
-                            if !rustc_lexer::is_ident(&feature.as_str()) {
+                            if !rustc_lexer::is_ident(feature.as_str()) {
                                 handle_errors(
                                     &sess.parse_sess,
                                     attr.span,
@@ -535,7 +535,7 @@ pub fn eval_condition(
                     return false;
                 }
             };
-            let min_version = match parse_version(&min_version.as_str(), false) {
+            let min_version = match parse_version(min_version.as_str(), false) {
                 Some(ver) => ver,
                 None => {
                     sess.span_diagnostic
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 98c619cdd29..8a2d8c8432c 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -416,7 +416,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             tcx,
                             generics,
                             &mut err,
-                            &param.name.as_str(),
+                            param.name.as_str(),
                             "Copy",
                             None,
                         );
diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index dec1940ace8..2e646f55b8a 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -206,7 +206,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             {
                 let local_info = &self.body.local_decls[local].local_info;
                 if let Some(box LocalInfo::StaticRef { def_id, .. }) = *local_info {
-                    buf.push_str(&self.infcx.tcx.item_name(def_id).as_str());
+                    buf.push_str(self.infcx.tcx.item_name(def_id).as_str());
                 } else {
                     unreachable!();
                 }
@@ -318,7 +318,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let decl = &self.body.local_decls[local];
         match self.local_names[local] {
             Some(name) if !decl.from_compiler_desugaring() => {
-                buf.push_str(&name.as_str());
+                buf.push_str(name.as_str());
                 Ok(())
             }
             _ => Err(()),
diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs
index 9ae1584fcbf..42dd8095dda 100644
--- a/compiler/rustc_builtin_macros/src/asm.rs
+++ b/compiler/rustc_builtin_macros/src/asm.rs
@@ -572,7 +572,7 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::Inl
             template_snippet.as_ref().map(|s| Symbol::intern(s)),
             template_sp,
         ));
-        let template_str = &template_str.as_str();
+        let template_str = template_str.as_str();
 
         if let Some(InlineAsmArch::X86 | InlineAsmArch::X86_64) = ecx.sess.asm_arch {
             let find_span = |needle: &str| -> Span {
diff --git a/compiler/rustc_builtin_macros/src/concat.rs b/compiler/rustc_builtin_macros/src/concat.rs
index e5077d93674..59361510a67 100644
--- a/compiler/rustc_builtin_macros/src/concat.rs
+++ b/compiler/rustc_builtin_macros/src/concat.rs
@@ -21,7 +21,7 @@ pub fn expand_concat(
         match e.kind {
             ast::ExprKind::Lit(ref lit) => match lit.kind {
                 ast::LitKind::Str(ref s, _) | ast::LitKind::Float(ref s, _) => {
-                    accumulator.push_str(&s.as_str());
+                    accumulator.push_str(s.as_str());
                 }
                 ast::LitKind::Char(c) => {
                     accumulator.push(c);
diff --git a/compiler/rustc_builtin_macros/src/concat_idents.rs b/compiler/rustc_builtin_macros/src/concat_idents.rs
index 53a456b69ac..239bafb266a 100644
--- a/compiler/rustc_builtin_macros/src/concat_idents.rs
+++ b/compiler/rustc_builtin_macros/src/concat_idents.rs
@@ -29,7 +29,7 @@ pub fn expand_concat_idents<'cx>(
         } else {
             if let TokenTree::Token(token) = e {
                 if let Some((ident, _)) = token.ident() {
-                    res_str.push_str(&ident.name.as_str());
+                    res_str.push_str(ident.name.as_str());
                     continue;
                 }
             }
diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index 31a35b9b7b4..47d7b6c259e 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -121,7 +121,7 @@ fn report_bad_target(sess: &Session, item: &Annotatable, span: Span) -> bool {
 
 fn report_unexpected_literal(sess: &Session, lit: &ast::Lit) {
     let help_msg = match lit.token.kind {
-        token::Str if rustc_lexer::is_ident(&lit.token.symbol.as_str()) => {
+        token::Str if rustc_lexer::is_ident(lit.token.symbol.as_str()) => {
             format!("try using `#[derive({})]`", lit.token.symbol)
         }
         _ => "for example, write `#[derive(Debug)]` for `Debug`".to_string(),
diff --git a/compiler/rustc_builtin_macros/src/env.rs b/compiler/rustc_builtin_macros/src/env.rs
index 6de12acfb94..285027fc632 100644
--- a/compiler/rustc_builtin_macros/src/env.rs
+++ b/compiler/rustc_builtin_macros/src/env.rs
@@ -80,11 +80,11 @@ pub fn expand_env<'cx>(
     }
 
     let sp = cx.with_def_site_ctxt(sp);
-    let value = env::var(&*var.as_str()).ok().as_deref().map(Symbol::intern);
+    let value = env::var(var.as_str()).ok().as_deref().map(Symbol::intern);
     cx.sess.parse_sess.env_depinfo.borrow_mut().insert((var, value));
     let e = match value {
         None => {
-            cx.span_err(sp, &msg.as_str());
+            cx.span_err(sp, msg.as_str());
             return DummyResult::any(sp);
         }
         Some(value) => cx.expr_str(sp, value),
diff --git a/compiler/rustc_builtin_macros/src/format.rs b/compiler/rustc_builtin_macros/src/format.rs
index cd16172fa31..407aaacb889 100644
--- a/compiler/rustc_builtin_macros/src/format.rs
+++ b/compiler/rustc_builtin_macros/src/format.rs
@@ -955,7 +955,7 @@ pub fn expand_preparsed_format_args(
         ast::StrStyle::Raw(raw) => Some(raw as usize),
     };
 
-    let fmt_str = &fmt_str.as_str(); // for the suggestions below
+    let fmt_str = fmt_str.as_str(); // for the suggestions below
     let fmt_snippet = ecx.source_map().span_to_snippet(fmt_sp).ok();
     let mut parser = parse::Parser::new(
         fmt_str,
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index 0a8d6122aa7..c09be5f7597 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -84,7 +84,7 @@ fn reuse_workproduct_for_cgu(
     let work_product = cgu.work_product(tcx);
     if let Some(saved_file) = &work_product.saved_file {
         let obj_out =
-            tcx.output_filenames(()).temp_path(OutputType::Object, Some(&cgu.name().as_str()));
+            tcx.output_filenames(()).temp_path(OutputType::Object, Some(cgu.name().as_str()));
         object = Some(obj_out.clone());
         let source_file = rustc_incremental::in_incr_comp_dir_sess(&tcx.sess, &saved_file);
         if let Err(err) = rustc_fs_util::link_or_copy(&source_file, &obj_out) {
@@ -176,7 +176,7 @@ fn module_codegen(
         )
     });
 
-    codegen_global_asm(tcx, &cgu.name().as_str(), &cx.global_asm);
+    codegen_global_asm(tcx, cgu.name().as_str(), &cx.global_asm);
 
     codegen_result
 }
@@ -207,7 +207,7 @@ pub(crate) fn run_aot(
         cgus.iter()
             .map(|cgu| {
                 let cgu_reuse = determine_cgu_reuse(tcx, cgu);
-                tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
+                tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
 
                 match cgu_reuse {
                     _ if backend_config.disable_incr_cache => {}
diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs
index bda08b653f0..ec542e55681 100644
--- a/compiler/rustc_codegen_gcc/src/common.rs
+++ b/compiler/rustc_codegen_gcc/src/common.rs
@@ -33,7 +33,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
             return value;
         }
 
-        let global = self.global_string(&*symbol.as_str());
+        let global = self.global_string(symbol.as_str());
 
         self.const_cstr_cache.borrow_mut().insert(symbol, global);
         global
diff --git a/compiler/rustc_codegen_gcc/src/declare.rs b/compiler/rustc_codegen_gcc/src/declare.rs
index b79a50d1eee..dbee505a497 100644
--- a/compiler/rustc_codegen_gcc/src/declare.rs
+++ b/compiler/rustc_codegen_gcc/src/declare.rs
@@ -17,7 +17,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
                 global.set_tls_model(self.tls_model);
             }
             if let Some(link_section) = link_section {
-                global.set_link_section(&link_section.as_str());
+                global.set_link_section(link_section.as_str());
             }
             global
         }
@@ -53,7 +53,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
             global.set_tls_model(self.tls_model);
         }
         if let Some(link_section) = link_section {
-            global.set_link_section(&link_section.as_str());
+            global.set_link_section(link_section.as_str());
         }
         let global_address = global.get_address(None);
         self.globals.borrow_mut().insert(name.to_string(), global_address);
diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs b/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
index f3a2382ef32..0782adeb6a1 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/mod.rs
@@ -88,7 +88,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
         let arg_tys = sig.inputs();
         let ret_ty = sig.output();
         let name = tcx.item_name(def_id);
-        let name_str = &*name.as_str();
+        let name_str = name.as_str();
 
         let llret_ty = self.layout_of(ret_ty).gcc_type(self, true);
         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
index 26a42217e4c..aff27f71d91 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
@@ -52,7 +52,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(bx: &mut Builder<'a, 'gcc, 'tcx>,
     let sig =
         tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), callee_ty.fn_sig(tcx));
     let arg_tys = sig.inputs();
-    let name_str = &*name.as_str();
+    let name_str = name.as_str();
 
     // every intrinsic below takes a SIMD vector as its first argument
     require_simd!(arg_tys[0], "input");
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs
index 8e6329a997f..f8ffcd94734 100644
--- a/compiler/rustc_codegen_llvm/src/attributes.rs
+++ b/compiler/rustc_codegen_llvm/src/attributes.rs
@@ -322,7 +322,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
         .target_features
         .iter()
         .flat_map(|f| {
-            let feature = &f.as_str();
+            let feature = f.as_str();
             llvm_util::to_llvm_feature(cx.tcx.sess, feature)
                 .into_iter()
                 .map(|f| format!("+{}", f))
@@ -347,7 +347,7 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
 
             let name =
                 codegen_fn_attrs.link_name.unwrap_or_else(|| cx.tcx.item_name(instance.def_id()));
-            let name = CString::new(&name.as_str()[..]).unwrap();
+            let name = CString::new(name.as_str()).unwrap();
             llvm::AddFunctionAttrStringValue(
                 llfn,
                 llvm::AttributePlace::Function,
diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
index 7a3e11e32bc..a539b0e3f16 100644
--- a/compiler/rustc_codegen_llvm/src/base.rs
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -82,7 +82,7 @@ pub fn compile_codegen_unit(
             &[cgu_name.to_string(), cgu.size_estimate().to_string()],
         );
         // Instantiate monomorphizations without filling out definitions yet...
-        let llvm_module = ModuleLlvm::new(tcx, &cgu_name.as_str());
+        let llvm_module = ModuleLlvm::new(tcx, cgu_name.as_str());
         {
             let cx = CodegenCx::new(tcx, cgu, &llvm_module);
             let mono_items = cx.codegen_unit.items_in_deterministic_order(cx.tcx);
@@ -146,7 +146,7 @@ pub fn set_link_section(llval: &Value, attrs: &CodegenFnAttrs) {
         None => return,
     };
     unsafe {
-        let buf = SmallCStr::new(&sect.as_str());
+        let buf = SmallCStr::new(sect.as_str());
         llvm::LLVMSetSection(llval, buf.as_ptr());
     }
 }
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 613a8df891c..2b94d5f6780 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -320,7 +320,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
 
         let dbg_cx = if tcx.sess.opts.debuginfo != DebugInfo::None {
             let dctx = debuginfo::CrateDebugContext::new(llmod);
-            debuginfo::metadata::compile_unit_metadata(tcx, &codegen_unit.name().as_str(), &dctx);
+            debuginfo::metadata::compile_unit_metadata(tcx, codegen_unit.name().as_str(), &dctx);
             Some(dctx)
         } else {
             None
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 7fdde653833..37825cc3fc7 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -1033,7 +1033,7 @@ pub fn compile_unit_metadata(
 ) -> &'ll DIDescriptor {
     let mut name_in_debuginfo = match tcx.sess.local_crate_source_file {
         Some(ref path) => path.clone(),
-        None => PathBuf::from(&*tcx.crate_name(LOCAL_CRATE).as_str()),
+        None => PathBuf::from(tcx.crate_name(LOCAL_CRATE).as_str()),
     };
 
