TypeScript/tests/baselines/reference/mappedTypeWithAny.types
Anders Hejlsberg b0ab2a54bb
Fix mapped type instantiation circularity (#46586)
* Don't obtain constraint if doing so would cause circularity

* Add regression test

* Address CR feedback
2021-10-29 14:01:27 -07:00

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=== tests/cases/conformance/types/mapped/mappedTypeWithAny.ts ===
type Item = { value: string };
>Item : Item
>value : string
type ItemMap<T> = { [P in keyof T]: Item };
>ItemMap : ItemMap<T>
declare let x0: keyof any;
>x0 : string | number | symbol
declare let x1: { [P in any]: Item };
>x1 : { [x: string]: Item; [x: number]: Item; [x: symbol]: Item; }
declare let x2: { [P in string]: Item };
>x2 : { [x: string]: Item; }
declare let x3: { [P in keyof any]: Item };
>x3 : { [x: string]: Item; }
declare let x4: ItemMap<any>;
>x4 : ItemMap<any>
// Repro from #19152
type Data = {
>Data : Data
value: string;
>value : string
}
type StrictDataMap<T> = {
>StrictDataMap : StrictDataMap<T>
[P in keyof T]: Data
}
declare let z: StrictDataMap<any>;
>z : StrictDataMap<any>
for (let id in z) {
>id : string
>z : StrictDataMap<any>
let data = z[id];
>data : Data
>z[id] : Data
>z : StrictDataMap<any>
>id : string
let x = data.notAValue; // Error
>x : any
>data.notAValue : any
>data : Data
>notAValue : any
}
// Issue #46169.
// We want mapped types whose constraint is `keyof T` to
// map over `any` differently, depending on whether `T`
// is constrained to array and tuple types.
type Arrayish<T extends unknown[]> = { [K in keyof T]: T[K] };
>Arrayish : Arrayish<T>
type Objectish<T extends unknown> = { [K in keyof T]: T[K] };
>Objectish : Objectish<T>
// When a mapped type whose constraint is `keyof T` is instantiated,
// `T` may be instantiated with a `U` which is constrained to
// array and tuple types. *Ideally*, when `U` is later instantiated with `any`,
// the result should also be some sort of array; however, at the moment we don't seem
// to have an easy way to preserve that information. More than just that, it would be
// inconsistent for two instantiations of `Objectish<any>` to produce different outputs
// depending on the usage-site. As a result, `IndirectArrayish` does not act like `Arrayish`.
type IndirectArrayish<U extends unknown[]> = Objectish<U>;
>IndirectArrayish : Objectish<U>
function bar(arrayish: Arrayish<any>, objectish: Objectish<any>, indirectArrayish: IndirectArrayish<any>) {
>bar : (arrayish: Arrayish<any>, objectish: Objectish<any>, indirectArrayish: IndirectArrayish<any>) => void
>arrayish : any[]
>objectish : Objectish<any>
>indirectArrayish : Objectish<any>
let arr: any[];
>arr : any[]
arr = arrayish;
>arr = arrayish : any[]
>arr : any[]
>arrayish : any[]
arr = objectish;
>arr = objectish : Objectish<any>
>arr : any[]
>objectish : Objectish<any>
arr = indirectArrayish;
>arr = indirectArrayish : Objectish<any>
>arr : any[]
>indirectArrayish : Objectish<any>
}
declare function stringifyArray<T extends readonly any[]>(arr: T): { -readonly [K in keyof T]: string };
>stringifyArray : <T extends readonly any[]>(arr: T) => { -readonly [K in keyof T]: string; }
>arr : T
let abc: any[] = stringifyArray(void 0 as any);
>abc : any[]
>stringifyArray(void 0 as any) : string[]
>stringifyArray : <T extends readonly any[]>(arr: T) => { -readonly [K in keyof T]: string; }
>void 0 as any : any
>void 0 : undefined
>0 : 0
declare function stringifyPair<T extends readonly [any, any]>(arr: T): { -readonly [K in keyof T]: string };
>stringifyPair : <T extends readonly [any, any]>(arr: T) => { -readonly [K in keyof T]: string; }
>arr : T
let def: [any, any] = stringifyPair(void 0 as any);
>def : [any, any]
>stringifyPair(void 0 as any) : string[]
>stringifyPair : <T extends readonly [any, any]>(arr: T) => { -readonly [K in keyof T]: string; }
>void 0 as any : any
>void 0 : undefined
>0 : 0
// Repro from #46582
type Evolvable<E extends Evolver> = {
>Evolvable : Evolvable<E>
[P in keyof E]: never;
};
type Evolver<T extends Evolvable<any> = any> = {
>Evolver : Evolver<T>
[key in keyof Partial<T>]: never;
};