Add debugging info for 'this'

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 177 matching lines @@
       ContextScope::Handle(func.context_scope());
   if (!context_scope.IsNull()) {
     ASSERT(func.IsLocalFunction());
     for (int i = 0; i < context_scope.num_variables(); i++) {
       VarDesc desc;
       desc.name = &String::Handle(context_scope.NameAt(i));
       desc.info.kind =  RawLocalVarDescriptors::kContextVar;
       desc.info.scope_id = context_scope.ContextLevelAt(i);
       desc.info.begin_pos = begin_token_pos();
       desc.info.end_pos = end_token_pos();
+      ASSERT(desc.info.begin_pos <= desc.info.end_pos);
       desc.info.index = context_scope.ContextIndexAt(i);
       vars.Add(desc);
     }
   }
   // Now collect all variables from local scopes.
   int16_t scope_id = 0;
   CollectLocalVariables(&vars, &scope_id);
 
   const LocalVarDescriptors& var_desc =
       LocalVarDescriptors::Handle(LocalVarDescriptors::New(vars.length()));
@@ skipping 367 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