Type is not checked when spreading a typed object into another typed object

[vsheyanov]

🔎 Search Terms

"spread object", "spread typed object"

🕗 Version & Regression Information

Tested with TS:

• 5.0.4
• 5.4.5

⏯ Playground Link

https://www.typescriptlang.org/play/?#code/MYewdgzgLgBAbgLhgbxlAptJ0BOBLMAcxgF8YBeFAKBjUyiQHIATRgGipIG4qqB6PjAgALEAFcANsxgAjdDACGYGAFEcOEDiqhIsAqHXpgDFDDzNsUfEVIVqtAHRO4HWuaasO3XgKGiA7hAwACoAyjDo6pra4NAwBjhGJqjuQlYExGSUyDR0WDAs7LmphV5cQA

💻 Code

const v: { test: string } = {
  test: 'd',
};

// should be an Error
const incorrect: { id: string } = {
  ...v,
  id: 'd',
};

// shows TS error
const correct: { id: string } = {
  test: 'd',
  id: 'd',
};

🙁 Actual behavior

It allows to spread anything inside the variable const incorrect. You can even spread ...[], inside incorrect variable and it won't throw an error.

🙂 Expected behavior

If variable v is typed, incorrect case must throw an error.

Additional information about the issue

No response

[MartinJohns]

Another duplicate of #39998. Type checking is working, just excess property checks not.

[vsheyanov]

@MartinJohns thanks for adding a duplicate. I didn't find that one myself.
I wonder if that issue covers also this case:

// should be an Error
const incorrect: { id: string } = {
  ...[],
  id: 'd',
};

[MartinJohns]

#52060 / #9726.

[typescript-bot]

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