Change return type of `Object` call signature to `unknown` (currently `any`)

🔎 Search Terms

ObjectConstructor, Object, assignable, function

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about 5.3.3

⏯ Playground Link

https://www.typescriptlang.org/play?#code/CYUwxgNghgTiAEAzArgOzAFwJYHtVJxwAowAjALniIEp4BeAPngGcMYtUBzaygNxyzAA3ACgRiQjSEB6afECg5PACiADwAO4DCGDw4zZBAyUQMGDhjjJNekwBEt6jLmLVGzNt0h9hyqhzwTMwsJYmtGeFQDCEdZBWV1TQ89AyMA03NLYgBvAF9qWJcE9x1knzSgzKIAZTYObic410SSrxTff0CMkKIAOWQAW1ITGOd4ty0W71TOi0qAeVIAK00R+EAZcjHmzynjdIsgA

💻 Code

declare function foo(cb: () => string): void;

foo();// ✅ Expected result: error
foo(() => "");// ✅ Expected result: no error
foo(() => null);// ✅ Expected result: error
foo({})// ✅ Expected result: error
foo(String);// ✅ Expected result: no error
foo(Number);// ✅ Expected result: error

foo(Object);// ❌ Expected result: error

🙁 Actual behavior

Object (ObjectContructor) is assignable to any function, because it has a callable signature with return type of any.

This lets the developers to use Object where only a properly typed function would be allowed, which can lead to unexpected runtime errors.

I know this is a pretty edge case, but in my opinion it's worth looking into.

🙂 Expected behavior

Object is not assignable to functions with different return type

Additional information about the issue

No response

Inizia con l’esempio collegato di TypeScript Playground e con la firma di chiamata di ObjectConstructor descritta nell’issue. Verifica come cambia l’assegnabilità modificando il tipo restituito da any a unknown, quindi verifica che Object venga rifiutato per la callback mostrata che restituisce una stringa, mentre gli altri esempi mantengono i risultati attesi.