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

Comienza estudiando el ejemplo de inferencia genérica del issue y revisando los issues referenciados #9366, #3423, #25092, #26951, #25826 y #10247. Recopila casos de uso validados y evalúa el coste y el beneficio de cambiar el algoritmo de inferencia; se considera terminado cuando se haya producido una dirección de diseño fundamentada, en lugar de un cambio de código acotado.