typeck.c (get_delta_difference): Give hard error for conversion from virtual base.

	* typeck.c (get_delta_difference): Give hard error for conversion
	from virtual base.
	* cp-tree.h: Tweak formatting.

From-SVN: r18229

gcc/cp/ChangeLog

+Wed Feb 25 09:51:29 1998  Jason Merrill  <jason@yorick.cygnus.com>
+
+	* typeck.c (get_delta_difference): Give hard error for conversion
+	from virtual base.
+
+	* cp-tree.h: Tweak formatting.
+
 Wed Feb 25 00:35:33 1998  Jason Merrill  <jason@yorick.cygnus.com>
 
 	* decl.c (push_namespace): Handle redeclaration error.

gcc/cp/cp-tree.h

@@ -29,7 +29,7 @@ Boston, MA 02111-1307, USA.  */
 struct lang_identifier
 {
   struct tree_identifier ignore;
-  tree global_value, local_value;
+  tree namespace_bindings, local_value;
   tree class_value;
   tree class_template_info;
   struct lang_id2 *x;
@@ -58,8 +58,8 @@ typedef struct
   tree decl;
 } template_parm_index;
 
-#define BINDING_SCOPE(NODE)    (((struct tree_binding*)NODE)->scope)
-#define BINDING_VALUE(NODE)   (((struct tree_binding*)NODE)->value)
+#define BINDING_SCOPE(NODE)	(((struct tree_binding*)NODE)->scope)
+#define BINDING_VALUE(NODE)	(((struct tree_binding*)NODE)->value)
 #define NAMESPACE_BINDING(ID,NS) BINDING_VALUE (binding_for_name (ID, NS))
 #define IDENTIFIER_GLOBAL_VALUE(NODE) \
   NAMESPACE_BINDING (NODE, global_namespace)
@@ -80,7 +80,7 @@ struct tree_binding
 /* Macros for access to language-specific slots in an identifier.  */
 
 #define IDENTIFIER_NAMESPACE_BINDINGS(NODE)	\
-  (((struct lang_identifier *)(NODE))->global_value)
+  (((struct lang_identifier *)(NODE))->namespace_bindings)
 #define IDENTIFIER_CLASS_VALUE(NODE)	\
   (((struct lang_identifier *)(NODE))->class_value)
 #define IDENTIFIER_LOCAL_VALUE(NODE)	\

gcc/cp/typeck.c

@@ -6304,24 +6304,8 @@ get_delta_difference (from, to, force)
 	  return delta;
 	}
       binfo = get_binfo (to, from, 1);
-      if (binfo == error_mark_node)
-	{
-	  if (!force)
-	    error ("   in pointer to member conversion");
-	  return delta;
-	}
-      if (binfo == 0)
-	{
-	  if (!force)
-	    cp_error ("cannot convert pointer to member of type %T to unrelated pointer to member of type %T", from, to);
-	  return delta;
-	}
-      if (TREE_VIA_VIRTUAL (binfo))
-	{
-	  binfo = binfo_member (BINFO_TYPE (binfo),
-				CLASSTYPE_VBASECLASSES (from));
-	  warning ("pointer to member conversion to virtual base class will only work if you are very careful");
-	}
+      if (binfo == 0 || binfo == error_mark_node || TREE_VIA_VIRTUAL (binfo))
+	return delta;
       delta = BINFO_OFFSET (binfo);
       delta = cp_convert (ptrdiff_type_node, delta);
       
@@ -6329,10 +6313,21 @@ get_delta_difference (from, to, force)
 			      integer_zero_node,
 			      delta, 1);
     }
+
   if (TREE_VIA_VIRTUAL (binfo))
     {
-      warning ("pointer to member conversion from virtual base class will only work if you are very careful");
+      if (force)
+	{
+	  cp_warning ("pointer to member cast from virtual base `%T'",
+		      BINFO_TYPE (binfo));
+	  warning ("  will only work if you are very careful");
+	}
+      else
+	cp_error ("pointer to member conversion from virtual base `%T'",
+		  BINFO_TYPE (binfo));
+      return delta;
     }
+
   return BINFO_OFFSET (binfo);
 }