Getting 404 with Asynchronous Action (Task <ActionResult>)

Question

Very simple, I converted some synchronous login actions to asynchronous and now they are not found, getting 404.

    public async Task<ActionResult> BetaLoginAsync()
    {            
        return View();
    }

    [HttpPost]
    public async Task<ActionResult> BetaLoginAsync(Models.Authentication.SimpleLoginModel loginModel, string returnUrl)
    {
        if (this.ModelState.IsValid)
        {
            if (await this.ValidateCredentialsAsync(loginModel))
            {
    ...

I thought I did everything I needed, I followed this:

http://www.asp.net/mvc/tutorials/mvc-4/using-asynchronous-methods-in-aspnet-mvc-4

The compiler warns me that the first action method, which only returns the view, does not use the keyword await, so it will work synchronously.

The problem is that when I delete the keyword async, it does not compile at all. The compiler says that the type ViewResultreturned from the call Viewcannot be implicitly converted to a type Task<ActionResult>.

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However, BetaLoginAsync()in order. No asynchronous operation. This is a false positive case of this warning.

You can use return Task.FromResult(View());if you want. It does not matter.