Re: [Patch, fortran] PR18578, PR18579, PR20857 and PR20885 - Constraints on INTENT(OUT and INOUT)

[Paul Thomas <paulthomas2 at wanadoo dot fr>]

Paul:

Are you OK with this minimalist version?  All the probing of undefined 
variables has gone.  All that remains is the test for the actual being 
definable.

This patch implements the obvious constraint on the use of INTENT(OUT 
and INOUT).  ie: that the actual argument should be a variable 
("definable" in the standard).  The patch is straightforward.

Regtested on Athlon/FC3.  OK for 4.2 and 4.1?

Paul

2006-01-29  Paul Thomas  <pault@gcc.gnu.org>

  PR fortran/18578
  PR fortran/18579
  PR fortran/20857
  PR fortran/20885
  * interface.c (compare_actual_formal): Error for INTENT(OUT or INOUT)
  if actual argument is not a variable.

2006-01-29  Paul Thomas  <pault@gcc.gnu.org>

  PR fortran/18578
  PR fortran/18579
  PR fortran/20857
  PR fortran/20885
  * gfortran.dg/intent_out_1.f90: New test.

Index: gcc/fortran/interface.c
===================================================================
*** gcc/fortran/interface.c	(revision 110364)
--- gcc/fortran/interface.c	(working copy)
*************** compare_actual_formal (gfc_actual_arglis
*** 1273,1278 ****
--- 1273,1288 ----
  	  return 0;
  	}
  
+       /* Check intent = OUT/INOUT for definable actual argument.  */
+       if (a->expr->expr_type != EXPR_VARIABLE
+ 	     && (f->sym->attr.intent == INTENT_OUT
+ 		   || f->sym->attr.intent == INTENT_INOUT))
+ 	{
+ 	  gfc_error ("Actual argument at %L must be definable to "
+ 		     "match dummy INTENT = OUT/INOUT", &a->expr->where);
+           return 0;
+         }
+ 
      match:
        if (a == actual)
  	na = i;

! { dg-do compile }
! Tests the fix for PRs 18578, 18579 and their repeats 20857 and 20885.
! Contributed by Paul Thomas  <pault@gcc@gnu.org>
  real, parameter :: a =42.0
  real :: b
  call foo(b + 2.0)    ! { dg-error "must be definable" }
  call foo(a)          ! { dg-error "must be definable" }
  call bar(b + 2.0)    ! { dg-error "must be definable" }
  call bar(a)          ! { dg-error "must be definable" }
contains
  subroutine foo(a)
    real, intent(out) :: a
    a = 0.0
  end subroutine foo
  subroutine bar(a)
    real, intent(INout) :: a
    a = 0.0
  end subroutine bar
end