diff --git a/src/google/protobuf/dynamic_message.cc b/src/google/protobuf/dynamic_message.cc
index 7927107815..c4448d51a0 100644
--- a/src/google/protobuf/dynamic_message.cc
+++ b/src/google/protobuf/dynamic_message.cc
@@ -620,6 +620,7 @@ DynamicMessageFactory::~DynamicMessageFactory() {
 }
 
 const Message* DynamicMessageFactory::GetPrototype(const Descriptor* type) {
+  ABSL_CHECK(type != nullptr);
   absl::MutexLock lock(&prototypes_mutex_);
   return GetPrototypeNoLock(type);
 }
diff --git a/src/google/protobuf/dynamic_message.h b/src/google/protobuf/dynamic_message.h
index 8d53e28cbc..0af9d441b5 100644
--- a/src/google/protobuf/dynamic_message.h
+++ b/src/google/protobuf/dynamic_message.h
@@ -108,8 +108,8 @@ class PROTOBUF_EXPORT DynamicMessageFactory : public MessageFactory {
   // prototype, so these must be destroyed before the DynamicMessageFactory
   // is destroyed.
   //
-  // The given descriptor must outlive the returned message, and hence must
-  // outlive the DynamicMessageFactory.
+  // The given descriptor must be non-null and outlive the returned message, and
+  // hence must outlive the DynamicMessageFactory.
   //
   // The method is thread-safe.
   const Message* GetPrototype(const Descriptor* type) override;