     // The OSX linker has an idiosyncrasy where it will ignore some debuginfo
@@ -1353,7 +1353,7 @@ fn closure_saved_names_of_captured_variables(tcx: TyCtxt<'tcx>, def_id: DefId) -
                 _ => return None,
             };
             let prefix = if is_ref { "_ref__" } else { "" };
-            Some(prefix.to_owned() + &var.name.as_str())
+            Some(prefix.to_owned() + var.name.as_str())
         })
         .collect::<Vec<_>>()
 }
@@ -2421,7 +2421,7 @@ fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> &'ll DIAr
                             cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty);
                         let actual_type_metadata =
                             type_metadata(cx, actual_type, rustc_span::DUMMY_SP);
-                        let name = &name.as_str();
+                        let name = name.as_str();
                         Some(unsafe {
                             Some(llvm::LLVMRustDIBuilderCreateTemplateTypeParameter(
                                 DIB(cx),
diff --git a/compiler/rustc_codegen_ssa/src/back/command.rs b/compiler/rustc_codegen_ssa/src/back/command.rs
index 503c51d24b6..17071ba1b5b 100644
--- a/compiler/rustc_codegen_ssa/src/back/command.rs
+++ b/compiler/rustc_codegen_ssa/src/back/command.rs
@@ -48,7 +48,7 @@ impl Command {
     }
 
     pub fn sym_arg(&mut self, arg: Symbol) -> &mut Command {
-        self.arg(&*arg.as_str());
+        self.arg(arg.as_str());
         self
     }
 
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index bf45810de77..d4e855ac932 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -88,7 +88,7 @@ pub fn link_binary<'a, B: ArchiveBuilder<'a>>(
                 sess,
                 crate_type,
                 outputs,
-                &codegen_results.crate_info.local_crate_name.as_str(),
+                codegen_results.crate_info.local_crate_name.as_str(),
             );
             match crate_type {
                 CrateType::Rlib => {
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index d82aa691545..fac8f3dccc4 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -672,7 +672,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         }
 
         let cgu_reuse = cgu_reuse[i];
-        tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
+        tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
 
         match cgu_reuse {
             CguReuse::No => {
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
index ab119ae25f5..d340cce8495 100644
--- a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
+++ b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -516,7 +516,7 @@ fn push_unqualified_item_name(
 ) {
     match disambiguated_data.data {
         DefPathData::CrateRoot => {
-            output.push_str(&tcx.crate_name(def_id.krate).as_str());
+            output.push_str(tcx.crate_name(def_id.krate).as_str());
         }
         DefPathData::ClosureExpr if tcx.generator_kind(def_id).is_some() => {
             // Generators look like closures, but we want to treat them differently
@@ -529,7 +529,7 @@ fn push_unqualified_item_name(
         }
         _ => match disambiguated_data.data.name() {
             DefPathDataName::Named(name) => {
-                output.push_str(&name.as_str());
+                output.push_str(name.as_str());
             }
             DefPathDataName::Anon { namespace } => {
                 if cpp_like_names(tcx) {
diff --git a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
index f943157dc66..3657f80c2de 100644
--- a/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/intrinsic.rs
@@ -68,7 +68,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let arg_tys = sig.inputs();
         let ret_ty = sig.output();
         let name = bx.tcx().item_name(def_id);
-        let name_str = &*name.as_str();
+        let name_str = name.as_str();
 
         let llret_ty = bx.backend_type(bx.layout_of(ret_ty));
         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
@@ -375,7 +375,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 use crate::common::AtomicOrdering::*;
                 use crate::common::{AtomicRmwBinOp, SynchronizationScope};
 
-                let split: Vec<&str> = name_str.split('_').collect();
+                let split: Vec<_> = name_str.split('_').collect();
 
                 let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
                 let (order, failorder) = match split.len() {
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
index b5e97ec8fe0..058903dcdee 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
@@ -82,7 +82,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> MPlaceTy<'tcx, M::PointerTag> {
         let loc_details = &self.tcx.sess.opts.debugging_opts.location_detail;
         let file = if loc_details.file {
-            self.allocate_str(&filename.as_str(), MemoryKind::CallerLocation, Mutability::Not)
+            self.allocate_str(filename.as_str(), MemoryKind::CallerLocation, Mutability::Not)
         } else {
             // FIXME: This creates a new allocation each time. It might be preferable to
             // perform this allocation only once, and re-use the `MPlaceTy`.
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
index 5b4a5ac3577..d166bc78f51 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs
@@ -88,7 +88,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
     }
 
     fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
-        self.path.push_str(&self.tcx.crate_name(cnum).as_str());
+        self.path.push_str(self.tcx.crate_name(cnum).as_str());
         Ok(self)
     }
 
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index 5221ab4b613..db0dea48708 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -171,7 +171,7 @@ fn get_features(
             }
 
             if let Some(allowed) = sess.opts.debugging_opts.allow_features.as_ref() {
-                if allowed.iter().all(|f| name.as_str() != *f) {
+                if allowed.iter().all(|f| name.as_str() != f) {
                     struct_span_err!(
                         span_handler,
                         mi.span(),
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index b7e47e4da6f..56564656556 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -331,9 +331,9 @@ pub struct Ident {
 
 impl Ident {
     fn new(sess: &ParseSess, sym: Symbol, is_raw: bool, span: Span) -> Ident {
-        let sym = nfc_normalize(&sym.as_str());
+        let sym = nfc_normalize(sym.as_str());
         let string = sym.as_str();
-        if !rustc_lexer::is_ident(&string) {
+        if !rustc_lexer::is_ident(string) {
             panic!("`{:?}` is not a valid identifier", string)
         }
         if is_raw && !sym.can_be_raw() {
diff --git a/compiler/rustc_hir/src/definitions.rs b/compiler/rustc_hir/src/definitions.rs
index ca29351455e..37325766935 100644
--- a/compiler/rustc_hir/src/definitions.rs
+++ b/compiler/rustc_hir/src/definitions.rs
@@ -173,7 +173,7 @@ impl DisambiguatedDefPathData {
                 if verbose && self.disambiguator != 0 {
                     write!(writer, "{}#{}", name, self.disambiguator)
                 } else {
-                    writer.write_str(&name.as_str())
+                    writer.write_str(name.as_str())
                 }
             }
             DefPathDataName::Anon { namespace } => {
@@ -494,7 +494,7 @@ impl DefPathData {
 impl fmt::Display for DefPathData {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.name() {
-            DefPathDataName::Named(name) => f.write_str(&name.as_str()),
+            DefPathDataName::Named(name) => f.write_str(name.as_str()),
             // FIXME(#70334): this will generate legacy {{closure}}, {{impl}}, etc
             DefPathDataName::Anon { namespace } => write!(f, "{{{{{}}}}}", namespace),
         }
diff --git a/compiler/rustc_incremental/src/assert_dep_graph.rs b/compiler/rustc_incremental/src/assert_dep_graph.rs
index 7b5b015d5a5..8fdd94daafe 100644
--- a/compiler/rustc_incremental/src/assert_dep_graph.rs
+++ b/compiler/rustc_incremental/src/assert_dep_graph.rs
@@ -131,7 +131,7 @@ impl IfThisChanged<'tcx> {
                         DepNode::from_def_path_hash(self.tcx, def_path_hash, DepKind::hir_owner)
                     }
                     Some(n) => {
-                        match DepNode::from_label_string(self.tcx, &n.as_str(), def_path_hash) {
+                        match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
                             Ok(n) => n,
                             Err(()) => {
                                 self.tcx.sess.span_fatal(
@@ -147,7 +147,7 @@ impl IfThisChanged<'tcx> {
                 let dep_node_interned = self.argument(attr);
                 let dep_node = match dep_node_interned {
                     Some(n) => {
-                        match DepNode::from_label_string(self.tcx, &n.as_str(), def_path_hash) {
+                        match DepNode::from_label_string(self.tcx, n.as_str(), def_path_hash) {
                             Ok(n) => n,
                             Err(()) => {
                                 self.tcx.sess.span_fatal(
diff --git a/compiler/rustc_incremental/src/assert_module_sources.rs b/compiler/rustc_incremental/src/assert_module_sources.rs
index 2cf8f9b08e1..9fc45c3d165 100644
--- a/compiler/rustc_incremental/src/assert_module_sources.rs
+++ b/compiler/rustc_incremental/src/assert_module_sources.rs
@@ -124,7 +124,7 @@ impl AssertModuleSource<'tcx> {
 
         debug!("mapping '{}' to cgu name '{}'", self.field(attr, sym::module), cgu_name);
 
