[Bug c++/109300] New: [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279

[Bug c++/109300] New: [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

            Bug ID: 109300
           Summary: [13 Regression] ICE in cp_finish_decl, at
                    cp/decl.cc:8279
           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 20230226 and 20230312 :


$ cat z1.cc
template<typename T>
auto x = [](){ x<int>(); };


$ gcc-13-20230326 -c z1.cc
z1.cc: In instantiation of 'auto x<int>':
z1.cc:2:16:   required from here
z1.cc:2:6: internal compiler error: in cp_finish_decl, at cp/decl.cc:8279
    2 | auto x = [](){ x<int>(); };
      |      ^
0x7a8893 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        ../../gcc/cp/decl.cc:8279
0x899b2a instantiate_body
        ../../gcc/cp/pt.cc:26799
0x89aa6f instantiate_decl(tree_node*, bool, bool)
        ../../gcc/cp/pt.cc:27121
0x7b210a maybe_instantiate_decl(tree_node*)
        ../../gcc/cp/decl2.cc:5448
0x7b2c62 mark_used(tree_node*, int)
        ../../gcc/cp/decl2.cc:5747
0x8cc5c3 finish_id_expression_1
        ../../gcc/cp/semantics.cc:4269
0x8cc5c3 finish_id_expression(tree_node*, tree_node*, tree_node*, cp_id_kind*,
bool, bool, bool*, bool, bool, bool, bool, char const**, unsigned int)
        ../../gcc/cp/semantics.cc:4411
0x853ecf cp_parser_primary_expression
        ../../gcc/cp/parser.cc:6149
0x856e76 cp_parser_postfix_expression
        ../../gcc/cp/parser.cc:7777
0x86a60f cp_parser_unary_expression
        ../../gcc/cp/parser.cc:9141
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
0x853967 cp_parser_function_body
        ../../gcc/cp/parser.cc:25335
0x853967 cp_parser_lambda_body
        ../../gcc/cp/parser.cc:11837

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-03-27
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|ice-on-valid-code           |ice-on-invalid-code,
                   |                            |needs-bisection

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note I think this is invalid code.

With an instantation, GCC 12 (and before) does reject it:
```
template<typename T>
auto x = [](){ x<int>(); };
auto y = x<int>;
```
```
<source>: In instantiation of 'auto x<int>':
<source>:3:10:   required from here
<source>:2:16: error: use of 'x<int>' before deduction of 'auto'
    2 | auto x = [](){ x<int>(); };
      |                ^~~~~~
<source>:2:6: error: 'x<int>' has incomplete type
    2 | auto x = [](){ x<int>(); };
      |      ^
<source>:2:22: error: invalid use of 'auto'
    2 | auto x = [](){ x<int>(); };
      |                ~~~~~~^~
```
Note clang rejects it even without an instantation.

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
           Keywords|needs-bisection             |
            Summary|[13 Regression] ICE in      |[13 Regression] ICE in
                   |cp_finish_decl, at          |cp_finish_decl, at
                   |cp/decl.cc:8279             |cp/decl.cc:8279 since
                   |                            |r13-6380-gd3d205ab44088616

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r13-6380-gd3d205ab44088616.

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
   Target Milestone|---                         |13.0
                 CC|                            |mpolacek at gcc dot gnu.org

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

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

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

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P1

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

--- Comment #3 from CVS 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:c37ed38ada788ae410c48ec6d8c9b5d9f32ab8cf

commit r13-6989-gc37ed38ada788ae410c48ec6d8c9b5d9f32ab8cf
Author: Patrick Palka <ppalka@redhat.com>
Date:   Mon Apr 3 18:49:37 2023 -0400

    c++: ICE with loopy var tmpl auto deduction [PR109300]

    Now that we resolve non-dependent variable template-ids ahead of time,
    cp_finish_decl needs to handle a new invalid situation: we can end up
    trying to instantiate a variable template with deduced type before we
    fully parsed its initializer.

            PR c++/109300

    gcc/cp/ChangeLog:

            * decl.cc (cp_finish_decl): Diagnose ordinary auto deduction
            with no initializer, instead of asserting.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp1y/var-templ79.C: New test.

[Bug c++/109300] [13 Regression] ICE in cp_finish_decl, at cp/decl.cc:8279 since r13-6380-gd3d205ab44088616

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109300

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

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

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed.