Incorrect Apparent Type of a Union of Constructors

[LukeAbby]

🔎 Search Terms

union of constructors, InstanceType, narrowing

🕗 Version & Regression Information

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

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=4.9.5#code/CYUwxgNghgTiAEkoGdnwKIA8oFsAOEIAwtKvAN4CwAUPHfHjAPZ4Bc8AdgK44BGIMANw0AvjRoAXAJ54EAFSgBrEMiy4CIADxz4ITBJAdgaNfkIkUyAHzwAvPDnDqkmfJUTtu-YePxpspgAzDGwzYlI0AB94AAoOEAB3WIBKOxsmXgArcAlkm3sdPQMjNH8QIJD1cwiaengAfgclFVMNTQBJDmQJKA4wEDlXbSsrWvoAenG66bqAPQdXeAByTu7e-sHZYaX4YCYVTiYJeGQoCQBLZECpPwALBDAmLokYKHOOY6XW6sslgDoxnRJjMQXVNggllwOIoOEwEhwdpdDsdLOcAOYcKC8Qh+Jh+RZfUIaCyof6A+DA0FUhayZYZbJgY7Rb7hX7wJGwlGodGY7EICR4srLFkk5Bk2gTKbU6kABWYshg0mWjBYiLQOEuyHeaPZHHxtKW5BEO14XGOcAAjlxznBgLr9RCRRFxXV2PEAG4CQRAA

💻 Code

declare class ExampleClass {
    prop: number;
}

type TakesExample<T extends ExampleClass> = T;

type Test<T extends typeof ExampleClass | (new () => object)> = T extends typeof ExampleClass
    ? TakesExample<InstanceType<T>>
    //             ^ Type 'InstanceType<T>' does not satisfy the constraint 'ExampleClass'.
    //                 Type 'unknown' is not assignable to type 'ExampleClass'.
    //                   Type 'object | ExampleClass' is not assignable to type 'ExampleClass'.
    //                     Property 'prop' is missing in type '{}' but required in type 'ExampleClass'.
    : never;

🙁 Actual behavior

This errors because it appears to lose the context that T is typeof ExampleClass when ran through InstanceType. I find this especially odd because if you make a TakesExampleClass<T> it'll succeed.

🙂 Expected behavior

No error.

Additional information about the issue

No response