[parser] use-strict directives in function body affect init block

src/parser.h

 // Copyright 2012 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_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // TODO(titzer): remove this include dependency
@@ skipping 1137 matching lines @@
   // If bookmark is set, the (pre-)parser may decide to abort skipping
   // in order to force the function to be eagerly parsed, after all.
   // In this case, it'll reset the scanner using the bookmark.
   void SkipLazyFunctionBody(int* materialized_literal_count,
                             int* expected_property_count, bool* ok,
                             Scanner::BookmarkScope* bookmark = nullptr);
 
   PreParser::PreParseResult ParseLazyFunctionBodyWithPreParser(
       SingletonLogger* logger, Scanner::BookmarkScope* bookmark = nullptr);
 
+  bool IsSimpleParameterList(
+      const ParserFormalParameterParsingState& formal_parameters);
   Block* BuildParameterInitializationBlock(
       const ParserFormalParameterParsingState& formal_parameters, bool* ok);
 
   // Consumes the ending }.
   ZoneList<Statement*>* ParseEagerFunctionBody(
       const AstRawString* function_name, int pos,
       const ParserFormalParameterParsingState& formal_parameters,
       Variable* fvar, Token::Value fvar_init_op, FunctionKind kind, bool* ok);
 
   void ThrowPendingError(Isolate* isolate, Handle<Script> script);
@@ skipping 163 matching lines @@
   if (is_duplicate) {
     classifier->RecordDuplicateFormalParameterError(
         parser_->scanner()->location());
   }
 }
 
 
 void ParserTraits::AddParameterInitializationBlock(
     const ParserFormalParameterParsingState& formal_parameters,
     ZoneList<v8::internal::Statement*>* body, bool* ok) {
+  if (parser_->IsSimpleParameterList(formal_parameters)) return;
   auto* init_block =
       parser_->BuildParameterInitializationBlock(formal_parameters, ok);
   if (!*ok) return;
   if (init_block != nullptr) {
     body->Add(init_block, parser_->zone());
   }
 }
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_