Remove unneeded calls to format!()

src/librustc_driver/lib.rs

@@ -601,7 +601,7 @@ impl RustcDefaultCalls {
             });
             compiler.codegen_backend().link(&sess, Box::new(codegen_results), &outputs)
         } else {
-            sess.fatal(&format!("rlink must be a file"))
+            sess.fatal("rlink must be a file")
         }
     }
 

src/librustc_expand/expand.rs

@@ -1664,10 +1664,9 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
                         }
                     }
                 } else {
-                    let mut err = self.cx.struct_span_err(
-                        it.span(),
-                        &format!("expected path to external documentation"),
-                    );
+                    let mut err = self
+                        .cx
+                        .struct_span_err(it.span(), "expected path to external documentation");
 
                     // Check if the user erroneously used `doc(include(...))` syntax.
                     let literal = it.meta_item_list().and_then(|list| {

src/librustc_incremental/assert_module_sources.rs

@@ -81,10 +81,7 @@ impl AssertModuleSource<'tcx> {
         if !self.tcx.sess.opts.debugging_opts.query_dep_graph {
             self.tcx.sess.span_fatal(
                 attr.span,
-                &format!(
-                    "found CGU-reuse attribute but `-Zquery-dep-graph` \
-                          was not specified"
-                ),
+                "found CGU-reuse attribute but `-Zquery-dep-graph` was not specified",
             );
         }
 

src/librustc_incremental/persist/dirty_clean.rs

@@ -537,10 +537,7 @@ impl FindAllAttrs<'tcx> {
             if !checked_attrs.contains(&attr.id) {
                 self.tcx.sess.span_err(
                     attr.span,
-                    &format!(
-                        "found unchecked \
-                    `#[rustc_dirty]` / `#[rustc_clean]` attribute"
-                    ),
+                    "found unchecked `#[rustc_dirty]` / `#[rustc_clean]` attribute",
                 );
             }
         }

src/librustc_infer/traits/coherence.rs

@@ -39,10 +39,10 @@ pub struct OverlapResult<'tcx> {
 }
 
 pub fn add_placeholder_note(err: &mut rustc_errors::DiagnosticBuilder<'_>) {
-    err.note(&format!(
+    err.note(
         "this behavior recently changed as a result of a bug fix; \
-         see rust-lang/rust#56105 for details"
-    ));
+         see rust-lang/rust#56105 for details",
+    );
 }
 
 /// If there are types that satisfy both impls, invokes `on_overlap`

src/librustc_infer/traits/error_reporting/mod.rs

@@ -935,9 +935,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
             // Already reported in the query.
             ConstEvalFailure(ErrorHandled::Reported) => {
-                self.tcx
-                    .sess
-                    .delay_span_bug(span, &format!("constant in type had an ignored error"));
+                self.tcx.sess.delay_span_bug(span, "constant in type had an ignored error");
                 return;
             }
 

src/librustc_metadata/creader.rs

@@ -680,10 +680,7 @@ impl<'a> CrateLoader<'a> {
 
             // Sanity check the loaded crate to ensure it is indeed a profiler runtime
             if !data.is_profiler_runtime() {
-                self.sess.err(&format!(
-                    "the crate `profiler_builtins` is not \
-                                        a profiler runtime"
-                ));
+                self.sess.err("the crate `profiler_builtins` is not a profiler runtime");
             }
         }
     }

src/librustc_mir/transform/check_consts/ops.rs

@@ -65,10 +65,8 @@ impl NonConstOp for Downcast {
 pub struct FnCallIndirect;
 impl NonConstOp for FnCallIndirect {
     fn emit_error(&self, item: &Item<'_, '_>, span: Span) {
-        let mut err = item
-            .tcx
-            .sess
-            .struct_span_err(span, &format!("function pointers are not allowed in const fn"));
+        let mut err =
+            item.tcx.sess.struct_span_err(span, "function pointers are not allowed in const fn");
         err.emit();
     }
 }

