internal

"INVISIBLE_REFERENCE"

Cannot assign to ...: the setter is internal in ...

IrGenerationExtension

class Foo {
  object bar {}

  companion object {
    val bar = "companion bar"
  }
}

// I can read the companion bar
println(Foo.bar) // companion bar
// How do I access the object bar?
println(Foo.??)

val evenCount = listOf(1, 2, 3).sumOf { if (it % 2 == 0) 1 else 0 }

sumOf

val evenCount = listOf(1, 2, 3).sumOf { 0 + if (it % 2 == 0) 1 else 0 }

java.lang.IllegalArgumentException: No argument for parameter VALUE_PARAMETER name:_context_receiver_1 index:1

CALL 'public abstract fun display <T1, SubT1> (_context_receiver_0: <root>.Kind<T1 of <root>.Display.display, SubT1 of <root>.Display.display>, _context_receiver_1: <root>.Display<SubT1 of <root>.Display.display, SubT1 of <root>.Display.display>, t1: T1 of <root>.Display.display): kotlin.String declared in <root>.Display' type=kotlin.String origin=null
  <T1>: SubT1 of <root>.ListDisplay.display$lambda-0
  <SubT1>: SubT1 of <root>.ListDisplay.display$lambda-0
  $this: GET_FIELD 'FIELD FIELD_FOR_CAPTURED_VALUE name:$_context_receiver_1 type:<root>.Display<SubT1 of <root>.ListDisplay.display$lambda-0, SubT1 of <root>.ListDisplay.display$lambda-0> visibility:public/*package*/ [final]' type=<root>.Display<SubT1 of <root>.ListDisplay.display$lambda-0, SubT1 of <root>.ListDisplay.display$lambda-0> origin=null
    receiver: GET_VAR '<this>: <root>.ListDisplay.display$lambda-0.<no name provided> declared in <root>.ListDisplay.display$lambda-0.<no name provided>.invoke' type=<root>.ListDisplay.display$lambda-0.<no name provided> origin=null
  _context_receiver_0: TYPE_OP type=SubT1 of <root>.ListDisplay.display$lambda-0 origin=CAST typeOperand=SubT1 of <root>.ListDisplay.display$lambda-0
    GET_VAR 'it: kotlin.Any? declared in <root>.ListDisplay.display$lambda-0.<no name provided>.invoke' type=kotlin.Any? origin=null

"org.jetbrains.kotlin:kotlin-compiler-embeddable:1.5.32"

KotlinCoreEnvironment

configuration.addKotlinSourceRoots(kotlinFiles)
configuration.addJvmClasspathRoots(classpath)

analyzer.analyzeAndReport(files) {
    TopDownAnalyzerFacadeForJVM.analyzeFilesWithJavaIntegration(
        environment.project,
        files,
        NoScopeRecordCliBindingTrace(),
        environment.configuration,
        environment::createPackagePartProvider,
        ::FileBasedDeclarationProviderFactory
    )
}

return analyzer.analysisResult.bindingContext // I use this bindingContext

Foo()
  .bar() // returns Bar object
  .baz() // returns Baz object

Foo

Bar

Baz

BindingContext

BindingTrace

getResolvedCall

getCall

Type

BindingUtils

compileCommonMainKotlinMetadata

PsiElementFinder

Kotlin light classes should not be found by JavaPsiFacade

PsiElementFinder

BindingContext

kotlin-compiler-embeddable

-entry

-Xreport-perf

info: PERF: <redacted_module_name>, 1 files (23 lines)
info: PERF: INIT: Compiler initialized in 1758 ms
info: PERF:         ANALYZE    4307 ms       5.340 loc/s
info: PERF:  IR TRANSLATION     289 ms      79.585 loc/s
info: PERF:     IR LOWERING     494 ms      46.559 loc/s
info: PERF:   IR GENERATION     348 ms      66.092 loc/s
info: PERF:        GENERATE     842 ms      27.316 loc/s
info: PERF: GC time for G1 Young Generation is 47 ms, 2 collections
info: PERF: GC time for G1 Old Generation is 0 ms, 0 collections
info: PERF: JIT time is 22892 ms
info: PERF: Find Java class performed 11 times, total time 234 ms
info: PERF: Type info performed 39 times, total time 2214 ms
info: PERF: Call resolve performed 38 times, total time 2116 ms
info: PERF: Binary class from Kotlin file performed 210 times, total time 226 ms

-Xbackend-threads

jvm-abi-gen

is

as

DeclarationChecker

try {
    throw Error("Oh no!")
} catch {
    console.log("Something bad happened, but don't know what")
}

(e: Exception)

(_: Throwable)

!:

var result = methodThatMightThrowAnError() !: return null

inline fun <reified T> validateSignedToken(token: String) =
    try {
        Json.decodeFromString<T>(jwtVerifier.verify(token).getClaim("payload").asString())
    } catch (e: Exception) {
        null
    }

inline fun <reified T> validateSignedToken(token: String) =
        Json.decodeFromString<T>(jwtVerifier.verify(token).getClaim("payload").asString()) !: null

fun insertTokenTest() {
   assertNoException {
      val person = fetchToken() !: "12345678" //This might cause an exception, but when it is not available we just don't mind an use an default value
      Database.insertToken(person)
  }
}


fun assertNoException(block: () -> Unit) =
    block() !: throw Error("No exception is expected")

(_: Throwable)

value class Age(value: Int)

val age = Age(42)
println(age) // AUTOBOX DISABLING REQUIRED

IrElementTransformer

age

IrGetValue

program

fun interface Context1 {
    fun c1(): Int
}

fun interface Context2 {
    fun c2(v: Int): String
}


context(Context1)
fun useC1(): context(Context2) (Int) -> String {
    val x = c1()
    return { c2(it + x) }
}

fun main(args: Array<String>) {
    val program: context(Context2) (Int) -> String = with(Context1 { 42 }) {
        useC1()
    }

    //this works
    val result = program(Context2 { "the value is $it" }, 2)
   
    //but this doesn't work
    with(Context2 { "the value is $it" }) {
        program(2)
    }
}

"-Xallow-kotlin-package"

-Xbackend-threads=4

compileKotlin {
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_11
        freeCompilerArgs = ["-Xuse-k2", "-Xbackend-threads=4"]
    }
}

_η_−1

ϕ

suspend fun <ReaderType, ReturnType> registerCallback(listener: (((ReaderType) -> Unit)?) -> Unit, func: (ReaderType) -> ReturnType): ReturnType {
    return suspendCoroutine<ReturnType> { block ->
        listener { btr ->
            block.resume(func(btr))
            listener(null)
        }
    }
}

val reader = registerCallback(acsBluetoothReaderManager::setOnReaderDetectionListener) { reader ->
  [...]
  reader
}

java.lang.ClassCastException: org.reactormonk.debugapplication.BluetoothSupportKt$registerCallback$2$1 cannot be cast to com.acs.bluetooth.BluetoothReaderManager$OnReaderDetectionListener
        at org.reactormonk.debugapplication.BluetoothNFCActivity$onCreate$1$reader$1.invoke(BluetoothNFC.kt:72)

public void setOnReaderDetectionListener(BluetoothReaderManager.OnReaderDetectionListener listener) {
        this.b = listener;
    }

    public interface OnReaderDetectionListener {
        void onReaderDetection(BluetoothReader var1);
    }