Fix debugger regression in issue 28980

runtime/vm/debugger.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/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "platform/address_sanitizer.h"
 
@@ skipping 677 matching lines @@
     TokenPosition activation_token_pos = TokenPos();
     ASSERT(activation_token_pos.IsReal());
     GetVarDescriptors();
     intptr_t var_desc_len = var_descriptors_.Length();
     for (intptr_t cur_idx = 0; cur_idx < var_desc_len; cur_idx++) {
       RawLocalVarDescriptors::VarInfo var_info;
       var_descriptors_.GetInfo(cur_idx, &var_info);
       const int8_t kind = var_info.kind();
       if ((kind == RawLocalVarDescriptors::kContextLevel) &&
           (var_info.begin_pos <= activation_token_pos) &&
-          (activation_token_pos <= var_info.end_pos)) {
+          (activation_token_pos < var_info.end_pos)) {
         // This var_descriptors_ entry is a context scope which is in scope
         // of the current token position. Now check whether it is shadowing
         // the previous context scope.
         if (innermost_begin_pos < var_info.begin_pos) {
           innermost_begin_pos = var_info.begin_pos;
           context_level_ = var_info.index();
         }
       }
     }
     ASSERT(context_level_ >= 0);
@@ skipping 3402 matching lines @@
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart