Strawman: check strong mode free variables against the global object.

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index c744dd418bbaaca2b74567048f30ecf208274da3..7e7955fba17c3dc0e13703b5ed5a0c2ce2ac0f24 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -593,8 +593,9 @@ class VarAndOrder {
 };
 
 
-void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals,
-                                         ZoneList<Variable*>* context_locals) {
+void Scope::CollectStackAndContextLocals(
+    ZoneList<Variable*>* stack_locals, ZoneList<Variable*>* context_locals,
+    ZoneList<Variable*>* strong_mode_free_variables) {
   DCHECK(stack_locals != NULL);
   DCHECK(context_locals != NULL);
 
@@ -628,6 +629,11 @@ void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals,
        p != NULL;
        p = variables_.Next(p)) {
     Variable* var = reinterpret_cast<Variable*>(p->value);
+    if (is_strong(language_mode()) && strong_mode_free_variables &&
+        var->mode() == DYNAMIC_GLOBAL) {
+      strong_mode_free_variables->Add(var, zone());
+    }
+
     if (var->is_used()) {
       vars.Add(VarAndOrder(var, p->order), zone());
     }