[Bug libstdc++/63942] New: [5.0 Regression] constexpr conflicts with previous declaration

[Bug libstdc++/63942] New: [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

            Bug ID: 63942
           Summary: [5.0 Regression] constexpr conflicts with previous
                    declaration
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dje at gcc dot gnu.org

FAIL: 20_util/tuple/comparison_operators/overloaded.cc (test for excess errors)
Excess errors:
/tmp/20141104/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/tuple:102:12:
error: 'constexpr std::_Head_base<_Idx, _Head,
false>::_Head_base(const std::_Head_base<_Idx, _Head, false>&) [with
long unsigned int _Idx = 0ul; _Head = std::nullptr_t]' conflicts with
a previous declaration
/tmp/20141104/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/tuple:102:12:
error: 'constexpr std::_Head_base<_Idx, _Head,
false>::_Head_base(const std::_Head_base<_Idx, _Head, false>&) [with
long unsigned int _Idx = 0ul; _Head = std::nullptr_t]' conflicts with
a previous declaration

FAIL: 20_util/tuple/creation_functions/tuple_cat.cc (test for excess errors)
Excess errors:
/tmp/20141104/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/tuple:102:12:
error: 'constexpr std::_Head_base<_Idx, _Head,
false>::_Head_base(const std::_Head_base<_Idx, _Head, false>&) [with
long unsigned int _Idx = 6ul; _Head = std::nullptr_t]' conflicts with
a previous declaration
/tmp/20141104/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/tuple:102:12:
error: 'constexpr std::_Head_base<_Idx, _Head,
false>::_Head_base(const std::_Head_base<_Idx, _Head, false>&) [with
long unsigned int _Idx = 6ul; _Head = std::nullptr_t]' conflicts with
a previous declaration

[Bug libstdc++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think this must be a front end issue, not libstdc++

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|libstdc++                   |c++
   Target Milestone|---                         |5.0

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

David Edelsohn <dje at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-11-19
                 CC|                            |jason at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from David Edelsohn <dje at gcc dot gnu.org> ---
Confirmed.

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #3 from David Edelsohn <dje at gcc dot gnu.org> ---
Created attachment 34038
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34038&action=edit
preprocessed source for testcase

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #4 from David Edelsohn <dje at gcc dot gnu.org> ---
Created attachment 34039
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34039&action=edit
preprocessed source for testcase

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> ---
I'm not able to reproduce this with a cross compiler at r217823; is it still
happening for you?

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #6 from David Edelsohn <dje at gcc dot gnu.org> ---
It still occurred as of [trunk revision 217822]

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to David Edelsohn from comment #6)
> It still occurred as of [trunk revision 217822]

I'm still not seeing it in a cross-compiler.  Does the error depend on
particular flags?

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[dje at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #8 from David Edelsohn <dje at gcc dot gnu.org> ---
The testsuite invokes compiles overloaded.cc with the following command line on
AIX:

/tmp/20141120/./gcc/xg++ -shared-libgcc -B/tmp/20141120/./gcc -nostdinc++
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/src
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/src/.libs
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/libsupc++/.libs
-B/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/bin/
-B/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/lib/
-isystem
/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/po
werpc-ibm-aix7.1.0.0/include -isystem
/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/sys-include
-B/tmp/20141120/powerpc-ibm-aix7.1.0.0/./libstdc++-v3/src/.libs
-D_GLIBCXX_ASSERT -fmessage-length=0 -ffunction-sections -fdata-sections -g -O2
-DLOCALEDIR="." -nostdinc++
-I/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/powerpc-ibm-aix7.1.0.0
-I/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include
-I/nasfarm/edelsohn/src/src/libstdc++-v3/libsupc++
-I/nasfarm/edelsohn/src/src/libstdc++-v3/include/backward
-I/nasfarm/edelsohn/src/src/libstdc++-v3/testsuite/util
/nasfarm/edelsohn/src/src/libstdc++-v3/testsuite/20_util/tuple/comparison_operators/overloaded.cc
  -std=gnu++11 -S  -o overloaded.s

and tuple_cat.cc command line is:

/tmp/20141120/./gcc/xg++ -shared-libgcc -B/tmp/20141120/./gcc -nostdinc++
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/src
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/src/.libs
-L/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/libsupc++/.libs
-B/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/bin/
-B/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/lib/
-isystem
/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/include
-isystem
/gsa/yktgsa/home/e/d/edelsohn/install/powerpc-ibm-aix7.1.0.0-20141120/powerpc-ibm-aix7.1.0.0/sys-include
-B/tmp/20141120/powerpc-ibm-aix7.1.0.0/./libstdc++-v3/src/.libs
-D_GLIBCXX_ASSERT -fmessage-length=0 -ffunction-sections -fdata-sections -g -O2
-DLOCALEDIR="." -nostdinc++
-I/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include/powerpc-ibm-aix7.1.0.0
-I/tmp/20141120/powerpc-ibm-aix7.1.0.0/libstdc++-v3/include
-I/nasfarm/edelsohn/src/src/libstdc++-v3/libsupc++
-I/nasfarm/edelsohn/src/src/libstdc++-v3/include/backward
-I/nasfarm/edelsohn/src/src/libstdc++-v3/testsuite/util
/nasfarm/edelsohn/src/src/libstdc++-v3/testsuite/20_util/tuple/creation_functions/tuple_cat.cc
  -std=gnu++11 ./libtestc++.a
/gsa/yktgsa/home/e/d/edelsohn/install/lib/libiconv.a  -lm   -o ./tuple_cat.exe

I see -nostdinc++ -std=gnu++11 -g -O2

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #9 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to David Edelsohn from comment #8)
> I see -nostdinc++ -std=gnu++11 -g -O2

Ah, it seems to be triggered by -g.

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> ---
Reduced:

template <class T>
struct A
{
  A(const T&) {}
  A(const A&) {}
};

template class A<decltype(nullptr)>;

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #11 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Fri Nov 21 21:35:09 2014
New Revision: 217950

URL: https://gcc.gnu.org/viewcvs?rev=217950&root=gcc&view=rev
Log:
    PR c++/63942
    * name-lookup.c (supplement_binding_1): Override a mangling alias.
    * mangle.c (implicit_alias_p, remove_implicit_alias): New.
    (mangle_decl): Avoid creating conflicting alias with
    -fabi-compat-version=0, too.
    * cp-tree.h: Adjust.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/nullptr32.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/mangle.c
    trunk/gcc/cp/name-lookup.c

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org

--- Comment #12 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed.

[Bug c++/63942] [5.0 Regression] constexpr conflicts with previous declaration

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63942

--- Comment #13 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Mon Nov 24 12:49:08 2014
New Revision: 218016

URL: https://gcc.gnu.org/viewcvs?rev=218016&root=gcc&view=rev
Log:
    PR c++/63942
    * mangle.c (mangle_decl): If we aren't going to create a symbol
    alias, don't build the alias DECL either.

Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/mangle.c