diff --git a/collects/unstable/dirs.rkt b/collects/unstable/dirs.rkt
deleted file mode 100644
index b651025a7e..0000000000
--- a/collects/unstable/dirs.rkt
+++ /dev/null
@@ -1,72 +0,0 @@
-#lang racket/base
-
-;; This file needs to be deleted -- it is now superseded by
-;; `setup/path-relativize'.
-
-;; Unstable library by: Carl Eastlund <cce@ccs.neu.edu>
-;; intended for use in racket/contract, so don't try to add contracts!
-
-(require setup/path-relativize
-         setup/dirs
-         (only-in planet/config [CACHE-DIR find-planet-dir]))
-
-(provide path->directory-relative-string
-         library-relative-directories
-         setup-relative-directories)
-
-(define library-relative-directories
-  (list (cons find-collects-dir 'collects)
-        (cons find-user-collects-dir 'user-collects)
-        (cons find-planet-dir 'planet)))
-
-(define setup-relative-directories
-  (list (cons find-collects-dir #f)
-        (cons find-user-collects-dir 'user)
-        (cons find-planet-dir 'planet)))
-
-(define (path->directory-relative-string
-         path
-         #:default [default (if (path? path) (path->string path) path)]
-         #:dirs [dirs library-relative-directories])
-
-  (unless (path-string? path)
-    (error 'path->directory-relative-string
-      "expected a path or a string (first argument); got: ~e" path))
-
-  (unless (and (list? dirs) (andmap pair? dirs))
-    (error 'path->directory-relative-string
-      "expected an association list (#:dirs keyword argument); got: ~e" dirs))
-
-  (let/ec return
-
-    (when (complete-path? path)
-      (for ([dir-entry (in-list dirs)])
-        (define find-dir (car dir-entry))
-        (define dir-name (cdr dir-entry))
-
-        (unless (and (procedure? find-dir)
-                     (procedure-arity-includes? find-dir 0))
-          (error 'path->directory-relative-string
-            "expected keys in association list to be thunks (~a); got: ~e"
-            "#:dirs keyword argument"
-            find-dir))
-
-        (let ()
-
-          (define-values [ path->relative relative->path ]
-            (make-relativize find-dir
-                             'relative
-                             'path->relative
-                             'relative->path))
-          (define exploded
-            (with-handlers ([exn:fail? (lambda (e) #f)])
-              (path->relative path)))
-          (when (list? exploded)
-            (let ([relative (path->string
-                             (apply build-path
-                               (map bytes->path-element (cdr exploded))))])
-              (return
-               (if dir-name
-                 (format "<~a>/~a" dir-name relative)
-                 relative)))))))
-    default))