From 2fcdd7c29223b4a0d1491319716e7d461c15fbb2 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sat, 28 Dec 2019 08:05:22 -0600
Subject: [PATCH] cs: improve `equal?`-based immutable hash

Check leaf hash code before a more general (and potentially much
slower) equality check.
---
 racket/src/cs/rumble/intmap.ss | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/racket/src/cs/rumble/intmap.ss b/racket/src/cs/rumble/intmap.ss
index 36bf719363..ea2c181f5a 100644
--- a/racket/src/cs/rumble/intmap.ss
+++ b/racket/src/cs/rumble/intmap.ss
@@ -84,7 +84,8 @@
               (loop (Br-right t)))]
 
          [(Lf? t)
-          (if (key=? et key (Lf-key t))
+          (if (and (fx= h (Lf-hash t))
+                   (key=? et key (Lf-key t)))
               (with-leaf t)
               default)]