From 233c9b8f508d07fb470c4b7567b11cafc9f1456f Mon Sep 17 00:00:00 2001
From: Ryan Culpepper <ryanc@racket-lang.org>
Date: Sun, 12 Aug 2018 00:52:58 +0200
Subject: [PATCH] syntax/parse: fix abstract failure pattern analysis

---
 racket/collects/syntax/parse/private/rep-patterns.rkt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/racket/collects/syntax/parse/private/rep-patterns.rkt b/racket/collects/syntax/parse/private/rep-patterns.rkt
index 2f8891ada5..28254b8075 100644
--- a/racket/collects/syntax/parse/private/rep-patterns.rkt
+++ b/racket/collects/syntax/parse/private/rep-patterns.rkt
@@ -458,8 +458,8 @@ A RepConstraint is one of
 (define AF-POST 2)  ;; can fail with progress >= POST
 (define AF-ANY  3)  ;; can fail with progress either < or >= POST
 
-;; AF-nz? : AbsFail -> {0, 1}
-(define (AF-nz? af) (if (= af AF-NONE) 0 1))
+;; AF-nz? : AbsFail -> Boolean
+(define (AF-nz? af) (not (= af AF-NONE)))
 
 ;; AF<? : AbsFail AbsFail -> Boolean
 ;; True if every failure in af1 has strictly less progress than any failure in af2.