c++: Identifier type value should not update binding

This simplification removes some unneeded behaviour in
set_identifier_type_value_with_scope, which was updating the namespace
binding.  And causing update_binding to have to deal with meeting two
implicit typedefs.  But the typedef is already there, and there's no
other way to have two such typedef's collide (we'll already have dealt
with that in lookup_elaborated_type).

So, let's kill this crufty code.

	gcc/cp/
	* name-lookup.c (update_binding): We never meet two implicit
	typedefs.
	(do_pushdecl): Adjust set_identifier_type_value_with_scope calls.
	(set_identifier_type_value_with_scope): Do not update binding in
	the namespace-case.  Assert it is already there.

1 files changed, 22 insertions, 28 deletions

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 184e9c8..f195e81 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -2365,33 +2365,24 @@ update_binding (cp_binding_level *level, cxx_binding *binding, tree *slot,
   if (old == error_mark_node)
     old = NULL_TREE;
 
-  if (TREE_CODE (decl) == TYPE_DECL && DECL_ARTIFICIAL (decl))
+  if (DECL_IMPLICIT_TYPEDEF_P (decl))
     {
-      tree other = to_type;
-
-      if (old && TREE_CODE (old) == TYPE_DECL && DECL_ARTIFICIAL (old))
-	other = old;
-
-      /* Pushing an artificial typedef.  See if this matches either
-	 the type slot or the old value slot.  */
-      if (!other)
-	;
-      else if (same_type_p (TREE_TYPE (other), TREE_TYPE (decl)))
-	/* Two artificial decls to same type.  Do nothing.  */
-	return other;
-      else
-	goto conflict;
+      /* Pushing an artificial decl.  We should not find another
+         artificial decl here already -- lookup_elaborated_type will
+         have already found it.  */
+      gcc_checking_assert (!to_type
+			   && !(old && DECL_IMPLICIT_TYPEDEF_P (old)));
 
       if (old)
 	{
 	  /* Slide decl into the type slot, keep old unaltered  */
 	  to_type = decl;
 	  to_val = old;
-	  goto done;
 	}
+      goto done;
     }
 
-  if (old && TREE_CODE (old) == TYPE_DECL && DECL_ARTIFICIAL (old))
+  if (old && DECL_IMPLICIT_TYPEDEF_P (old))
     {
       /* Slide old into the type slot.  */
       to_type = old;
@@ -3122,7 +3113,7 @@ do_pushdecl (tree decl, bool hiding)
 
 	  if (TREE_CODE (decl) == NAMESPACE_DECL)
 	    /* A local namespace alias.  */
-	    set_identifier_type_value (name, NULL_TREE);
+	    set_identifier_type_value_with_scope (name, NULL_TREE, level);
 
 	  if (!binding)
 	    binding = create_local_binding (level, name);
@@ -3150,10 +3141,7 @@ do_pushdecl (tree decl, bool hiding)
 	      if (TYPE_NAME (type) != decl)
 		set_underlying_type (decl);
 
-	      if (!ns)
-		set_identifier_type_value_with_scope (name, decl, level);
-	      else
-		SET_IDENTIFIER_TYPE_VALUE (name, global_type_node);
+	      set_identifier_type_value_with_scope (name, decl, level);
 	    }
 
 	  /* If this is a locally defined typedef in a function that
@@ -3768,8 +3756,9 @@ identifier_type_value (tree id)
 }
 
 /* Push a definition of struct, union or enum tag named ID.  into
-   binding_level B.  DECL is a TYPE_DECL for the type.  We assume that
-   the tag ID is not already defined.  */
+   binding_level B.  DECL is a TYPE_DECL for the type.  DECL has
+   already been pushed into its binding level.  This is bookkeeping to
+   find it easily.  */
 
 static void
 set_identifier_type_value_with_scope (tree id, tree decl, cp_binding_level *b)
@@ -3781,20 +3770,25 @@ set_identifier_type_value_with_scope (tree id, tree decl, cp_binding_level *b)
       /* Shadow the marker, not the real thing, so that the marker
 	 gets restored later.  */
       tree old_type_value = REAL_IDENTIFIER_TYPE_VALUE (id);
-      b->type_shadowed
-	= tree_cons (id, old_type_value, b->type_shadowed);
+      b->type_shadowed = tree_cons (id, old_type_value, b->type_shadowed);
       type = decl ? TREE_TYPE (decl) : NULL_TREE;
       TREE_TYPE (b->type_shadowed) = type;
     }
   else
     {
-      tree *slot = find_namespace_slot (current_namespace, id, true);
       gcc_assert (decl);
-      update_binding (b, NULL, slot, MAYBE_STAT_DECL (*slot), decl);
+      if (CHECKING_P)
+	{
+	  tree *slot = find_namespace_slot (current_namespace, id);
+	  gcc_checking_assert (slot
+			       && (decl == MAYBE_STAT_TYPE (*slot)
+				   || decl == MAYBE_STAT_DECL (*slot)));
+	}
 
       /* Store marker instead of real type.  */
       type = global_type_node;
     }
+
   SET_IDENTIFIER_TYPE_VALUE (id, type);
 }