#26925 only works at top-level: ```js (function () { function Brunch(children) { this.parent = null; } Brunch.prototype = { removeInner: function(at, n) { this.collapse(); }, collapse: function() { }, }; }); ``` **Expected behavior:** No error on `this.collapse` and `this: Brunch & { removeInner, collapse }` **Actual behavior:** Error on `this.collapse` and `this: Brunch`.