[Release News] Kotlin v1.4.20 released!

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Kotlin v1.4.20 has been released.

CHANGELOG

Android

• KT-42121 Deprecate Kotlin Android Extensions compiler plugin
• KT-42267 Platform declaration clash error in IDE when using kotlinx.android.parcel.Parcelize
• KT-42406 Long or infinite code analysis on simple files modification

Backend. Native

• KT-27534 Bridges to Nothing-returning methods have incorrect signature
• KT-30284 Native: Nothing? type for expression override and crash
• KT-36430 Optimize when with in range cases
• KT-38787 Missing optimization for “in range” check
• KT-39100 Make Native behaviour of property initialization consistent with JVM
• KT-39798 Override equals/hashCode in functional interface wrappers on Native
• KT-39800 equals/hashCode on adapted function references on Native
• KT-41394 Compilation failed: Backend Internal error: Exception during IR lowering
• KT-41907 Framework test segfaults on GC on watchos_x86 compiled with -opt

Compiler

New Features

• KT-21147 JEP 280: Indify String Concatenation (StringConcatFactory)
• KT-34178 Scripts should be able to access imports objects
• KT-35549 Support kotlin-android-extensions in JVM IR backend (for use with Jetpack Compose projects)
• KT-31567 Support special semantics for underscore-named catch block parameters

Performance Improvements

• KT-20571 Coroutines: Reduce number of local variables stored at suspension point
• KT-28016 Coroutine state-machines spill/unspill shall be optimized using data-flow analysis
• KT-33394 UI freezes triggered by QualifiedExpressionResolver.resolveToPackageOrClassPrefix
• KT-36814 Support optimized delegated properties in JVM_IR
• KT-36829 Optimize ‘in’ expressions (operator fun contains) in JVM_IR
• KT-41741 NI: “AssertionError: Empty intersection for types” with generic Java collection
• KT-42195 NI: prohibitively long compilation time for values of nested data structures with type inference
• KT-42221 Native compiler never finishes frontend phase after migrating to Kotlin 1.4.10

Fixes

• KT-11713 Refine visibility check for synthetic property with protected setter
• KT-16222 Coroutine should be clearing any internal state as soon as possible to avoid memory leaks
• KT-25519 Extra inline marks inside suspending function callable reference bytecode
• KT-33226 Object INSTANCE field not annotated with NotNull in generated bytecode
• KT-35495 FIR: forbid non-Java synthetic properties
• KT-35651 Kotlin stdlib has greater resolution priority than jars added via @file:DependsOn annotation
• KT-35716 Using @JvmOverloads in @JvmStatic functions in interface companion objects causes a ClassFormatError
• KT-35730 FIR: consider creating fake overrides for objects
• KT-36951 IllegalStateException: Expected some types: Throwing exception when there is a type parameter upper bound for itself
• KT-37321 [FIR] Support java array in type argument
• KT-37431 [FIR] Support Builder Inference
• KT-38272 FIR2IR: use lazy IR symbols for externals & fake overrides
• KT-38333 FIR: CCE on red code with assignment used as expression
• KT-38334 FIR: CCE when resolving try-as-expression
• KT-38336 FIR: NPE with corrupted numeric constant literal
• KT-38397 FIR: Exception while resolving contract definition
• KT-38444 [FIR] Invoke extension lambda with safe call
• KT-38470 FIR: ConeDefinitelyNotNullType in signature
• KT-38471 FIR: ConeIntersectionType in signature
• KT-38925 Internal error: wrong bytecode generated. (AssertionError: int type expected, but null was found in basic frames)
• KT-38989 FIR: Refine sealed classes exhaustiveness in case of sealed subclass
• KT-38992 FIR: Refine type resolution for inner classes
• KT-39000 FIR: Support smartcast after reference equality check
• KT-39005 FIR: Resolve plusAssign in a dependent context
• KT-39008 FIR: Investigate strange effect of type alias and not-nullable bound on inference
• KT-39012 FIR: Inference doesn’t get through elvis to lambda parameter
• KT-39028 FIR: Strange resolution to synthetic property with implicit extension receiver while there’s an explicit receiver
• KT-39032 FIR: Ambiguity in member scope of a type parameter with multiple bounds
• KT-39033 FIR: Ambiguity when calling generic overridden property
• KT-39034 FIR: Support nested extension function types
• KT-39040 FIR: Deserialize annotations from compiled Kotlin binaries
• KT-39043 FIR: Bare types incorrectly work with type aliases
• KT-39044 FIR: Add fillInStackTrace to member scope of kotlin.Throwable
• KT-39046 FIR: Implicit types in lambdas left when call argument is a type cast
• KT-39048 FIR: Inference fails with integer literal used as Comparable
• KT-39050 FIR: Type resolver doesn’t see nested classes from super class of a local class
• KT-39070 FIR: Ambiguity on super calls to hashCode/equals when having super interface and class
• KT-39072 FIR: Subtyping check doesn’t affect nullability of safe-call receiver
• KT-39076 FIR: Synthetic property is not a var because of @Nullable annotation on parameter
• KT-39080 FIR: Smart casts remain incorrect if lambda is present in when branch
• KT-39374 Wrong bytecode generated for suspend function call with EXACTLY_ONCE lambda capturing a variable initialized in when-subject
• KT-39621 [FIR] Support when exhaustiveness checker for java enums
• KT-40135 JVM IR does not generate restricted suspend lambdas
• KT-40382 Missing proper jvmSignature for synthesized equals/hashCode/toString in inline classes
• KT-40605 JVM IR: IndexOutOfBoundsException caused by inner class passed to generic outer class method with Nothing type argument
• KT-40664 JVM: No bounds check in optimization of ULong in UInt..UInt
• KT-40665 JVM: No resolved function check when optimizing in/contains with mismatched bound types
• KT-41014 FIR2IR: when/where/how to determine the presence of a backing field for a property
• KT-41018 FIR2IR: sort members during de/serialization
• KT-41144 False positive “Redundant spread operator” in when statement and generic vararg argument
• KT-41218 HMPP: arrayList declarations are visible both from stdlib-common and stdlib-jvm and lead to false-positive resolution ambiguity in IDE
• KT-41374 JVM / IR: NoSuchMethodError in Android project compiler caused by combination of inline classes and coroutines
• KT-41388 NI: Backend Internal error: Exception during IR lowering
• KT-41429 Inline class returned from suspend function should be boxed on resume path
• KT-41465 JVM / IR: “AssertionError: inconsistent parent function for CLASS LAMBDA_IMPL CLASS name” caused by inline method call into multiple constructors
• KT-41484 JVM IR: support -Xemit-jvm-type-annotations
• KT-41668 JVM IR: incorrect enclosing constructor for lambdas in initializers of inner classes
• KT-41669 JVM IR: incorrect hashCode intrinsic is used in JVM target 1.8 for generic type substituted with primitive
• KT-41693 NI: Type inference in nested expression incorrectly assumes non-nullable return type of Java function, causing NullPointerException
• KT-41729 NI: UnsupportedOperationException with invalid callable reference
• KT-41761 JVM IR: CCE from backend on generating typeOf for non-reified type parameter with star projection in upper bound
• KT-41789 Missing DebugMetadata in inlined suspend lambda
• KT-41913 NI: Kotlin 1.4 type inference breaks valid code
• KT-41934 NI: a type variable for lambda parameter has been inferred to nullable type instead of not null one
• KT-42005 JVM / IR: “NullPointerException: Parameter specified as non-null is null” when toString is called on inline class with not primitive property
• KT-42450 NI: “IllegalStateException: Error type encountered: NonFixed:” with coroutines
• KT-42523 Missed DefaultImpls for interface in -jvm-default=all mode on inheriting it from interface compiled in old scheme
• KT-42524 Wrong specialization diagnostic is reported on inheriting from java interface with default with -Xjvm-default=all-compatibility
• KT-42546 HMPP: incorrect subtyping of nullable types & overload resolution ambiguity on using and expect-function declaration with nullable expect in a signature
• KT-17691 Wrong argument order in resolved call with varargs
• KT-25114 Prohibit @JvmStatic on functions in private companions
• KT-33917 Prohibit to expose anonymous types from private inline functions
• KT-35870 Forbid secondary enum class constructors which do not delegate to the primary constructor
• KT-39098 NI: parameter of anonymous function can be inferred to Any? if another parameter’s type is specified
• KT-41176 NI with Gson: “ClassCastException: java.util.ArrayList cannot be cast to java.lang.Void”
• KT-41194 ClassCastException on returning Result.failure from lambda within suspend function
• KT-42438 NI: ClassCastException: cannot be cast to java.lang.Void caused by when statement in run function
• KT-42699 False positive NON_JVM_DEFAULT_OVERRIDES_JAVA_DEFAULT diagnostic in new jvm-default modes
• KT-42706 Kotlin 1.4 infers generic is Nothing instead of actual Foo class (Android project)

Docs & Examples

• KT-42318 No documentation for kotlin.js.js

IDE

New Features

• KT-20775 More kotlin kinds in new kotlin file/class menu
• KT-31331 Improve: Optimize Import should remove unused unresolved imports
• KT-31500 Smart enter: support get() clause
• KT-39231 Injection: Add receiver of kotlin.text.toPattern to standard Kotlin injections
• KT-39844 Add specific highlight for Enum class

