Types not matching when use destructuring assignment, but the hint error is ignored

[hxse]

Bug Report

🔎 Search Terms

Types not matching destructuring assignment hint error ignored

🕗 Version & Regression Information

ts version: 4.6.4

⏯ Playground Link

https://www.typescriptlang.org/play?#code/C4TwDgpgBAhgKuaBeKBvWAuKA7ArgWwCMIAnKAXwFgAoAYwHtsBnYTWBSKFdGLARgBMAZgA0UQlgAsAVgBsFGg2asJ7RFzRtBoqADp96VTPnkF1IA

💻 Code

type aType = { a: number }
const a: aType = { a: 123, b: 456 } // ✅ hint error 
const b: aType = { a: 123, ...{ b: 456 } }// ❌ not hint error, why?

🙁 Actual behavior

const a hint the error
const b not hint the error

🙂 Expected behavior

const a hint the error
const b hint the error too, beacuse aType don't match "{ b: 456 }"

[Josh-Cena]

See #39998

There's no type-safety loophole here, to say the least... Excess property checks is more of a linting feature.

[hxse]

let me add tow lines
https://www.typescriptlang.org/play?ssl=7&ssc=1&pln=1&pc=1#code/C4TwDgpgBAhgKuaBeKBvWAuKA7ArgWwCMIAnKAXwFgAoAYwHtsBnYTWBSKFdGLARgBMAZgA0UQlgAsAVgBsFGg2asJ7RFzRtBoqADp96VTPnkF1RYxZRaWdDZwFiZU92tYA7AA4AnGaVWAEyx4dVdeKG0xfV1aMyA

type aType = { a: number }
const a: aType = { a: 123, b: 456 } // ✅ hint error 
const b: aType = { a: 123, ...{ b: 456 } }// ❌ not hint error, why?

const c: { c: number } = { c: 789 }
const d: aType = { a: 123, ...c } // ❌ not hint error, why?

The type of const c is certain, but const d still does not hint the error, Isn't this strange?

[Josh-Cena]

Excess property checks only kick in when the RHS is an object literal, because otherwise there's a non-negligible possibility that you are reusing an object value from elsewhere.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.