Hi,
On 04/02/19 15:47, Jason Merrill wrote:
On 2/1/19 3:52 PM, Paolo Carlini wrote:
Hi,
I think that this ICE on invalid (and valid, for c++17+) can be in
fact avoided by accepting in make_typename_type a TYPE_PACK_EXPANSION
as context, thus by not triggering the "‘T ...’ is not a class"
error. Not sure if a better fix would be something more general.
Note, anyway, that we are asserting TYPE_P (context) thus
TYPE_PACK_EXPANSIONs definitely get through beyond MAYBE_CLASS_TYPE_P.
The testcase should test that the using actually works, i.e. imports a
type from a base class.
Uhm, if I change the testcase to something like:
struct B { typedef int type; };
template<typename ...T> struct C : T... {
using typename T::type ...;
void f() { type value; }
};
template class C<B>;
we get a "sorry, unimplemented: use of ‘type_pack_expansion’ in
template" for value, which, arguably, is better than the current ICE,
but I'm not sure if we are close to completing the implementation of
this / we even want to attempt that at this Stage?!?
Thanks, Paolo.
