Kotlin 2.4.20-Beta1

Changelog

Analysis API

• KT-85418 Implement an API for accessing deserialized file annotations in Analysis API
• KT-74448 K2. False positive MISSING_DEPENDENCY_SUPERCLASS in LinkedListTest.kt, kotlinx.coroutines
• KT-85856 containingSymbol of constructor property differs for local and non-local classes

Analysis API. Code Compilation

• KT-76457 K2 IDE / KMP Debugger: KISEWA “Cannot compile a common source without a JVM counterpart” on evaluating inline fun from common module inside jvm

Analysis API. FIR

• KT-70552 No expects for actual
• KT-86014 Types are broken after remove parameter through change signature
• KT-86363 KotlinIllegalArgumentExceptionWithAttachments: No dangling modifier found on companion blocks
• KT-86147 Drop kotlin.parallel.resolve.under.global.lock registry key
• KT-85543 Avoid lazy resolve for the contracts phase if no constracts might be resolved

Analysis API. Infrastructure

• KT-86186 Analysis API: Codebase tests run twice in some analysis modules — pick a single JUnit runner and migrate
• KT-85360 Drop kotlin-compiler-testdata-for-ide artifact
• KT-85585 Simplify the dependencies graph for the Analysis API modules
• KT-85381 Remove tests for the FE10 implementation

Analysis API. Light Classes

New Features

• KT-84645 Support resolving to companion block members & extensions from Java (light classes)
• KT-80775 Support PsiClass#getRecordComponents in light classes

Fixes

• KT-57537 SLC: propagate default parameter value from (@JvmOverloads) expect declarations to actual declarations
• KT-63568 Symbol Light Classes: KtAnnotationApplicationWithArgumentsInfo.normalizedArguments() may work incorrectly when psi is not set
• KT-70428 AA: good code is red when a Java class extends a Kotlin class implementing MutableList by delegation
• KT-36740 MPP: False-positive incompatible types in .java when using expect-class returned by non-expect member from common when actual is actual typealias
• KT-67749 Analysis API: Symbol Light classes should be available only to pure JVM sources
• KT-85040 [Analysis API] Improve Java / Kotlin interop in KMP projects
• KT-68169 K2 IDE. KMP. False positive type mismatch in java file of jvm source-set when using common declaration which expects String
• KT-37783 KMP Java Interop: JVM-only methods on actual superclass not resolved in Java for common subclass
• KT-40059 Provide type correction for expect/actual types used from Java-code
• KT-71429 MPP: False positive "Function1 is not a functional interface" when calling code from Common in Java
• KT-70426 SLC: kotlin.Collection#size is not exposed by default
• KT-60480 Symbol Light Classes: Classes implementing kotlin.collections.* interfaces don't implement all methods from the corresponding java.util.* interfaces
• KT-36991 IDE: "both methods have same erasure" for Java classes directly or indirectly extending Kotlin collections
• KT-22594 KotlinCollection.getSize is not highlighted as an error in Java

Analysis API. PSI

• KT-85052 Move mutation methods out of the Kotlin PSI
• KT-84925 Move KtReference to the Kotlin IntelliJ plugin
• KT-85427 Use factory-like pattern instead of reflection in KtNodeType
• KT-84789 Ensure all KtClassBody.parent usages are correct
• KT-85154 PSI: "AE: parent is ERROR_ELEMENT" with top-level destructuring declaration

Analysis API. Providers and Caches

• KT-82220 Analysis API: Support platform-specific session components and checkers in metadata sessions
• KT-82731 Analysis API: Limit granular tree change processing to a few files

Analysis API. Standalone

• KT-85112 AA does not see packages from unpacked klibs
• KT-86417 Support parameters in 'getExpectsForActual()'
• KT-84916 Metadata stub deserializers aren't properly set up for Analysis API Standalone
• KT-83191 Analysis API: JvmDependenciesIndexImpl performs very poorly for large classpaths

Analysis API. Stubs and Decompilation

• KT-86520 KotlinDeclarationInCompiledFileSearcher doesn't support visibility-mangled declarations
• KT-64901 Inconsistency between AST and Stub tree in the case of non-local destructuring declarations
• KT-84444 Support stubs for companion blocks & extensions

Analysis API. Surface

New Features

• KT-73214 Add KaScope#declarations with name filter
• KT-69085 Provide API to retrieve label/name from KtFunctionLikeSymbol
• KT-70771 KaLocalVariableSymbol: support isDelegatedProperty
• KT-85239 Streaming version of collectDiagnostics()
• KT-85037 Add API for KaFunctionType's returnType modification
• KT-80460 AA: Introduce KtExpression.isStableForSmartCasting API
• KT-82519 Automatically recognize the appropriate analysis mode for in-memory file copies based on their content
• KT-65912 Analysis API: Implement type building API for all KtType

Fixes

• KT-66039 K2: Analysis API: redesign resolution API
• KT-70794 K2 IDE: Reference to object does not resolve as LHS in "plusAssign" assignment expression
• KT-70774 Unary operators on literals are not resolvable
• KT-86757 Flaky annotations result for @all annotation on a backing field
• KT-85382 Remove the FE10 implementation
• KT-86681 [Analysis API] Move isDelegated to KaVariableSymbol
• KT-86685 collectCallCandidates works incorrectly for a constructor vs. a companion invoke
• KT-86514 No expected type within collection literal in annotation entry using array rather than varargs
• KT-76076 K2 AA: safe call expression navigates to parent array index access expression
• KT-86418 Support property accessors in 'getExpectsForActual()'
• KT-71312 KaFirPsiJavaClassSymbol.{hasAnnotations, annotationSimpleNames} is inconsistent with FirJavaClass implementation
• KT-86394 Resolve from KDoc reference is inconsistent with source code
• KT-86248 isUsedAsExpression true for typealias lhs in ::
• KT-85778 Analysis API: Ensure that all public endpoints in implementation modules are internal or opt-in
• KT-78285 resolveToCallCandidates inconsistent behaviour with invoke operator and constructor
• KT-85852 CCE in buildClassType
• KT-85989 Super type references should be aware of type alias constructors
• KT-84184 [Analysis API] Provide a unification substitutor API
• KT-84584 Support companion extensions and blocks in the Analysis API
• KT-84932 Deprecate utilities exposed through analysis-internal-utils
• KT-73059 Consider dropping of KaOriginalPsiProvider
• KT-84737 KaCallableSymbol#directlyOverriddenSymbols doesn't work for java overrides of kotlin properties
• KT-71101 [AA] Consider getting rid of KaTypeNullability

Backend. J2KLIB

• KT-86368 [JKLIB] MetadataJVMModuleDeserializer tries to deserialize all symbols
• KT-86367 [JKLIB] kotlin.Cloneable built-in class not found

Backend. Native. Debug

• KT-85264 [Native] Stepping trace starts with // test.kt:1 box in some debug stepping tests
• KT-81740 Native: importing konan_lldb.py to lldb prints a warning

Backend. Wasm

Fixes

• KT-83159 K/Wasm: generate one common base class fun interfaces (including Function*)
• KT-86123 [Wasm] Callable reference refactoring (KT-83159) broke klib binary compatibility with libraries compiled by Kotlin 2.0.x
• KT-83171 K/Wasm: Investigate import.meta usage in mjs files
• KT-84267 K/Wasm: init order of companion objects is different from JVM
• KT-86192 K/Wasm: Raise a warning on usage of top-level require in JsFun
• KT-83356 K/Wasm: Difference in behavior on nested class initialization (for enums?)
• KT-71505 [Wasm, IC] Incremental step can produce wrong main function call
• KT-86822 K/Wasm: don't cast the result of calling callable references with Unit return type
• KT-86180 [Wasm] backward compatibility is broken in 2.1->2.2 by changed order of type parameters
• KT-86640 [wasm]: Single-module test failures with companion object initializers
• KT-71039 [Wasm, IC] Investigate synthetic function types loading
• KT-66105 Wasm: SyntaxError: Identifier 'box' has already been declared
• KT-82843 K/Wasm: pass a lambda call helpers to convert funs as an argument instead of exporting them
• KT-83245 K/Wasm: Run stepping tests with local variables with K/Wasm
• KT-86166 [Wasm] Make possible to have passing test in multimodule but having it fail in monolith
• KT-84667 wasm: Add general support for custom sections/annotations
• KT-85506 [Wasm/WASI] Stdlib readLn and readlnOrNull implementation
• KT-85270 K/Wasm: incremental compilation fails with NoSuchElementException when a stdlib call is removed

Compiler

New Features

• KT-86410 [KMP] Implement acceptance of JVM IC metadata from previous compilation
• KT-84295 Support Companion Block of Operator for Collection Literals
• KT-86657 Native: turn on incremental compilation by default
• KT-84956 Resolve of references to static & companion object members of generic class
• KT-86409 [KMP] Create JVM IC metadata output
• KT-85593 ELA: Support multiple lambda arguments
• KT-84618 Emit a warning when an undesrcore variable is assigned to a Unit expression
• KT-83040 Collection literals: ensure normal interaction with CFG
• KT-84333 Collection literals: type inference in delegate expression
• KT-84289 Resolution to Companion Block & Extension Invoke Operator
• KT-82961 Type inference from upper type for type parameters designed for tracking of checked exceptions
• KT-81444 False positive: "Overload resolution ambiguity" with @OverloadResolutionByLambdaReturnType and multiple lambda parameters
• KT-84393 Support Unit-conversions and Unit-adaptations for arbitrary expressions in argument positions
• KT-84319 Add JVM target bytecode version 26

Performance Improvements

• KT-69758 FastJarFS - avoid copying data on inflating (JDK 16+)
• KT-85647 Compilation performance regression in AbstractFirDeserializedSymbolProvider since 2.3.20
• KT-86104 [JVM] use static methods/fields of KTypeProjection in typeOf generated bytecode
• KT-86084 IDEA freezes when a lot of properties are modified to lazy delegates
• KT-83068 Investigate long compilation times with many generics & overloads
• KT-66469 Long compilation with mockk import
• KT-79677 Remove meaningless LVT records

