Patch classes do not need to be finalized

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 42584)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -2306,6 +2306,14 @@
   if (cls.is_finalized()) {
     return;
   }
+  if (cls.is_patch()) {
+    // The fields and functions of a patch class are copied to the
+    // patched class after parsing. There is nothing to finalize.

[Ivan Posva, 2015/01/03 01:14:19]

We should also make sure that we do not waste a class id on the patch class.

[hausner, 2015/01/05 20:56:29]

As per our off-line conversation, I'm leaving this as is. Assigning a class id
is done at the lowest level when allocating a new class object. Changing this
would be outside of this CL.

+    ASSERT(Array::Handle(cls.functions()).Length() == 0);
+    ASSERT(Array::Handle(cls.fields()).Length() == 0);
+    cls.set_is_finalized();
+    return;
+  }
   if (FLAG_trace_class_finalization) {
     OS::Print("Finalize %s\n", cls.ToCString());
   }