To write loops in TypeScript's type system, we have to use recursions, like we do in other purely functional programming languages. Meanwhile, we use [CPS](https://en.wikipedia.org/wiki/Continuation-passing_style) to implement continuations, which also introduces heavy recursion. However, TypeScript's type system is not meant for general purpose programming, and recursion has its limits.
In [src/compiler/checker.ts](https://raw.githubusercontent.com/microsoft/TypeScript/release-4.1/src/compiler/checker.ts), there is a hard-coded limit for type instantiation:
```typescript
if (instantiationDepth === 50 || instantiationCount >= 5000000) {
You may expect that there is an option somewhere that this limit can be configured, like `-ftemplate-depth=n` in gcc/clang. Unfortunately, there isn't, [and it's likely to stay that way](https://github.com/microsoft/TypeScript/pull/29602).
To workaround this limitation, we modify the code of `tsserver` or `tsc` in `node_modules` until the error no longer applies. Changing `instantiationDepth` to `1000` is sufficient to run the example above.