Elixir 1.5 supervisor problem :simple_one_for_one

test.ex

defmodule Sup do
  use Supervisor

  def start_link, do: Supervisor.start_link(__MODULE__, [], name: __MODULE__)

  def init(_) do
    agent_spec = Supervisor.child_spec(Child, start: {Child, :start_link, []})
    Supervisor.init([agent_spec], strategy: :simple_one_for_one)
  end

  def add_item(name), do: Supervisor.start_child(__MODULE__, [name])
end

defmodule Child do
  use GenServer

  def start_link(_opts, name), do: GenServer.start_link(__MODULE__, [], name: name)

  def init(_), do: {:ok, []}
end

{:error,
{:EXIT,
{:undef,
[{Child, :start_link, ["abc"], []},
{:supervisor, :do_start_child_i, 3, [file: 'supervisor.erl', line: 381]},
{:supervisor, :handle_call, 3, [file: 'supervisor.erl', line: 406]},
{:gen_server, :try_handle_call, 4, [file: 'gen_server.erl', line: 636]},
{:gen_server, :handle_msg, 6, [file: 'gen_server.erl', line: 665]},
{:proc_lib, :init_p_do_apply, 3, [file: 'proc_lib.erl', line: 247]}]}}}