Implement hashCode for classes with equals().

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java
index d906da89be8ae6da794b54037b9f667497d68f8a..a9026670ff5e7e1166f0ea5470d13431cffaaaba 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/element/PropertyAccessorElementImpl.java
@@ -18,6 +18,7 @@ import com.google.dart.engine.element.ElementKind;
 import com.google.dart.engine.element.ElementVisitor;
 import com.google.dart.engine.element.PropertyAccessorElement;
 import com.google.dart.engine.element.PropertyInducingElement;
+import com.google.dart.engine.utilities.general.ObjectUtilities;
 
 /**
  * Instances of the class {@code PropertyAccessorElementImpl} implement a
@@ -106,6 +107,11 @@ public class PropertyAccessorElementImpl extends ExecutableElementImpl implement
   }
 
   @Override
+  public int hashCode() {
+    return ObjectUtilities.combineHashCodes(super.hashCode(), isGetter() ? 1 : 2);
+  }
+
+  @Override
   public boolean isAbstract() {
     return hasModifier(Modifier.ABSTRACT);
   }