Implement new optional parameters syntax in the vm (issue 4290).

runtime/vm/dart_api_impl.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 "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 2821 matching lines @@
   const Function& func = Api::UnwrapFunctionHandle(isolate, function);
   if (func.IsNull()) {
     RETURN_TYPE_ERROR(isolate, function, Function);
   }
 
   // We hide implicit parameters, such as a method's receiver. This is
   // consistent with Invoke or New, which don't expect their callers to
   // provide them in the argument lists they are handed.
   *fixed_param_count = (func.num_fixed_parameters() -
                         func.NumberOfImplicitParameters());
-  *opt_param_count = func.num_optional_parameters();
+  // TODO(regis): Separately report named and positional optional param counts.
+  *opt_param_count = (func.num_optional_positional_parameters() +
+                      func.num_optional_named_parameters());
 
   ASSERT(*fixed_param_count >= 0);
   ASSERT(*opt_param_count >= 0);
 
   return Api::Success(isolate);
 }
 
 
 DART_EXPORT Dart_Handle Dart_GetVariableNames(Dart_Handle target) {
   Isolate* isolate = Isolate::Current();
@@ skipping 1326 matching lines @@
 DART_EXPORT void Dart_InitPerfEventsSupport(Dart_FileWriterFunction function) {
   Dart::set_perf_events_writer(function);
 }
 
 
 DART_EXPORT void Dart_InitFlowGraphPrinting(Dart_FileWriterFunction function) {
   Dart::set_flow_graph_writer(function);
 }
 
 }  // namespace dart