Implement generic function type syntax in the VM (fixes #27966).

runtime/vm/class_finalizer.cc

 // Copyright (c) 2013, 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/class_finalizer.h"
 
 #include "vm/code_generator.h"
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
@@ skipping 564 matching lines @@
         // TODO(regis): As long as we support metadata in typedef signatures,
         // we cannot reset these fields used to reparse a typedef.
         // Note that the scope class of a typedef function type is always
         // preserved as the typedef class (not reset to _Closure class), thereby
         // preventing sharing of canonical function types between typedefs.
         // Not being shared, these fields are therefore always meaningful for
         // typedefs.
         if (!scope_class.IsTypedefClass()) {
           signature.set_owner(Object::Handle());
           signature.set_token_pos(TokenPosition::kNoSource);
+          if ((type.arguments() != TypeArguments::null()) &&
+              signature.HasInstantiatedSignature()) {
+            ASSERT(scope_class.IsGeneric());
+            // Although the scope class of this function type is generic,
+            // the signature of this function type does not refer to any
+            // of its type parameters. Reset its scope class to _Closure.
+            Type::Cast(type).set_type_class(Class::Handle(
+                Isolate::Current()->object_store()->closure_class()));
+            type.set_arguments(Object::null_type_arguments());
+          }
         }
       }
     }
   }
 }
 
 
 void ClassFinalizer::FinalizeTypeParameters(const Class& cls,
                                             PendingTypes* pending_types) {
   if (FLAG_trace_type_finalization) {
@@ skipping 104 matching lines @@
     ResolveUpperBounds(type_class);
   }
 
   // The finalized type argument vector needs num_type_arguments types.
   const intptr_t num_type_arguments = type_class.NumTypeArguments();
   // The class has num_type_parameters type parameters.
   const intptr_t num_type_parameters = type_class.NumTypeParameters();
 
   // If we are not reifying types, drop type arguments.
   if (!FLAG_reify) {
-    type.set_arguments(TypeArguments::Handle(zone, TypeArguments::null()));
+    type.set_arguments(Object::null_type_arguments());
   }
 
   // Initialize the type argument vector.
   // Check the number of parsed type arguments, if any.
   // Specifying no type arguments indicates a raw type, which is not an error.
   // However, type parameter bounds are checked below, even for a raw type.
   TypeArguments& arguments = TypeArguments::Handle(zone, type.arguments());
   if (!arguments.IsNull() && (arguments.Length() != num_type_parameters)) {
     // Wrong number of type arguments. The type is mapped to the raw type.
     if (Isolate::Current()->error_on_bad_type()) {
@@ skipping 2678 matching lines @@
   ASSERT(fields_array.Length() == ByteBuffer::NumberOfFields());
   field ^= fields_array.At(0);
   ASSERT(field.Offset() == ByteBuffer::data_offset());
   name ^= field.name();
   expected_name ^= String::New("_data");
   ASSERT(String::EqualsIgnoringPrivateKey(name, expected_name));
 #endif
 }
 
 }  // namespace dart