Rollup merge of rust-lang#98043 - TaKO8Ki:remove-unnecessary-to-string, r=davidtwco

Remove unnecessary `to_string` and `String::new`

rust-lang@73fa217 changed the type of the `suggestion` argument to `impl ToString`. This patch removes unnecessary `to_string` and `String::new`.

cc: `````@davidtwco`````

Author: matthiaskrgr

compiler/rustc_ast_lowering/src/expr.rs

@@ -1168,7 +1168,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                             .span_suggestion(
                                 e.span,
                                 "consider removing the trailing pattern",
-                                String::new(),
+                                "",
                                 rustc_errors::Applicability::MachineApplicable,
                             )
                             .emit();

compiler/rustc_ast_lowering/src/pat.rs

@@ -139,7 +139,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         .span_suggestion_verbose(
                             sp,
                             &format!("if you don't need to use the contents of {}, discard the tuple's remaining fields", ident),
-                            "..".to_string(),
+                            "..",
                             Applicability::MaybeIncorrect,
                         )
                         .emit();

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -488,7 +488,7 @@ impl<'a> AstValidator<'a> {
             .span_suggestion(
                 replace_span,
                 &format!("provide a definition for the {}", ctx),
-                sugg.to_string(),
+                sugg,
                 Applicability::HasPlaceholders,
             )
             .emit();
@@ -522,7 +522,7 @@ impl<'a> AstValidator<'a> {
                 .span_suggestion(
                     span,
                     &format!("remove the {}", remove_descr),
-                    String::new(),
+                    "",
                     Applicability::MaybeIncorrect,
                 )
                 .span_label(self.current_extern_span(), "`extern` block begins here")
@@ -570,7 +570,7 @@ impl<'a> AstValidator<'a> {
             .span_suggestion(
                 body.span,
                 "remove the invalid body",
-                ";".to_string(),
+                ";",
                 Applicability::MaybeIncorrect,
             )
             .help(
@@ -599,7 +599,7 @@ impl<'a> AstValidator<'a> {
                 .span_suggestion_verbose(
                     span.until(ident.span.shrink_to_lo()),
                     "remove the qualifiers",
-                    "fn ".to_string(),
+                    "fn ",
                     Applicability::MaybeIncorrect,
                 )
                 .emit();
@@ -703,7 +703,7 @@ impl<'a> AstValidator<'a> {
             .span_suggestion(
                 generics.span,
                 "remove the parameters",
-                String::new(),
+                "",
                 Applicability::MachineApplicable,
             )
             .emit();
@@ -721,7 +721,7 @@ impl<'a> AstValidator<'a> {
         .span_suggestion(
             span,
             "remove the super traits or lifetime bounds",
-            String::new(),
+            "",
             Applicability::MachineApplicable,
         )
         .emit();
@@ -753,7 +753,7 @@ impl<'a> AstValidator<'a> {
             .span_suggestion(
                 total_span,
                 "remove these associated items",
-                String::new(),
+                "",
                 Applicability::MachineApplicable,
             )
             .span_label(ident_span, "auto trait cannot have associated items")
@@ -993,7 +993,7 @@ fn validate_generic_param_order(
             err.span_suggestion(
                 span,
                 "reorder the parameters: lifetimes, then consts and types",
-                ordered_params.clone(),
+                &ordered_params,
                 Applicability::MachineApplicable,
             );
             err.emit();

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -823,7 +823,7 @@ fn maybe_stage_features(sess: &Session, krate: &ast::Crate) {
                 err.span_suggestion(
                     attr.span,
                     "remove the attribute",
-                    String::new(),
+                    "",
                     Applicability::MachineApplicable,
                 );
             }

compiler/rustc_attr/src/builtin.rs

@@ -59,7 +59,7 @@ fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
                     err.span_suggestion(
                         span,
                         "consider removing the prefix",
-                        lint_str[1..].to_string(),
+                        &lint_str[1..],
                         Applicability::MaybeIncorrect,
                     );
                 }
@@ -942,7 +942,7 @@ pub fn parse_repr_attr(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                         err.span_suggestion(
                             item.span(),
                             "supply an argument here",
-                            "align(...)".to_string(),
+                            "align(...)",
                             Applicability::HasPlaceholders,
                         );
                         err.emit();

