[Bug c++/100372] New: ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[Bug c++/100372] New: ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[mcs at ifam dot uni-hannover.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

            Bug ID: 100372
           Summary: ICE with variadic template template, internal compiler
                    error: in strip_typedefs, at cp/tree.c:1544
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mcs at ifam dot uni-hannover.de
  Target Milestone: ---

Created attachment 50724
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50724&action=edit
File contains: command line, compiler output, preprocessed sources

Minimal testcase with empty main().
Templates compile with 9.1.0 and 10.1.0 and work correctly in production code.

Attachment contains all necessary information in a single text file.
This is my first bug report; I apologize if the formatting is inconvenient.

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.2
           Keywords|                            |ice-on-valid-code
            Summary|ICE with variadic template  |[11/12 Regression] ICE with
                   |template, internal compiler |variadic template template,
                   |error: in strip_typedefs,   |internal compiler error: in
                   |at cp/tree.c:1544           |strip_typedefs, at
                   |                            |cp/tree.c:1544

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-05-03
             Status|UNCONFIRMED                 |NEW
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Thanks for the bug report, confirmed.  Started with r11-7931.

Reduced reproducer:

template <bool> using enable_if_t = int;
template <class> bool has_P_match_v;
template <template <class> class... List> enable_if_t<has_P_match_v<List...>>
a;

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

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

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

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

--- Comment #2 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:061fe8c58ac4d436906a404f7fb46b0a6e0d7b4f

commit r12-894-g061fe8c58ac4d436906a404f7fb46b0a6e0d7b4f
Author: Jason Merrill <jason@redhat.com>
Date:   Tue May 18 17:12:37 2021 -0400

    c++: template template parm pack expansion [PR100372]

    Here we have a pack expansion of a template template parameter pack, of
    which the pattern is a TEMPLATE_DECL, which strip_typedefs doesn't want to
    see.

            PR c++/100372

    gcc/cp/ChangeLog:

            * tree.c (strip_typedefs): Only look at the pattern of a
            TYPE_PACK_EXPANSION if it's a type.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/alias-decl-ttp1.C: New test.

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

--- Comment #3 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:74ad5558d2acddcf4f5e96129ec29dd2f3d47d3a

commit r11-8433-g74ad5558d2acddcf4f5e96129ec29dd2f3d47d3a
Author: Jason Merrill <jason@redhat.com>
Date:   Tue May 18 17:12:37 2021 -0400

    c++: template template parm pack expansion [PR100372]

    Here we have a pack expansion of a template template parameter pack, of
    which the pattern is a TEMPLATE_DECL, which strip_typedefs doesn't want to
    see.

            PR c++/100372

    gcc/cp/ChangeLog:

            * tree.c (strip_typedefs): Only look at the pattern of a
            TYPE_PACK_EXPANSION if it's a type.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/alias-decl-ttp1.C: New test.

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

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

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

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 11.2/12.

[Bug c++/100372] [11/12 Regression] ICE with variadic template template, internal compiler error: in strip_typedefs, at cp/tree.c:1544

[mcs at ifam dot uni-hannover.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100372

--- Comment #5 from Marc C. Steinbach <mcs at ifam dot uni-hannover.de> ---
Thanks for fixing!

I was unable to install any development snapshots,
so I waited for the 11.2.0 release to test my codes.