[Bug c++/113332] New: [12/13/14 regression] ICE when building fcitx-5.1.6

[Bug c++/113332] New: [12/13/14 regression] ICE when building fcitx-5.1.6

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

            Bug ID: 113332
           Summary: [12/13/14 regression] ICE when building fcitx-5.1.6
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
  Target Milestone: ---

Created attachment 57038
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57038&action=edit
ibusfrontend.cpp.ii.xz

Originally reported downstream by Toralf Förster at
https://bugs.gentoo.org/921765 with GCC 13 (13.2.1 20231216) but I can
reproduce it with 14 (14.0.0 20240107) too.

```
$ g++ -c ibusfrontend.cpp.ii
In file included from
/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/bits/unique_ptr.h:37,
                 from
/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/memory:78,
                 from
/var/tmp/portage/app-i18n/fcitx-5.1.6/work/fcitx5-5.1.6/src/lib/fcitx/../fcitx-utils/dbus/servicewatcher.h:10,
                 from
/var/tmp/portage/app-i18n/fcitx-5.1.6/work/fcitx5-5.1.6/src/frontend/ibusfrontend/ibusfrontend.h:11,
                 from
/var/tmp/portage/app-i18n/fcitx-5.1.6/work/fcitx5-5.1.6/src/frontend/ibusfrontend/ibusfrontend.cpp:8:
/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/tuple: In substitution of
‘template<class _Dummy, typename
std::enable_if<std::tuple<std::vector<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant>, std::allocator<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant> > >
>::_TCC<std::is_void<_Tp>::value>::__is_implicitly_default_constructible(),
bool>::type <anonymous> > constexpr
std::tuple<std::vector<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant>, std::allocator<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant> > > >::tuple() [with _Dummy = void; typename
std::enable_if<std::tuple<std::vector<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant>, std::allocator<fcitx::dbus::DBusStruct<unsigned char,
fcitx::dbus::Variant> > >
>::_TCC<std::is_void<_Tp>::value>::__is_implicitly_default_constructible(),
bool>::type <anonymous> = <missing>]’:
/var/tmp/portage/app-i18n/fcitx-5.1.6/work/fcitx5-5.1.6/src/frontend/ibusfrontend/ibusfrontend.cpp:594:0:
  recursively required from ‘constexpr
fcitx::dbus::DBusStruct<Args>::DBusStruct() [with Args =
{std::vector<fcitx::dbus::DBusStruct<unsigned char, fcitx::dbus::Variant>,
std::allocator<fcitx::dbus::DBusStruct<unsigned char, fcitx::dbus::Variant> >
>}]’
  594 |     FCITX_OBJECT_VTABLE_PROPERTY(
/var/tmp/portage/app-i18n/fcitx-5.1.6/work/fcitx5-5.1.6/src/frontend/ibusfrontend/ibusfrontend.cpp:594:0:
  required from here
/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14/tuple:763:62: internal
compiler error: in lambda_expr_this_capture, at cp/lambda.cc:825
  763 |           _TCC<_Dummy>::__is_implicitly_default_constructible(),
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
0x55781543e3c2 lambda_expr_this_capture(tree_node*, int)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/lambda.cc:825
0x5578166f2080 maybe_dummy_object(tree_node*, tree_node**)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/tree.cc:4408
0x5578165d0e8e finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**,
bool, bool, int)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/semantics.cc:2968
0x55781678c531 tsubst_expr(tree_node*, tree_node*, int, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:20845
0x5578167bc701 tsubst_template_arg(tree_node*, tree_node*, int, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:12693
0x5578167bc701 tsubst_template_arg(tree_node*, tree_node*, int, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:12681
0x5578167bc701 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:13845
0x557816831076 tsubst_aggr_type_1
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:14120
0x557816831076 tsubst_aggr_type
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:14090
0x5578167093ed tsubst(tree_node*, tree_node*, int, tree_node*)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:16666
0x557816a1a5e2 type_unification_real
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:23316
0x557816a18cb7 fn_type_unification(tree_node*, tree_node*, tree_node*,
tree_node* const*, unsigned int, tree_node*, unification_kind_t, int,
conversion**, bool, bool)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/pt.cc:22390
0x557816a17a82 add_template_candidate_real(z_candidate**, tree_node*,
tree_node*, tree_node*, tree_node*, vec<tree_node*, va_gc, vl_embed> const*,
tree_node*, tree_node*, tree_node*, int, tree_node*, unification_kind_t, bool,
int) [clone .isra.0]
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/call.cc:3631
0x5578165de1b0 add_template_candidate
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/call.cc:3721
0x5578165de1b0 add_candidates
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/call.cc:6686
0x5578168bf6e1 build_new_method_call(tree_node*, tree_node*, vec<tree_node*,
va_gc, vl_embed>**, tree_node*, int, tree_node**, int)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/call.cc:11678
0x557816ce53ee locate_fn_flags
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/method.cc:1964
0x5578166d487d walk_field_subobs
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/method.cc:2555
0x557816c84683 synthesized_method_walk
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/method.cc:2835
0x557816daea87 get_defaulted_eh_spec(tree_node*, int)
       
/usr/src/debug/sys-devel/gcc-14.0.0_pre20240107/gcc-14-20240107/gcc/cp/method.cc:2877
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.gentoo.org/> for instructions.
```

```
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/14/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-14.0.0_pre20240107/work/gcc-14-20240107/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/14
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/14/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/14/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/14/include/g++-v14
--disable-silent-rules --disable-dependency-tracking
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/14/python
--enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --enable-nls --without-included-gettext
--disable-libunwind-exceptions --enable-checking=yes,extra,rtl
--with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo Hardened
14.0.0_pre20240107 p15' --with-gcc-major-version-only --enable-libstdcxx-time
--enable-lto --disable-libstdcxx-pch --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --enable-multilib
--with-multilib-list=m32,m64 --disable-fixed-point --enable-targets=all
--enable-libgomp --disable-libssp --disable-libada --enable-cet
--disable-systemtap --enable-valgrind-annotations --disable-vtable-verify
--disable-libvtv --with-zstd --with-isl --disable-isl-version-check
--enable-default-pie --enable-host-pie --enable-host-bind-now
--enable-default-ssp --with-build-config='bootstrap-O3 bootstrap-lto
bootstrap-cet'
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20240107 (experimental) (Gentoo Hardened 14.0.0_pre20240107
p15)
```

