diff --git a/Interface.cpp b/Interface.cpp
index 8370c36..44eb872 100644
--- a/Interface.cpp
+++ b/Interface.cpp
@@ -68,6 +68,9 @@
     LAST_HIDL_TRANSACTION   = 0x0fffffff,
 };
 
+const std::unique_ptr<ConstantExpression> Interface::FLAG_ONE_WAY =
+    std::make_unique<LiteralConstantExpression>(ScalarType::KIND_UINT32, 0x01, "oneway");
+
 Interface::Interface(const char* localName, const FQName& fullName, const Location& location,
                      Scope* parent, const Reference<Type>& superType, const Hash* fileHash)
     : Scope(localName, fullName, location, parent), mSuperType(superType), mFileHash(fileHash) {}