New J2K: separate nullability inference from common one & nullability bug fixes

It will be needed for structure mutability inference

#KT-21467 fixed
#KT-32609 fixed
#KT-32572 fixed
#KT-24677 fixed

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * 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.generators.tests
@@ -154,8 +143,9 @@ import org.jetbrains.kotlin.kapt3.test.AbstractClassFileToSourceStubConverterTes
 import org.jetbrains.kotlin.kapt3.test.AbstractKotlinKaptContextTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinConverterSingleFileTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinCopyPasteConversionTest
-import org.jetbrains.kotlin.nj2k.AbstractNullabilityAnalysisTest
 import org.jetbrains.kotlin.nj2k.AbstractTextNewJavaToKotlinCopyPasteConversionTest
+import org.jetbrains.kotlin.nj2k.inference.common.AbstractCommonConstraintCollectorTest
+import org.jetbrains.kotlin.nj2k.inference.nullability.AbstractNullabilityInferenceTest
 import org.jetbrains.kotlin.noarg.AbstractBlackBoxCodegenTestForNoArg
 import org.jetbrains.kotlin.noarg.AbstractBytecodeListingTestForNoArg
 import org.jetbrains.kotlin.psi.patternMatching.AbstractPsiUnifierTest
@@ -987,15 +977,18 @@ fun main(args: Array<String>) {
         testClass<AbstractNewJavaToKotlinConverterSingleFileTest> {
             model("newJ2k", pattern = """^([^\.]+)\.java$""")
         }
+        testClass<AbstractCommonConstraintCollectorTest> {
+            model("inference/common")
+        }
+        testClass<AbstractNullabilityInferenceTest> {
+            model("inference/nullability")
+        }
         testClass<AbstractNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPaste", pattern = """^([^\.]+)\.java$""")
         }
         testClass<AbstractTextNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPastePlainText", pattern = """^([^\.]+)\.txt$""")
         }
-        testClass<AbstractNullabilityAnalysisTest> {
-            model("nullabilityAnalysis")
-        }
     }
 
     testGroup("jps-plugin/jps-tests/test", "jps-plugin/testData") {

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.183

@@ -159,8 +159,9 @@ import org.jetbrains.kotlin.kapt3.test.AbstractClassFileToSourceStubConverterTes
 import org.jetbrains.kotlin.kapt3.test.AbstractKotlinKaptContextTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinConverterSingleFileTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinCopyPasteConversionTest
-import org.jetbrains.kotlin.nj2k.AbstractNullabilityAnalysisTest
 import org.jetbrains.kotlin.nj2k.AbstractTextNewJavaToKotlinCopyPasteConversionTest
+import org.jetbrains.kotlin.nj2k.inference.common.AbstractCommonConstraintCollectorTest
+import org.jetbrains.kotlin.nj2k.inference.nullability.AbstractNullabilityInferenceTest
 import org.jetbrains.kotlin.noarg.AbstractBlackBoxCodegenTestForNoArg
 import org.jetbrains.kotlin.noarg.AbstractBytecodeListingTestForNoArg
 import org.jetbrains.kotlin.psi.patternMatching.AbstractPsiUnifierTest
@@ -992,15 +993,18 @@ fun main(args: Array<String>) {
         testClass<AbstractNewJavaToKotlinConverterSingleFileTest> {
             model("newJ2k", pattern = """^([^\.]+)\.java$""")
         }
+        testClass<AbstractCommonConstraintCollectorTest> {
+            model("inference/common")
+        }
+        testClass<AbstractNullabilityInferenceTest> {
+            model("inference/nullability")
+        }
         testClass<AbstractNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPaste", pattern = """^([^\.]+)\.java$""")
         }
         testClass<AbstractTextNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPastePlainText", pattern = """^([^\.]+)\.txt$""")
         }
-        testClass<AbstractNullabilityAnalysisTest> {
-            model("nullabilityAnalysis")
-        }
     }
 
     testGroup("jps-plugin/jps-tests/test", "jps-plugin/testData") {

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.as33

@@ -143,8 +143,9 @@ import org.jetbrains.kotlin.kapt3.test.AbstractClassFileToSourceStubConverterTes
 import org.jetbrains.kotlin.kapt3.test.AbstractKotlinKaptContextTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinConverterSingleFileTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinCopyPasteConversionTest
-import org.jetbrains.kotlin.nj2k.AbstractNullabilityAnalysisTest
 import org.jetbrains.kotlin.nj2k.AbstractTextNewJavaToKotlinCopyPasteConversionTest
+import org.jetbrains.kotlin.nj2k.inference.common.AbstractCommonConstraintCollectorTest
+import org.jetbrains.kotlin.nj2k.inference.nullability.AbstractNullabilityInferenceTest
 import org.jetbrains.kotlin.noarg.AbstractBlackBoxCodegenTestForNoArg
 import org.jetbrains.kotlin.noarg.AbstractBytecodeListingTestForNoArg
 import org.jetbrains.kotlin.psi.patternMatching.AbstractPsiUnifierTest
@@ -952,15 +953,18 @@ fun main(args: Array<String>) {
         testClass<AbstractNewJavaToKotlinConverterSingleFileTest> {
             model("newJ2k", pattern = """^([^\.]+)\.java$""")
         }
+        testClass<AbstractCommonConstraintCollectorTest> {
+            model("inference/common")
+        }
+        testClass<AbstractNullabilityInferenceTest> {
+            model("inference/nullability")
+        }
         testClass<AbstractNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPaste", pattern = """^([^\.]+)\.java$""")
         }
         testClass<AbstractTextNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPastePlainText", pattern = """^([^\.]+)\.txt$""")
         }
-        testClass<AbstractNullabilityAnalysisTest> {
-            model("nullabilityAnalysis")
-        }
     }
 
 /*  There is no jps in AS

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.as34

@@ -143,8 +143,9 @@ import org.jetbrains.kotlin.kapt3.test.AbstractClassFileToSourceStubConverterTes
 import org.jetbrains.kotlin.kapt3.test.AbstractKotlinKaptContextTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinConverterSingleFileTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinCopyPasteConversionTest
-import org.jetbrains.kotlin.nj2k.AbstractNullabilityAnalysisTest
 import org.jetbrains.kotlin.nj2k.AbstractTextNewJavaToKotlinCopyPasteConversionTest
+import org.jetbrains.kotlin.nj2k.inference.common.AbstractCommonConstraintCollectorTest
+import org.jetbrains.kotlin.nj2k.inference.nullability.AbstractNullabilityInferenceTest
 import org.jetbrains.kotlin.noarg.AbstractBlackBoxCodegenTestForNoArg
 import org.jetbrains.kotlin.noarg.AbstractBytecodeListingTestForNoArg
 import org.jetbrains.kotlin.psi.patternMatching.AbstractPsiUnifierTest
@@ -956,15 +957,18 @@ fun main(args: Array<String>) {
         testClass<AbstractNewJavaToKotlinConverterSingleFileTest> {
             model("newJ2k", pattern = """^([^\.]+)\.java$""")
         }
+        testClass<AbstractCommonConstraintCollectorTest> {
+            model("inference/common")
+        }
+        testClass<AbstractNullabilityInferenceTest> {
+            model("inference/nullability")
+        }
         testClass<AbstractNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPaste", pattern = """^([^\.]+)\.java$""")
         }
         testClass<AbstractTextNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPastePlainText", pattern = """^([^\.]+)\.txt$""")
         }
-        testClass<AbstractNullabilityAnalysisTest> {
-            model("nullabilityAnalysis")
-        }
     }
 
 /*  There is no jps in AS

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.as35

@@ -143,8 +143,9 @@ import org.jetbrains.kotlin.kapt3.test.AbstractClassFileToSourceStubConverterTes
 import org.jetbrains.kotlin.kapt3.test.AbstractKotlinKaptContextTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinConverterSingleFileTest
 import org.jetbrains.kotlin.nj2k.AbstractNewJavaToKotlinCopyPasteConversionTest
-import org.jetbrains.kotlin.nj2k.AbstractNullabilityAnalysisTest
 import org.jetbrains.kotlin.nj2k.AbstractTextNewJavaToKotlinCopyPasteConversionTest
+import org.jetbrains.kotlin.nj2k.inference.common.AbstractCommonConstraintCollectorTest
+import org.jetbrains.kotlin.nj2k.inference.nullability.AbstractNullabilityInferenceTest
 import org.jetbrains.kotlin.noarg.AbstractBlackBoxCodegenTestForNoArg
 import org.jetbrains.kotlin.noarg.AbstractBytecodeListingTestForNoArg
 import org.jetbrains.kotlin.psi.patternMatching.AbstractPsiUnifierTest
@@ -952,15 +953,18 @@ fun main(args: Array<String>) {
         testClass<AbstractNewJavaToKotlinConverterSingleFileTest> {
             model("newJ2k", pattern = """^([^\.]+)\.java$""")
         }
+        testClass<AbstractCommonConstraintCollectorTest> {
+            model("inference/common")
+        }
+        testClass<AbstractNullabilityInferenceTest> {
+            model("inference/nullability")
+        }
         testClass<AbstractNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPaste", pattern = """^([^\.]+)\.java$""")
         }
         testClass<AbstractTextNewJavaToKotlinCopyPasteConversionTest> {
             model("copyPastePlainText", pattern = """^([^\.]+)\.txt$""")
         }
-        testClass<AbstractNullabilityAnalysisTest> {
-            model("nullabilityAnalysis")
-        }
     }
 
 /*  There is no jps in AS

idea/idea-test-framework/test/org/jetbrains/kotlin/idea/test/testUtils.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * 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.idea.test
@@ -20,6 +9,7 @@ import com.intellij.openapi.editor.Document
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.testFramework.LightPlatformTestCase
+import org.jetbrains.kotlin.diagnostics.DiagnosticFactory
 import org.jetbrains.kotlin.diagnostics.Severity
 import org.jetbrains.kotlin.diagnostics.rendering.DefaultErrorMessages
 import org.jetbrains.kotlin.idea.caches.project.LibraryModificationTracker
@@ -29,11 +19,13 @@ import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
 import java.util.*
 
-fun KtFile.dumpTextWithErrors(): String {
+fun KtFile.dumpTextWithErrors(ignoreErrors: Set<DiagnosticFactory<*>> = emptySet()): String {
     val text = text
     if (InTextDirectivesUtils.isDirectiveDefined(text, "// DISABLE-ERRORS")) return text
     val diagnostics = analyzeWithContent().diagnostics
-    val errors = diagnostics.filter { it.severity == Severity.ERROR }
+    val errors = diagnostics.filter { diagnostic ->
+        diagnostic.severity == Severity.ERROR && diagnostic.factory !in ignoreErrors
+    }
     if (errors.isEmpty()) return text
     val header = errors.joinToString("\n", postfix = "\n") { "// ERROR: " + DefaultErrorMessages.render(it).replace('\n', ' ') }
     return header + text

j2k/tests/org/jetbrains/kotlin/j2k/AbstractJavaToKotlinConverterSingleFileTest.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * 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.j2k
@@ -27,6 +16,7 @@ import org.jetbrains.kotlin.idea.j2k.J2kPostProcessor
 import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
 import org.jetbrains.kotlin.idea.test.dumpTextWithErrors
 import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
 import org.jetbrains.kotlin.test.KotlinTestUtils
 import java.io.File
 import java.util.regex.Pattern
@@ -73,7 +63,8 @@ abstract class AbstractJavaToKotlinConverterSingleFileTest : AbstractJavaToKotli
         var actual = reformat(rawConverted, project, reformatInFun)
 
         if (prefix == "file") {
-            actual = createKotlinFile(actual).dumpTextWithErrors()
+            actual = createKotlinFile(actual)
+                .dumpTextWithErrors(setOf(element = ErrorsJvm.INTERFACE_STATIC_METHOD_CALL_FROM_JAVA6_TARGET_ERROR))
         }
 
 

