In C++0x mode, enums are allowed to specify an integral type for the base representation. If the enum is inside a class template, it may be a type-dependant expression that should not evaluate and potentially error until instantiation time.
Example code: //======================================== template< typename T > struct wrap { enum E : T { val }; }; template< typename T > struct dependant { enum E : typename T::type { val }; }; template<typename T> struct identity { typedef T type; }; wrap<int> x; dependant<identity<int>> y; //======================================== -- Summary: Cannot parse dependant type for enum-base in C++0x Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: public at alisdairm dot net http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40639