code: public JvmIdentifiableElement getVisibleType(JvmMember context, String name) {
  		if (context == null)
  			return null;
  		Map<String, JvmIdentifiableElement> map = visibleElements.get(context);
  		if (map == null) {
  			map = create(context);
  		}
  		return map.get(name);
  	}
docs: Returns a type with the given name that is reachable in the context.
  If the context is <code>null</code>, it is assumed that no type is visible.
  @return the visible type or <code>null</code>