Meta-issue: Use Full Unification for Generic Inference?

Search Terms

unification generic inference

Suggestion

Today, TypeScript cannot retain or synthesize free type parameters during generic inference. This means code like this doesn't typecheck, when it should:

function identity<T>(arg: T) { return arg; }
function memoize<F extends (...args: unknown[]) => unknown>(fn: F): F { return fn; }
// memid: unknown => unknown
// desired: memid<T>(T) => T
const memid = memoize(identity);

Use Cases

Many functional programming patterns would greatly benefit from this.

The purpose of this issue is to gather use cases and examine the cost/benefit of using a different inference algorithm.

Examples

Haven't extensively researched these to validate that they require unification, but it's a start:

#9366
#3423
#25092
#26951 (design meeting notes with good examples)
#25826
#10247

まず、issue にあるジェネリック推論の例を調査し、参照されている issue #9366、#3423、#25092、#26951、#25826、#10247 を確認します。検証済みのユースケースを収集し、推論アルゴリズムを変更するコストとメリットを評価します。完了とは、限定的なコード変更ではなく、十分に検討された設計方針を作成することを意味します。