[Bug c++/114950] New: [modules] ICE in binding_cmp when merging friend functions in partitions

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114950

            Bug ID: 114950
           Summary: [modules] ICE in binding_cmp when merging friend
                    functions in partitions
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nshead at gcc dot gnu.org
            Blocks: 103524
  Target Milestone: ---

The following code ICEs on trunk:

  // format.h
  template <typename T>
  struct A {
    friend void x();
  };
  template <typename T>
  struct B {
    virtual void f() { A<T> r; }
  };
  template struct B<int>;

  // a.cpp
  module M:a;
  extern "C++" {
    #include "format.h"
  }

  // b.cpp
  module M:b;
  extern "C++" {
    #include "format.h"
  }

  // m.cpp
  export module M;
  import :a;
  import :b;


Compiled with 'g++ -fmodules-ts -S [abm].cpp' results in:

~/ice/m.cpp:1:8: internal compiler error: in binding_cmp, at cp/module.cc:13712
    1 | export module M;
      |        ^~~~~~
0x1018b62 binding_cmp
        ../../gcc/gcc/cp/module.cc:13712
0x3893656 cmp1<sort_ctx>
        ../../gcc/gcc/sort.cc:151
0x3892f8e netsort<sort_ctx>
        ../../gcc/gcc/sort.cc:168
0x38927cd mergesort<sort_ctx>
        ../../gcc/gcc/sort.cc:205
0x389249a gcc_qsort(void*, unsigned long, unsigned long, int (*)(void const*,
void const*))
        ../../gcc/gcc/sort.cc:268
0x1019128 depset::hash::finalize_dependencies()
        ../../gcc/gcc/cp/module.cc:13788
0x1026a71 module_state::write_begin(elf_out*, cpp_reader*,
module_state_config&, unsigned int&)
        ../../gcc/gcc/cp/module.cc:18255
0x102e39f finish_module_processing(cpp_reader*)
        ../../gcc/gcc/cp/module.cc:20693
0xf50556 c_parse_final_cleanups()
        ../../gcc/gcc/cp/decl2.cc:5393
0x131e75f c_common_parse_file()
        ../../gcc/gcc/c-family/c-opts.cc:1329

The issue looks to be that the friend function is added to multiple depsets.


Referenced Bugs:

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