diff --git a/libquassel-protocol/src/main/kotlin/de/justjanne/libquassel/protocol/syncables/StatefulSyncableObject.kt b/libquassel-protocol/src/main/kotlin/de/justjanne/libquassel/protocol/syncables/StatefulSyncableObject.kt
index e3260e3ce920e2bbc24a458c4027d7fc3f713d9d..6f7e60e9a7a98a847cc094a4662e4a405469351f 100644
--- a/libquassel-protocol/src/main/kotlin/de/justjanne/libquassel/protocol/syncables/StatefulSyncableObject.kt
+++ b/libquassel-protocol/src/main/kotlin/de/justjanne/libquassel/protocol/syncables/StatefulSyncableObject.kt
@@ -39,7 +39,7 @@ abstract class StatefulSyncableObject<T>(
     return result
   }
 
-  override fun state(): T = state.value
-  override fun flow(): Flow<T> = state
+  final override fun state(): T = state.value
+  final override fun flow(): Flow<T> = state
   protected val state = MutableStateFlow(state)
 }
diff --git a/libquassel-protocol/src/test/kotlin/de/justjanne/libquassel/protocol/testutil/mocks/EmptySession.kt b/libquassel-protocol/src/test/kotlin/de/justjanne/libquassel/protocol/testutil/mocks/EmptySession.kt
index 703e1d8a4babeb77ac23506187abbdfb0ef483a8..f57502359fb66013117686798999a072f5b65e8a 100644
--- a/libquassel-protocol/src/test/kotlin/de/justjanne/libquassel/protocol/testutil/mocks/EmptySession.kt
+++ b/libquassel-protocol/src/test/kotlin/de/justjanne/libquassel/protocol/testutil/mocks/EmptySession.kt
@@ -55,7 +55,7 @@ open class EmptySession : Session {
   override fun removeIdentity(id: IdentityId) = Unit
   override fun identities() = emptySet<Identity>()
 
-  override fun certManager(id: IdentityId) = null
+  override fun certManager(id: IdentityId): CertManager? = null
   override fun certManagers() = emptySet<CertManager>()
 
   override fun rename(className: String, oldName: String, newName: String) = Unit