Kotlin v2.4.0-RC

Changelog

Backend. J2KLIB

• KT-84877 [J2KLIB] Remove withKotlinBuiltinsHack present in JKlibIrLinker.kt
• KT-85846 Tests failing with fake override property missing accessors or backing field
• KT-85717 IllegalStateException due to already bound symbol
• KT-86204 [JKlib] Propagate private members from dependecies in the IR tree

Compiler

• KT-86210 Update -Xannotation-default-target CLI parameter doc
• KT-85948 Contracts in 2.4 stdlib is not compatible with 2.3 compiler
• KT-85957 Contract on function is getting discarded if any of effect declarations is unknown
• KT-86130 False positive UNINITIALIZED_ENUM_COMPANION on LV 2.3 and lower
• KT-84860 False positive UNINITIALIZED_ENUM_COMPANION in enum access with explicit receiver in enum initializer when enum class has a companion
• KT-84319 Add JVM target bytecode version 26
• KT-85825 Context parameter lambda loses context type when wrapped in nested run blocks
• KT-84960 Property contract leaks unsubstituted type parameter in smart cast

Compose compiler

• b/509945632 Do not generate groups in inline lambdas without @Composable calls

IR. Interpreter

• KT-86083 Create a new CLI flag to enable IntrinsicConstEvaluation feature

JVM. Reflection

• KT-86017 KClass.constructors returns all java.lang.String constructors for mapped type kotlin.String
• KT-85999 Reflection: ByteArray KType incorrectly has type arguments in Kotlin 2.4.0

Libraries

• KT-86027 Hide returnsResultOf under a separate flag and remove its usages from kotlin stdlib

Native

• KT-84733 LLVM Update: rebase LLVM once the upstream stabilizes

Tools. Compiler Plugin API

• KT-85969 KtLint incompatible with Kotlin 2.4.0-Beta2 (parsing errors / Extensions storage issue)

Tools. Compiler Plugins

• KT-86170 PowerAssert: Stabilize runtime ABI for initial release
• KT-85250 PowerAssert: Automatically add runtime library dependency

Tools. Compiler plugins. Serialization

• KT-85554 Serialization: "IndexOutOfBoundsException" on property generated by Compose plugin
• KT-85963 IncompatibleClassChangeError: Expected non-static field $stable on deserialization of @Serializable data class when Compose compiler plugin is applied before Serialization plugin

Tools. Gradle

• KT-85373 Compile against Gradle API 9.5.0
• KT-85374 Run tests against Gradle 9.5.0

Tools. Gradle. Multiplatform

• KT-85877 The number of SPM direct dependencies is multiplied on number on targets
• KT-85706 SwiftPM Import: Updating package version in build script updates version in the lock file
• KT-83370 Incorrect metadata transformation for stdlib's webMain source set

Tools. Gradle. Native

• KT-85984 linkReleaseFrameworkIosSimulatorArm64 is executed during Debug iOS build since 2.4.0-Beta2
• KT-86024 Empty main compilations cause w: [COMPILER_ARGUMENTS_WARNING] There are libraries in -friend-modules CLI argument that are not included in -library CLI argument:

Tools. Gradle. Wasm

• KT-85974 K/Wasm: Do not set -Xir-per-module for Wasm tasks