Changelog

Analysis API

• KT-80082 K2. False positive "Cannot resolve method" for self-bounded generic with wildcard return type in Java interop

Analysis API. Code Compilation

• KT-70860 K2 IDE / Kotlin Debugger: CCE “java.lang.String cannot be cast to java.lang.Void” on evaluating not-null variable on the line with assigning null to that var

Analysis API. FIR

• KT-81378 Expected expression 'FirFunctionCallImpl' to be resolved caused bysuspend {}
• KT-80473 Add events for tracking LL activities

Analysis API. Providers and Caches

• KT-81476 Analysis API:AlreadyDisposedException from low-memory cache cleanup
• KT-80911 Analysis API: Execute session invalidation in a non-cancelable section
• KT-81242 Analysis API: Add UUID/lifetime properties to LL FIR session structure logging
• KT-80622 Analysis API: Visualise LL FIR session structure & weight
• KT-80904 Analysis API: "Invalid dangling file module" exception during session invalidation
• KT-78882 K2 AA: Calling containingSymbol on getProgressionLastElement causes exception

Analysis API. Standalone

• KT-81108 AA: java.lang.ClassCastException: class org.jetbrains.kotlin.fir.FirBinaryDependenciesModuleData cannot be cast to class org.jetbrains.kotlin.analysis.low.level.api.fir.projectStructure.LLFirModuleData

Analysis API. Stubs and Decompilation

• KT-77097 SupportReplaceWith deprecation annotation argument via stubs

Analysis API. Surface

New Features

• KT-80084 Provide endpoints for Analysis API to understand when the context sensitive resolution is used

Fixes

• KT-81132 Use KaSession instead of a particular KaSessionComponent for context parameter bridges
• KT-81129 K2: KaSymbolInformationProvider#importableFqName: should return null for dynamic declarations
• KT-81128 K2: KaSymbolInformationProvider#importableFqName: should return null for error destructuring declarations
• KT-81127 K2: KaSymbolInformationProvider#importableFqName: should return null for anonymous functions
• KT-81126 K2: KaSymbolInformationProvider#importableFqName: should return null for enum entry initializer constructors
• KT-81125 K2: KaSymbolInformationProvider#importableFqName: should return null for property accessors
• KT-81124 K2: KaSymbolInformationProvider#importableFqName: type alias constructor should have a reference to the type alias and not to the underlying class
• KT-70127 Analysis API: 'KaFirReceiverParameterSymbol' does not implement 'KaFirSymbol'; leads to exception fromimportableFqName
• KT-81123 Reimplement KaFirSymbolInformationProvider#importableFqName
• KT-81122 Drop KaImportOptimizer
• KT-79772 Migrate from 'validityAsserted' to 'withValidityAssertion'
• KT-59857 KaExpressionTypeProvider#returnType shouldn't throw an exception for class like declarations

Backend. Wasm

• KT-79244 [Wasm] Drop K1-specific tests, testrunners and test directives
• KT-80397 K/Wasm: turn on by default using a new version of the exception handling proposal for wasm-wasi target
• KT-76204 K/Wasm: support generating a wasm module per kotlin module/klib
• KT-81372 K/Wasm: JsException: Exception was thrown while running JavaScript code on Safari 18.2/18.3
• KT-80106 devServer in Kotlin/Wasm overwrites defaults, causing missing static paths

Compiler

New Features

• KT-80837 Warn about extension function with a context shadowed by member
• KT-80031 Check spotbugs's@CheckReturnValue in Kotlin's unused return value checker

Performance Improvements

• KT-81617 Native: casts optimizations pass explodes on deep nested loops
• KT-81340 K/N: severe compilation time degradation after turning on casts optimization pass
• KT-52283 Never ending type inference while compiling Kotlin code with lots of self pointing generics

