[parser] disallow language mode directive in body of function with non-simple parameters

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index b1541f616afe133554881e99aec4f71a9f5e45e0..b1e6ad8309661e590156c7c15df1235c44cb8729 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -102,8 +102,8 @@ PreParserExpression PreParserTraits::ParseFunctionLiteral(
 
 
 PreParser::PreParseResult PreParser::PreParseLazyFunction(
-    LanguageMode language_mode, FunctionKind kind, ParserRecorder* log,
-    Scanner::BookmarkScope* bookmark) {
+    LanguageMode language_mode, FunctionKind kind, bool has_simple_parameters,
+    ParserRecorder* log, Scanner::BookmarkScope* bookmark) {
   log_ = log;
   // Lazy functions always have trivial outer scopes (no with/catch scopes).
   Scope* top_scope = NewScope(scope_, SCRIPT_SCOPE);
@@ -113,6 +113,7 @@ PreParser::PreParseResult PreParser::PreParseLazyFunction(
   scope_->SetLanguageMode(language_mode);
   Scope* function_scope = NewScope(
       scope_, IsArrowFunction(kind) ? ARROW_SCOPE : FUNCTION_SCOPE, kind);
+  if (!has_simple_parameters) function_scope->SetHasNonSimpleParameters();
   PreParserFactory function_factory(NULL);
   FunctionState function_state(&function_state_, &scope_, function_scope, kind,
                                &function_factory);
@@ -251,15 +252,35 @@ void PreParser::ParseStatementList(int end_token, bool* ok,
     }
 
     if (directive_prologue) {
-      if (statement.IsUseStrictLiteral()) {
+      bool use_strict_found = statement.IsUseStrictLiteral();
+      bool use_strong_found =
+          statement.IsUseStrongLiteral() && allow_strong_mode();
+
+      if (use_strict_found) {
         scope_->SetLanguageMode(
             static_cast<LanguageMode>(scope_->language_mode() | STRICT));
-      } else if (statement.IsUseStrongLiteral() && allow_strong_mode()) {
+      } else if (use_strong_found) {
         scope_->SetLanguageMode(static_cast<LanguageMode>(
             scope_->language_mode() | STRONG));
       } else if (!statement.IsStringLiteral()) {
         directive_prologue = false;
       }
+
+      if (use_strict_found || use_strong_found) {
+        if (!scope_->HasSimpleParameters()) {

[rossberg, 2015/08/24 13:11:08]

Nit: merge conditions

[conradw, 2015/08/25 11:31:20]

Done.

+          // A block declaration scope as a child scope of a function scope

[rossberg, 2015/08/24 13:11:08]

Not sure how the comment relates to the code. Which block scope?

[conradw, 2015/08/25 11:31:20]

I think this is referring to HasSimpleParameters looking up the flag in the
ClosureScope. I've reworded it anyway.

+          // indicates that a function has a non-simple parameter list.
+          // TC39 deemed "use strict" directives to be an error in this case,
+          // on 29/7/2015. https://goo.gl/ueA7Ln
+          //
+          // In V8, this also applies to "use strong " directives.
+          PreParserTraits::ReportMessageAt(
+              token_loc, MessageTemplate::kIllegalLanguageModeDirective,
+              use_strict_found ? "use strict" : "use strong");
+          *ok = false;
+          return;
+        }
+      }
     }
 
     // If we're allowed to reset to a bookmark, we will do so when we see a long
@@ -1057,7 +1078,7 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   Expect(Token::LPAREN, CHECK_OK);
   int start_position = scanner()->location().beg_pos;
   function_scope->set_start_position(start_position);
-  PreParserFormalParameters formals(nullptr);
+  PreParserFormalParameters formals(function_scope);
   ParseFormalParameterList(&formals, &formals_classifier, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
   int formals_end_position = scanner()->location().end_pos;