Improve error message for duplicate parameters

src/parser.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/ast-literal-reindexer.h"
 #include "src/bailout-reason.h"
@@ skipping 2039 matching lines @@
       //
       // because the var declaration is hoisted to the function scope where 'x'
       // is already bound.
       DCHECK(IsDeclaredVariableMode(var->mode()));
       if (is_strict(language_mode()) || allow_harmony_sloppy()) {
         // In harmony we treat re-declarations as early errors. See
         // ES5 16 for a definition of early errors.
         if (declaration_kind == DeclarationDescriptor::NORMAL) {
           ParserTraits::ReportMessage(MessageTemplate::kVarRedeclaration, name);
         } else {
-          ParserTraits::ReportMessage(MessageTemplate::kStrictParamDupe);
+          ParserTraits::ReportMessage(MessageTemplate::kParamDupe);
         }
         *ok = false;
         return nullptr;
       }
       Expression* expression = NewThrowSyntaxError(
           MessageTemplate::kVarRedeclaration, name, declaration->position());
       declaration_scope->SetIllegalRedeclaration(expression);
     } else if (mode == VAR) {
       var->set_maybe_assigned();
     }
@@ skipping 3878 matching lines @@
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(
       ast_value_factory()->reflect_construct_string(), NULL, args, pos);
 }
 }  // namespace internal
 }  // namespace v8