LINQ Issue: Unable to cast object of type 'System.Reflection.Module' to type 'System.Reflection.Emit.ModuleBuilder

Question

I have a simple lambda expression which runs fine as a UNIT test and also runs fine when I copy the code into the Main method of my application. However, when I run the same piece of code within a callback method (via JMS courier) I get the above error. Has anyone encountered this?

Example code failing:

Expression<Func<JupiterDividend, bool>> expr = v => true;
expr.Compile();  // This is what fails

Answer 1

You will normally get this sort of error when a ModuleBuilder has already been 'compiled', or a TypeBuilder has already been 'compiled'.

I would check where such things happen. Also, a stack trace may be handy in this case.

Answer 2

There is a bug report here, not sure though if it is the same issue that you experience. Apparently this has been fixed in .NET 3.5 SP1.