diff --git a/kernel/src/objects/untyped.rs b/kernel/src/objects/untyped.rs
index fecca9b..89d7ef0 100644
--- a/kernel/src/objects/untyped.rs
+++ b/kernel/src/objects/untyped.rs
@@ -89,7 +89,7 @@ impl UntypedCap<'_> {
         slots
             .iter()
             .any(|cte| NullCap::try_from(cte).is_err())
-            .then_ok((), SysError::CapTypeMismatch)?;
+            .else_ok((), SysError::CapTypeMismatch)?;
 
         // Start allocating from free_offset
         // Notice: in vallina seL4, it will check whether there are child nodes,