module ActiveRecord::Scoping::Default::ClassMethods

scope which references a scope...
situation where a default scope references a scope which has a default
The ignore_default_scope flag is used to prevent an infinite recursion

def evaluate_default_scope
  return if ignore_default_scope?
  begin
    self.ignore_default_scope = true
    yield
  ensure
    self.ignore_default_scope = false
  end
end