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

@@ -0,0 +1,259 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.KtNodeTypes
+import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
+import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isNullExpression
+import org.jetbrains.kotlin.idea.references.mainReference
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.Variance
+import org.jetbrains.kotlin.types.typeUtil.builtIns
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+interface BoundTypeCalculator {
+    fun expressionsWithBoundType(): List<Pair<KtExpression, BoundType>>
+
+    fun KtExpression.boundType(inferenceContext: InferenceContext): BoundType
+
+    fun KotlinType.boundType(
+        typeVariable: TypeVariable? = null,
+        contextBoundType: BoundType? = null,
+        call: ResolvedCall<*>? = null,
+        isImplicitReceiver: Boolean = false,
+        forceEnhance: Boolean = false,
+        inferenceContext: InferenceContext
+    ): BoundType
+}
+
+class BoundTypeCalculatorImpl(
+    private val resolutionFacade: ResolutionFacade,
+    private val enhancer: BoundTypeEnhancer
+) : BoundTypeCalculator {
+    private val cache = mutableMapOf<KtExpression, BoundType>()
+
+    override fun expressionsWithBoundType() = cache.toList()
+
+    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
+
+    private fun KtIfExpression.toBoundTypeAsIfExpression(inferenceContext: InferenceContext): BoundType? {
+        val isNullLiteralPossible = then?.isNullExpression() == true || `else`?.isNullExpression() == true
+        if (isNullLiteralPossible) {
+            return BoundType.NULL
+        }
+        return (then ?: `else`)?.boundType(inferenceContext) //TODO handle both cases separatelly
+    }
+
+    private fun KtLambdaExpression.toBoundTypeAsLambdaExpression(inferenceContext: InferenceContext): BoundType? {
+        val descriptor = functionLiteral.resolveToDescriptorIfAny(resolutionFacade).safeAs<FunctionDescriptor>() ?: return null
+        val builtIns = getType(analyze())?.builtIns ?: return null
+        val prototypeDescriptor = builtIns.getFunction(valueParameters.size)
+        val parameterBoundTypes = if (descriptor.valueParameters.size == valueParameters.size) {
+            valueParameters.map { parameter ->
+                parameter.typeReference?.typeElement?.let { typeElement ->
+                    inferenceContext.typeElementToTypeVariable[typeElement]
+                }?.let { typeVariable ->
+                    typeVariable.asBoundType()
+                } ?: return null
+            }
+        } else {
+            descriptor.valueParameters.map { parameter ->
+                parameter.type.boundType(inferenceContext = inferenceContext)
+            }
+        }
+        val returnTypeTypeVariable = inferenceContext.declarationToTypeVariable[functionLiteral] ?: return null
+        val returnTypeParameter =
+            TypeParameter(
+                BoundTypeImpl(
+                    TypeVariableLabel(returnTypeTypeVariable),
+                    returnTypeTypeVariable.typeParameters
+                ),
+                Variance.OUT_VARIANCE
+            )
+        return BoundTypeImpl(
+            GenericLabel(prototypeDescriptor.classReference),
+            parameterBoundTypes.map { TypeParameter(it, Variance.IN_VARIANCE) } + returnTypeParameter
+        )
+    }
+
+    private fun KtNameReferenceExpression.toBoundTypeAsReferenceExpression(inferenceContext: InferenceContext): BoundType? =
+        mainReference
+            .resolve()
+            ?.safeAs<KtDeclaration>()
+            ?.let { declaration ->
+                val boundType = inferenceContext.declarationToTypeVariable[declaration]?.asBoundType()
+                    ?: return@let null
+                if (declaration.safeAs<KtParameter>()?.isVarArg == true) {
+                    val arrayClassReference =
+                        declaration.resolveToDescriptorIfAny(resolutionFacade)
+                            ?.safeAs<ValueParameterDescriptor>()
+                            ?.returnType
+                            ?.constructor
+                            ?.declarationDescriptor
+                            ?.safeAs<ClassDescriptor>()
+                            ?.classReference ?: NoClassReference
+                    BoundTypeImpl(
+                        GenericLabel(arrayClassReference),
+                        listOf(TypeParameter(boundType, Variance.INVARIANT))
+                    )
+                } else boundType
+            }
+
+
+    private fun KtBinaryExpressionWithTypeRHS.toBoundTypeAsCastExpression(inferenceContext: InferenceContext): BoundType? =
+        right?.typeElement
+            ?.let { inferenceContext.typeElementToTypeVariable[it]?.asBoundType() }
+
+
+    private fun KtExpression.toBoundTypeAsCallableExpression(
+        contextBoundType: BoundType?,
+        inferenceContext: InferenceContext
+    ): BoundType? {
+        val call = getResolvedCall(analyze(resolutionFacade)) ?: return null
+        val returnType = call.candidateDescriptor.original.returnType ?: return null
+        val callDescriptor = call.candidateDescriptor.original
+        val returnTypeVariable = inferenceContext.declarationDescriptorToTypeVariable[callDescriptor]
+        val withImplicitContextBoundType = contextBoundType
+            ?: call.dispatchReceiver
+                ?.type
+                ?.boundType(inferenceContext = inferenceContext)
+
+        return returnType.boundType(
+            returnTypeVariable,
+            withImplicitContextBoundType,
+            call,
+            withImplicitContextBoundType != contextBoundType,
+            false,
+            inferenceContext
+        )
+    }
+
+    private fun KtQualifiedExpression.toBoundTypeAsQualifiedExpression(inferenceContext: InferenceContext): BoundType? {
+        val receiverBoundType = receiverExpression.boundType(inferenceContext)
+        val selectorExpression = selectorExpression ?: return null
+        return selectorExpression.toBoundTypeAsCallableExpression(receiverBoundType, inferenceContext)
+    }
+
+    override fun KotlinType.boundType(
+        typeVariable: TypeVariable?,
+        contextBoundType: BoundType?,
+        call: ResolvedCall<*>?,
+        isImplicitReceiver: Boolean,
+        forceEnhance: Boolean,
+        inferenceContext: InferenceContext
+    ) = boundTypeUnenhanced(
+        typeVariable,
+        contextBoundType,
+        call,
+        isImplicitReceiver,
+        inferenceContext
+    )?.let { boundType ->
+        val needEnhance = run {
+            if (forceEnhance) return@run true
+            !inferenceContext.isInConversionScope(
+                call?.call?.calleeExpression?.mainReference?.resolve() ?: return@run false
+            )
+        }
+        if (needEnhance) enhancer.enhanceKotlinType(this, boundType, forceEnhance, inferenceContext)
+        else boundType
+    } ?: BoundType.LITERAL
+
+    private fun KotlinType.boundTypeUnenhanced(
+        typeVariable: TypeVariable?,
+        contextBoundType: BoundType?,
+        call: ResolvedCall<*>?,
+        isImplicitReceiver: Boolean,
+        inferenceContext: InferenceContext
+    ): BoundType? {
+        return when (val target = constructor.declarationDescriptor) {
+            is ClassDescriptor ->
+                BoundTypeImpl(
+                    typeVariable?.let { TypeVariableLabel(it) } ?: GenericLabel(target.classReference),
+                    arguments.mapIndexed { i, argument ->
+                        TypeParameter(
+                            argument.type.boundTypeUnenhanced(
+                                typeVariable?.typeParameters?.get(i)?.boundType?.label?.safeAs<TypeVariableLabel>()?.typeVariable,
+                                contextBoundType,
+                                call,
+                                isImplicitReceiver,
+                                inferenceContext
+                            ) ?: return null,
+                            constructor.parameters[i].variance
+                        )
+                    }
+                )
+
+            is TypeParameterDescriptor -> {
+                val containingDeclaration = target.containingDeclaration
+                when {
+                    containingDeclaration == call?.candidateDescriptor?.original -> {
+                        val returnTypeVariable = inferenceContext.typeElementToTypeVariable[
+                                call.call.typeArguments.getOrNull(target.index)?.typeReference?.typeElement ?: return null
+                        ] ?: return null
+                        BoundTypeImpl(
+                            TypeVariableLabel(returnTypeVariable),
+                            returnTypeVariable.typeParameters
+                        )
+                    }
+                    typeVariable != null && isImplicitReceiver ->
+                        BoundTypeImpl(
+                            TypeVariableLabel(typeVariable),
+                            emptyList()
+                        )
+                    contextBoundType?.isReferenceToClass == true ->
+                        contextBoundType.typeParameters.getOrNull(target.index)?.boundType
+
+                    // `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
+                        BoundTypeImpl(
+                            TypeVariableLabel(returnTypeVariable),
+                            returnTypeVariable.typeParameters
+                        )
+                    }
+                    else -> BoundTypeImpl(
+                        TypeParameterLabel(target),
+                        emptyList()
+                    )
+                }
+            }
+            else -> null
+        }
+    }
+}
+
+

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

@@ -0,0 +1,39 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.types.KotlinType
+
+abstract class BoundTypeEnhancer {
+    abstract fun enhance(
+        expression: KtExpression,
+        boundType: BoundType,
+        inferenceContext: InferenceContext
+    ): BoundType
+
+    abstract fun enhanceKotlinType(
+        type: KotlinType,
+        boundType: BoundType,
+        allowLowerEnhancement: Boolean,
+        inferenceContext: InferenceContext
+    ): BoundType
+
+    object ID : BoundTypeEnhancer() {
+        override fun enhance(
+            expression: KtExpression,
+            boundType: BoundType,
+            inferenceContext: InferenceContext
+        ): BoundType = boundType
+
+        override fun enhanceKotlinType(
+            type: KotlinType,
+            boundType: BoundType,
+            allowLowerEnhancement: Boolean,
+            inferenceContext: InferenceContext
+        ): BoundType = boundType
+    }
+}

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

@@ -0,0 +1,38 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.ClassifierDescriptor
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.resolve.BindingContext
+
+class ClassSubstitutor(private val superTypes: Map<ClassifierDescriptor, Map<TypeParameterDescriptor, KtTypeElement>>) {
+    operator fun get(klass: ClassDescriptor, typeParameter: TypeParameterDescriptor): KtTypeElement? =
+        superTypes[klass]?.get(typeParameter)
+
+    companion object {
+        fun createFromKtClass(klass: KtClassOrObject, resolutionFacade: ResolutionFacade): ClassSubstitutor? {
+            val superTypes =
+                klass.superTypeListEntries.map { superType ->
+                    val typeReference = superType.typeReference ?: return null
+                    val type = typeReference.analyze(resolutionFacade)[BindingContext.TYPE, typeReference] ?: return null
+                    val declarationDescriptor = type.constructor.declarationDescriptor ?: return null
+                    declarationDescriptor to type.constructor.parameters.zip(
+                        typeReference.typeElement?.typeArgumentsAsTypes ?: return null
+                    ) { parameter, argument ->
+                        parameter to (argument.typeElement ?: return null)
+                    }.toMap()
+                }.toMap()
+            return ClassSubstitutor(superTypes)
+        }
+    }
+}
+

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

@@ -0,0 +1,81 @@
+/*
+ * 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
+
+enum class ConstraintPriority {
+    /* order of entries here used when solving system of constraints */
+    SUPER_DECLARATION,
+    INITIALIZER,
+    RETURN,
+    ASSIGNMENT,
+    PARAMETER,
+    RECEIVER_PARAMETER,
+    COMPARE_WITH_NULL,
+    USE_AS_RECEIVER,
+}
+
+sealed class Constraint {
+    abstract val priority: ConstraintPriority
+}
+
+class SubtypeConstraint(
+    var subtype: ConstraintBound,
+    var supertype: ConstraintBound,
+    override val priority: ConstraintPriority
+) : Constraint() {
+    operator fun component1() = subtype
+    operator fun component2() = supertype
+}
+
+class EqualsConstraint(
+    var left: ConstraintBound,
+    var right: ConstraintBound,
+    override val priority: ConstraintPriority
+) : Constraint() {
+    operator fun component1() = left
+    operator fun component2() = right
+}
+
+fun Constraint.copy() = when (this) {
+    is SubtypeConstraint -> SubtypeConstraint(subtype, supertype, priority)
+    is EqualsConstraint -> EqualsConstraint(left, right, priority)
+}
+
+sealed class ConstraintBound
+class TypeVariableBound(val typeVariable: TypeVariable) : ConstraintBound()
+class LiteralBound private constructor(val state: State) : ConstraintBound() {
+    companion object {
+        val UPPER = LiteralBound(State.UPPER)
+        val LOWER = LiteralBound(State.LOWER)
+        val UNKNOWN = LiteralBound(State.UNKNOWN)
+    }
+}
+
+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
+    }

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

@@ -0,0 +1,136 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.types.Variance
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+@Suppress("unused")
+class ConstraintBuilder(
+    private val inferenceContext: InferenceContext,
+    private val boundTypeCalculator: BoundTypeCalculator
+) : BoundTypeCalculator by boundTypeCalculator {
+    private val constraints = mutableListOf<Constraint>()
+
+    fun TypeVariable.isSubtypeOf(supertype: BoundType, priority: ConstraintPriority) {
+        asBoundType().isSubtypeOf(supertype, priority)
+    }
+
+    fun TypeVariable.isSubtypeOf(supertype: TypeVariable, priority: ConstraintPriority) {
+        asBoundType().isSubtypeOf(supertype.asBoundType(), priority)
+    }
+
+    fun KtExpression.isSubtypeOf(supertype: KtExpression, priority: ConstraintPriority) {
+        boundType().isSubtypeOf(supertype.boundType(), priority)
+    }
+
+    fun KtExpression.isSubtypeOf(supertype: TypeVariable, priority: ConstraintPriority) {
+        boundType().isSubtypeOf(supertype.asBoundType(), priority)
+    }
+
+    fun KtExpression.isSubtypeOf(supertype: BoundType, priority: ConstraintPriority) {
+        boundType().isSubtypeOf(supertype, priority)
+    }
+
+    fun KtExpression.isTheSameTypeAs(other: State, priority: ConstraintPriority) {
+        boundType().label.safeAs<TypeVariableLabel>()?.typeVariable?.let { typeVariable ->
+            constraints += EqualsConstraint(typeVariable.constraintBound, other.constraintBound, priority)
+        }
+    }
+
+    fun TypeVariable.isTheSameTypeAs(other: BoundType, priority: ConstraintPriority) {
+        asBoundType().isTheSameTypeAs(other, priority)
+    }
+
+    fun TypeVariable.isTheSameTypeAs(
+        other: TypeVariable,
+        priority: ConstraintPriority,
+        ignoreTypeVariables: Set<TypeVariable> = emptySet()
+    ) {
+        asBoundType().isTheSameTypeAs(other.asBoundType(), priority, ignoreTypeVariables)
+    }
+
+    fun KtTypeElement.isTheSameTypeAs(
+        other: KtTypeElement,
+        priority: ConstraintPriority,
+        ignoreTypeVariables: Set<TypeVariable> = emptySet()
+    ) {
+        inferenceContext.typeElementToTypeVariable[this]
+            ?.asBoundType()
+            ?.isTheSameTypeAs(
+                inferenceContext.typeElementToTypeVariable[other]?.asBoundType() ?: return,
+                priority,
+                ignoreTypeVariables
+            )
+    }
+
+    fun TypeVariable.isTheSameTypeAs(
+        other: KtTypeElement,
+        priority: ConstraintPriority,
+        ignoreTypeVariables: Set<TypeVariable> = emptySet()
+    ) {
+        asBoundType().isTheSameTypeAs(
+            inferenceContext.typeElementToTypeVariable[other]?.asBoundType() ?: return,
+            priority,
+            ignoreTypeVariables
+        )
+    }
+
+    fun BoundType.isTheSameTypeAs(
+        other: KtTypeElement,
+        priority: ConstraintPriority,
+        ignoreTypeVariables: Set<TypeVariable> = emptySet()
+    ) {
+        isTheSameTypeAs(
+            inferenceContext.typeElementToTypeVariable[other]?.asBoundType() ?: return,
+            priority,
+            ignoreTypeVariables
+        )
+    }
+
+    fun BoundType.isTheSameTypeAs(
+        other: BoundType,
+        priority: ConstraintPriority,
+        ignoreTypeVariables: Set<TypeVariable> = emptySet()
+    ) {
+        (typeParameters zip other.typeParameters).forEach { (left, right) ->
+            left.boundType.isTheSameTypeAs(right.boundType, priority, ignoreTypeVariables)
+        }
+
+        if (typeVariable !in ignoreTypeVariables && other.typeVariable !in ignoreTypeVariables) {
+            constraints += EqualsConstraint(
+                constraintBound ?: return,
+                other.constraintBound ?: return,
+                priority
+            )
+        }
+    }
+
+    fun BoundType.isSubtypeOf(supertype: BoundType, priority: ConstraintPriority) {
+        (typeParameters zip supertype.typeParameters).forEach { (left, right) ->
+            when (left.variance) {
+                Variance.OUT_VARIANCE -> left.boundType.isSubtypeOf(right.boundType, priority)
+                Variance.IN_VARIANCE -> right.boundType.isSubtypeOf(left.boundType, priority)
+                Variance.INVARIANT -> right.boundType.isTheSameTypeAs(left.boundType, priority)
+            }
+        }
+
+        constraints += SubtypeConstraint(
+            constraintBound ?: return,
+            supertype.constraintBound ?: return,
+            priority
+        )
+    }
+
+    fun KtExpression.boundType() = with(boundTypeCalculator) {
+        this@boundType.boundType(inferenceContext)
+    }
+
+    val collectedConstraints: List<Constraint>
+        get() = constraints
+}

