infer在遇到交集时总是取最后一个重载（这实际上只是描述重载的另一种方式），不管你如何定义它。最后一个重载是交集中的最后一个成员或代码中的最后一个定义：

type One = (() => 1) & (() => 2);
type Two = { (): 1; (): 2; };

type MutuallyAssignable = One extends Two ? Two extends One ? true : false : false;
//   ^? true

function three(): 1;
function three(): 2;
function three() { return 42 }

type Three = typeof three;

class C {
    four(): 1;
    four(): 2;
    four() { return 42 }
}

type Four = C["four"];

type T<F> = F extends (...args: any[]) => infer R ? R : unknown;

type T01 = T<One>;
//   ^? 2
type T02 = T<Two>;
//   ^? 2
type T03 = T<Three>;
//   ^? 2
type T04 = T<Four>;
//   ^? 2

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