From 9c783616cc46eeb907c93b272dd6a6f36df9e204 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Tue, 12 Jul 2016 09:05:51 +0200
Subject: [PATCH] Reduce-right not limited by stack

* module/srfi/srfi-1.scm (reduce-right): Avoid blowing out the stack.
  Fixes #17485.
---
 module/srfi/srfi-1.scm | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/module/srfi/srfi-1.scm b/module/srfi/srfi-1.scm
index d2531b59d..670a3ae7d 100644
--- a/module/srfi/srfi-1.scm
+++ b/module/srfi/srfi-1.scm
@@ -557,10 +557,7 @@ then that's the return value."
 F is on two elements from LST, rather than one element and a given
 initial value.  If LST is empty, RIDENTITY is returned.  If LST
 has just one element then that's the return value."
-  (check-arg procedure? f reduce)
-  (if (null? lst)
-      ridentity
-      (fold-right f (last lst) (drop-right lst 1))))
+  (reduce f ridentity (reverse lst)))
 
 (define map
   (case-lambda