fix clippy::{redundant_guards, useless_format}

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -245,7 +245,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             let Trait(PolyTraitRef { trait_ref, span: trait_span, .. }, _) = bound else { return; };
             diag.span_note(
                 *trait_span,
-                format!("due to current limitations in the borrow checker, this implies a `'static` lifetime")
+                "due to current limitations in the borrow checker, this implies a `'static` lifetime"
             );
             let Some(generics_fn) = hir.get_generics(self.body.source.def_id().expect_local()) else { return; };
             let Def(_, trait_res_defid) = trait_ref.path.res else { return; };
@@ -277,7 +277,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         if suggestions.len() > 0 {
             suggestions.dedup();
             diag.multipart_suggestion_verbose(
-                format!("consider restricting the type parameter to the `'static` lifetime"),
+                "consider restricting the type parameter to the `'static` lifetime",
                 suggestions,
                 Applicability::MaybeIncorrect,
             );

compiler/rustc_codegen_ssa/src/base.rs

@@ -181,7 +181,7 @@ pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
                 old_info
             }
         }
-        (_, &ty::Dynamic(ref data, _, _)) => meth::get_vtable(cx, source, data.principal()),
+        (_, ty::Dynamic(data, _, _)) => meth::get_vtable(cx, source, data.principal()),
         _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target),
     }
 }

compiler/rustc_hir_typeck/src/demand.rs

@@ -644,7 +644,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             if self.can_eq(self.param_env, ty, expected) {
                                 err.span_label(
                                     ex.span,
-                                    format!("expected because of this `break`"),
+                                    "expected because of this `break`",
                                 );
                                 exit = true;
                             }

compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs

@@ -621,7 +621,7 @@ fn foo(&self) -> Self::T { String::new() }
                         {
                             diag.span_label(
                                 item.span,
-                                format!("associated type is `default` and may be overridden"),
+                                "associated type is `default` and may be overridden",
                             );
                             return true;
                         }

compiler/rustc_middle/src/mir/pretty.rs

@@ -1146,10 +1146,10 @@ fn post_fmt_projection(projection: &[PlaceElem<'_>], fmt: &mut Formatter<'_>) ->
             ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
                 write!(fmt, "[-{offset:?} of {min_length:?}]")?;
             }
-            ProjectionElem::Subslice { from, to, from_end: true } if to == 0 => {
+            ProjectionElem::Subslice { from, to: 0, from_end: true } => {
                 write!(fmt, "[{from:?}:]")?;
             }
-            ProjectionElem::Subslice { from, to, from_end: true } if from == 0 => {
+            ProjectionElem::Subslice { from: 0, to, from_end: true } => {
                 write!(fmt, "[:-{to:?}]")?;
             }
             ProjectionElem::Subslice { from, to, from_end: true } => {

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -740,9 +740,7 @@ fn non_exhaustive_match<'p, 'tcx>(
                         ));
                 }
             } else if ty == cx.tcx.types.str_ {
-                err.note(format!(
-                    "`&str` cannot be matched exhaustively, so a wildcard `_` is necessary",
-                ));
+                err.note("`&str` cannot be matched exhaustively, so a wildcard `_` is necessary");
             } else if cx.is_foreign_non_exhaustive_enum(ty) {
                 err.note(format!("`{ty}` is marked as non-exhaustive, so a wildcard `_` is necessary to match exhaustively"));
             }

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -763,7 +763,7 @@ pub(super) fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span>
         // and `_1` is the `Place` for `somenum`.
         //
         // If and when the Issue is resolved, remove this special case match pattern:
-        StatementKind::FakeRead(box (cause, _)) if cause == FakeReadCause::ForGuardBinding => None,
+        StatementKind::FakeRead(box (FakeReadCause::ForGuardBinding, _)) => None,
 
         // Retain spans from all other statements
         StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding`

compiler/rustc_mir_transform/src/large_enums.rs

@@ -54,11 +54,8 @@ impl EnumSizeOpt {
         let layout = tcx.layout_of(param_env.and(ty)).ok()?;
         let variants = match &layout.variants {
             Variants::Single { .. } => return None,
-            Variants::Multiple { tag_encoding, .. }
-                if matches!(tag_encoding, TagEncoding::Niche { .. }) =>
-            {
-                return None;
-            }
+            Variants::Multiple { tag_encoding: TagEncoding::Niche { .. }, .. } => return None,
+
             Variants::Multiple { variants, .. } if variants.len() <= 1 => return None,
             Variants::Multiple { variants, .. } => variants,
         };

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -186,7 +186,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                 fallback_label: format!("not a {expected}"),
                 span,
                 span_label: match res {
-                    Res::Def(kind, def_id) if kind == DefKind::TyParam => {
+                    Res::Def(DefKind::TyParam, def_id) => {
                         Some((self.r.def_span(def_id), "found this type parameter"))
                     }
                     _ => None,

compiler/rustc_span/src/lib.rs

@@ -1753,7 +1753,7 @@ impl SourceFile {
         // is recorded.
         let diff = match self.normalized_pos.binary_search_by(|np| np.pos.cmp(&pos)) {
             Ok(i) => self.normalized_pos[i].diff,
-            Err(i) if i == 0 => 0,
+            Err(0) => 0,
             Err(i) => self.normalized_pos[i - 1].diff,
         };
 
@@ -1775,7 +1775,7 @@ impl SourceFile {
             .binary_search_by(|np| (np.pos.0 + np.diff).cmp(&(self.start_pos.0 + offset)))
         {
             Ok(i) => self.normalized_pos[i].diff,
-            Err(i) if i == 0 => 0,
+            Err(0) => 0,
             Err(i) => self.normalized_pos[i - 1].diff,
         };
 

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

@@ -3211,7 +3211,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         let name = match self.tcx.opaque_type_origin(def_id.expect_local()) {
             hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) => {
-                format!("opaque type")
+                "opaque type".to_string()
             }
             hir::OpaqueTyOrigin::TyAlias { .. } => {
                 format!("`{}`", self.tcx.def_path_debug_str(def_id))

src/librustdoc/doctest.rs

@@ -681,7 +681,7 @@ pub(crate) fn make_test(
             if s.contains(crate_name) {
                 // rustdoc implicitly inserts an `extern crate` item for the own crate
                 // which may be unused, so we need to allow the lint.
-                prog.push_str(&format!("#[allow(unused_extern_crates)]\n"));
+                prog.push_str("#[allow(unused_extern_crates)]\n");
 
                 prog.push_str(&format!("extern crate r#{crate_name};\n"));
                 line_offset += 1;