diff --git a/js-assembler/runtime-src/runtime.js b/js-assembler/runtime-src/runtime.js
index feb4874..2acae92 100644
--- a/js-assembler/runtime-src/runtime.js
+++ b/js-assembler/runtime-src/runtime.js
@@ -834,7 +834,7 @@
     };
 
     var checkedAdd = function(M, x, y) {
-        var sum;
+        var sum, i;
         // fast path optimization: binop addition on fixnums
         if (arguments.length === 3) {
             if (typeof(x) === 'number' && typeof(y) === 'number') {
diff --git a/version.rkt b/version.rkt
index bb38fa3..71deeb4 100644
--- a/version.rkt
+++ b/version.rkt
@@ -7,4 +7,4 @@
 (provide version)
 (: version String)
 
-(define version "1.158")
+(define version "1.159")