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

@@ -0,0 +1,42 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.inference.common.collectors.ConstraintsCollector
+import org.jetbrains.kotlin.nj2k.parentOfType
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.psiUtil.forEachDescendantOfType
+
+class ConstraintsCollectorAggregator(
+    private val resolutionFacade: ResolutionFacade,
+    private val collectors: List<ConstraintsCollector>
+) {
+    fun collectConstraints(
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        elements: List<KtElement>
+    ): List<Constraint> {
+        val constraintsBuilder = ConstraintBuilder(inferenceContext, boundTypeCalculator)
+        for (element in elements) {
+            element.forEachDescendantOfType<KtElement> { innerElement ->
+                if (innerElement.parentOfType<KtImportDirective>() != null) return@forEachDescendantOfType
+                for (collector in collectors) {
+                    with(collector) {
+                        constraintsBuilder.collectConstraints(
+                            innerElement,
+                            boundTypeCalculator,
+                            inferenceContext,
+                            resolutionFacade
+                        )
+                    }
+                }
+            }
+        }
+        return constraintsBuilder.collectedConstraints
+    }
+}

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

@@ -0,0 +1,196 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+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.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.typeUtil.isUnit
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+abstract class ContextCollector(private val resolutionFacade: ResolutionFacade) {
+    private fun KotlinType.classReference(): ClassReference? =
+        when (val descriptor = constructor.declarationDescriptor) {
+            is ClassDescriptor -> descriptor.classReference
+            is TypeParameterDescriptor -> TypeParameterReference(descriptor)
+            else -> null
+        }
+
+    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)
+    }
+
+    fun collectTypeVariables(elements: List<KtElement>): InferenceContext {
+        val declarationToTypeVariable = mutableMapOf<KtNamedDeclaration, TypeVariable>()
+        val typeElementToTypeVariable = mutableMapOf<KtTypeElement, TypeVariable>()
+        val typeBasedTypeVariables = mutableListOf<TypeBasedTypeVariable>()
+
+        fun KtTypeReference.toBoundType(defaultState: State? = null): BoundType? {
+            val typeElement = typeElement ?: return null
+            val classReference = classReference() ?: NoClassReference
+
+            val state = when {
+                classReference.descriptor?.defaultType?.isUnit() == true -> State.LOWER
+                defaultState != null -> defaultState
+                else -> classReference.getState(typeElement)
+            }
+            val typeArguments =
+                if (classReference is DescriptorClassReference) {
+                    typeElement.typeArgumentsAsTypes.zip(
+                        classReference.descriptor.declaredTypeParameters
+                    ) { typeArgument, typeParameter ->
+                        TypeParameter(
+                            if (typeArgument == null) {
+                                BoundTypeImpl(StarProjectionLabel, emptyList())
+                            } else typeArgument.toBoundType() ?: BoundType.STAR_PROJECTION,
+                            typeParameter.variance
+                        )
+                    }
+                } else emptyList()
+
+            return if (state == null) {
+                BoundTypeImpl(
+                    GenericLabel(classReference),
+                    typeArguments
+                )
+            } else {
+                val typeVariable = TypeElementBasedTypeVariable(
+                    classReference,
+                    typeArguments,
+                    typeElement.toData(),
+                    state
+                )
+                typeElementToTypeVariable[typeElement] = typeVariable
+                typeVariable.asBoundType()
+            }
+        }
+
+        fun KotlinType.toBoundType(): BoundType? {
+            val classReference = classReference() ?: NoClassReference
+            val state = classReference.getState(typeElement = null)
+
+            val typeArguments =
+                if (classReference is DescriptorClassReference) {
+                    arguments.zip(classReference.descriptor.declaredTypeParameters) { typeArgument, typeParameter ->
+                        TypeParameter(
+                            typeArgument.type.toBoundType() ?: BoundType.STAR_PROJECTION,
+                            typeParameter.variance
+                        )
+                    }
+                } else emptyList()
+
+            return if (state == null) {
+                BoundTypeImpl(
+                    GenericLabel(classReference),
+                    typeArguments
+                )
+            } else {
+                val typeVariable = TypeBasedTypeVariable(
+                    classReference,
+                    typeArguments,
+                    this,
+                    state
+                )
+                typeBasedTypeVariables += typeVariable
+                typeVariable.asBoundType()
+            }
+        }
+
+        val substitutors = mutableMapOf<ClassDescriptor, ClassSubstitutor>()
+
+        for (element in elements) {
+            element.forEachDescendantOfType<KtExpression> { expression ->
+                if (expression is KtCallableDeclaration
+                    && (expression is KtParameter
+                            || expression is KtProperty
+                            || expression is KtNamedFunction)
+                ) run {
+                    val typeReference = expression.typeReference ?: return@run
+                    val typeVariable = typeReference.toBoundType()?.typeVariable ?: return@run
+                    declarationToTypeVariable[expression] = typeVariable
+                }
+
+                if (expression is KtTypeParameterListOwner) {
+                    for (typeParameter in expression.typeParameters) {
+                        typeParameter.extendsBound?.toBoundType(defaultState = State.UPPER)
+                    }
+                    for (constraint in expression.typeConstraints) {
+                        constraint.boundTypeReference?.toBoundType(defaultState = State.UPPER)
+                    }
+                }
+
+                when (expression) {
+                    is KtClass -> {
+                        for (entry in expression.superTypeListEntries) {
+                            for (argument in entry.typeReference?.typeElement?.typeArgumentsAsTypes ?: continue) {
+                                argument.toBoundType()
+                            }
+                        }
+                        val descriptor =
+                            expression.resolveToDescriptorIfAny(resolutionFacade) ?: return@forEachDescendantOfType
+                        substitutors[descriptor] =
+                            ClassSubstitutor.createFromKtClass(expression, resolutionFacade) ?: return@forEachDescendantOfType
+                        for (typeParameter in expression.typeParameters) {
+                            val typeVariable = typeParameter.resolveToDescriptorIfAny(resolutionFacade)
+                                ?.safeAs<TypeParameterDescriptor>()
+                                ?.defaultType
+                                ?.toBoundType()
+                                ?.typeVariable
+                                ?: continue
+                            declarationToTypeVariable[typeParameter] = typeVariable
+                        }
+                    }
+                    is KtCallExpression ->
+                        for (typeArgument in expression.typeArguments) {
+                            typeArgument.typeReference?.toBoundType()
+                        }
+                    is KtLambdaExpression -> {
+                        val context = expression.analyze(resolutionFacade)
+                        val returnType = expression.getType(context)?.arguments?.lastOrNull()?.type ?: return@forEachDescendantOfType
+                        val typeVariable = returnType.toBoundType()?.typeVariable ?: return@forEachDescendantOfType
+                        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
+                    }
+                }
+            }
+        }
+
+        val typeVariables =
+            (typeElementToTypeVariable.values + declarationToTypeVariable.values + typeBasedTypeVariables).distinct()
+        return InferenceContext(
+            elements,
+            typeVariables,
+            typeElementToTypeVariable,
+            declarationToTypeVariable,
+            declarationToTypeVariable.mapNotNull { (key, value) ->
+                key.resolveToDescriptorIfAny(resolutionFacade)?.let { it to value }
+            }.toMap(),
+            substitutors
+        )
+    }
+
+    abstract fun ClassReference.getState(typeElement: KtTypeElement?): State?
+}

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

@@ -0,0 +1,81 @@
+/*
+ * 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
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
+
+class DebugPrinter(private val inferenceContext: InferenceContext) {
+    private val namer = Namer(inferenceContext)
+
+    val TypeVariable.name: String
+        get() = namer.name(this)
+
+    private fun ClassReference.asString() = when (this) {
+        is DescriptorClassReference -> descriptor.name.toString()
+        is TypeParameterReference -> descriptor.name.toString()
+        is NoClassReference -> "NoClassRef"
+    }
+
+    fun BoundTypeLabel.asString(): String = when (this) {
+        is TypeVariableLabel -> typeVariable.name + "@" + typeVariable.classReference.asString()
+        is TypeParameterLabel -> typeParameter.name.asString()
+        is GenericLabel -> classReference.asString()
+        StarProjectionLabel -> "*"
+        NullLiteralLabel -> "NULL"
+        LiteralLabel -> "LIT"
+    }
+
+    fun State.asString() = when (this) {
+        State.LOWER -> "L"
+        State.UPPER -> "U"
+        State.UNKNOWN -> "?"
+    }
+
+    fun BoundType.asString(): String = buildString {
+        append(label.asString())
+        if (typeParameters.isNotEmpty()) {
+            typeParameters.joinTo(this, ", ", "<", ">") { it.boundType.asString() }
+        }
+        if (this@asString is WithForcedStateBoundType) {
+            append("!!")
+            append(forcedState.asString())
+        }
+    }
+
+    fun Constraint.asString() = when (this) {
+        is EqualsConstraint -> "${left.asString()} := ${right.asString()}"
+        is SubtypeConstraint -> "${subtype.asString()} <: ${supertype.asString()}"
+    } + " due to '$priority'"
+
+
+    private fun ConstraintBound.asString(): String = when (this) {
+        is LiteralBound -> state.toString()
+        is TypeVariableBound -> typeVariable.name
+    }
+
+    fun PsiElement.addTypeVariablesNames() {
+        val factory = KtPsiFactory(this)
+        for (typeElement in collectDescendantsOfType<KtTypeElement>()) {
+            val typeVariableName = this@DebugPrinter.inferenceContext.typeElementToTypeVariable[typeElement]?.name ?: continue
+            val comment = factory.createComment("/*$typeVariableName@*/")
+            typeElement.parent.addBefore(comment, typeElement)
+        }
+    }
+}
+
+
+private class Namer(inferenceContext: InferenceContext) {
+    val names = inferenceContext.typeVariables.mapIndexed { index, typeVariable ->
+        typeVariable to "T$index"
+    }.toMap()
+
+
+    fun name(typeVariable: TypeVariable): String =
+        names.getValue(typeVariable)
+}

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

@@ -0,0 +1,32 @@
+/*
+ * 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
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.idea.core.util.range
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.KtTypeElement
+
+data class InferenceContext(
+    val elements: List<KtElement>,
+    val typeVariables: List<TypeVariable>,
+    val typeElementToTypeVariable: Map<KtTypeElement, TypeVariable>,
+    val declarationToTypeVariable: Map<KtNamedDeclaration, TypeVariable>,
+    val declarationDescriptorToTypeVariable: Map<DeclarationDescriptor, TypeVariable>,
+    val classSubstitutions: Map<ClassDescriptor, ClassSubstitutor>
+
+) {
+    fun isInConversionScope(childCandidate: PsiElement) = when (childCandidate) {
+        is KtElement -> elements.any { element ->
+            element.containingKtFile == childCandidate.containingKtFile
+                    && element.range.contains(childCandidate.range)
+        }
+        else -> false
+    }
+}

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

@@ -0,0 +1,52 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.idea.util.application.runWriteAction
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtPsiFactory
+
+class InferenceFacade(
+    private val typeVariablesCollector: ContextCollector,
+    private val constraintsCollectorAggregator: ConstraintsCollectorAggregator,
+    private val boundTypeCalculator: BoundTypeCalculator,
+    private val stateUpdater: StateUpdater,
+    private val renderDebugTypes: Boolean = false,
+    private val printDebugConstraints: Boolean = false
+) {
+    fun runOn(elements: List<KtElement>) {
+        val inferenceContext = typeVariablesCollector.collectTypeVariables(elements)
+        val constraints = constraintsCollectorAggregator.collectConstraints(boundTypeCalculator, inferenceContext, elements)
+
+        val initialConstraints = if (renderDebugTypes) constraints.map { it.copy() } else null
+        Solver(inferenceContext, printDebugConstraints).solveConstraints(constraints)
+
+        if (renderDebugTypes) {
+            with(DebugPrinter(inferenceContext)) {
+                runWriteAction {
+                    for ((expression, boundType) in boundTypeCalculator.expressionsWithBoundType()) {
+                        val comment = KtPsiFactory(expression.project).createComment("/*${boundType.asString()}*/")
+                        expression.parent.addAfter(comment, expression)
+                    }
+                    for (element in elements) {
+                        element.addTypeVariablesNames()
+                    }
+                    for (element in elements) {
+                        val factory = KtPsiFactory(element)
+                        element.add(factory.createNewLine(lineBreaks = 2))
+                        for (constraint in initialConstraints!!) {
+                            element.add(factory.createComment("//${constraint.asString()}"))
+                            element.add(factory.createNewLine(lineBreaks = 1))
+                        }
+                    }
+                }
+            }
+        }
+        runWriteAction {
+            stateUpdater.updateStates(inferenceContext)
+        }
+    }
+}

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

@@ -3,27 +3,29 @@
  * 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.nullabilityAnalysis
+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: AnalysisContext,
+    private val analysisContext: InferenceContext,
     private val printConstraints: Boolean
 ) {
-    private val printer = Printer(analysisContext)
+    private val printer = DebugPrinter(analysisContext)
 
     private fun List<Constraint>.printDebugInfo(step: Int) =
         with(printer) {
             if (printConstraints) {
                 println("Step $step:")
-                println(listConstrains())
+                for (constraint in this@printDebugInfo) {
+                    println(constraint.asString())
+                }
                 println()
                 println("type variables:")
-                for (typeVariable in analysisContext.typeElementToTypeVariable.values) {
-                    println("${typeVariable.name} := ${typeVariable.nullability}")
+                for (typeVariable in analysisContext.typeVariables) {
+                    println("${typeVariable.name} := ${typeVariable.state}")
                 }
                 println("---------------\n")
             }
@@ -31,7 +33,7 @@ internal class Solver(
 
     fun solveConstraints(constraints: List<Constraint>) {
         val mutableConstraints = constraints.toMutableList()
-        var currentStep = ConstraintCameFrom.values().first()
+        var currentStep = ConstraintPriority.values().first()
 
         var i = 0
         do {
@@ -40,22 +42,22 @@ internal class Solver(
                 printDebugInfo(i)
                 somethingChanged = handleConstraintsWithNullableLowerBound(currentStep) || somethingChanged
                 somethingChanged = handleConstraintsWithNotNullUpperBound(currentStep) || somethingChanged
-                somethingChanged = handleEqualConstraints(currentStep) || somethingChanged
+                somethingChanged = handleEqualsConstraints(currentStep) || somethingChanged
                 somethingChanged = substituteConstraints() || somethingChanged
                 cleanConstraints()
             }
 
 
             if (!somethingChanged) {
-                if (currentStep.ordinal < ConstraintCameFrom.values().lastIndex) {
-                    currentStep = ConstraintCameFrom.values()[currentStep.ordinal + 1]
+                if (currentStep.ordinal < ConstraintPriority.values().lastIndex) {
+                    currentStep = ConstraintPriority.values()[currentStep.ordinal + 1]
                     somethingChanged = true
                 }
             }
             if (!somethingChanged) {
                 val typeVariable = mutableConstraints.getTypeVariableAsEqualsOrUpperBound()
                 if (typeVariable != null) {
-                    typeVariable.setNullabilityIfNotFixed(Nullability.NOT_NULL)
+                    typeVariable.setStateIfNotFixed(State.LOWER)
                     somethingChanged = true
                 }
             }
@@ -65,21 +67,14 @@ internal class Solver(
 
 
     private fun MutableList<Constraint>.cleanConstraints() {
-        val newConstraints =
-            distinct()
-                .filterNot { constraint ->
-                    constraint is SubtypeConstraint
-                            && constraint.lowerBound is LiteralBound
-                            && constraint.upperBound is LiteralBound
-                }
-
-        if (newConstraints.size < size) {
-            clear()
-            addAll(newConstraints)
+        removeIf { constraint ->
+            constraint is SubtypeConstraint
+                    && constraint.subtype is LiteralBound
+                    && constraint.supertype is LiteralBound
         }
     }
 
