New J2K: use nullable type for unknown for public declarations & prepare for mutability inference

#KT-32518 fixed

compiler/psi/src/org/jetbrains/kotlin/psi/KtClassBody.kt

@@ -46,7 +46,7 @@ class KtClassBody : KtElementImplStub<KotlinPlaceHolderStub<KtClassBody>>, KtDec
     val properties: List<KtProperty>
         get() = getStubOrPsiChildrenAsList(KtStubElementTypes.PROPERTY)
 
-    val functions: List<KtFunction>
+    val functions: List<KtNamedFunction>
         get() = getStubOrPsiChildrenAsList(KtStubElementTypes.FUNCTION)
 
     val enumEntries: List<KtEnumEntry>

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/BoundTypeCalculator.kt

@@ -36,37 +36,41 @@ interface BoundTypeCalculator {
     ): BoundType
 }
 
-class BoundTypeCalculatorImpl(
+open class BoundTypeCalculatorImpl(
     private val resolutionFacade: ResolutionFacade,
     private val enhancer: BoundTypeEnhancer
 ) : BoundTypeCalculator {
     private val cache = mutableMapOf<KtExpression, BoundType>()
 
-    override fun expressionsWithBoundType() = cache.toList()
+    final override fun expressionsWithBoundType() = cache.toList()
 
-    override fun KtExpression.boundType(inferenceContext: InferenceContext): BoundType = cache.getOrPut(this) {
+    final override fun KtExpression.boundType(inferenceContext: InferenceContext): BoundType = cache.getOrPut(this) {
         calculateBoundType(inferenceContext, this)
     }
 
-    private fun calculateBoundType(inferenceContext: InferenceContext, expression: KtExpression): BoundType = when {
-        expression.isNullExpression() -> BoundType.NULL
-        expression is KtParenthesizedExpression -> expression.expression?.boundType(inferenceContext)
-        expression is KtConstantExpression
-                || expression is KtStringTemplateExpression
-                || expression.node?.elementType == KtNodeTypes.BOOLEAN_CONSTANT
-                || expression is KtBinaryExpression ->
-            BoundType.LITERAL
-        expression is KtQualifiedExpression -> expression.toBoundTypeAsQualifiedExpression(inferenceContext)
-        expression is KtBinaryExpressionWithTypeRHS -> expression.toBoundTypeAsCastExpression(inferenceContext)
-        expression is KtNameReferenceExpression -> expression.toBoundTypeAsReferenceExpression(inferenceContext)
-        expression is KtCallExpression -> expression.toBoundTypeAsCallableExpression(null, inferenceContext)
-        expression is KtLambdaExpression -> expression.toBoundTypeAsLambdaExpression(inferenceContext)
-        expression is KtLabeledExpression -> expression.baseExpression?.boundType(inferenceContext)
-        expression is KtIfExpression -> expression.toBoundTypeAsIfExpression(inferenceContext)
-        else -> null
-    }?.let { boundType ->
-        enhancer.enhance(expression, boundType, inferenceContext)
-    } ?: BoundType.LITERAL
+    open fun interceptCalculateBoundType(inferenceContext: InferenceContext, expression: KtExpression): BoundType? =
+        null
+
+    private fun calculateBoundType(inferenceContext: InferenceContext, expression: KtExpression): BoundType =
+        interceptCalculateBoundType(inferenceContext, expression) ?: when {
+            expression.isNullExpression() -> BoundType.NULL
+            expression is KtParenthesizedExpression -> expression.expression?.boundType(inferenceContext)
+            expression is KtConstantExpression
+                    || expression is KtStringTemplateExpression
+                    || expression.node?.elementType == KtNodeTypes.BOOLEAN_CONSTANT
+                    || expression is KtBinaryExpression ->
+                BoundType.LITERAL
+            expression is KtQualifiedExpression -> expression.toBoundTypeAsQualifiedExpression(inferenceContext)
+            expression is KtBinaryExpressionWithTypeRHS -> expression.toBoundTypeAsCastExpression(inferenceContext)
+            expression is KtNameReferenceExpression -> expression.toBoundTypeAsReferenceExpression(inferenceContext)
+            expression is KtCallExpression -> expression.toBoundTypeAsCallableExpression(null, inferenceContext)
+            expression is KtLambdaExpression -> expression.toBoundTypeAsLambdaExpression(inferenceContext)
+            expression is KtLabeledExpression -> expression.baseExpression?.boundType(inferenceContext)
+            expression is KtIfExpression -> expression.toBoundTypeAsIfExpression(inferenceContext)
+            else -> null
+        }?.let { boundType ->
+            enhancer.enhance(expression, boundType, inferenceContext)
+        } ?: BoundType.LITERAL
 
     private fun KtIfExpression.toBoundTypeAsIfExpression(inferenceContext: InferenceContext): BoundType? {
         val isNullLiteralPossible = then?.isNullExpression() == true || `else`?.isNullExpression() == true
@@ -166,7 +170,7 @@ class BoundTypeCalculatorImpl(
         return selectorExpression.toBoundTypeAsCallableExpression(receiverBoundType, inferenceContext)
     }
 
-    override fun KotlinType.boundType(
+    final override fun KotlinType.boundType(
         typeVariable: TypeVariable?,
         contextBoundType: BoundType?,
         call: ResolvedCall<*>?,
@@ -220,8 +224,9 @@ class BoundTypeCalculatorImpl(
                 when {
                     containingDeclaration == call?.candidateDescriptor?.original -> {
                         val returnTypeVariable = inferenceContext.typeElementToTypeVariable[
-                                call.call.typeArguments.getOrNull(target.index)?.typeReference?.typeElement ?: return null
-                        ] ?: return null
+                                call.call.typeArguments.getOrNull(target.index)?.typeReference?.typeElement
+                                    ?: return BoundType.STAR_PROJECTION
+                        ] ?: return BoundType.STAR_PROJECTION
                         BoundTypeImpl(
                             TypeVariableLabel(returnTypeVariable),
                             returnTypeVariable.typeParameters
@@ -238,8 +243,9 @@ class BoundTypeCalculatorImpl(
                     // `this` or `super` call case
                     containingDeclaration == call?.candidateDescriptor.safeAs<ConstructorDescriptor>()?.constructedClass -> {
                         val returnTypeVariable = inferenceContext.typeElementToTypeVariable[
-                                call?.call?.typeArguments?.getOrNull(target.index)?.typeReference?.typeElement ?: return null
-                        ] ?: return null
+                                call?.call?.typeArguments?.getOrNull(target.index)?.typeReference?.typeElement
+                                    ?: return BoundType.STAR_PROJECTION
+                        ] ?: return BoundType.STAR_PROJECTION
                         BoundTypeImpl(
                             TypeVariableLabel(returnTypeVariable),
                             returnTypeVariable.typeParameters

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/Constraint.kt

@@ -54,28 +54,8 @@ class LiteralBound private constructor(val state: State) : ConstraintBound() {
     }
 }
 
-val TypeVariable.constraintBound: TypeVariableBound
-    get() = TypeVariableBound(this)
-
-val State.constraintBound: LiteralBound
-    get() = when (this) {
-        State.LOWER -> LiteralBound.LOWER
-        State.UPPER -> LiteralBound.UPPER
-        State.UNKNOWN -> LiteralBound.UNKNOWN
-    }
-
-val BoundTypeLabel.constraintBound: ConstraintBound?
-    get() = when (this) {
-        is TypeVariableLabel -> typeVariable.constraintBound
-        is TypeParameterLabel -> null
-        is GenericLabel -> null
-        StarProjectionLabel -> null
-        NullLiteralLabel -> LiteralBound.UPPER
-        LiteralLabel -> LiteralBound.LOWER
-    }
-
-val BoundType.constraintBound: ConstraintBound?
-    get() = when (this) {
-        is BoundTypeImpl -> label.constraintBound
-        is WithForcedStateBoundType -> forcedState.constraintBound
-    }
+fun State.constraintBound(): LiteralBound = when (this) {
+    State.LOWER -> LiteralBound.LOWER
+    State.UPPER -> LiteralBound.UPPER
+    State.UNKNOWN -> LiteralBound.UNKNOWN
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/ConstraintBoundProvider.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.nj2k.inference.common
+
+interface ConstraintBoundProvider {
+    fun TypeVariable.constraintBound(): TypeVariableBound
+    fun BoundType.constraintBound(): ConstraintBound?
+    fun BoundTypeLabel.constraintBound(): ConstraintBound?
+}
+
+abstract class ConstraintBoundProviderImpl : ConstraintBoundProvider {
+    final override fun TypeVariable.constraintBound(): TypeVariableBound =
+        TypeVariableBound(this)
+
+    final override fun BoundType.constraintBound(): ConstraintBound? = when (this) {
+        is BoundTypeImpl -> label.constraintBound()
+        is WithForcedStateBoundType -> forcedState.constraintBound()
+    }
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/ConstraintBuilder.kt

@@ -13,8 +13,9 @@ import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 @Suppress("unused")
 class ConstraintBuilder(
     private val inferenceContext: InferenceContext,
-    private val boundTypeCalculator: BoundTypeCalculator
-) : BoundTypeCalculator by boundTypeCalculator {
+    private val boundTypeCalculator: BoundTypeCalculator,
+    private val constraintBoundProvider: ConstraintBoundProvider
+) : BoundTypeCalculator by boundTypeCalculator, ConstraintBoundProvider by constraintBoundProvider {
     private val constraints = mutableListOf<Constraint>()
 
     fun TypeVariable.isSubtypeOf(supertype: BoundType, priority: ConstraintPriority) {
@@ -39,7 +40,7 @@ class ConstraintBuilder(
 
     fun KtExpression.isTheSameTypeAs(other: State, priority: ConstraintPriority) {
         boundType().label.safeAs<TypeVariableLabel>()?.typeVariable?.let { typeVariable ->
-            constraints += EqualsConstraint(typeVariable.constraintBound, other.constraintBound, priority)
+            constraints += EqualsConstraint(typeVariable.constraintBound(), other.constraintBound(), priority)
         }
     }
 
@@ -104,8 +105,8 @@ class ConstraintBuilder(
 
         if (typeVariable !in ignoreTypeVariables && other.typeVariable !in ignoreTypeVariables) {
             constraints += EqualsConstraint(
-                constraintBound ?: return,
-                other.constraintBound ?: return,
+                constraintBound() ?: return,
+                other.constraintBound() ?: return,
                 priority
             )
         }
@@ -121,8 +122,8 @@ class ConstraintBuilder(
         }
 
         constraints += SubtypeConstraint(
-            constraintBound ?: return,
-            supertype.constraintBound ?: return,
+            constraintBound() ?: return,
+            supertype.constraintBound() ?: return,
             priority
         )
     }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/ConstraintsCollectorAggregator.kt

@@ -14,14 +14,15 @@ import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 
 class ConstraintsCollectorAggregator(
     private val resolutionFacade: ResolutionFacade,
-    private val collectors: List<ConstraintsCollector>
+    private val constraintBoundProvider: ConstraintBoundProvider,
+    val collectors: List<ConstraintsCollector>
 ) {
     fun collectConstraints(
         boundTypeCalculator: BoundTypeCalculator,
         inferenceContext: InferenceContext,
         elements: List<KtElement>
     ): List<Constraint> {
-        val constraintsBuilder = ConstraintBuilder(inferenceContext, boundTypeCalculator)
+        val constraintsBuilder = ConstraintBuilder(inferenceContext, boundTypeCalculator, constraintBoundProvider)
         for (element in elements) {
             element.forEachDescendantOfType<KtElement> { innerElement ->
                 if (innerElement.getStrictParentOfType<KtImportDirective>() != null) return@forEachDescendantOfType

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/ContextCollector.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.forEachDescendantOfType
+import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.types.KotlinType
@@ -29,13 +30,13 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
     private fun KtTypeReference.classReference(): ClassReference? =
         analyze()[BindingContext.TYPE, this]?.classReference()
 
-    private fun KtTypeElement.toData(): TypeElementData {
-        val typeReference = parent as? KtTypeReference ?: return TypeElementDataImpl(this)
-        val typeParameterDescriptor = analyze(resolutionFacade)[BindingContext.TYPE, typeReference]
-            ?.constructor
-            ?.declarationDescriptor
-            ?.safeAs<TypeParameterDescriptor>() ?: return TypeElementDataImpl(this)
-        return TypeParameterElementData(this, typeParameterDescriptor)
+    private fun KtTypeElement.toData(): TypeElementData? {
+        val typeReference = parent as? KtTypeReference ?: return null
+        val type = analyze(resolutionFacade)[BindingContext.TYPE, typeReference] ?: return null
+        val typeParameterDescriptor = type.constructor
+            .declarationDescriptor
+            ?.safeAs<TypeParameterDescriptor>() ?: return TypeElementDataImpl(this, type)
+        return TypeParameterElementData(this, type, typeParameterDescriptor)
     }
 
     fun collectTypeVariables(elements: List<KtElement>): InferenceContext {
@@ -43,7 +44,7 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
         val typeElementToTypeVariable = mutableMapOf<KtTypeElement, TypeVariable>()
         val typeBasedTypeVariables = mutableListOf<TypeBasedTypeVariable>()
 
