1 files changed, 19 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Frame-this-07.js b/js/src/jit-test/tests/debug/Frame-this-07.js
new file mode 100644
index 0000000000..50d938f46c
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Frame-this-07.js
@@ -0,0 +1,19 @@
+// Frame.this can be marked as optimized-out in some cases. Here we call an
+// arrow function but its enclosing function is no longer live, so it's
+// impossible to recover its missing 'this' binding.
+var g = newGlobal({newCompartment: true});
+g.eval("x = 4");
+g.eval("var foo = function() { return () => 1; }; var arrow = foo.call(3);");
+var dbg = new Debugger(g);
+var log = "";
+dbg.onEnterFrame = function (frame) {
+    if (frame.type === "eval")
+	return;
+    assertEq(frame.type, "call");
+    assertEq(frame.this.optimizedOut, true);
+    frame.eval("try { print(this.x); } catch(e) { exc = e; }");
+    assertEq(typeof g.exc, "object");
+    log += "d";
+};
+g.eval("arrow();");
+assertEq(log, "d");