ExitDetector: Do not special case enums, since null exists

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index d5035ee362263b63590c759d013c12d177814893..26d1ed7c7ae351bd8858cdb08965edee5581de5d 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -3807,18 +3807,7 @@ class ExitDetector extends GeneralizingAstVisitor<bool> {
           return false;
         }
       }
-      // All of the members exit, determine whether there are possible cases
-      // that are not caught by the members.
-      DartType type = node.expression?.bestType;
-      if (type is InterfaceType) {
-        ClassElement element = type.element;
-        if (element != null && element.isEnum) {
-          // If some of the enum values are not covered, then a warning will
-          // have already been generated, so there's no point in generating a
-          // hint.
-          return true;
-        }
-      }
+      // As all cases exit, return whether that list includes `default`.
       return hasDefault;
     } finally {
       _enclosingBlockContainsBreak = outerBreakValue;