title: Method cannot be declared public because its parameter uses an internal type
body: <p>I have an auto-generated accessors for an Entity:</p>
  
  <pre><code>//auto-generated code:
  extension Entity1{
    @objc(addEntity1toEntity2Object:)
    @NSManaged public func addEntity1toEntity2Object(_ value: Entity2)
    ...
  }
  </code></pre>
  
  <p>and I get a build Error:</p>
  
  <blockquote>
    <p>Method cannot be declared public because its parameter uses an internal type</p>
  </blockquote>