[parser] Enforce module-specific identifier restriction

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index ecea789cc0f6f0aaf081dac108c7eb69672bee4d..3fd3ce84807547a6ca8799c7ade400d0c74a616c 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -55,6 +55,12 @@ class PreParserIdentifier {
   static PreParserIdentifier Constructor() {
     return PreParserIdentifier(kConstructorIdentifier);
   }
+  static PreParserIdentifier Enum() {
+    return PreParserIdentifier(kEnumIdentifier);
+  }
+  static PreParserIdentifier Await() {
+    return PreParserIdentifier(kAwaitIdentifier);
+  }
   bool IsEval() const { return type_ == kEvalIdentifier; }
   bool IsArguments() const { return type_ == kArgumentsIdentifier; }
   bool IsEvalOrArguments() const { return IsEval() || IsArguments(); }
@@ -64,7 +70,8 @@ class PreParserIdentifier {
   bool IsYield() const { return type_ == kYieldIdentifier; }
   bool IsPrototype() const { return type_ == kPrototypeIdentifier; }
   bool IsConstructor() const { return type_ == kConstructorIdentifier; }
-  bool IsFutureReserved() const { return type_ == kFutureReservedIdentifier; }
+  bool IsEnum() const { return type_ == kEnumIdentifier; }
+  bool IsAwait() const { return type_ == kAwaitIdentifier; }
   bool IsFutureStrictReserved() const {
     return type_ == kFutureStrictReservedIdentifier ||
            type_ == kLetIdentifier || type_ == kStaticIdentifier ||
@@ -91,7 +98,9 @@ class PreParserIdentifier {
     kArgumentsIdentifier,
     kUndefinedIdentifier,
     kPrototypeIdentifier,
-    kConstructorIdentifier
+    kConstructorIdentifier,
+    kEnumIdentifier,
+    kAwaitIdentifier
   };
 
   explicit PreParserIdentifier(Type type) : type_(type) {}
@@ -974,12 +983,21 @@ class PreParser : public ParserBase<PreParserTraits> {
   // during parsing.
   PreParseResult PreParseProgram(int* materialized_literals = 0,
                                  bool is_module = false) {
-    Scope* scope = NewScope(scope_, is_module ? MODULE_SCOPE : SCRIPT_SCOPE);
+    Scope* scope = NewScope(scope_, SCRIPT_SCOPE);
+
+    // ModuleDeclarationInstantiation for Source Text Module Records creates a
+    // new Module Environment Record whose outer lexical environment record is
+    // the global scope.
+    if (is_module) {
+      scope = NewScope(scope, MODULE_SCOPE);
+    }
+
     PreParserFactory factory(NULL);
     FunctionState top_scope(&function_state_, &scope_, scope, kNormalFunction,
                             &factory);
     bool ok = true;
     int start_position = scanner()->peek_location().beg_pos;
+    parsing_module_ = is_module;
     ParseStatementList(Token::EOS, &ok);
     if (stack_overflow()) return kPreParseStackOverflow;
     if (!ok) {
@@ -1002,9 +1020,12 @@ class PreParser : public ParserBase<PreParserTraits> {
   // keyword and parameters, and have consumed the initial '{'.
   // At return, unless an error occurred, the scanner is positioned before the
   // the final '}'.
-  PreParseResult PreParseLazyFunction(
-      LanguageMode language_mode, FunctionKind kind, bool has_simple_parameters,
-      ParserRecorder* log, Scanner::BookmarkScope* bookmark, int* use_counts);
+  PreParseResult PreParseLazyFunction(LanguageMode language_mode,
+                                      FunctionKind kind,
+                                      bool has_simple_parameters,
+                                      bool parsing_module, ParserRecorder* log,
+                                      Scanner::BookmarkScope* bookmark,
+                                      int* use_counts);
 
  private:
   friend class PreParserTraits;