@robstoll any reason you need to specify the type?

Unfortunately yes, I saw that it works if I do not have to

You don't. This works for me:

fun main(args: Array<String>) {
    1 doStuff 1.2
}

infix fun <T> Int.doStuff(t: T) { println(t) }

I am using it in a generic function, something like

fun <T> foo(a: T){ 1 test<T> a }

can you put that into a code block in slack. its hard to read like that

It is already in a code block, I'll put the parameter on a new line:

infix inline fun <reified TSub : Any> IAssertionPlant<Any>.isA( 
    noinline assertionCreator: IAssertionPlant<TSub>.() -> Unit
)

shouldn’t it be IAssertionPlant<Tsub>

in case you mean

IAssertionPlant<Any>

, then nope

isA

is basically a down-cast assertion which allows you to tell that

val a: Any = 1; assert(a).isA<Int>{}

for instance