From 0497c0742ff537b0e6c6bc133ef3921d025e4349 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannhorn@googlemail.com>
Date: Sun, 27 Mar 2011 19:46:44 +0200
Subject: [PATCH 1/3] fixes #1099: instead of nothing, compile to false

"if a in []"
---
 lib/nodes.js     | 3 +++
 src/nodes.coffee | 1 +
 2 files changed, 4 insertions(+)

diff --git a/lib/nodes.js b/lib/nodes.js
index 7b2ccd5e..4d956795 100644
--- a/lib/nodes.js
+++ b/lib/nodes.js
@@ -1719,6 +1719,9 @@
         }
         return _results;
       }).call(this);
+      if (tests.length === 0) {
+        return 'false';
+      }
       tests = tests.join(cnj);
       if (o.level < LEVEL_OP) {
         return tests;
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 99370609..4c43430b 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -1340,6 +1340,7 @@ exports.In = class In extends Base
     [cmp, cnj] = if @negated then [' !== ', ' && '] else [' === ', ' || ']
     tests = for item, i in @array.base.objects
       (if i then ref else sub) + cmp + item.compile o, LEVEL_OP
+    return 'false' if tests.length is 0
     tests = tests.join cnj
     if o.level < LEVEL_OP then tests else "(#{tests})"
 

From 9d72208d9e6a0bb14ab5756dc6161ccc6f060b18 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannhorn@googlemail.com>
Date: Sun, 27 Mar 2011 21:35:29 +0200
Subject: [PATCH 2/3] added a test (issue #1099)

---
 test/operators.coffee | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/test/operators.coffee b/test/operators.coffee
index 97ea24eb..39768e92 100644
--- a/test/operators.coffee
+++ b/test/operators.coffee
@@ -184,6 +184,9 @@ test "#768: `in` should preserve evaluation order", ->
   ok a() not in [b(),c()]
   eq 3, share
 
+test "#1099: empty array after `in` should compile to `false`", ->
+  eq 5 in [], false
+
 
 # Chained Comparison
 

From f03bcc24add88611af0e24f7e80ee39622195893 Mon Sep 17 00:00:00 2001
From: Michael Ficarra <github@michael.ficarra.me>
Date: Sun, 27 Mar 2011 23:42:49 -0400
Subject: [PATCH 3/3] enhanced tests for #1099 fix

---
 test/operators.coffee | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/operators.coffee b/test/operators.coffee
index 39768e92..87a0a6f5 100644
--- a/test/operators.coffee
+++ b/test/operators.coffee
@@ -185,7 +185,8 @@ test "#768: `in` should preserve evaluation order", ->
   eq 3, share
 
 test "#1099: empty array after `in` should compile to `false`", ->
-  eq 5 in [], false
+  eq 1, [5 in []].length
+  eq false, do -> return 0 in []
 
 
 # Chained Comparison