Hi All, consider the following function signature:...

# language-evolution

[uli]

Hi All,
consider the following function signature:

inline fun <reified T: Fragment> replaceFragment(
        name: String = T::class.java.name
    )

Why do I need inline refied in the signature?
I do understand that T.class.java can not work on an erased type but, If I understand correctly, kotlin would insert the default parameters at call site where the type information is readily available.

If I am not mistaken in my assumptions, I propose to lift the restriction on generic types for when they are used in default parameter definitions.

[ephemient]

default parameters are resolved in the called function, not in the caller

[ilya.gorbunov]

Without reified the function could be called with non-reified T.

[uli]

Thanks @ephemient, checked decompiled bytecode and found replaceFragment$default
Interesting. Learned something new today 🙂

Somehow I was sure the compiler would insert the missing parameters at call site with all the consequences regarding changing default parameters in a library.

Good to see that kotlin is again a bit smarter then me 🙂

[ephemient]

well it does make some things harder, such as https://youtrack.jetbrains.com/issue/KT-18695, but overall I think it's a good choice

[elizarov]

There are occasional cases where you want the default parameters on the call-site. We call those "inline default parameters". You can vote for this feature and/or add your use-cases (if any) here: KT-50113 Inline default parameters for functions