Remove unnecessary .to_string()/.as_str()s

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -2440,7 +2440,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                         "consider consuming the `{ty}` when turning it into an \
                                          `Iterator`",
                                     ),
-                                    "into_iter".to_string(),
+                                    "into_iter",
                                     Applicability::MaybeIncorrect,
                                 );
                             }

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -924,7 +924,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         err.span_suggestion_verbose(
                             expr.span.shrink_to_lo(),
                             "use a mutable iterator instead",
-                            "mut ".to_string(),
+                            "mut ",
                             Applicability::MachineApplicable,
                         );
                     }

compiler/rustc_hir_analysis/src/astconv/errors.rs

@@ -247,7 +247,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         err.span_suggestion_verbose(
                             assoc_name.span,
                             fluent::hir_analysis_assoc_item_not_found_similar_in_other_trait_with_bound_sugg,
-                            suggested_name.to_string(),
+                            suggested_name,
                             Applicability::MaybeIncorrect,
                         );
                     }

compiler/rustc_hir_typeck/src/expr.rs

@@ -1000,7 +1000,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             err.span_suggestion_verbose(
                 lhs.span.shrink_to_hi(),
                 "you might have meant to write a semicolon here",
-                ";".to_string(),
+                ";",
                 Applicability::MachineApplicable,
             );
             return true;

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -1116,9 +1116,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                         item_name.span,
                                         format!(
                                             "you might have meant to use `{}`",
-                                            inherent_method.name.as_str()
+                                            inherent_method.name
                                         ),
-                                        inherent_method.name.as_str(),
+                                        inherent_method.name,
                                         Applicability::MaybeIncorrect,
                                     );
                                     break 'outer;
@@ -2019,7 +2019,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 diag.span_suggestion_verbose(
                     sm.span_extend_while(seg1.ident.span.shrink_to_hi(), |c| c == ':').unwrap(),
                     "you may have meant to call an instance method",
-                    ".".to_string(),
+                    ".",
                     Applicability::MaybeIncorrect,
                 );
             }

compiler/rustc_parse/src/parser/expr.rs

@@ -3288,7 +3288,7 @@ impl<'a> Parser<'a> {
                         } else {
                             Applicability::MaybeIncorrect
                         };
-                        err.span_suggestion_verbose(sugg_sp, msg, "=> ".to_string(), applicability);
+                        err.span_suggestion_verbose(sugg_sp, msg, "=> ", applicability);
                     }
                 }
                 err

compiler/rustc_parse/src/parser/generics.rs

@@ -148,7 +148,7 @@ impl<'a> Parser<'a> {
             .with_span_suggestion_verbose(
                 mistyped_const_ident.span,
                 "use the `const` keyword",
-                kw::Const.as_str(),
+                kw::Const,
                 Applicability::MachineApplicable,
             )
             .emit();

compiler/rustc_parse/src/parser/item.rs

@@ -1453,7 +1453,7 @@ impl<'a> Parser<'a> {
                                 err.span_suggestion_verbose(
                                     prev_span,
                                     "perhaps you meant to use `struct` here",
-                                    "struct".to_string(),
+                                    "struct",
                                     Applicability::MaybeIncorrect,
                                 );
                             }

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -699,7 +699,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         err.span_suggestion_verbose(
                             span.shrink_to_lo(),
                             msg,
-                            "self.".to_string(),
+                            "self.",
                             Applicability::MachineApplicable,
                         );
                     }
@@ -710,7 +710,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                         err.span_suggestion_verbose(
                             span.shrink_to_lo(),
                             format!("you might have meant to {}", candidate.action()),
-                            "Self::".to_string(),
+                            "Self::",
                             Applicability::MachineApplicable,
                         );
                     }

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1288,7 +1288,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             err.span_suggestion_verbose(
                 obligation.cause.span.shrink_to_hi(),
                 "consider using clone here",
-                ".clone()".to_string(),
+                ".clone()",
                 Applicability::MaybeIncorrect,
             );
             return true;
@@ -3245,7 +3245,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                             err.span_suggestion_verbose(
                                 span,
                                 "you can use `impl Trait` as the argument type",
-                                "impl ".to_string(),
+                                "impl ",
                                 Applicability::MaybeIncorrect,
                             );
                             let sugg = if !needs_parens {
@@ -5203,7 +5203,7 @@ fn point_at_assoc_type_restriction(
                     err.span_suggestion_verbose(
                         path.span,
                         "replace the associated type with the type specified in this `impl`",
-                        tcx.type_of(new.def_id).skip_binder().to_string(),
+                        tcx.type_of(new.def_id).skip_binder(),
                         Applicability::MachineApplicable,
                     );
                 }