Allow lexically declared "arguments" in function scope in sloppy mode.

src/parsing/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/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 4001 matching lines @@
       expected_property_count = function_state.expected_property_count();
       if (use_temp_zone) {
         // If the preconditions are correct the function body should never be
         // accessed, but do this anyway for better behaviour if they're wrong.
         body = nullptr;
       }
     }
 
     // Parsing the body may change the language mode in our scope.
     language_mode = scope->language_mode();
+    scope->DeclareArguments(ast_value_factory());
+    if (main_scope != scope) {
+      main_scope->DeclareArguments(ast_value_factory());
+    }
 
     // Validate name and parameter names. We can do this only after parsing the
     // function, since the function can declare itself strict.
     CheckFunctionName(language_mode, function_name, function_name_validity,
                       function_name_location, CHECK_OK);
     const bool allow_duplicate_parameters =
         is_sloppy(language_mode) && formals.is_simple && !IsConciseMethod(kind);
     ValidateFormalParameters(&formals_classifier, language_mode,
                              allow_duplicate_parameters, CHECK_OK);
 
@@ skipping 2626 matching lines @@
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8