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

Beginne damit, das generische Inferenzbeispiel im Issue zu untersuchen und die referenzierten Issues #9366, #3423, #25092, #26951, #25826 und #10247 zu prüfen. Sammle validierte Anwendungsfälle und bewerte Kosten und Nutzen einer Änderung des Inferenzalgorithmus; abgeschlossen bedeutet, eine fundierte Designrichtung statt einer begrenzten Codeänderung zu erarbeiten.