use matches!() macro for simple if let conditions

compiler/rustc_ast/src/ast.rs

@@ -1931,7 +1931,7 @@ pub enum TyKind {
 
 impl TyKind {
     pub fn is_implicit_self(&self) -> bool {
-        if let TyKind::ImplicitSelf = *self { true } else { false }
+        matches!(self, TyKind::ImplicitSelf)
     }
 
     pub fn is_unit(&self) -> bool {
@@ -2227,7 +2227,7 @@ pub enum Async {
 
 impl Async {
     pub fn is_async(self) -> bool {
-        if let Async::Yes { .. } = self { true } else { false }
+        matches!(self, Async::Yes { .. })
     }
 
     /// In this case this is an `async` return, the `NodeId` for the generated `impl Trait` item.
@@ -2508,7 +2508,7 @@ pub enum VisibilityKind {
 
 impl VisibilityKind {
     pub fn is_pub(&self) -> bool {
-        if let VisibilityKind::Public = *self { true } else { false }
+        matches!(self, VisibilityKind::Public)
     }
 }
 

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -868,10 +868,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     .emit();
                 }
 
-                if !bounds
-                    .iter()
-                    .any(|b| if let GenericBound::Trait(..) = *b { true } else { false })
-                {
+                if !bounds.iter().any(|b| matches!(b, GenericBound::Trait(..))) {
                     self.err_handler().span_err(ty.span, "at least one trait must be specified");
                 }
 

compiler/rustc_attr/src/builtin.rs

@@ -160,10 +160,10 @@ pub enum StabilityLevel {
 
 impl StabilityLevel {
     pub fn is_unstable(&self) -> bool {
-        if let StabilityLevel::Unstable { .. } = *self { true } else { false }
+        matches!(self, StabilityLevel::Unstable { .. })
     }
     pub fn is_stable(&self) -> bool {
-        if let StabilityLevel::Stable { .. } = *self { true } else { false }
+        matches!(self, StabilityLevel::Stable { .. })
     }
 }
 

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -1529,7 +1529,7 @@ impl<'a> TraitDef<'a> {
             }
         }
 
-        let is_tuple = if let ast::VariantData::Tuple(..) = struct_def { true } else { false };
+        let is_tuple = matches!(struct_def, ast::VariantData::Tuple(..));
         match (just_spans.is_empty(), named_idents.is_empty()) {
             (false, false) => cx.span_bug(
                 self.span,

compiler/rustc_errors/src/snippet.rs

@@ -118,17 +118,15 @@ pub struct Annotation {
 impl Annotation {
     /// Whether this annotation is a vertical line placeholder.
     pub fn is_line(&self) -> bool {
-        if let AnnotationType::MultilineLine(_) = self.annotation_type { true } else { false }
+        matches!(self.annotation_type, AnnotationType::MultilineLine(_))
     }
 
     pub fn is_multiline(&self) -> bool {
-        match self.annotation_type {
+        matches!(self.annotation_type,
             AnnotationType::Multiline(_)
             | AnnotationType::MultilineStart(_)
             | AnnotationType::MultilineLine(_)
-            | AnnotationType::MultilineEnd(_) => true,
-            _ => false,
-        }
+            | AnnotationType::MultilineEnd(_))
     }
 
     pub fn len(&self) -> usize {

compiler/rustc_lint/src/builtin.rs

@@ -1985,9 +1985,9 @@ impl ExplicitOutlivesRequirements {
             .filter_map(|(i, bound)| {
                 if let hir::GenericBound::Outlives(lifetime) = bound {
                     let is_inferred = match tcx.named_region(lifetime.hir_id) {
-                        Some(Region::Static) if infer_static => inferred_outlives
-                            .iter()
-                            .any(|r| if let ty::ReStatic = r { true } else { false }),
+                        Some(Region::Static) if infer_static => {
+                            inferred_outlives.iter().any(|r| matches!(r, ty::ReStatic))
+                        }
                         Some(Region::EarlyBound(index, ..)) => inferred_outlives.iter().any(|r| {
                             if let ty::ReEarlyBound(ebr) = r { ebr.index == index } else { false }
                         }),
@@ -2079,9 +2079,10 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
             let mut lint_spans = Vec::new();
 
             for param in hir_generics.params {
-                let has_lifetime_bounds = param.bounds.iter().any(|bound| {
-                    if let hir::GenericBound::Outlives(_) = bound { true } else { false }
-                });
+                let has_lifetime_bounds = param
+                    .bounds
+                    .iter()
+                    .any(|bound| matches!(bound, hir::GenericBound::Outlives(_)));
                 if !has_lifetime_bounds {
                     continue;
                 }

compiler/rustc_middle/src/middle/cstore.rs

@@ -69,7 +69,7 @@ pub enum LibSource {
 
 impl LibSource {
     pub fn is_some(&self) -> bool {
-        if let LibSource::Some(_) = *self { true } else { false }
+        matches!(self, LibSource::Some(_))
     }
 
     pub fn option(&self) -> Option<PathBuf> {

compiler/rustc_mir/src/borrow_check/diagnostics/outlives_suggestion.rs

@@ -115,9 +115,10 @@ impl OutlivesSuggestionBuilder {
             //    should just replace 'a with 'static.
             // 3) Suggest unifying 'a with 'b if we have both 'a: 'b and 'b: 'a
 
