[J3] finalization and submodule

[Robert Corbett]

I am no longer a member of the committee, so my opinion is only my opinion.  I agree with the argument given that the program shown is standard conformant.  I do not see any difficulty with implementing the behavior implied by the program.  Intel’s implementation is evidence that it can be implemented.

Bob Corbett

> On May 6, 2023, at 10:49 PM, Steven G. Kargl via J3 <j3 at mailman.j3-fortran.org> wrote:
> 
> Is the Fortran code or invalid?  Where are the instructions
> for writing an official interpretation request?
> 
> -- 
> steve
> 
>> On Thu, May 04, 2023 at 11:59:50AM -0700, Steven G. Kargl via J3 wrote:
>> All,
>> 
>> I have a question about finalization and submodules that is
>> sparked by https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97122
>> The code in question is
>> 
>>   MODULE m
>>     IMPLICIT NONE
>>     INTERFACE
>>       MODULE SUBROUTINE other
>>         IMPLICIT NONE
>>       END SUBROUTINE other
>>     END INTERFACE
>>   END MODULE m
>> 
>>   SUBMODULE (m) s
>>     IMPLICIT NONE
>>     TYPE :: t
>>       CONTAINS
>>         FINAL :: p
>>     END TYPE t
>>     CONTAINS
>>       SUBROUTINE p(arg)
>>         TYPE(t), INTENT(INOUT) :: arg
>>       END SUBROUTINE p
>> 
>>       MODULE SUBROUTINE other
>>       END SUBROUTINE other
>>   END SUBMODULE s
>> 
>> According to the bug report, gfortran and nagfor reject the code
>> with an error message of the form
>> 
>>   "Error: pr97122.f90, line 14: Type T has final subroutines
>>    but is not defined in the specification part of a module"
>> 
>> Intel's ifort compiles the code.
>> 
>> Using 22-077r1 (22 Apr 22), I can find
>> 
>>   C791  (R753) A final-subroutine-name shall be the name of a module
>>      procedure with exactly one dummy argument.  That argument shall be
>>      nonoptional and shall be a noncoarray, nonpointer, nonallocatable,
>>      nonpolymorphic variable of the derived type being defined.  All
>>      length type parameters of the dummy argument shall be assumed.
>>      The dummy argument shall not have the INTENT (OUT) or VALUE
>>      attribute.
>> 
>>   3.112.4
>>   module procedure
>>   procedure defined by a module subprogram, or ...
>> 
>>   3.143.3
>>   module subprogram
>>   subprogram that is contained in a module or submodule but is not
>>   an internal subprogram
>> 
>> 
>>   14.2.3 Submodules
>>   ...
>>   3 A submodule may provide implementations for separate module procedures
>>     (15.6.2.5), each of which is declared (15.4.3.2) within that submodule
>>     or one of its ancestors, and declarations and definitions of other
>>    entities that are accessible by host association in its descendants.
>> 
>> AFAIC, 'subroutine p(arg)' meets at the requirement for finalization.
>> I admit that I may have missed something in chasing 'module procedure'
>> through 22-007r1.
>> 
>> So, the question are
>> 'Are gfortran and nagfor correct in rejecting the code?'
>> 'Does have Intel's ifort have bug?'
>> 'Does the Fortran standard need be refined to explicitly
>>  state that derived type with a final statement can only
>>  appear in the specification part of a module?'
>> 
>> -- 
>> Steve
> 
> 
> 
> -- 
> Steve