[Bug fortran/109846] New: [rejects valid] Pointer-valued function reference rejected as actual argument

[Bug fortran/109846] New: [rejects valid] Pointer-valued function reference rejected as actual argument

[neil.n.carlson at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

            Bug ID: 109846
           Summary: [rejects valid] Pointer-valued function reference
                    rejected as actual argument
           Product: gcc
           Version: 13.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: neil.n.carlson at gmail dot com
  Target Milestone: ---

Gfortran rejects the following example.

module foo
  type :: parameter_list
  contains
    procedure :: sublist
  end type
contains
  function sublist(this) result(slist)
    class(parameter_list), intent(inout) :: this
    class(parameter_list), pointer :: slist
    allocate(slist)
  end function
end module

program example
  use foo
  type(parameter_list) :: plist
  call sub(plist%sublist())
contains
  subroutine sub(plist)
    type(parameter_list), intent(inout) :: plist
  end subroutine
end program

With this error:

   17 |   call sub(plist%sublist())
      |           1
Error: ‘sublist’ in variable definition context (actual argument to INTENT =
OUT/INOUT) at (1) is not a variable

It is accepted by both Intel OneAPI and NAG compilers. The sublist function
returns
a polymorphic pointer, which seems to be the source of the error. If it is
modified
to return a non-polymorphic pointer the example compiles without error.
Alternatively,
if the dummy argument intent is changed to intent(in) it also compiles without
error.

It is valid for a class(parameter_list) variable to be the actual argument for
a
type(parameter_list), intent(inout) dummy argument. So in light of 9.2/C902
(2018)
I think this is a gfortran bug.

[Bug fortran/109846] [rejects valid] Pointer-valued function reference rejected as actual argument

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #1 from kargl at gcc dot gnu.org ---
Confirmed.

Workaround seems to be to not use a RESULT variable.
This change seems to work

  function sublist(this)
    class(parameter_list), intent(inout) :: this
    class(parameter_list), pointer :: sublist
    allocate(sublist)
  end function

[Bug fortran/109846] [rejects valid] Pointer-valued function reference rejected as actual argument

[neil.n.carlson at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #2 from Neil Carlson <neil.n.carlson at gmail dot com> ---
Amusing! I have a regression in 13.1 (which I need to create a reproducer for)
where the workaround for a segfault is to use a RESULT variable -- just the
opposite :-)

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |rejects-valid
                 CC|                            |anlauf at gcc dot gnu.org
   Last reconfirmed|                            |2023-05-14
            Summary|[rejects valid]             |Pointer-valued function
                   |Pointer-valued function     |reference rejected as
                   |reference rejected as       |actual argument
                   |actual argument             |

--- Comment #3 from anlauf at gcc dot gnu.org ---
Tentative patch to fix the CLASS pointer case:

diff --git a/gcc/fortran/expr.cc b/gcc/fortran/expr.cc
index d91722e6ac6..1955c8471a4 100644
--- a/gcc/fortran/expr.cc
+++ b/gcc/fortran/expr.cc
@@ -6256,7 +6265,7 @@ gfc_check_vardef_context (gfc_expr* e, bool pointer, bool
alloc_obj,
       && !(sym->attr.flavor == FL_PROCEDURE && sym == sym->result)
       && !(sym->attr.flavor == FL_PROCEDURE && sym->attr.proc_pointer)
       && !(sym->attr.flavor == FL_PROCEDURE
-          && sym->attr.function && sym->attr.pointer))
+          && sym->attr.function && attr.pointer))
     {
       if (context)
        gfc_error ("%qs in variable definition context (%s) at %L is not"

Regtesting now.

Another workaround is to not specify an INTENT for dummy argument plist, i.e.

   type(parameter_list) :: plist

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

anlauf at gcc dot gnu.org changed:

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

--- Comment #4 from anlauf at gcc dot gnu.org ---
Looks like an extension of pr100218.

Regtested ok.  Taking.

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #5 from anlauf at gcc dot gnu.org ---
Submitted: https://gcc.gnu.org/pipermail/fortran/2023-May/059297.html

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:fa0569e90efe8a5cb895a3f50dd502f849940828

commit r14-863-gfa0569e90efe8a5cb895a3f50dd502f849940828
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Sun May 14 21:53:51 2023 +0200

    Fortran: CLASS pointer function result in variable definition context
[PR109846]

    gcc/fortran/ChangeLog:

            PR fortran/109846
            * expr.cc (gfc_check_vardef_context): Check appropriate pointer
            attribute for CLASS vs. non-CLASS function result in variable
            definition context.

    gcc/testsuite/ChangeLog:

            PR fortran/109846
            * gfortran.dg/ptr-func-5.f90: New test.

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Harald Anlauf
<anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:f48c546902802cf640c4f2802543acfdc702404f

commit r13-7354-gf48c546902802cf640c4f2802543acfdc702404f
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Sun May 14 21:53:51 2023 +0200

    Fortran: CLASS pointer function result in variable definition context
[PR109846]

    gcc/fortran/ChangeLog:

            PR fortran/109846
            * expr.cc (gfc_check_vardef_context): Check appropriate pointer
            attribute for CLASS vs. non-CLASS function result in variable
            definition context.

    gcc/testsuite/ChangeLog:

            PR fortran/109846
            * gfortran.dg/ptr-func-5.f90: New test.

    (cherry picked from commit fa0569e90efe8a5cb895a3f50dd502f849940828)

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Harald Anlauf
<anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:7259fd5bd4c922f396465c9cfec2ec342969f9a9

commit r12-9628-g7259fd5bd4c922f396465c9cfec2ec342969f9a9
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Sun May 14 21:53:51 2023 +0200

    Fortran: CLASS pointer function result in variable definition context
[PR109846]

    gcc/fortran/ChangeLog:

            PR fortran/109846
            * expr.cc (gfc_check_vardef_context): Check appropriate pointer
            attribute for CLASS vs. non-CLASS function result in variable
            definition context.

    gcc/testsuite/ChangeLog:

            PR fortran/109846
            * gfortran.dg/ptr-func-5.f90: New test.

    (cherry picked from commit fa0569e90efe8a5cb895a3f50dd502f849940828)

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Harald Anlauf
<anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:fb47733938b352c6d84ef342fc11d2bd478d1218

commit r11-10795-gfb47733938b352c6d84ef342fc11d2bd478d1218
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Sun May 14 21:53:51 2023 +0200

    Fortran: CLASS pointer function result in variable definition context
[PR109846]

    gcc/fortran/ChangeLog:

            PR fortran/109846
            * expr.c (gfc_check_vardef_context): Check appropriate pointer
            attribute for CLASS vs. non-CLASS function result in variable
            definition context.

    gcc/testsuite/ChangeLog:

            PR fortran/109846
            * gfortran.dg/ptr-func-5.f90: New test.

    (cherry picked from commit fa0569e90efe8a5cb895a3f50dd502f849940828)

[Bug fortran/109846] Pointer-valued function reference rejected as actual argument

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109846

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
   Target Milestone|---                         |11.4
             Status|ASSIGNED                    |RESOLVED

--- Comment #10 from anlauf at gcc dot gnu.org ---
Fixed on mainline for gcc-14, and on release branches down to 11.