The Tor Browser / file revision

 this.name = "outer";

 var sb = evalcx('');

 sb.name = "inner";

 sb.parent = this;

 function f() { return this.name; }

 f.notMuchTodo = '42';

 assertEq(evalcx('{\n' +

                 '  let f = parent.f;\n' +

                 '  let name = "block";\n' +

                 '  (function () {\n' +

                 '    eval(f.notMuchTodo);\n' + // reify Block

                 '    var s = "";\n' +

                 '    for (i = 0; i < 10; ++i)\n' +

                 '      s += f();\n' +

                 '    return s;\n' +

                 '  })();\n' +

                 '}',

                 sb),

 	 "outerouterouterouterouterouterouterouterouterouter");