[Bug c++/54903] New: Auto + static in-class constant initalization not working

[Bug c++/54903] New: Auto + static in-class constant initalization not working

[rhalbersma at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54903

             Bug #: 54903
           Summary: Auto + static in-class constant initalization not
                    working
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rhalbersma@gmail.com


template<int N, int D>
struct Modulus
{
        static auto const value = N % D;
};

template<int N>
struct Angle
{
        static auto const value = Modulus<N, 360>::value; // ERROR
        //static int const value = Modulus<N, 360>::value;  // OK
        //static auto const value = N % 360;                // OK

        typedef Angle<value> type;
};

I cannot do static auto const = Modulus<N, 360>::value, with either MinGW gcc
4.7.2 (Nuwen distro) or Ideone (gcc 4.5.1). Instead, I have to either
explicitly denote the type as static int const value = Modulus<N, 360>::value
or I have to use auto with the full modular expression as static auto const
value = N % 360;.

The code appears to be Standard compliant and works on both Visual C++ 2010
Express and Clang 3.1

Link to Stackoverflow: http://stackoverflow.com/q/12834874/819272

[Bug c++/54903] [4.8 Regression] Auto + static in-class constant initalization not working

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54903

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-11
                 CC|                            |jason at gcc dot gnu.org
   Target Milestone|---                         |4.8.0
            Summary|Auto + static in-class      |[4.8 Regression] Auto +
                   |constant initalization not  |static in-class constant
                   |working                     |initalization not working
     Ever Confirmed|0                           |1

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-11 22:53:25 UTC ---
In terms of FSF releases, this is accepted by all the 4.7.x releases up to
current 4_7-branch. It's not accepted by current mainline with:

54903.C:14:23: error: use of ‘Angle<N>::value’ before deduction of ‘auto’
         typedef Angle<value> type;
                       ^
54903.C:14:23: error: use of ‘Angle<N>::value’ before deduction of ‘auto’

Thus it seems a Regression (if anything ;)

[Bug c++/54903] [4.8 Regression] Auto + static in-class constant initalization not working

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54903

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-10-12 08:12:23 UTC ---
Started with http://gcc.gnu.org/viewcvs?view=revision&revision=185768

[Bug c++/54903] [4.8 Regression] Auto + static in-class constant initialization not working

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54903

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2012-11-15 16:12:03 UTC ---
Author: jason
Date: Thu Nov 15 16:11:56 2012
New Revision: 193535

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193535
Log:
    PR c++/54903
    * decl2.c (mark_used): Don't complain about auto in templates.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/auto36.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl2.c

[Bug c++/54903] [4.8 Regression] Auto + static in-class constant initialization not working

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54903

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2012-11-15 16:47:45 UTC ---
Fixed.