diff --git a/lib/srfi/231/test.sld b/lib/srfi/231/test.sld
index 94962089..794b5627 100644
--- a/lib/srfi/231/test.sld
+++ b/lib/srfi/231/test.sld
@@ -2982,6 +2982,12 @@
         (test-error
          (array-tile (make-array (make-interval '#(0 0) '#(10 10)) list)
                      '#(10)))
+        (test-assert
+         (array-tile (make-array (make-interval '#(0 0) '#(10 10)) list)
+                     '#(10 20)))
+        (test-error
+         (array-tile (make-array (make-interval '#(0 0) '#(10 10)) list)
+                     '#(-10 20)))
 
         (let* ((TA '(( 1  2  3  4  5  6)
                      ( 7  8  9 10 11 12)
diff --git a/lib/srfi/231/transforms.scm b/lib/srfi/231/transforms.scm
index a53ac724..ae081b43 100644
--- a/lib/srfi/231/transforms.scm
+++ b/lib/srfi/231/transforms.scm
@@ -160,7 +160,7 @@
   (assert
    (vector-every (lambda (s len)
                    (if (exact-integer? s)
-                       (<= s len)
+                       (positive? s)
                        (= (vector-fold + 0 s) len)))
                  sizes
                  (interval-widths (array-domain array))))