Performance Improvements

• KT-39353 Implement EnterBetweenBracesNoCommitDelegate
• KT-39720 A lot of freezes in Kotlin project
• KT-41634 Deadlock in org.jetbrains.kotlin.idea.framework.LibraryEffectiveKindProviderImpl.getEffectiveKind
• KT-41936 Impossible to work with Kotlin 1.4 in 202 idea, idea eats all cpu

Fixes

• KT-10790 “Move statement up” for @file-targeted annotation moves package declaration to bottom of file
• KT-15262 “Generate toString()” is ignoring property if it has a getter
• KT-24352 Method separators: displayed between properties, not displayed between companion object and function
• KT-29364 “Extend selection” can’t select lambda body with parameters
• KT-32403 Clickable links in annotation parameters (like in TODOs)
• KT-32409 Organizing imports should not remove imports while there are unresolved symbols
• KT-34566 Too small indent after line break for multi line strings
• KT-34587 “Move statement down” doesn’t work for statement in constructor with end-of-line comment
• KT-34705 “Move statement down” for penultimate statement with end-of-line comment in constructor leads to moving comma to the end of comment
• KT-34707 “Move statement up” for last statement with end-of-line comment in constructor leads to moving comma to the end of comment
• KT-35424 FIR IDE: Kotlin project does not see stdlib
• KT-35732 URLs in String literals are not clickable
• KT-35859 Language injection doesn’t work with named arguments in different position
• KT-37210 UAST: KtLightClassForSourceDeclaration.isInheritor sometimes returns the wrong result
• KT-37219 File level OptIn annotation is not recognized by the IDE
• KT-38959 IDE: False negative EXPLICIT_DELEGATION_CALL_REQUIRED, “IllegalArgumentException: Range must be inside element being annotated”
• KT-39398 Wrong import of unrelated object member is suggested for receiver
• KT-39457 Separate decompiled declarations Light implementation from LightClasses infrastructure
• KT-39899 KotlinOptimizeImportsRefactoringHelper: ISE: Attempt to modify PSI for non-committed Document
• KT-40578 UAST: write accesses to Kotlin properties should resolve to setter
• KT-41290 KotlinClassViaConstructorUSimpleReferenceExpression resolves to PsiMethod instead of PsiClass
• KT-42029 HMPP, IDE: NPE from FacetSerializationKt.getFacetPlatformByConfigurationElement on project opening
• KT-43202 On 1.4.20-RC version AS ask for xml compatibility update for EAP version of plugin
• KT-42883 No highlighting for elements marked as @Deprecated in stdlib

IDE. Android

• KT-42406 Long or infinite code analysis on simple files modification
• KT-42061 Highlighting is broken in Android activity
• KT-41930 Android Studio 4.2 cannot start after updating to 1.4.20 plugin with error: Missing essential plugin: org.jetbrains.android

IDE. Completion

• KT-26235 Kotlin methods/fields don’t have icons in Java completion

IDE. Debugger

• KT-37486 Kotlin plugin keeps reference to stream debugger support classes after stream debugger plugin is disabled
• KT-38659 Evaluate Expression: toString() on variable returns error when breakpoint is in commonTest sourceset
• KT-39309 Debugger: Prolonged “Collecting data” for variables when breakpoint is inside respondHtml
• KT-39435 “Collecting data…” in debugger variables view never finishes
• KT-39717 Debugger shows “Collecting data…” forever for instances of some class
• KT-40386 Memory leak detected: ‘org.jetbrains.kotlin.idea.debugger.coroutine.view.XCoroutineView’
• KT-40635 Coroutines Debugger: make IDE plugin accept coroutines 1.3.8-rc* versions as well
• KT-41505 Coroutines Debugger: “Access is allowed from event dispatch thread with IW lock only.”

IDE. Decompiler, Indexing, Stubs

• KT-28732 Stub file element types should be registered early enough
• KT-41346 IDE: “AssertionError: Stub type mismatch: USER_TYPE!=REFERENCE_EXPRESSION” with CollapsedDumpParser class from IDEA SDK
• KT-41859 File analysis never ending with kotlinx.cli (AssertionError: Stub type mismatch: TYPEALIAS!=CLASS)
• KT-41640 “Project roots have changed” happened during indexing because of org.jetbrains.kotlin.idea.core.script.ucache.ScriptClassRootsUpdater$notifyRootsChanged increases overall indexing time.
• KT-41646 “AssertionError: ContentElementType: FILE”; Code analysis never finishes on some files from my project

IDE. Gradle Integration

• KT-34271 Support pureKotlinSourceFolders for MPP projects
• KT-37106 Gradle + IDE integration: on creating source roots from Project tree IDEA creates incorrect settings
• KT-38830 addTransitiveDependenciesOnImplementedModules performance is slowing down Android Studio Gradle Sync
• KT-41703 Kotlin plugin not functional: PluginException: While loading class org.jetbrains.kotlin.idea.core.script.KotlinScriptDependenciesClassFinder

