[Bug fortran/50541] New: gfortran should not accept a pointer as a generic-name (r178939)

[Bug fortran/50541] New: gfortran should not accept a pointer as a generic-name (r178939)

[zeccav at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

             Bug #: 50541
           Summary: gfortran should not accept a pointer as a generic-name
                      (r178939)
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zeccav@gmail.com


! gfortran should not accept a pointer as a generic-name   (r178939)
      pointer s    ! gfortran should complain here
      interface s  ! or here
       function f()
! this is the right place to specify the pointer attribute
        pointer f
       end function
      end interface
      end

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-09-27
                 CC|                            |janus at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |janus at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from janus at gcc dot gnu.org 2011-09-27 17:36:10 UTC ---
This one is trivial:

Index: gcc/fortran/symbol.c
===================================================================
--- gcc/fortran/symbol.c        (revision 179255)
+++ gcc/fortran/symbol.c        (working copy)
@@ -504,6 +504,7 @@ check_conflict (symbol_attribute *attr, const char
   conf (dummy, result);
   conf (entry, result);
   conf (generic, result);
+  conf (generic, pointer);

   conf (function, subroutine);

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

--- Comment #2 from janus at gcc dot gnu.org 2011-09-28 11:14:16 UTC ---
(In reply to comment #1)
> This one is trivial:

Unfortunately this causes one testsuite regression:

FAIL: gfortran.dg/func_derived_4.f90  -O0  (test for excess errors)


Reduced test case:


module class_field
  implicit none
  interface msh
    module procedure msh
  end interface
contains
  function msh()
    integer, pointer :: msh
  end function
end module


What is special about this, is that the generic and the specific procedure
share the same name. I think the problem is that we only have one symbol for
both, which triggers the conflict.

Possible solutions:
 * (quick'n'dirty) refine the check to only raise a conflict if there is no
specific procedure with the same name 
 * (cleaner but harder) introduce separate symbols for generics (in a separate
symtree), which might also solve our problems with 'constructors' (cf. PR
39427)

For specifics and generics with the same name, see also PR 42418.

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

Tobias Burnus <burnus at gcc dot gnu.org> changed:

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

--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-09-28 15:02:02 UTC ---
(In reply to comment #2)
> What is special about this, is that the generic and the specific procedure
> share the same name. I think the problem is that we only have one symbol for
> both, which triggers the conflict.

I think one could solve this at parse time. When parsing POINTER and
sym->attr.generic and gfc_ns_current->proc_name != sym, we set the attribute to
an interface block. Ditto when parsing "INTERFACE <generic_name>": If one has
already sym->attr.pointer, it is a bug. That should work without further
changes.

Regarding the constructor patch (PR 39427): At least with my current draft
patch does not use a different symbol.

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[zeccav at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

Vittorio Zecca <zeccav at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|4.7.0                       |4.8.0

--- Comment #4 from Vittorio Zecca <zeccav at gmail dot com> 2013-04-16 08:53:16 UTC ---
I still have the same bug on gfortran 4.8.0.

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

--- Comment #5 from Vittorio Zecca <zeccav at gmail dot com> ---
Bug still there in 5.2.0

[Bug fortran/50541] gfortran should not accept a pointer as a generic-name (r178939)

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50541

--- Comment #7 from Vittorio Zecca <zeccav at gmail dot com> ---
The NAG nagfor and Intel ifort detect the issue.

gfortran -S gfbug81.f

[vitti f95]$nagfor -S gfbug81.f
NAG Fortran Compiler Release 7.0(Yurakucho) Build 7042
Error: gfbug81.f, line 4: Multiply defined symbol S
       detected at INTERFACE@S
Warning: gfbug81.f, line 10: Unused local variable S

[NAG Fortran Compiler pass 1 error termination, 1 error, 1 warning]
[vitti f95]$ifort -S gfbug81.f
gfbug81.f(3): error #6449: This name has already been used as a generic
procedure name   [S]
      pointer s    ! gfortran should complain here
--------------^
compilation aborted for gfbug81.f (code 1)