improve compatibility

src/main/java/spoon/reflect/visitor/CtScanner.java

@@ -143,6 +143,9 @@ public void scan(CtRole role, Collection<? extends CtElement> elements) {
 		}
 	}
 
+	/**
+	 * Generically scans a collection of meta-model elements.
+	 */
 	public void scan(Collection<? extends CtElement> elements) {
 		scan(null, elements);
 	}
@@ -151,15 +154,18 @@ public void scan(Collection<? extends CtElement> elements) {
 	 * Generically scans a meta-model element.
 	 */
 	public void scan(CtRole role, CtElement element) {
-		scan(element);
-	}
-
-	public void scan(CtElement element) {
 		if (element != null) {
 			element.accept(this);
 		}
 	}
 
+	/**
+	 * Generically scans a meta-model element.
+	 */
+	public void scan(CtElement element) {
+		scan(null, element);
+	}
+
 	public <A extends Annotation> void visitCtAnnotation(final CtAnnotation<A> annotation) {
 		enter(annotation);
 		scan(CtRole.TYPE, annotation.getType());
@@ -170,6 +176,9 @@ public <A extends Annotation> void visitCtAnnotation(final CtAnnotation<A> annot
 		exit(annotation);
 	}
 
+	public void scan(Object o) {
+		scan(null, o);
+	}
 	/**
 	 * Generically scans an object that can be an element, a reference, or a
 	 * collection of those.