Update instead of override classHasLombokAnnotation flag

Fixes issues where inner classes would override this flag.

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/AbstractLombokAwareRule.java

@@ -65,21 +65,27 @@ public class AbstractLombokAwareRule extends AbstractIgnoredAnnotationRule {
 
     @Override
     public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
+        boolean oldValue = classHasLombokAnnotation;
         classHasLombokAnnotation = hasLombokAnnotation(node);
-        return super.visit(node, data);
+        Object result = super.visit(node, data);
+        classHasLombokAnnotation = oldValue;
+        return result;
     }
 
     @Override
     public Object visit(ASTEnumDeclaration node, Object data) {
+        boolean oldValue = classHasLombokAnnotation;
         classHasLombokAnnotation = hasLombokAnnotation(node);
-        return super.visit(node, data);
+        Object result = super.visit(node, data);
+        classHasLombokAnnotation = oldValue;
+        return result;
     }
 
     /**
      * Returns whether there have been class level Lombok annotations found.
      * Note: this can only be queried after the class declaration node has been
      * processed.
-     * 
+     *
      * @return <code>true</code> if a lombok annotation at the class level has
      *         been found
      */

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/design/ImmutableFieldRule.java

@@ -55,7 +55,7 @@ public class ImmutableFieldRule extends AbstractLombokAwareRule {
             AccessNode accessNodeParent = field.getAccessNodeParent();
             if (accessNodeParent.isStatic() || !accessNodeParent.isPrivate() || accessNodeParent.isFinal()
                     || accessNodeParent.isVolatile()
-                    || hasClassLombokAnnotation()
+                    || hasLombokAnnotation(node)
                     || hasIgnoredAnnotation((Annotatable) accessNodeParent)) {
                 continue;
             }

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/design/xml/SingularField.xml

@@ -573,6 +573,47 @@ public class MyClass {
         ]]></code>
     </test-code>
 
+    <test-code>
+        <description>[java] SingularField: Lombok false positive with inner class and annotated outer class</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+import lombok.Data;
+
+@Data
+public class Outer {
+    public class Inner {
+        private String innerField;
+    }
+
+    private String outerField;
+
+    public Outer(String outerField) {
+        this.outerField = outerField;
+    }
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>[java] SingularField: Lombok false positive with annotated inner class</description>
+        <expected-problems>1</expected-problems>
+        <code><![CDATA[
+import lombok.Data;
+
+public class Outer {
+    @Data
+    public class Inner {
+        private String innerField;
+    }
+
+    private String outerField;
+
+    public Outer(String outerField) {
+        this.outerField = outerField;
+    }
+}
+        ]]></code>
+    </test-code>
 
     <test-code>
         <description>#177 [java] SingularField with lambdas as final fields</description>