diff --git a/lib/pure/asyncmacro.nim b/lib/pure/asyncmacro.nim
index 3c8e593d5eb0d..926c6d6128a45 100644
--- a/lib/pure/asyncmacro.nim
+++ b/lib/pure/asyncmacro.nim
@@ -221,6 +221,7 @@ proc asyncSingleProc(prc: NimNode): NimNode =
   elif returnType.kind == nnkEmpty:
     baseType = returnType
   else:
+    baseType = nil
     verifyReturnType(repr(returnType), returnType)
 
   let futureVarIdents = getFutureVarIdents(prc.params)