Make stray 'return' an early error

src/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 904 matching lines @@
   }
 
   PreParserExpression NewThrowReferenceError(const char* type, int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewThrowSyntaxError(
       const char* type, Handle<Object> arg, int pos) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewThrowTypeError(
-      const char* type, Handle<Object> arg1, Handle<Object> arg2, int pos) {
+      const char* type, Handle<Object> arg, int pos) {
     return PreParserExpression::Default();
   }
 
   // Reporting errors.
   void ReportMessageAt(Scanner::Location location,
                        const char* message,
                        Vector<const char*> args,
                        bool is_reference_error = false);
   void ReportMessageAt(Scanner::Location location,
                        const char* type,
@@ skipping 1241 matching lines @@
                                "accessor_get_set");
     }
     *ok = false;
   }
 }
 
 
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H