t5578.scala:33: error: type mismatch;
 found   : NumericOpsExp.this.Plus[T]
 required: NumericOpsExp.this.Rep[T]
    (which expands to)  NumericOpsExp.this.Exp[T]
  def plus[T: Numeric](x: Rep[T], y: Rep[T]): Rep[T] = Plus[T](x,y)
                                                              ^
one error found