Use if let for everything

Author: tiif

compiler/rustc_next_trait_solver/src/solve/mod.rs

@@ -155,14 +155,12 @@ where
     ) -> QueryResult<I> {
         // Iterate through all goals in param_env to find the one that has the same symbol.
         for pred in param_env.caller_bounds().iter() {
-            match pred.kind().skip_binder() {
-                ty::ClauseKind::UnstableFeature(sym) => {
-                    if sym == symbol {
-                        return self
-                            .evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
-                    }
+            if let ty::ClauseKind::UnstableFeature(sym) = pred.kind().skip_binder() {
+                if sym == symbol {
+                    return self
+                        .evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
                 }
-                _ => {} // don't care
+
             }
         }
 

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -767,13 +767,10 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 ty::PredicateKind::Clause(ty::ClauseKind::UnstableFeature(symbol)) => {
                     // Iterate through all goals in param_env to find the one that has the same symbol.
                     for pred in obligation.param_env.caller_bounds().iter() {
-                        match pred.kind().skip_binder() {
-                            ty::ClauseKind::UnstableFeature(sym) => {
-                                if sym == symbol {
-                                    return ProcessResult::Changed(Default::default());
-                                }
+                        if let ty::ClauseKind::UnstableFeature(sym) =  pred.kind().skip_binder() {
+                            if sym == symbol {
+                                return ProcessResult::Changed(Default::default());
                             }
-                            _ => {} // don't care
                         }
                     }
                     // Check if feature is enabled at crate level with #[feature(..)] or if we are currently in codegen.

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

@@ -840,13 +840,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
                 ty::PredicateKind::Clause(ty::ClauseKind::UnstableFeature(symbol)) => {
                     for pred in obligation.param_env.caller_bounds().iter() {
-                        match pred.kind().skip_binder() {
-                            ty::ClauseKind::UnstableFeature(sym) => {
-                                if sym == symbol {
-                                    return Ok(EvaluatedToOk);
-                                }
+                        if let ty::ClauseKind::UnstableFeature(sym) = pred.kind().skip_binder() {
+                            if sym == symbol {
+                                return Ok(EvaluatedToOk);
                             }
-                            _ => {} // don't care
                         }
                     }
                     // Check if feature is enabled at crate level with #[feature(..)] or if we are currently in codegen.