diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
index 7726f2f9..5e235433 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/infer-unit.rkt
@@ -311,12 +311,14 @@
                    [new-s-arr (make-arr (append ss new-tys) s #f (cons s-dty dbound) null)]
                    [new-cset (cgen/arr V (append vars X) Y new-s-arr t-arr)])
               (move-vars+rest-to-dmap new-cset dbound vars #:exact #t))]
-           [else
+           [(= (length ss) (length ts))
             ;; the simple case
             (let* ([arg-mapping (cgen/list V X Y (extend ss ts t-rest) ss)]
                    [darg-mapping (move-rest-to-dmap (cgen V (cons dbound X) Y t-rest s-dty) dbound #:exact #t)]
                    [ret-mapping (cg s t)])
-              (cset-meet* (list arg-mapping darg-mapping ret-mapping)))])]
+              (cset-meet* (list arg-mapping darg-mapping ret-mapping)))]
+           [else
+             (fail! s-arr t-arr)])]
     [(_ _) (fail! s-arr t-arr)]))
 
 (define/cond-contract (cgen/flds V X Y flds-s flds-t)
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/subtype-tests.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/subtype-tests.rkt
index 9af8995f..5628f773 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/subtype-tests.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/unit-tests/subtype-tests.rkt
@@ -244,6 +244,10 @@
    [(-polydots (a) (->... (list) (a a) (make-ListDots a 'a)))
     (-polydots (b a) (->... (list b) (a a) (-pair b (make-ListDots a 'a))))]
 
+   [FAIL
+    (-polydots (c a b) (->... (list (->... (list a) (b b) c) (-vec a)) ((-vec b) b) (-vec c)))
+    (->* (list (->* (list) -Symbol -Symbol)) (-vec -Symbol) (-vec -Symbol))]
+
    [(-> Univ -Boolean : (-FS (-filter -Symbol 0) (-not-filter -Symbol 0)))
     (-> Univ -Boolean : -top-filter)]
    [(-> Univ -Boolean : -bot-filter)