diff --git a/chronos/asyncfutures2.nim b/chronos/asyncfutures2.nim
index 2b2311bef..614be3db2 100644
--- a/chronos/asyncfutures2.nim
+++ b/chronos/asyncfutures2.nim
@@ -39,7 +39,7 @@ type
     state*: FutureState
     error*: ref CatchableError ## Stored exception
     mustCancel*: bool
-    id*: uint64
+    id*: uint
 
     when defined(chronosStackTrace):
       errorStackTrace*: StackTrace
@@ -78,8 +78,8 @@ type
     tail*: FutureBase
     count*: uint
 
-var currentID* {.threadvar.}: uint64
-currentID = 0'u64
+var currentID* {.threadvar.}: uint
+currentID = 0'u
 
 when defined(chronosFutureTracking):
   var futureList* {.threadvar.}: FutureList
diff --git a/tests/testutils.nim b/tests/testutils.nim
index 3e01f78a9..67a59ab3b 100644
--- a/tests/testutils.nim
+++ b/tests/testutils.nim
@@ -59,8 +59,8 @@ suite "Asynchronous utilities test suite":
       fut3.cancel()
       poll()
       check:
-        getCount() == 0'u64
-        pendingFuturesCount() == 0'u64
+        getCount() == 0'u
+        pendingFuturesCount() == 0'u
     else:
       skip()
 
@@ -71,17 +71,17 @@ suite "Asynchronous utilities test suite":
 
       var fut = simpleProc()
       check:
-        getCount() == 2'u64
-        pendingFuturesCount() == 2'u64
+        getCount() == 2'u
+        pendingFuturesCount() == 2'u
 
       waitFor fut
       check:
-        getCount() == 1'u64
-        pendingFuturesCount() == 1'u64
+        getCount() == 1'u
+        pendingFuturesCount() == 1'u
 
       poll()
       check:
-        getCount() == 0'u64
-        pendingFuturesCount() == 0'u64
+        getCount() == 0'u
+        pendingFuturesCount() == 0'u
     else:
       skip()