Reland of [parsing] Fix maybe-assigned for loop variables.

test/cctest/scope-test-helper.h

 // Copyright 2017 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.
 
 #ifndef V8_CCTEST_SCOPE_TEST_HELPER_H_
 #define V8_CCTEST_SCOPE_TEST_HELPER_H_
 
 #include "src/ast/scopes.h"
 #include "src/ast/variables.h"
 
@@ skipping 14 matching lines @@
     for (Scope* inner = scope->inner_scope(); inner != nullptr;
          inner = inner->sibling()) {
       if (!ScopeTreeIsHidden(inner)) {
         return false;
       }
     }
     return true;
   }
 
   static void CompareScopeToData(Scope* scope, const PreParsedScopeData* data,
-                                 size_t& index) {
+                                 size_t& index, bool precise_maybe_assigned) {
     CHECK_EQ(data->backing_store_[index++], scope->scope_type());
     CHECK_EQ(data->backing_store_[index++], scope->start_position());
     CHECK_EQ(data->backing_store_[index++], scope->end_position());
 
     int inner_scope_count = 0;
     for (Scope* inner = scope->inner_scope(); inner != nullptr;
          inner = inner->sibling()) {
       // FIXME(marja): This is probably not the right condition for knowing what
       // scopes are present in the preparse data.
       if (!ScopeTreeIsHidden(inner)) {
@@ skipping 17 matching lines @@
           local->mode() == CONST) {
 #ifdef DEBUG
         const AstRawString* local_name = local->raw_name();
         int name_length = data->backing_store_[index++];
         CHECK_EQ(name_length, local_name->length());
         for (int i = 0; i < name_length; ++i) {
           CHECK_EQ(data->backing_store_[index++], local_name->raw_data()[i]);
         }
 #endif
         CHECK_EQ(data->backing_store_[index++], local->location());
-        CHECK_EQ(data->backing_store_[index++], local->maybe_assigned());
+        if (precise_maybe_assigned) {
+          CHECK_EQ(data->backing_store_[index++], local->maybe_assigned());
+        } else {
+          STATIC_ASSERT(kMaybeAssigned > kNotAssigned);
+          CHECK_GE(data->backing_store_[index++], local->maybe_assigned());
+        }
       }
     }
 
     for (Scope* inner = scope->inner_scope(); inner != nullptr;
          inner = inner->sibling()) {
       if (!ScopeTreeIsHidden(inner)) {
-        CompareScopeToData(inner, data, index);
+        CompareScopeToData(inner, data, index, precise_maybe_assigned);
       }
     }
   }
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_SCOPE_TEST_HELPER_H_