C++: Test showing going from a forward class declaration to a class but not back

cpp/ql/test/library-tests/declarationEntry/declarationEntry/declarationEntry.cpp

@@ -33,3 +33,11 @@ public:
 
 myTemplateClass<int> mtc_int;
 myTemplateClass<short> mtc_short;
+
+// Class (UserType)
+
+class myClass
+{
+public:
+	int myMemberVariable;
+};