-        if !self.available_cgus.contains(&*cgu_name.as_str()) {
+        if !self.available_cgus.contains(cgu_name.as_str()) {
             self.tcx.sess.span_err(
                 attr.span,
                 &format!(
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 1e3f9f7464d..2099af39dca 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -2252,8 +2252,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                             .map(|p| p.name.as_str()),
                     );
                 }
-                let lts = lts_names.iter().map(|s| -> &str { &*s }).collect::<Vec<_>>();
-                possible.find(|candidate| !lts.contains(&candidate.as_str()))
+                possible.find(|candidate| !lts_names.contains(&&candidate[..]))
             })
             .unwrap_or("'lt".to_string());
         let add_lt_sugg = generics
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index e7ae6c7687c..6268fc64778 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -324,7 +324,7 @@ pub fn configure_and_expand(
         let crate_attrs = krate.attrs.clone();
         let extern_mod_loaded = |ident: Ident, attrs, items, span| {
             let krate = ast::Crate { attrs, items, span, is_placeholder: None };
-            pre_expansion_lint(sess, lint_store, &krate, &crate_attrs, &ident.name.as_str());
+            pre_expansion_lint(sess, lint_store, &krate, &crate_attrs, ident.name.as_str());
             (krate.attrs, krate.items)
         };
         let mut ecx = ExtCtxt::new(sess, cfg, resolver, Some(&extern_mod_loaded));
@@ -631,7 +631,7 @@ fn write_out_deps(
         // (e.g. accessed in proc macros).
         let file_depinfo = sess.parse_sess.file_depinfo.borrow();
         let extra_tracked_files = file_depinfo.iter().map(|path_sym| {
-            let path = PathBuf::from(&*path_sym.as_str());
+            let path = PathBuf::from(path_sym.as_str());
             let file = FileName::from(path);
             escape_dep_filename(&file.prefer_local().to_string())
         });
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 5dbcc1655c9..d31f30a8103 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -3183,7 +3183,7 @@ impl<'tcx> LateLintPass<'tcx> for NamedAsmLabels {
         } = expr
         {
             for (template_sym, template_snippet, template_span) in template_strs.iter() {
-                let template_str = &template_sym.as_str();
+                let template_str = template_sym.as_str();
                 let find_label_span = |needle: &str| -> Option<Span> {
                     if let Some(template_snippet) = template_snippet {
                         let snippet = template_snippet.as_str();
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index 3c79020523a..0f6b7d6af96 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -381,10 +381,10 @@ impl LintStore {
             lint_name,
             self.lint_groups.keys().collect::<Vec<_>>()
         );
-        let lint_name_str = &*lint_name.as_str();
-        self.lint_groups.contains_key(&lint_name_str) || {
+        let lint_name_str = lint_name.as_str();
+        self.lint_groups.contains_key(lint_name_str) || {
             let warnings_name_str = crate::WARNINGS.name_lower();
-            lint_name_str == &*warnings_name_str
+            lint_name_str == warnings_name_str
         }
     }
 
diff --git a/compiler/rustc_lint/src/hidden_unicode_codepoints.rs b/compiler/rustc_lint/src/hidden_unicode_codepoints.rs
index fde84be9a7c..fc99d759a03 100644
--- a/compiler/rustc_lint/src/hidden_unicode_codepoints.rs
+++ b/compiler/rustc_lint/src/hidden_unicode_codepoints.rs
@@ -127,7 +127,7 @@ impl HiddenUnicodeCodepoints {
 impl EarlyLintPass for HiddenUnicodeCodepoints {
     fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
         if let ast::AttrKind::DocComment(_, comment) = attr.kind {
-            if contains_text_flow_control_chars(&comment.as_str()) {
+            if contains_text_flow_control_chars(comment.as_str()) {
                 self.lint_text_direction_codepoint(cx, comment, attr.span, 0, false, "doc comment");
             }
         }
@@ -138,7 +138,7 @@ impl EarlyLintPass for HiddenUnicodeCodepoints {
         let (text, span, padding) = match &expr.kind {
             ast::ExprKind::Lit(ast::Lit { token, kind, span }) => {
                 let text = token.symbol;
-                if !contains_text_flow_control_chars(&text.as_str()) {
+                if !contains_text_flow_control_chars(text.as_str()) {
                     return;
                 }
                 let padding = match kind {
diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs
index 485728cbfd3..d3fa08650d8 100644
--- a/compiler/rustc_lint/src/levels.rs
+++ b/compiler/rustc_lint/src/levels.rs
@@ -154,7 +154,7 @@ impl<'s> LintLevelsBuilder<'s> {
                         LintLevelSource::Node(_, forbid_source_span, reason) => {
                             diag_builder.span_label(forbid_source_span, "`forbid` level set here");
                             if let Some(rationale) = reason {
-                                diag_builder.note(&rationale.as_str());
+                                diag_builder.note(rationale.as_str());
                             }
                         }
                         LintLevelSource::CommandLine(_, _) => {
diff --git a/compiler/rustc_lint/src/non_ascii_idents.rs b/compiler/rustc_lint/src/non_ascii_idents.rs
index 9b4ee148df4..a570206f1ee 100644
--- a/compiler/rustc_lint/src/non_ascii_idents.rs
+++ b/compiler/rustc_lint/src/non_ascii_idents.rs
@@ -218,8 +218,7 @@ impl EarlyLintPass for NonAsciiIdents {
                             cx.struct_span_lint(CONFUSABLE_IDENTS, sp, |lint| {
                                 lint.build(&format!(
                                     "identifier pair considered confusable between `{}` and `{}`",
-                                    existing_symbol.as_str(),
-                                    symbol.as_str()
+                                    existing_symbol, symbol
                                 ))
                                 .span_label(
                                     *existing_span,
diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index b63167f56b8..a919b3c82aa 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -71,7 +71,7 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
     if let hir::ExprKind::Lit(lit) = &arg.kind {
         if let ast::LitKind::Str(sym, _) = lit.node {
             // The argument is a string literal.
-            check_panic_str(cx, f, arg, &sym.as_str());
+            check_panic_str(cx, f, arg, sym.as_str());
             return;
         }
     }
diff --git a/compiler/rustc_lint/src/nonstandard_style.rs b/compiler/rustc_lint/src/nonstandard_style.rs
index bcddc4f3d76..be7756b0f28 100644
--- a/compiler/rustc_lint/src/nonstandard_style.rs
+++ b/compiler/rustc_lint/src/nonstandard_style.rs
@@ -133,7 +133,7 @@ fn to_camel_case(s: &str) -> String {
 
 impl NonCamelCaseTypes {
     fn check_case(&self, cx: &EarlyContext<'_>, sort: &str, ident: &Ident) {
-        let name = &ident.name.as_str();
+        let name = ident.name.as_str();
 
         if !is_camel_case(name) {
             cx.struct_span_lint(NON_CAMEL_CASE_TYPES, ident.span, |lint| {
@@ -276,7 +276,7 @@ impl NonSnakeCase {
             })
         }
 
-        let name = &ident.name.as_str();
+        let name = ident.name.as_str();
 
         if !is_snake_case(name) {
             cx.struct_span_lint(NON_SNAKE_CASE, ident.span, |lint| {
@@ -484,7 +484,7 @@ declare_lint_pass!(NonUpperCaseGlobals => [NON_UPPER_CASE_GLOBALS]);
 
 impl NonUpperCaseGlobals {
     fn check_upper_case(cx: &LateContext<'_>, sort: &str, ident: &Ident) {
-        let name = &ident.name.as_str();
+        let name = ident.name.as_str();
         if name.chars().any(|c| c.is_lowercase()) {
             cx.struct_span_lint(NON_UPPER_CASE_GLOBALS, ident.span, |lint| {
                 let uc = NonSnakeCase::to_snake_case(&name).to_uppercase();
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index da1edcf6fe3..08fa108627f 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -313,7 +313,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                         let mut err = lint.build(&msg);
                         // check for #[must_use = "..."]
                         if let Some(note) = attr.value_str() {
-                            err.note(&note.as_str());
+                            err.note(note.as_str());
                         }
                         err.emit();
                     });
diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index e304682a2d4..c0da386edfd 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -292,7 +292,7 @@ impl<'a> CrateLoader<'a> {
             // `source` stores paths which are normalized which may be different
             // from the strings on the command line.
             let source = self.cstore.get_crate_data(cnum).cdata.source();
-            if let Some(entry) = self.sess.opts.externs.get(&name.as_str()) {
+            if let Some(entry) = self.sess.opts.externs.get(name.as_str()) {
                 // Only use `--extern crate_name=path` here, not `--extern crate_name`.
                 if let Some(mut files) = entry.files() {
                     if files.any(|l| {
@@ -381,7 +381,7 @@ impl<'a> CrateLoader<'a> {
         let host_hash = host_lib.as_ref().map(|lib| lib.metadata.get_root().hash());
 
         let private_dep =
-            self.sess.opts.externs.get(&name.as_str()).map_or(false, |e| e.is_private_dep);
+            self.sess.opts.externs.get(name.as_str()).map_or(false, |e| e.is_private_dep);
 
         // Claim this crate number and cache it
         let cnum = self.cstore.alloc_new_crate_num();
@@ -997,7 +997,7 @@ impl<'a> CrateLoader<'a> {
                 );
                 let name = match orig_name {
                     Some(orig_name) => {
-                        validate_crate_name(self.sess, &orig_name.as_str(), Some(item.span));
+                        validate_crate_name(self.sess, orig_name.as_str(), Some(item.span));
                         orig_name
                     }
                     None => item.ident.name,
diff --git a/compiler/rustc_metadata/src/locator.rs b/compiler/rustc_metadata/src/locator.rs
index 99927a08935..7f14404ebea 100644
--- a/compiler/rustc_metadata/src/locator.rs
+++ b/compiler/rustc_metadata/src/locator.rs
@@ -315,7 +315,7 @@ impl<'a> CrateLocator<'a> {
             exact_paths: if hash.is_none() {
                 sess.opts
                     .externs
-                    .get(&crate_name.as_str())
+                    .get(crate_name.as_str())
                     .into_iter()
                     .filter_map(|entry| entry.files())
                     .flatten()
@@ -1175,7 +1175,7 @@ impl CrateError {
                     } else if crate_name
                         == Symbol::intern(&sess.opts.debugging_opts.profiler_runtime)
                     {
-                        err.note(&"the compiler may have been built without the profiler runtime");
+                        err.note("the compiler may have been built without the profiler runtime");
                     } else if crate_name.as_str().starts_with("rustc_") {
                         err.help(
                             "maybe you need to install the missing components with: \
diff --git a/compiler/rustc_metadata/src/native_libs.rs b/compiler/rustc_metadata/src/native_libs.rs
index 9adf9406f09..889145d3f98 100644
--- a/compiler/rustc_metadata/src/native_libs.rs
+++ b/compiler/rustc_metadata/src/native_libs.rs
@@ -67,7 +67,7 @@ impl ItemLikeVisitor<'tcx> for Collector<'tcx> {
                         Some(name) => name,
                         None => continue, // skip like historical compilers
                     };
-                    lib.kind = match &*kind.as_str() {
+                    lib.kind = match kind.as_str() {
                         "static" => NativeLibKind::Static { bundle: None, whole_archive: None },
                         "static-nobundle" => {
                             sess.struct_span_warn(
diff --git a/compiler/rustc_middle/src/lint.rs b/compiler/rustc_middle/src/lint.rs
index 881b14278e9..22e791bb14c 100644
--- a/compiler/rustc_middle/src/lint.rs
+++ b/compiler/rustc_middle/src/lint.rs
@@ -319,7 +319,7 @@ pub fn struct_lint_level<'s, 'd>(
             }
             LintLevelSource::Node(lint_attr_name, src, reason) => {
                 if let Some(rationale) = reason {
-                    err.note(&rationale.as_str());
+                    err.note(rationale.as_str());
                 }
                 sess.diag_span_note_once(
                     &mut err,
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index afd8083dfe4..96df0525ade 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -2473,7 +2473,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                             if let Some(upvars) = tcx.upvars_mentioned(def_id) {
                                 for (&var_id, place) in iter::zip(upvars.keys(), places) {
                                     let var_name = tcx.hir().name(var_id);
-                                    struct_fmt.field(&var_name.as_str(), place);
+                                    struct_fmt.field(var_name.as_str(), place);
                                 }
                             }
 
