michael@0: // Arrow functions can have primitive |this| values.
michael@0: 
michael@0: Number.prototype.foo = function() {
michael@0:     "use strict";
michael@0:     return () => this;
michael@0: }
michael@0: 
michael@0: for (var i=0; i<5; i++) {
michael@0:     var n = i.foo()();
michael@0:     assertEq(typeof n, "number");
michael@0:     assertEq(n, i);
michael@0: }