From 5fda25a42e1386e46569ccf606c4922bfb1634c2 Mon Sep 17 00:00:00 2001
From: Sam Caldwell <samc@ccs.neu.edu>
Date: Fri, 17 May 2019 10:34:33 -0400
Subject: [PATCH] more hash operations

---
 racket/typed/hash.rkt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/racket/typed/hash.rkt b/racket/typed/hash.rkt
index 86ae599..777f230 100644
--- a/racket/typed/hash.rkt
+++ b/racket/typed/hash.rkt
@@ -5,9 +5,11 @@
          hash
          hash-set
          hash-ref
+         (typed-out [[hash-ref/failure- : (∀ (K V) (→fn (Hash K V) K V V))]
+                     hash-ref/failure])
          hash-has-key?
          hash-update
-         (typed-out [[hash-update/failure- : (∀ (K V) (→fn (Hash K V) K (→fn V V) (→fn V) (Hash K V)))]
+         (typed-out [[hash-update/failure- : (∀ (K V) (→fn (Hash K V) K (→fn V V) V (Hash K V)))]
                      hash-update/failure])
          hash-remove
          hash-map
@@ -72,6 +74,9 @@
   ;; TODO - hash-union with #:combine
   )
 
+(define- (hash-ref/failure- h k err)
+  (#%app- hash-ref- h k err))
+
 (define- (hash-update/failure- h k u err)
   (#%app- hash-update- h k u err))