-    private fun MutableList<Constraint>.handleConstraintsWithNullableLowerBound(step: ConstraintCameFrom): Boolean {
+    private fun MutableList<Constraint>.handleConstraintsWithNullableLowerBound(step: ConstraintPriority): Boolean {
         var somethingChanged = false
         val nullableConstraints = getConstraintsWithNullableLowerBound(step)
         if (nullableConstraints.isNotEmpty()) {
@@ -87,14 +82,14 @@ internal class Solver(
             for ((_, upperBound) in nullableConstraints) {
                 if (upperBound is TypeVariableBound) {
                     somethingChanged = true
-                    upperBound.typeVariable.setNullabilityIfNotFixed(Nullability.NULLABLE)
+                    upperBound.typeVariable.setStateIfNotFixed(State.UPPER)
                 }
             }
         }
         return somethingChanged
     }
 
-    private fun MutableList<Constraint>.handleConstraintsWithNotNullUpperBound(step: ConstraintCameFrom): Boolean {
+    private fun MutableList<Constraint>.handleConstraintsWithNotNullUpperBound(step: ConstraintPriority): Boolean {
         var somethingChanged = false
         val nullableConstraints = getConstraintsWithNotNullUpperBound(step)
         if (nullableConstraints.isNotEmpty()) {
@@ -102,37 +97,36 @@ internal class Solver(
             for ((lowerBound, _) in nullableConstraints) {
                 if (lowerBound is TypeVariableBound) {
                     somethingChanged = true
-                    lowerBound.typeVariable.setNullabilityIfNotFixed(Nullability.NOT_NULL)
+                    lowerBound.typeVariable.setStateIfNotFixed(State.LOWER)
                 }
             }
         }
         return somethingChanged
     }
 
-    private fun ConstraintBound.fixedNullability(): Nullability? =
-        when {
-            this is LiteralBound -> nullability
-            this is TypeVariableBound && typeVariable.isFixed -> typeVariable.nullability
-            else -> null
-        }
+    private fun ConstraintBound.fixedState(): State? = when {
+        this is LiteralBound -> state
+        this is TypeVariableBound && typeVariable.isFixed -> typeVariable.state
+        else -> null
+    }
 
-    private fun MutableList<Constraint>.handleEqualConstraints(step: ConstraintCameFrom): Boolean {
+    private fun MutableList<Constraint>.handleEqualsConstraints(step: ConstraintPriority): Boolean {
         var somethingChanged = false
-        val equalsConstraints = filterIsInstance<EqualConstraint>().filter { it.cameFrom <= step }
+        val equalsConstraints = filterIsInstance<EqualsConstraint>().filter { it.priority <= step }
         if (equalsConstraints.isNotEmpty()) {
             for (constraint in equalsConstraints) {
                 val (leftBound, rightBound) = constraint
                 when {
-                    leftBound is TypeVariableBound && rightBound.fixedNullability() != null -> {
+                    leftBound is TypeVariableBound && rightBound.fixedState() != null -> {
                         this -= constraint
                         somethingChanged = true
-                        leftBound.typeVariable.setNullabilityIfNotFixed(rightBound.fixedNullability()!!)
+                        leftBound.typeVariable.setStateIfNotFixed(rightBound.fixedState()!!)
                     }
 
-                    rightBound is TypeVariableBound && leftBound.fixedNullability() != null -> {
+                    rightBound is TypeVariableBound && leftBound.fixedState() != null -> {
                         this -= constraint
                         somethingChanged = true
-                        rightBound.typeVariable.setNullabilityIfNotFixed(leftBound.fixedNullability()!!)
+                        rightBound.typeVariable.setStateIfNotFixed(leftBound.fixedState()!!)
                     }
                 }
             }
@@ -148,39 +142,38 @@ internal class Solver(
                 val (lower, upper) = constraint
                 if (lower is TypeVariableBound && lower.typeVariable.isFixed) {
                     somethingChanged = true
-                    constraint.lowerBound = LiteralBound(lower.typeVariable.nullability)
+                    constraint.subtype = lower.typeVariable.state.constraintBound
                 }
                 if (upper is TypeVariableBound && upper.typeVariable.isFixed) {
                     somethingChanged = true
-                    constraint.upperBound = LiteralBound(upper.typeVariable.nullability)
+                    constraint.supertype = upper.typeVariable.state.constraintBound
                 }
             }
         }
         return somethingChanged
     }
 
-    private fun List<Constraint>.getConstraintsWithNullableLowerBound(cameFrom: ConstraintCameFrom) =
+    private fun List<Constraint>.getConstraintsWithNullableLowerBound(priority: ConstraintPriority) =
         filterIsInstance<SubtypeConstraint>().filter { constraint ->
-            constraint.cameFrom <= cameFrom
-                    && constraint.lowerBound.safeAs<LiteralBound>()?.nullability == Nullability.NULLABLE
+            constraint.priority <= priority
+                    && constraint.subtype.safeAs<LiteralBound>()?.state == State.UPPER
         }
 
-    private fun List<Constraint>.getConstraintsWithNotNullUpperBound(cameFrom: ConstraintCameFrom) =
+    private fun List<Constraint>.getConstraintsWithNotNullUpperBound(priority: ConstraintPriority) =
         filterIsInstance<SubtypeConstraint>().filter { constraint ->
-            constraint.cameFrom <= cameFrom
-                    && constraint.upperBound.safeAs<LiteralBound>()?.nullability == Nullability.NOT_NULL
+            constraint.priority <= priority
+                    && constraint.supertype.safeAs<LiteralBound>()?.state == State.LOWER
         }
 
 
     private fun List<Constraint>.getTypeVariableAsEqualsOrUpperBound(): TypeVariable? =
         asSequence().filterIsInstance<SubtypeConstraint>()
-            .map { it.upperBound }
+            .map { it.supertype }
             .firstIsInstanceOrNull<TypeVariableBound>()
             ?.typeVariable
-            ?: asSequence().filterIsInstance<EqualConstraint>()
-                .flatMap { sequenceOf(it.leftBound, it.rightBound) }
+            ?: asSequence().filterIsInstance<EqualsConstraint>()
+                .flatMap { sequenceOf(it.left, it.right) }
                 .firstIsInstanceOrNull<TypeVariableBound>()
                 ?.typeVariable
-
 }
 

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

@@ -0,0 +1,12 @@
+/*
+ * 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
+
+enum class State {
+    LOWER,
+    UPPER,
+    UNKNOWN
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/inference/common/StateUpdater.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 StateUpdater {
+    abstract fun updateStates(inferenceContext: InferenceContext)
+}

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

@@ -0,0 +1,58 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.*
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.psiUtil.forEachDescendantOfType
+import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+abstract class SuperFunctionsProvider {
+    abstract fun provideSuperFunctionDescriptors(function: KtFunction): List<FunctionDescriptor>?
+    lateinit var inferenceContext: InferenceContext
+}
+
+class ResolveSuperFunctionsProvider(private val resolutionFacade: ResolutionFacade) : SuperFunctionsProvider() {
+    override fun provideSuperFunctionDescriptors(function: KtFunction): List<FunctionDescriptor>? =
+        function.resolveToDescriptorIfAny(resolutionFacade)
+            ?.safeAs<FunctionDescriptor>()
+            ?.original
+            ?.overriddenDescriptors
+            ?.toList()
+}
+
+class ByInfoSuperFunctionsProvider(
+    private val resolutionFacade: ResolutionFacade,
+    private val converterContext: NewJ2kConverterContext
+) : SuperFunctionsProvider() {
+
+    private val labelToFunction by lazy(LazyThreadSafetyMode.NONE) {
+        val functions = mutableMapOf<JKElementInfoLabel, KtNamedFunction>()
+        for (element in inferenceContext.elements) {
+            element.forEachDescendantOfType<KtNamedFunction> { function ->
+                val label = function.nameIdentifier?.getLabel() ?: return@forEachDescendantOfType
+                functions += label to function
+            }
+        }
+        functions
+    }
+
+    override fun provideSuperFunctionDescriptors(function: KtFunction): List<FunctionDescriptor>? =
+        function.nameIdentifier?.elementInfo(converterContext)?.firstIsInstanceOrNull<FunctionInfo>()
+            ?.superFunctions
+            ?.mapNotNull { superFunction ->
+                when (superFunction) {
+                    is ExternalSuperFunctionInfo -> superFunction.descriptor
+                    is InternalSuperFunctionInfo ->
+                        labelToFunction[superFunction.label]?.resolveToDescriptorIfAny(resolutionFacade)
+                }
+            }
+}

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

@@ -0,0 +1,79 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.types.Variance
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+sealed class ClassReference
+class DescriptorClassReference(val descriptor: ClassDescriptor) : ClassReference()
+class TypeParameterReference(val descriptor: TypeParameterDescriptor) : ClassReference()
+object NoClassReference : ClassReference()
+
+val ClassDescriptor.classReference: DescriptorClassReference
+    get() = DescriptorClassReference(this)
+
+val ClassReference.descriptor: ClassDescriptor?
+    get() = safeAs<DescriptorClassReference>()?.descriptor
+
+class TypeParameter(val boundType: BoundType, val variance: Variance)
+
+sealed class BoundType {
+    abstract val label: BoundTypeLabel
+    abstract val typeParameters: List<TypeParameter>
+
+    companion object {
+        val LITERAL = BoundTypeImpl(LiteralLabel, emptyList())
+        val STAR_PROJECTION = BoundTypeImpl(StarProjectionLabel, emptyList())
+        val NULL = BoundTypeImpl(NullLiteralLabel, emptyList())
+    }
+}
+
+class BoundTypeImpl(
+    override val label: BoundTypeLabel,
+    override val typeParameters: List<TypeParameter>
+) : BoundType()
+
+
+class WithForcedStateBoundType(
+    val original: BoundType,
+    val forcedState: State
+) : BoundType() {
+    override val label: BoundTypeLabel
+        get() = original.label
+    override val typeParameters: List<TypeParameter>
+        get() = original.typeParameters
+}
+
+fun BoundType.withEnhancementFrom(from: BoundType) = when (from) {
+    is BoundTypeImpl -> this
+    is WithForcedStateBoundType -> WithForcedStateBoundType(this, from.forcedState)
+}
+
+fun BoundType.enhanceWith(state: State?) =
+    if (state != null) WithForcedStateBoundType(this, state)
+    else this
+
+sealed class BoundTypeLabel
+
+class TypeVariableLabel(val typeVariable: TypeVariable) : BoundTypeLabel()
+class TypeParameterLabel(val typeParameter: TypeParameterDescriptor) : BoundTypeLabel()
+class GenericLabel(val classReference: ClassReference) : BoundTypeLabel()
+object NullLiteralLabel : BoundTypeLabel()
+object LiteralLabel : BoundTypeLabel()
+object StarProjectionLabel : BoundTypeLabel()
+
+
+fun TypeVariable.asBoundType(): BoundType =
+    BoundTypeImpl(TypeVariableLabel(this), typeParameters)
+
+val BoundType.typeVariable: TypeVariable?
+    get() = label.safeAs<TypeVariableLabel>()?.typeVariable
+
+val BoundType.isReferenceToClass: Boolean
+    get() = label is TypeVariableLabel || label is GenericLabel

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

@@ -0,0 +1,112 @@
+/*
+ * 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.collectors
+
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.descriptors.ParameterDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.inference.common.*
+import org.jetbrains.kotlin.psi.KtCallElement
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
+import org.jetbrains.kotlin.resolve.calls.components.isVararg
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+class CallExpressionConstraintCollector : ConstraintsCollector() {
+    override fun ConstraintBuilder.collectConstraints(
+        element: KtElement,
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        resolutionFacade: ResolutionFacade
+    ) {
+        if (element !is KtCallElement) return
+        val call = element.resolveToCall(resolutionFacade) ?: return
+        val originalDescriptor = call.candidateDescriptor.safeAs<FunctionDescriptor>()?.original ?: return
+        val valueArguments = call.valueArgumentsByIndex.orEmpty()
+        val typeParameterBindings =
+            call.candidateDescriptor.typeParameters.zip(call.call.typeArguments) { typeParameter, typeArgument ->
+                typeArgument.typeReference?.typeElement?.let {
+                    inferenceContext.typeElementToTypeVariable[it]
+                }?.let { typeVariable ->
+                    typeParameter?.let { it to typeVariable }
+                }
+            }.filterNotNull().toMap()
+
+        val receiverExpressionBoundType = element.getQualifiedExpressionForSelector()
+            ?.receiverExpression
+            ?.boundType(inferenceContext)
+
+        fun KotlinType.contextBoundType() = boundType(
+            contextBoundType = receiverExpressionBoundType,
+            call = call,
+            inferenceContext = inferenceContext
+        )
+
+        fun BoundType.substituteTypeParameters(): BoundType =
+            BoundTypeImpl(
+                when (label) {
+                    is TypeVariableLabel -> (label as TypeVariableLabel)
+                        .typeVariable
+                        .safeAs<TypeElementBasedTypeVariable>()
+                        ?.typeElement
+                        ?.safeAs<TypeParameterElementData>()
+                        ?.let { typeParameterData ->
+                            typeParameterBindings[typeParameterData.typeParameterDescriptor]
+                        }?.let { typeVariable ->
+                            TypeVariableLabel(typeVariable)
+                        } ?: label
+                    else -> label
+                },
+                typeParameters.map { typeParameter ->
+                    TypeParameter(
+                        typeParameter.boundType.substituteTypeParameters(),
+                        typeParameter.variance
+                    )
+                }
+            ).withEnhancementFrom(this)
+
+        fun ParameterDescriptor.boundType() =
+            inferenceContext.declarationDescriptorToTypeVariable[this]
+                ?.asBoundType()
+                ?.substituteTypeParameters()
+                ?: original.type.contextBoundType()
+
+
+        if (receiverExpressionBoundType != null) run {
+            val receiverBoundType =
+                (originalDescriptor.extensionReceiverParameter ?: originalDescriptor.dispatchReceiverParameter)?.boundType()
+                    ?: return@run
+            receiverExpressionBoundType.isSubtypeOf(receiverBoundType, ConstraintPriority.RECEIVER_PARAMETER)
+        }
+
+        val parameterToArgument = call.candidateDescriptor.valueParameters.let { parameters ->
+            valueArguments.mapIndexed { i, arguments ->
+                val parameter = parameters[i]
+                val parameterBoundType = parameter.boundType()
+
+                val parameterBoundTypeConsideringVararg =
+                    if (parameter.isVararg && KotlinBuiltIns.isArrayOrPrimitiveArray(parameter.type)) {
+                        if (KotlinBuiltIns.isPrimitiveArray(parameter.type))
+                            BoundTypeImpl(
+                                GenericLabel(NoClassReference),//not important as it just a primitive type
+                                emptyList()
+                            ) else parameterBoundType.typeParameters[0].boundType
+                    } else parameterBoundType
+                arguments.arguments.map { argument ->
+                    parameterBoundTypeConsideringVararg to argument
+                }
+            }
+        }.flatten()
+
+        for ((parameter, argument) in parameterToArgument) {
+            val argumentExpression = argument.getArgumentExpression() ?: continue
+            argumentExpression.isSubtypeOf(parameter, ConstraintPriority.PARAMETER)
+        }
+    }
+}

