From bbb62da731324fdbb7ce1b42b5b07df164e25f40 Mon Sep 17 00:00:00 2001
From: Alex Knauth <alexander@knauth.org>
Date: Mon, 12 Sep 2016 09:17:57 -0400
Subject: [PATCH] fix type of non-empty-string? (#427)

fixes #426
---
 typed-racket-lib/typed-racket/base-env/base-env.rkt |  2 +-
 typed-racket-test/succeed/gh-issue-426.rkt          | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 typed-racket-test/succeed/gh-issue-426.rkt

diff --git a/typed-racket-lib/typed-racket/base-env/base-env.rkt b/typed-racket-lib/typed-racket/base-env/base-env.rkt
index 23acf765..fdafafca 100644
--- a/typed-racket-lib/typed-racket/base-env/base-env.rkt
+++ b/typed-racket-lib/typed-racket/base-env/base-env.rkt
@@ -177,7 +177,7 @@
            #:repeat? Univ #f
            -String)]
 
-[non-empty-string? (make-pred-ty -String)]
+[non-empty-string? (asym-pred Univ -Boolean (-PS (-is-type 0 -String) -tt))]
 [string-contains? (-> -String -String -Boolean)]
 [string-prefix? (-> -String -String -Boolean)]
 [string-suffix? (-> -String -String -Boolean)]
diff --git a/typed-racket-test/succeed/gh-issue-426.rkt b/typed-racket-test/succeed/gh-issue-426.rkt
new file mode 100644
index 00000000..44d9083d
--- /dev/null
+++ b/typed-racket-test/succeed/gh-issue-426.rkt
@@ -0,0 +1,12 @@
+#lang typed/racket
+
+;; Test for Github issue #426
+;; https://github.com/racket/typed-racket/issues/426
+
+(require racket/string typed/rackunit)
+
+(check-equal? (non-empty-string? "foo")            #true)
+(check-equal? (non-empty-string? "")               #false)
+(check-equal? (if (non-empty-string? "foo") 'A 'B) 'A)
+(check-equal? (if (non-empty-string? "")    'A 'B) 'B)
+