@@ -2493,7 +2493,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                             if let Some(upvars) = tcx.upvars_mentioned(def_id) {
                                 for (&var_id, place) in iter::zip(upvars.keys(), places) {
                                     let var_name = tcx.hir().name(var_id);
-                                    struct_fmt.field(&var_name.as_str(), place);
+                                    struct_fmt.field(var_name.as_str(), place);
                                 }
                             }
 
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index f48e27e02cd..facd7abbc9d 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -338,7 +338,7 @@ impl<'tcx> CodegenUnit<'tcx> {
     }
 
     pub fn work_product_id(&self) -> WorkProductId {
-        WorkProductId::from_cgu_name(&self.name().as_str())
+        WorkProductId::from_cgu_name(self.name().as_str())
     }
 
     pub fn work_product(&self, tcx: TyCtxt<'_>) -> WorkProduct {
@@ -470,7 +470,7 @@ impl CodegenUnitNameBuilder<'tcx> {
         if self.tcx.sess.opts.debugging_opts.human_readable_cgu_names {
             cgu_name
         } else {
-            Symbol::intern(&CodegenUnit::mangle_name(&cgu_name.as_str()))
+            Symbol::intern(&CodegenUnit::mangle_name(cgu_name.as_str()))
         }
     }
 
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 175295b3199..d4e37fcf642 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -303,7 +303,7 @@ pub trait PrettyPrinter<'tcx>:
         match self.tcx().trimmed_def_paths(()).get(&def_id) {
             None => Ok((self, false)),
             Some(symbol) => {
-                self.write_str(&symbol.as_str())?;
+                self.write_str(symbol.as_str())?;
                 Ok((self, true))
             }
         }
diff --git a/compiler/rustc_monomorphize/src/partitioning/mod.rs b/compiler/rustc_monomorphize/src/partitioning/mod.rs
index cc60e7a1033..dc22ffc6747 100644
--- a/compiler/rustc_monomorphize/src/partitioning/mod.rs
+++ b/compiler/rustc_monomorphize/src/partitioning/mod.rs
@@ -366,7 +366,7 @@ fn collect_and_partition_mono_items<'tcx>(
         for cgu in codegen_units {
             tcx.prof.artifact_size(
                 "codegen_unit_size_estimate",
-                &cgu.name().as_str()[..],
+                cgu.name().as_str(),
                 cgu.size_estimate() as u64,
             );
         }
@@ -401,7 +401,7 @@ fn collect_and_partition_mono_items<'tcx>(
                 cgus.dedup();
                 for &(ref cgu_name, (linkage, _)) in cgus.iter() {
                     output.push(' ');
-                    output.push_str(&cgu_name.as_str());
+                    output.push_str(cgu_name.as_str());
 
                     let linkage_abbrev = match linkage {
                         Linkage::External => "External",
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 8a2ef296c76..3eef6160b73 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1608,7 +1608,7 @@ impl<'a> Parser<'a> {
                     next_token.kind
                 {
                     if self.token.span.hi() == next_token.span.lo() {
-                        let s = String::from("0.") + &symbol.as_str();
+                        let s = String::from("0.") + symbol.as_str();
                         let kind = TokenKind::lit(token::Float, Symbol::intern(&s), suffix);
                         return Some(Token::new(kind, self.token.span.to(next_token.span)));
                     }
@@ -1698,7 +1698,7 @@ impl<'a> Parser<'a> {
             LitError::InvalidFloatSuffix => {
                 let suf = suffix.expect("suffix error with no suffix");
                 let suf = suf.as_str();
-                if looks_like_width_suffix(&['f'], &suf) {
+                if looks_like_width_suffix(&['f'], suf) {
                     // If it looks like a width, try to be helpful.
                     let msg = format!("invalid width `{}` for float literal", &suf[1..]);
                     self.struct_span_err(span, &msg).help("valid widths are 32 and 64").emit();
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 49e6a7df103..aad7e8c3204 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -607,7 +607,7 @@ impl CheckAttrVisitor<'tcx> {
             return err_fn(meta.span(), &format!("isn't allowed on {}", err));
         }
         let item_name = self.tcx.hir().name(hir_id);
-        if &*item_name.as_str() == doc_alias {
+        if item_name.as_str() == doc_alias {
             return err_fn(meta.span(), "is the same as the item's name");
         }
         let span = meta.span();
@@ -636,7 +636,7 @@ impl CheckAttrVisitor<'tcx> {
                         LitKind::Str(s, _) => {
                             if !self.check_doc_alias_value(
                                 v,
-                                &s.as_str(),
+                                s.as_str(),
                                 hir_id,
                                 target,
                                 true,
diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs
index 3d7a215754a..dbdbefad4a9 100644
--- a/compiler/rustc_passes/src/liveness.rs
+++ b/compiler/rustc_passes/src/liveness.rs
@@ -1464,7 +1464,7 @@ impl<'tcx> Liveness<'_, 'tcx> {
         if name == kw::Empty {
             return None;
         }
-        let name: &str = &name.as_str();
+        let name = name.as_str();
         if name.as_bytes()[0] == b'_' {
             return None;
         }
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 3b1ca5db2cb..4254f3239f8 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -2340,7 +2340,7 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
                         _ => None,
                     });
                 }
-                suggest_existing(err, &name.as_str()[..], suggs);
+                suggest_existing(err, name.as_str(), suggs);
             }
             [] => {
                 let mut suggs = Vec::new();
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 662cb3aec15..c13545a67cc 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -693,7 +693,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
             intravisit::FnKind::Method(id, _, _) => id.name,
             intravisit::FnKind::Closure => sym::closure,
         };
-        let name: &str = name.as_str();
+        let name = name.as_str();
         let span = span!(Level::DEBUG, "visit_fn", name);
         let _enter = span.enter();
         match fk {
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 909a809b781..2046221ee6e 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -3482,7 +3482,7 @@ fn names_to_string(names: &[Symbol]) -> String {
         if Ident::with_dummy_span(*name).is_raw_guess() {
             result.push_str("r#");
         }
-        result.push_str(&name.as_str());
+        result.push_str(name.as_str());
     }
     result
 }
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index c7f8fe3a88a..99f932b4a27 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -825,7 +825,7 @@ impl<'tcx> SaveContext<'tcx> {
         for attr in attrs {
             if let Some(val) = attr.doc_str() {
                 // FIXME: Should save-analysis beautify doc strings itself or leave it to users?
-                result.push_str(&beautify_doc_string(val).as_str());
+                result.push_str(beautify_doc_string(val).as_str());
                 result.push('\n');
             }
         }
diff --git a/compiler/rustc_session/src/output.rs b/compiler/rustc_session/src/output.rs
index cc1e4bb198a..1277ab89899 100644
--- a/compiler/rustc_session/src/output.rs
+++ b/compiler/rustc_session/src/output.rs
@@ -60,7 +60,7 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
 
     if let Some(ref s) = sess.opts.crate_name {
         if let Some((attr, name)) = attr_crate_name {
-            if name.as_str() != *s {
+            if name.as_str() != s {
                 let msg = format!(
                     "`--crate-name` and `#[crate_name]` are \
                                    required to match, but `{}` != `{}`",
diff --git a/compiler/rustc_span/src/lev_distance.rs b/compiler/rustc_span/src/lev_distance.rs
index c10968e06d7..aed699e4839 100644
--- a/compiler/rustc_span/src/lev_distance.rs
+++ b/compiler/rustc_span/src/lev_distance.rs
@@ -55,7 +55,7 @@ pub fn find_best_match_for_name(
     lookup: Symbol,
     dist: Option<usize>,
 ) -> Option<Symbol> {
-    let lookup = &lookup.as_str();
+    let lookup = lookup.as_str();
     let max_dist = dist.unwrap_or_else(|| cmp::max(lookup.len(), 3) / 3);
 
     // Priority of matches:
@@ -70,7 +70,7 @@ pub fn find_best_match_for_name(
     let levenshtein_match = name_vec
         .iter()
         .filter_map(|&name| {
-            let dist = lev_distance(lookup, &name.as_str());
+            let dist = lev_distance(lookup, name.as_str());
             if dist <= max_dist { Some((name, dist)) } else { None }
         })
         // Here we are collecting the next structure:
@@ -88,7 +88,7 @@ pub fn find_best_match_for_name(
 
 fn find_match_by_sorted_words(iter_names: &[Symbol], lookup: &str) -> Option<Symbol> {
     iter_names.iter().fold(None, |result, candidate| {
-        if sort_by_words(&candidate.as_str()) == sort_by_words(lookup) {
+        if sort_by_words(candidate.as_str()) == sort_by_words(lookup) {
             Some(*candidate)
         } else {
             result
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index e879e42c2bd..51a7a2644f6 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1686,19 +1686,19 @@ impl Symbol {
 
 impl fmt::Debug for Symbol {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&self.as_str(), f)
+        fmt::Debug::fmt(self.as_str(), f)
     }
 }
 
 impl fmt::Display for Symbol {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(&self.as_str(), f)
+        fmt::Display::fmt(self.as_str(), f)
     }
 }
 
 impl<S: Encoder> Encodable<S> for Symbol {
     fn encode(&self, s: &mut S) -> Result<(), S::Error> {
-        s.emit_str(&self.as_str())
+        s.emit_str(self.as_str())
     }
 }
 
diff --git a/compiler/rustc_symbol_mangling/src/legacy.rs b/compiler/rustc_symbol_mangling/src/legacy.rs
index de18614360e..98ab085f33b 100644
--- a/compiler/rustc_symbol_mangling/src/legacy.rs
+++ b/compiler/rustc_symbol_mangling/src/legacy.rs
@@ -255,7 +255,7 @@ impl Printer<'tcx> for &mut SymbolPrinter<'tcx> {
     }
 
     fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
-        self.write_str(&self.tcx.crate_name(cnum).as_str())?;
+        self.write_str(self.tcx.crate_name(cnum).as_str())?;
         Ok(self)
     }
     fn path_qualified(
diff --git a/compiler/rustc_target/src/asm/mod.rs b/compiler/rustc_target/src/asm/mod.rs
index f1f5f4389e3..9128e54682f 100644
--- a/compiler/rustc_target/src/asm/mod.rs
+++ b/compiler/rustc_target/src/asm/mod.rs
@@ -298,43 +298,43 @@ impl InlineAsmReg {
         let name = name.as_str();
         Ok(match arch {
             InlineAsmArch::X86 | InlineAsmArch::X86_64 => {
-                Self::X86(X86InlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::X86(X86InlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Arm => {
-                Self::Arm(ArmInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Arm(ArmInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::AArch64 => {
-                Self::AArch64(AArch64InlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::AArch64(AArch64InlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::RiscV32 | InlineAsmArch::RiscV64 => {
-                Self::RiscV(RiscVInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::RiscV(RiscVInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Nvptx64 => {
-                Self::Nvptx(NvptxInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Nvptx(NvptxInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::PowerPC | InlineAsmArch::PowerPC64 => {
-                Self::PowerPC(PowerPCInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::PowerPC(PowerPCInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Hexagon => {
-                Self::Hexagon(HexagonInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Hexagon(HexagonInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Mips | InlineAsmArch::Mips64 => {
-                Self::Mips(MipsInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Mips(MipsInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::S390x => {
-                Self::S390x(S390xInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::S390x(S390xInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::SpirV => {
-                Self::SpirV(SpirVInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::SpirV(SpirVInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Wasm32 | InlineAsmArch::Wasm64 => {
-                Self::Wasm(WasmInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Wasm(WasmInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Bpf => {
-                Self::Bpf(BpfInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Bpf(BpfInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
             InlineAsmArch::Avr => {
-                Self::Avr(AvrInlineAsmReg::parse(arch, has_feature, target, &name)?)
+                Self::Avr(AvrInlineAsmReg::parse(arch, has_feature, target, name)?)
             }
         })
     }
@@ -798,7 +798,7 @@ impl InlineAsmClobberAbi {
         target: &Target,
         name: Symbol,
     ) -> Result<Self, &'static [&'static str]> {
-        let name = &*name.as_str();
+        let name = name.as_str();
         match arch {
             InlineAsmArch::X86 => match name {
                 "C" | "system" | "efiapi" | "cdecl" | "stdcall" | "fastcall" => {
diff --git a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
index 85ca4db7d74..4840995275a 100644
--- a/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/on_unimplemented.rs
@@ -269,7 +269,7 @@ impl<'tcx> OnUnimplementedFormatString {
         let name = tcx.item_name(trait_def_id);
         let generics = tcx.generics_of(trait_def_id);
         let s = self.0.as_str();
-        let parser = Parser::new(&s, None, None, false, ParseMode::Format);
+        let parser = Parser::new(s, None, None, false, ParseMode::Format);
         let mut result = Ok(());
         for token in parser {
             match token {
@@ -347,7 +347,7 @@ impl<'tcx> OnUnimplementedFormatString {
         let empty_string = String::new();
 
         let s = self.0.as_str();
-        let parser = Parser::new(&s, None, None, false, ParseMode::Format);
+        let parser = Parser::new(s, None, None, false, ParseMode::Format);
         let item_context = (options.get(&sym::ItemContext)).unwrap_or(&empty_string);
         parser
             .map(|p| match p {
diff --git a/compiler/rustc_typeck/src/check/generator_interior.rs b/compiler/rustc_typeck/src/check/generator_interior.rs
index 37e601fa404..d54b1d62ee9 100644
--- a/compiler/rustc_typeck/src/check/generator_interior.rs
+++ b/compiler/rustc_typeck/src/check/generator_interior.rs
@@ -609,7 +609,7 @@ fn check_must_not_suspend_def(
                     // Add optional reason note
                     if let Some(note) = attr.value_str() {
                         // FIXME(guswynn): consider formatting this better
-                        err.span_note(data.source_span, &note.as_str());
+                        err.span_note(data.source_span, note.as_str());
                     }
 
                     // Add some quick suggestions on what to do
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index ea86bafffb3..5e8b416168a 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -2846,7 +2846,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs {
             );
         } else if attr.has_name(sym::linkage) {
             if let Some(val) = attr.value_str() {
-                codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, &val.as_str()));
+                codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, id, val.as_str()));
             }
         } else if attr.has_name(sym::link_section) {
             if let Some(val) = attr.value_str() {
diff --git a/src/librustdoc/clean/cfg.rs b/src/librustdoc/clean/cfg.rs
index 9b5ca068486..dfee2b702c1 100644
--- a/src/librustdoc/clean/cfg.rs
+++ b/src/librustdoc/clean/cfg.rs
@@ -466,7 +466,7 @@ impl<'a> fmt::Display for Display<'a> {
                     (sym::unix, None) => "Unix",
                     (sym::windows, None) => "Windows",
                     (sym::debug_assertions, None) => "debug-assertions enabled",
-                    (sym::target_os, Some(os)) => match &*os.as_str() {
+                    (sym::target_os, Some(os)) => match os.as_str() {
                         "android" => "Android",
                         "dragonfly" => "DragonFly BSD",
                         "emscripten" => "Emscripten",
@@ -487,7 +487,7 @@ impl<'a> fmt::Display for Display<'a> {
                         "windows" => "Windows",
                         _ => "",
                     },
-                    (sym::target_arch, Some(arch)) => match &*arch.as_str() {
+                    (sym::target_arch, Some(arch)) => match arch.as_str() {
                         "aarch64" => "AArch64",
                         "arm" => "ARM",
                         "asmjs" => "JavaScript",
@@ -504,14 +504,14 @@ impl<'a> fmt::Display for Display<'a> {
                         "x86_64" => "x86-64",
                         _ => "",
                     },
-                    (sym::target_vendor, Some(vendor)) => match &*vendor.as_str() {
+                    (sym::target_vendor, Some(vendor)) => match vendor.as_str() {
                         "apple" => "Apple",
                         "pc" => "PC",
                         "sun" => "Sun",
                         "fortanix" => "Fortanix",
                         _ => "",
                     },
-                    (sym::target_env, Some(env)) => match &*env.as_str() {
+                    (sym::target_env, Some(env)) => match env.as_str() {
                         "gnu" => "GNU",
                         "msvc" => "MSVC",
                         "musl" => "musl",
@@ -545,14 +545,14 @@ impl<'a> fmt::Display for Display<'a> {
                         write!(
                             fmt,
                             r#"<code>{}="{}"</code>"#,
-                            Escape(&name.as_str()),
-                            Escape(&v.as_str())
+                            Escape(name.as_str()),
+                            Escape(v.as_str())
                         )
                     } else {
                         write!(fmt, r#"`{}="{}"`"#, name, v)
                     }
                 } else if self.1.is_html() {
-                    write!(fmt, "<code>{}</code>", Escape(&name.as_str()))
+                    write!(fmt, "<code>{}</code>", Escape(name.as_str()))
                 } else {
                     write!(fmt, "`{}`", name)
                 }
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 0ba4849ec2d..500c89b3fdc 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -201,7 +201,7 @@ impl ExternalCrate {
         // See if there's documentation generated into the local directory
         // WARNING: since rustdoc creates these directories as it generates documentation, this check is only accurate before rendering starts.
         // Make sure to call `location()` by that time.
-        let local_location = dst.join(&*self.name(tcx).as_str());
+        let local_location = dst.join(self.name(tcx).as_str());
         if local_location.is_dir() {
             return Local;
         }
diff --git a/src/librustdoc/formats/cache.rs b/src/librustdoc/formats/cache.rs
index d3831450e1d..5813062ceab 100644
--- a/src/librustdoc/formats/cache.rs
+++ b/src/librustdoc/formats/cache.rs
@@ -150,8 +150,7 @@ impl Cache {
 
             let name = e.name(tcx);
             let render_options = &cx.render_options;
-            let extern_url =
-                render_options.extern_html_root_urls.get(&*name.as_str()).map(|u| &**u);
+            let extern_url = render_options.extern_html_root_urls.get(name.as_str()).map(|u| &**u);
             let extern_url_takes_precedence = render_options.extern_html_root_takes_precedence;
             let dst = &render_options.output;
             let location = e.location(extern_url, extern_url_takes_precedence, dst, tcx);
diff --git a/src/librustdoc/formats/renderer.rs b/src/librustdoc/formats/renderer.rs
index b8ef3384c59..b7af8c9801f 100644
--- a/src/librustdoc/formats/renderer.rs
+++ b/src/librustdoc/formats/renderer.rs
@@ -90,7 +90,7 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
         // FIXME: checking `item.name.is_some()` is very implicit and leads to lots of special
         // cases. Use an explicit match instead.
         } else if item.name.is_some() && !item.is_extern_crate() {
-            prof.generic_activity_with_arg("render_item", &*item.name.unwrap_or(unknown).as_str())
+            prof.generic_activity_with_arg("render_item", item.name.unwrap_or(unknown).as_str())
                 .run(|| cx.item(item))?;
         }
     }
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 1bd4178c94a..a2771efc466 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -173,7 +173,7 @@ impl clean::GenericParamDef {
                 Ok(())
             }
             clean::GenericParamDefKind::Type { bounds, default, .. } => {
-                f.write_str(&*self.name.as_str())?;
+                f.write_str(self.name.as_str())?;
 
                 if !bounds.is_empty() {
                     if f.alternate() {
@@ -637,7 +637,7 @@ fn resolved_path<'cx>(
                 last.name.to_string()
             }
         } else {
-            anchor(did, &*last.name.as_str(), cx).to_string()
+            anchor(did, last.name.as_str(), cx).to_string()
         };
         write!(w, "{}{}", path, last.args.print(cx))?;
     }
@@ -772,7 +772,7 @@ fn fmt_type<'cx>(
         clean::Primitive(clean::PrimitiveType::Never) => {
             primitive_link(f, PrimitiveType::Never, "!", cx)
         }
-        clean::Primitive(prim) => primitive_link(f, prim, &*prim.as_sym().as_str(), cx),
+        clean::Primitive(prim) => primitive_link(f, prim, prim.as_sym().as_str(), cx),
         clean::BareFunction(ref decl) => {
             if f.alternate() {
                 write!(
@@ -1268,7 +1268,7 @@ impl clean::Visibility {
                     debug!("path={:?}", path);
                     // modified from `resolved_path()` to work with `DefPathData`
                     let last_name = path.data.last().unwrap().data.get_opt_name().unwrap();
-                    let anchor = anchor(vis_did, &last_name.as_str(), cx).to_string();
+                    let anchor = anchor(vis_did, last_name.as_str(), cx).to_string();
 
                     let mut s = "pub(in ".to_owned();
                     for seg in &path.data[..path.data.len() - 1] {
@@ -1417,7 +1417,7 @@ impl clean::TypeBinding {
         cx: &'a Context<'tcx>,
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         display_fn(move |f| {
-            f.write_str(&*self.name.as_str())?;
+            f.write_str(self.name.as_str())?;
             match self.kind {
                 clean::TypeBindingKind::Equality { ref ty } => {
                     if f.alternate() {
diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index 6a1c7c03063..c4d326e7711 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -180,7 +180,7 @@ impl<'tcx> Context<'tcx> {
     fn render_item(&self, it: &clean::Item, is_module: bool) -> String {
         let mut title = String::new();
         if !is_module {
-            title.push_str(&it.name.unwrap().as_str());
+            title.push_str(it.name.unwrap().as_str());
         }
         if !it.is_primitive() && !it.is_keyword() {
             if !is_module {
@@ -549,7 +549,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
 
