1 files changed, 15 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/str-atom-cache-extensible.js b/js/src/jit-test/tests/basic/str-atom-cache-extensible.js
new file mode 100644
index 0000000000..bee8f13847
--- /dev/null
+++ b/js/src/jit-test/tests/basic/str-atom-cache-extensible.js
@@ -0,0 +1,15 @@
+// Create an extensible string.
+var extensible = "foo".repeat(50);
+extensible += "bar";
+extensible.indexOf("X");
+
+// Ensure it's in the StringToAtomCache.
+var obj = {};
+obj[extensible] = 1;
+
+// Make it a dependent string.
+var other = extensible + "baz";
+other.indexOf("X");
+
+// Must still be in the cache.
+obj[extensible] = 1;