diff --git a/library/core/src/ptr/unique.rs b/library/core/src/ptr/unique.rs
index edc1dc941cbc1..8a282c86a7868 100644
--- a/library/core/src/ptr/unique.rs
+++ b/library/core/src/ptr/unique.rs
@@ -284,8 +284,8 @@ mod verify {
     }
 
     // pub const fn cast<U>(self) -> Unique<U>
-    #[kani::proof_for_contract(Unique::cast<U>)]
-    pub fn check_cast<U>() {
+    #[kani::proof]
+    pub fn check_cast() {
         let mut x : i32 = kani::any();
         let xptr = &mut x;
         unsafe {