value-processor/src/org/immutables/value/processor/meta/AttributeBuilderReflection.java
private static String cachingKey(ValueAttribute valueAttribute) {
    return String.format("%s-%s",
        valueAttribute.containedTypeElement.getQualifiedName(),
        Joiner.on(".").join(valueAttribute.containingType.constitution.style().attributeBuilder()));
  }
private static String cachingKey(ValueAttribute valueAttribute) {
    return String.format("%s-%s",
        valueAttribute.containedTypeElement.getQualifiedName(),
        Joiner.on(".").join(valueAttribute.containingType.constitution.style().attributeBuilder()));
  }
The same class included in two parents, may or may not be nested builders based on that discovery pattern