Preparse functions in the scope that was created when parsing of the function was started

src/parsing/preparser.cc

Index: src/parsing/preparser.cc
diff --git a/src/parsing/preparser.cc b/src/parsing/preparser.cc
index 37beecf5a40aedfc577c3b2432a7085081e26f58..062e18a01deb74c6538f913f3ffef08903f03836 100644
--- a/src/parsing/preparser.cc
+++ b/src/parsing/preparser.cc
@@ -70,26 +70,22 @@ PreParserIdentifier PreParser::GetSymbol() const {
 }
 
 PreParser::PreParseResult PreParser::PreParseLazyFunction(
-    LanguageMode language_mode, FunctionKind kind, bool has_simple_parameters,
-    bool parsing_module, ParserRecorder* log, bool may_abort, int* use_counts) {
+    DeclarationScope* function_scope, bool parsing_module, ParserRecorder* log,
+    bool may_abort, int* use_counts) {
+  DCHECK_EQ(FUNCTION_SCOPE, function_scope->scope_type());
   parsing_module_ = parsing_module;
   log_ = log;
   use_counts_ = use_counts;
   // Lazy functions always have trivial outer scopes (no with/catch scopes).
   DCHECK_NULL(scope_state_);
-  DeclarationScope* top_scope = NewScriptScope();
-  FunctionState top_state(&function_state_, &scope_state_, top_scope,
-                          kNormalFunction);
-  scope()->SetLanguageMode(language_mode);
-  DeclarationScope* function_scope = NewFunctionScope(kind);
-  if (!has_simple_parameters) function_scope->SetHasNonSimpleParameters();
   FunctionState function_state(&function_state_, &scope_state_, function_scope,
-                               kind);
+                               function_scope->function_kind());
   DCHECK_EQ(Token::LBRACE, scanner()->current_token());
   bool ok = true;
   int start_position = peek_position();
   LazyParsingResult result = ParseLazyFunctionLiteralBody(may_abort, &ok);
   use_counts_ = nullptr;
+  function_scope->ResetAfterPreparsing();
   if (result == kLazyParsingAborted) {
     return kPreParseAbort;
   } else if (stack_overflow()) {
@@ -98,7 +94,7 @@ PreParser::PreParseResult PreParser::PreParseLazyFunction(
     ReportUnexpectedToken(scanner()->current_token());
   } else {
     DCHECK_EQ(Token::RBRACE, scanner()->peek());
-    if (is_strict(scope()->language_mode())) {
+    if (is_strict(function_scope->language_mode())) {

[marja, 2016/09/26 12:38:27]

Here we have already reset the function scope, and then we read data from it...
hmmmm.... in this case you don't clear language_mode, but it's quite a
surprising pattern.

       int end_pos = scanner()->location().end_pos;
       CheckStrictOctalLiteral(start_position, end_pos, &ok);
       CheckDecimalLiteralWithLeadingZero(start_position, end_pos);