re PR c++/81229 (ICE in c_tree_chain_next on aarch64)

	PR c++/81229
	* name-lookup.c (do_pushdecl): Reset IDENTIFIER_TYPE when finding
	a matching TYPE_DECL.

	* g++.dg/lookup/pr81229.C: New.

From-SVN: r249835

gcc/cp/ChangeLog

+2017-06-30  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/81229
+	* name-lookup.c (do_pushdecl): Reset IDENTIFIER_TYPE when finding
+	a matching TYPE_DECL.
+
 2017-06-29  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* class.c (add_method): Change pair of errors to error + inform.

gcc/cp/name-lookup.c

@@ -2354,9 +2354,13 @@ do_pushdecl (tree decl, bool is_friend)
 	  ; /* Ignore using decls here.  */
 	else if (tree match = duplicate_decls (decl, *iter, is_friend))
 	  {
-	    if (iter.hidden_p ()
-		&& match != error_mark_node
-		&& !DECL_HIDDEN_P (match))
+	    if (match == error_mark_node)
+	      ;
+	    else if (TREE_CODE (match) == TYPE_DECL)
+	      /* The IDENTIFIER will have the type referring to the
+		 now-smashed TYPE_DECL, because ...?  Reset it.  */
+	      SET_IDENTIFIER_TYPE_VALUE (name, TREE_TYPE (match));
+	    else if (iter.hidden_p () && !DECL_HIDDEN_P (match))
 	      {
 		/* Unhiding a previously hidden decl.  */
 		tree head = iter.reveal_node (old);

gcc/testsuite/ChangeLog

+2017-06-30  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/81229
+	* g++.dg/lookup/pr81229.C: New.
+
 2017-06-30  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/81021

gcc/testsuite/g++.dg/lookup/pr81229.C

+// PR c++/81229 GC ICE with stale pointed in identifier type.
+// { dg-additional-options "--param ggc-min-heapsize=0" }
+
+typedef unsigned L;
+typedef unsigned L;
+
+L l;