Closed
Description
TypeScript Version: 3.2.1
Search Terms:
keyof, Record, Partial, ...
But actually, I don't know how to exactly express this problem in the search box...
Code
// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
interface ITest {
a: string;
}
type PartialRecord<K extends keyof any, T> = {
[k in K]?: T;
};
class SlotTest<ES> {
private _slots1: Partial<Record<keyof ES, ITest>> = {};
private _slots2: Record<keyof ES, ITest> = {} as any;
private _slots3: PartialRecord<keyof ES, ITest> = {};
public doTest1<K extends keyof ES>(name: K): void {
/**
* It works well in v2.9.x, but fails in v3.2.1.
* [ts] Type '{ a: string; }' is not assignable to type 'Record<keyof ES, ITest>[K]'. [2322]
*/
this._slots1[name] = {"a": "ggg"};
}
public doTest2<K extends keyof ES>(name: K): void {
/**
* This works fine.
*/
this._slots2[name] = {"a": "ggg"};
}
public doTest3<K extends keyof ES>(name: K): void {
/**
* This works fine.
*/
this._slots3[name] = {"a": "ggg"};
}
}Expected behavior:
When I used v2.9.2, the code works well.
Actual behavior:
But, when I upgrade to v3.2.1, it fails with compilation error message like this:
Type '{ "a": string; }' is not assignable to type 'Record<keyof ES, ITest>[K]'.
Playground Link:
Related Issues:
#18538 maybe