Do not look for the slot in the ScopeInfo's global range when it's not necessary.

src/debug/debug-evaluate.cc

Index: src/debug/debug-evaluate.cc
diff --git a/src/debug/debug-evaluate.cc b/src/debug/debug-evaluate.cc
index 8d7635c01df8088e8afa34fd1dffb419d3e6ff67..b24956132424705258f3517d28b7aa7dd5de346d 100644
--- a/src/debug/debug-evaluate.cc
+++ b/src/debug/debug-evaluate.cc
@@ -280,15 +280,14 @@ Handle<Context> DebugEvaluate::ContextBuilder::MaterializeReceiver(
   switch (scope_info->scope_type()) {
     case FUNCTION_SCOPE: {
       VariableMode mode;
-      VariableLocation location;
       InitializationFlag init_flag;
       MaybeAssignedFlag maybe_assigned_flag;
 
       // Don't bother creating a fake context node if "this" is in the context
       // already.
-      if (ScopeInfo::ContextSlotIndex(
-              scope_info, isolate_->factory()->this_string(), &mode, &location,
-              &init_flag, &maybe_assigned_flag) >= 0) {
+      if (ScopeInfo::ContextSlotIndex(scope_info,
+                                      isolate_->factory()->this_string(), &mode,
+                                      &init_flag, &maybe_assigned_flag) >= 0) {
         return target;
       }
       receiver = handle(frame_->receiver(), isolate_);