Re: [PATCH(es)] PR fortran/77391 -- RFC vote on which you prefer

[Steve Kargl <sgk at troutmask dot apl dot washington dot edu>]

On Fri, Aug 26, 2016 at 10:28:25PM +0200, Mikael Morin wrote:
> Hello,
> 
> Le 26/08/2016 à 20:27, Steve Kargl a écrit :
> > Here are two possible patches for PR fortran/77391.  The first
> > patch treats the invalid code as a GNU Fortran extension as
> > gfortran current accepts the invalid code.  The second patch
> > enforces the standard.  As I think gfortran should encourage
> > standard conformance, I am inclined to commit the second patch.
> > I will however commit the most popular of the two patches tomorrow.
> > Voting starts now and will remain open for 24 hours (give or take
> > a few hours depend on when I awaken).
> >
> 
> I don't think it's sufficient to check current_attr because of this case:
> 
>        character(:) :: a
>        pointer :: a
>        end
> 
> The statement should be accepted, and the check be postponed at a time 
> after the symbol has been initialised, at resolution time for example.
> 

So, I've come up the following.  We now need to debate whether
Dominiq's observations mean that C402 does not apply to named
constant.

2016-08-26  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/77391
	* resolve.c (deferred_requirements): New function to check F2008:C402.
	(resolve_fl_variable,resolve_fl_parameter): Use it.
 
2016-08-26  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/77391
	* gfortran.dg/pr77391.f90: New test.


Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 239762)
+++ gcc/fortran/resolve.c	(working copy)
@@ -11402,6 +11402,27 @@ resolve_fl_variable_derived (gfc_symbol 
 }
 
 
+/* F2008, C402 (R401):  A colon shall not be used as a type-param-value
+   except in the declaration of an entity or component that has the POINTER
+   or ALLOCATABLE attribute.  */
+
+static bool
+deferred_requirements (gfc_symbol *sym)
+{
+  if (sym->ts.deferred
+      && !(sym->attr.pointer
+	   || sym->attr.allocatable
+	   || sym->attr.omp_udr_artificial_var))
+    {
+      gfc_error ("Entity %qs at %L has a deferred type parameter and "
+		 "requires either the POINTER or ALLOCATABLE attribute",
+		 sym->name, &sym->declared_at);
+      return false;
+    }
+  return true;
+}
+
+
 /* Resolve symbols with flavor variable.  */
 
 static bool
@@ -11441,17 +11462,8 @@ resolve_fl_variable (gfc_symbol *sym, in
     }
 
   /* Constraints on deferred type parameter.  */
-  if (sym->ts.deferred
-      && !(sym->attr.pointer
-	   || sym->attr.allocatable
-	   || sym->attr.omp_udr_artificial_var))
-    {
-      gfc_error ("Entity %qs at %L has a deferred type parameter and "
-		 "requires either the pointer or allocatable attribute",
-		     sym->name, &sym->declared_at);
-      specification_expr = saved_specification_expr;
-      return false;
-    }
+  if (!deferred_requirements (sym))
+    return false;
 
   if (sym->ts.type == BT_CHARACTER)
     {
@@ -13570,6 +13582,10 @@ resolve_fl_parameter (gfc_symbol *sym)
       return false;
     }
 
+  /* Constraints on deferred type parameter.  */
+  if (!deferred_requirements (sym))
+    return false;
+
   /* Make sure a parameter that has been implicitly typed still
      matches the implicit type, since PARAMETER statements can precede
      IMPLICIT statements.  */
Index: gcc/testsuite/gfortran.dg/pr77391.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr77391.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/pr77391.f90	(working copy)
@@ -0,0 +1,7 @@
+! { dg-do compile }
+program picky
+character(len=:), parameter :: a="whoops" ! { dg-error "POINTER or ALLOCATABLE" }
+character(len=:) :: b="whoops" ! { dg-error "POINTER or ALLOCATABLE" }
+character(len=:) :: good
+pointer good
+end program picky


-- 
Steve