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

@@ -0,0 +1,135 @@
+/*
+ * 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.collectors
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.inference.common.BoundTypeCalculator
+import org.jetbrains.kotlin.nj2k.inference.common.ConstraintBuilder
+import org.jetbrains.kotlin.nj2k.inference.common.ConstraintPriority
+import org.jetbrains.kotlin.nj2k.inference.common.InferenceContext
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.asAssignment
+import org.jetbrains.kotlin.resolve.bindingContextUtil.getTargetFunction
+import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
+import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+class CommonConstraintsCollector : ConstraintsCollector() {
+    override fun ConstraintBuilder.collectConstraints(
+        element: KtElement,
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        resolutionFacade: ResolutionFacade
+    ) = with(boundTypeCalculator) {
+        when {
+            element is KtBinaryExpressionWithTypeRHS && KtPsiUtil.isUnsafeCast(element) -> {
+                element.right?.typeElement?.let { inferenceContext.typeElementToTypeVariable[it] }?.also { typeVariable ->
+                    element.left.isSubtypeOf(typeVariable, ConstraintPriority.ASSIGNMENT)
+                }
+            }
+
+            element is KtBinaryExpression && element.asAssignment() != null -> {
+                element.right?.isSubtypeOf(element.left ?: return, ConstraintPriority.ASSIGNMENT)
+            }
+
+
+            element is KtVariableDeclaration -> {
+                inferenceContext.declarationToTypeVariable[element]?.also { typeVariable ->
+                    element.initializer?.isSubtypeOf(typeVariable, ConstraintPriority.INITIALIZER)
+                }
+            }
+
+            element is KtParameter -> {
+                inferenceContext.declarationToTypeVariable[element]?.also { typeVariable ->
+                    element.defaultValue?.isSubtypeOf(
+                        typeVariable,
+                        ConstraintPriority.INITIALIZER
+                    )
+                }
+            }
+
+            element is KtReturnExpression -> {
+                val functionTypeVariable = element.getTargetFunction(element.analyze(resolutionFacade))
+                    ?.resolveToDescriptorIfAny(resolutionFacade)
+                    ?.let { functionDescriptor ->
+                        inferenceContext.declarationDescriptorToTypeVariable[functionDescriptor]
+                    } ?: return
+                element.returnedExpression?.isSubtypeOf(
+                    functionTypeVariable,
+                    ConstraintPriority.RETURN
+                )
+            }
+
+            element is KtReturnExpression -> {
+                val targetTypeVariable =
+                    element.getTargetFunction(element.analyze(resolutionFacade))?.let { function ->
+                        inferenceContext.declarationToTypeVariable[function]
+                    }
+                if (targetTypeVariable != null) {
+                    element.returnedExpression?.isSubtypeOf(
+                        targetTypeVariable,
+                        ConstraintPriority.RETURN
+                    )
+                }
+            }
+
+            element is KtLambdaExpression -> {
+                val targetTypeVariable =
+                    inferenceContext.declarationToTypeVariable[element.functionLiteral] ?: return
+                element.functionLiteral.bodyExpression?.statements?.lastOrNull()
+                    ?.takeIf { it !is KtReturnExpression }
+                    ?.also { implicitReturn ->
+                        implicitReturn.isSubtypeOf(
+                            targetTypeVariable,
+                            ConstraintPriority.RETURN
+                        )
+                    }
+            }
+
+            element is KtForExpression -> {
+                val loopParameterTypeVariable =
+                    element.loopParameter?.typeReference?.typeElement?.let { typeElement ->
+                        inferenceContext.typeElementToTypeVariable[typeElement]
+                    }
+                if (loopParameterTypeVariable != null) {
+                    val loopRangeBoundType = element.loopRange?.boundType(inferenceContext) ?: return
+                    val boundType =
+                        element.loopRangeElementType(resolutionFacade)
+                            ?.boundType(
+                                contextBoundType = loopRangeBoundType,
+                                inferenceContext = inferenceContext
+                            ) ?: return
+                    loopParameterTypeVariable.isSubtypeOf(
+                        boundType.typeParameters.firstOrNull()?.boundType ?: return,
+                        ConstraintPriority.ASSIGNMENT
+                    )
+                }
+            }
+        }
+        Unit
+    }
+
+    private fun KtForExpression.loopRangeElementType(resolutionFacade: ResolutionFacade): KotlinType? {
+        val loopRangeType = loopRange?.getType(analyze(resolutionFacade)) ?: return null
+        return loopRangeType
+            .constructor
+            .declarationDescriptor
+            ?.safeAs<ClassDescriptor>()
+            ?.getMemberScope(loopRangeType.arguments)
+            ?.getDescriptorsFiltered(DescriptorKindFilter.FUNCTIONS) {
+                it.asString() == "iterator"
+            }?.filterIsInstance<FunctionDescriptor>()
+            ?.firstOrNull { it.valueParameters.isEmpty() }
+            ?.original
+            ?.returnType
+    }
+}

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

@@ -0,0 +1,21 @@
+/*
+ * 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.collectors
+
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.inference.common.BoundTypeCalculator
+import org.jetbrains.kotlin.nj2k.inference.common.ConstraintBuilder
+import org.jetbrains.kotlin.nj2k.inference.common.InferenceContext
+import org.jetbrains.kotlin.psi.KtElement
+
+abstract class ConstraintsCollector {
+    abstract fun ConstraintBuilder.collectConstraints(
+        element: KtElement,
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        resolutionFacade: ResolutionFacade
+    )
+}

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

@@ -0,0 +1,105 @@
+/*
+ * 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.collectors
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
+import org.jetbrains.kotlin.nj2k.inference.common.*
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+class FunctionConstraintsCollector(
+    private val superFunctionsProvider: SuperFunctionsProvider
+) : ConstraintsCollector() {
+    override fun ConstraintBuilder.collectConstraints(
+        element: KtElement,
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        resolutionFacade: ResolutionFacade
+    ) {
+        if (element !is KtFunction) return
+        superFunctionsProvider.inferenceContext = inferenceContext
+        val ktClass = element.containingClassOrObject ?: return
+        val classDescriptor = ktClass.resolveToDescriptorIfAny(resolutionFacade) ?: return
+
+        val superFunctions = superFunctionsProvider.provideSuperFunctionDescriptors(element) ?: return
+        val substitutor = inferenceContext.classSubstitutions[classDescriptor] ?: return
+
+        for (superFunction in superFunctions) {
+            val superClass = superFunction.containingDeclaration as? ClassDescriptor ?: continue
+            val superFunctionPsi = superFunction.original.findPsi() as? KtNamedFunction
+
+            run {
+                collectTypeConstraints(
+                    element.typeReference?.typeElement ?: return@run,
+                    superFunction.original.returnType ?: return@run,
+                    superFunctionPsi?.typeReference?.typeElement,
+                    substitutor,
+                    superClass,
+                    inferenceContext
+                )
+            }
+
+            for (parameterIndex in element.valueParameters.indices) {
+                collectTypeConstraints(
+                    element.valueParameters.getOrNull(parameterIndex)?.typeReference?.typeElement ?: continue,
+                    superFunction.valueParameters.getOrNull(parameterIndex)?.original?.type ?: continue,
+                    superFunctionPsi?.valueParameters?.getOrNull(parameterIndex)?.typeReference?.typeElement,
+                    substitutor,
+                    superClass,
+                    inferenceContext
+                )
+            }
+        }
+    }
+
+    private fun ConstraintBuilder.collectTypeConstraints(
+        typeElement: KtTypeElement,
+        superType: KotlinType,
+        superTypeElement: KtTypeElement?,
+        substitutor: ClassSubstitutor,
+        superClass: ClassDescriptor,
+        inferenceContext: InferenceContext
+    ) {
+        val usedTypeVariables = hashSetOf<TypeVariable>()
+        val substitutions = calculateTypeSubstitutions(typeElement, superType) ?: return
+        for ((innerTypeElement, innerTypeParameter) in substitutions) {
+            val superEntryTypeElement = substitutor[superClass, innerTypeParameter] ?: continue
+            innerTypeElement.isTheSameTypeAs(superEntryTypeElement, ConstraintPriority.SUPER_DECLARATION)
+
+            inferenceContext.typeElementToTypeVariable[innerTypeElement]?.also { usedTypeVariables += it }
+        }
+        val superTypeVariable = superTypeElement?.let { inferenceContext.typeElementToTypeVariable[it] }
+        if (superTypeVariable != null) {
+            superTypeVariable.isTheSameTypeAs(typeElement, ConstraintPriority.SUPER_DECLARATION, usedTypeVariables)
+        } else {
+            superType.boundType(forceEnhance = true, inferenceContext = inferenceContext)
+                .isTheSameTypeAs(typeElement, ConstraintPriority.SUPER_DECLARATION, usedTypeVariables)
+        }
+
+    }
+
+    private fun calculateTypeSubstitutions(
+        typeElement: KtTypeElement,
+        superType: KotlinType
+    ): List<Pair<KtTypeElement, TypeParameterDescriptor>>? {
+        val substitution = superType.constructor.declarationDescriptor
+            ?.safeAs<TypeParameterDescriptor>()?.let { typeElement to it }
+        return typeElement.typeArgumentsAsTypes.zip(superType.arguments)
+            .flatMap { (argumentTypeElement, argumentType) ->
+                calculateTypeSubstitutions(argumentTypeElement?.typeElement ?: return null, argumentType.type) ?: return null
+            } + listOfNotNull(substitution)
+    }
+
+}

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

@@ -0,0 +1,94 @@
+/*
+ * 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
+
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.types.KotlinType
+
+sealed class TypeVariable {
+    abstract val classReference: ClassReference
+    abstract val typeParameters: List<TypeParameter>
+    abstract var state: State
+}
+
+sealed class TypeElementData {
+    abstract val typeElement: KtTypeElement
+}
+
+data class TypeElementDataImpl(override val typeElement: KtTypeElement) : TypeElementData()
+data class TypeParameterElementData(
+    override val typeElement: KtTypeElement,
+    val typeParameterDescriptor: TypeParameterDescriptor
+) : TypeElementData()
+
+data class TypeElementBasedTypeVariable(
+    override val classReference: ClassReference,
+    override val typeParameters: List<TypeParameter>,
+    val typeElement: TypeElementData,
+    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 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(
+    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
+    }
+}
+
+val TypeVariable.isFixed: Boolean
+    get() = state != State.UNKNOWN
+
+fun TypeVariable.setStateIfNotFixed(newState: State) {
+    if (!isFixed) {
+        state = newState
+    }
+}
+

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

@@ -0,0 +1,30 @@
+/*
+ * 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
+
+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.psi.KtTypeProjection
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+fun PsiElement.getLabel(): JKElementInfoLabel? =
+    prevSibling
+        ?.safeAs<PsiComment>()
+        ?.text
+        ?.asLabel()
+        ?: parent
+            ?.safeAs<KtTypeProjection>()
+            ?.getLabel()
+
+
+fun PsiElement.elementInfo(converterContext: NewJ2kConverterContext): List<JKElementInfo>? =
+    getLabel()?.let { label ->
+        converterContext.elementsInfoStorage.getInfoForLabel(label)
+    }

