1 files changed, 23 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/gc/bug-1620221.js b/js/src/jit-test/tests/gc/bug-1620221.js
new file mode 100644
index 0000000000..d363dab3dd
--- /dev/null
+++ b/js/src/jit-test/tests/gc/bug-1620221.js
@@ -0,0 +1,23 @@
+function testStepping(script, expected) {
+    let g = newGlobal({newCompartment: true});
+    let f = g.eval(script);
+    let log = [];
+    function maybePause(frame) {
+        let line = frame.script.getOffsetLocation(frame.offset).lineNumber;
+        log.push(line);
+    }
+    let dbg = new Debugger(g);
+    dbg.onEnterFrame = frame => {
+        maybePause(frame);
+    };
+    f();
+}
+var g7 = newGlobal({newCompartment: true});
+g7.parent = this;
+g7.eval(`
+    Debugger(parent).onEnterFrame = function(frame) {
+        let v = frame.environment.getVariable('var0');
+    };
+`);
+testStepping("(function() {})");
+gc();