diff --git a/compiler/compiler.rkt b/compiler/compiler.rkt
index 3d7fcac..e8fb23f 100644
--- a/compiler/compiler.rkt
+++ b/compiler/compiler.rkt
@@ -1887,7 +1887,7 @@
                           (build-list count (lambda: ([i : Natural])
                                               (make-EnvLexicalReference (+ i 
                                                                            (InstallValue-depth exp)
-                                                                           (sub1 count))
+                                                                           (ensure-natural (sub1 count)))
                                                                         (InstallValue-box? exp))))
                           (cons (make-Reg 'val) 
                                 (build-list (sub1 count) (lambda: ([i : Natural])
diff --git a/js-assembler/assemble-helpers.rkt b/js-assembler/assemble-helpers.rkt
index 1271dc6..be54418 100644
--- a/js-assembler/assemble-helpers.rkt
+++ b/js-assembler/assemble-helpers.rkt
@@ -185,8 +185,7 @@
                        (path->string val))]
               [(vector? val)
                (format "RT.makeVector([~a])"
-                       (string-join (for/list ([elt (vector->list val)])
-                                       (loop elt))
+                       (string-join (map loop (vector->list val)) 
                                     ","))]
               [(box? val)
                (format "RT.makeBox(~s)"