Remove redundant/unnecessary variables and checks in ParseForStatement

src/parsing/preparser.cc

 // Copyright 2011 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 <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 906 matching lines @@
     if (peek() == Token::VAR || (peek() == Token::CONST && allow_const()) ||
         (peek() == Token::LET && IsNextLetKeyword())) {
       int decl_count;
       bool is_lexical;
       bool is_binding_pattern;
       Scanner::Location first_initializer_loc = Scanner::Location::invalid();
       Scanner::Location bindings_loc = Scanner::Location::invalid();
       ParseVariableDeclarations(kForStatement, &decl_count, &is_lexical,
                                 &is_binding_pattern, &first_initializer_loc,
                                 &bindings_loc, CHECK_OK);
-      bool accept_IN = decl_count >= 1;
-      if (accept_IN && CheckInOrOf(&mode, ok)) {
+      if (CheckInOrOf(&mode, ok)) {
         if (!*ok) return Statement::Default();
         if (decl_count != 1) {
-          const char* loop_type =
-              mode == ForEachStatement::ITERATE ? "for-of" : "for-in";
           PreParserTraits::ReportMessageAt(
               bindings_loc, MessageTemplate::kForInOfLoopMultiBindings,
-              loop_type);
+              ForEachStatement::VisitModeString(mode));
           *ok = false;
           return Statement::Default();
         }
         if (first_initializer_loc.IsValid() &&
             (is_strict(language_mode()) || mode == ForEachStatement::ITERATE ||
              is_lexical || is_binding_pattern)) {
-          if (mode == ForEachStatement::ITERATE) {
-            ReportMessageAt(first_initializer_loc,
-                            MessageTemplate::kForOfLoopInitializer);
-          } else {
-            // TODO(caitp): This should be an error in sloppy mode, too.
-            ReportMessageAt(first_initializer_loc,
-                            MessageTemplate::kForInLoopInitializer);
-          }
+          PreParserTraits::ReportMessageAt(
+              first_initializer_loc, MessageTemplate::kForInOfLoopInitializer,
+              ForEachStatement::VisitModeString(mode));
           *ok = false;
           return Statement::Default();
         }
 
         if (mode == ForEachStatement::ITERATE) {
           ExpressionClassifier classifier;
           Expression enumerable =
               ParseAssignmentExpression(true, &classifier, CHECK_OK);
           PreParserTraits::RewriteNonPattern(enumerable, &classifier, CHECK_OK);
         } else {
@@ skipping 341 matching lines @@
     Expect(Token::RBRACE, CHECK_OK);
     return PreParserExpression::Default();
   }
 }
 
 #undef CHECK_OK
 
 
 }  // namespace internal
 }  // namespace v8