c++0x 4.4, =default definition outside template class fails.

["Simon Hill" <yacwroy at gmail dot com>]

I've just installed g++ 4.4 and I'm playing with some of the c++0x features.

The below page describes the =default and =delete syntax. (Used to
manipulate the special member functions default/copy constructor,
destructor and copy assign).
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2346.htm

I've managed to get parts of my code working, but it seems that
defining as default a template class's special member functions
outside the class definition doesn't work.
I'm not really sure if it should, but looking at the suggested
modifications to the spec [8.4 paragraph 7] (in the above document), I
_think_ it's saying that it should work.

The problem is that the compiler fails to generate the function
(foo<int>::~foo() in the following code), which causes the linker to
report an undefined reference.

I didn't post this as a bug report as I'm not 100% sure it is a bug.


=== THIS CODE FAILS TO COMPILE ===
template <typename T>
class foo {
  public:
    foo() =default; // <<--- this works fine.
    ~foo();
};

template <typename T>
foo<T>::~foo() =default; <<--- ERROR: This doesn't get built by the compiler.
// foo<T>::~foo() {}; <<-- replacing with this line fixes the error.

int main() {

    foo<int> fi;

    return 0;
}
===================


=== THIS CODE COMPILES ===
class foo {
  public:
    foo() =default;
    ~foo();
};

foo::~foo() =default;

int main() {

    foo fi;
    return 0;

}
===================

NOTE: The reason I noticed this was that I was trying to default a
virtual destructor.
This should work, but I'm guessing that it must be done outside the
function definition, because it doesn't work inside.
However, if the above is a bug, this may also be a bug.