fd1e22bbf1
* Instantiate generic conditional infer source types in the context of the target conditional * Add test case from #26627
29 lines
836 B
TypeScript
29 lines
836 B
TypeScript
function f<X>(arg: X) {
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type Cond1 = X extends [infer A] ? A : never;
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type Cond2 = X extends [infer A] ? A : never;
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let x: Cond1 = null as any;
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let y: Cond2 = null as any;
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x = y; // is err, should be ok
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y = x; // is err, should be ok
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}
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// repro from https://github.com/microsoft/TypeScript/issues/26627
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export type Constructor<T> = new (...args: any[]) => T
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export type MappedResult<T> =
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T extends Boolean ? boolean :
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T extends Number ? number :
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T extends String ? string :
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T
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interface X {
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decode<C extends Constructor<any>>(ctor: C): MappedResult<C extends Constructor<infer T> ? T : never>
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}
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class Y implements X {
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decode<C extends Constructor<any>>(ctor: C): MappedResult<C extends Constructor<infer T> ? T : never> {
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throw new Error()
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}
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}
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