-        fun KtTypeReference.toBoundType(defaultState: State? = null): BoundType? {
+        fun KtTypeReference.toBoundType(owner: TypeVariableOwner, defaultState: State? = null): BoundType? {
             val typeElement = typeElement ?: return null
             val classReference = classReference() ?: NoClassReference
 
@@ -58,9 +59,7 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
                         classReference.descriptor.declaredTypeParameters
                     ) { typeArgument, typeParameter ->
                         TypeParameter(
-                            if (typeArgument == null) {
-                                BoundTypeImpl(StarProjectionLabel, emptyList())
-                            } else typeArgument.toBoundType() ?: BoundType.STAR_PROJECTION,
+                            typeArgument?.toBoundType(owner) ?: BoundType.STAR_PROJECTION,
                             typeParameter.variance
                         )
                     }
@@ -75,7 +74,8 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
                 val typeVariable = TypeElementBasedTypeVariable(
                     classReference,
                     typeArguments,
-                    typeElement.toData(),
+                    typeElement.toData() ?: return null,
+                    owner,
                     state
                 )
                 typeElementToTypeVariable[typeElement] = typeVariable
@@ -116,6 +116,12 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
 
         val substitutors = mutableMapOf<ClassDescriptor, ClassSubstitutor>()
 
+        fun isOrAsExpression(typeReference: KtTypeReference) {
+            val typeElement = typeReference.typeElement ?: return
+            val typeVariable = typeReference.toBoundType(OtherTarget)?.typeVariable ?: return
+            typeElementToTypeVariable[typeElement] = typeVariable
+        }
+
         for (element in elements) {
             element.forEachDescendantOfType<KtExpression> { expression ->
                 if (expression is KtCallableDeclaration
@@ -124,24 +130,31 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
                             || expression is KtNamedFunction)
                 ) run {
                     val typeReference = expression.typeReference ?: return@run
-                    val typeVariable = typeReference.toBoundType()?.typeVariable ?: return@run
+                    val typeVariable = typeReference.toBoundType(
+                        when (expression) {
+                            is KtParameter -> expression.getStrictParentOfType<KtFunction>()?.let(::FunctionParameter)
+                            is KtFunction -> FunctionReturnType(expression)
+                            is KtProperty -> Property(expression)
+                            else -> null
+                        } ?: OtherTarget
+                    )?.typeVariable ?: return@run
                     declarationToTypeVariable[expression] = typeVariable
                 }
 
                 if (expression is KtTypeParameterListOwner) {
                     for (typeParameter in expression.typeParameters) {
-                        typeParameter.extendsBound?.toBoundType(defaultState = State.UPPER)
+                        typeParameter.extendsBound?.toBoundType(OtherTarget, defaultState = State.UPPER)
                     }
                     for (constraint in expression.typeConstraints) {
-                        constraint.boundTypeReference?.toBoundType(defaultState = State.UPPER)
+                        constraint.boundTypeReference?.toBoundType(OtherTarget, defaultState = State.UPPER)
                     }
                 }
 
                 when (expression) {
-                    is KtClass -> {
+                    is KtClassOrObject -> {
                         for (entry in expression.superTypeListEntries) {
                             for (argument in entry.typeReference?.typeElement?.typeArgumentsAsTypes ?: continue) {
-                                argument.toBoundType()
+                                argument.toBoundType(OtherTarget)
                             }
                         }
                         val descriptor =
@@ -160,7 +173,7 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
                     }
                     is KtCallExpression ->
                         for (typeArgument in expression.typeArguments) {
-                            typeArgument.typeReference?.toBoundType()
+                            typeArgument.typeReference?.toBoundType(TypeArgument)
                         }
                     is KtLambdaExpression -> {
                         val context = expression.analyze(resolutionFacade)
@@ -169,10 +182,11 @@ abstract class ContextCollector(private val resolutionFacade: ResolutionFacade)
                         declarationToTypeVariable[expression.functionLiteral] = typeVariable
                     }
                     is KtBinaryExpressionWithTypeRHS -> {
-                        val typeReference = expression.right ?: return@forEachDescendantOfType
-                        val typeElement = typeReference.typeElement ?: return@forEachDescendantOfType
-                        val typeVariable = typeReference.toBoundType()?.typeVariable ?: return@forEachDescendantOfType
-                        typeElementToTypeVariable[typeElement] = typeVariable
+                        isOrAsExpression(expression.right ?: return@forEachDescendantOfType)
+
+                    }
+                    is KtIsExpression -> {
+                        isOrAsExpression(expression.typeReference ?: return@forEachDescendantOfType)
                     }
                 }
             }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/DefaultStateProvider.kt

@@ -0,0 +1,10 @@
+/*
+* Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+*/
+
+package org.jetbrains.kotlin.nj2k.inference.common
+
+abstract class DefaultStateProvider {
+    abstract fun defaultStateFor(typeVariable: TypeVariable): State
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/InferenceFacade.kt

@@ -14,6 +14,7 @@ class InferenceFacade(
     private val constraintsCollectorAggregator: ConstraintsCollectorAggregator,
     private val boundTypeCalculator: BoundTypeCalculator,
     private val stateUpdater: StateUpdater,
+    private val defaultStateProvider: DefaultStateProvider,
     private val renderDebugTypes: Boolean = false,
     private val printDebugConstraints: Boolean = false
 ) {
@@ -22,7 +23,7 @@ class InferenceFacade(
         val constraints = constraintsCollectorAggregator.collectConstraints(boundTypeCalculator, inferenceContext, elements)
 
         val initialConstraints = if (renderDebugTypes) constraints.map { it.copy() } else null
-        Solver(inferenceContext, printDebugConstraints).solveConstraints(constraints)
+        Solver(inferenceContext, printDebugConstraints, defaultStateProvider).solveConstraints(constraints)
 
         if (renderDebugTypes) {
             with(DebugPrinter(inferenceContext)) {

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/Solver.kt

@@ -5,15 +5,15 @@
 
 package org.jetbrains.kotlin.nj2k.inference.common
 
-import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 
 internal class Solver(
-    private val analysisContext: InferenceContext,
-    private val printConstraints: Boolean
+    private val inferenceContext: InferenceContext,
+    private val printConstraints: Boolean,
+    private val defaultStateProvider: DefaultStateProvider
 ) {
-    private val printer = DebugPrinter(analysisContext)
+    private val printer = DebugPrinter(inferenceContext)
 
     private fun List<Constraint>.printDebugInfo(step: Int) =
         with(printer) {
@@ -24,7 +24,7 @@ internal class Solver(
                 }
                 println()
                 println("type variables:")
-                for (typeVariable in analysisContext.typeVariables) {
+                for (typeVariable in inferenceContext.typeVariables) {
                     println("${typeVariable.name} := ${typeVariable.state}")
                 }
                 println("---------------\n")
@@ -55,9 +55,11 @@ internal class Solver(
                 }
             }
             if (!somethingChanged) {
-                val typeVariable = mutableConstraints.getTypeVariableAsEqualsOrUpperBound()
+                val typeVariable =
+                    mutableConstraints.getTypeVariableAsEqualsOrUpperBound()
+                        ?: inferenceContext.typeVariables.firstOrNull { !it.isFixed }
                 if (typeVariable != null) {
-                    typeVariable.setStateIfNotFixed(State.LOWER)
+                    typeVariable.setStateIfNotFixed(defaultStateProvider.defaultStateFor(typeVariable))
                     somethingChanged = true
                 }
             }
@@ -142,11 +144,11 @@ internal class Solver(
                 val (lower, upper) = constraint
                 if (lower is TypeVariableBound && lower.typeVariable.isFixed) {
                     somethingChanged = true
-                    constraint.subtype = lower.typeVariable.state.constraintBound
+                    constraint.subtype = lower.typeVariable.state.constraintBound()
                 }
                 if (upper is TypeVariableBound && upper.typeVariable.isFixed) {
                     somethingChanged = true
-                    constraint.supertype = upper.typeVariable.state.constraintBound
+                    constraint.supertype = upper.typeVariable.state.constraintBound()
                 }
             }
         }
@@ -166,14 +168,27 @@ internal class Solver(
         }
 
 
-    private fun List<Constraint>.getTypeVariableAsEqualsOrUpperBound(): TypeVariable? =
-        asSequence().filterIsInstance<SubtypeConstraint>()
-            .map { it.supertype }
-            .firstIsInstanceOrNull<TypeVariableBound>()
-            ?.typeVariable
-            ?: asSequence().filterIsInstance<EqualsConstraint>()
-                .flatMap { sequenceOf(it.left, it.right) }
-                .firstIsInstanceOrNull<TypeVariableBound>()
-                ?.typeVariable
+    private fun List<Constraint>.getTypeVariableAsEqualsOrUpperBound(): TypeVariable? {
+        for (constraint in this) {
+            when (constraint) {
+                is SubtypeConstraint -> {
+                    constraint.supertype.safeAs<TypeVariableBound>()
+                        ?.typeVariable
+                        ?.takeIf { defaultStateProvider.defaultStateFor(it) == State.LOWER }
+                        ?.let { return it }
+                    constraint.subtype.safeAs<TypeVariableBound>()
+                        ?.typeVariable
+                        ?.takeIf { defaultStateProvider.defaultStateFor(it) == State.UPPER }
+                        ?.let { return it }
+                }
+                is EqualsConstraint -> {
+                    (constraint.left.safeAs<TypeVariableBound>()
+                        ?: constraint.right.safeAs())
+                        ?.let { return it.typeVariable }
+                }
+            }
+        }
+        return null
+    }
 }
 

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/StateUpdater.kt

@@ -5,6 +5,23 @@
 
 package org.jetbrains.kotlin.nj2k.inference.common
 
+import org.jetbrains.kotlin.psi.psiUtil.isAncestor
+
 abstract class StateUpdater {
-    abstract fun updateStates(inferenceContext: InferenceContext)
+    fun updateStates(inferenceContext: InferenceContext) {
+        if (inferenceContext.typeVariables.isEmpty()) return
+
+        val deepComparator = Comparator<TypeElementBasedTypeVariable> { o1, o2 ->
+            if (o1.typeElement.typeElement.isAncestor(o2.typeElement.typeElement)) 1 else -1
+        }
+        for (typeVariable in inferenceContext
+            .typeVariables
+            .filterIsInstance<TypeElementBasedTypeVariable>()
+            .sortedWith(deepComparator)
+        ) {
+            typeVariable.updateState()
+        }
+    }
+
+    abstract fun TypeElementBasedTypeVariable.updateState()
 }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/collectors/CallExpressionConstraintCollector.kt

@@ -96,10 +96,10 @@ class CallExpressionConstraintCollector : ConstraintsCollector() {
                             BoundTypeImpl(
                                 GenericLabel(NoClassReference),//not important as it just a primitive type
                                 emptyList()
-                            ) else parameterBoundType.typeParameters[0].boundType
+                            ) else parameterBoundType.typeParameters.getOrNull(0)?.boundType
                     } else parameterBoundType
-                arguments.arguments.map { argument ->
-                    parameterBoundTypeConsideringVararg to argument
+                arguments.arguments.mapNotNull { argument ->
+                    parameterBoundTypeConsideringVararg?.let { it to argument }
                 }
             }
         }.flatten()

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/typeVariables.kt

@@ -6,81 +6,61 @@
 package org.jetbrains.kotlin.nj2k.inference.common
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.idea.refactoring.isAbstract
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.psi.psiUtil.isPrivate
 import org.jetbrains.kotlin.types.KotlinType
 
 sealed class TypeVariable {
     abstract val classReference: ClassReference
     abstract val typeParameters: List<TypeParameter>
+    abstract val owner: TypeVariableOwner
     abstract var state: State
 }
 
+sealed class TypeVariableOwner
+
+class FunctionParameter(val owner: KtFunction) : TypeVariableOwner()
+class FunctionReturnType(val function: KtFunction) : TypeVariableOwner()
+class Property(val property: KtProperty) : TypeVariableOwner()
+object TypeArgument : TypeVariableOwner()
+object OtherTarget : TypeVariableOwner()
+
+
 sealed class TypeElementData {
     abstract val typeElement: KtTypeElement
+    abstract val type: KotlinType
 }
 
-data class TypeElementDataImpl(override val typeElement: KtTypeElement) : TypeElementData()
+data class TypeElementDataImpl(
+    override val typeElement: KtTypeElement,
+    override val type: KotlinType
+) : TypeElementData()
+
 data class TypeParameterElementData(
     override val typeElement: KtTypeElement,
+    override val type: KotlinType,
     val typeParameterDescriptor: TypeParameterDescriptor
 ) : TypeElementData()
 
-data class TypeElementBasedTypeVariable(
+class TypeElementBasedTypeVariable(
     override val classReference: ClassReference,
     override val typeParameters: List<TypeParameter>,
     val typeElement: TypeElementData,
+    override val owner: TypeVariableOwner,
     override var state: State
-) : TypeVariable() {
+) : TypeVariable()
 
-    //ignore state as it is mutable
-    override fun equals(other: Any?): Boolean {
-        if (this === other) return true
-        if (javaClass != other?.javaClass) return false
-
-        other as TypeElementBasedTypeVariable
-
-        if (classReference != other.classReference) return false
-        if (typeParameters != other.typeParameters) return false
-        if (typeElement != other.typeElement) return false
-
-        return true
-    }
-
-    override fun hashCode(): Int {
-        var result = classReference.hashCode()
-        result = 31 * result + typeParameters.hashCode()
-        result = 31 * result + typeElement.hashCode()
-        return result
-    }
-}
-
-data class TypeBasedTypeVariable(
+class TypeBasedTypeVariable(
     override val classReference: ClassReference,
     override val typeParameters: List<TypeParameter>,
     val type: KotlinType,
     override var state: State
 ) : TypeVariable() {
-
-    //ignore state as it is mutable
-    override fun equals(other: Any?): Boolean {
-        if (this === other) return true
-        if (javaClass != other?.javaClass) return false
-
-        other as TypeBasedTypeVariable
-
-        if (classReference != other.classReference) return false
-        if (typeParameters != other.typeParameters) return false
-        if (type != other.type) return false
-
-        return true
-    }
-
-    override fun hashCode(): Int {
-        var result = classReference.hashCode()
-        result = 31 * result + typeParameters.hashCode()
-        result = 31 * result + type.hashCode()
-        return result
-    }
+    override val owner = OtherTarget
 }
 
 val TypeVariable.isFixed: Boolean

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/utils.kt

@@ -7,11 +7,14 @@ package org.jetbrains.kotlin.nj2k.inference.common
 
 import com.intellij.psi.PsiComment
 import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.nj2k.JKElementInfo
-import org.jetbrains.kotlin.nj2k.JKElementInfoLabel
-import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
-import org.jetbrains.kotlin.nj2k.asLabel
+import org.jetbrains.kotlin.idea.refactoring.isInterfaceClass
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.nj2k.*
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtTypeElement
 import org.jetbrains.kotlin.psi.KtTypeProjection
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 fun PsiElement.getLabel(): JKElementInfoLabel? =
@@ -28,3 +31,14 @@ fun PsiElement.elementInfo(converterContext: NewJ2kConverterContext): List<JKEle
     getLabel()?.let { label ->
         converterContext.elementsInfoStorage.getInfoForLabel(label)
     }
+
+
+private fun KtTypeReference.hasUnknownLabel(context: NewJ2kConverterContext, unknownLabel: JKElementInfo) =
+    getLabel()?.let { label ->
+        unknownLabel in context.elementsInfoStorage.getInfoForLabel(label).orEmpty()
+    } ?: false
+
+fun KtTypeElement.hasUnknownLabel(context: NewJ2kConverterContext, unknownLabel: JKElementInfo) =
+    parent
+        ?.safeAs<KtTypeReference>()
+        ?.hasUnknownLabel(context, unknownLabel) == true

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/nullability/NullabilityConstraintBoundProvider.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.nj2k.inference.nullability
+
+import org.jetbrains.kotlin.nj2k.inference.common.*
+
+class NullabilityConstraintBoundProvider : ConstraintBoundProviderImpl() {
+    override fun BoundTypeLabel.constraintBound(): ConstraintBound? = when (this) {
+        is TypeVariableLabel -> typeVariable.constraintBound()
+        is TypeParameterLabel -> null
+        is GenericLabel -> null
+        StarProjectionLabel -> null
+        NullLiteralLabel -> LiteralBound.UPPER
+        LiteralLabel -> LiteralBound.LOWER
+    }
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/nullability/NullabilityConstraintsCollector.kt

@@ -17,7 +17,7 @@ class NullabilityConstraintsCollector : ConstraintsCollector() {
         boundTypeCalculator: BoundTypeCalculator,
         inferenceContext: InferenceContext,
         resolutionFacade: ResolutionFacade
-    ) = with(boundTypeCalculator) {
+    ) {
         when {
             element is KtBinaryExpression &&
                     (element.left?.isNullExpression() == true
@@ -50,6 +50,5 @@ class NullabilityConstraintsCollector : ConstraintsCollector() {
                 element.right?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
             }
         }
-        Unit
     }
 }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/nullability/NullabilityContextCollector.kt

@@ -8,10 +8,7 @@ package org.jetbrains.kotlin.nj2k.inference.nullability
 import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
 import org.jetbrains.kotlin.nj2k.UnknownNullability
-import org.jetbrains.kotlin.nj2k.inference.common.ClassReference
-import org.jetbrains.kotlin.nj2k.inference.common.ContextCollector
-import org.jetbrains.kotlin.nj2k.inference.common.State
-import org.jetbrains.kotlin.nj2k.inference.common.getLabel
+import org.jetbrains.kotlin.nj2k.inference.common.*
 import org.jetbrains.kotlin.psi.KtNullableType
 import org.jetbrains.kotlin.psi.KtTypeElement
 import org.jetbrains.kotlin.psi.KtTypeReference
@@ -21,23 +18,10 @@ class NullabilityContextCollector(
     resolutionFacade: ResolutionFacade,
     private val converterContext: NewJ2kConverterContext
 ) : ContextCollector(resolutionFacade) {
-    override fun ClassReference.getState(typeElement: KtTypeElement?): State? {
-        val hasUndefinedNullabilityLabel = typeElement
-            ?.parent
-            ?.safeAs<KtTypeReference>()
-            ?.hasUndefinedNullabilityLabel(converterContext)
-            ?: false
-        return when {
-            typeElement == null -> State.UNKNOWN
-            hasUndefinedNullabilityLabel -> State.UNKNOWN
-            typeElement is KtNullableType -> State.UPPER
-            else -> State.LOWER
-        }
+    override fun ClassReference.getState(typeElement: KtTypeElement?): State? = when {
+        typeElement == null -> State.UNKNOWN
+        typeElement.hasUnknownLabel(converterContext, UnknownNullability) -> State.UNKNOWN
+        typeElement is KtNullableType -> State.UPPER
+        else -> State.LOWER
     }
-
-
-    private fun KtTypeReference.hasUndefinedNullabilityLabel(context: NewJ2kConverterContext) =
-        getLabel()?.let { label ->
-            context.elementsInfoStorage.getInfoForLabel(label).orEmpty().contains(UnknownNullability)
-        } ?: false
 }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/nullability/NullabilityDefaultStateProvider.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.nj2k.inference.nullability
+
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.idea.refactoring.isAbstract
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.nj2k.inference.common.*
+import org.jetbrains.kotlin.psi.psiUtil.isPrivate
+
+class NullabilityDefaultStateProvider : DefaultStateProvider() {
+    override fun defaultStateFor(typeVariable: TypeVariable): State {
+        if (typeVariable is TypeElementBasedTypeVariable
+            && typeVariable.typeElement.type.constructor.declarationDescriptor is TypeParameterDescriptor
+        ) {
+            return State.LOWER
+        }
+        return when (val owner = typeVariable.owner) {
+            is FunctionParameter -> if (owner.owner.isPrivate()) State.LOWER else State.UPPER
+            is FunctionReturnType ->
+                if (owner.function.isAbstract()
+                    || owner.function.hasModifier(KtTokens.OPEN_KEYWORD)
+                    || owner.function.bodyExpression == null
+                ) State.UPPER else State.LOWER
+            is Property -> if (owner.property.isPrivate()
+                || !owner.property.isVar
+                || !owner.property.isLocal
+            ) State.LOWER else State.UPPER
+            is TypeArgument -> State.LOWER
+            OtherTarget -> State.UPPER
+        }
+    }
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/nullability/NullabilityStateUpdater.kt

@@ -12,27 +12,14 @@ import org.jetbrains.kotlin.psi.KtTypeElement
 import org.jetbrains.kotlin.psi.psiUtil.isAncestor
 
 class NullabilityStateUpdater : StateUpdater() {
-    override fun updateStates(inferenceContext: InferenceContext) {
-        if (inferenceContext.typeVariables.isEmpty()) return
-
-        val deepComparator = Comparator<TypeElementBasedTypeVariable> { o1, o2 ->
-            if (o1.typeElement.typeElement.isAncestor(o2.typeElement.typeElement)) 1 else -1
-        }
-        for (typeVariable in inferenceContext
-            .typeVariables
-            .filterIsInstance<TypeElementBasedTypeVariable>()
-            .sortedWith(deepComparator)
-        ) {
-            when (typeVariable.state) {
-                State.LOWER -> typeVariable.changeState(toNullable = false)
-                State.UPPER -> typeVariable.changeState(toNullable = true)
-                State.UNKNOWN -> {
-                    if (typeVariable.typeElement is TypeParameterElementData) {
-                        typeVariable.changeState(toNullable = false)
-                    } else {
-                        typeVariable.changeState(toNullable = true)
-                    }
-                }
+    override fun TypeElementBasedTypeVariable.updateState() = when (state) {
+        State.LOWER -> changeState(toNullable = false)
+        State.UPPER -> changeState(toNullable = true)
+        State.UNKNOWN -> {
+            if (typeElement is TypeParameterElementData) {
+                changeState(toNullable = false)
+            } else {
+                changeState(toNullable = true)
             }
         }
     }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/J2kPostProcessor.kt

@@ -238,6 +238,13 @@ private val processings: List<NamedPostProcessingGroup> = listOf(
     NamedPostProcessingGroup(
         "Inferring declarations nullability",
         listOf(
+            InspectionLikeProcessingGroup(
+                processings = listOf(
+                    VarToValProcessing(),
+                    generalInspectionBasedProcessing(CanBeValInspection(ignoreNotUsedVals = false))
+                ),
+                runSingleTime = true
+            ),
             nullabilityProcessing,
             clearUndefinedLabelsProcessing
         )

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/processings/ConvertGettersAndSettersToPropertyProcessing.kt

@@ -23,7 +23,9 @@ import org.jetbrains.kotlin.idea.references.KtSimpleNameReference
 import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.references.readWriteAccess
 import org.jetbrains.kotlin.idea.util.CommentSaver
-import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
+import org.jetbrains.kotlin.j2k.getContainingClass
+import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
 import org.jetbrains.kotlin.nj2k.asGetterName
@@ -35,8 +37,10 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperInterfaces
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
+import org.jetbrains.kotlin.types.isError
 import org.jetbrains.kotlin.types.typeUtil.isUnit
-import org.jetbrains.kotlin.types.typeUtil.makeNotNullable
 import org.jetbrains.kotlin.util.isJavaDescriptor
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
@@ -108,7 +112,6 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
         }
     }
 
-
     private fun KtElement.forAllUsages(action: (KtElement) -> Unit) {
         usages().forEach { action(it.element as KtElement) }
     }
@@ -129,13 +132,12 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
 
         val ktGetter = factory.createGetter(body, getter.modifiersText)
         ktGetter.filterModifiers()
-        return property.add(ktGetter).cast<KtPropertyAccessor>().let {
+        return property.add(ktGetter).cast<KtPropertyAccessor>().also {
             if (getter is RealGetter) {
                 getter.function.forAllUsages { usage ->
                     usage.getStrictParentOfType<KtCallExpression>()!!.replace(factory.createExpression(getter.name))
                 }
             }
-            it
         }
     }
 
@@ -270,9 +272,15 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
 
 
     override fun runProcessing(elements: List<PsiElement>, converterContext: NewJ2kConverterContext) {
-        val classes = elements.descendantsOfType<KtClassOrObject>().sortedByInheritance()
-        for (klass in classes) {
-            convertClass(klass)
+        val classes = elements
+            .descendantsOfType<KtClassOrObject>()
+            .sortedByInheritance()
+        val collectingState = CollectingState()
+        val classesWithPropertiesData = classes.map { klass ->
+            klass to klass.collectPropertiesData(collectingState)
+        }
+        for ((klass, propertiesData) in classesWithPropertiesData) {
+            convertClass(klass, propertiesData)
         }
     }
 
@@ -287,8 +295,82 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
             else -> false
         }
 
