   @doc false
   defmacro __using__(_opts) do
     quote do
-      Enum.each(Mix.Task.supported_attributes(),
-        &Module.register_attribute(__MODULE__, &1, persist: true))
+      Enum.each(
+        Mix.Task.supported_attributes(),
+        &Module.register_attribute(__MODULE__, &1, persist: true)
+      )
+
       @behaviour Mix.Task.Compiler
     end
   end

  @callback run([binary]) ::
              :ok
              | :noop
              | {:ok | :noop | :error, [Diagnostic.t]}

  @doc """
  Lists manifest files for the compiler.
  """
  @callback manifests() :: [Path.t]

  @doc """
  Removes build artifacts and manifests.

    case result do
      {status, diagnostics} when status in [:ok, :noop, :error] and is_list(diagnostics) ->
        {status, diagnostics}

      _ when result in [:ok, :noop] ->
        {result, []}

      _ ->
        Mix.shell().error(
          "[warning] Mix compiler #{inspect(name)} was supposed to return " <>
            ":ok | :noop | {:ok | :noop | :error, [diagnostic]} but it " <>
            "returned #{inspect(result)}"
        )

        {:noop, []}
    end
  end
