Hi guys, Can anyone point me out for the equivalent of the following Java code in Kotlin?

public <T extends AbstractSomething & InterfaceSomething> ConcreteClass(manager T)

I'm sure (or hoping) that this has been brought up before, but the SEO of the new Kotlin documentation portal is terrible. if you Google for "Kotlin generics", you don't get any official Kotlin docs until the second page of results, and even then those results aren't for "/docs/generics.html", they're for less-related doc pages. anyone aware of an open issue for this?

Hello! How can i force compiler to restrict 'when' expression if not all branches specified and it is not returning or assigning?

hi- in my java project with gradle

6.8.3

, I’m getting nagged on kotlin

1.4.20

vs

1.4.30

— I’m going to downgrade to kotlin-1.4.20 everywhere, is there a better solution?

When coding in Kotlin, do you guys use Git CMD or just use the automatically integrated version-control system in IntelliJ (if you know what I'm talking about)?

I am using

@Deprecated(...)

in my Kotlin library but from a plain Java project, the deprecation is not shown. Is that a known issue or is there anything wrong with my setup? 🤔

Is there any channel for Skiko/Skija that are JetBrains binding for Skia?

viktor: Efficient Vectorized Computations in Kotlin Introducing viktor viktor is an open-source Kotlin library developed by JetBrains Research that aims to make array calculations more efficient. We achieve this by avoiding nested arrays, delegating expensive operations to JNI + SIMD, and providing built-in support for arithmetics on logarithmically-stored numbers. This post is in celebration of the 1.1.0 release. We will discuss […]

I want to make a file parser for some file format for best possible speed, preferably multithreaded. The question is, would writing it in Kotlin/Native instead of C/++ hurt its performance? I suppose Kotlin/Native is fairly slower than C++, but what are your opinions?

Hi, IntelliJ IDEA shows an error when the code references `KClass`:

Class 'kotlin.reflect.KClass' is compiled by a pre-release version of Kotlin and cannot be loaded by this version of the compiler

I'm using Kotlin 1.5.0-M1 in the latest EAP of the IDE with Kotlin plugin targeting 1.5.0 turned on, the project is built using Gradle. `KClass`seems to be referenced correctly by the IDE as coming from the 1.5.0-M1 JAR. Has anybody seen this error before?

Hello, I am trying to return a lambda with a receiver from a

when

statement, but it doesn't seem to work, the receiver does not register. How can I make this work?

Hello, I’m thinking of using Kotlin as a code generation tool for different languages (currently aiming on php and golang). I believe it should be possible, there are already backends for JS and Native. I was wandering if there is any specification/documentation about compiler backends or someone could guide me to better understanding how to start exploring current implementations?

sorry if this is not really kotlin specific, but how can I install the jetbrain sdk JBRSDK8?

Hey! There is a problem in the code generation of interfaces from Common for use in the Swift implementation. Different interfaces have the same method name and signature. The KMM generates names and adds "_" to each subsequent method that has the same signature. Who has already had this problem? Do you have a solution?  interface abcde { fun initialize(reference: ObjectReference) }  interface gfjk { fun initialize(reference: ObjectReference) } code generation interfaces for Swift (app.h) : (swift_name("initialize(reference:)") (swift_name("initialize(reference_:)”)

Does the

!!

operator have any overhead, if the value is never

null

? I'm guessing no, but still...

kotlin's

Duration

has no

.between()

to get a duration between instances. which is fine... but once I include the

java.time.Duration

all the nice kotlin extension functions like

Int.inSeconds

can't be found. Am I just stuck w/ the java ones if I need

between()

?

