Fix issue 18435.

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/object.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
@@ skipping 33 matching lines @@
   while (current_scope != NULL) {
     if (current_scope == scope) {
       return true;
     }
     current_scope = current_scope->parent();
   }
   return false;
 }
 
 
+void LocalScope::Clear() {
+  variables_.Clear();
+}
+
+
 bool LocalScope::AddVariable(LocalVariable* variable) {
   ASSERT(variable != NULL);
   if (LocalLookupVariable(variable->name()) != NULL) {
     return false;
   }
   variables_.Add(variable);
   if (variable->owner() == NULL) {
     // Variables must be added to their owner scope first. Subsequent calls
     // to 'add' treat the variable as an alias.
     variable->set_owner(this);
@@ skipping 567 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