[Bug c++/109319] New: [13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793

[Bug c++/109319] New: [13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

            Bug ID: 109319
           Summary: [13 Regression] ICE in build_min_non_dep_op_overload,
                    at cp/tree.cc:3793
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Started between 20221106 and 20221120, with -std=c++23 :
(follow-up of pr108437)


$ cat z1.cc
struct S
{
  static int operator[] (int x) { int a[2]; return a[x]; }
};
template<class T> int f ()
{
  S s;
  ++s[0,1];
  return 0;
}


$ cat z2.cc
struct S
{
  static int operator[] (int x) { int a[2]; return a[x]; }
};
template<class T> int f ()
{
  S s;
  ++s[1,0];
  return 0;
}


$ g++-13-20230326 -c z1.cc -std=c++23
z1.cc: In function 'int f()':
z1.cc:8:6: warning: top-level comma expression in array subscript changed
meaning in C++23 [-Wcomma-subscript]
    8 |   ++s[0,1];
      |      ^
z1.cc:8:10: internal compiler error: in build_min_non_dep_op_overload, at
cp/tree.cc:3793
    8 |   ++s[0,1];
      |          ^
0x8de226 build_min_non_dep_op_overload(tree_node*, tree_node*, tree_node*,
vec<tree_node*, va_gc, vl_embed>*)
        ../../gcc/cp/tree.cc:3793
0x7ad99d grok_array_decl(unsigned int, tree_node*, tree_node*, vec<tree_node*,
va_gc, vl_embed>**, int)
        ../../gcc/cp/decl2.cc:569
0x843ca4 cp_parser_postfix_open_square_expression
        ../../gcc/cp/parser.cc:8223
0x856671 cp_parser_postfix_expression
        ../../gcc/cp/parser.cc:7814
0x86a60f cp_parser_unary_expression
        ../../gcc/cp/parser.cc:9141
0x83e79f cp_parser_cast_expression
        ../../gcc/cp/parser.cc:10045
0x86a707 cp_parser_unary_expression
        ../../gcc/cp/parser.cc:9055
0x83e79f cp_parser_cast_expression
        ../../gcc/cp/parser.cc:10045
0x83f07f cp_parser_binary_expression
        ../../gcc/cp/parser.cc:10147
0x83fa74 cp_parser_assignment_expression
        ../../gcc/cp/parser.cc:10490
0x8411b2 cp_parser_expression
        ../../gcc/cp/parser.cc:10660
0x844837 cp_parser_expression_statement
        ../../gcc/cp/parser.cc:12816
0x851cbc cp_parser_statement
        ../../gcc/cp/parser.cc:12596
0x852d54 cp_parser_statement_seq_opt
        ../../gcc/cp/parser.cc:12967
0x852e0f cp_parser_compound_statement
        ../../gcc/cp/parser.cc:12919
0x873958 cp_parser_function_body
        ../../gcc/cp/parser.cc:25335
0x873958 cp_parser_ctor_initializer_opt_and_function_body
        ../../gcc/cp/parser.cc:25386
0x873e16 cp_parser_function_definition_after_declarator
        ../../gcc/cp/parser.cc:32012
0x874f90 cp_parser_function_definition_from_specifiers_and_declarator
        ../../gcc/cp/parser.cc:31929
0x874f90 cp_parser_init_declarator
        ../../gcc/cp/parser.cc:22789

[Bug c++/109319] [13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-03-28
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |mpolacek at gcc dot gnu.org

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r13-4046-g6492cec069bccf:

commit 6492cec069bccf817ac5e984fb3eca407056a566
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Nov 15 08:00:21 2022 +0100

    c++: Implement C++23 P2589R1 - - static operator[]

[Bug c++/109319] [13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-checking

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
With release checking I see

t.C:3:14: warning: 'static int S::operator[](int)' may be a static member
function only with '-std=c++23' or '-std=gnu++23' [-Wc++23-extensions]
    3 |   static int operator[] (int x) { int a[2]; return a[x]; }
      |              ^~~~~~~~
t.C: In function 'int f()':
t.C:8:10: error: lvalue required as increment operand
    8 |   ++s[0,1];
      |          ^
t.C: At global scope:
t.C:13:1: error: '$' does not name a type
   13 | $ cat z2.cc
      | ^
t.C:18:23: error: redefinition of 'template<class T> int f()'
   18 | template<class T> int f ()
      |                       ^
t.C:5:23: note: 'template<class T> int f()' previously declared here
    5 | template<class T> int f ()
      |                       ^

[Bug c++/109319] [12/13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
            Summary|[13 Regression] ICE in      |[12/13 Regression] ICE in
                   |build_min_non_dep_op_overlo |build_min_non_dep_op_overlo
                   |ad, at cp/tree.cc:3793      |ad, at cp/tree.cc:3793
                   |                            |since r12-5510

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> With release checking I see

Those are two separate testcases which just differ in 0,1 vs. 1,0.

