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//// [extractInferenceImprovement.ts]
// repro mostly from https://github.com/Microsoft/TypeScript/issues/25065
function getProperty2<T, K extends keyof T>(obj: T, key: Extract<K, string>): T[K] {
return obj[key];
}
function getProperty3<T, K extends Extract<keyof T, string>>(obj: T, key: K): T[K] {
return obj[key];
}
const s = Symbol();
interface StrNum {
first: string;
second: number;
[s]: string;
}
const obj: StrNum = {} as any;
let prop: string;
// should work
prop = getProperty2(obj, 'first');
prop = getProperty3(obj, 'first');
// Should fail
prop = getProperty2(obj, s);
prop = getProperty3(obj, s);
//// [extractInferenceImprovement.js]
// repro mostly from https://github.com/Microsoft/TypeScript/issues/25065
function getProperty2(obj, key) {
return obj[key];
}
function getProperty3(obj, key) {
return obj[key];
}
const s = Symbol();
const obj = {};
let prop;
// should work
prop = getProperty2(obj, 'first');
prop = getProperty3(obj, 'first');
// Should fail
prop = getProperty2(obj, s);
prop = getProperty3(obj, s);
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