[Bug c++/70205] [4.9/5/6 Regression] ICE on valid code on x86_64-linux-gnu: tree check: expected tree_binfo, have error_mark in add_candidates, at cp/call.c:5283

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70205

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This patch makes us compile the testcase and also passes dg.exp testsuite.  But
my understanding of BASELINK stuff is too weak to gauge whether this is
reasonable approach.

--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -8125,6 +8125,10 @@ build_new_method_call_1 (tree instance, tree fns,
vec<tree, va_gc> **args,
   /* Dismantle the baselink to collect all the information we need.  */
   if (!conversion_path)
     conversion_path = BASELINK_BINFO (fns);
+
+  if (conversion_path == error_mark_node)
+    return error_mark_node;
+
   access_binfo = BASELINK_ACCESS_BINFO (fns);
   binfo = BASELINK_BINFO (fns);
   optype = BASELINK_OPTYPE (fns);