diff --git a/stdlib/maybe.rkt b/stdlib/maybe.rkt
index d598f46..7f9b5ff 100644
--- a/stdlib/maybe.rkt
+++ b/stdlib/maybe.rkt
@@ -8,7 +8,8 @@
 
 (module+ test
   (require rackunit "bool.rkt")
-  (check-equal?
+  ;; Disabled until #22 fixed
+  #;(check-equal?
     (case* Maybe Type (some Bool true) (Bool)
       (lambda* (A : Type) (x : (Maybe A)) A)
       [(none (A : Type)) IH: ()
diff --git a/stdlib/nat.rkt b/stdlib/nat.rkt
index 9f4c114..ebb2307 100644
--- a/stdlib/nat.rkt
+++ b/stdlib/nat.rkt
@@ -47,6 +47,7 @@
   (check-equal? (nat-equal? z (s z)) false)
   (check-equal? (nat-equal? (s z) (s z)) true))
 
+#| TODO: Disabled until #20 fixed
 (define (even? (n : Nat))
   (elim Nat Type (lambda (x : Nat) Bool)
         false
@@ -80,3 +81,4 @@
   (check-equal?
     (odd? (s (s (s z))))
     true))
+|#
diff --git a/stdlib/prop.rkt b/stdlib/prop.rkt
index 998eaa2..5422c53 100644
--- a/stdlib/prop.rkt
+++ b/stdlib/prop.rkt
@@ -62,6 +62,7 @@
 
 (qed thm:proj2 proof:proj2)
 
+#| TODO: Disabled until #22 fixed
 (data Or : (forall* (A : Type) (B : Type) Type)
   (left : (forall* (A : Type) (B : Type) (a : A) (Or A B)))
   (right : (forall* (A : Type) (B : Type) (b : B) (Or A B))))
@@ -79,6 +80,7 @@
       A A c)))
 
 (qed thm:A-or-A proof:A-or-A)
+|#
 
 (data == : (forall* (A : Type) (x : A) (-> A Type))
   (refl : (forall* (A : Type) (x : A) (== A x x))))