1 files changed, 18 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/gc/bug-1520778.js b/js/src/jit-test/tests/gc/bug-1520778.js
new file mode 100644
index 0000000000..df72248983
--- /dev/null
+++ b/js/src/jit-test/tests/gc/bug-1520778.js
@@ -0,0 +1,18 @@
+// |jit-test| error: ReferenceError
+gczeal(0);
+setMarkStackLimit(1);
+var g = newGlobal({
+    newCompartment: true
+});
+var dbg = new Debugger;
+var gw = dbg.addDebuggee(g);
+dbg.onDebuggerStatement = function(frame) {
+  frame.environment.parent.getVariable('y')
+};
+g.eval(`
+  let y = 1;
+  g = function () { debugger; };
+  g();
+`);
+gczeal(9, 10);
+f4();