Fixes

• KT-84802 Add new synthetic class flag to JVM metadata
• KT-83766 K2: Wrong sourcePsi is set for SymbolPsiLiteral in SLC for annotation arguments referencing a const val
• KT-86728 Reified type inference: expected type not propagated into inline call inside lambda with elvis operator
• KT-82510 K/N, IC: "Undefined symbols for architecture arm64" for iosSimulatorArm64 with kotlin.incremental.native=true
• KT-84185 Type arguments are wrongly allowed in receivers of static calls
• KT-84154 Invalid qualifiers with type arguments in package parts compile without diagnostics
• KT-80227 Support unnamed context parameters in evaluation
• KT-86751 IntroducedAt: Do not generate @IntroducedAt overrides as synthetic
• KT-85816 Drop remaining usages of ComponentRegistrar
• KT-86534 Extract reworked annotations resolution under separate language feature
• KT-84626 Try to combine FirConstChecks and FirExpressionEvaluator
• KT-85291 MFVC: consider analyzing the type of declaration instead of use-site target in AnnotationChecker
• KT-86755 False negative NATIVE_SPECIFIC_ATOMIC in type arguments
• KT-86752 K2: False negative NO_REFLECTION_IN_CLASS_PATH on type parameters, intersection types, captured types
• KT-85972 [ArrayEqualityCanBeReplacedWithContentEquals checker] Checker misses smart-cast array operands when the original type is a type parameter
• KT-85970 [ArrayEqualityCanBeReplacedWithContentEquals checker] Warning message mentions ==/=== instead of !=/!== for inequality operator
• KT-86705 False positive REDUNDANT_SINGLE_EXPRESSION_STRING_TEMPLATE for nullable String? expressions with -Wextra
• KT-86798 Native: don't use stale incremental cache when a new compiler version is used
• KT-86524 JvmExposeBoxed: Collection does not implement abstract method
• KT-86526 JvmExposeBoxed: Sequence contains more than one matching element
• KT-86298 LEAKED_IN_PLACE_LAMBDA when a lambda parameter is forwarded into an inline function parameter
• KT-76632 K2: False positive "Assigned value is never read" with 'flatMap()'
• KT-86699 Kotlin/Native: get rid of OptimizeTLSDataLoads
• KT-86646 IllegalStateException "unknown supertype kind null" when compiling data class with definitely non-nullable type parameter (U : T & Any)
• KT-86662 Check for loss of ConeIntersectionType.upperBoundForApproximation
• KT-86629 Approximation of Intersection Type to Upper Bound is Broken by Bang Bang Operator
• KT-86115 Platform declaration clash on no-arg constructor with @JvmExposeBoxed and @IntroducedAt
• KT-78079 Enable generation of when using invokedynamic by default for JVM targets 21+
• KT-86643 Warning for returning callsInPlace lambda
• KT-86609 Make KDocSection implement PsiLanguageInjectionHost
• KT-86642 Flexible type with nullable intersection types in both bounds
• KT-85148 Native: check/fix KT-72710 Incorrect behaviour of tail call suspend functions optimization
• KT-85641 Nullable-marked object qualifiers in LHSs of callable references
• KT-86464 Support isPublicAbi JVM metadata flag for anonymous and synthetic local classes
• KT-82216 Sanitize '.kotlin_module' filename
• KT-85230 False negative deprecation diagnostics on import of member of nested class
• KT-62467 K2: Result type of elvis operator should be flexible if rhs is flexible
• KT-86319 K2: StackOverflowError in AbstractConeSubstitutor with recursive Java type bound under mixed JSpecify @NullMarked/@NullUnmarked
• KT-86512 K2: Bad IR for adapted callable reference to function with generic vararg and optional parameter
• KT-77726 Move FirUnusedExpressionChecker to the default checkers list
• KT-85947 Collection literals: internal failure when SAM is expected
• KT-85842 Collection literals (and CSR): internal failure when lambda is analyzed during inference of outer call
• KT-85535 Collection literals: Migrate to new resolve in annotations under "-Xcollection-literals"
• KT-84559 @OptIn on collection literal and context-sensitive does not work
• KT-86468 K2: False negative DSL_SCOPE_VIOLATION when type parameter has DSL-annotated bound
• KT-86292 False negative: INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING reported for direct getValue call but not for equivalent by delegation
• KT-86467 K2: False negative ILLEGAL_RESTRICTED_SUSPENDING_FUNCTION_CALL with DNN, flexible, captured and intersection receiver types
• KT-85848 Recursion on value classes through type parameters
• KT-75874 K2: Adjust the type mismatch diagnostic on lambda parameters
• KT-86110 K/N Incremental compilation: stale cache is reused after enum entry reorder
• KT-82456 K2. Missing deprecation for object with invoke
• KT-85656 [NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS] False negative for nested type alias
• KT-86184 KDoc: syntax highlighting incorrect when @param, @return, or summary line begins with a backtick
• KT-85454 Make :compiler:android-tests:test cacheable
• KT-85955 Implicit JvmExposeBoxed: double default constructor parameter leads to IOOBE
• KT-51400 Additional independent candidate with @OverloadResolutionByLambdaReturnType could change inference results
• KT-86042 Inference fixes lambda's return type variable too early
• KT-86327 Add flag to LanguageFeature enum to enable it in the latest language version tests
• KT-86133 K/N IC: stale cache is reused after reified inline body change
• KT-84718 Provide information for simple names resolved through imports which might be resolved via context-sensitive in IDE mode
• KT-75112 FE resolves wrong receivers order for property passed to delegate
• 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-85300 Improve message for UNRESOLVED_REFERENCE_WRONG_RECEIVER
• KT-80590 Drop language version 1.9 for JVM
• KT-86191 Check not null on a dynamic-typed property leads to malformed CFG
• KT-85957 Contract on function is getting discarded if any of effect declarations is unknown
• KT-86143 operator keyword is allowed on arbitrary equals in enum entries
• KT-73197 Order-dependent choice of overload by lambda return type with Unit
• KT-86144 Unresolved code in ambiguous plus assign is not reported
• KT-86006 CFG: Exponential growth when visiting unresolved delegates in FirLocalVariableAssignmentAnalyzer
• KT-86103 Incorrectly reported CONFLICTING_OVERLOAD on companion member
• KT-84344 Disambiguate fake source elements for source-based symbol IDs
• KT-85965 Native: incremental compilation blows up with NoSuchFileException: class_fields
• KT-86005 Fix misuse of DeferredMethodVisitor.intermediate in AnonymousObjectTransformer
• KT-72840 [JVM Inliner] Two fails AFTER mandatory stack transformations: incorrect bytecode
• KT-30728 "VerifyError: Operand stack underflow" on crossinline lambda usage inside inline function in anonymous object
• KT-84589 Prohibit Array<Nothing> in lhs of ::class
• KT-85825 Context parameter lambda loses context type when wrapped in nested run blocks
• KT-84766 Kotlin/Native: separate compiler cache for latin1Strings=true
• KT-82899 Native IC: AIOOBE on coroutines
• KT-85188 Don't poison binaries with companion blocks & extensions for LV >= 2.5
• KT-80176 ASSERT FAILED: SDE.c : 296 - bad SourceDebugExtension syntax - position 376 - expected ':'
• KT-84581 Inline function with @JvmOverloads produces SourceDebugExtension attribute with invalid line numbers
• KT-85954 Implicit JvmExposeBoxed leads to IOOBE when data class constructor accepts nullable inline class
• KT-84960 Property contract leaks unsubstituted type parameter in smart cast
• KT-85203 Kotlin/Native: "Invalid LLVM module - Instruction does not dominate all uses" with nested inline suspend functions and withContext
• KT-84280 Standalone Unit qualifier allows type arguments: Unit<Any>
• KT-85766 Confusing error message "'this' is not defined in this context" on companion extension delegated property
• KT-72706 Confusing "INVISIBLE_REFERENCE" when calling private constructor
• KT-85888 Native: incremental compilation blows up when a method changes from open to final
• KT-85720 K2: Missing null check in generic vararg function call when passing value of flexible type
• KT-85701 K2: Type parameter is out of bounds for IMPLICIT_DYNAMIC_CAST
• KT-80841 Confusing positioning of NO_VALUE_FOR_PARAMETER
• KT-82196 False positive: "Recursive call is not a tail call" inside when/if with lambda and elvis
• KT-85841 Error message for NULLABLE_ON_DEFINITELY_NOT_NULLABLE uses obsolete term for DNN types
• KT-81932 False positive TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED caused by try in another branch inside tailrec function
• KT-85661 Lazy resolve for substituted property accessors with a contract doesn't work
• KT-84719 Provide information for qualified types that might be replaced with context-sensitive simple names in IDE mode
• KT-85667 Add experimental language version 2.6
• KT-85770 Support companion block properties in interfaces
• KT-85168 Generate static initializers as proper IR functions
• KT-85703 Drop pre-2.0 language features from K2 & common compiler code
• KT-74516 False negative TYPE_PARAMETER_AS_REIFIED for DNN type
• KT-85733 Illegal unqualified resolution to companion extension through scope linking
• KT-85679 Internal Compiler Error when trying to access a value parameter from companion block
• KT-81814 Field name '$$context-Functor#1' cannot be represented in dex format
• KT-81708 K/N incremental compilation: No module deserializer for FUN name:writeObject
• KT-6071 Change USELESS_CAST warning message
• KT-85527 Unmute Android tests after removing IGNORE_BACKEND_K1 directive
• KT-84939 Kotlin/Native: support llvm passes in -Xsave-llvm-ir-after
• KT-85341 K2."TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM" false positive on accesses to properties of an anonymous object
• KT-84861 Support Companion Blocks & Extensions in Scripts/REPL
• KT-72999 K/N: Do not consider IrTypeOperatorCall as a tail call expression
• KT-84327 Name-based destructuring conflicts with in-scope functions
• KT-78678 Checking for nullable type against nullable type falls back to inline-when generation mechanism
• KT-83652 Confusing messages when using package parts with type arguments in qualifiers
• KT-85479 Improve diagnostic messages for upper bound violations
• KT-84717 Provide information for qualified expressions that might be replaced with context-sensitive simple names in IDE mode
• KT-84859 Skip deprecation phase for generic arguments in qualifier receiver of static call for companion block members and extensions
• KT-75372 Deprecate K1 compiler
• KT-80093 Type inference depends on the presence of transitive dependency
• KT-68933 CompilationException: Back-end: Could not get inlined class
• KT-70461 K2: "Inline class types should have the same representation" caused by value class and smart check
• KT-63746 K2: JSpecify: If a class has a @Nullable type-parameter bound, Kotlin should still treat unbounded wildcards like platform types
• KT-17738 Java cannot extend class implementing kotlin.collections.Map

