src/third_party/mozjs-45/js/src/jit-test/tests/debug/gc-09.2.js

// Bug 717104 - Unreachable debuggee globals should not keep their debuggers
// alive. The loop is to defeat conservative stack scanning; if the same stack
// locations are used each time through the loop, at least three of the
// debuggers should be collected.
//
// This is a slight modification of gc-09.js, which contains a cycle.

for (var i = 0; i < 4; i++) {
    var g = newGlobal();
    var dbg = new Debugger(g);
    dbg.onDebuggerStatement = function () { throw "FAIL"; };
    dbg.o = makeFinalizeObserver();
}

gc();
assertEq(finalizeCount() > 0, true);