     fn after_krate(&mut self) -> Result<(), Error> {
         let crate_name = self.tcx().crate_name(LOCAL_CRATE);
-        let final_file = self.dst.join(&*crate_name.as_str()).join("all.html");
+        let final_file = self.dst.join(crate_name.as_str()).join("all.html");
         let settings_file = self.dst.join("settings.html");
 
         let mut root_path = self.dst.to_str().expect("invalid path").to_owned();
@@ -619,9 +619,9 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         if let Some(ref redirections) = self.shared.redirections {
             if !redirections.borrow().is_empty() {
                 let redirect_map_path =
-                    self.dst.join(&*crate_name.as_str()).join("redirect-map.json");
+                    self.dst.join(crate_name.as_str()).join("redirect-map.json");
                 let paths = serde_json::to_string(&*redirections.borrow()).unwrap();
-                self.shared.ensure_dir(&self.dst.join(&*crate_name.as_str()))?;
+                self.shared.ensure_dir(&self.dst.join(crate_name.as_str()))?;
                 self.shared.fs.write(redirect_map_path, paths)?;
             }
         }
@@ -703,7 +703,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         if !buf.is_empty() {
             let name = item.name.as_ref().unwrap();
             let item_type = item.type_();
-            let file_name = &item_path(item_type, &name.as_str());
+            let file_name = &item_path(item_type, name.as_str());
             self.shared.ensure_dir(&self.dst)?;
             let joint_dst = self.dst.join(file_name);
             self.shared.fs.write(joint_dst, buf)?;
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index b2faf2d8b06..a8dafb6206c 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -640,9 +640,9 @@ fn short_item_info(
         // We display deprecation messages for #[deprecated] and #[rustc_deprecated]
         // but only display the future-deprecation messages for #[rustc_deprecated].
         let mut message = if let Some(since) = since {
-            let since = &since.as_str();
+            let since = since.as_str();
             if !stability::deprecation_in_effect(&depr) {
-                if *since == "TBD" {
+                if since == "TBD" {
                     String::from("Deprecating in a future Rust version")
                 } else {
                     format!("Deprecating in {}", Escape(since))
@@ -658,7 +658,7 @@ fn short_item_info(
             let note = note.as_str();
             let mut ids = cx.id_map.borrow_mut();
             let html = MarkdownHtml(
-                &note,
+                note,
                 &mut ids,
                 error_codes,
                 cx.shared.edition(),
@@ -683,7 +683,7 @@ fn short_item_info(
         let mut message =
             "<span class=\"emoji\">🔬</span> This is a nightly-only experimental API.".to_owned();
 
-        let mut feature = format!("<code>{}</code>", Escape(&feature.as_str()));
+        let mut feature = format!("<code>{}</code>", Escape(feature.as_str()));
         if let (Some(url), Some(issue)) = (&cx.shared.issue_tracker_base_url, issue) {
             feature.push_str(&format!(
                 "&nbsp;<a href=\"{url}{issue}\">#{issue}</a>",
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 5f96f4cd2c2..44a9ec5ea42 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -136,7 +136,7 @@ pub(super) fn print_item(
         page: page,
         static_root_path: page.get_static_root_path(),
         typ: typ,
-        name: &item.name.as_ref().unwrap().as_str(),
+        name: item.name.as_ref().unwrap().as_str(),
         item_type: &item.type_().to_string(),
         path_components: path_components,
         stability_since_raw: &stability_since_raw,
@@ -315,7 +315,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
                         w,
                         "<div class=\"item-left\"><code>{}extern crate {} as {};",
                         myitem.visibility.print_with_space(myitem.def_id, cx),
-                        anchor(myitem.def_id.expect_def_id(), &*src.as_str(), cx),
+                        anchor(myitem.def_id.expect_def_id(), src.as_str(), cx),
                         myitem.name.as_ref().unwrap(),
                     ),
                     None => write!(
@@ -324,7 +324,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
                         myitem.visibility.print_with_space(myitem.def_id, cx),
                         anchor(
                             myitem.def_id.expect_def_id(),
-                            &*myitem.name.as_ref().unwrap().as_str(),
+                            myitem.name.as_ref().unwrap().as_str(),
                             cx
                         ),
                     ),
@@ -405,7 +405,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
                     add = add,
                     stab = stab.unwrap_or_default(),
                     unsafety_flag = unsafety_flag,
-                    href = item_path(myitem.type_(), &myitem.name.unwrap().as_str()),
+                    href = item_path(myitem.type_(), myitem.name.unwrap().as_str()),
                     title = [full_path(cx, myitem), myitem.type_().to_string()]
                         .iter()
                         .filter_map(|s| if !s.is_empty() { Some(s.as_str()) } else { None })
@@ -1308,7 +1308,7 @@ fn item_struct(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::St
             document_non_exhaustive(w, it);
             for (index, (field, ty)) in fields.enumerate() {
                 let field_name =
-                    field.name.map_or_else(|| index.to_string(), |sym| (*sym.as_str()).to_string());
+                    field.name.map_or_else(|| index.to_string(), |sym| sym.as_str().to_string());
                 let id = cx.derive_id(format!("{}.{}", ItemType::StructField, field_name));
                 write!(
                     w,
@@ -1410,7 +1410,7 @@ crate fn compare_names(mut lhs: &str, mut rhs: &str) -> Ordering {
 pub(super) fn full_path(cx: &Context<'_>, item: &clean::Item) -> String {
     let mut s = cx.current.join("::");
     s.push_str("::");
-    s.push_str(&item.name.unwrap().as_str());
+    s.push_str(item.name.unwrap().as_str());
     s
 }
 
diff --git a/src/librustdoc/html/render/write_shared.rs b/src/librustdoc/html/render/write_shared.rs
index 0d5ba8e80d2..563f4ae7385 100644
--- a/src/librustdoc/html/render/write_shared.rs
+++ b/src/librustdoc/html/render/write_shared.rs
@@ -418,7 +418,7 @@ pub(super) fn write_shared(
         let dst = cx.dst.join(&format!("source-files{}.js", cx.shared.resource_suffix));
         let make_sources = || {
             let (mut all_sources, _krates) =
-                try_err!(collect(&dst, &krate.name(cx.tcx()).as_str(), "sourcesIndex"), &dst);
+                try_err!(collect(&dst, krate.name(cx.tcx()).as_str(), "sourcesIndex"), &dst);
             all_sources.push(format!(
                 "sourcesIndex[\"{}\"] = {};",
                 &krate.name(cx.tcx()),
@@ -437,7 +437,7 @@ pub(super) fn write_shared(
     // Update the search index and crate list.
     let dst = cx.dst.join(&format!("search-index{}.js", cx.shared.resource_suffix));
     let (mut all_indexes, mut krates) =
-        try_err!(collect_json(&dst, &krate.name(cx.tcx()).as_str()), &dst);
+        try_err!(collect_json(&dst, krate.name(cx.tcx()).as_str()), &dst);
     all_indexes.push(search_index);
     krates.push(krate.name(cx.tcx()).to_string());
     krates.sort();
@@ -575,7 +575,7 @@ pub(super) fn write_shared(
         mydst.push(&format!("{}.{}.js", remote_item_type, remote_path[remote_path.len() - 1]));
 
         let (mut all_implementors, _) =
-            try_err!(collect(&mydst, &krate.name(cx.tcx()).as_str(), "implementors"), &mydst);
+            try_err!(collect(&mydst, krate.name(cx.tcx()).as_str(), "implementors"), &mydst);
         all_implementors.push(implementors);
         // Sort the implementors by crate so the file will be generated
         // identically even with rustdoc running in parallel.
diff --git a/src/librustdoc/html/sources.rs b/src/librustdoc/html/sources.rs
index c8e93374e63..ba70ed8622a 100644
--- a/src/librustdoc/html/sources.rs
+++ b/src/librustdoc/html/sources.rs
@@ -19,7 +19,7 @@ use std::path::{Component, Path, PathBuf};
 crate fn render(cx: &mut Context<'_>, krate: &clean::Crate) -> Result<(), Error> {
     info!("emitting source files");
 
-    let dst = cx.dst.join("src").join(&*krate.name(cx.tcx()).as_str());
+    let dst = cx.dst.join("src").join(krate.name(cx.tcx()).as_str());
     cx.shared.ensure_dir(&dst)?;
 
     let mut collector = SourceCollector { dst, cx, emitted_local_sources: FxHashSet::default() };
diff --git a/src/tools/clippy/clippy_lints/src/attrs.rs b/src/tools/clippy/clippy_lints/src/attrs.rs
index 06a99ff5418..489945b513d 100644
--- a/src/tools/clippy/clippy_lints/src/attrs.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs.rs
@@ -486,7 +486,7 @@ fn check_attrs(cx: &LateContext<'_>, span: Span, name: Symbol, attrs: &[Attribut
 
