diff --git a/src/Filter.c b/src/Filter.c
index b1e91bb..1ef4fed 100644
--- a/src/Filter.c
+++ b/src/Filter.c
@@ -28,5 +28,7 @@
 HashMap *
 FilterApply(Filter * filter, HashMap * event)
 {
+    (void) filter;
+    (void) event;
     return NULL;
 }
diff --git a/src/Room.c b/src/Room.c
index c13441d..791c5d3 100644
--- a/src/Room.c
+++ b/src/Room.c
@@ -42,6 +42,8 @@ struct Room
 Room *
 RoomCreate(Db * db, RoomCreateRequest * req)
 {
+    (void) db;
+    (void) req;
     return NULL;
 }
 
diff --git a/src/Routes/RouteRoomAliases.c b/src/Routes/RouteRoomAliases.c
index ad288e6..44eadfe 100644
--- a/src/Routes/RouteRoomAliases.c
+++ b/src/Routes/RouteRoomAliases.c
@@ -37,6 +37,10 @@ ROUTE_IMPL(RouteRoomAliases, path, argp)
     Db *db = args->matrixArgs->db;
     DbRef *ref = NULL;
 
+    (void) roomId;
+
+    /* TODO: Placeholder; remove. */
+    goto finish;
 finish:
     DbUnlock(db, ref);
     JsonFree(request);
diff --git a/src/State.c b/src/State.c
index 7d2fe3a..66c69c0 100644
--- a/src/State.c
+++ b/src/State.c
@@ -33,12 +33,14 @@
 static HashMap *
 StateResolveV1(Array * states)
 {
+    (void) states;
     return NULL;
 }
 
 static HashMap *
 StateResolveV2(Array * states)
 {
+    (void) states;
     return NULL;
 }