Constraint generics param does not satisfy type infer expression.

[thynson]

Bug Report

🔎 Search Terms

Constraint generics param does not satisfy type infer expression.

🕗 Version & Regression Information

4.7.4 and 4.8.2, earlier versions may behave the same.

⏯ Playground Link

Playground link with relevant code

💻 Code

type Types<T> = (T extends {} ? 'object' : never ) | 'primitive'

function accept<T>(a: Types<T>) {
}

function b<T extends {}>(a: T) {
    accept<T>('primitive'); // Okay
    accept<T>('object'); // Error: TS2345
    accept<T & object>('object'); // Okay, but T already extends from {}, such workaround shall not be required
}

🙁 Actual behavior

tsc accepts the above code

🙂 Expected behavior

the above code is rejected

[whzx5byb]

Duplicate of #31096

[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.