From 9d541885eb118e18cd72f5572345dc2367b4bd5b Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 2 Jun 2010 01:36:42 -0700
Subject: [PATCH] Change %CANONICALIZE-SCALAR-VALUE-LIST to eliminate empty
 ranges.

---
 src/runtime/chrset.scm | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/runtime/chrset.scm b/src/runtime/chrset.scm
index ec7f0b086..2c39a7fa3 100644
--- a/src/runtime/chrset.scm
+++ b/src/runtime/chrset.scm
@@ -204,9 +204,14 @@ USA.
     high))
 
 (define (%canonicalize-scalar-value-list ranges)
-  ;; Sort ranges in order, then merge adjacent ranges.
+  ;; Sort ranges in order, delete empty ranges, then merge adjacent
+  ;; ranges.
   (if (pair? ranges)
-      (let ((ranges (sort ranges %range<?)))
+      (let ((ranges
+	     (filter! (lambda (range)
+			(fix:< (%range-start range)
+			       (%range-end range)))
+		      (sort ranges %range<?))))
 	(let loop
 	    ((start1 (%range-start (car ranges)))
 	     (end1 (%range-end (car ranges)))
-- 
2.25.1