Enhance members of literal type like const array type (e.g. string literal types should have literal length property)

The const array type, its principle members are also be the constant. When define a const array [number, string, boolean], its length type be 3. Also, when access to special index, the type also points the exact const type.

function const_array(): void
{
    let elements: [number, string, false] = [3, "something", false];
    let length: 3 = elements.length;

    let first: number = elements[0];
    let second: string = elements[1];
    let third: false = elements[2];
}

However, the literal type is not like the const array. When define a literal type "something", its length be not 9 but number. Also, when access to a special index, the type is not a special literal type but a string type.

function literal(): void
{
    let word: "something" = "something" as const;
    let length: number = something.length; // not 9 but number

    let first: string = word[0]; // not "s" but string
    let second: string = word[1]; // not "o" but string
    let third: string = word[2]; // not "m" but string
}

What about enhancing the literal type to be like the const array type?

Non vengono indicati file o test. Inizia individuando i percorsi di controllo dei tipi per l'accesso alle proprietà tramite stringhe letterali e per l'accesso indicizzato, quindi confronta il loro comportamento con la gestione delle tuple. Il lavoro è completato quando le stringhe letterali espongono una lunghezza letterale e tipi di carattere letterali agli indici noti, con test appropriati di controllo dei tipi.