I have code which looks like:

private static DirectiveNode CreateInstance(Type nodeType, DirectiveInfo info) {
    var ctor = nodeType.GetConstructor(new[] { typeof(DirectiveInfo) });

    if(ctor == null) {
        throw new MissingMethodException(nodeType.FullName, "ctor");
    }

    var node = ctor.Invoke(new[] { info }) as DirectiveNode;

    if(node == null) {
        // ???;
    }

    return node;
}

I am looking for what to do (e.g. what type of exception to throw) when the Invoke method returns something which isn't a DirectiveNode or when it returns null (indicated by // ??? above).

(By the method's contract, nodeType will always describe a subclass of DirectiveNode.)

I am not sure when calling a constructor would return null, so I am not sure if I should handle anything at all, but I still want to be on the safe side and throw an exception if something goes wrong.