[Bug c++/113332] [12/13/14 regression] ICE when building fcitx-5.1.6

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |12.4

[Bug c++/113332] [12/13/14 regression] ICE when building fcitx-5.1.6

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 57041
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57041&action=edit
invalid.ii

Here's an invalid reduced version. Re-reducing...

[Bug c++/113332] [12/13/14 regression] ICE when building fcitx-5.1.6

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2024-01-11
     Ever confirmed|0                           |1
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=105637
                 CC|                            |ppalka at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Started with r13-984-g44a5bd6d933d86

[Bug c++/113332] [12/13/14 regression] checking ICE when building fcitx-5.1.6

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

--- Comment #3 from Sam James <sjames at gcc dot gnu.org> ---
Created attachment 57072
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57072&action=edit
reduced.ii

[Bug c++/113332] [12/13/14 regression] checking ICE when building fcitx-5.1.6

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Another reduced valid testcase:

struct tuple {
  template<class _Tp>
  static constexpr bool __is_implicitly_default_constructible() { return true;
}

  template<class _Tp = void,
           bool = __is_implicitly_default_constructible<_Tp>()>
  tuple();
};

struct DBusStruct {
  DBusStruct() = default;
  tuple data_;
};

struct IBusService {
  int m = [] { DBusStruct{}; return 42; }();
};

[Bug c++/113332] [12/13/14 regression] checking ICE when building fcitx-5.1.6

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:9bc6b23d11697545e8a951ccd60691b1e58b98c2

commit r14-8981-g9bc6b23d11697545e8a951ccd60691b1e58b98c2
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Feb 14 10:20:31 2024 -0500

    c++: synthesized_method_walk context independence [PR113908]

    In the second testcase below, during ahead of time checking of the
    non-dependent new-expr we synthesize B's copy ctor, which we expect to
    get defined as deleted since A's copy ctor is inaccessible.  But during
    access checking thereof, enforce_access incorrectly decides to defer it
    since we're in a template context according to current_template_parms
    (before r14-557 it checked processing_template_decl which got cleared
    from implicitly_declare_fn), which leads to the access check leaking out
    to the template context that triggered the synthesization, and B's copy
    ctor getting declared as non-deleted.

    This patch fixes this by using maybe_push_to_top_level to clear the
    context (including current_template_parms) before proceeding with the
    synthesization.  We could do this from implicitly_declare_fn, but it's
    better to do it more generally from synthesized_method_walk for sake of
    its other callers.

    This turns out to fix PR113332 as well: there the lambda context
    triggering synthesization was causing maybe_dummy_object to misbehave,
    but now synthesization is sufficiently context-independent.

            PR c++/113908
            PR c++/113332

    gcc/cp/ChangeLog:

            * method.cc (synthesized_method_walk): Use maybe_push_to_top_level.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/lambda/lambda-nsdmi11.C: New test.
            * g++.dg/template/non-dependent31.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>

[Bug c++/113332] [12/13 regression] checking ICE when building fcitx-5.1.6

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org

[Bug c++/113332] [12/13 regression] checking ICE when building fcitx-5.1.6

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/113332] [12/13 regression] checking ICE when building fcitx-5.1.6

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113332

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|12.4                        |14.0

--- Comment #6 from Patrick Palka <ppalka at gcc dot gnu.org> ---
It doesn't seem worth backporitng this relatively risky patch just to fix a
checking-only assertion failure that we otherwise gracefully handle.