Hey everyone, I’ve having some issues with type inference. I have a function similar to the one in SharedPreferences that retrieves a String, and if it doesn’t find it, it’ll return the default parameter that’s nullable

fun getString(key: String?, default: String?): String?

The issue is that I’m trying to make it so that the compiler can tell if the default is null or not, and make the return type null or not. I’ve tried doing this:

fun <T:String?>getString(key: String?, default: T): T

But if the default is value

null

, the inffered type becomes

Nothing?

instead of

String?

Any idea on how to do this properly?

One way could be to have a specific implementation for null and a different one for String:

fun getString(key: String?, default: Nothing?): String?

fun getString(key: String?, default: String): String