1 files changed, 16 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/jaeger/bug639808.js b/js/src/jit-test/tests/jaeger/bug639808.js
new file mode 100644
index 0000000000..bf6b16c3d1
--- /dev/null
+++ b/js/src/jit-test/tests/jaeger/bug639808.js
@@ -0,0 +1,16 @@
+function f() {
+    var x = 1.23;
+    var y = [].length;
+    x = ++y;
+    y - 1;
+}
+f();
+
+function g(q) {
+    var x = 1.23;
+    var y = [].length;
+    x = ++y;
+    if (q)
+      assertEq(y + 5, 6);
+}
+g(1);