re PR c++/68726 (ice: tree check: expected tree_vec, have error_mark in…

re PR c++/68726 (ice: tree check: expected tree_vec, have error_mark in comp_template_args_with_info, at cp/pt.c:7890)

/cp
2016-02-11  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/68726
	* pt.c (lookup_template_class_1): Check tsubst return value for
	error_mark_node.

/testsuite
2016-02-11  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/68726
	* g++.dg/cpp0x/pr68726.C: New.

From-SVN: r233340

gcc/cp/pt.c

@@ -8547,6 +8547,8 @@ lookup_template_class_1 (tree d1, tree arglist, tree in_decl, tree context,
 		    arglist, complain, NULL_TREE);
 	  --processing_template_decl;
 	  TREE_VEC_LENGTH (arglist)++;
+	  if (partial_inst_args == error_mark_node)
+	    return error_mark_node;
 	  use_partial_inst_tmpl =
 	    /*...and we must not be looking at the partial instantiation
 	     itself. */