[Bug c++/122699] [16 Regression] ICE in make_dependency, at cp/module.cc:14467

[nshead at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122699

Nathaniel Shead  changed:

   What|Removed |Added

 Status|NEW |RESOLVED
   Assignee|unassigned at gcc dot gnu.org  |nshead at gcc dot 
gnu.org
 Resolution|--- |FIXED

--- Comment #4 from Nathaniel Shead  ---
Should be fixed on trunk, thanks for the report!

[Bug c++/122699] [16 Regression] ICE in make_dependency, at cp/module.cc:14467

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122699

--- Comment #3 from GCC Commits  ---
The master branch has been updated by Nathaniel Shead :

https://gcc.gnu.org/g:e0ac5e1c8a69fec114fc5896cf90b4c0b05240c5

commit r16-5584-ge0ac5e1c8a69fec114fc5896cf90b4c0b05240c5
Author: Nathaniel Shead 
Date:   Sat Nov 22 22:30:32 2025 +1100

c++/modules: Walk indirectly exposed namespaces [PR122699]

In some situations, such as friend injection, we may add an entity to a
namespace without ever explicitly opening that namespace in this TU.

We currently have an additional loop to make sure the namespace is
considered purview, but this isn't sufficient to make
walk_module_binding find it, since the namspace itself is not in the
current TU's symbol table.  This patch ensures we still process the
(hidden) binding for the injected friend in this TU.

PR c++/122699

gcc/cp/ChangeLog:

* name-lookup.h (expose_existing_namespace): Declare.
* name-lookup.cc (expose_existing_namespace): New function.
(push_namespace): Call it.
* pt.cc (tsubst_friend_function): Likewise.

gcc/testsuite/ChangeLog:

* g++.dg/modules/tpl-friend-21_a.C: New test.
* g++.dg/modules/tpl-friend-21_b.C: New test.

Signed-off-by: Nathaniel Shead 
Reviewed-by: Jason Merrill 

[Bug c++/122699] [16 Regression] ICE in make_dependency, at cp/module.cc:14467

[nshead at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122699

--- Comment #2 from Nathaniel Shead  ---
Reduced:

  // a.cpp
  export module M;
  export namespace ns {
template  struct S {
  friend void f();
};
void f();
  }

  // b.cpp
  export module X;
  import M;
  ns::S s;

[Bug c++/122699] [16 Regression] ICE in make_dependency, at cp/module.cc:14467

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122699

Richard Biener  changed:

   What|Removed |Added

   Target Milestone|--- |16.0

[Bug c++/122699] [16 Regression] ICE in make_dependency, at cp/module.cc:14467

[nshead at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122699

Nathaniel Shead  changed:

   What|Removed |Added

 CC||nshead at gcc dot gnu.org
 Ever confirmed|0   |1
 Status|UNCONFIRMED |NEW
 Blocks||103524
   Last reconfirmed||2025-11-16
Summary|ICE in make_dependency, at  |[16 Regression] ICE in
   |cp/module.cc:14467  |make_dependency, at
   ||cp/module.cc:14467
   Keywords||ice-checking

--- Comment #1 from Nathaniel Shead  ---
Confirmed, looks like because of r16-5213 "c++/modules: Maintain attachment of
temploid friends after duplicate_decls [PR122551]". 

The issue here is that `operator|` is now marked as purview and not as imported
(as it's instantiated within M's purview); nevertheless we didn't add it to our
local binding table and so we fail a checking assertion.

Perhaps we should check 'imported_temploid_friends' to consider this an
imported declaration as well... but then, maybe there's good reason we should
be emitting these instantiations from this module as well.  I'll need to think
more and experiment, the behaviour of friends is quite complex and I'm sure I'm
still missing something here.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103524
[Bug 103524] [meta-bug] modules issue