 fn check_semver(cx: &LateContext<'_>, span: Span, lit: &Lit) {
     if let LitKind::Str(is, _) = lit.kind {
-        if Version::parse(&is.as_str()).is_ok() {
+        if Version::parse(is.as_str()).is_ok() {
             return;
         }
     }
@@ -619,7 +619,7 @@ fn check_mismatched_target_os(cx: &EarlyContext<'_>, attr: &Attribute) {
                     MetaItemKind::Word => {
                         if_chain! {
                             if let Some(ident) = meta.ident();
-                            if let Some(os) = find_os(&*ident.name.as_str());
+                            if let Some(os) = find_os(ident.name.as_str());
                             then {
                                 mismatched.push((os, ident.span));
                             }
diff --git a/src/tools/clippy/clippy_lints/src/booleans.rs b/src/tools/clippy/clippy_lints/src/booleans.rs
index 51835ee7488..43ad0f7605c 100644
--- a/src/tools/clippy/clippy_lints/src/booleans.rs
+++ b/src/tools/clippy/clippy_lints/src/booleans.rs
@@ -272,7 +272,7 @@ fn simplify_not(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
                 .copied()
                 .flat_map(|(a, b)| vec![(a, b), (b, a)])
                 .find(|&(a, _)| {
-                    let path: &str = &path.ident.name.as_str();
+                    let path: &str = path.ident.name.as_str();
                     a == path
                 })
                 .and_then(|(_, neg_method)| Some(format!("{}.{}()", snippet_opt(cx, args[0].span)?, neg_method)))
diff --git a/src/tools/clippy/clippy_lints/src/checked_conversions.rs b/src/tools/clippy/clippy_lints/src/checked_conversions.rs
index ffe6340bd77..31cc3698592 100644
--- a/src/tools/clippy/clippy_lints/src/checked_conversions.rs
+++ b/src/tools/clippy/clippy_lints/src/checked_conversions.rs
@@ -321,8 +321,8 @@ fn get_implementing_type<'a>(path: &QPath<'_>, candidates: &'a [&str], function:
         if let TyKind::Path(QPath::Resolved(None, tp)) = &ty.kind;
         if let [int] = &*tp.segments;
         then {
-            let name = &int.ident.name.as_str();
-            candidates.iter().find(|c| name == *c).copied()
+            let name = int.ident.name.as_str();
+            candidates.iter().find(|c| &name == *c).copied()
         } else {
             None
         }
@@ -335,8 +335,8 @@ fn int_ty_to_sym<'tcx>(path: &QPath<'_>) -> Option<&'tcx str> {
         if let QPath::Resolved(_, path) = *path;
         if let [ty] = &*path.segments;
         then {
-            let name = &ty.ident.name.as_str();
-            INTS.iter().find(|c| name == *c).copied()
+            let name = ty.ident.name.as_str();
+            INTS.iter().find(|c| &name == *c).copied()
         } else {
             None
         }
diff --git a/src/tools/clippy/clippy_lints/src/doc.rs b/src/tools/clippy/clippy_lints/src/doc.rs
index 2cdd59c5691..3650e4f91a0 100644
--- a/src/tools/clippy/clippy_lints/src/doc.rs
+++ b/src/tools/clippy/clippy_lints/src/doc.rs
@@ -437,7 +437,7 @@ fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs
 
     for attr in attrs {
         if let AttrKind::DocComment(comment_kind, comment) = attr.kind {
-            let (comment, current_spans) = strip_doc_comment_decoration(&comment.as_str(), comment_kind, attr.span);
+            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) {
diff --git a/src/tools/clippy/clippy_lints/src/enum_variants.rs b/src/tools/clippy/clippy_lints/src/enum_variants.rs
index fc3a35efaf8..689ac6184bf 100644
--- a/src/tools/clippy/clippy_lints/src/enum_variants.rs
+++ b/src/tools/clippy/clippy_lints/src/enum_variants.rs
@@ -153,7 +153,7 @@ fn check_variant(
             );
         }
     }
-    let first = &def.variants[0].ident.name.as_str();
+    let first = def.variants[0].ident.name.as_str();
     let mut pre = &first[..str_utils::camel_case_until(&*first).byte_index];
     let mut post = &first[str_utils::camel_case_start(&*first).byte_index..];
     for var in def.variants {
diff --git a/src/tools/clippy/clippy_lints/src/float_literal.rs b/src/tools/clippy/clippy_lints/src/float_literal.rs
index d30dede833c..6903073fbcd 100644
--- a/src/tools/clippy/clippy_lints/src/float_literal.rs
+++ b/src/tools/clippy/clippy_lints/src/float_literal.rs
@@ -68,7 +68,7 @@ impl<'tcx> LateLintPass<'tcx> for FloatLiteral {
             if let LitKind::Float(sym, lit_float_ty) = lit.node;
             then {
                 let sym_str = sym.as_str();
-                let formatter = FloatFormat::new(&sym_str);
+                let formatter = FloatFormat::new(sym_str);
                 // Try to bail out if the float is for sure fine.
                 // If its within the 2 decimal digits of being out of precision we
                 // check if the parsed representation is the same as the string
diff --git a/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs b/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
index 3df511ea8e7..5098ea349f9 100644
--- a/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
+++ b/src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs
@@ -696,7 +696,7 @@ impl<'tcx> LateLintPass<'tcx> for FloatingPointArithmetic {
             let recv_ty = cx.typeck_results().expr_ty(&args[0]);
 
             if recv_ty.is_floating_point() {
-                match &*path.ident.name.as_str() {
+                match path.ident.name.as_str() {
                     "ln" => check_ln1p(cx, expr, args),
                     "log" => check_log_base(cx, expr, args),
                     "powf" => check_powf(cx, expr, args),
diff --git a/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs b/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
index 968bbc524b2..0af6b3b7d46 100644
--- a/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
+++ b/src/tools/clippy/clippy_lints/src/iter_not_returning_iterator.rs
@@ -42,7 +42,7 @@ declare_lint_pass!(IterNotReturningIterator => [ITER_NOT_RETURNING_ITERATOR]);
 
 impl LateLintPass<'_> for IterNotReturningIterator {
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx ImplItem<'tcx>) {
-        let name: &str = &impl_item.ident.name.as_str();
+        let name = impl_item.ident.name.as_str();
         if_chain! {
             if let ImplItemKind::Fn(fn_sig, _) = &impl_item.kind;
             let ret_ty = return_ty(cx, impl_item.hir_id());
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs b/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
index 6f3acb45ba4..ba895f35faa 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_collect.rs
@@ -31,7 +31,7 @@ fn check_needless_collect_direct_usage<'tcx>(expr: &'tcx Expr<'_>, cx: &LateCont
             let ty = cx.typeck_results().expr_ty(&args[0]);
             let mut applicability = Applicability::MaybeIncorrect;
             let is_empty_sugg = "next().is_none()".to_string();
-            let method_name = &*method.ident.name.as_str();
+            let method_name = method.ident.name.as_str();
             let sugg = if is_type_diagnostic_item(cx, ty, sym::Vec) ||
                         is_type_diagnostic_item(cx, ty, sym::VecDeque) ||
                         is_type_diagnostic_item(cx, ty, sym::LinkedList) ||
@@ -210,7 +210,7 @@ impl<'tcx> Visitor<'tcx> for IterFunctionVisitor<'_, 'tcx> {
                     if let Some(hir_id) = self.current_statement_hir_id {
                         self.hir_id_uses_map.insert(hir_id, self.uses.len());
                     }
-                    match &*method_name.ident.name.as_str() {
+                    match method_name.ident.name.as_str() {
                         "into_iter" => self.uses.push(Some(IterFunction {
                             func: IterFunctionKind::IntoIter,
                             span: expr.span,
diff --git a/src/tools/clippy/clippy_lints/src/matches.rs b/src/tools/clippy/clippy_lints/src/matches.rs
index eacbfa54cf7..98acd1c1a75 100644
--- a/src/tools/clippy/clippy_lints/src/matches.rs
+++ b/src/tools/clippy/clippy_lints/src/matches.rs
@@ -966,7 +966,7 @@ fn check_wild_err_arm<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm
                         for pat in inner.iter() {
                             if let PatKind::Binding(_, id, ident, None) = pat.kind {
                                 if ident.as_str().starts_with('_') && !is_local_used(cx, arm.body, id) {
-                                    ident_bind_name = (&ident.name.as_str()).to_string();
+                                    ident_bind_name = ident.name.as_str().to_string();
                                     matching_wild = true;
                                 }
                             }
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs
index e1b1828f7fe..6ae334d9029 100644
--- a/src/tools/clippy/clippy_lints/src/methods/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs
@@ -2154,7 +2154,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
                 let self_ty = TraitRef::identity(cx.tcx, item.def_id.to_def_id()).self_ty().skip_binder();
                 wrong_self_convention::check(
                     cx,
-                    &item.ident.name.as_str(),
+                    item.ident.name.as_str(),
                     self_ty,
                     first_arg_ty,
                     first_arg_span,
diff --git a/src/tools/clippy/clippy_lints/src/missing_enforced_import_rename.rs b/src/tools/clippy/clippy_lints/src/missing_enforced_import_rename.rs
index 68d49e0f150..566e15ab2a6 100644
--- a/src/tools/clippy/clippy_lints/src/missing_enforced_import_rename.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_enforced_import_rename.rs
@@ -75,7 +75,7 @@ impl LateLintPass<'_> for ImportRename {
             if let Some(import) = match snip.split_once(" as ") {
                 None => Some(snip.as_str()),
                 Some((import, rename)) => {
-                    if rename.trim() == &*name.as_str() {
+                    if rename.trim() == name.as_str() {
                         None
                     } else {
                         Some(import.trim())
diff --git a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
index 5559fac0a8a..25fbcb3c609 100644
--- a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
+++ b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
@@ -224,14 +224,14 @@ impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
             match existing_name.len.cmp(&count) {
                 Ordering::Greater => {
                     if existing_name.len - count != 1
-                        || levenstein_not_1(&interned_name, &existing_name.interned.as_str())
+                        || levenstein_not_1(&interned_name, existing_name.interned.as_str())
                     {
                         continue;
                     }
                 },
                 Ordering::Less => {
                     if count - existing_name.len != 1
-                        || levenstein_not_1(&existing_name.interned.as_str(), &interned_name)
+                        || levenstein_not_1(existing_name.interned.as_str(), &interned_name)
                     {
                         continue;
                     }
diff --git a/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs b/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
index a04d589f880..4722c031006 100644
--- a/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
+++ b/src/tools/clippy/clippy_lints/src/nonstandard_macro_braces.rs
@@ -104,7 +104,7 @@ fn is_offending_macro<'a>(cx: &EarlyContext<'_>, span: Span, mac_braces: &'a Mac
     };
     if_chain! {
         if let ExpnKind::Macro(MacroKind::Bang, mac_name) = span.ctxt().outer_expn_data().kind;
-        let name = &*mac_name.as_str();
+        let name = mac_name.as_str();
         if let Some(braces) = mac_braces.macro_braces.get(name);
         if let Some(snip) = snippet_opt(cx, span.ctxt().outer_expn_data().call_site);
         // we must check only invocation sites
diff --git a/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs b/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs
index 8ebee9bd04d..e58ca95fa04 100644
--- a/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs
+++ b/src/tools/clippy/clippy_lints/src/path_buf_push_overwrite.rs
@@ -53,7 +53,7 @@ impl<'tcx> LateLintPass<'tcx> for PathBufPushOverwrite {
             if let Some(get_index_arg) = args.get(1);
             if let ExprKind::Lit(ref lit) = get_index_arg.kind;
             if let LitKind::Str(ref path_lit, _) = lit.node;
-            if let pushed_path = Path::new(&*path_lit.as_str());
+            if let pushed_path = Path::new(path_lit.as_str());
             if let Some(pushed_path_lit) = pushed_path.to_str();
             if pushed_path.has_root();
             if let Some(root) = pushed_path.components().next();
diff --git a/src/tools/clippy/clippy_lints/src/regex.rs b/src/tools/clippy/clippy_lints/src/regex.rs
index 8e5983b4773..b6d04334de9 100644
--- a/src/tools/clippy/clippy_lints/src/regex.rs
+++ b/src/tools/clippy/clippy_lints/src/regex.rs
@@ -150,7 +150,7 @@ fn check_regex<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, utf8: bool) {
 