-    private fun KtClassOrObject.collectGettersAndSetters(factory: KtPsiFactory): List<PropertyWithAccessors> {
-        val classDescriptor = resolveToDescriptorIfAny() ?: return emptyList()
+    private fun calculatePropertyType(getterType: KotlinType?, setterType: KotlinType?): KotlinType? = when {
+        getterType != null && getterType.isMarkedNullable -> getterType
+        setterType != null && setterType.isMarkedNullable -> setterType
+        else -> getterType ?: setterType
+    }
+
+    private fun calculatePropertyType(getter: KtNamedFunction?, setter: KtNamedFunction?): KotlinType? {
+        val getterType = getter?.resolveToDescriptorIfAny()?.returnType
+        val setterType = setter?.resolveToDescriptorIfAny()?.valueParameters?.singleOrNull()?.type
+        return calculatePropertyType(getterType, setterType)
+    }
+
+    private fun calculatePropertyTypeBasedOnSuperDescriptors(getter: KtNamedFunction?, setter: KtNamedFunction?): KotlinType? {
+        val superGetterType = getter
+            ?.resolveToDescriptorIfAny()
+            ?.overriddenDescriptors
+            ?.firstOrNull()
+            ?.returnType
+        val superSetterType = setter
+            ?.resolveToDescriptorIfAny()
+            ?.overriddenDescriptors
+            ?.firstOrNull()
+            ?.valueParameters
+            ?.singleOrNull()
+            ?.type
+        return calculatePropertyType(superGetterType, superSetterType)
+    }
+
+    private fun KtClassOrObject.collectPropertiesData(collectingState: CollectingState): List<PropertyData> {
+        return declarations
+            .asSequence()
+            .mapNotNull { it.asPropertyAccessor() }
+            .groupBy { it.name.removePrefix("is").decapitalize() }
+            .values
+            .mapNotNull { group ->
+                val realGetter = group.firstIsInstanceOrNull<RealGetter>()
+                val realSetter = group.firstIsInstanceOrNull<RealSetter>()?.takeIf { setter ->
+                    if (realGetter == null) return@takeIf true
+                    val setterType = setter.function.valueParameters.first().type()
+                    val getterType = realGetter.function.type()
+                    if (setterType == null
+                        || getterType == null
+                        || !KotlinTypeChecker.DEFAULT.isSubtypeOf(getterType, setterType)
+                    ) {
+                        if (isInterfaceClass()) return@mapNotNull null
+                        false
+                    } else true
+                }
+                if (realGetter == null && realSetter == null) return@mapNotNull null
+                val realProperty = group.firstIsInstanceOrNull<RealProperty>()
+                val name = realGetter?.name ?: realSetter?.name!!
+
+                val superDeclarationOwner = (realGetter?.function ?: realSetter?.function)
+                    ?.resolveToDescriptorIfAny()
+                    ?.overriddenDescriptors
+                    ?.firstOrNull()
+                    ?.findPsi()
+                    ?.safeAs<KtDeclaration>()
+                    ?.containingClassOrObject
+
+                collectingState.propertyNameToSuperType[superDeclarationOwner to name]
+                val type = collectingState.propertyNameToSuperType[superDeclarationOwner to name]
+                    ?: calculatePropertyType(
+                        realGetter?.function,
+                        realSetter?.function
+                    ) ?: return@mapNotNull null
+                collectingState.propertyNameToSuperType[this to name] = type
+                PropertyData(realProperty, realGetter, realSetter, type)
+            }
+    }
+
+    private fun List<PropertyData>.filterGettersAndSetters(
+        klass: KtClassOrObject,
+        factory: KtPsiFactory
+    ): List<PropertyWithAccessors> {
+        val classDescriptor = klass.resolveToDescriptorIfAny() ?: return emptyList()
 
         val variablesDescriptorsMap =
             (listOfNotNull(classDescriptor.getSuperClassNotAny()) + classDescriptor.getSuperInterfaces())
@@ -301,153 +383,135 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
                 .filterIsInstance<VariableDescriptor>()
                 .associateBy { it.name.asString() }
 
-        return declarations
-            .asSequence()
-            .mapNotNull { it.asPropertyAccessor() }
-            .groupBy { it.name.removePrefix("is").decapitalize() }
-            .values
-            .mapNotNull { group ->
-                val realGetter = group.firstIsInstanceOrNull<RealGetter>()
-                val realSetter = group.firstIsInstanceOrNull<RealSetter>()?.takeIf { setter ->
-                    if (realGetter == null) return@takeIf true
-                    if (setter.function.valueParameters.first().type()?.makeNotNullable() !=
-                        realGetter.function.type()?.makeNotNullable()
-                    ) {
-                        if (isInterfaceClass()) return@mapNotNull null
-                        false
-                    } else true
-                }
-                val realProperty = group.firstIsInstanceOrNull<RealProperty>()
-                if (realGetter == null && realSetter == null) return@mapNotNull null
-                val name = realGetter?.name ?: realSetter!!.name
-                val type =
-                    realGetter?.function?.typeReference?.text
-                        ?: realSetter?.function?.valueParameters?.first()?.typeReference?.text!!
+        return mapNotNull { (realProperty, realGetter, realSetter, type) ->
+            val name = realGetter?.name ?: realSetter!!.name
+            val typeStringified = type
+                .takeUnless { it.isError }
+                ?.let {
+                    IdeDescriptorRenderers.SOURCE_CODE.renderType(it)
+                } ?: realGetter?.function?.typeReference?.text
+            ?: realSetter?.function?.valueParameters?.firstOrNull()?.typeReference?.text!!
 
-                if (realSetter != null
-                    && realGetter != null
-                    && isInterfaceClass()
-                    && realSetter.function.hasOverrides() != realGetter.function.hasOverrides()
+            if (realSetter != null
+                && realGetter != null
+                && klass.isInterfaceClass()
+                && realSetter.function.hasOverrides() != realGetter.function.hasOverrides()
+            ) return@mapNotNull null
+
+            if (realSetter != null
+                && realGetter != null
+                && realSetter.function.hasSuperFunction() != realGetter.function.hasSuperFunction()
+            ) return@mapNotNull null
+
+            if (realProperty != null
+                && realGetter?.target != null
+                && realGetter.target != realProperty.property
+                && realProperty.property.hasInitializer()
+            ) return@mapNotNull null
+
+            if (realGetter?.function?.hasInvalidSuperDescriptors() == true
+                || realSetter?.function?.hasInvalidSuperDescriptors() == true
+            ) return@mapNotNull null
+
+            if (realProperty == null) {
+                if (causesNameConflictInCurrentDeclarationAndItsParents(
+                        name,
+                        classDescriptor.containingDeclaration
+                    )
                 ) return@mapNotNull null
-
-                if (realSetter != null
-                    && realGetter != null
-                    && realSetter.function.hasSuperFunction() != realGetter.function.hasSuperFunction()
-                ) return@mapNotNull null
-
-                if (realProperty != null
-                    && realGetter?.target != null
-                    && realGetter.target != realProperty.property
-                    && realProperty.property.hasInitializer()
-                ) return@mapNotNull null
-
-
-
-                if (realGetter?.function?.hasInvalidSuperDescriptors() == true
-                    || realSetter?.function?.hasInvalidSuperDescriptors() == true
-                ) return@mapNotNull null
-
-                if (realProperty == null) {
-                    if (causesNameConflictInCurrentDeclarationAndItsParents(
-                            name,
-                            classDescriptor.containingDeclaration
-                        )
-                    ) return@mapNotNull null
-                }
-
-                if (realProperty != null && (realGetter != null && realGetter.target == null || realSetter != null && realSetter.target == null)) {
-                    if (!realProperty.property.isPrivate()) return@mapNotNull null
-                    val hasUsages =
-                        realProperty.property.hasUsagesOutsideOf(
-                            containingKtFile,
-                            listOfNotNull(realGetter?.function, realSetter?.function)
-                        )
-                    if (hasUsages) return@mapNotNull null
-                }
-
-                if (realSetter != null && realProperty != null) {
-                    val assignFieldOfOtherInstance = realProperty.property.usages().any { usage ->
-                        val element = usage.safeAs<KtSimpleNameReference>()?.element ?: return@any false
-                        if (!element.readWriteAccess(useResolveForReadWrite = true).isWrite) return@any false
-                        val parent = element.parent
-                        parent is KtQualifiedExpression && !parent.receiverExpression.isReferenceToThis()
-                    }
-                    if (assignFieldOfOtherInstance) return@mapNotNull null
-                }
-
-
-                if (realGetter != null && realProperty != null) {
-                    val getFieldOfOtherInstanceInGetter = realProperty.property.usages().any { usage ->
-                        val element = usage.safeAs<KtSimpleNameReference>()?.element ?: return@any false
-                        val parent = element.parent
-                        parent is KtQualifiedExpression
-                                && !parent.receiverExpression.isReferenceToThis()
-                                && realGetter.function.isAncestor(element)
-                    }
-                    if (getFieldOfOtherInstanceInGetter) return@mapNotNull null
-                }
-
-
-                val getter = realGetter ?: when {
-                    realProperty?.property?.resolveToDescriptorIfAny()?.overriddenDescriptors?.any {
-                        it.safeAs<VariableDescriptor>()?.isVar == true
-                    } == true -> FakeGetter(name, null, "")
-
-                    variablesDescriptorsMap[name]?.let { variable ->
-                        variable.isVar && variable.containingDeclaration != classDescriptor
-                    } == true ->
-                        FakeGetter(name, factory.createExpression("super.$name"), "")
-
-                    else -> return@mapNotNull null
-                }
-
-                val mergedProperty =
-                    if (getter is RealGetter
-                        && getter.target != null
-                        && getter.target!!.name != getter.name
-                        && (realSetter == null || realSetter.target != null)
-                    ) {
-                        MergedProperty(name, type, realSetter != null, getter.target!!)
-                    } else null
-
-                val setter = realSetter ?: when {
-                    realProperty?.property?.isVar == true ->
-                        FakeSetter(name, null, "")
-
-                    realProperty?.property?.resolveToDescriptorIfAny()?.overriddenDescriptors?.any {
-                        it.safeAs<VariableDescriptor>()?.isVar == true
-                    } == true
-                            || variablesDescriptorsMap[name]?.isVar == true ->
-                        FakeSetter(
-                            name,
-                            factory.createBlock("super.$name = $name"),
-                            ""
-                        )
-
-                    realGetter != null
-                            && (realProperty != null
-                            && realProperty.property.visibilityModifierTypeOrDefault() != realGetter.function.visibilityModifierTypeOrDefault()
-                            && realProperty.property.isVar
-                            || mergedProperty != null
-                            && mergedProperty.mergeTo.visibilityModifierTypeOrDefault() != realGetter.function.visibilityModifierTypeOrDefault()
-                            && mergedProperty.mergeTo.isVar
-                            ) ->
-                        FakeSetter(name, null, null)
-
-                    else -> null
-                }
-                val isVar = setter != null
-
-                val property = mergedProperty?.copy(isVar = isVar)
-                    ?: realProperty?.copy(isVar = isVar)
-                    ?: FakeProperty(name, type, isVar)
-
-                PropertyWithAccessors(
-                    property,
-                    getter,
-                    setter
-                )
             }
+
+            if (realProperty != null && (realGetter != null && realGetter.target == null || realSetter != null && realSetter.target == null)) {
+                if (!realProperty.property.isPrivate()) return@mapNotNull null
+                val hasUsages =
+                    realProperty.property.hasUsagesOutsideOf(
+                        klass.containingKtFile,
+                        listOfNotNull(realGetter?.function, realSetter?.function)
+                    )
+                if (hasUsages) return@mapNotNull null
+            }
+
+            if (realSetter != null && realProperty != null) {
+                val assignFieldOfOtherInstance = realProperty.property.usages().any { usage ->
+                    val element = usage.safeAs<KtSimpleNameReference>()?.element ?: return@any false
+                    if (!element.readWriteAccess(useResolveForReadWrite = true).isWrite) return@any false
+                    val parent = element.parent
+                    parent is KtQualifiedExpression && !parent.receiverExpression.isReferenceToThis()
+                }
+                if (assignFieldOfOtherInstance) return@mapNotNull null
+            }
+
+            if (realGetter != null && realProperty != null) {
+                val getFieldOfOtherInstanceInGetter = realProperty.property.usages().any { usage ->
+                    val element = usage.safeAs<KtSimpleNameReference>()?.element ?: return@any false
+                    val parent = element.parent
+                    parent is KtQualifiedExpression
+                            && !parent.receiverExpression.isReferenceToThis()
+                            && realGetter.function.isAncestor(element)
+                }
+                if (getFieldOfOtherInstanceInGetter) return@mapNotNull null
+            }
+
+
+            val getter = realGetter ?: when {
+                realProperty?.property?.resolveToDescriptorIfAny()?.overriddenDescriptors?.any {
+                    it.safeAs<VariableDescriptor>()?.isVar == true
+                } == true -> FakeGetter(name, null, "")
+
+                variablesDescriptorsMap[name]?.let { variable ->
+                    variable.isVar && variable.containingDeclaration != classDescriptor
+                } == true ->
+                    FakeGetter(name, factory.createExpression("super.$name"), "")
+
+                else -> return@mapNotNull null
+            }
+
+            val mergedProperty =
+                if (getter is RealGetter
+                    && getter.target != null
+                    && getter.target!!.name != getter.name
+                    && (realSetter == null || realSetter.target != null)
+                ) {
+                    MergedProperty(name, typeStringified, realSetter != null, getter.target!!)
+                } else null
+
+            val setter = realSetter ?: when {
+                realProperty?.property?.isVar == true ->
+                    FakeSetter(name, null, "")
+
+                realProperty?.property?.resolveToDescriptorIfAny()?.overriddenDescriptors?.any {
+                    it.safeAs<VariableDescriptor>()?.isVar == true
+                } == true
+                        || variablesDescriptorsMap[name]?.isVar == true ->
+                    FakeSetter(
+                        name,
+                        factory.createBlock("super.$name = $name"),
+                        ""
+                    )
+
+                realGetter != null
+                        && (realProperty != null
+                        && realProperty.property.visibilityModifierTypeOrDefault() != realGetter.function.visibilityModifierTypeOrDefault()
+                        && realProperty.property.isVar
+                        || mergedProperty != null
+                        && mergedProperty.mergeTo.visibilityModifierTypeOrDefault() != realGetter.function.visibilityModifierTypeOrDefault()
+                        && mergedProperty.mergeTo.isVar
+                        ) ->
+                    FakeSetter(name, null, null)
+
+                else -> null
+            }
+            val isVar = setter != null
+            val property = mergedProperty?.copy(isVar = isVar)
+                ?: realProperty?.copy(isVar = isVar)
+                ?: FakeProperty(name, typeStringified, isVar)
+
+            PropertyWithAccessors(
+                property,
+                getter,
+                setter
+            )
+        }
     }
 
     private fun KtProperty.renameTo(newName: String, factory: KtPsiFactory) {
@@ -466,9 +530,10 @@ class ConvertGettersAndSettersToPropertyProcessing : ElementsBasedPostProcessing
         setName(newName)
     }
 
