[Bug c++/114377] New: GCC crashes on an example of CTAD for alias templates

[Bug c++/114377] New: GCC crashes on an example of CTAD for alias templates

[hokein.wu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

            Bug ID: 114377
           Summary: GCC crashes on an example of CTAD for alias templates
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hokein.wu at gmail dot com
  Target Milestone: ---

(This was spotted when I tried to fix a clang crash.)

gcc trunk crashes on the following code, https://godbolt.org/z/x8E95sfTo


```
template <template <typename> typename Iterator>
struct K {};

template <typename C, typename IteratorPolicy>
class Foo {};

template <typename C, template<typename> typename TTP>
using Bar = Foo<C, K<TTP>>;

void s() {
    Bar(1);
}
```

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
      Known to fail|                            |13.2.0, 14.0
             Status|UNCONFIRMED                 |NEW
      Known to work|                            |12.3.0
   Target Milestone|---                         |13.3
     Ever confirmed|0                           |1
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=105841
            Summary|GCC crashes on an example   |[13/14 Regression] GCC
                   |of CTAD for alias templates |crashes on an example of
                   |                            |CTAD for alias templates
   Last reconfirmed|                            |2024-03-18
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
The ICE started with r13-6555-g9e6170098d5e77.

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

Jeffrey A. Law <law at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1
                 CC|                            |law at gcc dot gnu.org

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P1                          |P2
            Version|unknown                     |13.2.1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
P2, we released with this bug.

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
*** Bug 114497 has been marked as a duplicate of this bug. ***

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Patch from Centurion:
https://gcc.gnu.org/pipermail/gcc-patches/2024-March/648338.html

[Bug c++/114377] [13/14 Regression] GCC crashes on an example of CTAD for alias templates

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

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

https://gcc.gnu.org/g:801e82acd6b4f0cf863529875947e394899ea7b9

commit r14-9795-g801e82acd6b4f0cf863529875947e394899ea7b9
Author: centurion <centurion009@proton.me>
Date:   Wed Mar 27 18:36:37 2024 +0000

    c++: alias CTAD and template template parm [PR114377]

    To match all the other places that pull a _TEMPLATE_PARM out of a
    _DECL (get_template_parm_index, etc.).

    This change is too small to be legally significant for copyright.

            PR c++/114377

    gcc/cp/ChangeLog:

            * pt.cc (find_template_parameter_info::found): Use TREE_TYPE for
            TEMPLATE_DECL instead of DECL_INITIAL.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/class-deduction-alias19.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>

[Bug c++/114377] [13 Regression] GCC crashes on an example of CTAD for alias templates

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:60e1e13f458f1fcfb05a30ace57fa682461e2732

commit r13-8669-g60e1e13f458f1fcfb05a30ace57fa682461e2732
Author: centurion <centurion009@proton.me>
Date:   Wed Mar 27 18:36:37 2024 +0000

    c++: alias CTAD and template template parm [PR114377]

    To match all the other places that pull a _TEMPLATE_PARM out of a
    _DECL (get_template_parm_index, etc.).

    This change is too small to be legally significant for copyright.

            PR c++/114377

    gcc/cp/ChangeLog:

            * pt.cc (find_template_parameter_info::found): Use TREE_TYPE for
            TEMPLATE_DECL instead of DECL_INITIAL.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/class-deduction-alias19.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>
    (cherry picked from commit 801e82acd6b4f0cf863529875947e394899ea7b9)

[Bug c++/114377] [13 Regression] GCC crashes on an example of CTAD for alias templates

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114377

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

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

--- Comment #7 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 13.3/14.