When working with a project using Script#, I'm finding that Resharper gets confused when dealing with DateTime objects -- which happen to be classes in the Script# core libraries (aacorlib and sscorlib) as compared to mscorlib, where they're a struct. Specifically, it'll complain if you assing null to a DateTime (cannot convert source null to target type System.DateTime) or compare a DateTime to null (cannot apply operator == to operands of type System.DateTime and null).
My suspicion is that Resharper has a hardcoded list of structs somewhere and that DateTime is one of them. However, this clearly isn't the case if you're not using the standard core libraries.
Has anyone else noticed this, or could someone take a look?