Fix character sets containing both ] and -.

scsh/rx/posixstr.scm

@@ -615,12 +615,12 @@
 	    (receive (new-loose new-ranges) (shrink-range-start (car ranges))
 	      (lp (append new-loose loose) (append new-ranges ranges) end-hyphen?)))
 
-	   ;; If both [ and - are in the loose char set,
+	   ;; If both ] and - are in the loose char set,
 	   ;; pull - out as special end-hypen.
 	   ((and (pair? loose)
 		 (pair? (cdr loose))
-		 (char=? (car loose) #\[)
-		 (char=? (car loose) #\-))
+		 (char=? (car loose) #\])
+		 (char=? (cadr loose) #\-))
 	    (lp (cons (car loose) (cddr loose)) ranges #t))
 
 	   ;; No change! Build the answer...
@@ -629,4 +629,5 @@
 				(apply string-append
 				       (map (lambda (r) (string (car r) #\- (cdr r)))
 					    ranges))
+				(if end-hyphen? "-" "")
 				"]"))))))))