Issue 5055. Visit field getter/setter only once.

compiler/java/com/google/dart/compiler/resolver/Resolver.java

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 package com.google.dart.compiler.resolver;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.dart.compiler.DartCompilationPhase;
@@ skipping 174 matching lines @@
     private EnclosingElement currentHolder;
     private EnclosingElement enclosingElement;
     private MethodElement currentMethod;
     private boolean inInstanceVariableInitializer;
     private boolean inInitializer;
     private MethodElement innermostFunction;
     private ResolutionContext context;
     private Set<LabelElement> referencedLabels = Sets.newHashSet();
     private Set<LabelElement> labelsInScopes = Sets.newHashSet();
     private Set<FieldElement> finalsNeedingInitializing = Sets.newHashSet();
+    private Set<FieldElement> resolvedFields = Sets.newHashSet();
 
     @VisibleForTesting
     public ResolveElementsVisitor(ResolutionContext context,
                                   EnclosingElement currentHolder,
                                   MethodElement currentMethod) {
       super(typeProvider);
       this.context = context;
       this.currentMethod = currentMethod;
       this.innermostFunction = currentMethod;
       this.currentHolder = currentHolder;
@@ skipping 523 matching lines @@
         } else if (isTopLevel) {
           onError(node, ResolverErrorCode.TOPLEVEL_FINAL_REQUIRES_VALUE);
         } else {
           // If a final instance field wasn't initialized at declaration, we must check
           // at construction time.
           this.finalsNeedingInitializing.add(node.getElement());
         }
       }
 
       // If field is an accessor, both getter and setter need to be visited (if present).
+      // We check for duplicates because top-level fields are visited twice - for each accessor.
       FieldNodeElement field = node.getElement();
-      if (field.getGetter() != null) {
-        resolve(field.getGetter().getNode());
-      }
-      if (field.getSetter() != null) {
-        resolve(field.getSetter().getNode());
+      if (!resolvedFields.contains(field)) {
+        resolvedFields.add(field);
+        if (field.getGetter() != null) {
+          resolve(field.getGetter().getNode());
+        }
+        if (field.getSetter() != null) {
+          resolve(field.getSetter().getNode());
+        }
       }
       return null;
     }
 
     @Override
     public Element visitFieldDefinition(DartFieldDefinition node) {
       node.getMetadata().accept(this);
       visit(node.getFields());
       return null;
     }
@@ skipping 1550 matching lines @@
           ClassElement currentClass = (ClassElement) constructor.getEnclosingElement();
           if (nextClass == currentClass) {
             return (ConstructorNodeElement) nextConstructorElement;
           }
         }
       }
     }
     return null;
   }
 }