http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660So it would, wow I must've having been having a bad day yesterday! http://ayende.com/3637/safe-for-multi-threading#comment5http://ayende.com/3637/safe-for-multi-threading#comment5Fri, 10 Oct 2008 03:17:16 GMT@Jacob, How does the ordering matter? Am I missing something here? It seems that the recursive call would check the inner type for immutability whether it has been checked or not, wouldn't it? http://ayende.com/3637/safe-for-multi-threading#comment4http://ayende.com/3637/safe-for-multi-threading#comment4Thu, 09 Oct 2008 16:28:07 GMTAhh ok, you are doing that, it's just that it depends on the ordering of types in the GetRootTypesToCheck() collection as to whether it works or not. http://ayende.com/3637/safe-for-multi-threading#comment3http://ayende.com/3637/safe-for-multi-threading#comment3Thu, 09 Oct 2008 03:43:52 GMTIt would also be cool to check if the type of the field was immutable. Otherwise the following would be verified as thread safe, when it's not: class MyClass { private readonly List <int field; // ... } I remember reading a blog article with some good ideas about verifying immutability - [blogs.msdn.com/.../...ng-immutability-in-code.aspx](http://blogs.msdn.com/kevinpilchbisson/archive/2007/11/20/enforcing-immutability-in-code.aspx)>. http://ayende.com/3637/safe-for-multi-threading#comment2http://ayende.com/3637/safe-for-multi-threading#comment2Thu, 09 Oct 2008 03:40:39 GMTHeheh, nice! http://ayende.com/3637/safe-for-multi-threading#comment1http://ayende.com/3637/safe-for-multi-threading#comment1Thu, 09 Oct 2008 01:43:04 GMT