diff --git a/src/api/callback.cc b/src/api/callback.cc
index 885134799fe019..4bcccb960c5556 100644
--- a/src/api/callback.cc
+++ b/src/api/callback.cc
@@ -139,6 +139,11 @@ MaybeLocal<Value> InternalMakeCallback(Environment* env,
                                        Local<Value> argv[],
                                        async_context asyncContext) {
   CHECK(!recv.IsEmpty());
+#ifdef DEBUG
+  for (int i = 0; i < argc; i++)
+    CHECK(!argv[i].IsEmpty());
+#endif
+
   InternalCallbackScope scope(env, recv, asyncContext);
   if (scope.Failed()) {
     return MaybeLocal<Value>();
diff --git a/src/node_errors.cc b/src/node_errors.cc
index 42e19f690514ff..39673abf7f0e41 100644
--- a/src/node_errors.cc
+++ b/src/node_errors.cc
@@ -710,6 +710,7 @@ void DecorateErrorStack(Environment* env,
 void FatalException(Isolate* isolate,
                     Local<Value> error,
                     Local<Message> message) {
+  CHECK(!error.IsEmpty());
   HandleScope scope(isolate);
 
   Environment* env = Environment::GetCurrent(isolate);