MVC 3 Can't pass string as a View's model?

I have a strange problem with my model passed to the View

Controller

[Authorize]
public ActionResult Sth()
{
    return View("~/Views/Sth/Sth.cshtml", "abc");
}

View

@model string

@{
    ViewBag.Title = "lorem";
    Layout = "~/Views/Shared/Default.cshtml";
}

The error message

The view '~/Views/Sth/Sth.cshtml' or its master was not found or no view engine supports the searched locations. The following locations were searched:
~/Views/Sth/Sth.cshtml
~/Views/Sth/abc.master  //string model is threated as a possible Layout's name ?
~/Views/Shared/abc.master
~/Views/Sth/abc.cshtml
~/Views/Sth/abc.vbhtml
~/Views/Shared/abc.cshtml
~/Views/Shared/abc.vbhtml

Why can't I pass a simple string as a model ?

Yes you can if you are using the right overload:

return View("~/Views/Sth/Sth.cshtml" /* view name*/, 
            null /* master name */,  
            "abc" /* model */);

If you use named parameters you can skip the need to give the first parameter altogether

return View(model:"abc");

or

return View(viewName:"~/Views/Sth/Sth.cshtml", model:"abc");

will also serve the purpose.

You meant this View overload:

protected internal ViewResult View(string viewName, Object model)

MVC is confused by this overload:

protected internal ViewResult View(string viewName, string masterName)

Use this overload:

protected internal virtual ViewResult View(string viewName, string masterName,
                                           Object model)

This way:

return View("~/Views/Sth/Sth.cshtml", null , "abc");

By the way, you could just use this:

return View("Sth", null, "abc");

Overload resolution on MSDN

It also works if you pass null for the first two parameters:

return View(null, null, "abc");

It also works if you declare the string as an object:

object str = "abc";
return View(str);

Or:

return View("abc" as object);