private Type MergeTypes(Type type, Type newType)
{
if (type == null)
{
return(newType);
}
else if (newType == null)
{
return(type);
}
else if (newType.IsAssignableFrom(type))
{
return(newType);
}
else if (type.IsAssignableFrom(newType))
{
return(type);
}
else if (type.IsClass && newType.IsClass)
{
var ss = type.GetTypeChain().Reverse(); // System.Object, ..., X, ..., type
var ts = newType.GetTypeChain().Reverse(); // System.Object, ..., Y, ..., newType
return(Enumerable
.Zip(ss, ts, Tuple.Create)
.Where(t => t.Item1 == t.Item2)
.Last()
.Item1);
}
else if (type == types.Boolean && (newType == types.Int32 || newType == types.Int64))
{
return(newType);
}
else if (newType == types.Boolean && (type == types.Int32 || type == types.Int64))
{
return(type);
}
else if (
(type == types.UInt32 && newType == types.Int32) ||
(type == types.Int32 && newType == types.UInt32))
{
return(newType);
}
else
{
throw new InvalidOperationException("Cannot determine type");
}
}