[Bug fortran/105800] New: Segfault deallocating a class, dimension(:) array

[Bug fortran/105800] New: Segfault deallocating a class, dimension(:) array

[mscfd at gmx dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105800

            Bug ID: 105800
           Summary: Segfault deallocating a class, dimension(:) array
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mscfd at gmx dot net
  Target Milestone: ---

Created attachment 53062
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53062&action=edit
test class_dealloc.f90

Creating an array in a function with return value "type(t), dimension(:)", and
assigning it to a "class(t), dimension(:)" variable eventually leads to a
segfault when deallocating the array. See attached test.

valgrind shows invalid read due to uninitialised value (presumably the
type-descriptor of the "class(t), dimension(:)" variable is not completely
initialised). If the "type(t)" is changed to "class(t)" in the create function,
then it works fine, without any complains from valgrind.

[Bug fortran/105800] Segfault deallocating a class, dimension(:) array

[mscfd at gmx dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105800

--- Comment #1 from martin <mscfd at gmx dot net> ---
Created attachment 54856
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54856&action=edit
fixed testcase class_dealloc.f90

As I just see, the first attachment does not show the bug as return value "a"
of function create is declared as "class(t), dimension(:), pointer". And as
described in the initial report, with class instead of type, there is no error.

The fixed attachment declares "a" as "type(t), dimension(:), pointer". This
shows the described error. It is still present in the current 13 development
branch.

[Bug fortran/105800] Segfault deallocating a class, dimension(:) array

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105800

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-04-14

--- Comment #2 from anlauf at gcc dot gnu.org ---
(In reply to martin from comment #1)
> The fixed attachment declares "a" as "type(t), dimension(:), pointer". This
> shows the described error. It is still present in the current 13 development
> branch.

It is the pointer assignment in subroutine init

    self%x => a

that fails.