diff --git a/src/protocol/mod.rs b/src/protocol/mod.rs
index f8fa2a8c7997917373315e46cdab473febf83d45..af9724fc4040d2aae15a500acdfcc49b4f73c19b 100644
--- a/src/protocol/mod.rs
+++ b/src/protocol/mod.rs
@@ -51,6 +51,7 @@ pub enum ComponentCreationError {
     DefinitionNotComponent,
     InvalidNumArguments,
     InvalidArgumentType(usize),
+    UnownedPort,
 }
 
 impl std::fmt::Debug for ProtocolDescription {