GCC version 2.95.1 19990809 (prerelease) 
Checkout on gcc-2_95-branch made on August 9th @ 10am EDT.

--------------
class AA { protected:
  template <class T> struct BB { T x; BB(const T &x) : x(x) { }; };
  template <class T> struct CC : public BB<T> { CC(const T &x) : BB<T>(x) { };
};
};
--------------
gcc --save-temps -c bug.cpp
bug.cpp:3: Internal compiler error.
bug.cpp:3: Please submit a full bug report.
bug.cpp:3: See <URL:http://www.gnu.org/software/gcc/faq.html#bugreport> for
instructions.

Nothing useful in bug.ii.

Note: 
Replacing       class AA { protected:
by              namespace AA {
works.

- Leon Bottou