PreParser: track variable declarations and parameters

src/parsing/preparser.cc

 // Copyright 2011 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 <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 278 matching lines @@
   if (declaration->pattern.identifiers_ != nullptr) {
     DCHECK(FLAG_lazy_inner_functions);
     /* Mimic what Parser does when declaring variables (see
        Parser::PatternRewriter::VisitVariableProxy).
 
        var + no initializer -> RemoveUnresolved
        let / const + no initializer -> RemoveUnresolved
        var + initializer -> RemoveUnresolved followed by NewUnresolved
        let / const + initializer -> RemoveUnresolved
     */
-
+    Scope* scope = declaration_descriptor->hoist_scope;
+    if (scope == nullptr) {
+      scope = this->scope();
+    }
     if (declaration->initializer.IsEmpty() ||
         (declaration_descriptor->mode == VariableMode::LET ||
          declaration_descriptor->mode == VariableMode::CONST)) {
       for (auto identifier : *(declaration->pattern.identifiers_)) {
         declaration_descriptor->scope->RemoveUnresolved(identifier);
       }
     }
+    for (auto identifier : *(declaration->pattern.identifiers_)) {
+      scope->DeclareVariableName(identifier, declaration_descriptor->mode);
+    }
   }
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_CUSTOM
 
 
 }  // namespace internal
 }  // namespace v8