[Bug c++/67746] New: Mangled name is accepted for variables in namespace-scope

[Bug c++/67746] New: Mangled name is accepted for variables in namespace-scope

[roger.ferrer at bsc dot es]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67746

            Bug ID: 67746
           Summary: Mangled name is accepted for variables in
                    namespace-scope
           Product: gcc
           Version: 5.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: roger.ferrer at bsc dot es
  Target Milestone: ---

Hi,

this was discovered by accident.

g++ 5.2.0 accepts this

 namespace N
 {
   int x;
 }

 void f(void)
 {
   _ZN1N1xE = 1; // somehow this is an alias to N::x at the eyes of the C++FE
 }

but rejects other cases that have the same mangling (according to "nm") like

 struct N
 {
   static int x;
 };

 void f(void)
 {
   _ZN1N1xE = 1; // rejected
 }

The following case is not allowed either, which suggests that the mangled name
is added into some scope after the declarator has been processed.

 namespace N
 {
   int x = _ZN1N1xE; // rejected
 }

Next case is accepted, again suggesting that after the init-declarator 'x = 3'
has been consumed, the mangled name is added into some scope.

 namespace N
 {
   int x = 3, y = _ZN1N1xE; // accepted
 }

I understand that underscore-prefixed names may belong to the implementation,
but given that other similar cases are rejected, perhaps this one can be
rejected as well.

Kind regards,

[Bug c++/67746] Mangled name is accepted for variables in namespace-scope

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67746

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Your examples are undefined due to the use of reserved names, and the libstdc++
implementation actually relies on this in places, so I think changing it would
break things.

[Bug c++/67746] Mangled name is accepted for variables in namespace-scope

[roger.ferrer at bsc dot es]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67746

--- Comment #2 from Roger Ferrer Ibanez <roger.ferrer at bsc dot es> ---
(In reply to Jonathan Wakely from comment #1)
> Your examples are undefined due to the use of reserved names, and the
> libstdc++ implementation actually relies on this in places, so I think
> changing it would break things.

Ah ok, I didn't know this was used in the libstdc++.

Thanks,

[Bug c++/67746] Mangled name is accepted for variables in namespace-scope

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67746

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |8.0
      Known to work|                            |8.1.0
           Keywords|                            |accepts-invalid
      Known to fail|                            |7.5.0

[Bug c++/67746] Mangled name is accepted for variables in namespace-scope

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67746

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

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

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://gcc.gnu.org/legacy-ml/gcc-patches/2017-10/msg00199.html

Fixed for GCC 8 by r8-3605.