22 lines
672 B
TypeScript
22 lines
672 B
TypeScript
export interface IPromise<T, V> {
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then<U, W>(callback: (x: T) => IPromise<U, W>): IPromise<U, W>;
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}
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interface Promise<T, V> {
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then(callback: (x: T) => Promise<any, any>): Promise<any, any>;
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}
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// Error because type parameter arity doesn't match
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var x: IPromise<string, number>;
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var x: Promise<string, boolean>;
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interface IPromise2<T, V> {
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then<U, W>(callback: (x: T) => IPromise2<U, W>): IPromise2<U, W>;
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}
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interface Promise2<T, V> {
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then<U, W>(callback: (x: T) => Promise2<string, any>): Promise2<any, any>; // Uses string instead of any!
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}
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// Error because string and any don't match
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var y: IPromise2<string, number>;
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var y: Promise2<string, boolean>; |