56 lines
1.4 KiB
TypeScript
56 lines
1.4 KiB
TypeScript
// regression test from https://github.com/Microsoft/TypeScript/issues/29692
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interface DeepObject {
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[k1: string]: {
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[k2: string]: any;
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};
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}
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type keys2broken<
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O extends DeepObject,
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K1 extends keyof O
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> = O[K1] extends object ? Extract<keyof O[K1], string> : never;
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type keys2working<
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O extends DeepObject,
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K1 extends keyof O
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> = O[K1] extends object ? keyof O[K1] : never;
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type keys2workaround<O extends DeepObject, K1 extends keyof O> = Extract<
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O[K1] extends object ? keyof O[K1] : never,
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string
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>;
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interface Foo extends DeepObject {
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a: {
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"1": 123;
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"2": string;
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"3": boolean;
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};
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}
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class Bar<O extends DeepObject> {
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broken<
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K1 extends keyof O,
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K2 extends keys2broken<O, K1>,
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V extends O[K1][K2]
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>(k1: K1, k2: K2, value: V) {}
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working<
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K1 extends keyof O,
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K2 extends keys2working<O, K1>,
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V extends O[K1][K2]
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>(k1: K1, k2: K2, value: V) {}
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workaround<
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K1 extends keyof O,
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K2 extends keys2workaround<O, K1>,
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V extends O[K1][K2]
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>(k1: K1, k2: K2, value: V) {}
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}
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const bar = new Bar<Foo>();
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// all 3 of the below should error on passing `true` for `"1"`
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bar.broken("a", "1", true); // was broken in the past - with 2nd argument incorrectly of type "1" | "2" | "3".
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bar.working("a", "1", true); // ok - true is not allowed
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bar.workaround("a", "1", true); // ok - true is not allowed
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