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=== tests/cases/compiler/mappedTypeUnionConstraintInferences.ts ===
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
>Omit : Omit<T, K>
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
>PartialProperties : PartialProperties<T, K>
export function doSomething_Actual<T extends {
>doSomething_Actual : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
prop: string;
>prop : string
}>(a: T) {
>a : T
const x: { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; } = null as any;
>x : { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
>null as any : any
>null : null
return x;
>x : { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
}
export declare function doSomething_Expected<T extends {
>doSomething_Expected : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
prop: string;
>prop : string
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
>a : T
export let a = doSomething_Actual({ prop: "test" });
>a : { prop?: string; }
>doSomething_Actual({ prop: "test" }) : { prop?: string; }
>doSomething_Actual : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
>{ prop: "test" } : { prop: string; }
>prop : string
>"test" : "test"
a = {} // should be fine, equivalent to below
>a = {} : {}
>a : { prop?: string; }
>{} : {}
export let b = doSomething_Expected({ prop: "test" });
>b : { prop?: string; }
>doSomething_Expected({ prop: "test" }) : { prop?: string; }
>doSomething_Expected : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
>{ prop: "test" } : { prop: string; }
>prop : string
>"test" : "test"
b = {} // fine
>b = {} : {}
>b : { prop?: string; }
>{} : {}
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