* @param listener - the listener to invoke in that case.
*/
@SuppressWarnings("unchecked")
public <TKey> void addListener(final StructureModifier<TKey> uncompiled, final CompileListener<TKey> listener) {
synchronized (listenerLock) {
StructureKey key = new StructureKey(uncompiled);
@SuppressWarnings("rawtypes")
List list = listeners.get(key);
if (list != null) {