Spinal can't clone class
========================

Introduction
------------

This error happens when SpinalHDL wants to create a new datatype instance via the ``cloneOf`` function but isn't able to do it.
The reason for this is nearly always because it can't retrieve the construction parameters of a ``Bundle``.

Example
-------

The following code:

.. code-block:: scala

    // cloneOf(this) isn't able to retrieve the width value that was used to construct itself
    class RGB(width : Int) extends Bundle {
      val r, g, b = UInt(width bits)
    }

    class TopLevel extends Component {
      val tmp = Stream(new RGB(8)) // Stream requires the capability to cloneOf(new RGB(8))
    }

will throw:

.. code-block:: text

   *** Spinal can't clone class spinal.tester.PlayDevMessages$RGB datatype
   *** You have two way to solve that :
   *** In place to declare a "class Bundle(args){}", create a "case class Bundle(args){}"
   *** Or override by your self the bundle clone function
     ***
     Source file location of the RGB class definition via the stack trace
     ***

A fix could be:

.. code-block:: scala

   case class RGB(width : Int) extends Bundle {
     val r, g, b = UInt(width bits)
   }

   class TopLevel extends Component {
     val tmp = Stream(RGB(8))
   }