Revert changes 17962-3 which break Dartium Debug build.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index b038b990eaf1d2abcce50d0378022ebb4bfaac02..ec3cb206e35b43b1992e18f0eb9d9c9d888b73f6 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -1443,9 +1443,7 @@ RawType* Class::SignatureType() const {
   ASSERT(!signature_types.IsNull());
   if (signature_types.Length() > 0) {
     // At most one signature type per signature class.
-    ASSERT((signature_types.Length() == 1) ||
-           ((signature_types.Length() == 2) &&
-            (signature_types.At(1) == Type::null())));
+    ASSERT(signature_types.Length() == 1);
     Type& signature_type = Type::Handle();
     signature_type ^= signature_types.At(0);
     ASSERT(!signature_type.IsNull());
@@ -1917,29 +1915,7 @@ RawClass* Class::New(const String& name,
 
 RawClass* Class::NewSignatureClass(const String& name,
                                    const Function& signature_function,
-                                   const Script& script,
-                                   intptr_t token_pos) {
-  const Class& result = Class::Handle(New<Instance>(name, script, token_pos));
-  const Type& super_type = Type::Handle(Type::ObjectType());
-  ASSERT(!super_type.IsNull());
-  // Instances of a signature class can only be closures.
-  result.set_instance_size(Closure::InstanceSize());
-  result.set_next_field_offset(Closure::InstanceSize());
-  result.set_super_type(super_type);
-  result.set_type_arguments_field_offset(Closure::type_arguments_offset());
-  // Implements interface "Function".
-  const Type& function_type = Type::Handle(Type::Function());
-  const Array& interfaces = Array::Handle(Array::New(1, Heap::kOld));
-  interfaces.SetAt(0, function_type);
-  result.set_interfaces(interfaces);
-  if (!signature_function.IsNull()) {
-    result.PatchSignatureFunction(signature_function);
-  }
-  return result.raw();
-}
-
-
-void Class::PatchSignatureFunction(const Function& signature_function) const {
+                                   const Script& script) {
   ASSERT(!signature_function.IsNull());
   const Class& owner_class = Class::Handle(signature_function.Owner());
   ASSERT(!owner_class.IsNull());
@@ -1947,25 +1923,51 @@ void Class::PatchSignatureFunction(const Function& signature_function) const {
   // A signature class extends class Instance and is parameterized in the same
   // way as the owner class of its non-static signature function.
   // It is not type parameterized if its signature function is static.
-  // In case of a function type alias, the function owner is the alias class
-  // instead of the enclosing class.
   if (!signature_function.is_static() &&
       (owner_class.NumTypeParameters() > 0) &&
       !signature_function.HasInstantiatedSignature()) {
     type_parameters = owner_class.type_parameters();
   }
-  set_signature_function(signature_function);
-  set_type_parameters(type_parameters);
-  if (owner_class.raw() == raw()) {
-    // This signature class is an alias, which cannot be the canonical
-    // signature class for this signature function.
-    ASSERT(!IsCanonicalSignatureClass());
-  } else if (signature_function.signature_class() == Object::null()) {
-    // Make this signature class the canonical signature class.
-    signature_function.set_signature_class(*this);
-    ASSERT(IsCanonicalSignatureClass());
+  const intptr_t token_pos = signature_function.token_pos();
+  Class& result = Class::Handle(New<Instance>(name, script, token_pos));
+  const Type& super_type = Type::Handle(Type::ObjectType());
+  ASSERT(!super_type.IsNull());
+  result.set_instance_size(Closure::InstanceSize());
+  result.set_next_field_offset(Closure::InstanceSize());
+  result.set_super_type(super_type);
+  result.set_signature_function(signature_function);
+  result.set_type_parameters(type_parameters);
+  result.SetFields(Object::empty_array());
+  result.SetFunctions(Object::empty_array());
+  result.set_type_arguments_field_offset(
+      Closure::type_arguments_offset());
+  // Implements interface "Function".
+  const Type& function_type = Type::Handle(Type::Function());
+  const Array& interfaces = Array::Handle(Array::New(1, Heap::kOld));
+  interfaces.SetAt(0, function_type);
+  result.set_interfaces(interfaces);
+  // Unless the signature function already has a signature class, create a
+  // canonical signature class by having the signature function point back to
+  // the signature class.
+  if (signature_function.signature_class() == Object::null()) {
+    signature_function.set_signature_class(result);
+    result.set_is_finalized();
+  } else {
+    // This new signature class is an alias.
+    ASSERT(!result.IsCanonicalSignatureClass());
+    // Do not yet mark it as finalized, so that the class finalizer can check it
+    // for illegal self references.
+    result.set_is_prefinalized();
   }
-  set_is_prefinalized();
+  // Instances of a signature class can only be closures.
+  ASSERT(result.instance_size() == Closure::InstanceSize());
+  // Cache the signature type as the first canonicalized type in result.
+  const Type& signature_type = Type::Handle(result.SignatureType());
+  ASSERT(!signature_type.IsFinalized());
+  const Array& new_canonical_types = Array::Handle(Array::New(1, Heap::kOld));
+  new_canonical_types.SetAt(0, signature_type);
+  result.set_canonical_types(new_canonical_types);
+  return result.raw();
 }
 
 
@@ -4211,8 +4213,7 @@ RawFunction* Function::ImplicitClosureFunction() const {
     const Script& script = Script::Handle(this->script());
     signature_class = Class::NewSignatureClass(signature,
                                                closure_function,
-                                               script,
-                                               closure_function.token_pos());
+                                               script);
     library.AddClass(signature_class);
   } else {
     closure_function.set_signature_class(signature_class);
@@ -4237,9 +4238,8 @@ RawString* Function::BuildSignature(
       GrowableObjectArray::Handle(GrowableObjectArray::New());
   String& name = String::Handle();
   if (!instantiate && !is_static() && (name_visibility == kInternalName)) {
-    // Prefix the signature with its signature class and type parameters, if any
-    // (e.g. "Map<K, V>(K) => bool"). In case of a function type alias, the
-    // signature class name is the alias name.
+    // Prefix the signature with its class and type parameters, if any (e.g.
+    // "Map<K, V>(K) => bool").
     // The signature of static functions cannot be type parameterized.
     const Class& function_class = Class::Handle(Owner());
     ASSERT(!function_class.IsNull());