[Bug c++/109679] New: export using for functions does not work as specified

[Bug c++/109679] New: export using for functions does not work as specified

[nico at josuttis dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

            Bug ID: 109679
           Summary: export using for functions does not work as specified
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nico at josuttis dot de
  Target Milestone: ---

Consider the following simple module export scenario to wrap a header file in a
module:

//***** foo.hpp:

#ifndef FOO_HPP
#define FOO_HPP

inline int foo()
{
  return 42;
}

#endif // FOO_HPP


//***** foomod.cppm:

module;

#include "foo.hpp"

export module FooMod;

export using ::foo;


//***** testfoo.cpp:

import FooMod;

int main()
{
  return foo();
}


According to the example 2 in "6.6 Program and linkage [basic.link]" and
example 2 in "10.2 Export declaration [module.interface]" this should work
(function f() in both examples).

This is an important feature because it alows programmers to softly migrate
header files to modules.

[Bug c++/109679] export using for functions does not work as specified

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
modules in GCC is still an experimental feature really. And still being
developed.

[Bug c++/109679] export using for functions does not work as specified

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-05-02
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|                            |rejects-valid

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Confirmed.

testfoo.cpp: In function 'int main()':
testfoo.cpp:5:10: error: 'foo' was not declared in this scope
    5 |   return foo();
      |          ^~~

[Bug c++/109679] export using for functions does not work as specified

[admin at hexadigm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

Larry Smith <admin at hexadigm dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |admin at hexadigm dot com

--- Comment #3 from Larry Smith <admin at hexadigm dot com> ---
Likely the same issue I reported here (didn't see yours before posting):

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113129

[Bug c++/109679] export using for functions does not work as specified

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathaniel Shead <nshead@gcc.gnu.org>:

https://gcc.gnu.org/g:63b531e6f8783e8624502d890dc422379de47a9a

commit r14-6978-g63b531e6f8783e8624502d890dc422379de47a9a
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Wed Jan 3 15:29:51 2024 +1100

    c++: Export usings referring to global module fragment [PR109679]

    This patch stops 'add_binding_entity' from ignoring all names in the
    global module fragment, since they should still be exported if named
    in an exported using-declaration.

            PR c++/109679

    gcc/cp/ChangeLog:

            * module.cc (depset::hash::add_binding_entity): Don't skip names
            in the GMF if they've been exported with a using declaration.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/using-11.h: New test.
            * g++.dg/modules/using-11_a.C: New test.
            * g++.dg/modules/using-11_b.C: New test.

    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

[Bug c++/109679] export using for functions does not work as specified

[nshead at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

Nathaniel Shead <nshead at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
           Assignee|unassigned at gcc dot gnu.org      |nshead at gcc dot gnu.org
             Status|NEW                         |RESOLVED
   Target Milestone|---                         |14.0
                 CC|                            |nshead at gcc dot gnu.org

--- Comment #5 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
Fixed for GCC 14.

[Bug c++/109679] export using for functions does not work as specified

[nshead at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109679

--- Comment #6 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
*** Bug 113129 has been marked as a duplicate of this bug. ***