Generic derived value type

Hey guys.
I can not see if I'm doing anything wrong here. I am expecting to be able to get exact type from generic type ...
Is this just limitation of typescript or i am doing anything whrong here?

TypeScript Version: 3.1.3

Search Terms:
Generic derived value type

Code

export type filterTypeName = 'price' | 'price_range';
export type priceFilterValue = {
  from: number;
  to: number;
};
export type priceRangeFilterValue = {
  fromRange: number;
  toRange: number;
};

export type filterValueType<T extends filterTypeName> =  
    T extends 'price' ? priceFilterValue
    : T extends 'price_range' ? priceRangeFilterValue : never;


type productFilterParameters<T extends filterTypeName> = {
  filter: T;
    value: filterValueType<T>;
};

function addProductFilter<T extends filterTypeName>(params: productFilterParameters<T>) { 
    switch (params.filter) { 
        case 'price':
            const priceFrom = params.value.from; //Property 'from' does not exist on type 'filterValueType<T>'    
            break;
        default:
            break;            
    }
}

// parameter value is derivered based on filter type... not working id function definition
addProductFilter({ filter: 'price', value: { from: 1, to: 2 } });

//expected behavior something like this

type productFilterParametersCorrect = {
    filter: 'price';
    value: priceFilterValue;
} | {
    filter: 'price_range';
    value: priceRangeFilterValue;
}

function addProductFilterCorrect(params: productFilterParametersCorrect) { 
    switch (params.filter) { 
        case 'price':            
            const priceFrom = params.value.from; // correct
            break;
        case 'price_range':
            const priceRangeFrom = params.value.fromRange; // correct
        default:
            break;            
    }
}

Expected behavior:
Code

const value: priceFilterValue

Actual behavior:
Code

const value: filterValueType<T>

Playground Link:
Playground

Related Issues:

Commencez par le Playground lié et par l’exemple générique addProductFilter utilisant TypeScript 3.1.3, puis comparez le comportement du paramètre générique avec l’union définie explicitement. C’est terminé lorsque le switch sur params.filter fournit les propriétés de valeur correspondantes sans l’erreur signalée ; le payload ne mentionne aucun fichier ni test du dépôt.