From f5c6d808afb01e4c5f8192ef324bfd49b26b30c6 Mon Sep 17 00:00:00 2001
From: Sam Tobin-Hochstadt <samth@racket-lang.org>
Date: Mon, 24 May 2010 23:29:17 -0700
Subject: [PATCH] Test for former bug. Closes PR 10470.

original commit: 775e1b06a577a1306ab50de05174a6e26f944d40
---
 collects/tests/typed-scheme/succeed/pr10470.rkt | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 collects/tests/typed-scheme/succeed/pr10470.rkt

diff --git a/collects/tests/typed-scheme/succeed/pr10470.rkt b/collects/tests/typed-scheme/succeed/pr10470.rkt
new file mode 100644
index 00000000..bfc21cc2
--- /dev/null
+++ b/collects/tests/typed-scheme/succeed/pr10470.rkt
@@ -0,0 +1,15 @@
+(module pr10470 typed-scheme
+
+  (define-type-alias (Memo alpha) (U (Option alpha) (-> (Option alpha))))
+
+  (define-struct: table ([val : (Memo Number)]) #:mutable)
+
+  (: f (table -> (Option Number)))
+  (define (f tab)
+    (let ([proc-or-num (table-val tab)])
+      (cond
+        [(procedure? proc-or-num)
+         (let ([result (proc-or-num)])
+           (set-table-val! tab result)
+           result)]
+        [else proc-or-num]))))
\ No newline at end of file