-    private fun convertClass(klass: KtClassOrObject) {
+    private fun convertClass(klass: KtClassOrObject, propertiesData: List<PropertyData>) {
         val factory = KtPsiFactory(klass)
-        val accessors = klass.collectGettersAndSetters(factory)
+        val accessors = propertiesData.filterGettersAndSetters(klass, factory)
+
         for ((property, getter, setter) in accessors) {
             val ktProperty = when (property) {
                 is RealProperty -> {
@@ -537,6 +602,13 @@ private data class PropertyWithAccessors(
     val setter: Setter?
 )
 
+private data class PropertyData(
+    val realProperty: RealProperty?,
+    val realGetter: RealGetter?,
+    val realSetter: RealSetter?,
+    val type: KotlinType
+)
+
 private interface PropertyInfo {
     val name: String
 }
@@ -618,6 +690,10 @@ private data class FakeSetter(
         get() = name.fixSetterParameterName()
 }
 
+private data class CollectingState(
+    val propertyNameToSuperType: MutableMap<Pair<KtClassOrObject, String>, KotlinType> = mutableMapOf()
+)
+
 private fun String.fixSetterParameterName() =
     if (this == KtTokens.FIELD_KEYWORD.value) "value"
     else this

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/processings/ConvertToDataClassProcessing.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.asAssignment
 import org.jetbrains.kotlin.psi.psiUtil.containingClass
 import org.jetbrains.kotlin.psi.psiUtil.visibilityModifierTypeOrDefault
+import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class ConvertToDataClassProcessing : ElementsBasedPostProcessing() {
@@ -64,7 +65,7 @@ class ConvertToDataClassProcessing : ElementsBasedPostProcessing() {
                             } ?: return@map null
                         val propertyType = property.type() ?: return@map null
                         val parameterType = parameter.type() ?: return@map null
-                        if (propertyType != parameterType) return@map null
+                        if (!KotlinTypeChecker.DEFAULT.equalTypes(propertyType, parameterType)) return@map null
                         parametersUsed += parameter
                         ConstructorParameterInitialization(property, parameter, assignment)
                     }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/processings/inspeсtionLikeProcessings.kt

@@ -40,6 +40,7 @@ import org.jetbrains.kotlin.nj2k.postProcessing.resolve
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.types.isNullable
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
@@ -55,8 +56,8 @@ class RemoveExplicitPropertyTypeProcessing : ApplicabilityBasedInspectionLikePro
         val initializer = element.initializer ?: return false
         val withoutExpectedType =
             initializer.analyzeInContext(initializer.getResolutionScope()).getType(initializer) ?: return false
-        val descriptor = element.resolveToDescriptorIfAny() as? CallableDescriptor ?: return false
-        return withoutExpectedType == descriptor.returnType
+        val typeBeDescriptor = element.resolveToDescriptorIfAny().safeAs<CallableDescriptor>()?.returnType ?: return false
+        return KotlinTypeChecker.DEFAULT.equalTypes(withoutExpectedType, typeBeDescriptor)
     }
 
     override fun apply(element: KtProperty) {

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/postProcessing/processings/processings.kt

@@ -54,6 +54,7 @@ val nullabilityProcessing =
             NullabilityContextCollector(resolutionFacade, converterContext),
             ConstraintsCollectorAggregator(
                 resolutionFacade,
+                NullabilityConstraintBoundProvider(),
                 listOf(
                     CommonConstraintsCollector(),
                     CallExpressionConstraintCollector(),
@@ -62,7 +63,8 @@ val nullabilityProcessing =
                 )
             ),
             BoundTypeCalculatorImpl(resolutionFacade, NullabilityBoundTypeEnhancer(resolutionFacade)),
-            NullabilityStateUpdater()
+            NullabilityStateUpdater(),
+            NullabilityDefaultStateProvider()
         )
         val elements = if (rangeMarker != null) {
             file.elementsInRange(rangeMarker.range ?: return@postProcessing).filterIsInstance<KtElement>()

nj2k/src/org/jetbrains/kotlin/nj2k/JKElementInfoStorage.kt

@@ -14,9 +14,10 @@ sealed class SuperFunctionInfo
 data class ExternalSuperFunctionInfo(val descriptor: FunctionDescriptor) : SuperFunctionInfo()
 data class InternalSuperFunctionInfo(val label: JKElementInfoLabel) : SuperFunctionInfo()
 
-data class FunctionInfo(val originalDescriptor: FunctionDescriptor, val superFunctions: List<SuperFunctionInfo>) : JKElementInfo
+data class FunctionInfo(val superFunctions: List<SuperFunctionInfo>) : JKElementInfo
 
 object UnknownNullability : JKElementInfo
+object UnknownMutability : JKElementInfo
 
 inline class JKElementInfoLabel(val label: String) {
     fun render(): String = "/*@@$label@@*/"

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/AddElementsInfoConversion.kt

@@ -6,9 +6,14 @@
 package org.jetbrains.kotlin.nj2k.conversions
 
 import com.intellij.psi.PsiMethod
+import com.intellij.psi.impl.light.LightMethod
+import org.jetbrains.kotlin.asJava.elements.KtLightMethod
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.caches.resolve.util.getJavaMethodDescriptor
 import org.jetbrains.kotlin.j2k.ast.Nullability
 import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
+import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor
 import org.jetbrains.kotlin.nj2k.*
 import org.jetbrains.kotlin.nj2k.symbols.JKUniverseMethodSymbol
 import org.jetbrains.kotlin.nj2k.tree.*
@@ -20,7 +25,7 @@ class AddElementsInfoConversion(private val context: NewJ2kConverterContext) : R
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
         when (element) {
             is JKTypeElement -> addInfoForTypeElement(element)
-            is JKKtFunction -> addInfoForFunction(element)
+            is JKMethod -> addInfoForFunction(element)
         }
 
         return recurse(element)
@@ -33,24 +38,36 @@ class AddElementsInfoConversion(private val context: NewJ2kConverterContext) : R
             ) {
                 context.elementsInfoStorage.addEntry(type, UnknownNullability)
             }
+            if (type.isCollectionType) {
+                context.elementsInfoStorage.addEntry(type, UnknownMutability)
+            }
         }
     }
 
-    private fun addInfoForFunction(function: JKKtFunction) {
-        val psiMethod = function.psi<PsiMethod>() ?: return
-        val descriptor = psiMethod.getJavaMethodDescriptor() ?: return
-        val superDescriptorsInfo =
-            descriptor.overriddenDescriptors.mapNotNull { superDescriptor ->
-                val superPsi = superDescriptor.original.findPsi()
-                when (val symbol = context.symbolProvider.symbolsByPsi[superPsi]) {
-                    is JKUniverseMethodSymbol ->
-                        InternalSuperFunctionInfo(
-                            context.elementsInfoStorage.getOrCreateInfoForElement(symbol.target)
-                        )
-                    else -> ExternalSuperFunctionInfo(superDescriptor)
-                }
+    private fun addInfoForFunction(function: JKMethod) {
+        val superMethods = function.superMethods() ?: return
+        val superDescriptorsInfo = superMethods.map { superDescriptor ->
+            val superPsi = superDescriptor.original.findPsi()
+            when (val symbol = context.symbolProvider.symbolsByPsi[superPsi]) {
+                is JKUniverseMethodSymbol ->
+                    InternalSuperFunctionInfo(context.elementsInfoStorage.getOrCreateInfoForElement(symbol.target))
+                else -> ExternalSuperFunctionInfo(superDescriptor)
             }
-        context.elementsInfoStorage.addEntry(function, FunctionInfo(descriptor, superDescriptorsInfo))
+        }
+        context.elementsInfoStorage.addEntry(function, FunctionInfo(superDescriptorsInfo))
+    }
+
+    private fun JKMethod.superMethods(): Collection<FunctionDescriptor>? {
+        val psiMethod = psi<PsiMethod>() ?: return null
+        psiMethod.getJavaMethodDescriptor()?.let { descriptor ->
+            return descriptor.overriddenDescriptors
+        }
+        return psiMethod.findSuperMethods().mapNotNull { superMethod ->
+            when (superMethod) {
+                is KtLightMethod -> superMethod.kotlinOrigin?.resolveToDescriptorIfAny()?.safeAs()
+                else -> superMethod.getJavaMethodDescriptor()
+            }
+        }
     }
 
     private fun JKType.forAllInnerTypes(action: (JKType) -> Unit) {

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/StaticMemberAccessConversion.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.KtObjectDeclaration
 import org.jetbrains.kotlin.psi.psiUtil.containingClass
+import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
@@ -47,14 +48,13 @@ class StaticMemberAccessConversion(private val context: NewJ2kConverterContext)
             )
         }
         return recurse(element)
-
     }
 
     private fun JKSymbol.isStaticMember(): Boolean {
         val target = target
         return when (target) {
             is PsiModifierListOwner -> target.hasModifier(JvmModifier.STATIC)
-            is KtElement -> target.parentOfType<KtClassOrObject>()
+            is KtElement -> target.getStrictParentOfType<KtClassOrObject>()
                 ?.safeAs<KtObjectDeclaration>()
                 ?.isCompanion() == true
             is JKTreeElement ->

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/TypeMappingConversion.kt

@@ -22,17 +22,6 @@ import org.jetbrains.kotlin.nj2k.tree.*
 import org.jetbrains.kotlin.nj2k.tree.impl.*
 
 class TypeMappingConversion(val context: NewJ2kConverterContext) : RecursiveApplicableConversionBase() {
-    private val typeFlavorCalculator = TypeFlavorCalculator(object : TypeFlavorConverterFacade {
-        override val referenceSearcher: ReferenceSearcher
-            get() = context.converter.converterServices.oldServices.referenceSearcher
-        override val javaDataFlowAnalyzerFacade: JavaDataFlowAnalyzerFacade
-            get() = context.converter.converterServices.oldServices.javaDataFlowAnalyzerFacade
-        override val resolverForConverter: ResolverForConverter
-            get() = context.converter.converterServices.oldServices.resolverForConverter
-
-        override fun inConversionScope(element: PsiElement): Boolean = context.inConversionContext(element)
-    })
-
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
         return when (element) {
             is JKTypeElement -> {
@@ -62,8 +51,7 @@ class TypeMappingConversion(val context: NewJ2kConverterContext) : RecursiveAppl
                 }
             )
         }
-        val typeParametersCount = classSymbol.expectedTypeParametersCount()
-        return when (typeParametersCount) {
+        return when (val typeParametersCount = classSymbol.expectedTypeParametersCount()) {
             0 -> this
             else -> JKTypeArgumentListImpl(List(typeParametersCount) {
                 JKTypeElementImpl(
@@ -124,7 +112,7 @@ class TypeMappingConversion(val context: NewJ2kConverterContext) : RecursiveAppl
 
     private fun JKClassSymbol.mapClassSymbol(typeElement: JKTypeElement?): JKClassSymbol {
         if (this is JKUniverseClassSymbol) return this
-        val newFqName = typeElement?.let { kotlinCollectionClassName(it) }
+        val newFqName = kotlinCollectionClassName()
             ?: kotlinStandardType()
             ?: fqName
         return context.symbolProvider.provideClassSymbol(newFqName)
@@ -137,12 +125,8 @@ class TypeMappingConversion(val context: NewJ2kConverterContext) : RecursiveAppl
             nullability
         )
 