IDE. Gradle. Script

• KT-35092 “Unable to get Gradle home directory” popup and no build.gradle.kts highlighting right after creating a new project
• KT-37590 Wrong notification for precompiled build script
• KT-39523 Go to Declaration navigates to decompiled classfile instead of sources in case of jumping to Gradle plugin sources in buildSrc
• KT-39542 EA-218043: java.util.NoSuchElementException: No element of given type found (GradleBuildRootsManager)
• KT-39790 List of standalone script should be saved between IDE restarts
• KT-39910 build.gradle.kts isn’t highlighted after import
• KT-39916 init.gradle.kts isn’t highlighted
• KT-40243 gradle.kts: standalone script under build root isn’t highlighted as standalone
• KT-41141 Gradle Kotlin DSL: “cannot access ‘java.lang.Comparable’. Check your module classpath” with empty JDK in Project structure
• KT-41281 Multiple Script Definitions warning shown in git project having multiple Gradle projects

IDE. Hints

• KT-32368 Rework Inline hints settings so that they look appropriate with the new UI in 2019.3
• KT-38027 Support Code Vision feature in Kotlin
• KT-42014 ClassNotFoundException in Android Studio 4.2 after installing 1.4.20 plugin

IDE. Hints. Parameter Info

• KT-24172 Parameter info marks signature as inapplicable when using argument labels
• KT-41617 Parameter Info shows nothing inside already present type arguments of supertype
• KT-41645 Add support for mixed named arguments to parameter info popup

IDE. Inspections and Intentions

New Features

• KT-14578 Suggest “Convert lambda to reference” intention for generic extension function
• KT-19321 Warn if method with nullable return type always returns non-null
• KT-20718 Add a quick fix for “this class has no constructor” error on ‘expect’ annotation classes
• KT-21223 Add inspection for incomplete destructuring
• KT-22420 Intention to replace a = b with b.also { a = it }
• KT-39930 Add inspection for nullable Boolean in if condition
• KT-40016 Replace ‘a.toLowerCase() == b.toLowerCase()’ with ‘a.equals(b, ignoreCase = true)’ inspection
• KT-40283 Inspection which replaces also/apply with nested forEach to onEach
• KT-40769 Add intention to replace isBlank/isNotBlank method negation

Fixes

• KT-12222 Intention ‘Convert to block body’ should take nullability of overriden method into account when expression is of platform type
• KT-14395 Lambda to Reference doesn’t work for generic types
• KT-15846 ‘Change lambda expression return type’ quick fix does nothing
• KT-15944 IDEA doesn’t suggest to replace deprecated get set operator functions when it used as operator
• KT-17222 “Convert reference to lambda” creates red code for method with default argument values
• KT-18125 “Wrap with let {…}” intention not available in all cases
• KT-20438 Naming convention inspections: factory functions that are named like classes are flagged
• KT-24138 Incorrect behavior in “convert reference to lambda” with new inference enabled, on function reference with default arguments
• KT-29844 “Create class from usage” should mark constructor of created class as internal if its parameters have internal visibility
• KT-30928 “Show hints for suspend calls” is too easy to enable and hard to disable
• KT-31749 “Surround with null check” produces incorrect check for ‘in’ expression
• KT-32963 Don’t suggest java directory of a JVM source set in multiplatform project as a target for Create actual quick fix
• KT-33211 Quickfix “add parameter” for method references should infer functional type instead of KFunction
• KT-33258 “Merge 'if’s” intention drops comment before nested if
• KT-34572 Convert to block body action improperly works with suppress annotations
• KT-35128 Intention Convert member to extension hides property delegate text with single line comment
• KT-35214 Intention Put parameters on one line: don’t suggest if parameters has end-of-line comments
• KT-35320 False positive “Replace explicit parameter ‘x’ with ‘it’” in ‘when’ expression which returns lambda
• KT-35525 False positive intention for ‘run’: “Convert to ‘let’” when invoked without receiver
• KT-35526 Intention “Eliminate argument of ‘when’” is broken for ‘when’ expression without ‘else’ branch
• KT-35805 FoldInitializerAndIfToElvis: should not add new line for multiline initializer
• KT-36051 IfThenToSafeAccessInspection: do not report if condition is SENSELESS_COMPARISON
• KT-37748 “Convert anonymous function to lambda expression” intention does not add necessary lambda type parameter
• KT-37841 IllegalStateException after “add non-null asserted call” on nullable function reference
• KT-38139 False negative “Add suspend modifier” quickfix when suspend function is called in inline lambda
• KT-38267 False positive "Call on collection type may be…

Link: https://github.com/JetBrains/kotlin/releases/tag/v1.4.20

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