Generic class-scoped arrow functions lack access to class-level type reflections

[Oblarg]

When defining generic class functions whose lower bounds depend on class-level generics, the lower bound types will resolve/expand based on the value of those generics. For example, consider this (very lengthy) string literal union:

However, if a similar function is defined with an arrow function, the lower bound does not expand and is instead broadened to just string:

The type constraints are identical between these two functions; they differ only in that the former is a class method and the latter is an arrow function.

It would be really nice if the rendering were consistent here.

[Gerrit0]

Please provide a code snippet that can be used to reproduce this

[Oblarg]

export type BaseUnionMember = {
    type: string;
}

export type Union =
    {
        type: "one"
    } |
    {
        type: "two"
    }

export class GenericClass<U extends BaseUnionMember> {
    public arrowFunction = <MemberType extends U['type']>(member: Extract<U, { type: MemberType}>) => {

    }

    public classFunction<MemberType extends U['type']>(member: Extract<U, { type: MemberType}>) {

    }
}

export class ResolvedSubclass extends GenericClass<Union> {

}