-
-    private fun JKClassSymbol.kotlinCollectionClassName(typeElement: JKTypeElement?): String? {
-        val isStructureMutable = calculateStructureMutability(typeElement)
-        return if (isStructureMutable) toKotlinMutableTypesMap[fqName]
-        else toKotlinTypesMap[fqName]
-    }
+    private fun JKClassSymbol.kotlinCollectionClassName(): String? =
+        toKotlinMutableTypesMap[fqName]
 
     private fun JKClassSymbol.kotlinStandardType(): String? {
         if (isKtFunction(fqName)) return fqName
@@ -157,16 +141,6 @@ class TypeMappingConversion(val context: NewJ2kConverterContext) : RecursiveAppl
         )
     }
 
-    private fun calculateStructureMutability(typeElement: JKTypeElement?): Boolean {
-        val parent = typeElement?.parent ?: return false
-        val psi = parent.psi ?: return false
-        return when (parent) {
-            is JKVariable -> typeFlavorCalculator.variableMutability(psi as PsiVariable) == Mutability.Mutable
-            is JKMethod -> typeFlavorCalculator.methodMutability(psi as PsiMethod) == Mutability.Mutable
-            else -> false
-        }
-    }
-
     companion object {
         private val ktFunctionRegex = "kotlin\\.jvm\\.functions\\.Function\\d+".toRegex()
         private fun isKtFunction(fqName: String) =

nj2k/src/org/jetbrains/kotlin/nj2k/tree/typesUtils.kt

@@ -357,11 +357,12 @@ fun JKType.arrayFqName(): String =
     else KotlinBuiltIns.FQ_NAMES.array.asString()
 
 fun JKClassSymbol.isArrayType(): Boolean =
-    fqName in
-            JKJavaPrimitiveTypeImpl.KEYWORD_TO_INSTANCE.values
-                .filterIsInstance<JKJavaPrimitiveType>()
-                .map { PrimitiveType.valueOf(it.jvmPrimitiveType.name).arrayTypeFqName.asString() } +
-            KotlinBuiltIns.FQ_NAMES.array.asString()
+    fqName in arrayFqNames
+
+private val arrayFqNames = JKJavaPrimitiveTypeImpl.KEYWORD_TO_INSTANCE.values
+    .filterIsInstance<JKJavaPrimitiveType>()
+    .map { PrimitiveType.valueOf(it.jvmPrimitiveType.name).arrayTypeFqName.asString() } +
+        KotlinBuiltIns.FQ_NAMES.array.asString()
 
 fun JKType.isArrayType() =
     when (this) {
@@ -370,6 +371,18 @@ fun JKType.isArrayType() =
         else -> false
     }
 
+val JKType.isCollectionType: Boolean
+    get() = safeAs<JKClassType>()?.classReference?.fqName in collectionFqNames
+
+private val collectionFqNames = setOf(
+    KotlinBuiltIns.FQ_NAMES.mutableIterator.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableList.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableCollection.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableSet.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableMap.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableMapEntry.asString(),
+    KotlinBuiltIns.FQ_NAMES.mutableListIterator.asString()
+)
 
 fun JKType.arrayInnerType(): JKType? =
     when (this) {

nj2k/src/org/jetbrains/kotlin/nj2k/utils.kt

@@ -32,6 +32,10 @@ fun String.asSetterName() =
         ?.decapitalize()
         ?.escaped()
 
+fun String.isPossiblyGetterOrSetterName() =
+    asGetterName() != null || asSetterName() != null
+
+
 private val KEYWORDS = KtTokens.KEYWORDS.types.map { (it as KtKeywordToken).value }.toSet()
 
 fun String.escaped() =

nj2k/testData/inference/nullability/arrayOfArraysOfNull.kt

@@ -1,6 +1,6 @@
 class Test {
     fun foo() {
-        val ss = Array</*T2@*/Array</*T1@*/String?>>(5/*LIT*/, { arrayOfNulls</*T0@*/String?>(5/*LIT*/)/*Array<T0@String!!U>!!L*/ }/*Function0<Int, T3@Array<T4@String>>!!L*/)
+        val ss = Array</*T2@*/Array</*T1@*/String?>>(5/*LIT*/, { arrayOfNulls</*T0@*/String>(5/*LIT*/)/*Array<T0@String!!U>!!L*/ }/*Function0<Int, T3@Array<T4@String>>!!L*/)
     }
 }
 

nj2k/testData/inference/nullability/arrayOfNulls.kt

@@ -1,5 +1,5 @@
 fun test() {
-    val x: /*T2@*/Array</*T1@*/Int?> = arrayOfNulls</*T0@*/Int?>(10/*LIT*/)/*Array<T0@Int!!U>!!L*/
+    val x: /*T2@*/Array</*T1@*/Int?> = arrayOfNulls</*T0@*/Int>(10/*LIT*/)/*Array<T0@Int!!U>!!L*/
 }
 
 //T1 := UPPER due to 'INITIALIZER'

nj2k/testData/inference/nullability/classTypeParameters.kt

@@ -1,5 +1,5 @@
 open class A<T> {
-    open fun foo(): /*T3@*/Map</*T0@*/T, /*T2@*/List</*T1@*/T>>? {
+    open fun foo(): /*T3@*/Map</*T0@*/T, /*T2@*/List</*T1@*/T>?>? {
         TODO()
     }
 
@@ -9,7 +9,7 @@ open class A<T> {
 }
 
 class B : A</*T10@*/Int>() {
-    override fun foo(): /*T8@*/Map</*T5@*/Int, /*T7@*/List</*T6@*/Int>>? {
+    override fun foo(): /*T8@*/Map</*T5@*/Int, /*T7@*/List</*T6@*/Int>?>? {
         return null/*NULL!!U*/
     }
     override fun bar(): /*T9@*/Int {

nj2k/testData/inference/nullability/forcedNullability.kt

@@ -1,4 +1,4 @@
-fun b(m: /*T2@*/Map</*T0@*/Int, /*T1@*/String>): /*T3@*/String? {
+fun b(m: /*T2@*/Map</*T0@*/Int?, /*T1@*/String?>): /*T3@*/String? {
     return m/*T2@Map<T0@Int, T1@String>*/.get(42/*LIT*/)/*T1@String!!U*/
 }
 

nj2k/testData/inference/nullability/functionTypeParameterNullability.kt

@@ -1,4 +1,4 @@
-fun <T, E, F, S> foo(x: /*T0@*/T, y: /*T2@*/List</*T1@*/E>, z: /*T4@*/List</*T3@*/F>, a: /*T5@*/S) {}
+fun <T, E, F, S> foo(x: /*T0@*/T, y: /*T2@*/List</*T1@*/E>?, z: /*T4@*/List</*T3@*/F>?, a: /*T5@*/S) {}
 
 fun bar() {
     val lst: /*T8@*/List</*T7@*/Int?> = listOf</*T6@*/Int?>(null/*NULL!!U*/)/*List<T6@Int>!!L*/

nj2k/testData/inference/nullability/functions.kt

@@ -1,6 +1,6 @@
-fun notNullParameters(f: /*T3@*/Function2</*T0@*/Int, /*T1@*/Int, /*T2@*/String>) {}
-fun nullableParameter(f: /*T7@*/Function2</*T4@*/Int?, /*T5@*/Int, /*T6@*/String>) {}
-fun nullableReturnType(f: /*T11@*/Function2</*T8@*/Int, /*T9@*/Int, /*T10@*/String?>) {}
+fun notNullParameters(f: /*T3@*/Function2</*T0@*/Int, /*T1@*/Int, /*T2@*/String?>?) {}
+fun nullableParameter(f: /*T7@*/Function2</*T4@*/Int?, /*T5@*/Int?, /*T6@*/String?>?) {}
+fun nullableReturnType(f: /*T11@*/Function2</*T8@*/Int, /*T9@*/Int?, /*T10@*/String?>?) {}
 
 
 fun test() {
@@ -8,11 +8,11 @@ fun test() {
                           if (i/*T12@Int*/ < 10/*LIT*//*LIT*/ && j/*T13@Int*/ > 0/*LIT*//*LIT*//*LIT*/) ""/*LIT*/ else ""/*LIT*/
                       }/*Function2<T12@Int, T13@Int, T18@String>!!L*/)
 
-    nullableParameter({ i: /*T14@*/Int?, j: /*T15@*/Int ->
+    nullableParameter({ i: /*T14@*/Int?, j: /*T15@*/Int? ->
                           if (i/*T14@Int*/ == null/*LIT*/) ""/*LIT*/ else ""/*LIT*/
                       }/*Function2<T14@Int, T15@Int, T19@String>!!L*/)
 
-    nullableReturnType({ i: /*T16@*/Int, j: /*T17@*/Int ->
+    nullableReturnType({ i: /*T16@*/Int, j: /*T17@*/Int? ->
                            if (i/*T16@Int*/ < 10/*LIT*//*LIT*/) return@nullableReturnType null/*NULL!!U*/
                            return@nullableReturnType "nya"/*LIT*/
                        }/*Function2<T16@Int, T17@Int, T20@String>!!L*/)

nj2k/testData/inference/nullability/javaStream.kt

@@ -7,7 +7,7 @@ import java.util.stream.Stream
 fun test(list: /*T1@*/List</*T0@*/String>) {
     val x: /*T9@*/List</*T8@*/String> = list/*T1@List<T0@String>*/.stream()/*Stream<T0@String>!!L*/
         .map</*T3@*/String>({ x: /*T2@*/String -> x/*T2@String*/ + ""/*LIT*//*LIT*/ }/*Function1<T2@String, T10@String>!!L*/)/*Stream<T3@String>*/
-        .collect</*T6@*/List</*T5@*/String>, /*T7@*/Any?>(Collectors/*LIT*/.toList</*T4@*/String>()/*Collector<T4@String, Any, MutableList<T4@String>>*/)/*T6@List<T5@String>*/
+        .collect</*T6@*/List</*T5@*/String>, /*T7@*/Any>(Collectors/*LIT*/.toList</*T4@*/String>()/*Collector<T4@String, Any, MutableList<T4@String>>*/)/*T6@List<T5@String>*/
 
 }
 

nj2k/testData/inference/nullability/lambdaReturnNull.kt

@@ -1,7 +1,7 @@
 class Test {
-    fun foo1(r: /*T2@*/Function1</*T0@*/Int, /*T1@*/String?>) {}
+    fun foo1(r: /*T2@*/Function1</*T0@*/Int, /*T1@*/String?>?) {}
     fun foo() {
-        foo1({ x: /*T3@*/Int -> ""/*LIT*/ }/*Function1<T3@Int, T5@String>!!L*/)
+        foo1({ x: /*T3@*/Int? -> ""/*LIT*/ }/*Function1<T3@Int, T5@String>!!L*/)
         foo1({ i: /*T4@*/Int ->
                  if (i/*T4@Int*/ > 1/*LIT*//*LIT*/) {
                      return@foo1 null/*NULL!!U*/

nj2k/testData/inference/nullability/loopIterator.kt

@@ -1,5 +1,5 @@
-fun test(a: /*T1@*/List</*T0@*/Int>) {
-    for (i: /*T2@*/Int in a/*T1@List<T0@Int>*/) {
+fun test(a: /*T1@*/List</*T0@*/Int?>) {
+    for (i: /*T2@*/Int? in a/*T1@List<T0@Int>*/) {
 
     }
 }

nj2k/testData/inference/nullability/loops.kt

@@ -1,4 +1,4 @@
-fun bar(map: /*T2@*/HashMap</*T0@*/String?, /*T1@*/Int>, list1: /*T4@*/List</*T3@*/Int>, list2: /*T6@*/List</*T5@*/String?>) {
+fun bar(map: /*T2@*/HashMap</*T0@*/String?, /*T1@*/Int>, list1: /*T4@*/List</*T3@*/Int?>, list2: /*T6@*/List</*T5@*/String?>) {
     for (entry: /*T9@*/MutableMap.MutableEntry</*T7@*/String?, /*T8@*/Int> in map/*T2@HashMap<T0@String, T1@Int>*/.entries/*MutableSet<MutableEntry<T0@String, T1@Int>>*/) {
         val value: /*T10@*/Int = entry/*T9@MutableEntry<T7@String, T8@Int>*/.value/*T8@Int*/
         if (entry/*T9@MutableEntry<T7@String, T8@Int>*/.key/*T7@String*/ == null/*LIT*/) {

nj2k/testData/inference/nullability/sequenceOfCallsWIthLambda.kt

@@ -1,7 +1,7 @@
 fun a(lst: /*T1@*/List</*T0@*/String>) {
     val newList: /*T8@*/List</*T7@*/Int> = lst/*T1@List<T0@String>*/
         .asSequence</*T2@*/String>()/*Sequence<T2@String>!!L*/
-        .map</*T4@*/String, /*T5@*/Int>({ x: /*T3@*/String -> 1/*LIT*/ }/*Function1<T3@String, T9@Int>!!L*/)/*Sequence<T5@Int>!!L*/
+        .map</*T4@*/String, /*T5@*/Int>({ x: /*T3@*/String? -> 1/*LIT*/ }/*Function1<T3@String, T9@Int>!!L*/)/*Sequence<T5@Int>!!L*/
         .toList</*T6@*/Int>()/*List<T6@Int>!!L*/
 }
 

nj2k/testData/inference/nullability/typeParametersReturnType.kt

@@ -1,5 +1,5 @@
 open class A<T> {
-    open fun foo(): /*T3@*/Map</*T0@*/T, /*T2@*/List</*T1@*/T>> {
+    open fun foo(): /*T3@*/Map</*T0@*/T, /*T2@*/List</*T1@*/T>?>? {
         TODO()
     }
 
