class RuboCop::Cop::Rails::AttributeDefaultBlockValue

def on_send(node)
  default_attribute(node) do |attribute|
    value = attribute.children.last
    return unless TYPE_OFFENDERS.any?(value.type)
    add_offense(value) do |corrector|
      expression = default_attribute(node).children.last
      corrector.replace(value, "-> { #{expression.source} }")
    end
  end
end