-            if outlived.iter().any(|(_, outlived_name)| {
-                if let RegionNameSource::Static = outlived_name.source { true } else { false }
-            }) {
+            if outlived
+                .iter()
+                .any(|(_, outlived_name)| matches!(outlived_name.source, RegionNameSource::Static))
+            {
                 suggested.push(SuggestedConstraint::Static(fr_name));
             } else {
                 // We want to isolate out all lifetimes that should be unified and print out

compiler/rustc_mir/src/transform/promote_consts.rs

@@ -92,7 +92,7 @@ pub enum TempState {
 impl TempState {
     pub fn is_promotable(&self) -> bool {
         debug!("is_promotable: self={:?}", self);
-        if let TempState::Defined { .. } = *self { true } else { false }
+        matches!(self, TempState::Defined { .. } )
     }
 }
 

compiler/rustc_mir/src/transform/simplify.rs

@@ -281,8 +281,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
 
     fn strip_nops(&mut self) {
         for blk in self.basic_blocks.iter_mut() {
-            blk.statements
-                .retain(|stmt| if let StatementKind::Nop = stmt.kind { false } else { true })
+            blk.statements.retain(|stmt| !matches!(stmt.kind, StatementKind::Nop))
         }
     }
 }

compiler/rustc_mir_build/src/build/block.rs

@@ -96,8 +96,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     );
                 }
                 StmtKind::Let { remainder_scope, init_scope, pattern, initializer, lint_level } => {
-                    let ignores_expr_result =
-                        if let PatKind::Wild = *pattern.kind { true } else { false };
+                    let ignores_expr_result = matches!(*pattern.kind, PatKind::Wild);
                     this.block_context.push(BlockFrame::Statement { ignores_expr_result });
 
                     // Enter the remainder scope, i.e., the bindings' destruction scope.

compiler/rustc_mir_build/src/build/matches/mod.rs

@@ -1793,7 +1793,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     .flat_map(|(bindings, _)| bindings)
                     .chain(&candidate.bindings)
                     .filter(|binding| {
-                        if let BindingMode::ByValue = binding.binding_mode { true } else { false }
+                        matches!(binding.binding_mode, BindingMode::ByValue )
                     });
             // Read all of the by reference bindings to ensure that the
             // place they refer to can't be modified by the guard.

compiler/rustc_resolve/src/build_reduced_graph.rs

@@ -395,7 +395,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
         // so prefixes are prepended with crate root segment if necessary.
         // The root is prepended lazily, when the first non-empty prefix or terminating glob
         // appears, so imports in braced groups can have roots prepended independently.
-        let is_glob = if let ast::UseTreeKind::Glob = use_tree.kind { true } else { false };
+        let is_glob = matches!(use_tree.kind, ast::UseTreeKind::Glob);
         let crate_root = match prefix_iter.peek() {
             Some(seg) if !seg.ident.is_path_segment_keyword() && seg.ident.span.rust_2015() => {
                 Some(seg.ident.span.ctxt())

compiler/rustc_resolve/src/late.rs

@@ -1034,7 +1034,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             let mut add_bindings_for_ns = |ns| {
                 let parent_rib = self.ribs[ns]
                     .iter()
-                    .rfind(|r| if let ItemRibKind(_) = r.kind { true } else { false })
+                    .rfind(|r| matches!(r.kind, ItemRibKind(_)))
                     .expect("associated item outside of an item");
                 seen_bindings
                     .extend(parent_rib.bindings.iter().map(|(ident, _)| (*ident, ident.span)));

compiler/rustc_typeck/src/check/expr.rs

@@ -439,9 +439,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // This is maybe too permissive, since it allows
             // `let u = &raw const Box::new((1,)).0`, which creates an
             // immediately dangling raw pointer.
-            self.typeck_results.borrow().adjustments().get(base.hir_id).map_or(false, |x| {
-                x.iter().any(|adj| if let Adjust::Deref(_) = adj.kind { true } else { false })
-            })
+            self.typeck_results
+                .borrow()
+                .adjustments()
+                .get(base.hir_id)
+                .map_or(false, |x| x.iter().any(|adj| matches!(adj.kind, Adjust::Deref(_))))
         });
         if !is_named {
             self.tcx.sess.emit_err(AddressOfTemporaryTaken { span: oprnd.span })