[Bug c++/67033] [c++11] template argument invalid for integral constant expression beginning with address-of expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67033
Andrew Pinski changed:
What|Removed |Added
Status|NEW |RESOLVED
Target Milestone|--- |6.0
Resolution|--- |FIXED
--- Comment #3 from Andrew Pinski ---
(In reply to Marek Polacek from comment #2)
> Confirmed.
>
> Testcase from PR56428:
This is a different issue overall related to PMF rather than to addresses, I
filed PR 101681 for that.
(In reply to Ed Catmur from comment #1)
> template class X {};
> int i;
> X<&i> x1; // OK
> X<(&(i))> x2; // OK since C++11
> template class Y : X {}; // OK since C++11 if !b
> X x3; // OK since C++1z
GCC 6+ does the correct thing for the testcase in comment #1 so closing.
[Bug c++/67033] [c++11] template argument invalid for integral constant expression beginning with address-of expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67033
Marek Polacek changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed||2019-08-02
CC||mpolacek at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #2 from Marek Polacek ---
Confirmed.
Testcase from PR56428:
template struct Z { };
struct C
{
void f();
Z<&C::f == nullptr> z;
};
[Bug c++/67033] [c++11] template argument invalid for integral constant expression beginning with address-of expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67033
--- Comment #1 from Ed Catmur ---
Created attachment 36075
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36075&action=edit
pr67033.patch
This is kinda ugly.
The problem is that before C++1z, a non-type template argument that evaluates
to the address of or a reference to an object [...] must be expressed as "&
id-expression" [...]; this means that the parser isn't really the place for
this, as the validity of the expression depends on its value:
template class X {};
int i;
X<&i> x1; // OK
X<(&(i))> x2; // OK since C++11
template class Y : X {}; // OK since C++11 if !b
X x3; // OK since C++1z
The attached patch lets through quite a lot of constructs that are actually
invalid pre-C++1z. A rigorous check would be to annotate the constant
expression to say whether it matches the form allowed in [temp.arg.nontype] and
then on evaluation check whether it is a null pointer constant.
