When converting Maybe and MaybeLocal values with a check, always check

include/v8.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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 421 matching lines @@
   }
 
   V8_INLINE bool IsEmpty() const { return val_ == nullptr; }
 
   template <class S>
   V8_WARN_UNUSED_RESULT V8_INLINE bool ToLocal(Local<S>* out) const {
     out->val_ = IsEmpty() ? nullptr : this->val_;
     return !IsEmpty();
   }
 
-  // Will crash when checks are enabled if the MaybeLocal<> is empty.
+  // Will crash if the MaybeLocal<> is empty.
   V8_INLINE Local<T> ToLocalChecked();
 
   template <class S>
   V8_INLINE Local<S> FromMaybe(Local<S> default_value) const {
     return IsEmpty() ? default_value : Local<S>(val_);
   }
 
  private:
   T* val_;
 };
@@ skipping 5614 matching lines @@
                        int internal_field_index1,
                        // Must be 1 or -1.
                        int internal_field_index2,
                        WeakCallbackInfo<void>::Callback weak_callback);
   static void* ClearWeak(internal::Object** global_handle);
   static void Eternalize(Isolate* isolate,
                          Value* handle,
                          int* index);
   static Local<Value> GetEternal(Isolate* isolate, int index);
 
-  static void CheckIsJust(bool is_just);
+  static void FromJustIsNothing();
   static void ToLocalEmpty();
   static void InternalFieldOutOfBounds(int index);
 
   template <class T> friend class Handle;
   template <class T> friend class Local;
   template <class T>
   friend class MaybeLocal;
   template <class T>
   friend class Maybe;
   template <class T>
@@ skipping 14 matching lines @@
  * e.g. because a previous API call threw an exception that hasn't been caught
  * yet, or because a TerminateExecution exception was thrown. In that case, a
  * "Nothing" value is returned.
  */
 template <class T>
 class Maybe {
  public:
   V8_INLINE bool IsNothing() const { return !has_value; }
   V8_INLINE bool IsJust() const { return has_value; }
 
-  // Will crash when checks are enabled if the Maybe<> is nothing.
+  // Will crash if the Maybe<> is nothing.
   V8_INLINE T FromJust() const {
-#ifdef V8_ENABLE_CHECKS
-    V8::CheckIsJust(IsJust());
-#endif
+    if (V8_UNLIKELY(!IsJust())) V8::FromJustIsNothing();
     return value;
   }
 
   V8_INLINE T FromMaybe(const T& default_value) const {
     return has_value ? value : default_value;
   }
 
   V8_INLINE bool operator==(const Maybe& other) const {
     return (IsJust() == other.IsJust()) &&
            (!IsJust() || FromJust() == other.FromJust());
@@ skipping 797 matching lines @@
 
 
 template<class T>
 Local<T> Eternal<T>::Get(Isolate* isolate) {
   return Local<T>(reinterpret_cast<T*>(*V8::GetEternal(isolate, index_)));
 }
 
 
 template <class T>
 Local<T> MaybeLocal<T>::ToLocalChecked() {
-#ifdef V8_ENABLE_CHECKS
-  if (val_ == nullptr) V8::ToLocalEmpty();
-#endif
+  if (V8_UNLIKELY(val_ == nullptr)) V8::ToLocalEmpty();
   return Local<T>(val_);
 }
 
 
 template <class T>
 void* WeakCallbackInfo<T>::GetInternalField(int index) const {
 #ifdef V8_ENABLE_CHECKS
   if (index < 0 || index >= kInternalFieldsInWeakCallback) {
     V8::InternalFieldOutOfBounds(index);
   }
@@ skipping 1145 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_