Fixes

• KT-81618 "Number of arguments should not be less than number of parameters" on JVM on Kotlin 2.3.0-Beta1
• KT-81652 Native: ClassCastException: ApplicationForegroundStateListener.Companion
• KT-74999 K2: KotlinNothingValueException within Extension Function
• KT-81254 "AssertionError: There should be at least one non-stub type to compute common supertype": Parser issue during generic type inference
• KT-80250 ISE: flow for PostponedLambdaExitNode not initialized - traversing nodes in wrong order?
• KT-81186 Only allow local type aliases in REPL/scripts until full stabilization
• KT-80929 IC Native: Undefined symbols on ktor
• KT-81657 K2: put warning about "exposing package-private in internal" under experimental language feature
• KT-81241 Konanc exit while lowering org.jetbrains.kotlin.ir.util.IrUtilsKt.remapTypeParameters
• KT-74819 K2: False-positive overload resolution ambiguity for flatMap inside PCLA
• KT-79506 Contract for getter and setter doesn't work if a property is called from another module
• KT-71420 Report error when reified type parameter is inferred to intersection type
• KT-77727 Move some of the extra checkers to the default list
• KT-81257 Native: "Unexpected boolean predicate" when generating 'static_cache'
• KT-81525 Report REDUNDANT_SPREAD_OPERATOR on (*) instead of argument expression
• KT-81522 Fix Light TreeSPREAD_OPERATOR diagnostic positioning
• KT-77008 K2: Incorrectly force casting to a wrong type
• KT-78127 K2: Too precise inference for if/when with expected type in assignment
• KT-80208 K2: ClassCastException: "class java.util.ArrayList cannot be cast to class java.lang.Void" type inference picks Void for generic function
• KT-79231 Inconsistent InnerClass entry flags for abstract inner enum
• KT-20677 Improve diagnostic about implicit default constructor absence for expected annotation class
• KT-9111 Improve diagnostic for call with access to outer class from nested class
• KT-81385 Missing error of nullable expression in class literal in case of reified type parameter
• KT-81141 Fix FirUnsupportedArrayLiteralChecker to forbid array literals inside non-annotation contexts
• KT-81383 Return type of anonymous function used asrun argument is incorrectly inferred toNothing
• KT-80577 "Return type mismatch" for self-referential types used as generic parameters
• KT-81198 Move type and type parameter annotations from jvm_metadata.proto to metadata.proto
• KT-81057 Wrong handling of boxing during redundant casts optimization
• KT-76479 Backend. JVM: Report errors on exposure of types in inline functions
• KT-81191 K2: "null cannot be cast to non-null type ConeTypeParameterLookupTag" with invalid code
• KT-81115 Allow converting lambda with explicit parameter when assigning to variable of an extension function type
• KT-74588 Redundant checkNotNull intrinsics instructions for Java generic methods
• KT-78390 UnmuteFusStatisticsIT.testKotlinxPlugins() after AtomicFU updateskotlin-metadata-jvm
• KT-79369 Forbid typealiasing for all compiler-required annotations
• KT-76344 Drop language version 1.9 for non-JVM platforms
• KT-69294 K2: ReportCONSTRUCTOR_OR_SUPERTYPE_ON_TYPEALIAS_WITH_TYPE_PROJECTION_ERROR instead ofEXPANDED_TYPE_CANNOT_BE_INHERITED after switching to LV 2.2
• KT-81064 Wrong safe call null check handling during redundant casts optimization
• KT-80871 StackOverflowError on AnnotationTarget.TYPE
• KT-80908 K2: Compiling type annotation with self-annotated vararg fail with exception
• KT-76902 Omit type-use annotations from diagnostics
• KT-70507 Should parentheses prevent from plus/set operator desugaring?

Compose compiler

• b/419049140 Disabled memoization intry blocks
• KT-81081 Generate Compose-specific proguard mappings when Compose compiler plugin is applied.

IDE. Gradle Integration

• KT-46273 MPP: Don't fail import for case of missed platform in source set structure
• KT-46417 [UNRESOLVED_REFERENCE] For project to project dependencies of native platform test source sets
• KT-44845 After update to Kotlin 1.4.30 all external dependencies is unresolved in IDE with kotlin.mpp.enableGranularSourceSetsMetadata=true
• KT-46142 K/N distribution is unavailable from IDE with multiplatform hierarchical project structure enabled

IR. Inlining

Fixes

• KT-81673 False warnings about ABI change in dependencies in library mode in 2.3.0-Beta1
• KT-81713 [Inliner] Compilation of inline function with recursive call applied to TODO() fails with an internal error
• KT-74892 Investigate passing inline lambda as argument of another inline function
• KT-78392 CommonPrefix: Add a way of stopping execution when one of the phases is unsuccessful
• KT-80927 [Native] Review intrinsics with PublishedApi
• KT-81070 [Inliner] kotlin/Any is unbound
• KT-80628 KLIB inliner: Not enough information about the "full" mode
• KT-69516 Double-inlining for Native: Enable visibility checks after 1st phase of inlining
• KT-78673 Make fakeOverrideLocalGenericBase not using red code
• KT-80565 KLIB Inliner: Add a special annotation to prohibit inlining of marked inline functions in stdlib on 1st compilation phase
• KT-79718 KLIB inliner: Emit warning on generation ofpublic synthetic accessor when running in "explicit API mode"

IR. Interpreter

• KT-72356 K2 Native: IllegalStateException when annotation has the same source range as a constant in another file

IR. Tree

• KT-79739 Static synthetic accessors inside generic classes access its type parameters
• KT-78100 Track and annotate internal annotations with@PublishedApi to enable annotation visibility validation
• KT-80825 DropIrSerializationSettings.reuseExistingSignaturesForSymbols setting
• KT-79807 Broken IR tree invariants in IrReplSnippet after FIR2IR
• KT-78856 Refactor LocalDeclarationsLowering to split it in smaller parts

JavaScript

• KT-80401 Kotlin/JS support fordefault export in generated JavaScript
• KT-79928 Allow JsModule/JsNonModule/JsQualifier invocation on per-entity level
• KT-81424 Kotlin/JS: Cannot Get / in a simple running application
• KT-81066 Wasm, JS: Remove redundant logging in compiler output
• KT-79222 K/JS: Allow using Long in exported declarations
• KT-74055 KJS:@JsPlainObject adds JS code even if marked interface is not used

Klibs

• KT-64237 Klib metadata: migrate to using the common annotations instead of klib-specific extensions in the compiler
• KT-80999 Reuse existingIrKotlinLibraryLayout inKotlinLibrary for reading pre-processed functions
• KT-80761 K2: [K/N] Should reported klib usage include inheritance
• KT-80290 Removeif and TODO incountInAsInlinedLambdaArgumentWithPermittedNonLocalReturns
• KT-80298 K/N: one-stage compilation is broken

Language Design

• KT-81561 Update nested type aliases KEEP to reflect local type aliases support
• KT-28850 Prohibit protected visibility in final expected classes

Libraries

• KT-81078 Increase kotlin.io.createTempDir and createTempFile deprecation level to ERROR
• KT-74493 Deprecate String.subSequence(start, end) with error and drop it in the future
• KT-81092 Uuid: support generation of version 7 uuids with a given timestamp
• KT-81043 String.toBigDecimalOrNull rejects strings accepted by String.toBigDecimal
• KT-81477 Uuid.Companion.generateV* are missing SinceKotlin annotation
• KT-80530 Annotate Kotlin/Native stdlib with must-use value/@IgnorableReturnValue when appropriate
• KT-79791 Duration.parse incorrectly handles negative decimal seconds in ISO-8601 format
• KT-72111 Change Duration.parseOrNull logic to not throw exceptions internally
• KT-80431 Remove suppression of "ACTUAL_ANNOTATIONS_NOT_MATCH_EXPECT" from stdlib

Native. C and ObjC Import

• KT-81312 Native: when-Xccall-mode direct is used, mark unsupported declarations with unresolvable symbol name instead of@Deprecated(ERROR)

Native. Swift Export

• KT-80969 Swift Export: Callsuspend function asasync on swift side
• KT-81355 Swift Export: Introduce a flag to turn off coroutines export

Tools. Build Tools API

• KT-81602 BTA: rename KotlinToolchains.jvm@JvmName for a more Java-friendly API
• KT-81321 Deprecate old BTA prototype API
• KT-73090 Gradle 8.11 kotlin compilation fails when run with -Pkotlin.compiler.runViaBuildToolsApi=true
• KT-81130 BTA: using KotlinVersion from stdlib in the API breaks when using isolated classloader

Tools. CLI

• KT-81077 Add JVM target bytecode version 25

Tools. Commonizer

• KT-49735 [Commonizer] :commonizeNativeDistribution fails for projects with two or more same native targets
• KT-47523 MPP: Unable to resolve c-interop dependency if platform is included in an intermediate source set with the only target
• KT-48118 Commonized c-interop lib is not attached to common main source set
• KT-46248 MPP: Compile KotlinMetadata fails with Unresolved reference if only one native platform from shared source set is available

Tools. Compiler Plugins

• KT-81348 Incorrect bytecode mentioning error class/package is generated by kotlinx-serialization when private serializer in another module is not accessible
• KT-81091 [DataFrame] Receivers from FirExpressionResolutionExtension are not resolved in CodeFragment
• KT-80944 FirUserTypeRefImpl cannot be cast to class FirResolvedTypeRef in maven project
• KT-80429 Power Assert with "Run test using: IntelliJ": NoClassDefFoundError (org.jetbrains.kotlin.kotlinx.collections.immutable.ExtensionsKt) during compilation
• KT-64339 Symbol Light Classes: No Arg compiler plugin generates synthethic constructor which is not seen from light classes

Tools. Gradle

New Features

• KT-45161 Gradle: Support registering generated sources with the Kotlin model
• KT-71602 Introduce KotlinTopLevelExtension

