Contents

The release contents the JVM version of the Kotlin compiler, and also the Kotlin/Native compiler for the supported platforms: Linux, macOS and Windows.

Changelog

Compiler

New Features

• KT-23575 Deprecate with replacement and SinceKotlin
• KT-38652 Do not generate optional annotations to class files on JVM
• KT-38777 Hide Throwable.addSuppressed member and prefer extension instead

Performance Improvements

• KT-38489 Compilation of kotlin html DSL increasingly slow
• KT-28650 Type inference for argument type is very slow if several interfaces with a type parameter is used as an upper bound of a type parameter

Fixes

• KT-15971 Incorrect bytecode generated when inheriting default arguments not from the first supertype
• KT-25290 NI: "AssertionError: If original type is SAM type, then candidate should have same type constructor" on out projection of Java class
• KT-28672 Contracts on calls with implicit receivers
• KT-30279 Support non-reified type parameters in typeOf
• KT-31908 NI: CCE on passing lambda to function which accepts vararg SAM interface
• KT-32156 New inference issue with generics
• KT-32229 New inference algorithm not taking into account the upper bound class
• KT-33455 Override equals/hashCode in functional interface wrappers
• KT-34902 AnalyzerException: Argument 1: expected I, but found R for unsigned types in generic data class
• KT-35075 AssertionError: "No resolved call for ..." with conditional function references
• KT-35468 Overcome ambiguity between typealias kotlin.Throws and the aliased type kotlin.jvm.Throws
• KT-35494 NI: Multiple duplicate error diagnostics (in IDE popup) with NULL_FOR_NONNULL_TYPE
• KT-35681 Wrong common supertype between raw and integer literal type leads to unsound code
• KT-35937 Error "Declaration has several compatible actuals" on incremental build
• KT-36013 Functional interface conversion not happens on a value of functional type with smart cast to a relevant functional type
• KT-36045 Do not depend on the order of lambda arguments to coerce result to Unit
• KT-36448 NI: fix tests after enabling NI in the compiler
• KT-36706 Prohibit functional interface constructor references
• KT-36969 Generate @NotNull on instance parameters of Interface$DefaultImpls methods
• KT-37058 Incorrect overload resolution ambiguity on callable reference in a conditional expression with new inference
• KT-37120 [FIR] False UNRESOLVED_REFERENCE for public and protected member functions and properties which are declared in object inner class
• KT-37149 Conversion when generic specified by type argument of SAM type
• KT-37249 false TYPE_MISMATCH when When-expression branches have try-catch blocks
• KT-37341 NI: Type mismatch with combination of lambda and function reference
• KT-37436 AME: "Receiver class does not define or inherit an implementation of the resolved method" in runtime on usage of non-abstract method of fun interface
• KT-37510 NI infers java.lang.Void from the expression in a lazy property delegate and throws ClassCastException at runtime
• KT-37541 SAM conversion with fun interface without a function fails on compiling and IDE analysis in SamAdapterFunctionsScope.getSamConstructor()
• KT-37574 NI: Type mismatch with Kotlin object extending functional type passed as @FunctionalInterface to Java
• KT-37630 NI: ILT suitability in a call is broken if there are CST calculation and calling function's type parameters
• KT-37665 NI: applicability error due to implicitly inferred Nothing for returning T with expected type
• KT-37712 No extension receiver in functional interface created with lambda
• KT-37715 NI: VerifyError: Bad type on operand stack with varargs generic value when type is inferred
• KT-37721 NI: Function reference with vararg parameter treated as array and missing default parameter is rejected
• KT-37887 NI: Smart casting for Map doesn't work if the variable is already "smart casted"
• KT-37914 NI: broken inference for a casting to subtype function within the common constraint system with this subtype
• KT-37952 NI: improve lambdas completion through separation the lambdas analysis into several steps
• KT-38069 Callable reference adaptation should have dependency on API version 1.4
• KT-38143 New type inference fails when calling extension function defined on generic type with type arguments nested too deep
• KT-38156 FIR Metadata generation
• KT-38197 java.lang.OutOfMemoryError: Java heap space: failed reallocation of scalar replaced objects
• KT-38259 NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER for provideDelegate
• KT-38337 Map delegation fails for inline classes
• KT-38401 FIR: protected effective visibility is handled unprecisely
• KT-38416 FIR: infinite loop in BB coroutine test 'overrideDefaultArgument.kt'
• KT-38432 FIR: incorrect effective visibility in anonymous object
• KT-38434 Implement resolution of suspend-conversion on FE only, but give error if suspend conversion is called
• KT-38437 [FIR] String(CharArray) is resolved to java.lang.String constructor instead of kotlin.text.String pseudo-constructor
• KT-38439 NI: anonymous functions without receiver is allowed if there is an expected type with receiver
• KT-38473 FIR: ConeIntegerLiteralType in signature
• KT-38537 IllegalArgumentException: "marginPrefix must be non-blank string" with raw strings and space as margin prefix in trimMargin() call
• KT-38604 Implicit suspend conversion on call arguments doesn't work on vararg elements
• KT-38680 NSME when calling generic interface method with default parameters overriden with inline class type argument
• KT-38681 Wrong bytecode generated when calling generic interface method with default parameters overriden with primitive type argument
• KT-38691 NI: overload resolution ambiguity if take R and () -> R, and pass literal lambda, which returns R
• KT-38799 False positive USELESS_CAST for lambda parameter
• KT-38802 Generated code crashes by ClassCastException when delegating with inline class
• KT-38853 Backend Internal error: Error type encountered: Unresolved type for nested class used in an annotation argument on an interface method
• KT-38890 NI: false negative Type mismatch for values with fun keyword
• KT-39010 NI: Regression with false-positive smartcast on var of generic type
• KT-39013 202, ASM 8: "AnalyzerException: Execution can fall off the end of the code"
• KT-39260 "AssertionError: Unsigned type expected: Int" in range
• KT-39305 NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER: unable to infer deeply nested type bound when class implements generic interface
• KT-39408 Using unsigned arrays as generics fails in 1.4-M2 with class cast exception
• KT-39533 NI: Wrong overload resolution for methods with SAM converted function reference arguments
• KT-39535 NI: Inference fails for the parameters of SAM converted lambdas with type parameters
• KT-39603 Require explicit override in JVM default compatibility mode on implicit generic specialization of inherited methods in classes
• KT-39671 Couldn't inline method call 'expectBody'
• KT-39816 NI:ClassCastException and no IDE error with provideDelegate when DELEGATE_SPECIAL_FUNCTION_MISSING in OI
• KT-32779 Rewrite at slice in array access resolution in coroutine inference
• KT-39387 Can't build Kotlin project due to overload resolution ambiguity on flatMap calls
• KT-39229 NI: resolution to wrong candidate (SAM-type against similar functional type)

Docs & Examples

• KT-36245 Document that @kotlin.native.ThreadLocal annotation doesn't work anywhere except in Kotlin/Native
• KT-37943 Conflicting overloads in the factory functions sample code in Coding Conventions Page

IDE

New Features

• KT-10974 Add Code Style: Import Layout Configuration Table
• KT-39065 "Join lines" should remove trailing comma on call site

Fixes

• KT-9065 Wrong result when move statement through if block with call with lambda
• KT-14757 Move statement up breaks code in function parameter list
• KT-14946 Move statement up/down (with Ctrl+Shift+Up/Down) messes with empty lines
• KT-15143 Kotlin: Colors&Fonts -> "Enum entry" should use Language Default -> Classes - Static field
• KT-17887 Moving statement (Ctrl/Cmd+Shift+Down) messes with use block
• KT-34187 UAST cannot get type of array access
• KT-34524 "PSI and index do not match" and IDE freeze with library import from square/workflow
• KT-35574 UAST: UBreakExpression in when expression should be UYieldExpression
• KT-36801 IDE: Unsupported language version value is represented with "latest stable" in GUI
• KT-37378 Remove IDE option "Enable new type inference algorithm..." in 1.4
• KT-38003 "Analyze Data Flow from Here" should work on parameter of abstract method
• KT-38173 Reified types do no have extends information
• KT-38217 Make Kotlin plugin settings searchable
• KT-38247 "IncorrectOperationException: Incorrect expression" through UltraLightUtils.kt: inlined string is not escaped before parsing
• KT-38293 Throwable: "'codestyle.name.kotlin' is not found in java.util.PropertyResourceBundle" at KotlinLanguageCodeStyleSettingsProvider.getConfigurableDisplayName()
• KT-38407 Drop components from plugin.xml
• KT-38443 No error on change in property initializer
• KT-38521 ISE: Loop in parent structure when converting a DOT_QUALIFIED_EXPRESSION with parent ANNOTATED_EXPRESSION
• KT-38571 Rework deprecated EPs
• KT-38632 Change the code style to official in tests

IDE. Code Style, Formatting

Fixes

• KT-24750 Formatter: Minimum blank lines after class header does nothing
• KT-31169 IDEA settings search fails to find "Tabs and Indents" tab in Kotlin code style settings
• KT-35359 Incorrect indent for multiline expression in string template
• KT-37420 Add setting to disable inserting empty line between declaration and declaration with comment
• KT-37891 Formatter inserts empty lines between annotated properties
• KT-38036 Use trailing comma setting does not apply to code example in Settings dialog
• KT-38568 False positive: weak warning "Missing line break" on -> in when expression
• KT-39024 Add option for blank lines before declaration with comment or annotation on separate line
• KT-39079 Trailing comma: add base support for call site
• KT-39123 Option Align 'when' branches in columns does nothing
• KT-39180 Move trailing comma settings in Other tab

IDE. Completion

• KT-18538 Completion of static members of grand-super java class inserts unnecessary qualifier
• KT-38445 Fully qualified class name is used instead after insertion of delay method

IDE. Debugger

Fixes

• KT-14057 Debugger couldn't step into Reader.read
• KT-14828 Bad step into/over behavior for functions with default parameters
• KT-36403 Method breakpoints don't work for libraries
• KT-36404 Evaluate: "AssertionError: Argument expression is not saved for a SAM constructor"
• KT-37486 Kotlin plugin keeps reference to stream debugger support classes after stream debugger plugin is disabled
• KT-38484 Coroutines Debugger: IAE “Requested element count -1 is less than zero.” is thrown by calling dumpCoroutines
• KT-38606 Coroutine Debugger: OCE from org.jetbrains.kotlin.idea.debugger.coroutine.proxy.mirror.BaseMirror.isCompatible
• KT-39143 NPE on setCurrentStackFrame to Kotlin inner compiled class content
• KT-39412 Failed to find Premain-Class manifest attribute when debugging main method with ktor
• KT-39634 (CoroutineDebugger) Agent doesn't start if using kotlinx-coroutines-core only dependency
• KT-39648 Coroutines debugger doesn't see stacktraces in case of the project has kotlinx-coroutines-debug dependency

IDE. Gradle Integration

Performance Improvements

• KT-39059 Poor performance of modifyDependenciesOnMppModules

Fixes

• KT-35921 Gradle Import fails with "Unsupported major.minor version 52.0" on pure Java project in case "Gradle JDK" is lower 1.8 and Kotlin plugin is enabled
• KT-36673 Gradle Project importing: move ModelBuilders and ModelProviders to kotlin-gradle-tooling jar
• KT-36792 IDEA 2020.1: Some module->module dependencies in HMPP project are missed after import from Gradle
• KT-37125 Imported modules structure for MPP project is displayed messy in UI in IDEA 2020.1
• KT-37428 NPE at KotlinFacetSettings.setLanguageLevel() on the first project import
• KT-38706 IDE Gradle import creates 4 JavaScript modules for MPP source sets with BOTH compiler type
• KT-38767 Published hierarchical multiplatform library symbols are unresolved in IDE (master)
• KT-38842 False positive [INVISIBLE_MEMBER] for internal declaration of commonMain called from commonTest
• KT-39213 IDE: references from MPP project to JavaScript library are unresolved, when project and library are compiled with "both" mode
• KT-39657 Language settings for intermediate source-sets are lost during import

IDE. Gradle. Script

New Features

• KT-34481 *.gradle.kts: use Intellij IDEA Gradle project sync mechanics for updating script configuration

Performance Improvements

• KT-34138 Deadlock in ScriptTemplatesFromDependenciesProvider
• KT-38875 Deadlock in ScriptClassRootsUpdater.checkInvalidSdks

Fixes

• KT-34265 Bogus "build configuration failed, run 'gradle tasks' for more information" message and other issues related to "script dependencies"
• KT-34444 *.gradle.kts: special storage of all scripts configuration on one file
• KT-35153 build.gradle.kts: scripts in removed subproject remain imported, but shouldn't
• KT-35573 Request for gradle build script configuration only after explicit click on notification
• KT-36675 move .gradle.kts ModelBuilders and ModelProviders to kotlin-gradle-tooling jar
• KT-37178 build.gradle.kts: Rework the notification for scripts out of project
• KT-37631 Unnecessary loading dependencies after opening build.gradle.kts after project import with Gradle 6
• KT-37863 Scanning dependencies for script definitions takes too long or indefinitely during Gradle import
• KT-38296 MISSING_DEPENDENCY_SUPERCLASS in the build.gradle.kts editor while Gradle runs Ok
• KT-38541 "Invalid file" exception in ScriptChangeListener.getAnalyzableKtFileForScript()
• KT-39104 “Gradle Kotlin DSL script configuration is missing” after importing project in IJ201, Gradle 6.3
• KT-39469 Gradle version is not updated in script dependencies if the version of gradle was changed in gradle-wrapper.properties
• KT-39771 Freeze 30s from org.jetbrains.kotlin.scripting.resolve.ApiChangeDependencyResolverWrapper.resolve on loading script configuration with Gradle 5.6.4

IDE. Inspections and Intentions

New Features

• KT-14884 Intention to add missing "class" keyword for enum and annotation top-level declarations
• KT-17209 Provide intention to fix platform declaration clash (CONFLICTING_JVM_DECLARATIONS)
• KT-24522 Suggest to move typealias outside the class
• KT-30263 Detect redundant conversions of unsigned types
• KT-35893 Support Inspection for unnecessary asSequence() call
• KT-38559 "Change JVM name" (@JvmName) quickfix: improve name suggester for generic functions
• KT-38597 Expand Boolean intention
• KT-38982 Add "Logger initialized with foreign class" inspection
• KT-39131 TrailingCommaInspection: should suggest fixes for call-site without warnings

Fixes

• KT-5271 Missing QuickFix for Multiple supertypes available
• KT-11865 "Create secondary constructor" quick fix always inserts parameter-less call to this()
• KT-14021 Quickfix to add parameter to function gives strange name to parameter
• KT-17121 "Implement members" quick fix is not suggested
• KT-17368 Don't highlight members annotated with @JsName as unused
• KT-20795 "replace explicit parameter with it" creates invalid code in case of overload ambiguities
• KT-22014 Intention "convert lambda to reference" should be available for implicit 'this'
• KT-22015 Intention "Convert lambda to reference" should be available in spite of the lambda in or out of parentheses
• KT-22142 Intentions: "Convert to primary constructor" changes semantics for property with custom setter
• KT-22878 Empty argument list at the call site of custom function named "suspend" shouldn't be reported as unnecessary
• KT-24281 Importing of invoke() from the same file is reported as unused even if it isn't
• KT-25050 False-positive inspection "Call replaceable with binary operator" for 'equals'
• KT-26361 @deprecated "ReplaceWith" quickfix inserts 'this' incorrectly when using function imports
• KT-27651 'Condition is always true' inspection should not be triggered when the condition has references to a named constant
• KT-29934 False negative Change type quickfix on primary constructor override val parameter when it has wrong type
• KT-31682 'Convert lambda to reference' intention inside class with function which return object produces uncompilable code
• KT-31760 Implement Abstract Function/Property intentions position generated member improperly
• KT-32511 Create class quick fix is not suggested in super type list in case of missing primary constructor
• KT-32565 False positive "Variable is the same as 'credentials' and should be inlined" with object declared and returned from lambda
• KT-32801 False positive "Call on collection type may be reduced" with mapNotNull, generic lambda block and new inference
• KT-33951 ReplaceWith quickfix with unqualified object member call doesn't substitute argument for parameter
• KT-34378 "Convert lambda to reference" refactoring does not work for suspend functions
• KT-34677 False positive "Collection count can be converted to size" with Iterable
• KT-34696 Wrong 'Redundant qualifier name' for 'MyEnum.values' usage
• KT-34713 "Condition is always 'false'": quickfix "Delete expression" doesn't remove else keyword (may break control flow)
• KT-35015 ReplaceWith doesn't substitute parameters with argument expressions
• KT-35329 Replace 'when' with 'if' intention: do not suggest if 'when' is used as expression and it has no 'else' branch
• KT-36194 "Add braces to 'for' statement" inserts extra line break and moves the following single-line comment
• KT-36406 "To ordinary string literal" intention adds unnecessary escapes to characters in template expression
• KT-36461 "Create enum constant" quick fix adds after semicolon, if the last entry has a comma
• KT-36462 "Create enum constant" quick fix doesn't add trailing comma
• KT-36508 False positive "Replace 'to' with infix form" when 'to' lambda generic type argument is specified explicitly
• KT-36930 Intention "Specify type explicitly" adds NotNull annotation when calling java method with the annotation
• KT-37148 "Remove redundant .let call doesn't remove extra calls
• KT-37156 "Unused unary operator" inspection highlighting is hard to see
• KT-37173 "Replace with string templates" intention for String.format produces uncompilable string template
• KT-37181 Don't show "Remove redundant qualifier name" inspection on qualified Companion imported with star import
• KT-37214 "Convert lambda to reference" with a labeled "this" receiver fails
• KT-37256 False positive PlatformExtensionReceiverOfInline inspection if a platform type value is passed to a nullable receiver
• KT-37744 "Convert lambda to reference" inspection quick fix create incompilable code when type is inferred from lambda parameter
• KT-37746 "Redundant suspend modifier" should not be reported for functions with actual keyword
• KT-37842 "Convert to anonymous function" creates broken code with suspend functions
• KT-37908 "Convert to anonymous object" quickfix: false negative when interface has concrete functions
• KT-37967 Replace 'invoke' with direct call intention adds unnecessary parenthesis
• KT-37977 "Replace 'invoke' with direct call" intention: false positive when function is not operator
• KT-38062 Reactor Quickfix throws NotImplementedError for Kotlin
• KT-38240 False positive redundant semicolon with as cast and not unary operator on next line
• KT-38261 Redundant 'let' call removal leaves ?. operator and makes code uncompilable
• KT-38310 Remove explicit type annotation intention drops 'suspend'
• KT-38492 False positive "Add import" intention for already imported class
• KT-38520 SetterBackingFieldAssignmentInspection throws exception
• KT-38649 False positive quickfix "Assignment should be lifted out of when" in presence of smartcasts
• KT-38677 Invalid psi tree after Lift assigment out of...
• KT-38790 "Convert sealed subclass to object" for data classes doesn't remove 'data' keyword
• KT-38829 'Remove redundant backticks' can be broken with @ in name
• KT-38831 'Replace with assignment' can be broken with fast code change
• KT-38832 "Remove curly braces" intention may produce CCE
• KT-38948 False positive quickfix "Make containing function suspend" for anonymous function
• KT-38961 "Useless call on collection type" for filterNotNull on non-null array where list return type is expected
• KT-39069 Improve TrailingCommaInspection
• KT-39151 False positive inspection to replace Java forEach with Kotlin forEach when using ConcurrentHashMap

IDE. JS

• KT-39275 Kotlin JS Browser template for kotlin dsl doesn't include index.html

IDE. KDoc

• KT-32163 Open Quick Documentation when cursor inside function / constructor brackets

IDE. Navigation

• KT-32245 Method in Kotlin class is not listed among implementing methods
• KT-33510 There is no gutter icon to navigate from actual to expect if expect and the corresponding actual declarations are in the same file
• KT-38260 Navigation bar doesn't show directories of files with a single top level Kotlin class
• KT-38466 Top level functions/properties aren't shown in navigation panel

IDE. Project View

• KT-36444 Structure view: add ability to sort by visibility
• KT-38276 Structure view: support visibility filter for class properties

IDE. REPL

• KT-38454 Kotlin REPL in IntelliJ doesn't take module's JVM target setting into account

IDE. Refactorings

• KT-12878 "Change signature" forces line breaks after every parameter declaration
• KT-30128 Change Signature should move lambda outside of parentheses if the arguments are reordered so that the lambda goes last
• KT-35338 Move/rename refactorings mess up code formatting by wrapping lines
• KT-38449 Extract variable refactoring is broken by NPE
• KT-38543 Copy can't work to package with escaped package
• KT-38627 Rename package refactorings mess up code formatting by wrapping lines

IDE. Run Configurations

• KT-34516 Don't suggest incompatible targets in a drop-down list for run test gutter icon in multiplatform projects
• KT-38102 DeprecatedMethodException ConfigurationFactory.getId

IDE. Scratch

• KT-38455 Kotlin scratch files don't take module's JVM target setting into account

IDE. Script

• KT-39791 Kotlin plugin loads VFS in the output directories

IDE. Structural Search

• KT-39721 Optimize Kotlin SSR by using the index
• KT-39733 Augmented assignment matching
• KT-39769 "When expressions" predefined template doesn't match all when expressions

IDE. Wizards

• KT-38673 New Project Wizard: multiplatform templates are generated having unsupported Gradle version in a wrapper
• KT-38810 Incorrect order of build phases in Xcode project from new wizard
• KT-38952 Remove old new_project_wizards
• KT-39503 New Project wizard 1.4+: release kotlinx.html version is added to dependencies with milestone IDE plugin
• KT-39700 Wizard: group project templates on the first step by the project type
• KT-39770 CSS Support in Kotlin wizards
• KT-39826 Fix Android app in New Template Wizard
• KT-39843 Change imports in JS/browser wizard

JS. Tools

• KT-32273 Kotlin/JS console error on hot reload
• KT-39498 Update dukat version in toolchain near to release of 1.4-M3

JavaScript

• KT-29916 Implement typeOf on JS
• KT-35857 Kotlin/JS CLI bundled to IDEA plugin can't compile using IR back-end out of the box
• KT-36798 KJS: prohibit using @JsExport on a non-top-level declaration
• KT-37771 KJS: Generated TypeScript does not recursively export base classes (can fail with generics)
• KT-38113 Review public API of JS stdlib for IR BE
• KT-38765 [JS / IR] AssertionError: class EventEmitter: Super class should be any: with nested class extending parent class
• KT-38768 KJS IR: generate ES2015 (aka ES6) classes

Libraries

New Features

• KT-11253 Function to sum long or other numeric property of items in a collection
• KT-28933 capitalize() with Locale argument in the JDK stdlib
• KT-34142 Create SortedMap with Comparator and items
• KT-34506 Add Sequence.flatMap overload that works on Iterable
• KT-36894 Support flatMapIndexed in the Collections API
• KT-38480 Introduce experimental annotation for enabling overload resolution by lambda result
• KT-38708 minOf/maxOf functions to return min/max value provided by selector
• KT-39707 Make some interfaces in stdlib functional

Performance Improvements

• KT-23142 toHashSet is suboptimal for inputs with a lot of duplicates

Fixes

• KT-21266 Add module-info for standard library artifacts
• KT-23322 Document 'reduce' operation behavior on empty collections
• KT-28753 Comparing floating point values in array/list operations 'contains', 'indexOf', 'lastIndexOf': IEEE 754 or total order
• KT-30083 Annotate KTypeProjection.STAR with JvmField in a compatible way
• KT-30084 Annotate functions in KTypeProjection.Companion with JvmStatic
• KT-31343 Deprecate old String <-> CharArray, ByteArray conversion api
• KT-34596 Add some validation to KTypeProjection constructor
• KT-35978 Review and remove experimental stdlib API status for 1.4
• KT-38388 Document fromIndex and toIndex parameters
• KT-38854 Gradually change the return type of collection min/max functions to non-nullable
• KT-39023 Document split(Pattern) extension differences from Pattern.split
• KT-39064 Introduce minOrNull and maxOrNull extension functions on collections
• KT-39235 Lift experimental annotation from bit operations
• KT-39237 Lift experimental annotation from common StringBuilder
• KT-39238 Appendable.appendRange - remove nullability
• KT-39239 Lift experimental annotation from String <-> utf8 conversion api
• KT-39244 KJS: update polyfills, all or most of them must not be enumerable
• KT-39330 Migrate declarations from kotlin.dom and kotlin.browser packages to kotlinx.*

Middle-end. IR

• KT-31088 need a way to compute fake overrides for pure IR
• KT-33207 Kotlin/Native: KNPE during deserialization of an inner class
• KT-33267 Kotlin/Native: Deserialization error for an "inner" extension property imported from a class
• KT-37255 Make psi2ir aware of declarations provided by compiler plugins

Reflection

• KT-22936 Not all things can be changed to createType yet, and now defaultType methods are starting to fail
• KT-32241 Move KType.javaType into stdlib from reflect
• KT-34344 KType.javaType implementation throws when invoked with a typeOf()
• KT-38491 IllegalArgumentException when using callBy on function with inline class parameters and default arguments
• KT-38881 Add KClass.isFun modifier of functional interfaces to reflection

Tools. Android Extensions

• KT-25807 Kotlin extension annotation @parcelize in AIDL returns Object instead of original T

Tools. CLI

• KT-30211 Support a way to pass arguments to the underlying JVM in kotlinc batch scripts on Windows
• KT-30778 kotlin-compiler.jar contains shaded but not relocated kotlinx.coroutines
• KT-38070 Compiler option to bypass prerelease metadata incompatibility error
• KT-38413 Add JVM target bytecode version 14

Tools. Compiler Plugins

• KT-39274 [KJS / IR] Custom serializer for class without zero argument constructor doesn't compile

Tools. Gradle

• KT-25428 Kotlin Gradle Plugin: Use new Gradle API for Lazy tasks
• KT-34487 Gradle build fails with "Cannot run program "java": error=7, Argument list too long
• KT-35957 MPP IC fails with "X has several compatible actual declarations" error
• KT-38250 Drop support for Gradle versions older than 5.3 in the Kotlin Gradle plugin

Tools. Gradle. JS

New Features

• KT-30619 Support NPM transitive dependencies in multi-platform JS target
• KT-38286 [Gradle, JS] Error handling on Webpack problems

Fixes

• KT-31669 Gradle/JS: rise error when plugin loaded more than once
• KT-32531 [Gradle/JS] Add scoped NPM dependencies
• KT-34832 [Kotlin/JS] Failed build after webpack run (Karma not found)
• KT-35194 Kotlin/JS: browserRun fails with "address already in use" when trying to connect to local server
• KT-35611 Kotlin Gradle plugin should report kotlin2js plugin ID as deprecated
• KT-35641 Kotlin Gradle plugin should report kotlin-dce-js plugin ID as deprecated
• KT-36410 JS: Collect stats about IR backend usage
• KT-36451 KJS Adding npm dependency breaks Webpack devserver reloading
• KT-37258 Kotlin/JS + Gradle: in continuous mode kotlinNpmInstall time to time outputs "ENOENT: no such file or directory" error
• KT-38109 [Gradle, JS] Error handling on Karma launcher problems
• KT-38331 Add an ability to control generating externals for npm deps individually
• KT-38485 [Gradle, JS] Unable to configure JS compiler with string
• KT-38683 Remove possibility to set NPM dependency without version
• KT-38990 Support multiple range versions for NPM dependencies
• KT-38994 Remove possibility to set NPM dependency with npm(org, name, version)
• KT-39109 ArithmeticException: "/ by zero" caused by kotlinNodeJsSetup task with enabled gradle caching on Windows
• KT-39210 Kotlin/JS: with both JS and MPP modules in the same project Gradle configuration fails on nodejs {} and browser {}
• KT-39377 Use standard source-map-loader instead of custom one

Tools. Gradle. Multiplatform

• KT-39184 Support publication of Kotlin-distributed libraries with Gradle Metadata
• KT-39304 Gradle import error java.util.NoSuchElementException: Key source set foo is missing in the map on unused source set

Tools. Gradle. Native

• KT-37514 CocoaPods Gradle plugin: Support building from terminal projects for several platforms
• KT-38440 Make error message about missing Podfile path for cocoapods integration actionable for a user
• KT-38991 Gradle MPP plugin: Enable parallel in-process execution for K/N compiler
• KT-39935 Support overriding the KotlinNativeCompile task sources
• KT-37512 Cocoapods Gradle plugin: Improve error logging for external tools

Tools. J2K

• KT-35169 Do not show "Inline local variable" popup during "Cleaning up code" phase of J2K
• KT-38004 J2K breaks java getter call in java code
• KT-38450 J2K should convert Java SAM interfaces to Kotlin fun interfaces

Tools. JPS

• KT-27458 The Kotlin standard library is not found in the module graph ... in a non-Kotlin project.
• KT-29552 Project is completely rebuilt after each gradle sync.

Tools. Scripts

• KT-37766 Impossible to apply compiler plugins onto scripts with the new scripting API

Tools. kapt

• KT-29355 Provide access to default values for primary constructor properties