Compile implicit closures as dispatchers instead of duplicating the original method's code.

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 6252 matching lines @@
     context_scope = LocalScope::CreateImplicitClosureScope(*this);
   }
   closure_function.set_context_scope(context_scope);
 
   // Set closure function's result type to this result type.
   closure_function.set_result_type(AbstractType::Handle(result_type()));
 
   // Set closure function's end token to this end token.
   closure_function.set_end_token_pos(end_token_pos());
 
+  // The closurized method stub just calls into the original method and should
+  // therefore be skipped by the debugger and in stack traces.
+  closure_function.set_is_debuggable(false);
+  closure_function.set_is_visible(false);
+
   // Set closure function's formal parameters to this formal parameters,
   // removing the receiver if this is an instance method and adding the closure
   // object as first parameter.
   const int kClosure = 1;
   const int has_receiver = is_static() ? 0 : 1;
   const int num_fixed_params = kClosure - has_receiver + num_fixed_parameters();
   const int num_opt_params = NumOptionalParameters();
   const bool has_opt_pos_params = HasOptionalPositionalParameters();
   const int num_params = num_fixed_params + num_opt_params;
   closure_function.set_num_fixed_parameters(num_fixed_params);
@@ skipping 14442 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart