diff --git a/syndicate/skeleton.rkt b/syndicate/skeleton.rkt
index 17dfaa9..82d775d 100644
--- a/syndicate/skeleton.rkt
+++ b/syndicate/skeleton.rkt
@@ -154,13 +154,11 @@
 
 (define (term-matches-ctor-spec? term ctor-spec)
   (match ctor-spec
-    [(? number? arity)
-     (and (list? term) (= (length term) arity))]
-    [(cons label (? number? arity))
+    [(cons 'rec label)
      (and (non-object-struct? term)
-          (let ((t (struct->struct-type term)))
-            (and (equal? (struct-type-name t) label)
-                 (= (struct-type-constructor-arity t) arity))))]
+          (equal? (struct-type-name (struct->struct-type term)) label))]
+    ['arr
+     (list? term)]
     ['dict
      (hash? term)]))
 
@@ -180,8 +178,8 @@
            [(cons _selector table) table]))
        (define ctor-spec
          (match compound-pat
-           [(DCompound-rec label field-pats) (cons label (length field-pats))]
-           [(DCompound-arr item-pats) (length item-pats)]
+           [(DCompound-rec label field-pats) (cons 'rec label)]
+           [(DCompound-arr item-pats) 'arr]
            [(DCompound-dict _entries) 'dict]))
        (define (make-skeleton-node-with-cache)
          (define unfiltered (skeleton-continuation-cache (skeleton-node-continuation sk)))
@@ -250,16 +248,14 @@
       (define popped-stack (drop term-stack pop-count))
       (define old-top (car popped-stack))
       (define new-top (step-term old-top key))
-      (define entry (hash-ref table
-                              (cond [(non-object-struct? new-top)
-                                     (define t (struct->struct-type new-top))
-                                     (cons (struct-type-name t) (struct-type-constructor-arity t))]
-                                    [(list? new-top)
-                                     (length new-top)]
-                                    [(hash? new-top)
-                                     'dict]
-                                    [else #f])
-                              #f))
+      (define entry
+        (hash-ref table
+                  (cond [(non-object-struct? new-top) (cons 'rec (struct-type-name
+                                                                  (struct->struct-type new-top)))]
+                        [(list? new-top) 'arr]
+                        [(hash? new-top) 'dict]
+                        [else #f])
+                  #f))
       (when entry (walk-node! entry (cons new-top popped-stack))))))
 
 (define (add-term-to-skcont! skcont term)
@@ -344,7 +340,13 @@
     (step-term term key)))
 
 (define (step-term term key)
-  (cond [(non-object-struct? term) (vector-ref (struct->vector term) (+ key 1))]
-        [(list? term) (list-ref term key)]
-        [(hash? term) (hash-ref term key (void))]
-        [else (error 'apply-projection "Term representation not supported: ~v" term)]))
+  (cond [(non-object-struct? term)
+         (define v (struct->vector term))
+         (define k (+ key 1)) ;; skip the label
+         (if (>= k (vector-length v)) (void) (vector-ref v k))]
+        [(list? term)
+         (if (>= key (length term)) (void) (list-ref term key))]
+        [(hash? term)
+         (hash-ref term key (void))]
+        [else
+         (error 'apply-projection "Term representation not supported: ~v" term)]))