private static ITypeSymbol GetResponseTypeType(AttributeSyntax attribute, SemanticModel semanticModel)
{
var typeofDeclaration = attribute
.GoDown(typeof (AttributeArgumentListSyntax))
.GoDown(typeof (AttributeArgumentSyntax))
.GoDown(typeof (TypeOfExpressionSyntax));
var symbols = typeofDeclaration.ChildNodes().Select(n => semanticModel.GetSymbolInfo(n).Symbol as ITypeSymbol);
return symbols.FirstOrDefault(symbol => symbol != null);
}
