From 43863acd3666f03852dc6ce6489dd81ad43123e0 Mon Sep 17 00:00:00 2001
From: Sam Tobin-Hochstadt <samth@racket-lang.org>
Date: Thu, 27 Sep 2012 17:26:10 -0400
Subject: [PATCH] Test for appropriate predicates for invariant structs.

original commit: cab90c16d5514ac4c9dff70ebcaeb3dda75e0910
---
 .../typed-racket/succeed/structs-variance.rkt      | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 collects/tests/typed-racket/succeed/structs-variance.rkt

diff --git a/collects/tests/typed-racket/succeed/structs-variance.rkt b/collects/tests/typed-racket/succeed/structs-variance.rkt
new file mode 100644
index 00000000..b50972d7
--- /dev/null
+++ b/collects/tests/typed-racket/succeed/structs-variance.rkt
@@ -0,0 +1,14 @@
+#lang typed/racket
+
+(struct: (A) x ([f : (A -> A)]))
+(struct: (B) y ([f : (x B)]))
+
+(: f : (U Integer (y Integer)) -> Integer)
+(define (f v)
+  (if (y? v)
+      ((x-f (y-f v)) 0)
+      v))
+
+(f 17)
+
+(f (y (x (lambda: ([n : Integer]) (+ 2 n)))))