From patchwork Thu Sep  2 21:44:01 2010
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Subject: fortran/45495 -- optional dummy args cannot not be in restricted
 expressions
Date: Thu, 02 Sep 2010 11:44:01 -0000
From: Steve Kargl <sgk@troutmask.apl.washington.edu>
X-Patchwork-Id: 63560
Message-Id: <20100902214401.GA64816@troutmask.apl.washington.edu>
To: fortran@gcc.gnu.org, gcc-patches@gcc.gnu.org

A specification expression is an expression with limitations
that make it suitable for use in specifications such as length
type parameters (C501) and array bounds (R512, R513).

R729  specification-expr          is   scalar-int-expr

C710  (R729) The scalar-int-expr shall be a restricted expression.

A restricted expression is an expression in which each operation
is intrinsic and each primary is
...
  (2)  An object designator with a base object that is a dummy
       argument that has neither the OPTIONAL nor the INTENT(OUT)
       attribute,

The attach patch enforces the above restriction.  It has been
built and regression tested on x86_64-*-freebsd.  OK for trunk?


2010-09-02  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/45495
	* gfortran.dg/dummy_optional_arg.f90: New test.

2010-09-02  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/45495
	* fortran/expr.c (check_inquiry): Optional dummy argument are not
	permitted in a restricted expression.


Index: gcc/testsuite/gfortran.dg/dummy_optional_arg.f90
===================================================================
--- gcc/testsuite/gfortran.dg/dummy_optional_arg.f90	(revision 0)
+++ gcc/testsuite/gfortran.dg/dummy_optional_arg.f90	(revision 0)
@@ -0,0 +1,11 @@
+! { dg-do compile }
+! PR fortran/45495
+!
+! Code originally submitted by Philip Mason <pmason at ricardo dot com>
+!
+function jack(aa)
+   character(len=*), intent(in) :: aa
+   optional                     :: aa
+   character(len=len(aa)+1)     :: jack ! { dg-error "cannot be OPTIONAL" }
+   jack = ''
+end function jack
Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c	(revision 163791)
+++ gcc/fortran/expr.c	(working copy)
@@ -2305,6 +2305,12 @@ check_inquiry (gfc_expr *e, int not_rest
 	      && ap->expr->expr_type != EXPR_VARIABLE
 	      && check_restricted (ap->expr) == FAILURE)
 	  return MATCH_ERROR;
+
+	if (not_restricted == 0
+	    && ap->expr->expr_type == EXPR_VARIABLE
+	    && ap->expr->symtree->n.sym->attr.optional 
+	    && ap->expr->symtree->n.sym->attr.dummy)
+	  return MATCH_NO;
     }
 
   return MATCH_YES;