[Bug c++/106863] New: internal compiler error: in write_template_arg_literal, at cp/mangle.cc:3678

["jehova at existiert dot net" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106863

            Bug ID: 106863
           Summary: internal compiler error: in
                    write_template_arg_literal, at cp/mangle.cc:3678
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jehova at existiert dot net
  Target Milestone: ---

$ g++ --version
g++ (GCC) 12.2.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


$ g++ -c bug.cxx -freport-bug
bug.cxx: In instantiation of ‘decltype ((g(t), (void)0)) f(T) [with T = int]’:
bug.cxx:4:6: internal compiler error: in write_template_arg_literal, at
cp/mangle.cc:3678
    4 | auto f(T t) -> decltype(g(t), void{})
      |      ^
0x19eab38 internal_error(char const*, ...)
        ???:0
0x6546f4 fancy_abort(char const*, int, char const*)
        ???:0
0x728a60 mangle_decl(tree_node*)
        ???:0
0x984016 symbol_table::finalize_compilation_unit()
        ???:0
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://bugs.archlinux.org/> for instructions.
Preprocessed source stored into /tmp/ccL1sCjr.out file, please attach this to
your bugreport.


$ cat bug.cxx 
void g(int);

template <typename T>
auto f(T t) -> decltype(g(t), void{})
{
   return g(t);
}

int main()
{
   f(0);
}


$ cat ccL1sCjr.out 
// Target: x86_64-pc-linux-gnu
// Configured with: /build/gcc/src/gcc/configure
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-bootstrap
--prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--with-build-config=bootstrap-lto --with-linker-hash-style=gnu
--with-system-zlib --enable-__cxa_atexit --enable-cet=auto
--enable-checking=release --enable-clocale=gnu --enable-default-pie
--enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object
--enable-libstdcxx-backtrace --enable-link-serialization=1
--enable-linker-build-id --enable-lto --enable-multilib --enable-plugin
--enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-werror
// Thread model: posix
// Supported LTO compression algorithms: zlib zstd
// gcc version 12.2.0 (GCC) 
// 
// bug.cxx: In instantiation of ‘decltype ((g(t), (void)0)) f(T) [with T =
int]’:
// bug.cxx:4:6: internal compiler error: in write_template_arg_literal, at
cp/mangle.cc:3678
//     4 | auto f(T t) -> decltype(g(t), void{})
//       |      ^
// 0x19eab38 internal_error(char const*, ...)
//      ???:0
// 0x6546f4 fancy_abort(char const*, int, char const*)
//      ???:0
// 0x728a60 mangle_decl(tree_node*)
//      ???:0
// 0x984016 symbol_table::finalize_compilation_unit()
//      ???:0
// Please submit a full bug report, with preprocessed source.
// Please include the complete backtrace with any bug report.
// See <https://bugs.archlinux.org/> for instructions.

// /usr/lib/gcc/x86_64-pc-linux-gnu/12.2.0/cc1plus -quiet -D_GNU_SOURCE bug.cxx
-quiet -dumpbase bug.cxx -dumpbase-ext .cxx -mtune=generic -march=x86-64
-freport-bug -o - -frandom-seed=0 -fdump-noaddr

# 0 "bug.cxx"
# 0 "<built-in>"
# 0 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 0 "<command-line>" 2
# 1 "bug.cxx"
void g(int);

template <typename T>
auto f(T t) -> decltype(g(t), void{})
{
   return g(t);
}

int main()
{
   f(0);
}