Compose compiler

• b/489339299 Move Compose runtime to a stable version
• b/509945632 Always wrap inline lambdas with a composable group with a group
• b/422193018 Cherry-pick "Fix callableInferenceNodeOf in ComposableTargetChecker.kt"

IR. Inlining

• KT-85605 "Local delegated property has not delegate" exception when calling inline function containing delegated property in a lambda from within an inline lambda
• KT-79065 Try to remove NativeRuntimeReflectionIrBuilder
• KT-72464 [Native][JS][Wasm] Non-local return through suspend conversion breaks the IR inliner

IR. Interpreter

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

IR. Tree

• KT-86527 Remove unreachable code from UpgradeCallableReferences
• KT-85673 Replace classId with IrClassSymbol in IrAnnotation
• KT-85572 KLIBs: New signatures for companion funs/vals
• KT-74938 Use SYNTHETIC_OFFSET in IR fake overrides
• KT-78175 Remove remaining usages of attributeOwnerId outside of JVM backend
• KT-85573 Store "companion parameter" in IR of funs/vals declared as companion extensions
• KT-85896 Type parameter is out of bounds (in setter) for a property with context parameters
• KT-85698 Type parameter is out of bounds (in setter) for an extension property with type parameter
• KT-76934 Drop old IR parameter API

JVM. Reflection

New Features

• KT-73657 Fix kotlin-reflect performance issues for reflection operations common for both reflection implementation: stdlib and kotlin-reflect

Fixes

• KT-86709 Reflection: KRIE with Reaktor on fresh master
• KT-85903 Reflection: do not inherit companion block members from supertypes in KClass.members
• KT-85902 Reflection: support call/callBy for companion blocks & extensions
• KT-86477 Reflection: test builtin class contents
• KT-86545 Reflection: extra Serializable supertype for non-mapped enum classes in "kotlin" package
• KT-83677 Reflection: aliased extension function type is rendered as non-extension in toString
• KT-85836 Reflection: KotlinReflectionInternalError on isSubtypeOf with definitely-not-null type
• KT-83986 Reflection: java.io.Serializable is not shown in supertypes of Int type in new reflection
• KT-84495 Reflection: "KotlinReflectionInternalError: Annotation class not found: kotlin/jvm/internal/EnhancedNullability" on Java Optional type
• KT-86017 KClass.constructors returns all java.lang.String constructors for mapped type kotlin.String
• KT-85550 Reflection: KParameter.type.classifier returns boxed KClass for non-nullable primitive types
• KT-86177 Reflection: incorrect modality of Java constructors in the new implementation
• KT-85999 Reflection: ByteArray KType incorrectly has type arguments in Kotlin 2.4.0

JavaScript

New Features

• KT-56493 KJS: Export documentation to generated d.ts files
• KT-51292 Proposed behavior of @JsExport on interfaces and classes with companion objects
• KT-21626 Support ES2015 syntax in js function

Fixes

• KT-80188 Design exporting of suspend lambdas into JS/TS
• KT-84710 Kotlin/JS: Suspending default interface methods are not accessible on subclasses from JS
• KT-19819 JS: source maps: write the longest common prefix of all paths to "sourceRoot" field
• KT-85990 K/JS: Default parameter values ignored in @JsStatic suspend functions when class is exported
• KT-82266 Support transitive export in Analysis API-based TypeScript export
• KT-85616 [K/JS] Add synthetic and internal compiler APIs into sourcemap's ignoreList
• KT-84090 Save variance in the generated TypeScript
• KT-56618 KJS/IR: Support external interfaces from common code (via annotation?)
• KT-80991 K/JS/Wasm interop: JsReference.get is easy to accidentally use in JS target
• KT-85424 Replace each js call with jsClassIntrinsic after bootstrapping
• KT-84457 KJS: Support implementable interfaces in Analysis API-based TypeScript Export
• KT-85452 K/JS: Cannot create static member with @JsStatic in non-companion object
• KT-83462 Usage of star projection makes any generic type not-exportable
• KT-85599 Allow exporting annotation classes into JS/TS
• KT-85563 Kotlin/JS: TypeScript mts files do not properly escape enum values
• KT-85411 Fix conversionCombinations.kt tests for the JS target
• KT-60899 K2 JS: Implement warning NO_REFLECTION_IN_CLASS_PATH

Klibs

Performance Improvements

• KT-84837 Introduce an index in IR linker for faster look up of suitable module deserializers

Fixes

• KT-86501 Native: IrTypeAliasSymbolImpl is already bound. Signature: kotlinx.datetime/Instant|null[0] on iosSimulatorArm64
• KT-85578 KLIBs: New manifest property to indicate "new initialization order"
• KT-84836 Minimize usages of IrBuiltIns in the KotlinIrLinker
• KT-86037 [Tests] Split test directive IGNORE_KLIB_BACKEND_ERRORS_WITH_CUSTOM_FIRST_STAGE
• KT-81947 [Wasm] Klib backward and forward compatibility testing
• KT-86228 Simplify Klib's ReadBuffer
• KT-58409 [KLIB Reproducibility] File path separators should be platform-independent in KLIBs
• KT-78188 [JS] Klib backward and forward compatibility testing
• KT-76195 Combine toJvmMetadataVersion and toKlibMetadataVersion
• KT-84750 [K/N] Set "kotlin.native.home" appropriately in forward testing of master -> 2.4.0-Beta2
• KT-85805 AtomicfuNativeKlibSyntheticAccessorTestGenerated broken
• KT-85359 ExportKlibToOlderAbiVersion with LV=2.2 is silently ignored
• KT-85290 Make :native:native.tests:klib-compatibility:testMinimalInAggregate cachable
• KT-85080 Klib/IR Tests TC configuration -- need to explicitly download the necessary dependencies
• KT-84990 Investigate the usage of allDependencyModules in IR linker
• KT-84349 [Wasm] Implement forward klib compatibility testing

Language Design

• KT-86089 Explicit context arguments: Stable release
• KT-86201 Name-based destructuring stable release of only-syntax in 2.5
• KT-7882 Generic vs Non-Generic and implicit Unit return type
• KT-78796 Decide the future of the AllowEagerSupertypeAccessibilityChecks language feature
• KT-73821 Decide the future of the ForbidUsingSupertypesWithInaccessibleContentInTypeArguments language feature

Libraries

New Features

• KT-86595 Introduce StackTraceRecoverable interface into the standard library
• KT-10380 allEqual function for Iterable

Performance Improvements

• KT-86032 K/N, K/Wasm: BitSet::get allocates objects for each access

Fixes

• KT-86027 Hide returnsResultOf under a separate flag and remove its usages from kotlin stdlib
• KT-86696 return-value-checker: false positive Path.setPosixFilePermissions and Path.setLastModifiedTime
• KT-86470 Stdlib doc: Wrong timestamp in kotlin.time.Instant.parse example (leads to InstantFormatException)
• KT-86053 Update kotlin-metadata-jvm for the companion blocks and extensions
• KT-80654 K/N and K/Wasm: implement missing Regex tests
• KT-85326 Libraries: rangeUntil docs sample code uses a rangeTo example
• KT-82505 API reference: add links to array transformations returning arrays from their list-returning counterparts
• KT-62423 Consider providing Common atomic types

Native

• KT-74844 kotlin.native.internal.FileFailedToInitializeException when running native tests with Kotlin 2.1.20-Beta2
• KT-83914 Native: when loading JNI libraries, java.library.path can contain system directories with libraries with same names

Native. Build Infrastructure

• KT-82607 [K/N] Dist build fails when gradle daemon was started on a JRE (i.e., without JNI headers)
• KT-85451 Native: migrate the remaining tests to testFixtures
• KT-86725 Kotlin/Native: make KonanCacheTask aware of per-file caches
• KT-85803 K/N: build not reproducible - platformLibs caches
• KT-85823 Kotlin/Native: delete outputs in :kotlin-native:distNativeLibs
• KT-85522 Kotlin/Native: llvmLinkBreakpadMainMacos_arm64 fails

Native. C and ObjC Import

• KT-83940 Generate IR from C-interop KLIBs without descriptors
• KT-86871 C-interop Klib caches are not deterministic after KT-83940
• KT-86559 [K/N] More stable @CCall ids
• KT-73656 Native: @OverrideInit on a capturing local class constructor causes a compiler crash
• KT-85765 Prohibit emitting C-interop KLIBs with kotlin or kotlinx.cinterop packages
• KT-84043 Native: findMacros takes a lot of time with -fmodules in cinterop
• KT-85705 Swift-generated headers with external_source_symbol produce duplicate enum declarations

Native. ObjC Export

• KT-86069 Native: the annotation target for @ObjCEnum.EntryName` is wrong
• KT-83504 ObjCExport: Source unresolved dependency
• KT-83505 ObjCExport: Transitive unresolved dependency

Native. Runtime

• KT-85897 [K/N] C Export sometimes hangs on termination on mingw
• KT-85811 K/N: FirNativeGCTestGenerated.testMemoryDump fails
• KT-85882 Performance improvement in Kotlin_getCurrentStackTrace: use vectorized/range-checkless copy
• KT-85077 Native: if CoreSymbolication fails, report this to users with a troubleshooting guide

Native. Runtime. Memory

• KT-85457 Native: TSAN tests fail with Xcode 26.4

Native. Swift Export

New Features

• KT-79477 Make Swift Export work handle @OptIn declarations well

Fixes

• KT-86650 [Swift Export] Trampoulinebuilding for a function with changed argument name produces incorrect code.
• KT-85870 [Swift Export] Invalid unavailability propagation to protocol members
• KT-85918 [Swift Export] unavailable operator function fails to compile
• KT-85869 [Swift Export] release function conflicts with unavailable NSObject.release
• KT-85868 [Swift Export] Factory function conflicts with class name
• KT-85871 [Swift Export] 'AbstractCoroutineContextKey' is inaccessible due to '@_spi' protection level
• KT-85788 [Swift Export] Doesn't resolve generic upper bound
• KT-85534 [Swift Export] Fails to bind private class implementing deprecated public interface
• KT-85784 [Swift Export] generic class with multiple upper bounds fails
• KT-85704 [Swift Export] cannot infer generic type of function returning a generic type
• KT-85711 [Swift Export] suspend function returning non-null generic fails to compile
• KT-85715 [Swift Export] generic interface in typealias fails to compile
• KT-85714 [Swift Export] unsupported input type param in functional receiver
• KT-85458 [Swift Export] value of a closure returning a closure generates invalid swift code

Tools. BCV

• KT-83476 Use Maven publications as dump input [ABI Validation]

Tools. Build Tools API

New Features

• KT-85663 Make BTA JS Compiler Arguments Type-Safe
• KT-66425 BTA: implement ClasspathEntrySnapshot.hashCode
• KT-84598 [BTA] Expose API Version via Public Property
• KT-85421 BTA: validate arguments for invalid characters and guide users to feedback issue
• KT-78207 BTA: implement basic Kotlin/Wasm binaries linking support
• KT-78206 BTA: implement basic Kotlin/Wasm compilation support
• KT-83794 Make BTA JVM Compiler Arguments Type-Safe
• KT-84401 BTA: implement Kotlin/JS incremental compilation support
• KT-78204 BTA: implement basic Kotlin/JS compilation support

Fixes

• KT-82986 BTA: setting unknown options may pass silently
• KT-86734 Add Kotlin 2.4.0 into backward-compatibility tests
• KT-86785 [KGP] Compilation logs are not prefixed with taskPath in BTA mode
• KT-85093 [BTA] Resolve Forward Compatibility Test Blocker for X_IGNORED_ANNOTATIONS_FOR_BRIDGES
• KT-85787 BTA: Distinguish typed argument values from raw string values in compatibility test descriptors
• KT-85504 Kotlin Daemon crashes if there is a typo in compiler args added as key-value freeCompilerArgs
• KT-85736 BTA tests: automate detection of missing versions in compatibilityTestsVersions
• KT-78208 BTA: split Kotlin/JS compilation and linking arguments
• KT-78209 BTA: split Kotlin/Wasm compilation and linking arguments
• KT-86395 [BTA] forward-compatibility violation: NoSuchMethodError on JvmSnapshotBasedIncrementalCompilationConfiguration. breaks IC
• KT-80679 Add support for the Build Tools API [ABI Validation]
• KT-86156 BTA: report all invalid argument values at once instead of stopping at the first one
• KT-85505 Kotlin daemon crashes if "-Xwarning-level=" compiler option is added with a syntax error
• KT-85958 argumentsToStrings produces corrupted arguments when value starts with "@"
• KT-86059 [BTA] Handle enum parsing errors related to case sensitivity
• KT-86243 [BTA] Compat package has wrong version of compiler on compile classpath
• KT-86247 [BTA] Improve -Xjsr305 parser error message: include the full failing entry
• KT-85556 BTA: SearchPathType compiler arguments (classpath, -Xklib, -Xmodule-path) not resolved to absolute paths
• KT-85167 Make Xjsr305 type safe
• KT-86117 CRI: fileId is hashed from the absolute source path, not the stored relative path
• KT-85696 BTA: deepCopy() in JvmCompilerArgumentsImpl uses string round-trip, corrupting delimiter characters
• KT-85738 BTA forward compatibility: NoSuchFieldError on X_IGNORED_ANNOTATIONS_FOR_BRIDGES when API 2.3.0 is used with impl 2.4.0
• KT-85722 [SSoT, JS/Wasm] Switch to "nopack" naming for argument controlling packing of klibs to unify with Native backend
• KT-85702 [SSoT] Simplify compiler argument enum serialization by replacing per-type serializers with a generic contextual serializer
• KT-85607 [BTA] -Xignored-annotations-for-bridges missing forward compatibility support (API 2.3.20 + impl 2.4.x+)

Tools. CLI

• KT-56850 Separate K/Wasm CLI entry point from K/JS CLI
• KT-86202 Warn against disabling a language feature with a parametrized compiler argument that's already stable
• KT-86746 Drop all org.jetbrains.kotlin.asJava usages from CLI
• KT-85813 Inconsistent behavior of -Xcontext-parameters warning depending on daemon/in-process
• KT-85414 Argument DSL: delimiter = KotlinCompilerArgument.Delimiter.PathSeparator generates invalid Kotlin code
• KT-85920 Remove MessageCollector Usage from ErrorReportingContext
• KT-85898 Register all KtDiagnosticsContainers
• KT-85187 Add compiler argument for companion blocks & extensions

Tools. CLI. Native

• KT-85538 Native: allow using JNI in CLI tools on JDK 24+ and Unsafe on JDK 24

Tools. Compiler Plugin API

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

Tools. Compiler Plugins

New Features

• KT-85758 Support for @Log annotation on Kotlin classes

Fixes

• KT-86286 all-open plugin makes @JvmRecord classes non-final, causing compilation error "'@JvmRecord' class must be final"
• KT-86620 Lombok incorrectly detects clashing constructor with varargs argument
• KT-86773 PowerAssert: sorting of possible overloads
• KT-86225 Atomicfu generates IR with out-of-scope type parameters
• KT-83121 Lombok. A constructor without parameters is available for a class with @Data and staticConstructor
• KT-84059 Lombok. CANNOT_INFER_PARAMETER_TYPE for toBuilder function if @Builder is applied to a generic class
• KT-84058 Lombok. NoSuchMethodError for the builder function when @Builder is applied to the method
• KT-81622 Support @Slf4j and other logging annotations (@CommonsLog, @Flogger, @JBossLog, @Log4j, @Log4j2, @XSlf4j)
• KT-86170 PowerAssert: Stabilize runtime ABI for initial release
• KT-86058 Check the frontend-owned plugins for the Companion blocks and extensions
• KT-85762 Support for @ToString annotation on kotlin classes
• KT-86065 Scripting plugin adds HashMap<K, V> (with HashMap's own out-of-scope type parameters) as a supertype of the synthetic REPL state class
• KT-86064 Plugin sandbox generates IrClassReferenceImpl typed as KClass<T> where T is KClass's own type parameter
• KT-86063 PowerAssert plugin generates IR call to listOf<T> with an out-of-scope type parameter as its type
• KT-86070 PowerAssert: Enum entries should not be displayed
• KT-85250 PowerAssert: Automatically add runtime library dependency
• KT-85472 Compiler crash if use unexpected value of AccessLevel in a lombok annotation
• KT-85693 Don't generate declarations with NONE access level

Tools. Compiler plugins. Serialization

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

Tools. Daemon

• KT-85634 -Xwarning-level warnings are escalated to errors when -Werror is enabled in BTA daemon mode
• KT-71048 KotlinCompileDaemon compatibility not discriminated by JVM version
• KT-75840 Almost dead daemons are considered in the daemon elections

Tools. Gradle

New Features

• KT-78214 Gradle: implement Kotlin/JS compilation and linking through BTA
• KT-80509 Gradle: implement metadata compilation through BTA
• KT-78216 Gradle: implement Kotlin/Wasm compilation and linking through BTA

Fixes

• KT-83679 Add ERROR deprecation for CleanableStore and CleanDataTask
• KT-85689 Delete prepareDeps from kotlin repo
• KT-86118 CRI: Enabling kotlin.compiler.generateCompilerRefIndex does not invalidate compileKotlin UP-TO-DATE state
• KT-85942 Carry compiler diagnostic identifiers through MessageCollector infrastructure
• KT-85568 Use compiler diagnostic identifiers in KGP Problems API reporting
• KT-86346 Compiler warnings printed twice in console — once as w: and again as Gradle "Problem found:" block
• KT-85567 Carry compiler diagnostic identifiers through Build Tools API messages
• KT-85901 [Gradle] Refactor KGP functional test task configuration to use file-backed system properties
• KT-85373 Compile against Gradle API 9.5.0
• KT-85374 Run tests against Gradle 9.5.0
• KT-86429 Deprecate KGP contentEquals() utility, move it to internal utility function
• KT-66381 Build reports in JSON: incorrect path to a json build report is printed to build output if a relative path defined as a value for kotlin.build.report.json.directory property
• KT-85590 Gradle: cannot create task MainKt.main() due to missing defaultSourceSetName
• KT-85412 Module name is not sanitized with older Kotlin compiler versions

Tools. Gradle. Compiler plugins

• KT-84811 PowerAssert: Gradle configuration option for default sourcesets to transform

Tools. Gradle. JS

• KT-86630 Introduce mocha browser runner for kotlin test as part of kotlin-web-helpers
• KT-86260 Integrate Playwright with JS Tests pipeline
• KT-86106 Fix task dependency in KGP lockfile generation
• KT-86271 [WasmJs/Js] 2.4.0-Beta2 - Node version not compatible with popular JS dependencies
• KT-85854 Improve AbstractSetupTask logging
• KT-64275 Gradle: remove deprecated symbols related to the legacy JS target
• KT-84790 Use package.json as 'source of truth' for KGP npm tooling dependencies

Tools. Gradle. Multiplatform

• KT-69571 compileNativeMainKotlinMetadata not handling project/prebuilt substitutions
• KT-84533 KMP: compileCommonMainKotlinMetadata: "Unresolved reference" for androidx.savedstate from Maven (works with project() dependency)
• KT-84767 K/N: associateWith triggers warning about friend-modules libs not included in -library argument
• KT-81117 With android.builtInKotlin=true (AGP 9.0), using kotlin-multiplatform plugin will fail with Cannot add extension with name 'kotlin'
• KT-83370 Incorrect metadata transformation for stdlib's webMain source set
• KT-84669 SPM import: If iosApp dir located outside of the project, checkSyntheticImportProjectIsCorrectlyIntegrated will fail

Tools. Gradle. Native

New Features

• KT-86047 Suggest CocoaPods -> SwiftPM migration skill and documentation on cocoapods plugin application
• KT-86155 Print what changed in the linkage package
• KT-85797 Use faster findMacros in SwiftPM import cinterops
• KT-83873 Redo how dynamic library linkage and promotion are handled

Fixes

• KT-85961 integrateLinkagePackage without parameters fails with an obscure error
• KT-84238 SPM Import: Ensure generated Package.swift preserves symlinks in local package paths
• KT-86015 Swift export binary doesn't see main compilation cinterop output
• KT-85502 Swift PM Import: "Library not loaded": KotlinMultiplatformLinkedPackage.framework is not copied next to the executable
• 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:
• KT-69896 Native: output to stderr ends up in the Gradle log
• KT-85708 [KGP] dSYM copy task ignores isStatic due to eager read before framework configuration
• KT-84262 integrateEmbedAndSign produces an incorrect Gradle call for the root project
• KT-84730 Add Kdocs to SwiftPM import APIs

Tools. Gradle. Wasm

• KT-86457 [Wasm, Gradle] BinaryenExec.standardOutput is silently ignored after migration to Gradle Workers
• KT-85688 K/Wasm: Remove setting of failOnNoDiscoveredTests in Wasm Gradle tests
• KT-86054 K/Wasm: Not set sourceMapBaseDir if there is no sourceMap property in JS and Wasm
• KT-85974 K/Wasm: Do not set -Xir-per-module for Wasm tasks
• KT-85861 K/Wasm: Upgrade NPM dependencies
• KT-85806 K/Wasm: Do not rewrite native_implementations.kt file path in source map

Tools. Incremental Compile

• KT-84271 Kotlin Incremental compilation failure "The following FqNames can't be derived from DirtyData.dirtyLookupSymbols"
• KT-85740 Incremental compilation misses classpath removal when removed type is used only in a dependency's method signature
• KT-85074 IC: false build success when anonymous class fails to implement new abstract member from another module's interface
• KT-85642 IC: Classpath snapshot cache may serve stale entries when snapshot file is overwritten at the same path

Tools. Kapt

• KT-85195 KAPT: IntroducedAt is not supported in KAPT
• KT-86003 Remove MessageCollector usage from kapt
• KT-85453 Make :kotlin-annotation-processing-cli:test cacheable

Tools. Maven

• KT-85622 [Maven] setting kotlin.compiler.jdkRelease without explicit jvmTarget causes compilation failure due to conflicting default
• KT-61667 Maven: -Xjdk-release=20 leads to "'-Xjdk-release=20' option conflicts with '-jvm-target 1.8'. Please remove the '-jvm-target' option"
• KT-84163 Maven smart defaults: and overrides not respected

Tools. Performance benchmarks

• KT-85233 Refine benchmarks module and add new custom long-running tests to it

Tools. REPL

• KT-86290 Drop GenericReplTest & LegacyReplTest

Tools. Scripts

• KT-86391 Drop SkipStandaloneScriptsInSourceRoots

Tools. Wasm

• KT-83434 K/Wasm: add wasm-wasi stdlib into compiler distribution (dist/)