src/librustc_parse/parser/generics.rs

@@ -121,15 +121,12 @@ impl<'a> Parser<'a> {
                         .span_label(attrs[0].span, "attributes must go before parameters")
                         .emit();
                     } else {
-                        self.struct_span_err(
-                            attrs[0].span,
-                            &format!("attribute without generic parameters"),
-                        )
-                        .span_label(
-                            attrs[0].span,
-                            "attributes are only permitted when preceding parameters",
-                        )
-                        .emit();
+                        self.struct_span_err(attrs[0].span, "attribute without generic parameters")
+                            .span_label(
+                                attrs[0].span,
+                                "attributes are only permitted when preceding parameters",
+                            )
+                            .emit();
                     }
                 }
                 break;

src/librustc_passes/weak_lang_items.rs

@@ -64,9 +64,9 @@ fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) {
     for (name, &item) in WEAK_ITEMS_REFS.iter() {
         if missing.contains(&item) && !whitelisted(tcx, item) && items.require(item).is_err() {
             if item == lang_items::PanicImplLangItem {
-                tcx.sess.err(&format!("`#[panic_handler]` function required, but not found"));
+                tcx.sess.err("`#[panic_handler]` function required, but not found");
             } else if item == lang_items::OomLangItem {
-                tcx.sess.err(&format!("`#[alloc_error_handler]` function required, but not found"));
+                tcx.sess.err("`#[alloc_error_handler]` function required, but not found");
             } else {
                 tcx.sess.err(&format!("language item required, but not found: `{}`", name));
             }

src/librustc_resolve/diagnostics.rs

@@ -179,7 +179,7 @@ impl<'a> Resolver<'a> {
                 if has_generic_params == HasGenericParams::Yes {
                     // Try to retrieve the span of the function signature and generate a new
                     // message with a local type or const parameter.
-                    let sugg_msg = &format!("try using a local generic parameter instead");
+                    let sugg_msg = "try using a local generic parameter instead";
                     if let Some((sugg_span, snippet)) = sm.generate_local_type_param_snippet(span) {
                         // Suggest the modification to the user
                         err.span_suggestion(
@@ -194,7 +194,7 @@ impl<'a> Resolver<'a> {
                             format!("try adding a local generic parameter in this method instead"),
                         );
                     } else {
-                        err.help(&format!("try using a local generic parameter instead"));
+                        err.help("try using a local generic parameter instead");
                     }
                 }
 

src/librustc_session/config.rs

@@ -1500,10 +1500,8 @@ fn parse_libs(
             {
                 early_error(
                     error_format,
-                    &format!(
-                        "the library kind 'static-nobundle' is only \
-                         accepted on the nightly compiler"
-                    ),
+                    "the library kind 'static-nobundle' is only \
+                     accepted on the nightly compiler",
                 );
             }
             let mut name_parts = name.splitn(2, ':');

src/librustc_typeck/astconv.rs

@@ -888,10 +888,10 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 ),
             );
         }
-        err.note(&format!(
+        err.note(
             "because of the default `Self` reference, type parameters must be \
-                            specified on object types"
-        ));
+                  specified on object types",
+        );
         err.emit();
     }
 

src/librustc_typeck/coherence/inherent_impls.rs

@@ -283,10 +283,10 @@ impl ItemLikeVisitor<'v> for InherentCollect<'tcx> {
                     "no base type found for inherent implementation"
                 )
                 .span_label(ty.span, "impl requires a base type")
-                .note(&format!(
+                .note(
                     "either implement a trait on it or create a newtype \
-                                    to wrap it instead"
-                ))
+                       to wrap it instead",
+                )
                 .emit();
                 return;
             }

src/librustc_typeck/collect.rs

@@ -1282,10 +1282,10 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::Generics {
                             param.hir_id,
                             param.span,
                             |lint| {
-                                lint.build(&format!(
+                                lint.build(
                                     "defaults for type parameters are only allowed in \
-                                        `struct`, `enum`, `type`, or `trait` definitions."
-                                ))
+                                            `struct`, `enum`, `type`, or `trait` definitions.",
+                                )
                                 .emit();
                             },
                         );