I believe the following program is well-formed but gcc rejects it with the same error as the one discussed in bug 35722. I'm opening this as a separate bug since unlike in bug 35722, the referenced template is variadic.
$ cat t.C && g++ --version && g++ -std=c++0x t.C template <class T, class ...Types> struct S { typedef typename S<Types...>::type type; }; template <class T> struct S<T> { typedef T type; }; g++ (GCC) 4.5.0 20090404 (experimental) Copyright (C) 2009 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. t.C:3: sorry, unimplemented: cannot expand Types ... into a fixed-length argument list -- Summary: error referencing a more specialized variadic template from primary Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sebor at roguewave dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39653