Evaluate user-defined generic type aliases on hover

Let's say we have a class like this:

class A
{
    readonly x = 99;
    s: string;

    constructor(initialiser: { [K in Exclude<keyof A, 'x'>]: A[K] })
    {
        for (const k in initialiser) this[k] = initialiser[k];
    }
}

Now, when I hover over the ctor param, VS Code shows me the type: { s: string; }.

Since I need such an initialiser for several classes, I have written a generic type alias:

type InitialiserExclude<C, Keys extends keyof C> = { [K in Exclude<keyof C, Keys>]: C[K] };

When I replace the initialiser type by InitialiserExclude<A, 'x'>, that's exactly what I see when hovering over the ctor param.

It would be very nice if VS Code evaluated such user-defined type aliases as it does with e. g. the built-in Exclude<T, U> and showed the resulting object type.

This is not only a matter of usability of the class. To create more complex initialiser types, it can be necessary to define multiple generic type aliases and use one within another, and the only way I know to check if such an initialiser works as expected is to declare a variable with that type and hover over it.

Usa los ejemplos de TypeScript del issue como reproducción: compara la salida al pasar el cursor sobre el tipo mapped inline, el Exclude integrado y el alias InitialiserExclude definido por el usuario. Empieza rastreando el comportamiento del hover del servicio de lenguaje para estos tipos. Se considera terminado cuando, al pasar el cursor sobre el parámetro del constructor, el alias definido por el usuario se expande al tipo de objeto resultante.