Leave uninitialized type arguments of a type being finalized as null instead of

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 3795 matching lines @@
   }
   return true;
 }
 
 
 bool TypeArguments::IsInstantiated(GrowableObjectArray* trail) const {
   AbstractType& type = AbstractType::Handle();
   const intptr_t num_types = Length();
   for (intptr_t i = 0; i < num_types; i++) {
     type = TypeAt(i);
-    ASSERT(!type.IsNull());
-    if (!type.IsInstantiated(trail)) {
+    if (!type.IsBeingFinalized() && !type.IsInstantiated(trail)) {
       return false;
     }
   }
   return true;
 }
 
 
 bool TypeArguments::IsUninstantiatedIdentity() const {
   ASSERT(!IsInstantiated());
   AbstractType& type = AbstractType::Handle();
@@ skipping 143 matching lines @@
       IsUninstantiatedIdentity() &&
       (instantiator_type_arguments.Length() == Length())) {
     return instantiator_type_arguments.raw();
   }
   const intptr_t num_types = Length();
   TypeArguments& instantiated_array =
       TypeArguments::Handle(TypeArguments::New(num_types, Heap::kNew));
   AbstractType& type = AbstractType::Handle();
   for (intptr_t i = 0; i < num_types; i++) {
     type = TypeAt(i);
-    if (!type.IsInstantiated()) {
+    if (!type.IsBeingFinalized() && !type.IsInstantiated()) {
       type = type.InstantiateFrom(instantiator_type_arguments,
                                   bound_error,
                                   trail);
     }
     instantiated_array.SetTypeAt(i, type);
   }
   return instantiated_array.raw();
 }
 
 
@@ skipping 12983 matching lines @@
   return "_MirrorReference";
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   Instance::PrintToJSONStream(stream, ref);
 }
 
 
 }  // namespace dart