42 lines
1.3 KiB
TypeScript
42 lines
1.3 KiB
TypeScript
// @strict: true
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function f1<T extends string | number, U extends string | number>(x: T & U) {
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// Combined constraint of 'T & U' is 'string | number'
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let y: string | number = x;
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}
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function f2<T extends string | number | undefined, U extends string | null | undefined>(x: T & U) {
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let y1: string | number = x; // Error
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let y2: string | null = x; // Error
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let y3: string | undefined = x;
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let y4: number | null = x; // Error
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let y5: number | undefined = x; // Error
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let y6: null | undefined = x; // Error
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}
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type T1 = (string | number | undefined) & (string | null | undefined); // string | undefined
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function f3<T extends string | number | undefined>(x: T & (number | object | undefined)) {
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const y: number | undefined = x;
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}
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function f4<T extends string | number>(x: T & (number | object)) {
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const y: number = x;
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}
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function f5<T, U extends keyof T>(x: keyof T & U) {
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let y: keyof any = x;
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}
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// Repro from #23648
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type Example<T, U> = { [K in keyof T]: K extends keyof U ? UnexpectedError<K> : NoErrorHere<K> }
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type UnexpectedError<T extends PropertyKey> = T
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type NoErrorHere<T extends PropertyKey> = T
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// Repro from #30331
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type a<T> = T extends Array<infer U> ? U : never;
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type b<T> = { [K in a<T> & keyof T ]: 42 };
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