diff --git a/src/jonase/kibit/rules/arithmetic.clj b/src/jonase/kibit/rules/arithmetic.clj
index da64652..496102a 100644
--- a/src/jonase/kibit/rules/arithmetic.clj
+++ b/src/jonase/kibit/rules/arithmetic.clj
@@ -17,5 +17,6 @@
     (< ?x 0) (neg? ?x)
     
     (= ?x ?x)  true
-    (== ?x ?x) true})
+    (== ?x ?x) true
+    (zero? 0)  true})
 
diff --git a/src/jonase/kibit/rules/control_structures.clj b/src/jonase/kibit/rules/control_structures.clj
index 1d611b6..687385f 100644
--- a/src/jonase/kibit/rules/control_structures.clj
+++ b/src/jonase/kibit/rules/control_structures.clj
@@ -7,7 +7,10 @@
     (if (not ?x) ?y ?z) (if-not ?x ?y ?z)
     (when (not ?x) . ?y) (when-not ?x ?y)
     (if true ?x ?y) ?x
-    (when true . ?x) (do . ?x)}) ; Maybe this should be (do ?x)
+    (when true . ?x) (do . ?x)
+    (do ?x) ?x
+    (when-not true ?x) "removing this dead code"
+    (when false ?x) "removing this dead code"})
 
 (comment
   (when true