Re: Invalid C++ or bug in GCC 4.8

I was quite unhappy to find out that code I've written years ago
suddenly fails to compile with the latest GCC (4.8). It compiles
without warning (with -Wall and -Wextra) with GCC 4.7.3 as well as
with Clang 3.2.

Below is a completely stripped down version of the code. Is this
illegal C++ code, or is this a bug in GCC 4.8?

<code>
template <typename Signature, typename TypeId> class ObjectFactory;

template<typename Base , typename TypeId>
class ObjectFactory<Base (), TypeId> { };

struct Abstract { virtual ~Abstract() = 0; };

struct Concrete : Abstract { };

typedef ObjectFactory< Abstract(), int> MyFactory;
</code>

When compiling with GCC 4.8 I get the following error:

Eabstract-class-type.cc:10:33: error: ?type name? declared as
function returning an abstract class type
  typedef ObjectFactory< Abstract(), int> MyFactory;