Fixes

• KT-81837 Run integration tests against AGP 8.13
• KT-77457 Compile against Gradle API 9.0
• KT-81199 Deprecate "org.jetbrains.kotlin.android" plugin
• KT-81719 Do not register swift export related configurations when it's not required
• KT-75869 KGP JS - Update deprecated constructors
• KT-79047 Gradle compileKotlin fails with configuration cache
• KT-81415 BTA: Duplicate daemons when compiling JVM + JS in KGP
• KT-80950 KGP breaks configuration cache when signing plugin with GnuPG is applied
• KT-67290 Deprecate usage of HasKotlinDependencies inside KotlinCompilation
• KT-80763 Add redirect link to error message when 'org.jetbrains.kotlin.android' plugin is used with built-in Kotlin
• KT-64273 Gradle: remove symbols deprecated after KT-54312
• KT-70251 Gradle: hide compiler symbols in KGP

Tools. Gradle. BCV

• KT-80687 Add description to Gradle tasks [ABI Validation]

Tools. Gradle. Compiler plugins

• KT-81827 Add a switch for mapping file tasks in Compose Gradle plugin

Tools. Gradle. JS

• KT-81009 K/JS, Wasm: Promote deprecation of NPM and Yarn package manager internal functions
• KT-76019 Wasm/JS: Promote phantom-js for Karma deprecation to ERROR
• KT-81005 K/JS, Wasm: Promote deprecation of ExperimentalWasmDsl to Error
• KT-81010 K/JS, Wasm: Promote deprecation of internal JS functions to Error
• KT-81008 K/JS, Wasm: Promote deprecation of ExperimentalDceDsl to Error
• KT-81007 K/JS, Wasm: Promote deprecation of public constructors of JS declarations to Error
• KT-81006 K/JS, Wasm: Promote wasm declarations in "js" package deprecation to Error
• KT-81004 K/JS, Wasm: promote deprecation NodeJsExec.create to Error
• KT-75621 KJS / Gradle: Disable npm in --offline mode

Tools. Gradle. Multiplatform

Fixes

• KT-81200 Deprecate 'androidTarget'
• KT-81060 KMP stores common compilation dependency resolution in Configuration cache leading to error when deserializing (Android only)
• KT-77367 [uklib] Project dependency to kotlin-jvm module leads to failure in transform during IDE import
• KT-61127 Remove scoped resolvable and intransitive DependenciesMetadata configurations used in the pre-IdeMultiplatformImport IDE import
• KT-81434 [uklib] androidCompileClasspath resolves java compatibility variant instead of android for uklib library
• KT-81249 Kotlin 2.2.20 broke KMP implementation of Parcelize
• KT-77066 Promote kotlinArtifacts deprecation to an error
• KT-74955 Remove resources resolution strategy completely
• KT-55312 Replace "ALL_COMPILE_DEPENDENCIES_METADATA" configuration with set of metadata dependencies configurations associated per set
• KT-52216 HMPP / KTOR: False positive "TYPE_MISMATCH" with Throwable descendant
• KT-55230 Remove metadata dependencies transformation for runtimeOnly scope

Tools. Gradle. Native

• KT-81134 Native: Gradle configuration failure likely related to Klibs cross-compilation
• KT-77486 Remove bitcode DSL
• KT-77732commonizeCInterop failed with "Unresolved classifier: platform/posix/size_t"
• KT-80675 Commonized cinterops between "test" compilations produce an import failure

Tools. Gradle. Swift Export

• KT-81465 Swift Export package is build with wrong target
• KT-81460 [KGP] Crash in SwiftExportRunner due to older stdlib

Tools. Kapt

• KT-80843 K2: KAPT: Crash on any data class with duplicate properties: "Sequence contains more than one matching element"
• KT-71786 K2Kapt: Stubs generation does not fail on files with declaration errors

Tools. Maven

• KT-81414 2.2.20 regression: OOM (Compressed class space) when in-process
• KT-78201 Maven: migrate JVM compilation to the new BTA
• KT-81435 Maven: Improve BTA classloader reusage
• KT-81218 Kotlin Maven Plugin 2.2.20: Java classes not resolved with enabled incremental compilation without daemon

Tools. REPL

• KT-80062 ReplSnippetLowering sometimes produces IrConstructorCall with too many arguments

Tools. Scripts

• KT-80071 Kotlin script mode produces invalid IR: "value that is not available in the current scope"

Tools. Wasm

• KT-81313 K/Wasm: update Node.js to 24.x
• KT-81315 K/Wasm: update Node.js to 25.x