diff --git a/module/language/cps/reify-primitives.scm b/module/language/cps/reify-primitives.scm
index 98cf85d1a..5fc86ccf5 100644
--- a/module/language/cps/reify-primitives.scm
+++ b/module/language/cps/reify-primitives.scm
@@ -201,34 +201,14 @@
   (wrap-unary cps k src 's64->u64 'u64->s64 'ulsh/immediate param a))
 
 (define (reify-lookup cps src mod-var name assert-bound? have-var)
-  (define (%lookup cps kbad k src mod-var name-var var assert-bound?)
-    (if assert-bound?
-        (with-cps cps
-          (letv val)
-          (letk kcheck
-                ($kargs ('val) (val)
-                  ($branch k kbad src 'undefined? #f (val))))
-          (letk kref
-                ($kargs () ()
-                  ($continue kcheck src
-                    ($primcall 'scm-ref/immediate '(box . 1) (var)))))
-          ($ (%lookup kbad kref src mod-var name-var var #f)))
-        (with-cps cps
-          (letk kres
-                ($kargs ('var) (var)
-                  ($branch kbad k src 'heap-object? #f (var))))
-          (build-term
-            ($continue kres src
-              ($primcall 'module-variable #f (mod-var name-var)))))))
-  (define %unbound
-    #(unbound-variable #f "Unbound variable: ~S"))
   (with-cps cps
     (letv name-var var)
-    (let$ good (have-var var))
-    (letk kgood ($kargs () () ,good))
-    (letk kbad ($kargs () () ($throw src 'throw/value %unbound (name-var))))
-    (let$ body (%lookup kbad kgood src mod-var name-var var assert-bound?))
-    (letk klookup ($kargs ('name) (name-var) ,body))
+    (let$ body (have-var var))
+    (letk kres ($kargs ('var) (var) ,body))
+    (letk klookup ($kargs ('name) (name-var)
+                    ($continue kres src
+                      ($primcall (if assert-bound? 'lookup-bound 'lookup) #f
+                                 (mod-var name-var)))))
     (build-term ($continue klookup src ($const name)))))
 
 (define (reify-resolve-module cps k src module public?)
diff --git a/module/language/tree-il/compile-cps.scm b/module/language/tree-il/compile-cps.scm
index d75807dec..703e9fd5f 100644
--- a/module/language/tree-il/compile-cps.scm
+++ b/module/language/tree-il/compile-cps.scm
@@ -1401,36 +1401,16 @@
     scope-id))
 
 (define (toplevel-box cps src name bound? have-var)
-  (define %unbound
-    #(unbound-variable #f "Unbound variable: ~S"))
   (match (current-topbox-scope)
     (#f
      (with-cps cps
        (letv mod name-var box)
-       (letk kbad ($kargs () () ($throw src 'throw/value %unbound (name-var))))
-       (let$ body
-             ((if bound?
-                  (lambda (cps)
-                    (with-cps cps
-                      (letv val)
-                      (let$ body (have-var box))
-                      (letk kdef ($kargs () () ,body))
-                      (letk ktest ($kargs ('val) (val)
-                                    ($branch kdef kbad src
-                                      'undefined? #f (val))))
-                      (build-term
-                        ($continue ktest src
-                          ($primcall 'scm-ref/immediate
-                                     '(box . 1) (box))))))
-                  (lambda (cps)
-                    (with-cps cps
-                      ($ (have-var box)))))))
-       (letk ktest ($kargs () () ,body))
-       (letk kbox ($kargs ('box) (box)
-                    ($branch kbad ktest src 'heap-object? #f (box))))
+       (let$ body (have-var box))
+       (letk kbox ($kargs ('box) (box) ,body))
        (letk kname ($kargs ('name) (name-var)
                      ($continue kbox src
-                       ($primcall 'module-variable #f (mod name-var)))))
+                       ($primcall (if bound? 'lookup-bound 'lookup) #f
+                                  (mod name-var)))))
        (letk kmod ($kargs ('mod) (mod)
                     ($continue kname src ($const name))))
        (build-term