Dialyzer notifies an error with typespec for DynamicSupervisor.init/1

[PaoloLaurenti]

The issue explained inside the PR #7596 is still present.
That patch has been released with the 1.6.5 version but I still face the issue with this version.

Environment

• Elixir & Erlang/OTP versions (elixir --version): Elixir 1.6.5 / Erlang 20.3.1
• Operating system: Ubuntu 17.10

Current behavior

With this code

defmodule TestDynamicSup do
  use DynamicSupervisor

  @spec init(arg :: any()) :: {:ok, DynamicSupervisor.sup_flags()} | :ignore
  @impl DynamicSupervisor
  def init(_arg), do: DynamicSupervisor.init(strategy: :one_for_one)

end

dialyzer notifies this error:

Starting Dialyzer
dialyzer args: [
  check_plt: false,
  init_plt: '/home/paolo/dev/priv/learning/elixir/test_dynamic_sup/_build/dev/dialyxir_erlang-20.3.1_elixir-1.6.5_deps-dev.plt',
  files_rec: ['/home/paolo/dev/priv/learning/elixir/test_dynamic_sup/_build/dev/lib/test_dynamic_sup/ebin'],
  warnings: [:unknown]
]
done in 0m0.89s
lib/test_dynamic_sup.ex:4: The specification for 'Elixir.TestDynamicSup':init/1 has an opaque subtype 'Elixir.DynamicSupervisor':sup_flags() which is violated by the success typing (_) -> {'ok',#{'extra_arguments':=_, 'max_children':=_, 'strategy':=_, _=>_}}

Expected behavior

No error from Dialyzer