Design Meeting Notes, 2026-09-15

# Better Type Inference Self-Referential Values

- https://github.com/microsoft/TypeScript/issues/64192
- https://github.com/microsoft/TypeScript/issues/62180
- https://github.com/microsoft/TypeScript/issues/62181
- https://github.com/microsoft/TypeScript/pull/64172
- https://github.com/microsoft/TypeScript/pull/64248

```ts
const Category = z.object({
get subcategories() {
// ~~~~~~~~~~~~~
// Subcategory implicitly has type 'any' because of circular
// resolution.
return z.array(Category);
}
});
```

* Zod and similar libraries are motivation here.
* While processing the object literal, we normally defer return types for `get` accessors.
* But when validating the constraint, we start pulling on those very types.
* One idea: when we try to resolve a call that is already undergoing resolution, we say "don't check constraints".
* Why don't we disable constraint checking for all calls and do it in another pass?
* We're not always interested in just generating an error, we're often trying to grab the constraint for other information (e.g. if there's no candidates, we have to fix to the constraint).
* How does this affect overloads? Because this would affect how we choose overloads, right?
* Should not play in?
* Could we just return the original *uninstantiated* type parameter from the call when you detect this circularity?
* How would that work? Isn't that a type parameter leak?
* Yes, but the idea is there's an "outer" call and an "inner" call. The inner call would leak a type parameter (e.g. `T`) and the outer call would instantiate it after inference.
* Scary, but maybe!
* Outstanding PRs are likely not quite what we're looking for, but may have a PR prototyping these ideas soon.

Bắt đầu bằng cách đọc các issue được liên kết 64192, 62180 và 62181, sau đó xem xét các PR 64172 và 64248 để đánh giá những cách tiếp cận hiện có. Các ghi chú thảo luận một số thiết kế chưa được giải quyết cho suy luận kiểu vòng, overload, constraint và việc rò rỉ tham số kiểu, nhưng không xác định tệp, test hoặc tiêu chí hoàn thành.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.