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -225,7 +225,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     .map(|n| format!("`{}`", n))
                                     .unwrap_or_else(|| "the value".to_string())
                             ),
-                            "ref ".to_string(),
+                            "ref ",
                             Applicability::MachineApplicable,
                         );
                         in_pattern = true;
@@ -276,7 +276,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 .map(|n| format!("`{}`", n))
                                 .unwrap_or_else(|| "the mutable reference".to_string()),
                         ),
-                        "&mut *".to_string(),
+                        "&mut *",
                         Applicability::MachineApplicable,
                     );
                 }
@@ -1519,15 +1519,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             Ok(string) => {
                 if string.starts_with("async ") {
                     let pos = args_span.lo() + BytePos(6);
-                    (args_span.with_lo(pos).with_hi(pos), "move ".to_string())
+                    (args_span.with_lo(pos).with_hi(pos), "move ")
                 } else if string.starts_with("async|") {
                     let pos = args_span.lo() + BytePos(5);
-                    (args_span.with_lo(pos).with_hi(pos), " move".to_string())
+                    (args_span.with_lo(pos).with_hi(pos), " move")
                 } else {
-                    (args_span.shrink_to_lo(), "move ".to_string())
+                    (args_span.shrink_to_lo(), "move ")
                 }
             }
-            Err(_) => (args_span, "move |<args>| <body>".to_string()),
+            Err(_) => (args_span, "move |<args>| <body>"),
         };
         let kind = match use_span.generator_kind() {
             Some(generator_kind) => match generator_kind {

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -212,7 +212,7 @@ impl<'tcx> BorrowExplanation<'tcx> {
                                         "consider adding semicolon after the expression so its \
                                         temporaries are dropped sooner, before the local variables \
                                         declared by the block are dropped",
-                                        ";".to_string(),
+                                        ";",
                                         Applicability::MaybeIncorrect,
                                     );
                                 }

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -1023,7 +1023,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                      avoid moving into the `for` loop",
                                     ty,
                                 ),
-                                "&".to_string(),
+                                "&",
                                 Applicability::MaybeIncorrect,
                             );
                         }
@@ -1049,7 +1049,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                             .map(|n| format!("`{}`", n))
                                             .unwrap_or_else(|| "the mutable reference".to_string()),
                                     ),
-                                    "&mut *".to_string(),
+                                    "&mut *",
                                     Applicability::MachineApplicable,
                                 );
                             }
@@ -1067,7 +1067,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         err.span_suggestion_verbose(
                             fn_call_span.shrink_to_lo(),
                             "consider calling `.as_ref()` to borrow the type's contents",
-                            "as_ref().".to_string(),
+                            "as_ref().",
                             Applicability::MachineApplicable,
                         );
                     }

compiler/rustc_borrowck/src/diagnostics/move_errors.rs

@@ -417,7 +417,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             err.span_suggestion_verbose(
                 span.shrink_to_hi(),
                 &format!("consider borrowing the `{}`'s content", diag_name.unwrap()),
-                ".as_ref()".to_string(),
+                ".as_ref()",
                 Applicability::MaybeIncorrect,
             );
         } else if let Some(use_spans) = use_spans {

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -295,7 +295,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                             err.span_suggestion_verbose(
                                 source_info.span.with_hi(source_info.span.lo() + BytePos(5)),
                                 "try removing `&mut` here",
-                                String::new(),
+                                "",
                                 Applicability::MachineApplicable,
                             );
                         } else {
@@ -316,7 +316,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     err.span_suggestion_verbose(
                         decl.source_info.span.shrink_to_lo(),
                         "consider making the binding mutable",
-                        "mut ".to_string(),
+                        "mut ",
                         Applicability::MachineApplicable,
                     );
                 }
@@ -402,7 +402,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 err.span_suggestion(
                     span,
                     "try removing `&mut` here",
-                    String::new(),
+                    "",
                     Applicability::MaybeIncorrect,
                 );
             }