@@ -9,7 +9,7 @@ open class A<T> {
 }
 
 class B : A</*T9@*/Int>() {
-    override fun foo(): /*T8@*/Map</*T5@*/Int, /*T7@*/List</*T6@*/Int>> {
+    override fun foo(): /*T8@*/Map</*T5@*/Int, /*T7@*/List</*T6@*/Int>?>? {
         TODO()
     }
 }

nj2k/testData/inference/nullability/typeParametersValueParams.kt

@@ -1,11 +1,11 @@
 open class A<T> {
-    open fun foo(x: /*T1@*/List</*T0@*/T>, y: /*T2@*/Boolean, z: /*T3@*/T) {
+    open fun foo(x: /*T1@*/List</*T0@*/T>?, y: /*T2@*/Boolean?, z: /*T3@*/T) {
         TODO()
     }
 }
 
-class B : A</*T8@*/Int>() {
-    override fun foo(x: /*T5@*/List</*T4@*/Int>, y: /*T6@*/Boolean, z: /*T7@*/Int) {
+class B : A</*T8@*/Int?>() {
+    override fun foo(x: /*T5@*/List</*T4@*/Int?>?, y: /*T6@*/Boolean?, z: /*T7@*/Int?) {
         TODO()
     }
 }

nj2k/testData/newJ2k/anonymousClass/kt-13146.kt

@@ -15,7 +15,7 @@ class Test2 {
 }
 
 class Handler {
-    fun postDelayed(r: Runnable, time: Long) {}
+    fun postDelayed(r: Runnable?, time: Long) {}
 }
 
 class Test3 {

nj2k/testData/newJ2k/arrayInitializerExpression/objectArrayWithLength.kt

@@ -1 +1 @@
-val a = arrayOfNulls<Any?>(10)
+val a = arrayOfNulls<Any>(10)

nj2k/testData/newJ2k/arrayType/arrayInitializationStatementWithDimension.kt

@@ -1 +1 @@
-val d2 = arrayOfNulls<IntArray?>(5)
+val d2 = arrayOfNulls<IntArray>(5)

nj2k/testData/newJ2k/arrayType/arrayInitializationStatementWithDimension3d.kt

@@ -1 +1 @@
-val d3 = Array(5) { arrayOfNulls<IntArray?>(5) }
+val d3 = Array(5) { arrayOfNulls<IntArray>(5) }

nj2k/testData/newJ2k/arrayType/d2StringEmptyArray.kt

@@ -1 +1 @@
-val ss = Array(5) { arrayOfNulls<String?>(5) }
+val ss = Array(5) { arrayOfNulls<String>(5) }

nj2k/testData/newJ2k/arrayType/d3StringEmptyArray.kt

@@ -1 +1 @@
-val sss = Array(5) { Array(5) { arrayOfNulls<String?>(5) } }
+val sss = Array(5) { Array(5) { arrayOfNulls<String>(5) } }

nj2k/testData/newJ2k/boxedType/kt-671.kt

@@ -1,6 +1,6 @@
 internal class Test {
     fun test() {
-        val i: Int? = Integer.valueOf(100)
+        val i = Integer.valueOf(100)
         val s: Short = 3
         val ss = s
     }

nj2k/testData/newJ2k/class/ClassShadowing.kt

@@ -1,8 +1,8 @@
 package test
 
-class Integer(s: String) {
+class Integer(s: String?) {
     companion object {
-        fun valueOf(value: String): Integer {
+        fun valueOf(value: String?): Integer {
             return Integer(value)
         }
     }

nj2k/testData/newJ2k/class/classWithEmptyMethods.kt

@@ -1,5 +1,5 @@
 internal class T {
     fun main() {}
     fun i(): Int {}
-    fun s(): String? {}
+    fun s(): String {}
 }

nj2k/testData/newJ2k/class/kt-639.kt

@@ -4,7 +4,7 @@ import java.util.HashMap
 
 internal class Test {
     constructor() {}
-    constructor(s: String) {}
+    constructor(s: String?) {}
 }
 
 internal class User {

nj2k/testData/newJ2k/constructors/fieldsInitializedFromParams8.kt

@@ -1,2 +1,2 @@
-internal open class Base(o: Any, l: Int)
+internal open class Base(o: Any?, l: Int)
 internal class C(private val string: String) : Base(string, string.length)

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults.kt

@@ -1,8 +1,6 @@
-internal class A @JvmOverloads constructor(nested: Nested = Nested(Nested.FIELD)) {
-
+internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
-
             const val FIELD = 0
         }
     }

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults2.kt

@@ -1,6 +1,6 @@
 import A.Nested
 
-internal class A @JvmOverloads constructor(nested: Nested = Nested(Nested.FIELD)) {
+internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
             const val FIELD = 0

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults3.kt

@@ -2,7 +2,7 @@ package pack
 
 import pack.A.Nested
 
-internal class A @JvmOverloads constructor(nested: Nested = Nested(Nested.FIELD)) {
+internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
             const val FIELD = 0

nj2k/testData/newJ2k/constructors/nestedClassNameInParameterDefaults4.kt

@@ -2,7 +2,7 @@ package pack
 
 import pack.A.Nested
 
-internal class A @JvmOverloads constructor(nested: Nested = Nested(Nested.FIELD)) {
+internal class A @JvmOverloads constructor(nested: Nested? = Nested(Nested.FIELD)) {
     internal class Nested(p: Int) {
         companion object {
             const val FIELD = 0

nj2k/testData/newJ2k/constructors/nestedClassNameInSuperParameters.kt

@@ -1,4 +1,4 @@
-internal open class Base(nested: Nested) {
+internal open class Base(nested: Nested?) {
     internal class Nested(p: Int) {
         companion object {
             const val FIELD = 0

nj2k/testData/newJ2k/constructors/withManyDefaultParams.kt

@@ -10,14 +10,12 @@ class Test {
     protected var g = 0.toChar()
 
     constructor() {}
-
-    constructor(name: String) {
+    constructor(name: String?) {
         myName = foo(name)
     }
 
     companion object {
-
-        internal fun foo(n: String): String {
+        internal fun foo(n: String?): String {
             return ""
         }
     }

nj2k/testData/newJ2k/equals/Equals3.kt

@@ -1,9 +1,9 @@
 internal class C {
-    fun equals(c: C): Boolean {
+    fun equals(c: C?): Boolean {
         return false
     }
 
-    fun foo(c1: C, c2: C): Boolean {
+    fun foo(c1: C, c2: C?): Boolean {
         return c1.equals(c2)
     }
 }

nj2k/testData/newJ2k/for/forThroughListIndices.kt

@@ -1,13 +1,13 @@
 import java.util.ArrayList
 
 internal class C {
-    fun foo1(list: MutableList<String>) {
+    fun foo1(list: MutableList<String?>) {
         for (i in list.indices) {
             list[i] = "a"
         }
     }
 
-    fun foo2(list: ArrayList<String>) {
+    fun foo2(list: ArrayList<String?>) {
         for (i in list.indices) {
             list[i] = "a"
         }

nj2k/testData/newJ2k/for/forThroughListIndicesNE.kt

@@ -1,5 +1,5 @@
 internal class C {
-    fun foo(list: MutableList<String>) {
+    fun foo(list: MutableList<String?>) {
         for (i in list.indices) {
             list[i] = "a"
         }

nj2k/testData/newJ2k/foreachStatement/nullableIterable.kt

@@ -1,5 +1,5 @@
 internal class A {
-    var list: List<String>? = null
+    var list: List<String?>? = null
     fun foo() {
         for (e in list!!) {
             println(e)

nj2k/testData/newJ2k/function/classGenericParam.kt

@@ -1,2 +1,2 @@
-val t: T?
+val t: T
     get() {}

nj2k/testData/newJ2k/function/externalKtFunctionalInterface.kt

@@ -11,6 +11,6 @@ internal class Test {
     fun nya(): Double {
         //TODO explicitlly call apply here
 
-        return foo(1, FunctionalI<Int?, Double?> { x: Int -> this.toDouble(x) })
+        return foo(1, FunctionalI<Int, Double> { x: Int -> this.toDouble(x) })
     }
 }

nj2k/testData/newJ2k/function/internalFunctionalInterface.kt

@@ -14,6 +14,6 @@ internal class Test {
     }
 
     fun nya(): Double {
-        return foo(1, FunctionalI<Int?, Double?> { x: A -> this.toDouble(x) })
+        return foo(1, FunctionalI<Int, Double> { x: A -> this.toDouble(x) })
     }
 }

nj2k/testData/newJ2k/function/java8Lambdas.kt

@@ -1,7 +1,7 @@
 class Java8Class {
-    fun foo0(r: Function0<String>) {}
-    fun foo1(r: Function1<Int, String?>) {}
-    fun foo2(r: Function2<Int, Int, String>) {}
+    fun foo0(r: Function0<String?>?) {}
+    fun foo1(r: Function1<Int, String?>?) {}
+    fun foo2(r: Function2<Int?, Int?, String?>?) {}
     fun helper() {}
     fun foo() {
         foo0 { "42" }
@@ -10,8 +10,8 @@ class Java8Class {
             helper()
             "42"
         }
-        foo1 { i: Int -> "42" }
-        foo1 { i: Int -> "42" }
+        foo1 { i: Int? -> "42" }
+        foo1 { i: Int? -> "42" }
         foo1 { i: Int ->
             helper()
             if (i > 1) {
@@ -19,12 +19,12 @@ class Java8Class {
             }
             "43"
         }
-        foo2 { i: Int, j: Int -> "42" }
-        foo2 { i: Int, j: Int ->
+        foo2 { i: Int?, j: Int? -> "42" }
+        foo2 { i: Int?, j: Int? ->
             helper()
             "42"
         }
-        val f = label@{ i: Int, k: Int ->
+        val f: Function2<Int, Int, String> = label@{ i: Int, k: Int? ->
             helper()
             if (i > 1) {
                 return@label "42"
@@ -32,7 +32,7 @@ class Java8Class {
             "43"
         }
         val f1 = label@{ i1: Int, k1: Int ->
-            val f2 = label@{ i2: Int, k2: Int ->
+            val f2: Function2<Int, Int, String> = label@{ i2: Int, k2: Int? ->
                 helper()
                 if (i2 > 1) {
                     return@label "42"

nj2k/testData/newJ2k/function/methodClassType.kt

@@ -1 +1 @@
-fun main(): String? {}
+fun main(): String {}

nj2k/testData/newJ2k/function/referenceToConstructor.kt

@@ -4,7 +4,7 @@ import java.util.stream.Collectors
 object TestLambda {
     @JvmStatic
     fun main(args: Array<String>) {
-        val names: List<String> = Arrays.asList("A", "B")
-        val people: List<Person?> = names.stream().map { name: String -> Person(name) }.collect(Collectors.toList())
+        val names = Arrays.asList("A", "B")
+        val people = names.stream().map { name: String? -> Person(name) }.collect(Collectors.toList())
     }
-}
+}

nj2k/testData/newJ2k/function/varVararg.kt

@@ -1,8 +1,8 @@
 package demo
 
 internal class Test {
-    fun test(vararg args: Any) {
+    fun test(vararg args: Any?) {
         var args = args
-        args = arrayOf(1, 2, 3)
+        args = arrayOf<Int?>(1, 2, 3)
     }
 }

nj2k/testData/newJ2k/inheritance/classOneExtendsBaseWithOneParam.kt

@@ -1,2 +1,2 @@
-internal open class Base(name: String)
-internal class One(name: String, second: String?) : Base(name)
+internal open class Base(name: String?)
+internal class One(name: String?, second: String?) : Base(name) 

nj2k/testData/newJ2k/inheritance/classOneExtendsBaseWithZeroParamsNonEmptyConstructor.kt

@@ -1,2 +1,2 @@
-internal open class Base(name: String)
-internal class One(name: String, private val mySecond: String) : Base(name)
+internal open class Base(name: String?)
+internal class One(name: String?, private val mySecond: String) : Base(name) 

nj2k/testData/newJ2k/issues/kt-19336.kt

@@ -1,6 +1,6 @@
 class TestReturnsArray {
     fun strings(n: Int): Array<String?> {
-        val result = arrayOfNulls<String?>(n)
+        val result = arrayOfNulls<String>(n)
         for (i in 0 until n) {
             result[i] = Integer.toString(i)
         }

nj2k/testData/newJ2k/issues/kt-19348.kt

@@ -2,7 +2,7 @@ class TestMutltipleCtorsWithJavadoc
 /**
  * Javadoc for 1st ctor
  * @param x
- */(private val x: String) {
+ */(private val x: String?) {
     private var y: String? = null
 
