[Bug c++/106363] New: [modules] Can't selectively reexport imported declaration in same namespace

[Bug c++/106363] New: [modules] Can't selectively reexport imported declaration in same namespace

[johelegp at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

            Bug ID: 106363
           Summary: [modules] Can't selectively reexport imported
                    declaration in same namespace
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: johelegp at gmail dot com
                CC: johelegp at gmail dot com
  Target Milestone: ---

See https://godbolt.org/z/a3GqTEs5P, which Clang accepts:
https://godbolt.org/z/svaGvz1bz.

mod2.cpp:
```C++
export module mod2;
namespace ns {
export int x = 0;
}
```

mod.cpp:
```C++
export module mod;
import mod2;
namespace ns {
export using ns::x;
}
```

test.cpp:
```C++
import mod;
int main() { return ns::x; }
```

Output:
```
[ 62%] Building CXX object CMakeFiles/mod.dir/mod.cpp.o
mod.cpp:1:8: internal compiler error: in decl_node, at cp/module.cc:8678
    1 | export module mod;
      |        ^~~~~~
0x221f229 internal_error(char const*, ...)
        ???:0
0x74c10d fancy_abort(char const*, int, char const*)
        ???:0
0x8fcc60 trees_out::decl_node(tree_node*, walk_kind)
        ???:0
0x8fd01d trees_out::tree_node(tree_node*)
        ???:0
0x905086 module_state::write_cluster(elf_out*, depset**, unsigned int,
depset::hash&, unsigned int*, unsigned int*)
        ???:0
0x906ace module_state::write_begin(elf_out*, cpp_reader*, module_state_config&,
unsigned int&)
        ???:0
0x9079f2 finish_module_processing(cpp_reader*)
        ???:0
0x87253d c_parse_final_cleanups()
        ???:0
0xb2d060 c_common_parse_file()
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
```

[Bug c++/106363] [13 Regression] [modules] Can't selectively reexport imported declaration in same namespace

[johelegp at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

Johel Ernesto Guerrero Peña <johelegp at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[modules] Can't selectively |[13 Regression] [modules]
                   |reexport imported           |Can't selectively reexport
                   |declaration in same         |imported declaration in
                   |namespace                   |same namespace

--- Comment #1 from Johel Ernesto Guerrero Peña <johelegp at gmail dot com> ---
Reexporting is not the problem. The _using-declaration_ is.

Reproducer script:
```bash
#!/bin/bash
CXX=g++
echo "mod2 mod2.gcm
mod mod.gcm" > mm.txt
echo "export module mod2;
namespace ns {
export int x = 0;
}" > mod2.cpp
echo "export module mod;
import mod2;
namespace ns {
export using ns::x;
}" > mod.cpp
$CXX -std=c++23 -fmodules-ts -fmodule-mapper=mm.txt -c mod2.cpp
$CXX -std=c++23 -fmodules-ts -fmodule-mapper=mm.txt -c mod.cpp
```

[Bug c++/106363] [13 Regression] [modules] ICE using-declaration of imported name in the same namespace

[johelegp at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

Johel Ernesto Guerrero Peña <johelegp at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |12.2.0
      Known to fail|                            |13.0

--- Comment #2 from Johel Ernesto Guerrero Peña <johelegp at gmail dot com> ---
GCC 12.2 accepts: https://godbolt.org/z/4ExevrnWx.

[Bug c++/106363] [13 Regression] [modules] ICE using-declaration of imported name in the same namespace

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0

[Bug c++/106363] [13 Regression] [modules] ICE using-declaration of imported name in the same namespace

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2022-12-22
           Keywords|                            |ice-checking
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  We run into

...
#if CHECKING_P
      gcc_assert (!import || importedness >= 0);
#endif

likely also an issue on the branch, but I didn't check.

[Bug c++/106363] [13/14 Regression] [modules] ICE using-declaration of imported name in the same namespace

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.0                        |13.2

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.1 is being released, retargeting bugs to GCC 13.2.

[Bug c++/106363] [13/14 Regression] [modules] ICE using-declaration of imported name in the same namespace

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|13.2                        |13.3

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 13.2 is being released, retargeting bugs to GCC 13.3.

[Bug c++/106363] [13/14 Regression] [modules] ICE using-declaration of imported name in the same namespace

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

--- Comment #6 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:cb76f46c97e9f4e4869acceb77a000b6cc2cda0e

commit r14-6636-gcb76f46c97e9f4e4869acceb77a000b6cc2cda0e
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Sun Nov 12 11:54:43 2023 +1100

    c++: Seed namespaces for bindings [PR106363]

    Currently the first depset for an EK_BINDING is not seeded. This breaks
    the attached testcase as then the namespace is not considered referenced
    yet during streaming, but we've already finished importing.

    There doesn't seem to be any particular reason I could find for skipping
    the first depset for bindings, and removing the condition doesn't appear
    to cause any test failures, so this patch removes that check.

            PR c++/106363

    gcc/cp/ChangeLog:

            * module.cc (module_state::write_cluster): Don't skip first
            depset for bindings.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/pr106363_a.C: New test.
            * g++.dg/modules/pr106363_b.C: New test.

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

[Bug c++/106363] [13 Regression] [modules] ICE using-declaration of imported name in the same namespace

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[13/14 Regression]          |[13 Regression] [modules]
                   |[modules] ICE               |ICE using-declaration of
                   |using-declaration of        |imported name in the same
                   |imported name in the same   |namespace
                   |namespace                   |
                 CC|                            |law at gcc dot gnu.org

--- Comment #7 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Fixed on the trunk.

[Bug c++/106363] [13 Regression] [modules] ICE using-declaration of imported name in the same namespace

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106363

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED
                 CC|                            |ppalka at gcc dot gnu.org
   Target Milestone|13.3                        |14.0

--- Comment #8 from Patrick Palka <ppalka at gcc dot gnu.org> ---
IIUC this checking-only ICE is not actually a regression so let's mark this as
fixed for 14 only.