There are only 2 language modes, not 3

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index e83d8b6096358b865ad58503a2eef602d72d8212..3d82bf8205a895693d45fc1d1a27e3118c8959ec 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -6015,14 +6015,14 @@ void SharedFunctionInfo::set_optimization_disabled(bool 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));