Follow-up to capturing instantiator

runtime/vm/scopes.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/scopes.h"
 
 #include "vm/ast.h"
 #include "vm/bit_vector.h"
 #include "vm/object.h"
 #include "vm/parser.h"
@@ skipping 324 matching lines @@
         }
       }
       return var;
     }
     current_scope = current_scope->parent();
   }
   return NULL;
 }
 
 
-void LocalScope::CaptureVariable(const String& name) {
+bool LocalScope::CaptureVariable(const String& name) {
   ASSERT(name.IsSymbol());
   LocalScope* current_scope = this;
   while (current_scope != NULL) {
     LocalVariable* var = current_scope->LocalLookupVariable(name);
     if (var != NULL) {
       if (var->owner()->function_level() != function_level()) {
         var->set_is_captured();
       }
       // Insert aliases of the variable in intermediate scopes.
       LocalScope* intermediate_scope = this;
       while (intermediate_scope != current_scope) {
         intermediate_scope->variables_.Add(var);
         ASSERT(var->owner() != intermediate_scope);  // Item is an alias.
         intermediate_scope = intermediate_scope->parent();
       }
-      return;
+      return true;
     }
     current_scope = current_scope->parent();
   }
+  return false;
 }
 
 
 SourceLabel* LocalScope::LookupLabel(const String& name) {
   LocalScope* current_scope = this;
   while (current_scope != NULL) {
     SourceLabel* label = current_scope->LocalLookupLabel(name);
     if (label != NULL) {
       return label;
     }
@@ skipping 224 matching lines @@
     return fixed_parameter_count - (index() - kParamEndSlotFromFp);
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count - (index() - kFirstLocalSlotFromFp);
   }
 }
 
 
 }  // namespace dart