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?

ファイルもテストも指定されていません。まず、文字列リテラルによるプロパティアクセスとインデックスアクセスの型チェック経路を特定し、次にタプルの処理とその挙動を比較してください。文字列リテラルがリテラルな長さと、既知のインデックスにおけるリテラルな文字型を提供し、適切な型チェックテストがある状態を完了とします。