There are only 2 language modes, not 3

src/objects-inl.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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5997 matching lines @@
 }
 
 void SharedFunctionInfo::set_optimization_disabled(bool disable) {
   set_compiler_hints(BooleanBit::set(compiler_hints(),
                                      kOptimizationDisabled,
                                      disable));
 }
 
 
 LanguageMode SharedFunctionInfo::language_mode() {
-  STATIC_ASSERT(LANGUAGE_END == 3);
+  STATIC_ASSERT(LANGUAGE_END == 2);
   return construct_language_mode(
       BooleanBit::get(compiler_hints(), kStrictModeFunction));
 }
 
 
 void SharedFunctionInfo::set_language_mode(LanguageMode language_mode) {
-  STATIC_ASSERT(LANGUAGE_END == 3);
+  STATIC_ASSERT(LANGUAGE_END == 2);
   // We only allow language mode transitions that set the same language mode
   // again or go up in the chain:
   DCHECK(is_sloppy(this->language_mode()) || is_strict(language_mode));
   int hints = compiler_hints();
   hints = BooleanBit::set(hints, kStrictModeFunction, is_strict(language_mode));
   set_compiler_hints(hints);
 }
 
 
 FunctionKind SharedFunctionInfo::kind() {
@@ skipping 2183 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_