[parsing] Be less pessimistic about maybe_assigned of parameters.

src/ast/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/scopes.h"
 
 #include <set>
 
 #include "src/accessors.h"
 #include "src/ast/ast.h"
@@ skipping 1918 matching lines @@
   // The same parameter may occur multiple times in the parameters_ list.
   // If it does, and if it is not copied into the context object, it must
   // receive the highest parameter index for that parameter; thus iteration
   // order is relevant!
   for (int i = num_parameters() - 1; i >= 0; --i) {
     Variable* var = params_[i];
     DCHECK(!has_rest_ || var != rest_parameter());
     DCHECK_EQ(this, var->scope());
     if (uses_sloppy_arguments) {
       var->set_is_used();
+      var->set_maybe_assigned();
       var->ForceContextAllocation();
     }
     AllocateParameter(var, i);
   }
 }
 
 void DeclarationScope::AllocateParameter(Variable* var, int index) {
   if (MustAllocate(var)) {
     if (MustAllocateInContext(var)) {
       DCHECK(var->IsUnallocated() || var->IsContextSlot());
@@ skipping 163 matching lines @@
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8