9 lines
287 B
TypeScript
9 lines
287 B
TypeScript
function f<T, U>(y: T, f: (x: T) => U, x: T): [T, U] { return [y, f(x)]; }
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interface A { a: A; }
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interface B extends A { b; }
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var a: A, b: B;
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var d = f(b, x => x.a, a); // type [A, A]
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var d2 = f(b, x => x.a, null); // type [B, A]
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var d3 = f(b, x => x.b, null); // type [B, any]
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