Anyway, adjusted testcase so that it isn't so invalid:
struct S
{
  static int &operator[] (int x) { static int a[2]; return a[x]; }
};

template <int N>
int
foo ()
{
  S s;
  ++s[0, 1];
  return 0;
}
and without the template <int N> line is accepted with a pedwarn.
And, if it is changed to:
struct S
{
  int &operator[] (int x) { static int a[2]; return a[x]; }
};

template <int N>
int
foo ()
{
  S s;
  ++s[0, 1];
  return 0;
}
then it is also accepted with pedwarn without the template <int N> line and
otherwise ICEs already starting with r12-5510-gb38c9cf6d570f6.

[Bug c++/109319] [12/13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 54785
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54785&action=edit
gcc13-pr109319.patch

Untested fix.

[Bug c++/109319] [12/13 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:c016887c91a79d67b6a3c7e19b9219f5ab1e2a4d

commit r13-6946-gc016887c91a79d67b6a3c7e19b9219f5ab1e2a4d
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 30 23:08:25 2023 +0200

    c++: Fix up ICE in build_min_non_dep_op_overload [PR109319]

    The following testcase ICEs, because grok_array_decl during
    processing_template_decl handling of a non-dependent subscript
    emits a -Wcomma-subscript pedwarn, we decide to pass to the
    single index argument the index expressions as if it was wrapped
    with () around it, but then when preparing it for later instantiation
    we don't actually take that into account and ICE on a mismatch of
    number of index arguments (the overload expects a single index,
    testcase has two index expressions in this case).
    For non-dependent subscript which are builtin subscripts we also
    emit the same pedwarn and don't ICE, but emit the same pedwarn
    again whenever we instantiate it, which is also IMHO undesirable,
    it is enough to warn once during parsing the template.

    The following patch fixes it by turning even the original index expressions
    (those which didn't go through make_args_non_dependent) into a single
    index using comma expression(s).

    2023-03-30  Jakub Jelinek  <jakub@redhat.com>

            PR c++/109319
            * decl2.cc (grok_array_decl): After emitting a pedwarn for
            -Wcomma-subscript, if processing_template_decl set orig_index_exp
            to compound expr from orig_index_exp_list.

            * g++.dg/cpp23/subscript14.C: New test.

[Bug c++/109319] [12 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[12/13 Regression] ICE in   |[12 Regression] ICE in
                   |build_min_non_dep_op_overlo |build_min_non_dep_op_overlo
                   |ad, at cp/tree.cc:3793      |ad, at cp/tree.cc:3793
                   |since r12-5510              |since r12-5510

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed on the trunk so far.

[Bug c++/109319] [12 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:6a5c0588ac00f6f55ae7ed2bb791e7e119a01c43

commit r12-9425-g6a5c0588ac00f6f55ae7ed2bb791e7e119a01c43
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 30 23:08:25 2023 +0200

    c++: Fix up ICE in build_min_non_dep_op_overload [PR109319]

    The following testcase ICEs, because grok_array_decl during
    processing_template_decl handling of a non-dependent subscript
    emits a -Wcomma-subscript pedwarn, we decide to pass to the
    single index argument the index expressions as if it was wrapped
    with () around it, but then when preparing it for later instantiation
    we don't actually take that into account and ICE on a mismatch of
    number of index arguments (the overload expects a single index,
    testcase has two index expressions in this case).
    For non-dependent subscript which are builtin subscripts we also
    emit the same pedwarn and don't ICE, but emit the same pedwarn
    again whenever we instantiate it, which is also IMHO undesirable,
    it is enough to warn once during parsing the template.

    The following patch fixes it by turning even the original index expressions
    (those which didn't go through make_args_non_dependent) into a single
    index using comma expression(s).

    2023-03-30  Jakub Jelinek  <jakub@redhat.com>

            PR c++/109319
            * decl2.cc (grok_array_decl): After emitting a pedwarn for
            -Wcomma-subscript, if processing_template_decl set orig_index_exp
            to compound expr from orig_index_exp_list.

            * g++.dg/cpp23/subscript14.C: New test.

    (cherry picked from commit c016887c91a79d67b6a3c7e19b9219f5ab1e2a4d)

[Bug c++/109319] [12 Regression] ICE in build_min_non_dep_op_overload, at cp/tree.cc:3793 since r12-5510

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109319

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed also for 12.3.