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

@@ -0,0 +1,117 @@
+/*
+ * 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.ConstructorDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
+import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isNullExpression
+import org.jetbrains.kotlin.idea.references.mainReference
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.idea.resolve.frontendService
+import org.jetbrains.kotlin.nj2k.inference.common.*
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.calls.callUtil.getType
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValue
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
+import org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability
+import org.jetbrains.kotlin.resolve.jvm.checkers.mustNotBeNull
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.isNullable
+import org.jetbrains.kotlin.util.javaslang.getOrNull
+
+class NullabilityBoundTypeEnhancer(private val resolutionFacade: ResolutionFacade) : BoundTypeEnhancer() {
+    override fun enhance(
+        expression: KtExpression,
+        boundType: BoundType,
+        inferenceContext: InferenceContext
+    ): BoundType {
+        return when {
+            expression.isNullExpression() ->
+                WithForcedStateBoundType(boundType, State.UPPER)
+            expression is KtCallExpression -> enhanceCallExpression(expression, boundType, inferenceContext)
+            expression is KtQualifiedExpression && expression.selectorExpression is KtCallExpression ->
+                enhanceCallExpression(expression.selectorExpression as KtCallExpression, boundType, inferenceContext)
+            expression is KtNameReferenceExpression ->
+                boundType.enhanceWith(expression.smartCastEnhancement())
+            expression is KtLambdaExpression ->
+                WithForcedStateBoundType(boundType, State.LOWER)
+            else -> boundType
+        }
+    }
+
+    private fun enhanceCallExpression(
+        expression: KtCallExpression,
+        boundType: BoundType,
+        inferenceContext: InferenceContext
+    ): BoundType {
+        if (expression.resolveToCall(resolutionFacade)?.candidateDescriptor is ConstructorDescriptor) {
+            return WithForcedStateBoundType(boundType, State.LOWER)
+        }
+
+        val resolved = expression.calleeExpression?.mainReference?.resolve() ?: return boundType
+        if (inferenceContext.isInConversionScope(resolved)) return boundType
+        return boundType.enhanceWith(expression.getExternallyAnnotatedForcedState())
+    }
+
+    override fun enhanceKotlinType(
+        type: KotlinType,
+        boundType: BoundType,
+        allowLowerEnhancement: Boolean,
+        inferenceContext: InferenceContext
+    ): BoundType {
+        if (type.arguments.size != boundType.typeParameters.size) return boundType
+        val inner = BoundTypeImpl(
+            boundType.label,
+            boundType.typeParameters.zip(type.arguments) { typeParameter, typeArgument ->
+                TypeParameter(
+                    enhanceKotlinType(
+                        typeArgument.type,
+                        typeParameter.boundType,
+                        allowLowerEnhancement,
+                        inferenceContext
+                    ),
+                    typeParameter.variance
+                )
+            }
+        )
+        val enhancement = when {
+            type.isMarkedNullable -> State.UPPER
+            allowLowerEnhancement -> State.LOWER
+            else -> null
+        }
+        return inner.enhanceWith(enhancement)
+    }
+
+    private fun KtReferenceExpression.smartCastEnhancement() = analyzeExpressionUponTheTypeInfo { dataFlowValue, dataFlowInfo, _ ->
+        if (dataFlowInfo.completeNullabilityInfo.get(dataFlowValue)?.getOrNull() == Nullability.NOT_NULL) State.LOWER
+        else null
+    }
+
+    private inline fun KtExpression.analyzeExpressionUponTheTypeInfo(analyzer: (DataFlowValue, DataFlowInfo, KotlinType) -> State?): State? {
+        val bindingContext = analyze(resolutionFacade)
+        val type = getType(bindingContext) ?: return null
+
+        val dataFlowValue = resolutionFacade.frontendService<DataFlowValueFactory>()
+            .createDataFlowValue(this, type, bindingContext, resolutionFacade.moduleDescriptor)
+        val dataFlowInfo = bindingContext[BindingContext.EXPRESSION_TYPE_INFO, this]?.dataFlowInfo ?: return null
+        return analyzer(dataFlowValue, dataFlowInfo, type)
+    }
+
+    private fun KtExpression.getExternallyAnnotatedForcedState() = analyzeExpressionUponTheTypeInfo { dataFlowValue, dataFlowInfo, type ->
+        if (!type.isNullable()) return@analyzeExpressionUponTheTypeInfo State.LOWER
+        when {
+            dataFlowInfo.completeNullabilityInfo.get(dataFlowValue)?.getOrNull() == Nullability.NOT_NULL -> State.LOWER
+            type.isExternallyAnnotatedNotNull(dataFlowInfo, dataFlowValue) -> State.LOWER
+            else -> null
+        }
+    }
+
+    private fun KotlinType.isExternallyAnnotatedNotNull(dataFlowInfo: DataFlowInfo, dataFlowValue: DataFlowValue): Boolean =
+        mustNotBeNull()?.isFromJava == true && dataFlowInfo.getStableNullability(dataFlowValue).canBeNull()
+}

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

@@ -0,0 +1,55 @@
+/*
+ * 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.idea.intentions.branchedTransformations.isNullExpression
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
+import org.jetbrains.kotlin.nj2k.inference.common.*
+import org.jetbrains.kotlin.nj2k.inference.common.collectors.ConstraintsCollector
+import org.jetbrains.kotlin.psi.*
+
+class NullabilityConstraintsCollector : ConstraintsCollector() {
+    override fun ConstraintBuilder.collectConstraints(
+        element: KtElement,
+        boundTypeCalculator: BoundTypeCalculator,
+        inferenceContext: InferenceContext,
+        resolutionFacade: ResolutionFacade
+    ) = with(boundTypeCalculator) {
+        when {
+            element is KtBinaryExpression &&
+                    (element.left?.isNullExpression() == true
+                            || element.right?.isNullExpression() == true) -> {
+                val notNullOperand =
+                    if (element.left?.isNullExpression() == true) element.right
+                    else element.left
+                notNullOperand?.isTheSameTypeAs(State.UPPER, ConstraintPriority.COMPARE_WITH_NULL)
+            }
+            element is KtQualifiedExpression -> {
+                element.receiverExpression.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+
+            element is KtForExpression -> {
+                element.loopRange?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+
+            element is KtWhileExpressionBase -> {
+                element.condition?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+
+            element is KtIfExpression -> {
+                element.condition?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+            element is KtValueArgument && element.isSpread -> {
+                element.getArgumentExpression()?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+            element is KtBinaryExpression && !KtPsiUtil.isAssignment(element) -> {
+                element.left?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+                element.right?.isTheSameTypeAs(State.LOWER, ConstraintPriority.USE_AS_RECEIVER)
+            }
+        }
+        Unit
+    }
+}

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

@@ -0,0 +1,43 @@
+/*
+ * 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.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.psi.KtNullableType
+import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
+
+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
+        }
+    }
+
+
+    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/NullabilityStateUpdater.kt

@@ -0,0 +1,56 @@
+/*
+ * 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.*
+import org.jetbrains.kotlin.psi.KtNullableType
+import org.jetbrains.kotlin.psi.KtPsiFactory
+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)
+                    }
+                }
+            }
+        }
+    }
+
+    private fun TypeElementBasedTypeVariable.changeState(toNullable: Boolean) {
+        changeState(typeElement.typeElement, toNullable)
+    }
+
+    companion object {
+        fun changeState(typeElement: KtTypeElement, toNullable: Boolean) {
+            val factory = KtPsiFactory(typeElement)
+            if (typeElement is KtNullableType && !toNullable) {
+                typeElement.replace(factory.createType(typeElement.innerType?.text ?: return).typeElement ?: return)
+            }
+            if (typeElement !is KtNullableType && toNullable) {
+                typeElement.replace(factory.createType("${typeElement.text}?").typeElement ?: return)
+            }
+        }
+    }
+
+}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/BoundTypeStorage.kt

@@ -1,203 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.psi.PsiComment
-import org.jetbrains.kotlin.descriptors.CallableDescriptor
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
-import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.idea.references.mainReference
-import org.jetbrains.kotlin.nj2k.postProcessing.resolve
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.getNextSiblingIgnoringWhitespace
-import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
-import org.jetbrains.kotlin.resolve.calls.callUtil.getCalleeExpressionIfAny
-import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
-import org.jetbrains.kotlin.resolve.calls.callUtil.getType
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.types.Variance
-import org.jetbrains.kotlin.types.isNullable
-import org.jetbrains.kotlin.types.typeUtil.builtIns
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-internal class BoundTypeStorage(private val analysisAnalysisContext: AnalysisContext, private val printConstraints: Boolean) {
-    private val cache = mutableMapOf<KtExpression, BoundType>()
-    private val printer = Printer(analysisAnalysisContext)
-
-    fun boundTypeFor(expression: KtExpression): BoundType =
-        cache.getOrPut(expression) {
-            val boundType =
-                when (expression) {
-                    is KtParenthesizedExpression -> expression.expression?.let { boundTypeFor(it) }
-                    is KtQualifiedExpression ->
-                        expression.selectorExpression?.toBoundType(
-                            boundTypeFor(expression.receiverExpression)
-                        )
-                    is KtLabeledExpression -> expression.baseExpression?.let { boundTypeFor(it) }
-                    is KtLambdaExpression -> lambdaBoundType(expression)
-                    else -> expression.getQualifiedExpressionForSelector()?.let { boundTypeFor(it) }
-                } ?: expression.toBoundType(null)
-                ?: LiteralBoundType(expression.isNullable())
-
-            if (printConstraints) {
-                if (expression.getNextSiblingIgnoringWhitespace() !is PsiComment) {
-                    val comment = with(printer) {
-                        KtPsiFactory(expression.project).createComment("/*${boundType.asString()}*/")
-                    }
-                    expression.parent.addAfter(comment, expression)
-                }
-            }
-            boundType.withForcedNullability(expression.getForcedNullability())
-        }
-
-    private fun lambdaBoundType(lambda: KtLambdaExpression): BoundType? {
-        val builtIns = lambda.getType(lambda.analyze())?.builtIns ?: return null
-
-        val descriptor = builtIns.getFunction(lambda.valueParameters.size)
-        val parameterBoundTypes = lambda.valueParameters.map { parameter ->
-            parameter.typeReference?.typeElement?.let { typeElement ->
-                analysisAnalysisContext.typeElementToTypeVariable[typeElement]
-            }?.let {
-                BoundTypeTypeParameter(TypeVariableBoundType(it), Variance.IN_VARIANCE)
-            } ?: return null
-        }
-        val returnBoundType =
-            BoundTypeTypeParameter(
-                TypeVariableBoundType(
-                    analysisAnalysisContext.declarationToTypeVariable[lambda.functionLiteral] ?: return null
-                ),
-                Variance.OUT_VARIANCE
-            )
-        return GenericBoundType(
-            DescriptorClassReference(descriptor),
-            parameterBoundTypes + returnBoundType,
-            forcedNullabilityTo = null,
-            isNull = false
-        )
-    }
-
-
-    fun boundTypeForType(
-        type: KotlinType,
-        contextBoundType: BoundType?,
-        typeParameterDescriptors: Map<TypeParameterDescriptor, TypeVariable>
-    ): BoundType? =
-        type.toBoundType(contextBoundType, typeParameterDescriptors)
-
-    private fun KtExpression.resolveToTypeVariable(): TypeVariable? =
-        getCalleeExpressionIfAny()
-            ?.safeAs<KtReferenceExpression>()
-            ?.resolve()
-            ?.safeAs<KtDeclaration>()
-            ?.let {
-                analysisAnalysisContext.declarationToTypeVariable[it]
-            } ?: KtPsiUtil.deparenthesize(this)?.let { analysisAnalysisContext.declarationToTypeVariable[it] }
-
-    private fun KtExpression.toBoundTypeAsTypeVariable(): BoundType? {
-        val typeVariableBoundType = resolveToTypeVariable()?.let {
-            TypeVariableBoundType(it, null)
-        } ?: return null
-        val asReferenceToVarArgParameter =
-            safeAs<KtNameReferenceExpression>()
-                ?.mainReference
-                ?.resolve()
-                ?.safeAs<KtParameter>()
-                ?.takeIf { it.isVarArg }
-        return if (asReferenceToVarArgParameter != null) {
-            GenericBoundType(
-                UnknownClassReference("Array"),//TODO
-                listOf(BoundTypeTypeParameter(typeVariableBoundType, Variance.INVARIANT)),
-                isNull = false
-            )
-        } else typeVariableBoundType
-    }
-
-    private fun KtExpression.toBoundTypeAsCallExpression(contextBoundType: BoundType?): BoundType? {
-        val typeElement = getCalleeExpressionIfAny()
-            ?.safeAs<KtReferenceExpression>()
-            ?.resolve()
-            ?.safeAs<KtCallableDeclaration>()
-            ?.typeReference
-            ?.typeElement
-        typeElement?.let { analysisAnalysisContext.typeElementToTypeVariable[it] }?.also {
-            return TypeVariableBoundType(it)
-        }
-        val bindingContext = analyze()
-        val descriptor =
-            getResolvedCall(bindingContext)?.candidateDescriptor?.original?.safeAs<CallableDescriptor>() ?: return null
-        val typeParameters =
-            run {
-                if (this is KtCallElement) {
-                    typeArguments.mapIndexed { index, typeArgument ->
-                        //TODO better check
-                        val typeParameter = descriptor.typeParameters.getOrNull(index) ?: return@run null
-                        val typeVariable =
-                            analysisAnalysisContext.typeElementToTypeVariable[typeArgument.typeReference?.typeElement ?: return@run null]
-                                ?: return@run null
-                        typeParameter to typeVariable
-                    }.toMap()
-                } else emptyMap()
-            } ?: emptyMap()
-        return descriptor.returnType?.toBoundType(contextBoundType, typeParameters)
-    }
-
-    private fun KtExpression.toBoundTypeAsCastExpression(): BoundType? {
-        val castExpression = KtPsiUtil.deparenthesize(this)
-            ?.safeAs<KtBinaryExpressionWithTypeRHS>()
-            ?.takeIf { KtPsiUtil.isUnsafeCast(it) }
-            ?: return null
-        return castExpression.right?.typeElement
-            ?.let { analysisAnalysisContext.typeElementToTypeVariable[it] }
-            ?.let { TypeVariableBoundType(it) }
-    }
-
-    private fun KtExpression.toBoundType(contextBoundType: BoundType?): BoundType? =
-        toBoundTypeAsTypeVariable()
-            ?: toBoundTypeAsCallExpression(contextBoundType)
-            ?: toBoundTypeAsCastExpression()
-
-    private fun KotlinType.toBoundType(
-        contextBoundType: BoundType?,
-        typeParameterDescriptors: Map<TypeParameterDescriptor, TypeVariable>
-    ): BoundType? {
-        fun KotlinType.toBoundType(): BoundType? {
-            val forcedNullability = when {
-                isMarkedNullable -> Nullability.NULLABLE
-                else -> null
-            }
-            val target = constructor.declarationDescriptor
-            return when (target) {
-                is ClassDescriptor -> {
-                    val classReference = DescriptorClassReference(target)
-                    GenericBoundType(
-                        classReference,
-                        (arguments zip constructor.parameters).map { (typeArgument, typeParameter) ->
-                            BoundTypeTypeParameter(
-                                typeArgument.type.toBoundType() ?: return null,
-                                typeParameter.variance
-                            )
-                        },
-                        forcedNullability,
-                        isNullable()
-                    )
-
-                }
-                is TypeParameterDescriptor -> {
-                    when {
-                        target in typeParameterDescriptors ->
-                            TypeVariableBoundType(typeParameterDescriptors.getValue(target), forcedNullability)
-                        contextBoundType != null ->
-                            contextBoundType.typeParameters.getOrNull(target.index)?.boundType?.withForcedNullability(forcedNullability)
-                        else -> null
-                    }
-                }
-                else -> error(toString())
-            }
-        }
-        return toBoundType()
-    }
-}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/ConstraintBuilder.kt

