re PR c++/43281 ([c++0x] ICE with invalid auto)

	PR c++/43281
	* pt.c (contains_auto_r): New fn.
	(do_auto_deduction): Use it.
	(tsubst): Don't look at TREE_TYPE of a TEMPLATE_TYPE_PARM.

From-SVN: r157651

gcc/cp/ChangeLog

+2010-03-22  Jason Merrill  <jason@redhat.com>
+
+	PR c++/43281
+	* pt.c (contains_auto_r): New fn.
+	(do_auto_deduction): Use it.
+	(tsubst): Don't look at TREE_TYPE of a TEMPLATE_TYPE_PARM.
+
 2010-03-20  Simon Martin  <simartin@users.sourceforge.net>
 
 	PR c++/43081:

gcc/cp/pt.c

@@ -9921,6 +9921,7 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 
   if (type
       && TREE_CODE (t) != TYPENAME_TYPE
+      && TREE_CODE (t) != TEMPLATE_TYPE_PARM
       && TREE_CODE (t) != IDENTIFIER_NODE
       && TREE_CODE (t) != FUNCTION_TYPE
       && TREE_CODE (t) != METHOD_TYPE)
@@ -18240,6 +18241,20 @@ listify_autos (tree type, tree auto_node)
   return tsubst (type, argvec, tf_warning_or_error, NULL_TREE);
 }
 
+/* walk_tree helper for do_auto_deduction.  */
+
+static tree
+contains_auto_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
+		 void *type)
+{
+  /* Is this a variable with the type we're looking for?  */
+  if (DECL_P (*tp)
+      && TREE_TYPE (*tp) == type)
+    return *tp;
+  else
+    return NULL_TREE;
+}
+
 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
    from INIT.  AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.  */
 
@@ -18248,8 +18263,19 @@ do_auto_deduction (tree type, tree init, tree auto_node)
 {
   tree parms, tparms, targs;
   tree args[1];
+  tree decl;
   int val;
 
+  /* The name of the object being declared shall not appear in the
+     initializer expression.  */
+  decl = cp_walk_tree_without_duplicates (&init, contains_auto_r, type);
+  if (decl)
+    {
+      error ("variable %q#D with %<auto%> type used in its own "
+	     "initializer", decl);
+      return error_mark_node;
+    }
+
   /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
      with either a new invented type template parameter U or, if the
      initializer is a braced-init-list (8.5.4), with

gcc/testsuite/ChangeLog

 2010-03-22  Jason Merrill  <jason@redhat.com>
 
+	PR c++/43281
+	* g++.dg/cpp0x/auto18.C: New.
+
 	* gcc.dg/pr36997.c: Adjust error message.
 	* g++.dg/ext/vector9.C: Likewise.
 	* g++.dg/conversion/simd3.C: Likewise.

gcc/testsuite/g++.dg/cpp0x/auto18.C

+// { dg-options "-std=c++0x" }
+
+void f()
+{
+  auto val = val;  // { dg-error "auto. type used in its own initializer" }
+}