1 files changed, 19 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/watchtower/bug-1871949.js b/js/src/jit-test/tests/watchtower/bug-1871949.js
new file mode 100644
index 0000000000..9b8b277b36
--- /dev/null
+++ b/js/src/jit-test/tests/watchtower/bug-1871949.js
@@ -0,0 +1,19 @@
+function getLogString(obj) {
+    let log = getWatchtowerLog();
+    return log.map(item => {
+        assertEq(item.object, obj);
+        if (typeof item.extra === "symbol") {
+            item.extra = "<symbol>";
+        }
+        return item.kind + (item.extra ? ": " + item.extra : "");
+    }).join("\n");
+}
+
+const entry = cacheEntry("");
+addWatchtowerTarget(entry);
+evaluate(entry, { "saveIncrementalBytecode": true });
+let log = getLogString(entry);
+
+// Nothing is logged for the manipulation of reserved slots, as we
+// lack infrastructure to track them thus far.
+assertEq(log.length, 0);