     // ---
@@ -14,7 +14,7 @@ class TestMutltipleCtorsWithJavadoc
      * @param x
      * @param y
      */
-    constructor(x: String, y: String?) : this(x) {
+    constructor(x: String?, y: String?) : this(x) {
         this.y = y
     }
 

nj2k/testData/newJ2k/issues/kt-19382.kt

@@ -3,7 +3,7 @@ package test
 import java.util.HashMap
 
 class TestPrimitiveFromMap {
-    fun foo(map: HashMap<String, Int>): Int {
+    fun foo(map: HashMap<String?, Int?>): Int {
         return map["zzz"]!!
     }
 }

nj2k/testData/newJ2k/issues/kt-19383.kt

@@ -1,7 +1,7 @@
 package test
 
 class TestMapGetAsReceiver {
-    fun foo(map: Map<String, String>): Int {
+    fun foo(map: Map<String?, String>): Int {
         return map["zzz"]!!.length
     }
 }

nj2k/testData/newJ2k/issues/kt-19396.kt

@@ -1,9 +1,9 @@
 package test
 
-class TestValReassign(private val s1: String) {
+class TestValReassign(private val s1: String?) {
     private var s2: String? = null
 
-    constructor(s1: String, s2: String?) : this(s1) {
+    constructor(s1: String?, s2: String?) : this(s1) {
         this.s2 = s2
     }
 

nj2k/testData/newJ2k/issues/kt-19550.kt

@@ -3,13 +3,13 @@ class TestToStringReturnsNullable {
         var string: String? = null
     }
 
-    open class Ctor(string: String) : Base() {
+    open class Ctor(string: String?) : Base() {
         init {
             this.string = string
         }
     }
 
-    class Derived(string: String) : Ctor(string) {
+    class Derived(string: String?) : Ctor(string) {
         override fun toString(): String {
             return string!!
         }

nj2k/testData/newJ2k/issues/kt-19639.kt

@@ -6,7 +6,7 @@ class TestJavaExpectedTypeInference {
     fun test(node: DefaultMutableTreeNode) {
         val e: Enumeration<DefaultMutableTreeNode> = node.children()
         while (e.hasMoreElements()) {
-            val child: DefaultMutableTreeNode = e.nextElement()
+            val child = e.nextElement()
             val name = child.userObject as String
             println(name)
         }

nj2k/testData/newJ2k/issues/kt-24677.kt

@@ -1,11 +1,11 @@
 import java.util.ArrayList
 
 internal interface FooInterface {
-    fun foo(): ArrayList<out Foo.SomeClass>?
+    fun foo(): ArrayList<out Foo.SomeClass?>?
 }
 
 class Foo : FooInterface {
-    override fun foo(): ArrayList<SomeClass>? {
+    override fun foo(): ArrayList<SomeClass?>? {
         return null
     }
 

nj2k/testData/newJ2k/issues/kt-32702.kt

@@ -5,6 +5,6 @@ internal class Test {
     fun context() {
         val items: MutableList<Double> = ArrayList()
         items.add(1.0)
-        items.forEach(Consumer { o: Double -> println(o) })
+        items.forEach(Consumer { o: Double? -> println(o) })
     }
 }

nj2k/testData/newJ2k/issues/kt-5294.kt

@@ -1,4 +1,4 @@
-internal class X(private val list: List<Y>) {
+internal class X(private val list: MutableList<Y>) {
 
     internal inner class Y
 }

nj2k/testData/newJ2k/issues/kt-543-boxed.kt

@@ -1,12 +1,10 @@
 package demo
 
 internal class Test {
-    fun putInt(i: Int) {}
-
+    fun putInt(i: Int?) {}
     fun test() {
         val b: Byte = 10
         putInt(b.toInt())
-
         val b2: Byte = 10
         putInt(b2.toInt())
     }

nj2k/testData/newJ2k/issues/kt-543-mixed.kt

@@ -1,8 +1,7 @@
 package demo
 
 internal class Test {
-    fun putInt(i: Int) {}
-
+    fun putInt(i: Int?) {}
     fun test() {
         val i = 10
         putInt(i)

nj2k/testData/newJ2k/issues/kt-792-mixed.kt

@@ -1,6 +1,6 @@
 package demo
 
-internal class Test(i: Int) {
+internal class Test(i: Int?) {
     fun test() {
         val i = 10
         Test(i)

nj2k/testData/newJ2k/issues/kt-807.kt

@@ -13,7 +13,7 @@ internal object FileRead {
             val fstream = FileInputStream(File("file.txt"))
             val `in` = DataInputStream(fstream)
             val br = BufferedReader(InputStreamReader(`in`))
-            var strLine: String
+            var strLine: String?
             while (br.readLine().also { strLine = it } != null) {
                 println(strLine)
             }

nj2k/testData/newJ2k/issues/kt-809-string.kt

@@ -8,9 +8,9 @@ internal object One {
     var myContainer = Container()
 }
 
-internal class StringContainer(s: String)
+internal class StringContainer(s: String?)
 internal class Test {
-    fun putString(s: String) {}
+    fun putString(s: String?) {}
     fun test() {
         putString(One.myContainer.myString)
         StringContainer(One.myContainer.myString)

nj2k/testData/newJ2k/issues/kt-8170.kt

@@ -2,12 +2,12 @@ object ArrayNullable {
     @JvmStatic
     fun main(args: Array<String>) {
         val notNull = 0
-        val a1 = arrayOfNulls<Int?>(2)
+        val a1 = arrayOfNulls<Int>(2)
         a1[0] = null
         a1[1] = notNull
         println(a1[0])
         println(a1[1])
-        val a2 = arrayOfNulls<Int?>(2)
+        val a2 = arrayOfNulls<Int>(2)
         a2[0] = nullable()
         a2[1] = notNull
         println(a2[0])
@@ -21,4 +21,4 @@ object ArrayNullable {
     fun nullable(): Int? {
         return if (System.getProperty("user.home").length > 20) null else 1
     }
-}
+}

nj2k/testData/newJ2k/javaStreamsApi/collectStream.kt

@@ -2,12 +2,12 @@ import java.util.stream.Collectors
 
 internal class Test {
     fun main(lst: List<String>) {
-        val toList: List<String> = lst.stream().collect(Collectors.toList())
-        val toSet: Set<String> = lst.stream().collect(Collectors.toSet())
+        val toList = lst.stream().collect(Collectors.toList())
+        val toSet = lst.stream().collect(Collectors.toSet())
         val count = lst.stream().count()
         val anyMatch = lst.stream().anyMatch { v: String -> v.isEmpty() }
         val allMatch = lst.stream().allMatch { v: String -> v.isEmpty() }
         val noneMatch = lst.stream().noneMatch { v: String -> v.isEmpty() }
-        lst.stream().forEach { v: String -> println(v) }
+        lst.stream().forEach { v: String? -> println(v) }
     }
 }

nj2k/testData/newJ2k/javaStreamsApi/createStream.kt

@@ -4,23 +4,23 @@ import java.util.stream.Stream
 
 internal class Test {
     fun main(lst: List<String>) {
-        val streamOfList: List<String> = lst.stream()
+        val streamOfList = lst.stream()
                 .map { x: String -> x + "e" }
                 .collect(Collectors.toList())
-        val streamOfElements: List<Int> = Stream.of(1, 2, 3)
+        val streamOfElements = Stream.of(1, 2, 3)
                 .map { x: Int -> x + 1 }
                 .collect(Collectors.toList())
         val array = arrayOf(1, 2, 3)
-        val streamOfArray: List<Int> = Arrays.stream(array)
+        val streamOfArray = Arrays.stream(array)
                 .map { x: Int -> x + 1 }
                 .collect(Collectors.toList())
-        val streamOfArray2: List<Int> = Stream.of(*array)
+        val streamOfArray2 = Stream.of(*array)
                 .map { x: Int -> x + 1 }
                 .collect(Collectors.toList())
-        val streamIterate: List<Int> = Stream.iterate(2, { v: Int -> v * 2 })
+        val streamIterate = Stream.iterate(2, { v: Int -> v * 2 })
                 .map { x: Int -> x + 1 }
                 .collect(Collectors.toList())
-        val streamGenerate: List<Int> = Stream.generate { 42 }
+        val streamGenerate = Stream.generate { 42 }
                 .map { x: Int -> x + 1 }
                 .collect(Collectors.toList())
     }

nj2k/testData/newJ2k/javaStreamsApi/dontCollectOnExistingStreams.kt

@@ -3,7 +3,7 @@ import java.util.stream.Stream
 
 internal class Test {
     fun main(lst: List<String?>?) {
-        val stream: Stream<Int> = Stream.of(1)
-        val list: List<Int> = stream.collect(Collectors.toList())
+        val stream = Stream.of(1)
+        val list = stream.collect(Collectors.toList())
     }
 }

nj2k/testData/newJ2k/javaStreamsApi/formatting.kt

@@ -3,11 +3,11 @@ import java.util.stream.Collectors
 
 internal class Test {
     fun main(lst: List<Int>) {
-        val newLst: List<Int> = /*before list*/lst/*after list*/.stream/*before stream*/()/* after stream*/
+        val newLst = /*before list*/lst/*after list*/.stream/*before stream*/()/* after stream*/
                 .filter { x: Int -> x > 10 }
                 .map { x: Int -> x + 2 }/*some comment*/.distinct/*another comment*/()/* one more comment */.sorted()/*another one comment*/
                 .sorted(Comparator.naturalOrder())
-                .peek { x: Int -> println(x) }.limit(1)
+                .peek { x: Int? -> println(x) }.limit(1)
                 .skip(42)/*skipped*/
                 /*collecting one*/.collect/*collecting two */(Collectors.toList())/* cool */
     }

nj2k/testData/newJ2k/javaStreamsApi/kt-21467.kt

@@ -3,14 +3,14 @@ import java.util.stream.Stream
 
 internal class Test {
     fun main() {
-        val activities: List<String> = Stream.of("12")
+        val activities = Stream.of("12")
                 .map { v: String -> v + "nya" }
                 .filter { v: String? -> v != null }
                 .flatMap { v: String ->
                     Stream.of(v)
                             .flatMap { s: String -> Stream.of(s) }
                 }.filter { v: String ->
-                    val name: String = v.javaClass.name
+                    val name = v.javaClass.name
                     if (name == "name") {
                         return@filter false
                     }

nj2k/testData/newJ2k/javaStreamsApi/streamOperations.kt

@@ -3,13 +3,13 @@ import java.util.stream.Collectors
 
 internal class Test {
     fun main(lst: List<Int>) {
-        val newLst: List<Int> = lst.stream()
+        val newLst = lst.stream()
                 .filter { x: Int -> x > 10 }
                 .map { x: Int -> x + 2 }
                 .distinct()
                 .sorted()
                 .sorted(Comparator.naturalOrder())
-                .peek { x: Int -> println(x) }
+                .peek { x: Int? -> println(x) }
                 .limit(1)
                 .skip(42)
                 .collect(Collectors.toList())

nj2k/testData/newJ2k/list/ForEach.kt

@@ -4,7 +4,7 @@ import java.util.ArrayList
 class ForEach {
     fun test() {
         val xs = ArrayList<Any>()
-        val ys: MutableList<Any> = LinkedList<Any?>()
+        val ys: MutableList<Any> = LinkedList<Any>()
         for (x in xs) {
             ys.add(x)
         }

nj2k/testData/newJ2k/list/Lists.kt

@@ -4,7 +4,7 @@ import java.util.ArrayList
 class Lists {
     fun test() {
         val xs: MutableList<Any?> = ArrayList()
-        val ys: MutableList<Any?> = LinkedList<Any?>()
+        val ys: MutableList<Any?> = LinkedList<Any>()
         val zs = ArrayList<Any?>()
         xs.add(null)
         ys.add(null)

nj2k/testData/newJ2k/literalExpression/double.kt

@@ -9,10 +9,8 @@ internal class A {
     private val d8 = 1.0
     private val d9 = 1.0
     private val x = 1 / (1.0 + 0)
-
     fun foo1(d: Double) {}
-    fun foo2(d: Double) {}
-
+    fun foo2(d: Double?) {}
     fun bar() {
         foo1(1.0)
         foo1(1.0)

nj2k/testData/newJ2k/literalExpression/float.kt

@@ -9,10 +9,8 @@ internal class A {
     private val f8 = +1f
     private val f9 = 1f
     private val f10 = 1f
-
     fun foo1(f: Float) {}
-    fun foo2(f: Float) {}
-
+    fun foo2(f: Float?) {}
     fun bar() {
         foo1(1f)
         foo2(1f)

nj2k/testData/newJ2k/literalExpression/long.kt

@@ -7,10 +7,8 @@ internal class A {
     private val l6 = -123456789101112
     private val l7: Long = +1
     private val l8 = +1L
-
     fun foo1(l: Long) {}
-    fun foo2(l: Long) {}
-
+    fun foo2(l: Long?) {}
     fun bar() {
         foo1(1)
         foo1(1L)