Feature request: Opaque/nominal types

The problem

It often happens that library functions return objects the type of which is an implementation detail. For example an identifier may be an integer but could suddenly be changed to a string, and the client code shouldn't fail because of that.

Safely typing such an identifier in LLS is currently impossible:

• typing it as integer depends on a potentially unstable implementation detail
• typing it as any is unsound

In other words, structural typing fails when the structure isn't stable or known.

Feature request

An annotations that declares a completely opaque/nominal type. It could be --@opaque typename, --@alias typename without any arguments, or anything else. Values belonging of such a type cannot be inspected in any way and can only be passed around. Values of different opaque types cannot be mixed up (so this is stronger than unknown in typescript)

ファイル、テスト、エントリポイントは指定されていません。まず、エイリアスと不明な型に関するアノテーションおよび型チェックのコードを見つけ、次に値がどのように検査または混在されるかを追跡してください。要求された動作をカバーするテストがあり、language server が受け渡しだけ可能な個別の不透明型をサポートすれば完了です。