Error from `exactOptionalPropertyTypes` not reported when using object spread with a ternary and optional property acces

[aswinsvijay]

🔎 Search Terms

exactOptionalPropertyTypes
object spread
ternary

🕗 Version & Regression Information

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

⏯ Playground Link

https://www.typescriptlang.org/play/?exactOptionalPropertyTypes=true&ts=5.9.3&ssl=5&ssc=32&pln=1&pc=1#code/C4TwDgpgBAYg9nKBeKBvAUFKYCGAnCAO2AEkATAfgC4oBnYPAS0IHN0BfddMiAYwBt80XnEL0oBAI4BXCPQBCcMiBrw4Abi78IwKMHwsdqhJvQB6M3QAWcAO60oEAB6RewCGUd48cPFDKyeogAok44bgDyYMCMojj8AAo+kHigACrgcuj6eIa6KKjYQsTkNFKyCkogAHS4BCWe7KYWUAC2jLS0zCxePn62VkRQ0l2sdGAEOJ44hJ7ueIT4INkGOshoUNVbABQMgRQbdUSkZGUQMnLAisq1xSdQ7FA0qOwAlA-qUC3yAKoA4lwRGJdIUjg0HutypdriBNDk8utCltqrs8PtDndSkV6vdHs83h8sF9LL8AeZLBBvL4oDgwJB8A4RN4+MB+CAoIwAGZQABu8UCHSghDguhw2GSlNANN4vDktA8UE5PlaNMIUDgACMAFYs9BA8Rgk4AJnWAHJTTSHPQmGMAD7DWYQTnMDxw1b5DbI1Ho0GY07Y47kE14tAEproIA

💻 Code

type Foo = {
  parentId?: string
}

declare const requestBody: Foo;

let target: Foo;

// shows expected error due to ExactOptionalPropertyTypes
target = { parentId: requestBody.parentId };

// missing error when using spread and ternary
target = { ...(true ? { parentId: requestBody.parentId } : {}) }; // BUG

const { parentId } = requestBody;
target = { ...(true ? { parentId: parentId } : {}) };   // BUG

// error appears correctly if value is not a property accessed from an object
const parentId2 = '' as string | undefined;
target = { ...(true ? { parentId: parentId2 } : {}) };

🙁 Actual behavior

The expected error is silenced only in the specific case that combines object spread, ternary, and accessing an optional property from an object, although the types are always recognized correctly with | undefined.

🙂 Expected behavior

All scenarios demonstrated in the code snippet are expected to show the same error.

Additional information about the issue

No response

[RyanCavanaugh]

Confirmed repro in tsgo