Example is C/C++ since files mentioned are a header and cpp.
We confirmed VA X does not support your use of nested classes, even when A::B is declared in aclass.h.
As for the crash, we suspect your NCB file is corrupt. The corruption is a common IDE probem. Try exiting your IDE and deleting the NCB files associated with your projects.
We have confirmed the limitation of VA X. Class B must be defined inside class A. To make ourselves feel better, we point out the limitation exists with default IntelliSense.
class A { public: void testA(); class B { public: void testB(); }; };