Mark, in PR c++/11987 you added a comment saying that it was a
regression. But the more I look at it, the less I understand it.
The test case is:
==================================================
template <int dim> struct X {
struct I { I(); };
};
template <int dim> struct Y : X<dim> {
typedef typename X<dim>::I I;
};
template <int dim>
Y<dim>::I::I () {} // note: I is nested type in X, not Y!
template struct Y<1>;
==================================================
g++ currently accepts this test case. The PR says that this test case
is invalid, and should be rejected. But I can't figure out why. The
function definition using a typedef is clearly OK. Is the problem
specifically that this code declares a constructor using a template
specialization? That is, would this code be valid C++?
==================================================
template <int dim> struct X {
struct I { I(); void foo(); };
};
template <int dim> struct Y : X<dim> {
typedef typename X<dim>::I I;
};
template <int dim>
void Y<dim>::I::foo () {}
template struct Y<1>;
==================================================
(Incidentally, this test case currently gets an ICE, but that is
presumably an unrelated problem.)
Or is the problem something else?
For what it's worth, I have a simple patch which rejects this code as
invalid and passes the g++ testsuite. But the patch seems fragile and
wrong. While trying to make the patch correct, I realized that I
don't understand what is correct.
Thanks.
Ian
