[Bug fortran/96469] New: Compile-time check for change in DO variable in contained procedures

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96469

            Bug ID: 96469
           Summary: Compile-time check for change in DO variable in
                    contained procedures
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tkoenig at gcc dot gnu.org
  Target Milestone: ---

What's checked at runtime in do_check_4.f90

PROGRAM test
  IMPLICIT NONE
  INTEGER :: i
  DO i=1,100
    CALL do_something()
  ENDDO
CONTAINS
 SUBROUTINE do_something()
 IMPLICIT NONE
   DO i=1,10
   ENDDO
 END SUBROUTINE do_something
END PROGRAM test

can also be tested at compile-time, with an error issued.

As a matter of fact, I have a patch regtesting right now, I just wanted
put this into bugzilla as an anchor.