Clean up finalization of recursive types in the VM.

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/become.h"
@@ skipping 16939 matching lines @@
     TrailPtr instantiation_trail,
     TrailPtr bound_trail,
     Heap::Space space) const {
   Zone* zone = Thread::Current()->zone();
   ASSERT(IsFinalized() || IsBeingFinalized());
   ASSERT(!IsInstantiated());
   // Return the uninstantiated type unchanged if malformed. No copy needed.
   if (IsMalformed()) {
     return raw();
   }
-  // Instantiating this type with its own type arguments as instantiator can
-  // occur during finalization and bounds checking. Return the type unchanged.
-  if (arguments() == instantiator_type_arguments.raw()) {
-    return raw();
-  }
   // Note that the type class has to be resolved at this time, but not
   // necessarily finalized yet. We may be checking bounds at compile time or
   // finalizing the type argument vector of a recursive type.
   const Class& cls = Class::Handle(zone, type_class());
   TypeArguments& type_arguments = TypeArguments::Handle(zone, arguments());
   ASSERT(type_arguments.Length() == cls.NumTypeArguments());
   type_arguments =
       type_arguments.InstantiateFrom(instantiator_type_arguments, bound_error,
                                      instantiation_trail, bound_trail, space);
   // This uninstantiated type is not modified, as it can be instantiated
   // with different instantiators. Allocate a new instantiated version of it.
   const Type& instantiated_type =
       Type::Handle(zone, Type::New(cls, type_arguments, token_pos(), space));
   // Preserve the bound error if any.
   if (IsMalbounded()) {
     const LanguageError& bound_error = LanguageError::Handle(zone, error());
     instantiated_type.set_error(bound_error);
   }
   // Preserve the signature if this type represents a function type.
   // Note that the types in the signature remain unchanged. They get indirectly
   // instantiated by instantiating the type arguments above.
   const Function& sig_fun = Function::Handle(zone, signature());
   if (!sig_fun.IsNull()) {
     instantiated_type.set_signature(sig_fun);
   }
   if (IsFinalized()) {
     instantiated_type.SetIsFinalized();
   } else {
     instantiated_type.SetIsResolved();
+    if (IsBeingFinalized()) {
+      instantiated_type.SetIsBeingFinalized();
+    }
   }
   // Canonicalization is not part of instantiation.
   return instantiated_type.raw();
 }
 
 
 bool Type::IsEquivalent(const Instance& other, TrailPtr trail) const {
   ASSERT(!IsNull());
   if (raw() == other.raw()) {
     return true;
@@ skipping 6129 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart