[Bug fortran/55172] New: ICE on invalid: gfc_variable_attr(): Bad array reference

[Bug fortran/55172] New: ICE on invalid: gfc_variable_attr(): Bad array reference

[abensonca at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

             Bug #: 55172
           Summary: ICE on invalid: gfc_variable_attr(): Bad array
                    reference
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: abensonca@gmail.com


The following test case produces and ICE with gfortran 4.8 (r193051):

module gn
  type :: ncb
  end type ncb
  type, public :: tn
     class(ncb), allocatable, dimension(:) :: cb
  end type tn
contains
  integer function name(self)
    implicit none
    class (tn), intent(in) :: self
    select type (component => self%cb(i))
    end select
  end function name
end module gn

$ gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/home/abenson/Galacticus/Tools/libexec/gcc/x86_64-unknown-
linux-gnu/4.8.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --
prefix=/home/abenson/Galacticus/Tools --enable-languages=c,c++,fortran --
disable-multilib --with-gmp=/home/abenson/Galacticus/Tools
Thread model: posix
gcc version 4.8.0 20121031 (experimental) (GCC) 

$ gfortran -c bug4.F90 -o bug4.o
bug4.F90:14.13:

end module gn
             1   
Internal Error at (1):
gfc_variable_attr(): Bad array reference


The code is invalid because the "name" function contains "implicit none" but 
the variable "i" used in:

    select type (component => self%cb(i))

is not explicitly defined. If I remove the "implicit none" or explicitly 
define "i" the ICE goes away.


(Reported by Janus at http://gcc.gnu.org/ml/fortran/2012-11/msg00005.html):
With 4.7 the ICE also occurs, but only after the correct error message:

    select type (component => self%cb(i))
                                       1
Error: Symbol 'i' at (1) has no IMPLICIT type

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-11-02
            Summary|[OOP] ICE on invalid:       |[4.7/4.8 Regression] [OOP]
                   |gfc_variable_attr(): Bad    |ICE on invalid:
                   |array reference             |gfc_variable_attr(): Bad
                   |                            |array reference
     Ever Confirmed|0                           |1

--- Comment #1 from janus at gcc dot gnu.org 2012-11-02 11:07:33 UTC ---
(In reply to comment #0)
> (Reported by Janus at http://gcc.gnu.org/ml/fortran/2012-11/msg00005.html):
> With 4.7 the ICE also occurs, but only after the correct error message:
> 
>     select type (component => self%cb(i))
>                                        1
> Error: Symbol 'i' at (1) has no IMPLICIT type


Yes, therefore it's a regression in 4.7 (ICE after error) and 4.8 (ICE only).


4.6 of course rejects it ('cleanly') with:

     class(ncb), allocatable, dimension(:) :: cb
                                                1
Fatal Error: Polymorphic array at (1) not yet supported



(Side note: The 'fatal' seems a bit strong here, but that was probably used to
suppress further error messages.)

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

janus at gcc dot gnu.org changed:

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

--- Comment #2 from janus at gcc dot gnu.org 2012-11-02 12:09:50 UTC ---
I suspect the 4.8-problem of having only the ICE without a prior error message
might be due to this commit:

http://gcc.gnu.org/viewcvs?view=revision&revision=187192

I think the function 'copy_ts_from_selector_to_associate' comes too early
(namely during parsing). It tries to resolve the target expr, which should
rather wait until resolution stage!?!

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.7.3

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

Paul Thomas <pault at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot       |pault at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #3 from Paul Thomas <pault at gcc dot gnu.org> 2013-01-02 12:34:35 UTC ---
(In reply to comment #2)
> I suspect the 4.8-problem of having only the ICE without a prior error message
> might be due to this commit:
> 
> http://gcc.gnu.org/viewcvs?view=revision&revision=187192
> 
> I think the function 'copy_ts_from_selector_to_associate' comes too early
> (namely during parsing). It tries to resolve the target expr, which should
> rather wait until resolution stage!?!

This is partially correct.  Unfortunately, the selector expression comes from
the parser with the ar->type == AR_UNKNOWN and it was this that
gfc_resolve_expr was putting right.  As long as all the variables were declared
or had implicit types, all was well.

Th is fixed by removing the call to gfc_resolve_expr and adding explicit code,
copied from resolve_array_ref, to set the correct type.  It is also
necessary/advisable to add a call to resolve the selector expression in
resolve_select_type.

I will submit a patch later today.

Cheers

Paul

PS If the index 'i' is declared, wrong code results as in pr54990.

[Bug fortran/55172] [4.7/4.8 Regression] [OOP] ICE on invalid: gfc_variable_attr(): Bad array reference

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

--- Comment #4 from Paul Thomas <pault at gcc dot gnu.org> 2013-01-04 20:50:23 UTC ---
Author: pault
Date: Fri Jan  4 20:50:15 2013
New Revision: 194916

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=194916
Log:
2013-01-04  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/55172
    * match.c (copy_ts_from_selector_to_associate): Remove call to
    gfc_resolve_expr and replace it with explicit setting of the
    array reference type.
    * resolve.c (resolve_select_type): It is an error if the
    selector is coindexed.

2013-01-04  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/55172
    * gfortran.dg/select_type_31.f03: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/select_type_31.f03
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/match.c
    trunk/gcc/fortran/resolve.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/55172] [4.7 only] [OOP] gfc_variable_attr(): Bad array reference in SELECT TYPE

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

Paul Thomas <pault at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|4.8.0                       |4.7.3
         AssignedTo|pault at gcc dot gnu.org    |unassigned at gcc dot
                   |                            |gnu.org
            Summary|[4.7/4.8 Regression] [OOP]  |[4.7 only] [OOP]
                   |ICE on invalid:             |gfc_variable_attr(): Bad
                   |gfc_variable_attr(): Bad    |array reference in SELECT
                   |array reference             |TYPE

--- Comment #5 from Paul Thomas <pault at gcc dot gnu.org> 2013-01-05 07:52:31 UTC ---
I tried the best I could with 4.7 but there are quite significant divergences
with trunk, both around and downstream from the patch.  The best that I could
manage was:

/svn/gcc-4_7-branch/gcc/testsuite/gfortran.dg/select_type_31.f03:16.4:

    select type (component => self%cb(i) ! { dg-error "has no IMPLICIT type" }
    1
Error: Unclassifiable statement at (1)
/svn/gcc-4_7-branch/gcc/testsuite/gfortran.dg/select_type_31.f03:17.7:

    end select
       1
Error: Expecting END FUNCTION statement at (1)

which is more opaque than the correct error followed by the internal error!

I decided, therefore, to leave the PR as 4.7 only and have unassigned myself.

In addition, I think that to call it a regression is incorrect since
polymorphic arrays were unavailable in 4.6!  I have therefore removed
regression from the title.

I might be persuaded to return to this, once 4.8 is released.

Paul

[Bug fortran/55172] [4.7 Regression] [OOP] gfc_variable_attr(): Bad array reference in SELECT TYPE

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.7.3                       |4.7.4

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-11 07:59:29 UTC ---
GCC 4.7.3 is being released, adjusting target milestone.

[Bug fortran/55172] [4.7 Regression] [OOP] gfc_variable_attr(): Bad array reference in SELECT TYPE

[pault at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55172

Paul Thomas <pault at gcc dot gnu.org> changed:

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

--- Comment #7 from Paul Thomas <pault at gcc dot gnu.org> ---
I think that it is best to leave this unfixed for 4.7 - see comment #5

I have therefore marked the PR as resolved.

Thanks for the report

Paul