Object spreading produces wrong type with non-literal keys

🔎 Search Terms

object spread, object rest, object spreading

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about object spreading

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.2.2#code/CYUwxgNghgTiAEYD2A7AzgF0QLngb3gG0BrEAT10xgEsUBzAXVxQFcBbAIxBngF8BYAFDJ0WKLgIlylDDXpN4VWnT7wAvPiEBIcfADkegDTaAdGbBDeQA

💻 Code

declare const c: { [key: string]: number }
const a: { [key: string]: string } = {
	a: '',
	...c
}

🙁 Actual behavior

It allows numbers to be in the object, when they shouldn't be allowed.

🙂 Expected behavior

It shouldn't allow numbers.

Additional information about the issue

Because c has non-literal keys, in this case string, which could be any string, it doesn't care what's in it.

Inizia con la riproduzione collegata in TypeScript Playground e verifica che l'assegnazione segnalata venga accettata. Traccia come viene tipizzato object spread con una chiave di indice string non letterale, quindi conferma che il fix rifiuti lo spread con valore numerico in questo esempio e aggiungi o aggiorna la coverage per questo comportamento.