[Bug c++/106024] New: ICE on missing template keyword in template method call in pack expansion

[Bug c++/106024] New: ICE on missing template keyword in template method call in pack expansion

[kacper.slominski72 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

            Bug ID: 106024
           Summary: ICE on missing template keyword in template method
                    call in pack expansion
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kacper.slominski72 at gmail dot com
  Target Milestone: ---

Created attachment 53162
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53162&action=edit
-freport-bug output

The following code, when compiled with -std=c++20, causes an ICE. Attached is
the file produced by -freport-bug.

auto foo() {
        return [&] <auto...args> () {
                return [] (auto...) {} (
                        [] <auto T> (auto...) {
                                return 1;
                        }.operator()<args>(args...)...
                );
        }.operator()<1, 2, 3>();
}

I'm tempted to say this is ICE-on-invalid since adding the missing "template"
keyword before "operator()" gets rid of it, but I'm not 100% sure.

[Bug c++/106024] ICE on missing template keyword in template method call in pack expansion

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Note clang rejects it with:

clang++ pr106033.C -c -std=c++2a
pr106033.C:6:27: error: expected ')'
   }.operator()<args>(args...)...
                          ^
pr106033.C:6:22: note: to match this '('
   }.operator()<args>(args...)...
                     ^
pr106033.C:6:6: error: missing 'template' keyword prior to dependent template
name 'operator()'
   }.operator()<args>(args...)...
     ^
pr106033.C:8:4: note: in instantiation of function template specialization
'foo()::(anonymous class)::operator()<1, 2, 3>' requested here
 }.operator()<1, 2, 3>();
   ^
2 errors generated.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE on missing template     |[11/12/13 Regression] ICE
                   |keyword in template method  |on missing template keyword
                   |call in pack expansion      |in template method call in
                   |                            |pack expansion
   Target Milestone|---                         |11.4
      Known to work|                            |10.3.0
      Known to fail|                            |11.1.0

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |10.3.0
             Status|UNCONFIRMED                 |NEW
            Summary|ICE on missing template     |[11/12/13 Regression] ICE
                   |keyword in template method  |on missing template keyword
                   |call in pack expansion      |in template method call in
                   |                            |pack expansion
   Last reconfirmed|                            |2022-06-20
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, a regression from 10.x.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

Jason Merrill <jason at gcc dot gnu.org> changed:

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

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Testcase with only one lambda:

template <class... Ts> void sink(Ts &&...);
template <auto... args> void f()
{
  sink ([] <auto T> (auto...) { return 1; }
        .operator()<args>(args...)...);
}

int main()
{
  f<1,2,3>();
}

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:07ac550393d00fcadcee21b44abee6bb30c93949

commit r13-1390-g07ac550393d00fcadcee21b44abee6bb30c93949
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jun 23 23:14:35 2022 -0400

    c++: dependent generic lambda template-id [PR106024]

    We were wrongly looking up the generic lambda op() in a dependent scope,
and
    then trying to look up its instantiation at substitution time, but lambdas
    aren't instantiated, so we crashed.  The fix is to not look into dependent
    class scopes.

    But this created trouble with wrongly trying to use a template from the
    enclosing scope when we aren't actually looking at a
template-argument-list,
    in template/lookup18.C, so let's avoid that.

            PR c++/106024

    gcc/cp/ChangeLog:

            * parser.cc (missing_template_diag): Factor out...
            (cp_parser_id_expression): ...from here.
            (cp_parser_lookup_name): Don't look in dependent object_type.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/lambda-generic10.C: New test.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:c17206709f94331e81443e2bdcf135a6ab7428ce

commit r12-8533-gc17206709f94331e81443e2bdcf135a6ab7428ce
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jun 23 23:14:35 2022 -0400

    c++: dependent generic lambda template-id [PR106024]

    We were wrongly looking up the generic lambda op() in a dependent scope,
and
    then trying to look up its instantiation at substitution time, but lambdas
    aren't instantiated, so we crashed.  The fix is to not look into dependent
    class scopes.

    But this created trouble with wrongly trying to use a template from the
    enclosing scope when we aren't actually looking at a
template-argument-list,
    in template/lookup18.C, so let's avoid that.

            PR c++/106024

    gcc/cp/ChangeLog:

            * parser.cc (missing_template_diag): Factor out...
            (cp_parser_id_expression): ...from here.
            (cp_parser_lookup_name): Don't look in dependent object_type.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/lambda-generic10.C: New test.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:e748398b3ef6412ef35b85ef6b0893809aeb49cd

commit r12-8537-ge748398b3ef6412ef35b85ef6b0893809aeb49cd
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jul 1 11:02:54 2022 -0400

    c++: simpler fix for PR106024

    Actually, for release branches let's just avoid the lookup for the lambdas
    that are the problematic case and only make the bigger change on trunk.

            PR c++/106024

    gcc/cp/ChangeLog:

            * parser.cc (cp_parser_lookup_name): Limit previous change to
            lambdas.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:252e9dfee9b1d01e0e44773ad83e0e44f3650945

commit r11-10100-g252e9dfee9b1d01e0e44773ad83e0e44f3650945
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Jun 23 23:14:35 2022 -0400

    c++: dependent generic lambda template-id [PR106024]

    We were wrongly looking up the generic lambda op() in a dependent scope,
and
    then trying to look up its instantiation at substitution time, but lambdas
    aren't instantiated, so we crashed.  The fix is to not look into dependent
    lambda scopes.

            PR c++/106024

    gcc/cp/ChangeLog:

            * parser.c (cp_parser_lookup_name): Don't look in dependent lambda.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/lambda-generic10.C: New test.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

Jason Merrill <jason at gcc dot gnu.org> changed:

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

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 11.4/12.2/13.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:656c0212909bc91b1025aa12774d981adb531b4c

commit r13-1516-g656c0212909bc91b1025aa12774d981adb531b4c
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Jul 5 17:05:47 2022 -0400

    c++: dependent conversion operator lookup [PR106179]

    This testcase demonstrates that my assumption that we would only be
    interested in a class template lookup if the template-id is followed by ::
    was wrong.

            PR c++/106179
            PR c++/106024

    gcc/cp/ChangeLog:

            * parser.cc (cp_parser_lookup_name): Remove :: requirement
            for using unqualified lookup result.

    gcc/testsuite/ChangeLog:

            * g++.dg/template/operator16.C: New test.

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amir.ahmed.ansari at outlook dot c
                   |                            |om

--- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 106351 has been marked as a duplicate of this bug. ***

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |johelegp at gmail dot com

--- Comment #11 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 102931 has been marked as a duplicate of this bug. ***

[Bug c++/106024] [11/12/13 Regression] ICE on missing template keyword in template method call in pack expansion

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106024

--- Comment #12 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Simon Martin <simartin@gcc.gnu.org>:

https://gcc.gnu.org/g:88c9b96b2800ddb7a499bd10abaa9441a471d5fe

commit r15-847-g88c9b96b2800ddb7a499bd10abaa9441a471d5fe
Author: Simon Martin <simartin@gcc.gnu.org>
Date:   Fri May 24 10:56:36 2024 +0200

    Add testcase for PR c++/105229: ICE in lookup_template_class_1

    The test case in PR c++/105229 has been fixed since 11.4 (via
    PR c++/106024) - the attached patch simply adds the case to
    the test suite.

    Successfully tested on x86_64-pc-linux-gnu.

            PR c++/105229

    gcc/testsuite/ChangeLog:

            * g++.dg/parse/crash72.C: New test.