With regards to type arguments for a function, is ...

# announcements

[Joost de Vries]

With regards to type arguments for a function, is there a way not to have to specify all three when calling this function?
https://pl.kotl.in/kMoCgjgsg
That would be a very handy utility function to have for our codebase but having to specify superfluous type arguments undoes the value.

[spand]

cant you just do (c as? Foo)?.fooString ?

[spand]

Shorter too

[spand]

But to answer your question I dont think so

[Joost de Vries]

I didn't know about the conditional cast. Tx!

[Joost de Vries]

I thought it should be possible: the Kotlin compiler does know the latter two types...

[Joost de Vries]

The conditional cast doesn't check at compile time whether it's a subclass unfortunately. So that makes it a rather blunt instrument.

[spand]

What do you mean doesnt check ? I get a warning in this:

val foo = ""
(foo as? Int)?.toShort()

[Joost de Vries]

Aha, I didn't see that warning. Somehow I expected a compiler error.

[ribesg]

Well there’s no compiler error as the code is correct

[ribesg]

The cast never succeeding isn’t an error, just probably not something you wanted to do, that’s a warning

[spand]

Well, it would be quite opinionated to error on it but it would be reasonable in my opinion. ie. java errors on unreacheable code (Kotlin doesnt so is similar to this case)

[ribesg]

You can set that warning as being an error in your IDE if you want.

[Joost de Vries]

In our codebase we'd prefer to treat this as an error since it means that the reasoning of the code is wrong.

[Joost de Vries]

Unfortunately the IDE is not our quality gatekeeper, CI is...

[ribesg]

https://www.jetbrains.com/help/idea/command-line-code-inspector.html

[Joost de Vries]

Interesting, I hadn't found that. I wonder how hard it would be to trigger that from gradle.

[ribesg]

Well https://github.com/JetBrains/inspection-plugin

[Joost de Vries]

Ha! Ask and thou shallt receive