[Bug c++/105725] New: [ICE] segfault with `-Wmismatched-tags`

[Bug c++/105725] New: [ICE] segfault with `-Wmismatched-tags`

[tim at klingt dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

            Bug ID: 105725
           Summary: [ICE] segfault with `-Wmismatched-tags`
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tim at klingt dot org
  Target Milestone: ---

possibly a duplicate of 103703, but the backtrace is slightly different, so i'd
file a separate ticket for it:

cwise gave me:
```
template <class T> class T::QPrivateSignal
```

stack trace
```
0xd8e7d3 crash_signal
        ../../src/gcc/toplev.cc:322
0x7f59c77a051f ???
        ./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
0x7ba59e class_decl_loc_t::add(cp_parser*, unsigned int, tag_types, tree_node*,
bool, bool)
        ../../src/gcc/cp/parser.cc:33489
0x7e44ba cp_parser_elaborated_type_specifier
        ../../src/gcc/cp/parser.cc:20659
0x7c8972 cp_parser_type_specifier
        ../../src/gcc/cp/parser.cc:19370
0x7d8e90 cp_parser_type_specifier_seq
        ../../src/gcc/cp/parser.cc:24349
0x7d7214 cp_parser_type_id_1
        ../../src/gcc/cp/parser.cc:24149
0x7d9fb3 cp_parser_template_type_arg
        ../../src/gcc/cp/parser.cc:24257
0x7da119 cp_parser_template_argument
        ../../src/gcc/cp/parser.cc:18799
0x7da119 cp_parser_template_argument_list
        ../../src/gcc/cp/parser.cc:18723
0x7da119 cp_parser_enclosed_template_argument_list
        ../../src/gcc/cp/parser.cc:32029
0x7db50f cp_parser_template_id
        ../../src/gcc/cp/parser.cc:18262
0x7dbcc9 cp_parser_class_name
        ../../src/gcc/cp/parser.cc:25698
0x7d386e cp_parser_qualifying_entity
        ../../src/gcc/cp/parser.cc:7116
0x7d386e cp_parser_nested_name_specifier_opt
        ../../src/gcc/cp/parser.cc:6798
0x7eaa4c cp_parser_simple_type_specifier
        ../../src/gcc/cp/parser.cc:19761
0x7c89d5 cp_parser_type_specifier
        ../../src/gcc/cp/parser.cc:19420
0x7d8e90 cp_parser_type_specifier_seq
        ../../src/gcc/cp/parser.cc:24349
0x7d7214 cp_parser_type_id_1
        ../../src/gcc/cp/parser.cc:24149
0x7d9fb3 cp_parser_template_type_arg
        ../../src/gcc/cp/parser.cc:24257
```

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[tim at klingt dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

--- Comment #1 from tim blechmann <tim at klingt dot org> ---
it also ICEs on valid code:

```
template <bool> struct enable_if;
template <bool _Cond> using enable_if_t = typename enable_if<_Cond>::type;
template <typename> bool is_class_v;
template <class, class> bool IsPrivateSignalArg;
template <class T>
bool IsPrivateSignalArg<T, enable_if_t<is_class_v<class T::QPrivateSignal>>>;
```

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-05-25
     Ever confirmed|0                           |1
                 CC|                            |mpolacek at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
           Keywords|ice-on-invalid-code         |ice-on-valid-code

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed.  Started with r10-7424-g04dd734b52de1218 when the warning was added.

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

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

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:d822f4bbd714c6595f70cc68888dcebecfb6662d

commit r13-803-gd822f4bbd714c6595f70cc68888dcebecfb6662d
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri May 27 10:51:30 2022 -0400

    c++: Fix ICE with -Wmismatched-tags [PR105725]

    Here we ICE with -Wmismatched-tags on something like

      template <class T>
      bool B<T, enable_if_t<is_class_v<class T::foo>>>;

    Specifically, the "class T::foo" bit.  There, class_decl_loc_t::add gets
    a TYPENAME_TYPE as TYPE, rather than a class/union type, so checking
    TYPE_BEING_DEFINED will crash.  I think it's OK to allow a TYPENAME_TYPE to
    slip into that function; we just shouldn't consider the 'class' tag
redundant
    (which works as a 'typename').  In fact, every other compiler *requires*
it.

            PR c++/105725

    gcc/cp/ChangeLog:

            * parser.cc (class_decl_loc_t::add): Check CLASS_TYPE_P.

    gcc/testsuite/ChangeLog:

            * g++.dg/warn/Wmismatched-tags-10.C: New test.

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Marek Polacek
<mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:2c11a9a380e7af333e19d6e576a889646d699b2a

commit r12-8419-g2c11a9a380e7af333e19d6e576a889646d699b2a
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri May 27 10:51:30 2022 -0400

    c++: Fix ICE with -Wmismatched-tags [PR105725]

    Here we ICE with -Wmismatched-tags on something like

      template <class T>
      bool B<T, enable_if_t<is_class_v<class T::foo>>>;

    Specifically, the "class T::foo" bit.  There, class_decl_loc_t::add gets
    a TYPENAME_TYPE as TYPE, rather than a class/union type, so checking
    TYPE_BEING_DEFINED will crash.  I think it's OK to allow a TYPENAME_TYPE to
    slip into that function; we just shouldn't consider the 'class' tag
redundant
    (which works as a 'typename').  In fact, every other compiler *requires*
it.

            PR c++/105725

    gcc/cp/ChangeLog:

            * parser.cc (class_decl_loc_t::add): Check CLASS_TYPE_P.

    gcc/testsuite/ChangeLog:

            * g++.dg/warn/Wmismatched-tags-10.C: New test.

    (cherry picked from commit d822f4bbd714c6595f70cc68888dcebecfb6662d)

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed for GCC 12.2 and 13.

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:bd0c76a2329e7fe6d6612c2259647bbb67f5866a

commit r11-10332-gbd0c76a2329e7fe6d6612c2259647bbb67f5866a
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri May 27 10:51:30 2022 -0400

    c++: Fix ICE with -Wmismatched-tags [PR105725]

    Here we ICE with -Wmismatched-tags on something like

      template <class T>
      bool B<T, enable_if_t<is_class_v<class T::foo>>>;

    Specifically, the "class T::foo" bit.  There, class_decl_loc_t::add gets
    a TYPENAME_TYPE as TYPE, rather than a class/union type, so checking
    TYPE_BEING_DEFINED will crash.  I think it's OK to allow a TYPENAME_TYPE to
    slip into that function; we just shouldn't consider the 'class' tag
redundant
    (which works as a 'typename').  In fact, every other compiler *requires*
it.

            PR c++/105725

    gcc/cp/ChangeLog:

            * parser.c (class_decl_loc_t::add): Check CLASS_TYPE_P.

    gcc/testsuite/ChangeLog:

            * g++.dg/warn/Wmismatched-tags-10.C: New test.

    (cherry picked from commit d822f4bbd714c6595f70cc68888dcebecfb6662d)

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |10.4.0, 11.3.0
      Known to work|                            |11.3.1

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
And eleven based on request.

[Bug c++/105725] [ICE] segfault with `-Wmismatched-tags`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.4