This isn't a very serious issue, but it is interesting. VB.NET calls RuntimeHelpers.GetObjectValue() every time an object reference gets assigned to a field or passed as a parameter. The idea is that boxed value types behave as values (i.e. they get copied every time you assign them) (see runtimehelpers.cs in the Rotor source).
The problem is as follows: When GetObjectValue() is passed an "immutable" value type, it just returns the same object. This is incorrect, because boxes aren't *ever* immutable. The contents of a box can always be changed (because the unbox CIL instruction returns a *reference* to the contents of the box). Since the list won't allow attachments, the demonstration code can be downloaded here (4 KB): http://www.frijters.net/boxchanger.zip The zip includes: boxchanger.il -- static method to change to contents of a boxed Int32 test.vb -- demonstration of inconsistent behaviour boxchanger.dll test.exe Please note that both test.exe & boxchanger.dll are fully verifiable. Regards, Jeroen
