Suspected breaking change with pushing and assigning a 'derived' value into a 'base' array

🔎 Search Terms

inline assignment array derived base push 'Object literal may only specific known properties'

🕗 Version & Regression Information

• This changed between versions 4.9.5 and 5.0.4

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.0.4#code/JYOwLgpgTgZghgYwgAgEJwM4oN4FgBQyywAJgFzIgCuAtgEbQDcBAvgQaJLIigCLTAAbhBLIIAD0ggSGNJhwEiIODQgUMYKKADmzfG3wEEAexAbikGhgrosAbQC6yALzJHeggBsIYCxBoAjBT8WsIket6+wJYATMECYR740f4BLsjYxOTIAQA0lCpqyADkYAAWwLKVyMYA1shQENpwUCTeGBjFyCx6KVYAdAAOVBhlABR9AQCUSX0YQyPjE7HpmaQUMfnKqhSlFVWyAHIA8gAqNfWgyACs-QAM-QAs+XRUUbJ1xCDIj-0AnP1rl0WFMZkA

💻 Code

interface Base {
  id: number;
}

interface Derived extends Base {
  name: string;
}

const items: Base[] = [];

let item1: Derived;
let item2: Derived;

item1 = { id: 1, name: 'this is ok regardless' };
items.push(item1);

items.push((item2 = { id: 2, name: 'this is NOT ok in 5.0.4, but is ok in 4.9.5' }));

🙁 Actual behavior

'Object literal may only specific known properties' error

🙂 Expected behavior

The code should not produce an error

Additional information about the issue

It is possible that this is a change to the order in which types are inferred, but I have been unable to find any details in the documentation/changelog.

Start with the linked TypeScript Playground reproduction and compare it under 4.9.5 and 5.0.4. Trace type inference and checking for the assignment expression passed to items.push; done means the sample compiles without the excess-property error while preserving the Base[] and Derived relationship.