@@ -1,63 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import org.jetbrains.kotlin.psi.KtExpression
-import org.jetbrains.kotlin.types.Variance
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-internal class ConstraintBuilder(val boundTypeStorage: BoundTypeStorage) {
-    private val constraints = mutableListOf<Constraint>()
-
-    internal fun getConstraints(): List<Constraint> = constraints
-
-    fun KtExpression.addSubtypeNullabilityConstraint(typeVariable: TypeVariable, cameFrom: ConstraintCameFrom) {
-        addSubtypeNullabilityConstraint(TypeVariableBoundType(typeVariable), cameFrom)
-    }
-
-    fun KtExpression.addEqualsNullabilityConstraint(nullability: Nullability, cameFrom: ConstraintCameFrom) {
-        val boundType = boundTypeStorage.boundTypeFor(this).safeAs<TypeVariableBoundType>()
-            ?: return
-        constraints += EqualConstraint(boundType.bound, LiteralBound(nullability), cameFrom)
-    }
-
-    fun TypeVariable.addEqualsNullabilityConstraint(other: BoundType, cameFrom: ConstraintCameFrom) {
-        TypeVariableBoundType(this).isTheSameType(other, cameFrom)
-    }
-
-    fun KtExpression.addSubtypeNullabilityConstraint(upperTypeExpression: KtExpression, cameFrom: ConstraintCameFrom) {
-        boundTypeStorage.boundTypeFor(this).subtypeOf(boundTypeStorage.boundTypeFor(upperTypeExpression), cameFrom)
-    }
-
-    fun KtExpression.addSubtypeNullabilityConstraint(upperBoundType: BoundType, cameFrom: ConstraintCameFrom) {
-        boundTypeStorage.boundTypeFor(this)
-            .subtypeOf(upperBoundType, cameFrom)
-    }
-
-    fun TypeVariable.subtypeOf(other: BoundType, cameFrom: ConstraintCameFrom) {
-        TypeVariableBoundType(this).subtypeOf(other, cameFrom)
-    }
-
-    fun BoundType.subtypeOf(other: BoundType, cameFrom: ConstraintCameFrom) {
-        (typeParameters zip other.typeParameters).forEach { (left, right) ->
-            val variance = left.variance
-            when (variance) {
-                Variance.OUT_VARIANCE -> left.boundType.subtypeOf(right.boundType, cameFrom)
-                Variance.IN_VARIANCE -> right.boundType.subtypeOf(left.boundType, cameFrom)
-                Variance.INVARIANT -> right.boundType.isTheSameType(left.boundType, cameFrom)
-            }
-        }
-
-        constraints += SubtypeConstraint(bound, other.bound, cameFrom)
-    }
-
-    fun BoundType.isTheSameType(other: BoundType, cameFrom: ConstraintCameFrom) {
-        (typeParameters zip other.typeParameters).forEach { (left, right) ->
-            left.boundType.isTheSameType(right.boundType, cameFrom)
-        }
-        constraints += EqualConstraint(bound, other.bound, cameFrom)
-    }
-}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/constraints.kt

@@ -1,253 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.psi.PsiClass
-import com.intellij.psi.PsiTypeParameter
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.types.Variance
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-
-internal interface TypeVariableOwner {
-    val target: KtElement
-}
-
-internal interface SingleTypeVariableOwner : TypeVariableOwner {
-    val typeVariable: TypeVariable
-}
-
-internal interface MultipleTypeVariablesOwner : TypeVariableOwner {
-    val typeVariables: List<TypeVariable>
-}
-
-internal val TypeVariableOwner.allTypeVariables
-    get() = when (this) {
-        is SingleTypeVariableOwner -> listOf(typeVariable)
-        is MultipleTypeVariablesOwner -> typeVariables
-        else -> error("TypeVariableOwner should be either SingleTypeVariableOwner or MultipleTypeVariablesOwner")
-    }
-
-
-internal interface DeclarationTypeVariableOwner : SingleTypeVariableOwner {
-    override val target: KtCallableDeclaration
-}
-
-internal data class PropertyTarget(
-    override val target: KtProperty,
-    override val typeVariable: TypeVariable
-) : DeclarationTypeVariableOwner
-
-internal data class FunctionTarget(
-    override val target: KtNamedFunction,
-    override val typeVariable: TypeVariable
-) : DeclarationTypeVariableOwner
-
-internal data class LambdaTarget(
-    override val target: KtFunctionLiteral,
-    override val typeVariable: TypeVariable
-) : DeclarationTypeVariableOwner
-
-internal data class ParameterTarget(
-    override val target: KtParameter,
-    override val typeVariable: TypeVariable
-) : DeclarationTypeVariableOwner
-
-internal data class TypeCastTarget(
-    override val target: KtBinaryExpressionWithTypeRHS,
-    override val typeVariable: TypeVariable
-) : SingleTypeVariableOwner
-
-internal data class FunctionCallTypeArgumentTarget(
-    override val target: KtCallExpression,
-    override val typeVariables: List<TypeVariable>
-) : MultipleTypeVariablesOwner
-
-
-internal interface ClassReference
-internal data class KtClassReference(val klass: KtClassOrObject) : ClassReference
-internal data class DescriptorClassReference(val descriptor: ClassDescriptor) : ClassReference
-internal data class JavaClassReference(val klass: PsiClass) : ClassReference
-internal data class TypeParameterClassReference(val typeParameter: KtTypeParameter) : ClassReference
-internal data class UnknownClassReference(val text: String) : ClassReference
-internal object LiteralClassReference : ClassReference
-
-
-internal interface BoundType {
-    val classReference: ClassReference
-    val typeParameters: List<BoundTypeTypeParameter>
-    val forcedNullabilityTo: Nullability?
-}
-
-internal class TypeVariableBoundType(
-    val typeVariable: TypeVariable,
-    override val forcedNullabilityTo: Nullability? = null
-) : BoundType {
-    override val classReference: ClassReference = typeVariable.classReference
-    override val typeParameters: List<BoundTypeTypeParameter> =
-        typeVariable.typeParameters.map { typeParameter ->
-            val boundType =
-                if (typeParameter is TypeVariableTypeParameterWithTypeParameter)
-                    TypeVariableBoundType(typeParameter.typeVariable)
-                else StarProjectionBoundType
-
-            BoundTypeTypeParameter(
-                boundType,
-                typeParameter.variance //TODO isMarkedNullable
-            )
-        }
-}
-
-internal class GenericBoundType(
-    override val classReference: ClassReference,
-    override val typeParameters: List<BoundTypeTypeParameter>,
-    override val forcedNullabilityTo: Nullability? = null,
-    val isNull: Boolean
-) : BoundType
-
-internal class LiteralBoundType(val isNull: Boolean) : BoundType {
-    override val classReference = LiteralClassReference
-    override val typeParameters: List<BoundTypeTypeParameter> = emptyList()
-    override val forcedNullabilityTo: Nullability? = null
-}
-
-
-internal class TypeVariable(
-    val typeElement: KtTypeElement?,
-    val classReference: ClassReference,
-    val typeParameters: List<TypeVariableTypeParameter>,
-    var nullability: Nullability
-)
-
-internal inline val BoundType.bound
-    get() =
-        when {
-            forcedNullabilityTo != null -> LiteralBound(forcedNullabilityTo!!)
-            this is TypeVariableBoundType -> TypeVariableBound(typeVariable)
-            this is LiteralBoundType -> LiteralBound(isNull.nullableForTrue())
-            this is GenericBoundType -> LiteralBound(isNull.nullableForTrue())
-            this is StarProjectionBoundType -> LiteralBound(Nullability.NULLABLE)
-            else -> error("Bad bound type $this")
-        }
-
-internal inline fun <reified T : BoundType> T.withForcedNullability(nullability: Nullability?): T =
-    if (forcedNullabilityTo == nullability || nullability == null) this
-    else when (this) {
-        is GenericBoundType ->
-            GenericBoundType(
-                classReference,
-                typeParameters,
-                nullability,
-                isNull
-            )
-        is TypeVariableBoundType ->
-            TypeVariableBoundType(
-                typeVariable,
-                nullability
-            )
-        is LiteralBoundType -> this
-        else -> this
-    } as T
-
-internal interface TypeVariableTypeParameter {
-    val variance: Variance
-}
-
-internal data class TypeVariableTypeParameterWithTypeParameter(
-    val typeVariable: TypeVariable,
-    override val variance: Variance
-) : TypeVariableTypeParameter
-
-internal object TypeVariableStartProjectionTypeParameter : TypeVariableTypeParameter {
-    override val variance = Variance.INVARIANT //TODO ??
-}
-
-
-internal data class BoundTypeTypeParameter(
-    val boundType: BoundType,
-    val variance: Variance
-)
-
-internal object StarProjectionBoundType : BoundType {
-    override val classReference = UnknownClassReference("*")//TODO
-    override val typeParameters: List<BoundTypeTypeParameter> = emptyList()
-    override val forcedNullabilityTo = null
-}
-
-internal interface Constraint {
-    val cameFrom: ConstraintCameFrom
-}
-
-interface ConstraintBound
-
-internal data class TypeVariableBound(val typeVariable: TypeVariable) : ConstraintBound
-internal data class LiteralBound(val nullability: Nullability) : ConstraintBound
-
-internal data class SubtypeConstraint(
-    var lowerBound: ConstraintBound,
-    var upperBound: ConstraintBound,
-    override val cameFrom: ConstraintCameFrom
-) : Constraint
-
-enum class ConstraintCameFrom {
-    SUPER_DECLARATION,
-    INITIALIZER,
-    COMPARED_WITH_NULL,
-    ASSIGNMENT_TARGET,
-    USED_AS_RECEIVER,
-    PARAMETER_PASSED
-}
-
-internal data class EqualConstraint(
-    val leftBound: ConstraintBound,
-    val rightBound: ConstraintBound,
-    override val cameFrom: ConstraintCameFrom
-) : Constraint
-
-
-private fun PsiTypeParameter.variance() = Variance.INVARIANT//TODO real variance
-
-internal fun ClassReference.typeParametersVariance(parameterIndex: Int): Variance =
-    when (this) {
-        is KtClassReference -> klass.typeParameters.getOrNull(parameterIndex)?.variance ?: Variance.INVARIANT
-        is JavaClassReference -> klass.typeParameters.getOrNull(parameterIndex)?.variance() ?: Variance.INVARIANT
-        is DescriptorClassReference -> descriptor.typeConstructor.parameters[parameterIndex].variance
-        is TypeParameterClassReference -> Variance.INVARIANT
-        is UnknownClassReference -> Variance.INVARIANT
-        else -> error("Bad class reference `$this`")
-    }
-
-internal fun TypeVariable.setNullabilityIfNotFixed(nullability: Nullability) {
-    if (!isFixed) {
-        this.nullability = nullability
-    }
-}
-
-internal val TypeVariable.isFixed: Boolean
-    get() = nullability != Nullability.UNKNOWN
-
-enum class Nullability {
-    NULLABLE, NOT_NULL, UNKNOWN
-}
-
-internal fun Boolean.nullableForTrue() =
-    if (this) Nullability.NULLABLE else Nullability.NOT_NULL
-
-
-internal fun TypeVariableOwner.innerTypeVariables(): List<TypeVariable> =
-    when (this) {
-        is SingleTypeVariableOwner -> typeVariable.innerTypeVariables()
-        is MultipleTypeVariablesOwner -> typeVariables.flatMap { it.innerTypeVariables() }
-        else -> error("")
-    }
-
-internal fun TypeVariable.innerTypeVariables(): List<TypeVariable> =
-    typeParameters.flatMap { typeParameter ->
-        typeParameter.safeAs<TypeVariableTypeParameterWithTypeParameter>()?.let { typeVariableTypeParameter ->
-            typeVariableTypeParameter.typeVariable.innerTypeVariables() + listOfNotNull(typeVariableTypeParameter.typeVariable)
-        }.orEmpty()
-    }

