嵌套函數中的接口中的泛型

Question

interface Maybe<A> { 
    // this works as expected 
    a: <B>(a: A, b: Maybe<B>) => Maybe<B>; 

//# Maybe#chain :: Maybe a ~> (a -> Maybe b) -> Maybe b 
    // this does not 
    chain: <B>((a: A) => Maybe<B>) => Maybe<B>; 
} 

如何在代碼段中顯示函數期望函數和共享類型變量的「級別」？或者說，TypeScript的類型系統太弱，無法表達它？

Answer 1

哦，我忘了說出一個論點。工作版本（請注意fn）：

chain: <B>(fn: (a: A) => Maybe<B>) => Maybe<B>;