From 2337316fb18cb9b11378d6a1677fc429443e8a1b Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Sat, 22 Apr 2017 21:15:24 -0700
Subject: [PATCH] In substring, only return arg string if it's in NFC.

---
 src/runtime/ustring.scm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/runtime/ustring.scm b/src/runtime/ustring.scm
index bfbcfb556..b84c3a5ab 100644
--- a/src/runtime/ustring.scm
+++ b/src/runtime/ustring.scm
@@ -387,7 +387,7 @@ USA.
     (if (and (fix:= start 0)
 	     (fix:= end len)
 	     (not (slice? string))
-	     (not (ustring-mutable? string)))
+	     (ustring-in-nfc? string))
 	string
 	(translate-slice string start end
 	  (lambda (string start end)
-- 
2.25.1