[Patch, Fortran] PR 41873 & 41556

[Janus Weil <janus at gcc dot gnu dot org>]

Hi all,

here is a patch for PR 41873, which also fixes a part of PR 41556. The
problem was that a check, which prevents abstract interfaces from
being called, falsely triggered an error for deferred type-bound
procedures with abstract interface.

My solution to this may be a bit hackish, but it works very good in
practice: To distinguish both cases I simply check certain fields,
which are always set for the TBP case, but not for plain abstract
interfaces.

When working on this PR, I also noticed that the check for calling
abstract subroutines was missing completely (only functions were
checked), so I also added this (again distinguishing TBPs).

The patch regtests without failures on x86_64-unknown-linux-gnu. Ok for trunk?

Cheers,
Janus


2009-11-04  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/41556
	PR fortran/41873
	* resolve.c (resolve_function,resolve_call): Prevent abstract interfaces
	from being called, but allow deferred type-bound procedures with
	abstract interface.


2009-11-04  Janus Weil  <janus@gcc.gnu.org>

	PR fortran/41556
	PR fortran/41873
	* gfortran.dg/interface_abstract_4.f90: New test.

Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 153911)
+++ gcc/fortran/resolve.c	(working copy)
@@ -2526,7 +2526,9 @@ resolve_function (gfc_expr *expr)
       return FAILURE;
     }
 
-  if (sym && sym->attr.abstract)
+  /* If this ia a deferred TBP with an abstract interface (which may
+     of course be referenced), expr->value.function.name will be set.  */
+  if (sym && sym->attr.abstract && !expr->value.function.name)
     {
       gfc_error ("ABSTRACT INTERFACE '%s' must not be referenced at %L",
 		 sym->name, &expr->where);
@@ -3138,6 +3140,15 @@ resolve_call (gfc_code *c)
 	}
     }
 
+  /* If this ia a deferred TBP with an abstract interface
+     (which may of course be referenced), c->expr1 will be set.  */
+  if (csym && csym->attr.abstract && !c->expr1)
+    {
+      gfc_error ("ABSTRACT INTERFACE '%s' must not be referenced at %L",
+		 csym->name, &c->loc);
+      return FAILURE;
+    }
+
   /* Subroutines without the RECURSIVE attribution are not allowed to
    * call themselves.  */
   if (csym && is_illegal_recursion (csym, gfc_current_ns))

Attachment: interface_abstract_4.f90
Description: Binary data