diff --git a/test/test-traversal-1.rkt b/test/test-traversal-1.rkt
index 7284760..2775468 100644
--- a/test/test-traversal-1.rkt
+++ b/test/test-traversal-1.rkt
@@ -1,6 +1,6 @@
 #lang type-expander
 
-(require "../traversal.hl.rkt"
+(require "traversal-util.rkt" ;"../traversal.hl.rkt"
          "ck.rkt")
 
 (define-type Foo (Listof String))
diff --git a/test/test-traversal-2.rkt b/test/test-traversal-2.rkt
index 1c4c54d..8d3296f 100644
--- a/test/test-traversal-2.rkt
+++ b/test/test-traversal-2.rkt
@@ -1,6 +1,6 @@
 #lang typed/racket
 
-(require "../traversal.hl.rkt"
+(require "traversal-util.rkt" ;"../traversal.hl.rkt"
          type-expander
          phc-adt
          "ck.rkt"
diff --git a/test/traversal-util.rkt b/test/traversal-util.rkt
new file mode 100644
index 0000000..7aef472
--- /dev/null
+++ b/test/traversal-util.rkt
@@ -0,0 +1,22 @@
+#lang typed/racket
+(require (for-syntax syntax/parse
+                     syntax/parse/experimental/template
+                     type-expander/expander)
+         "../traversal.hl.rkt")
+
+(provide define-fold)
+
+(define-syntax define-fold
+  (syntax-parser
+    [(_ _function-name:id
+        _type-name:id
+        whole-type:type
+        _type-to-replaceᵢ:type ...)
+     (with-folds
+      (λ ()
+        (template
+         (begin
+           (define-type _type-name
+             (∀-replace-in-type whole-type _type-to-replaceᵢ ...))
+           (define _function-name
+             (λ-replace-in-instance whole-type _type-to-replaceᵢ ...))))))]))
\ No newline at end of file
diff --git a/traversal.hl.rkt b/traversal.hl.rkt
index 91662c9..2ffb573 100644
--- a/traversal.hl.rkt
+++ b/traversal.hl.rkt
@@ -389,7 +389,7 @@ where @racket[foldl-map] is defined as:
                 (for-meta 2 phc-toolkit/untyped)
                 (for-meta 2 syntax/parse))
 
-       (provide define-fold
+       (provide with-folds
                 (for-syntax replace-in-instance)
                 (for-syntax replace-in-type))
        <foldl-map>