Hey! I get this error:

2021-03-27 19:53:03.556 [DefaultDispatcher-worker-1] ERROR Application - Unhandled exception caught for CoroutineName(call-handler)
kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation[<http://Dispatchers.IO|Dispatchers.IO>, Continuation at io.ktor.server.engine.BaseApplicationResponse$respondWriteChannelContent$2$1.invokeSuspend(BaseApplicationResponse.kt:166)@4ed1ef02]. Please read KDoc to 'handleFatalException' method and report this incident to maintainers
	at kotlinx.coroutines.DispatchedTask.handleFatalException$kotlinx_coroutines_core(DispatchedTask.kt:144)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:115)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:571)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:750)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:678)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:665)
Caused by: java.lang.NoClassDefFoundError: Could not initialize class kotlinx.coroutines.CompletedExceptionally
	at kotlinx.coroutines.CompletionStateKt.toState(CompletionState.kt:16)
	at kotlinx.coroutines.CompletionStateKt.toState$default(CompletionState.kt:13)
	at kotlinx.coroutines.AbstractCoroutine.resumeWith(AbstractCoroutine.kt:111)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:46)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	... 4 common frames omitted

When i run this function:

val ApplicationCall.accountPrincipal: AccountPrincipal? get() = authentication.principal<AccountPrincipal>()
fun ApplicationCall.user(): Account? = transaction<Account?> {
    Account.find { (Accounts.id) eq accountPrincipal?.id }.firstOrNull()
}

Can anyone explain this behavior to me? [Solved]

Hi! Kotlin documentation says it's better to omit

@param

and

@return

statements from documentation wherever it's possible and mention them explicitly in the description. Do you agree with it and do you really try to omit them or you still use a javadoc-like documentation?

If I set language level 1.8 would lambda compile to invoke dynamic or it is still anonymous class? https://medium.com/@christian.c.carroll/exploring-kotlin-lambda-bytecode-8c2d15afd490

If

extension methods

just get converted to static methods by the compiler, how do they have access to private/internal fields of their parent class? Edit: Answered, they dont.

how do I get the nth element of a sequence ?

mySequence.take(n + 1).last()

doesnt feel right to me

I have an abstract class with a subclass. I want the subclass to define a property with type Class, but its implementation should be a subclass of

Param

. How do I define this?

abstract class Params

abstract class Parent {
    
    abstract val paramsClass: Class<????> // should be a class that extends Params

}

class Subclass : Parent() {
    
    override val paramsClass = MyParams::class.java

}

data class MyParams : Params()

Kotlin 1.5.0-M2 Released – Ensure Smooth Migration to Kotlin 1.5.0 Kotlin 1.5.0-M2 is the last milestone release for Kotlin 1.5.0, which is coming this spring. So this is the last chance to make sure that your projects will successfully work with Kotlin 1.5.0. Install 1.5.0-M2 If you migrate your projects now, you can save yourself time and energy in the future, when Kotlin 1.5.0 comes […]

How do I use jetpack compose to select images from my phone album to add to the user interface?

I was wondering if Kotlin desktop is robust/complete enough to write a full desktop (macOS/Windows) app with? I haven't seen many example projects online and the documentation is non-existent. Should I give it a go? if not, does anyone have any experience with electron with Kotlin Js?

Does this seem like a bug to anyone else? In a Java library the annotations were just switched from jsr305 to jetbrains. There's a getter method defined like this:

/**
     * Get the value of the OutputArguments Property, if it exists.
     *
     * @return the value of the OutputArguments Property, if it exists.
     * @see MethodNodeProperties#OutputArguments
     */
    @Nullable
    public Argument[] getOutputArguments() {
        return getProperty(MethodNodeProperties.OutputArguments).orElse(null);
    }

Now in some Kotlin code that uses this library it is inferring the type to be

Array<Argument?>?

instead of

Array<Argument>?

as it did previously. So now what was once:

override fun getOutputArguments(): Array<Argument> = methodNode.outputArguments ?: emptyArray()

now won't compile unless it's changed to something like this:

override fun getOutputArguments(): Array<Argument> {
    val outputArguments: Array<Argument>? =
        methodNode.outputArguments as Array<Argument>?

    return outputArguments ?: emptyArray()
}

Hello, I am new to Arrow library. Have a question on

arrow.fx.coroutines.Schedule

. Is there a way to get the number of attempt in the Either.catch

Either.catch{
	retry(Schedule.exponential(250.milliseconds)) {
		evalOn(IOPool) {
			//do something
	  		incrementMetricSuccess(attempt)   -------> want to increment metric with the attempt it got successful
		}
	}
}.mapLeft {
	incrementMetricSuccess(attempt)    -------> want to increment metric with the attempt to fail
}

Has anyone started using Apple M1 for android development? how was your experience