Issue Description:

When declaring a function as a constant/variable, auto-complete breaks in many cases. Declaring as a top level function, or as a property in a class/struct also appear to be broken. (though in a Playground, the top level function case does work fine).

let foo: (Int) -> Void = { num in
// num appears as <<error type>>
}

The same `<<error type>>` shows up when declaring that same constant in a class or struct.

Declaring the function as an enum computed property actually works.

enum TestFoo {

var foo: (Int) -\> Void { return { num in

    // num properly completes with type Int

    }

}

}

Another way to get auto-complete working is to wrap it in an outer function:

func wrapFoo {
let foo: (Int) -> Void = { num in
// num properly completes with type Int
}
}

Specifying the type in the closure itself also gets auto-complete working:

let foo = { (num: Int) -> Void in
// num is Int
}

My understanding of Swift is that functions are normal first class types and so should be legal as any struct or class property, or as a top level constant. More over, these examples all compile fine, but fail to auto-complete properly, all with <<error type>>.