Xcode-beta 8. Can't create core data
<p>I have been trying to add core data.
And every time I got the same error: </p>

<pre><code>error: filename "EntityName +CoreDataClass.swift" used twice: '/Users/userName/Desktop/Development/MyApp/AppName/EntityName +CoreDataClass.swift' and '/Users/userName/Library/Developer/Xcode/DerivedData/AppName-dgwzrmxsetzvtedibxrazuutjwnh/Build/Intermediates/AppName.build/Debug-iphoneos/AppName.build/DerivedSources/CoreDataGenerated/Model/EntityName +CoreDataClass.swift'
</code></pre>

<p>I add core data using the following steps:<br>
1.New file/ DataModel; save it in the root dir of my project<br>
select Model.xcdatamodeld and add entity, add several attributes, save,
editor/create NSManagedObjectClass Subclass.</p>

<p>As a result I observe 4 new files in navigator:
Model.xcdatamodeld, EntityName+CoreDataProperties.swift, EntityName +CoreDataClass.swift, <strong>_COREDATA_DATAMODELNAME_</strong>+CoreDataModel.swift</p>

<p>their content:
<strong>_COREDATA_DATAMODELNAME_</strong>+CoreDataModel.swift:  </p>

<pre><code>import Foundation
import CoreData

___COREDATA_DATAMODEL_MANAGEDOBJECTCLASSES_IMPLEMENTATIONS___
</code></pre>

<p>EntityName +CoreDataClass.swift:  </p>

<pre><code>import Foundation
import CoreData


class EntityName: NSManagedObject {

}
</code></pre>

<p>EntityName+CoreDataProperties.swift:  </p>

<pre><code>import Foundation
import CoreData

extension EntityName {

    @nonobjc class func fetchRequest() -&gt; NSFetchRequest&lt; EntityName &gt; {
        return NSFetchRequest&lt; EntityName &gt;(entityName: "EntityName");
    }

    @NSManaged var str: String?

}
</code></pre>

<p>What I have tried:<br>
1. Clean build, remove DerivedData, delete content of var/folders, restart<br>
2. Delete generated files, displayed in navigator</p>

<p>All my efforts were out of luck.<br>
What I am doing wrong?</p>