re PR fortran/50404 (SIGSEGV in gfc_resolve_close)

	PR fortran/50404
	* io.c (gfc_resolve_close): CLOSE requires a UNIT.
	* gfortran.dg/io_constraints_3.f90: Improve testcase.

From-SVN: r181183

gcc/fortran/ChangeLog

 2011-11-08  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
+	PR fortran/50404
+	* io.c (gfc_resolve_close): CLOSE requires a UNIT.
+
+2011-11-08  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
+
 	PR fortran/50409
 	* expr.c (gfc_simplify_expr): Substrings can't have negative
 	length.

gcc/fortran/io.c

@@ -2295,6 +2295,24 @@ gfc_resolve_close (gfc_close *close)
   if (gfc_reference_st_label (close->err, ST_LABEL_TARGET) == FAILURE)
     return FAILURE;
 
+  if (close->unit == NULL)
+    {
+      /* Find a locus from one of the arguments to close, when UNIT is
+	 not specified.  */
+      locus loc = gfc_current_locus;
+      if (close->status)
+	loc = close->status->where;
+      else if (close->iostat)
+	loc = close->iostat->where;
+      else if (close->iomsg)
+	loc = close->iomsg->where;
+      else if (close->err)
+	loc = close->err->where;
+
+      gfc_error ("CLOSE statement at %L requires a UNIT number", &loc);
+      return FAILURE;
+    }
+
   if (close->unit->expr_type == EXPR_CONSTANT
       && close->unit->ts.type == BT_INTEGER
       && mpz_sgn (close->unit->value.integer) < 0)

gcc/testsuite/ChangeLog

 2011-11-08  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
+	PR fortran/50404
+	* gfortran.dg/io_constraints_3.f90: Improve testcase.
+
+2011-11-08  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
+
 	PR fortran/50409
-	* gcc/testsuite/gfortran.dg/string_5.f90: Improve testcase.
+	* gfortran.dg/string_5.f90: Improve testcase.
 
 2011-10-23  Jason Merrill  <jason@redhat.com>
 

gcc/testsuite/gfortran.dg/io_constraints_3.f90

@@ -66,6 +66,7 @@
   close(10, iostat=u,status="keep")
   close(10, iostat=u,status="delete")
   close(10, iostat=u,status=foo) ! { dg-warning "STATUS specifier in CLOSE statement" }
+  close(iostat=u) ! { dg-error "requires a UNIT number" }