Make sure the bound of a mixin type parameter is finalized before instantiating

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 45585)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -1683,6 +1683,13 @@
           param ^= mixin_type_args.TypeAt(i);
           param_bound = param.bound();
           if (!param_bound.IsInstantiated()) {
+            // Make sure the bound is finalized before instantiating it.
+            if (!param_bound.IsFinalized() &&
+                !param_bound.IsBeingFinalized()) {
+              param_bound =
+                  FinalizeType(mixin_app_class, param_bound, kCanonicalize);
+              param.set_bound(param_bound);

[Ivan Posva, 2015/05/07 13:21:25]

Can you please add a comment why this is necessary here? It will be overridden
again on line 1699 further down.

[regis, 2015/05/07 13:33:53]

In case the bound is part of a recursive type, it may be reached again (via the
mixin app class type parameters) during the instantiation step.
Added comment.

+            }
             param_bound = param_bound.InstantiateFrom(mixin_type_args,
                                                       &bound_error);
             // The instantiator contains only TypeParameter objects and no