Rails, as_json, undefined method `serializable_hash'

as_json was failing in one of my Rails models with:

NoMethodError: undefined method `serializable_hash' for ["id", 3]:Array

Eventually figured out that the problem was that I had specified a non-existent association to :include in as_json:


  def as_json(options={})
    super(:include => [:non_existent_association])
  end