[Bug c++/113340] New: ICE when an explicit object parameter is attempted to be used in a destructor

[Bug c++/113340] New: ICE when an explicit object parameter is attempted to be used in a destructor

[friedkeenan at protonmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

            Bug ID: 113340
           Summary: ICE when an explicit object parameter is attempted to
                    be used in a destructor
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: friedkeenan at protonmail dot com
  Target Milestone: ---

GCC segfaults on the following code:

struct S {
    ~S(this S &) = default;
};

Godbolt link: https://godbolt.org/z/G6rq3ra6W

It should be noted that explicit object parameters are not allowed for
destructors in the first place, but nonetheless an ICE should not occur when it
is attempted.

[Bug c++/113340] ICE when an explicit object parameter is attempted to be used in a destructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |mpolacek at gcc dot gnu.org
   Last reconfirmed|                            |2024-01-11

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed.

[Bug c++/113340] ICE when an explicit object parameter is attempted to be used in a destructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I suppose the following would be one way to fix it:

--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -312,6 +312,12 @@ maybe_retrofit_in_chrg (tree fn)
   basetype = TREE_TYPE (TREE_VALUE (arg_types));
   arg_types = TREE_CHAIN (arg_types);

+  if (!DECL_ARGUMENTS (fn))
+    {
+      gcc_checking_assert (seen_error ());
+      return;
+    }
+
   parms = DECL_CHAIN (DECL_ARGUMENTS (fn));

   /* If this is a subobject constructor or destructor, our caller will

[Bug c++/113340] [14 Regression] ICE when an explicit object parameter is attempted to be used in a destructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE when an explicit object |[14 Regression] ICE when an
                   |parameter is attempted to   |explicit object parameter
                   |be used in a destructor     |is attempted to be used in
                   |                            |a destructor
   Target Milestone|---                         |14.0
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
             Status|NEW                         |ASSIGNED
           Priority|P3                          |P2

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Might be better to leave the 'this' after issuing an error so that the rest of
the code doesn't have to cope.

[Bug c++/113340] [14 Regression] ICE when an explicit object parameter is attempted to be used in a destructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

--- Comment #4 from GCC 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:ac219d524ace47eea5bf5404b267e22950f44030

commit r14-8165-gac219d524ace47eea5bf5404b267e22950f44030
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Jan 16 15:49:46 2024 -0500

    c++: fix ICE with xobj in destructor [PR113340]

    Here we crash in maybe_retrofit_in_chrg on an invalid dtor
    with explicit this.  Such member functions do not get converted
    to METHOD_TYPE.  If a dtor gets parameters, we reset arg_types
    to void_list_node in grokdeclarator.  This results in m_r_in_c
    receiving:
      void <T8d> (void)
    and crashing on
      parms = DECL_CHAIN (DECL_ARGUMENTS (fn));

    This patch avoids the ICE by resetting is_xobj_member_function after
    emitting the error.  Then m_r_in_c gets
      void S::<T40b> (struct S *)
    which does not cause a crash.

            PR c++/113340

    gcc/cp/ChangeLog:

            * decl.cc (grokdeclarator) <case cdk_function>: Clear
            is_xobj_member_function in case of an error.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp23/explicit-obj-diagnostics9.C: New test.

[Bug c++/113340] [14 Regression] ICE when an explicit object parameter is attempted to be used in a destructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113340

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

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

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed.