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Kotlin v1.4.0 released!

Kotlin v1.4.0 has been released.

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

1.4.0

Compiler

New Features

KT-23729 Provide a way to generate JVM default method bodies in interfaces delegating to DefaultImpls

KT-30330 Introduce KotlinNothingValueException and throw it instead of NPE on expressions of type Nothing

KT-38435 Support suspend conversion on callable references in JVM backend

Fixes

KT-35483 NI: compatibility mode

KT-39728 Declarations from kotlin.reflect resolved to expect-classes even in JVM modules in IDE

KT-40153 REPL IDE services completion fails on imports completion

KT-40404 Mixed named/positional arguments: argument can be passed twice

KT-40544 NI: “TYPE_MISMATCH: Required: MutableList<out T!> Found: List” caused by Java interface function

KT-40555 NI: Spread operator allows inferred nullable types

KT-40646 NI: TYPE_MISMATCH: “inferred type is Unit but Observer was expected” caused by LieData.observe inference

KT-40691 False positive CAPTURED_VAL_INITIALIZATION with EXACTLY_ONCE contract

KT-40693 UnsupportedOperationException: no descriptor for type constructor of (CapturedType(out TResult)…CapturedType(out TResult)?)

KT-40824 Usages of a typealias lose nullability and annotations in deserialization

KT-40843 Unhandled exception for suspending methods that return Result type

KT-40869 Recursion computation inside compiler resolve on a correct code

KT-40893 Error “Captured values initialization is forbidden due to possible reassignment” when attempting to use the plusAssign operator with a java list inside an inline function

KT-40919 kotlin.collections.ArrayDeque requires an explicit import when compiling with kotlinc 1.4-RC and -language-version 1.3

KT-40920 Regression in JvmDefault: incorrect access to missing DefaultImpls on default methods in Java interface overriding Kotlin interface

KT-40978 Prohibit using suspend functions as SAM in fun interfaces

Kotlin/Native

Objective-C/Swift interop:

Reworked exception handling (GH-3822, GH-3842)

Enabled support for Objective-C generics by default (GH-3778)

Support for Kotlin’s suspending functions (GH-3915)

Handle variadic block types in ObjC interop (KT-36766)

Added native-specific frontend checkers (implemented in the main Kotlin repository: GH-3293, GH-3091, GH-3172)

.dSYMs for release binaries on Apple platforms (GH-4085)

Improved compilation time of builds with interop libraries by reworking cinterop under the hood.

Experimental mimalloc allocator support (-Xallocator=mimalloc) to improve execution time performance. (GH-3704)

Tune GC to improve execution time performance

Various fixes to compiler caches and Gradle daemon usage

Docs & Examples

KT-35218 Fix misleading in JavaDoc for createTempDir/createTempFile

KT-36981 Provide a visual illustration of source sets structure generated by ios(), watchos(), tvos() presets

KT-38050 Language Guide: MPP reference: add sample of language settings for all roots instead of common root only

IDE

KT-30265 IDE, MPP: False negative TYPE_PARAMETER_AS_REIFIED in common code

KT-40494 UAST: “NoSuchElementException: No element of given type found” with use-site target annotation

KT-40639 Shift IDE plugins updater numbers for Kotlin plugin

IDE. Code Style, Formatting

KT-40636 Hard freeze on formatter: infinite recursion

IDE. Gradle Integration

KT-30116 IDE: Unresolved reference in MPP module (androidMain source set) for annotation from common module (defined in commonMain and with JVM target)

IDE. Gradle. Script

KT-34552 Deadlock in ScriptDefinitionsManager

KT-40675 Gradle build file is not highlighted until navigating to symbol

IDE. JS

KT-40461 Create new projects with kotlin.js.generate.executable.default=false

IDE. Script

KT-39547 Kotlin script support freezes IDEA

KT-40242 gradle.kts: Deadlock in ScriptClassRootsUpdater

IDE. Wizards

KT-36153 New Project Wizard: provide more referential info on project structure editor screen

KT-39904 New Project wizard 1.4: update Frontend Application to make it run with JS IR

KT-40149 Gradle project wizard: templates for Kotlin/JS are not properly formatted

JavaScript

KT-25859 JS: support function references to functions with vararg if expected type ends with repeated vararg element type

KT-40083 K/JS-IR: java.lang.IllegalStateException: has not acquired a symbol yet

KT-40892 KJS, IR: Unresolved references on importing classes from kotlinx-nodejs

Libraries

KT-39051 Libraries native artifacts are published without sources

Tools. Gradle

KT-27816 Provide a possibility to specify intermediate source sets between platform-agnostic and platform-specific test source sets

KT-37720 Replace ArtifactTransform with TransformAction

KT-40559 Adding the stdlib by default triggers warning in the Android Gradle Plugin

Tools. Gradle. JS

KT-40093 Incorrect updating version of Kotlin/JS dependencies in package.json

Tools. Gradle. Multiplatform

KT-27320 Provide a way to reuse same sources for similar Native target

KT-40058 NPE from mpp gradle plugin on kotlinx.benchmarks

Tools. Gradle. Native

KT-40801 Gradle CocoaPods integration: Cannot change a framework name

1.4-RC

Backend. Native

KT-40209 java.lang.UnsupportedOperationException: org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl@76484173

KT-40367 Kotlin/Native-Swift interop (iOS): Array member initialization failing in release builds

Compiler

Fixes

KT-31025 Type mismatch when callable reference is resolved with a functional expected type and SAM conversion

KT-37388 Consider relaxing rules about inferring Nothing inside special constructions (if, try, when)

KT-37717 NI: “IllegalStateException: Error type encountered” with @BuilderInference

KT-38427 New inference in branched conditions (if, when) results in odd behavior with inconsistent compiler warnings and runtime errors

KT-38899 NI: False positive IMPLICIT_NOTHING_TYPE_ARGUMENT_IN_RETURN_POSITION leads to NPE

KT-39468 NI: overload resolution ambiguity between functions passing T and Foo<T> with a contravariant receiver

KT-39618 NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER: unable to infer generic type on @BuilderInference annotated lambda parameter with receiver type

KT-39633 NI: Incorrect type parameter instantiation based on contravariant type argument

KT-39691 NI: Missing SAM conversion for nullable lambda

KT-39860 Make Kotlin binaries publicly available (set KotlinCompilerVersion.IS_PRE_RELEASE = false)

KT-39900 NI: Incorrect type inference in a lambda returning Unit

KT-39925 New JVM default compilation mode doesn’t check that JVM target is 1.8

KT-39943 Write information about all-compatibility mode in metadata

KT-39953 NI: ClassCastException “cannot be cast to java.lang.Void” with if-else in return statement in ANdroid project

KT-40045 NI: lambda’s receiver type isn’t inferred properly

KT-40057 NI: provideDelegate org.jetbrains.kotlin.codegen.CompilationException: Back-end (JVM) Internal error: wrong bytecode generated for static initializer

KT-40060 NI: postponed variable from the builder inference flows to back-end and leads to throw an exception

KT-40112 Kotlin Gradle DSL: COMPATIBILITY_WARNING on kotlin.sourceSets block

KT-40113 Kotlin Gradle DSL: “Expression ‘main’ cannot be invoked as a function” for distributions.main DSL block

KT-40128 Introduce compiler key to disable compatibility resolution mechanism for new inference features

KT-40151 NI: postponed variable isn’t substituted for top-level CR inside builder inference

KT-40214 AbstractMethodError in gradle subplugin which is used in Android app

KT-40234 Deprecation level “hidden” has no effect on callable reference argument

KT-40247 NI: false positive “function should be called from coroutine or another suspend function” for suspend invoke operator in try-catch

KT-40254 Rewrite at slice with two callable reference arguments

KT-40269 NI: “disabled Unit conversions” error has appeared on green code

KT-40337 NI: false positive “function should be called from coroutine or another suspend function” for suspend invoke operator in when block

KT-40406 Prohibit reflection on adapted callable references

IDE

KT-39968 Paths in KotlinJavaRuntime library aren’t updated after you run IDE from a different directory

KT-39989 NullPointerException when opening Kotlin facets in Project Structure dialog in IDEA 192

KT-40311 Create change_notes for 1.4 in IDE plugin description

IDE. Debugger

KT-39808 (CoroutineDebugger) Doesn’t start with kotlinx-coroutines-core >= 1.3.6

KT-40073 (CoroutineDebugger) Change minimum supported kotlinx.coroutines version to 1.3.8*

KT-40172 Restored frame variables isn’t shown for suspended coroutines

KT-40635 Coroutines Debugger: make IDE plugin accept coroutines 1.3.8-rc* versions as well

IDE. Gradle Integration

KT-38744 No dependency between Android test and commonTest source sets with kotlin.mpp.enableGranularSourceSetsMetadata=true

KT-39037 ‘None of the consumable configurations have attributes’ in MPP IDE import with transitive project dependency on self

IDE. Gradle. Script

KT-31137 IntelliJ would get very slow when editing gradle buildSrc(using the kotlin dsl)

KT-36078 Gradle Kotlin script context is not reloaded when gradle/wrapper/gradle-wrapper.properties file is changed

KT-39317 ISE “Calling invokeAndWait from read-action leads to possible deadlock.” on importing simple Gradle-based project in nightly IJ

IDE. Inspections and Intentions

KT-28662 Inspection to flag usage of the wrong Transient annotation on Kotlin Serializable class

KT-34209 Switch default behaviour in 1.4 for insertion (to build script) via quick fix of the compiler option enabling inline classes

KT-36131 Suggest to add a missing module dependency on an unresolved reference in Kotlin code

KT-37462 Add “Add dependency to module” quickfix in multimodule Maven project

KT-39869 Add whole project migration usages of kotlin.browser.* & kotlin.dom.* to kotlinx.browser.* & kotlinx.dom.* respectively

IDE. Wizards

KT-40004 New Project wizard 1.4+: no https://dl.bintray.com/kotlin/kotlinx repository is added for kotlinx-html

KT-40037 New Project wizard: update Ktor version

KT-40092 Wizard: the templates panel on mac OS is too wide

KT-40232 New Wizard: Android Sdk path doesn’t have backslash escaping on Windows

KT-40371 New Project Wizard: Frontend Application / Library results in broken run configuration

KT-40377 New Project Wizard: Frontend Application defines NPM dependencies that are unnecessary with Kotlin 1.4-RC+

KT-40378 New Project Wizard: Frontend Application, Disabling JavaScript test framework has no effect

KT-40407 Wizard: do not add stdlib by default for Gradle projects in wizard

JS. Tools

KT-39984 Update dukat version in toolchain near to release of 1.4-RC

JavaScript

KT-32186 Make sure K/JS Reflection API documentation is correct and fix it.

KT-37563 K/JS: stacktrace is not captured for exceptions without primary constructor inherited from Exception/Error

KT-37752 Generated typescript incorrect for constructors of derived classes

KT-37883 KJS: Generated TypeScript uses ‘declare’ rather than ‘export’

KT-38771 JS: support non-reified type parameters in typeOf

KT-39873 Update Kotlin JavaScript wrappers due to NON_EXPORTABLE_TYPE diagnostic introduction

KT-40126 [JS / IR] NPE while compiling interfaces with invoke which is passed as a delegate

KT-40216 KJS / IR: AssertionError caused by an anonymous object in the dependency project

Libraries

KT-33069 StringBuilder common functions

KT-35972 Add contract to builder functions

KT-37101 Mark following api with DeprecatedSinceKotlin(“1.4”)

KT-38360 Make sure that JB libraries correctly define their npm deps and republish them (after KT-30619)

KT-38817 ‘capitalize’ should convert digraphs to title case

KT-40168 Remove StringBuilder.capacity from common and JS parts

Middle-end. IR

KT-40520 Assert during fake-override generation

Tools. Commonizer

KT-40199 Commonizer loses nullability of abbreviated types

Tools. Compiler Plugins

KT-40036 Add diagnostic that shows is serialization plugin compatible with serialization-runtime

Tools. Gradle

KT-39755 [KJS / Gradle / Legacy mode] Directory with whitespace is not processed

KT-39809 Kotlin Gradle plugin: ServiceConfigurationError: org.jetbrains.kotlin.gradle.plugin.KotlinGradleSubplugin: Provider org.jetbrains.kotlin.gradle.internal.AndroidSubplugin not a subtype

KT-39977 Collect statistics of used -Xjvm-default options

KT-40300 Fail the build if in MPP plugin no targets configured

Tools. Gradle. JS

KT-38170 Investigate how to improve migration experience from pre 1.4.0 DSL to the new one

KT-39654 Default CSS settings in webpack has priority over user’s settings

KT-39842 Kotlin/JS Gradle DSL: peerNpm dependency fails

KT-40048 [Gradle, JS] Deprecate kotlin-frontend plugin

KT-40067 [Gradle, JS] Public package.json for mixed JS/TS project

KT-40210 Fail the build when Kotlin/JS target is not (properly) configured

KT-40320 Gradle JS: make migration to the new Gradle DSL smoother

Tools. Gradle. Multiplatform

KT-32239 Custom configurations inside Kotlin JVM Gradle projects can’t properly resolve multiplatform dependencies

KT-39897 [Commonizer] Fast-pass for library fragments absent for some targets

Tools. J2K

KT-39739 J2K: Access is allowed from event dispatch thread with IW lock only

Tools. kapt

KT-34604 KAPT: Flaky NPE through org.jetbrains.kotlin.kapt3.base.ProcessorLoader.doLoadProcessors

KT-36302 TypeTreeVisitor.visitMemberSelect IllegalStateException: node.sym must not be null on JDK 11

KT-39876 KAPT: Serialization of classpath structure is incorrect if there are dependencies between types in jar/dir

1.4-M3

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 strin…