new

# File activerecord/lib/active_record/associations.rb, line 125
    def initialize(owner_class_name = nil, reflection = nil, source_reflection = nil)
      if owner_class_name && reflection && source_reflection
        super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
      else
        super("Cannot have a has_many :through association.")
      end
    end