TS crash on some cyclic thunks

[ssalbdivad]

With the changes made following 2.0.0-beta.2, the following type now leads to a TS crash:

const $ = scope({
  filename: "0<string<255",
  file: {
    type: "'file'",
    name: "filename",
  },
  directory: {
    type: "'directory'",
    name: "filename",
    children: () =>
      $.type("root[]").narrow((v, ctx) => {
        if (new Set(v.map((f) => f.name)).size !== v.length)
          return ctx.mustBe("names must be unique in a directory");

        return true;
      }),
  },
  root: "file|directory",
});

const types = $.export();

The equivalent type with a thunk implementation is fine, but it would be good to know the exact change/trade off that led to a problem with this kind of cyclic thunk, and perhaps log an issue with the Ts team for the crash.