[Bug c++/31323] typename A::B * p; in template definition, with curiously recurring template inheritance
--- Comment #5 from bangerth at dealii dot org 2007-04-08 00:54 --- (In reply to comment #4) ive no idea which part of the standard should imply/allow this. if one replaces typename T::privIC * priv with T * priv, its valid and it compiles. I thought T::privC is equally accessible 'incomplete' as T itself when instantiating the template. Yes, but the difference is that we know what T is (and that it exists) because it was given as a template argument. We don't know this about T::privIC -- it may not exist for certain types given as T, but we can't know without looking into T, which we can't because T isn't complete. I am confident that the code isn't valid because at the point of use T::privIC hasn't been declared yet. Since in addition none of the other compilers you cite support this idiom, I'll close this PR. W. -- bangerth at dealii dot org changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution||INVALID http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31323
[Bug c++/31323] typename A::B * p; in template definition, with curiously recurring template inheritance
--- Comment #3 from bangerth at dealii dot org 2007-03-26 20:46 ---
(In reply to comment #2)
well, priv is a pointer..
What I really meant was a typedef:
template class T struct Base {
typedef typename T::X X;
};
struct A : BaseA
{
typedef int X;
};
But still, what part of the standard makes you think that this should be
valid code?
W.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31323
[Bug c++/31323] typename A::B * p; in template definition, with curiously recurring template inheritance
--- Comment #4 from mesti_mudam at yahoo dot com 2007-03-26 21:49 --- ive no idea which part of the standard should imply/allow this. if one replaces typename T::privIC * priv with T * priv, its valid and it compiles. I thought T::privC is equally accessible 'incomplete' as T itself when instantiating the template. what i want is: class A : public BaseA class B : public BaseB etc. all having the same interface, and all of them's private implementation class is called privC. so either in A, B, etc. or later i'll define class A::privC, class B::privC, etc. maybe we should add this to the standard :) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31323
[Bug c++/31323] typename A::B * p; in template definition, with curiously recurring template inheritance
--- Comment #1 from bangerth at dealii dot org 2007-03-23 06:26 ---
Or smaller like this:
--
template class T struct Base {
typename T::X X;
};
struct A : BaseA
{
typedef int X;
};
--
sunCC also rejects it. I tend to believe that the code is invalid because
at the time where we instantiate BaseA (in the base class list of A), A
is not complete and so the inner typedef is not available yet.
What makes you think that the code should compile?
W.
--
bangerth at dealii dot org changed:
What|Removed |Added
CC||bangerth at dealii dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31323
[Bug c++/31323] typename A::B * p; in template definition, with curiously recurring template inheritance
--- Comment #2 from mesti_mudam at yahoo dot com 2007-03-23 06:42 --- well, priv is a pointer.. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31323
