Trivial Enums not marshaling correctly in protocols

[stephen-hawley]

Here's a test:

		[Test]
		public void MakeABear () {
		var swiftCode = @"
public enum Size {
    case small, medium, large
    internal func toString () -> String {
        switch self {
        case .small: return ""small""
        case .medium: return ""medium""
        case .large: return ""large""
	}
    }
}

public protocol Bearlike {
	var name:String { get }
	func speak ()
    var size: Size { get }
}

public func describeBear (b: Bearlike)
{
	print (""I am a bear \(b.toString()) named \(b.name)."")
    b.speak ()
}
";
			var altClass = new CSClass (CSVisibility.Public, "FuzzyWuzzy");
			altClass.Inheritance.Add (new CSIdentifier ("IBearlike"));
			var roar = CSFunctionCall.ConsoleWriteLine (CSConstant.Val ("RAwwr!"));
			var speakBody = CSCodeBlock.Create (roar);
			var speak = new CSMethod (CSVisibility.Public, CSMethodKind.None, CSSimpleType.Void, new CSIdentifier ("Speak"), new CSParameterList (), speakBody);
			altClass.Methods.Add (speak);

			var sizeReturn = CSReturn.ReturnLine (new CSIdentifier ("Size.Small"));
			var sizeProp = new CSProperty (new CSSimpleType ("Size"), CSMethodKind.None, new CSIdentifier ("Size"),
				CSVisibility.Public, CSCodeBlock.Create (sizeReturn),
				CSVisibility.Public, null);
			altClass.Properties.Add (sizeProp);

			var nameReturn = CSReturn.ReturnLine (new CSFunctionCall ("SwiftString.FromString", false, CSConstant.Val ("FuzzyWuzzy")));
			var nameProp = new CSProperty (new CSSimpleType ("SwiftString"), CSMethodKind.None, new CSIdentifier ("Name"),
				CSVisibility.Public, CSCodeBlock.Create (nameReturn), CSVisibility.Public, null);
			altClass.Properties.Add (nameProp);

			var ctor = new CSMethod (CSVisibility.Public, CSMethodKind.None, null, new CSIdentifier ("FuzzyWuzzy"), new CSParameterList (),
				CSCodeBlock.Create ());
			altClass.Methods.Add (ctor);

			var bearDecl = CSVariableDeclaration.VarLine ("bear", new CSFunctionCall ("FuzzyWuzzy", true));
			var caller = CSFunctionCall.FunctionCallLine ("TopLevelEntities.DescribeBear", false, new CSIdentifier ("bear"));

			var callingCode = CSCodeBlock.Create (bearDecl, caller);
			TestRunning.TestAndExecute (swiftCode, callingCode, "OK\n", otherClass: altClass);
		}

It crashes after accessing the size property.