[C++ Patch] PR 68726 ("ice: tree check: expected tree_vec, have error_mark in comp_template_args_with_info, at cp/pt.c:7890")

[Paolo Carlini]

Hi,

turns out, this small ICE on invalid is actually a regression, I can 
only reproduce it in trunk. Anyway, the ICE occurs immediately when, 
during error recovery, comp_template_args gets an error_mark_node as 
second argument. Tested x86_64-linux.

Thanks,
Paolo.

P.S. Second try: the first time my message was rejected as spam!?!

///////////


/cp
2016-02-10  Paolo Carlini  <paolo.carl...@oracle.com>

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

/testsuite
2016-02-10  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/68726
        * g++.dg/cpp0x/pr68726.C: New.
Index: cp/pt.c
===================================================================
--- cp/pt.c     (revision 233308)
+++ cp/pt.c     (working copy)
@@ -8547,6 +8547,8 @@ lookup_template_class_1 (tree d1, tree arglist, tr
                    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. */
Index: testsuite/g++.dg/cpp0x/pr68726.C
===================================================================
--- testsuite/g++.dg/cpp0x/pr68726.C    (revision 0)
+++ testsuite/g++.dg/cpp0x/pr68726.C    (working copy)
@@ -0,0 +1,7 @@
+// { dg-do compile { target c++11 } }
+
+template <typename> struct A {
+  template <typename, > struct __construct_helper;  // { dg-error "expected" }
+  template <typename... _Args>
+  using __has_construct typename __construct_helper<_Args...>::type;  // { 
dg-error "expected" }
+} struct : A<int> {  // { dg-error "expected" }