src/third_party/mozjs-45/js/src/jit-test/tests/saved-stacks/shared-parent-frames.js

// Test that parent frames are shared when the older portions of two stacks are
// the same.

let f1, f2;

function dos() {
  f1 = saveStack();
  f2 = saveStack();
}

(function uno() {
  dos();
}());


// Different youngest frames.
assertEq(f1 == f2, false);
// However the parents should be the same.
assertEq(f1.parent, f2.parent);