add a constraint for immutable types

say, i have a generic function that by design requires that its parameters may only take immutable arguments, i wish i could get such guarantee from TS by declaring my function as follows:

function doThings<readonly T>(value: T): Result<T> {
   // ...
}

as far as how to make an interface immutable:

readonly interface Point {
   readonly x: number;
   readonly y: number;
}

so the problem being solve here is to make sure that the caller won't mutate the argument after it is passed to the function

simple use case: a hash-based data container, which calculates a hash of a given value, and will store it at that hash, and it all will work until the value is mutated outside and tha stored hash is no longer valid, so the container doesn't really work anymore

another use case: a cache or object pool or any other situation when there are many parties involved in taking hold of the same object, which must be guaranteed from being mutated by one party to prevent spooky action at a distance for all other parties

Nell’issue non sono indicati alcun file sorgente, test o punto di ingresso. Inizia esaminando come TypeScript rappresenta i vincoli generici e i tipi readonly; il lavoro è completato quando la garanzia proposta sugli argomenti immutabili ha una semantica concordata, una copertura dell’implementazione e test per i casi indicati di hashing, caching e condivisione degli oggetti.