     if let ExprKind::Lit(ref lit) = expr.kind {
         if let LitKind::Str(ref r, style) = lit.node {
-            let r = &r.as_str();
+            let r = r.as_str();
             let offset = if let StrStyle::Raw(n) = style { 2 + n } else { 1 };
             match parser.parse(r) {
                 Ok(r) => {
diff --git a/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs b/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs
index 953d21e07a3..20e38dc564e 100644
--- a/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs
+++ b/src/tools/clippy/clippy_lints/src/stable_sort_primitive.rs
@@ -89,7 +89,7 @@ fn detect_stable_sort_primitive(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option
     if_chain! {
         if let ExprKind::MethodCall(method_name, _, args, _) = &expr.kind;
         if let Some(slice) = &args.get(0);
-        if let Some(method) = SortingKind::from_stable_name(&method_name.ident.name.as_str());
+        if let Some(method) = SortingKind::from_stable_name(method_name.ident.name.as_str());
         if let Some(slice_type) = is_slice_of_primitives(cx, slice);
         then {
             let args_str = args.iter().skip(1).map(|arg| Sugg::hir(cx, arg, "..").to_string()).collect::<Vec<String>>().join(", ");
diff --git a/src/tools/clippy/clippy_lints/src/strings.rs b/src/tools/clippy/clippy_lints/src/strings.rs
index 368274440d5..60f0ffde094 100644
--- a/src/tools/clippy/clippy_lints/src/strings.rs
+++ b/src/tools/clippy/clippy_lints/src/strings.rs
@@ -330,7 +330,7 @@ impl<'tcx> LateLintPass<'tcx> for StringLitAsBytes {
             if let ExprKind::MethodCall(path, _, [recv], _) = &e.kind;
             if path.ident.name == sym!(into_bytes);
             if let ExprKind::MethodCall(path, _, [recv], _) = &recv.kind;
-            if matches!(&*path.ident.name.as_str(), "to_owned" | "to_string");
+            if matches!(path.ident.name.as_str(), "to_owned" | "to_string");
             if let ExprKind::Lit(lit) = &recv.kind;
             if let LitKind::Str(lit_content, _) = &lit.node;
 
diff --git a/src/tools/clippy/clippy_lints/src/unit_types/unit_cmp.rs b/src/tools/clippy/clippy_lints/src/unit_types/unit_cmp.rs
index 85257f3113c..6d9aff47421 100644
--- a/src/tools/clippy/clippy_lints/src/unit_types/unit_cmp.rs
+++ b/src/tools/clippy/clippy_lints/src/unit_types/unit_cmp.rs
@@ -12,7 +12,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 if let ExprKind::Binary(ref cmp, left, _) = expr.kind {
                     let op = cmp.node;
                     if op.is_comparison() && cx.typeck_results().expr_ty(left).is_unit() {
-                        let result = match &*symbol.as_str() {
+                        let result = match symbol.as_str() {
                             "assert_eq" | "debug_assert_eq" => "succeed",
                             "assert_ne" | "debug_assert_ne" => "fail",
                             _ => return,
diff --git a/src/tools/clippy/clippy_lints/src/unused_unit.rs b/src/tools/clippy/clippy_lints/src/unused_unit.rs
index 48c17fa2a40..bfd17a68749 100644
--- a/src/tools/clippy/clippy_lints/src/unused_unit.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_unit.rs
@@ -94,7 +94,7 @@ impl EarlyLintPass for UnusedUnit {
 
         if_chain! {
             if segments.len() == 1;
-            if ["Fn", "FnMut", "FnOnce"].contains(&&*segments[0].ident.name.as_str());
+            if ["Fn", "FnMut", "FnOnce"].contains(&segments[0].ident.name.as_str());
             if let Some(args) = &segments[0].args;
             if let ast::GenericArgs::Parenthesized(generic_args) = &**args;
             if let ast::FnRetTy::Ty(ty) = &generic_args.output;
diff --git a/src/tools/clippy/clippy_lints/src/write.rs b/src/tools/clippy/clippy_lints/src/write.rs
index 5bf0cffdbad..f9add927b49 100644
--- a/src/tools/clippy/clippy_lints/src/write.rs
+++ b/src/tools/clippy/clippy_lints/src/write.rs
@@ -371,9 +371,9 @@ impl EarlyLintPass for Write {
 /// Return this and a boolean indicating whether it only consisted of a newline.
 fn newline_span(fmtstr: &StrLit) -> (Span, bool) {
     let sp = fmtstr.span;
-    let contents = &fmtstr.symbol.as_str();
+    let contents = fmtstr.symbol.as_str();
 
-    if *contents == r"\n" {
+    if contents == r"\n" {
         return (sp, true);
     }
 
@@ -484,7 +484,7 @@ impl Write {
             StrStyle::Raw(n) => Some(n as usize),
         };
 
-        let mut parser = Parser::new(&str_sym, style, snippet_opt(cx, str_lit.span), false, ParseMode::Format);
+        let mut parser = Parser::new(str_sym, style, snippet_opt(cx, str_lit.span), false, ParseMode::Format);
         let mut args = SimpleFormatArgs::default();
 
         while let Some(arg) = parser.next() {
@@ -589,7 +589,7 @@ impl Write {
                     lit.token.symbol.as_str().replace('{', "{{").replace('}', "}}")
                 },
                 LitKind::StrRaw(_) | LitKind::Str | LitKind::ByteStrRaw(_) | LitKind::ByteStr => continue,
-                LitKind::Byte | LitKind::Char => match &*lit.token.symbol.as_str() {
+                LitKind::Byte | LitKind::Char => match lit.token.symbol.as_str() {
                     "\"" if matches!(fmtstr.style, StrStyle::Cooked) => "\\\"",
                     "\"" if matches!(fmtstr.style, StrStyle::Raw(0)) => continue,
                     "\\\\" if matches!(fmtstr.style, StrStyle::Raw(_)) => "\\",
@@ -671,7 +671,7 @@ fn check_newlines(fmtstr: &StrLit) -> bool {
     let mut last_was_cr = false;
     let mut should_lint = false;
 
-    let contents = &fmtstr.symbol.as_str();
+    let contents = fmtstr.symbol.as_str();
 
     let mut cb = |r: Range<usize>, c: Result<char, EscapeError>| {
         let c = c.unwrap();
diff --git a/src/tools/clippy/clippy_utils/src/attrs.rs b/src/tools/clippy/clippy_utils/src/attrs.rs
index 7ae9615d560..25a84d16650 100644
--- a/src/tools/clippy/clippy_utils/src/attrs.rs
+++ b/src/tools/clippy/clippy_utils/src/attrs.rs
@@ -113,7 +113,7 @@ pub fn get_attr<'a>(
 fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'static str, mut f: F) {
     for attr in get_attr(sess, attrs, name) {
         if let Some(ref value) = attr.value_str() {
-            if let Ok(value) = FromStr::from_str(&value.as_str()) {
+            if let Ok(value) = FromStr::from_str(value.as_str()) {
                 f(value);
             } else {
                 sess.span_err(attr.span, "not a number");
diff --git a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
index c2645ac730a..61e529a6079 100644
--- a/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
+++ b/src/tools/clippy/clippy_utils/src/eager_or_lazy.rs
@@ -47,7 +47,7 @@ impl ops::BitOrAssign for EagernessSuggestion {
 /// Determine the eagerness of the given function call.
 fn fn_eagerness(cx: &LateContext<'tcx>, fn_id: DefId, name: Symbol, args: &'tcx [Expr<'_>]) -> EagernessSuggestion {
     use EagernessSuggestion::{Eager, Lazy, NoChange};
-    let name = &*name.as_str();
+    let name = name.as_str();
 
     let ty = match cx.tcx.impl_of_method(fn_id) {
         Some(id) => cx.tcx.type_of(id),
diff --git a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
index e6d8ba3f02e..1a4da1627b7 100644
--- a/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
+++ b/src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
@@ -372,7 +372,7 @@ fn is_const_fn(tcx: TyCtxt<'_>, def_id: DefId, msrv: Option<&RustcVersion>) -> b
                 // as a part of an unimplemented MSRV check https://github.com/rust-lang/rust/issues/65262.
                 crate::meets_msrv(
                     msrv,
-                    &RustcVersion::parse(&since.as_str())
+                    &RustcVersion::parse(since.as_str())
                         .expect("`rustc_attr::StabilityLevel::Stable::since` is ill-formatted"),
                 )
             } else {
diff --git a/src/tools/rustfmt/src/attr.rs b/src/tools/rustfmt/src/attr.rs
index 76b66e9da80..3887a8051f2 100644
--- a/src/tools/rustfmt/src/attr.rs
+++ b/src/tools/rustfmt/src/attr.rs
@@ -337,7 +337,7 @@ impl Rewrite for ast::Attribute {
         } else {
             let should_skip = self
                 .ident()
-                .map(|s| context.skip_context.skip_attribute(&s.name.as_str()))
+                .map(|s| context.skip_context.skip_attribute(s.name.as_str()))
                 .unwrap_or(false);
             let prefix = attr_prefix(self);
 
@@ -356,7 +356,7 @@ impl Rewrite for ast::Attribute {
 
                         let literal_str = literal.as_str();
                         let doc_comment_formatter =
-                            DocCommentFormatter::new(&*literal_str, comment_style);
+                            DocCommentFormatter::new(literal_str, comment_style);
                         let doc_comment = format!("{}", doc_comment_formatter);
                         return rewrite_doc_comment(
                             &doc_comment,
diff --git a/src/tools/rustfmt/src/modules.rs b/src/tools/rustfmt/src/modules.rs
index b1f229d9daa..6cfe91c597a 100644
--- a/src/tools/rustfmt/src/modules.rs
+++ b/src/tools/rustfmt/src/modules.rs
@@ -455,7 +455,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
 
     fn push_inline_mod_directory(&mut self, id: symbol::Ident, attrs: &[ast::Attribute]) {
         if let Some(path) = find_path_value(attrs) {
-            self.directory.path.push(&*path.as_str());
+            self.directory.path.push(path.as_str());
             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
         } else {
             // We have to push on the current module name in the case of relative
diff --git a/src/tools/rustfmt/src/utils.rs b/src/tools/rustfmt/src/utils.rs
index 3a8713c5bdb..0c0b789a6ef 100644
--- a/src/tools/rustfmt/src/utils.rs
+++ b/src/tools/rustfmt/src/utils.rs
@@ -260,7 +260,7 @@ fn is_skip(meta_item: &MetaItem) -> bool {
     match meta_item.kind {
         MetaItemKind::Word => {
             let path_str = pprust::path_to_string(&meta_item.path);
-            path_str == *skip_annotation().as_str() || path_str == *depr_skip_annotation().as_str()
+            path_str == skip_annotation().as_str() || path_str == depr_skip_annotation().as_str()
         }
         MetaItemKind::List(ref l) => {
             meta_item.has_name(sym::cfg_attr) && l.len() == 2 && is_skip_nested(&l[1])