`infer` not returning expected inner type if another inner type is used in the outer type result

Bug Report

Given a generic outer type with 2 or more inner types, e.g. Foo<A, B>, that does an intersection involving multiple inner types, then infer won't return a specific inner type, it will return the intersection of the desired type plus the entire outer type. This is difficult for me to explain since I don't know the correct terms for everything, so please see the example.

🔎 Search Terms

infer intersection

🕗 Version & Regression Information

• This changed between versions 4.1.5 and 4.2.3

⏯ Playground Link

playground link

💻 Code

type Foo<T extends {}, N extends string> = T & {
  bar: number;
  asdf: N;
};

interface A {
  things: number;
}

type MyFoo = Foo<A, 'asdf'>;

type InnerFromFoo<F> = F extends Foo<infer I, string> ? I : never;

type inner = InnerFromFoo<MyFoo>;

const a: inner = {
  things: 23
};

🙁 Actual behavior

The type inner is the intersection of A and { bar: number, asdf: string }

🙂 Expected behavior

inner should just be A

Inizia con l'esempio collegato di TypeScript Playground e con il tipo condizionale generico InnerFromFoo<F>. Confronta il tipo inner inferito con il risultato A previsto nelle versioni di TypeScript segnalate, quindi verifica che l'esempio inferisca solo il tipo interno anziché un'intersezione con il tipo esterno.