diff --git a/datastore/query.nim b/datastore/query.nim
index 7cae897..fe6b18f 100644
--- a/datastore/query.nim
+++ b/datastore/query.nim
@@ -22,7 +22,7 @@ type
 
   GetNext* = proc(): Future[?!QueryResponse] {.upraises: [], gcsafe.}
   IterDispose* = proc(): Future[?!void] {.upraises: [], gcsafe.}
-  QueryIter* = ref object
+  QueryIter* {.acyclic.} = ref object
     finished*: bool
     next*: GetNext
     dispose*: IterDispose
diff --git a/datastore/types.nim b/datastore/types.nim
index 473db52..6000faf 100644
--- a/datastore/types.nim
+++ b/datastore/types.nim
@@ -8,4 +8,4 @@ type
   DatastoreKeyNotFound* = object of DatastoreError
   QueryEndedError* = object of DatastoreError
 
-  Datastore* = ref object of RootObj
+  Datastore* {.acyclic.} = ref object of RootObj