This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [C++0x] Range-based for statements and ADL
- From: Jonathan Wakely <jwakely dot gcc at gmail dot com>
- To: Rodrigo Rivas <rodrigorivascosta at gmail dot com>
- Cc: Jason Merrill <jason at redhat dot com>, gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 31 Mar 2011 21:33:38 +0100
- Subject: Re: [C++0x] Range-based for statements and ADL
- References: <AANLkTi=-PdaK2bni1d7ucHNNP2nSiDeJrnfET-ueaCvF@mail.gmail.com> <AANLkTikxo7955t51av28NhGt4VhA89TyFE6WNPjd_eNE@mail.gmail.com> <AANLkTinP2BzdG+fnO7n=5p+hvaU_VZ+-HyDLNn2Wy2J=@mail.gmail.com> <4D8A2403.5050708@redhat.com> <AANLkTimDRZ94xrA4OPziT7+X-bPK3xfAptTELFpVn-eR@mail.gmail.com> <4D90A209.2020508@redhat.com> <AANLkTintp7fzurBNiiOC+cmRoLt2CF9Q4SwSe04Y1AQa@mail.gmail.com> <AANLkTimWyPccxiYbYG97H9Y6ddHVHFjv+RpgM14tmNyV@mail.gmail.com> <4D94B85F.1030603@redhat.com> <AANLkTik3T3Nd_28tL8+rOo0eZm2j4DATCP4u0OR9EGrK@mail.gmail.com>
On 31 March 2011 21:22, Rodrigo Rivas wrote:
> On Thu, Mar 31, 2011 at 7:22 PM, Jason Merrill <jason@redhat.com> wrote:
>> On 03/28/2011 08:28 PM, Rodrigo Rivas wrote:
>>>
>>> A few comments:
>>> 1. I'm not sure about what should happen if the begin/end found in class
>>> scope are not ordinary functions.
>>
>> Whatever range.begin() would mean if written explicitly.
>>
>>> My guess is that if it is a function
>>> (static or non-static) it is called normally, and if it is a member
>>> variable it is searched for an operator()(). If it is a type it should
>>> fail.
>>
>> Yes, because we can't use . syntax to name type members.
>
> Yeah, actually what I meant is whether:
>
> struct S { typedef int begin, end; };
> //...
> for (auto x : S()) ;
>
> should fall back to ADL or else fail at once. My guess is that is
> should fail, but curiously enough my patch does ADL...
Yes, it should fail because the rules for class member access say that
if E2 is a nested type then the expression E1.E2 is ill-formed (which
is just the formal wording for what Jason said :-)