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/constraintsCollector.kt

@@ -1,310 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.descriptors.CallableDescriptor
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.descriptors.FunctionDescriptor
-import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
-import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
-import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isNullExpression
-import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
-import org.jetbrains.kotlin.nj2k.*
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.asAssignment
-import org.jetbrains.kotlin.psi.psiUtil.forEachDescendantOfType
-import org.jetbrains.kotlin.resolve.bindingContextUtil.getTargetFunction
-import org.jetbrains.kotlin.resolve.calls.callUtil.getType
-import org.jetbrains.kotlin.resolve.calls.components.isVararg
-import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
-import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
-import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-
-internal class LabelToFunctionTypeVariableMapper(analysisContext: AnalysisContext) {
-    private val labelToFunction = analysisContext.declarationToTypeVariable.mapNotNull { (declaration, _) ->
-        if (declaration !is KtNamedFunction) return@mapNotNull null
-        val label = declaration.nameIdentifier?.getLabel() ?: return@mapNotNull null
-        label to declaration
-    }.toMap()
-
-    fun functionByLabel(label: JKElementInfoLabel): KtNamedFunction? =
-        labelToFunction[label]
-
-}
-
-internal class ConstraintsCollector(
-    private val analysisContext: AnalysisContext,
-    private val converterContext: NewJ2kConverterContext?,
-    printConstraints: Boolean
-) {
-    private val boundTypeStorage = BoundTypeStorage(analysisContext, printConstraints)
-    private val constraintBuilder = ConstraintBuilder(boundTypeStorage)
-    private val labelToFunctionTypeVariableMapper = LabelToFunctionTypeVariableMapper(analysisContext)
-
-    private val PsiElement.elementInfo: List<JKElementInfo>?
-        get() = getLabel()?.let { label ->
-            converterContext?.elementsInfoStorage?.getInfoForLabel(label)
-        }
-
-    private inline val KtExpression.boundType
-        get() = boundTypeStorage.boundTypeFor(this)
-
-
-    internal fun collectConstraints(analysisScope: AnalysisScope): List<Constraint> {
-        analysisScope.forEach { element ->
-            element.forEachDescendantOfType<KtExpression> { expression ->
-                collectConstraintsForExpression(expression)
-            }
-        }
-        return constraintBuilder.getConstraints()
-    }
-
-    private fun collectConstraintsForExpression(expression: KtExpression) = with(constraintBuilder) {
-        when {
-            expression is KtQualifiedExpression -> {
-                expression.receiverExpression.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.USED_AS_RECEIVER)
-            }
-
-            expression is KtBinaryExpressionWithTypeRHS && KtPsiUtil.isUnsafeCast(expression) -> {
-                expression.right?.typeElement?.let { analysisContext.typeElementToTypeVariable[it] }?.also { typeVariable ->
-                    expression.left.addSubtypeNullabilityConstraint(typeVariable, ConstraintCameFrom.ASSIGNMENT_TARGET)
-                }
-            }
-
-            expression is KtBinaryExpression && expression.asAssignment() != null -> {
-                expression.right?.addSubtypeNullabilityConstraint(expression.left ?: return, ConstraintCameFrom.ASSIGNMENT_TARGET)
-            }
-
-            expression is KtBinaryExpression && expression.isComaprationWithNull() -> {
-                val comparedExpression =
-                    if (expression.left.isNullExpression()) expression.right
-                    else expression.left
-                comparedExpression?.addEqualsNullabilityConstraint(Nullability.NULLABLE, ConstraintCameFrom.COMPARED_WITH_NULL)
-            }
-
-            expression is KtBinaryExpression -> {
-                expression.left?.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.USED_AS_RECEIVER)
-                expression.right?.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.USED_AS_RECEIVER)
-            }
-
-            expression is KtProperty -> {
-                analysisContext.declarationToTypeVariable[expression]?.also { typeVariable ->
-                    expression.initializer?.addSubtypeNullabilityConstraint(
-                        typeVariable,
-                        ConstraintCameFrom.INITIALIZER
-                    )
-                }
-            }
-
-            expression is KtParameter -> {
-                analysisContext.declarationToTypeVariable[expression]?.also { typeVariable ->
-                    expression.defaultValue?.addSubtypeNullabilityConstraint(
-                        typeVariable,
-                        ConstraintCameFrom.INITIALIZER
-                    )
-                }
-            }
-
-            expression is KtIfExpression -> {
-                expression.condition?.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.INITIALIZER)
-            }
-
-            expression is KtWhileExpression -> {
-                expression.condition?.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.INITIALIZER)
-            }
-
-            expression is KtCallExpression -> {
-                collectConstraintsForCallExpression(
-                    expression,
-                    expression.parent?.safeAs<KtQualifiedExpression>()?.receiverExpression
-                )
-            }
-
-            expression is KtReturnExpression -> {
-                val targetTypeVariable = expression.getTargetFunction(expression.analyze())?.let { function ->
-                    analysisContext.declarationToTypeVariable[function]
-                }
-                if (targetTypeVariable != null) {
-                    expression.returnedExpression?.addSubtypeNullabilityConstraint(
-                        targetTypeVariable,
-                        ConstraintCameFrom.ASSIGNMENT_TARGET
-                    )
-                }
-            }
-
-            expression is KtNamedFunction -> {
-                collectSuperDeclarationConstraintsForFunction(expression)
-            }
-
-            expression is KtForExpression -> {
-                expression.loopRange?.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.INITIALIZER)
-
-                val loopParameterTypeVariable =
-                    expression.loopParameter?.typeReference?.typeElement?.let { typeElement ->
-                        analysisContext.typeElementToTypeVariable[typeElement]
-                    }
-                if (loopParameterTypeVariable != null) {
-                    val loopRangeBoundType = boundTypeStorage.boundTypeFor(expression.loopRange ?: return)
-                    val loopRangeType = expression.loopRange?.getType(expression.analyze()) ?: return
-                    val loopRangeItemType = loopRangeType
-                        .constructor
-                        .declarationDescriptor
-                        ?.safeAs<ClassDescriptor>()
-                        ?.getMemberScope(loopRangeType.arguments)
-                        ?.getDescriptorsFiltered(DescriptorKindFilter.FUNCTIONS) {
-                            it.asString() == "iterator"
-                        }?.filterIsInstance<FunctionDescriptor>()
-                        ?.firstOrNull { it.valueParameters.isEmpty() }
-                        ?.original
-                        ?.returnType
-                        ?: return
-                    val boundType = boundTypeStorage.boundTypeForType(
-                        loopRangeItemType,
-                        loopRangeBoundType,
-                        emptyMap()
-                    ) ?: return
-                    loopParameterTypeVariable.addEqualsNullabilityConstraint(
-                        boundType.typeParameters.firstOrNull()?.boundType ?: return,
-                        ConstraintCameFrom.ASSIGNMENT_TARGET
-                    )
-                }
-            }
-        }
-        Unit
-    }
-
-
-    private fun SuperFunctionInfo.superFunctionBoundType(
-        originalFunctionDescriptor: FunctionDescriptor
-    ): BoundType? =
-        when (this) {
-            is ExternalSuperFunctionInfo -> {
-                val containingSuperClassBoundType =
-                    descriptor.containingDeclaration.safeAs<ClassDescriptor>()?.let { klass ->
-                        GenericBoundType(
-                            DescriptorClassReference(klass),
-                            emptyList(),//TODO,
-                            isNull = false
-                        )
-                    }
-                originalFunctionDescriptor.returnType?.let { type ->
-                    boundTypeStorage.boundTypeForType(type, containingSuperClassBoundType, emptyMap()/*TODO*/)
-                }
-            }
-            is InternalSuperFunctionInfo -> {
-                labelToFunctionTypeVariableMapper.functionByLabel(label)?.let { function ->
-                    analysisContext.declarationToTypeVariable[function]?.let { TypeVariableBoundType(it) }
-                }
-            }
-        }
-
-    private fun SuperFunctionInfo.superFunctionParameterBoundType(parameterIndex: Int): BoundType? {
-        return when (this) {
-            is ExternalSuperFunctionInfo -> {
-                val containingSuperClassBoundType =
-                    descriptor.containingDeclaration.safeAs<ClassDescriptor>()?.let { klass ->
-                        GenericBoundType(
-                            DescriptorClassReference(klass),
-                            emptyList(),//TODO,
-                            isNull = false
-                        )
-                    }
-                val parameter = descriptor.valueParameters.getOrNull(parameterIndex) ?: return null
-                boundTypeStorage.boundTypeForType(parameter.type, containingSuperClassBoundType, emptyMap()/*TODO*/)
-            }
-            is InternalSuperFunctionInfo -> {
-                val function = labelToFunctionTypeVariableMapper.functionByLabel(label) ?: return null
-                val parameter = function.valueParameters.getOrNull(parameterIndex) ?: return null
-                analysisContext.declarationToTypeVariable[parameter]?.let { TypeVariableBoundType(it) }
-            }
-        }
-    }
-
-
-    private fun collectSuperDeclarationConstraintsForFunction(function: KtNamedFunction) = with(constraintBuilder) {
-        val (descriptor, superDeclarationDescriptors) =
-            function.nameIdentifier?.elementInfo?.firstIsInstanceOrNull<FunctionInfo>() ?: return@with
-
-        for (superDeclarationInfo in superDeclarationDescriptors) {
-            val superFunctionBoundType = superDeclarationInfo.superFunctionBoundType(descriptor) ?: continue
-
-            analysisContext.declarationToTypeVariable[function]?.addEqualsNullabilityConstraint(
-                superFunctionBoundType,
-                ConstraintCameFrom.SUPER_DECLARATION
-            )
-
-            for (parameterIndex in function.valueParameters.indices) {
-                val parameterTypeVariable =
-                    function.valueParameters[parameterIndex].let { analysisContext.declarationToTypeVariable[it] } ?: return
-                val superParameterBoundType = superDeclarationInfo.superFunctionParameterBoundType(parameterIndex) ?: return
-                parameterTypeVariable.addEqualsNullabilityConstraint(superParameterBoundType, ConstraintCameFrom.SUPER_DECLARATION)
-            }
-        }
-    }
-
-
-    private fun collectConstraintsForCallExpression(callExpression: KtCallExpression, receiver: KtExpression?) = with(constraintBuilder) {
-        val receiverBoundType = receiver?.boundType
-        val descriptor = callExpression.resolveToCall()?.candidateDescriptor?.original?.safeAs<CallableDescriptor>() ?: return
-        val function = descriptor.findPsi()?.safeAs<KtNamedFunction>()
-
-        fun parameterBoundTypeIndex(index: Int): BoundType? =
-            function?.valueParameters?.let { parameters ->
-                val parameter =
-                    if (index <= parameters.lastIndex) parameters[index]
-                    else parameters.lastOrNull()?.takeIf { parameter ->
-                        parameter.isVarArg
-                    }
-                val typeVariable = parameter?.let { analysisContext.declarationToTypeVariable[it] }
-                typeVariable?.let {
-                    TypeVariableBoundType(it)
-                }
-            } ?: run {
-                if (index < descriptor.valueParameters.lastIndex
-                    || index == descriptor.valueParameters.lastIndex && descriptor.valueParameters.lastOrNull()?.isVararg == false
-                ) descriptor.valueParameters[index].type
-                else {
-                    descriptor.valueParameters.lastOrNull()?.takeIf { parameter ->
-                        parameter.isVararg && KotlinBuiltIns.isArray(parameter.type)
-                    }?.let { parameter ->
-                        parameter.type.arguments.singleOrNull()?.type
-                    }
-                }
-            }?.let { type ->
-                boundTypeStorage
-                    .boundTypeForType(type, receiverBoundType, callExpression.typeArgumentsDescriptors(descriptor).orEmpty())
-            }
-
-
-        for (argumentIndex in callExpression.valueArguments.indices) {
-            val valueArgument = callExpression.valueArguments[argumentIndex]
-            val argument = valueArgument.getArgumentExpression() ?: continue
-
-            if (valueArgument.isSpread) {
-                argument.addEqualsNullabilityConstraint(Nullability.NOT_NULL, ConstraintCameFrom.USED_AS_RECEIVER)
-            }
-
-            argument.addSubtypeNullabilityConstraint(
-                parameterBoundTypeIndex(argumentIndex) ?: continue,
-                ConstraintCameFrom.PARAMETER_PASSED
-            )
-        }
-    }
-
-    private fun KtCallExpression.typeArgumentsDescriptors(descriptor: CallableDescriptor): Map<TypeParameterDescriptor, TypeVariable>? {
-        return descriptor.typeParameters.zip(typeArguments) { typeParameter, typeArgument ->
-            val typeVariable =
-                analysisContext.typeElementToTypeVariable[typeArgument.typeReference?.typeElement ?: return null]
-                    ?: return null
-            typeParameter to typeVariable
-        }.toMap()
-    }
-}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/context.kt

@@ -1,159 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.openapi.editor.RangeMarker
-import com.intellij.openapi.util.TextRange
-import com.intellij.psi.PsiComment
-import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.nj2k.JKElementInfoLabel
-import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
-import org.jetbrains.kotlin.nj2k.asLabel
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
-import org.jetbrains.kotlin.psi.psiUtil.elementsInRange
-import org.jetbrains.kotlin.resolve.calls.callUtil.getType
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-internal class ContextCreator(private val getNullability: (KtTypeElement) -> Nullability) {
-
-    private fun KtCallableDeclaration.typeElement(): KtTypeElement? =
-        typeReference?.typeElement
-
-    private fun KtElement.asTypeVariableOwner(): TypeVariableOwner? {
-        return when (this) {
-            is KtParameter -> typeElement()?.asTypeVariable()?.let { ParameterTarget(this, it) }
-            is KtProperty -> typeElement()?.asTypeVariable()?.let { PropertyTarget(this, it) }
-            is KtNamedFunction -> typeElement()?.asTypeVariable()?.let { FunctionTarget(this, it) }
-            is KtLambdaExpression -> {
-                val context = analyze()
-                val returnType = getType(context)?.arguments?.lastOrNull()?.type ?: return null
-                val typeVariable = returnType.asTypeVariable() ?: return null
-                LambdaTarget(functionLiteral, typeVariable)
-            }
-
-            is KtBinaryExpressionWithTypeRHS -> right?.typeElement
-                ?.takeIf { KtPsiUtil.isUnsafeCast(this) }
-                ?.asTypeVariable()
-                ?.let { TypeCastTarget(this, it) }
-
-            is KtCallExpression ->
-                if (typeArguments.isNotEmpty())
-                    FunctionCallTypeArgumentTarget(
-                        this,
-                        typeArguments.map { it.typeReference?.typeElement?.asTypeVariable() ?: return null }
-                    )
-                else null
-            else -> null
-        }
-    }
-
-    fun createContext(analysisScope: AnalysisScope): AnalysisContext {
-        val typeVariableOwners = analysisScope.flatMap {
-            it.collectDescendantsOfType<KtElement>().mapNotNull { ktElement ->
-                ktElement.asTypeVariableOwner()
-            }
-        }
-
-        val typeElementsToTypeVariables =
-            typeVariableOwners.flatMap {
-                it.innerTypeVariables() + it.allTypeVariables
-            }.filter { it.typeElement != null }
-                .associateBy { it.typeElement!! }
-
-        val declarationToTypeVariable = typeVariableOwners.asSequence()
-            .mapNotNull { owner ->
-                if (owner is DeclarationTypeVariableOwner)
-                    owner.target to owner.typeVariable
-                else null
-            }.toMap()
-        return AnalysisContext(typeVariableOwners, typeElementsToTypeVariables, declarationToTypeVariable)
-    }
-
-    private fun KtTypeElement.asTypeVariable(): TypeVariable {
-        val nullability = getNullability(this)
-        val classReference: ClassReference = classReference()
-        val typeParameters: List<TypeVariableTypeParameter> =
-            typeArgumentsAsTypes.mapIndexed { index, typeRef ->
-                typeRef?.typeElement?.asTypeVariable()?.let { typeVariable ->
-                    TypeVariableTypeParameterWithTypeParameter(
-                        typeVariable,
-                        classReference.typeParametersVariance(index)
-                    )
-                } ?: TypeVariableStartProjectionTypeParameter
-
-            }
-        return TypeVariable(this, classReference, typeParameters, nullability)
-    }
-
-    private fun KotlinType.asTypeVariable(): TypeVariable? {
-        val classReference = constructor
-            .declarationDescriptor
-            ?.safeAs<ClassDescriptor>()
-            ?.let { DescriptorClassReference(it) }
-            ?: return null
-        val typeParameters =
-            arguments.zip(constructor.parameters) { argument, parameter ->
-                TypeVariableTypeParameterWithTypeParameter(
-                    argument.type.asTypeVariable() ?: return null,
-                    parameter.variance
-                )
-            }
-        return TypeVariable(null, classReference, typeParameters, Nullability.UNKNOWN)
-    }
-}
-
-
-fun nullabilityByUndefinedNullabilityComment(typeElement: KtTypeElement, context: NewJ2kConverterContext): Nullability {
-    val hasUndefinedNullabilityLabel =
-        typeElement.parent?.safeAs<KtTypeReference>()?.hasUndefinedNullabilityLabel(context) ?: false
-    return when {
-        hasUndefinedNullabilityLabel -> Nullability.UNKNOWN
-        typeElement is KtNullableType -> Nullability.NULLABLE
-        else -> Nullability.NOT_NULL
-    }
-}
-
-
-fun PsiElement.getLabel(): JKElementInfoLabel? =
-    prevSibling?.safeAs<PsiComment>()?.text?.asLabel()
-        ?: parent?.safeAs<KtTypeProjection>()?.getLabel()
-
-private fun KtTypeReference.hasUndefinedNullabilityLabel(context: NewJ2kConverterContext) =
-    getLabel()?.let { label ->
-        context.elementsInfoStorage.getInfoForLabel(label).orEmpty().contains(org.jetbrains.kotlin.nj2k.UnknownNullability)
-    } ?: false
-
-fun prepareTypeElementByMakingAllTypesNullableConsideringNullabilityComment(typeElement: KtTypeElement, context: NewJ2kConverterContext) {
-    val hasUndefinedNullabilityLabel =
-        typeElement.parent?.safeAs<KtTypeReference>()?.hasUndefinedNullabilityLabel(context) ?: false
-
-    if (hasUndefinedNullabilityLabel) {
-        typeElement.changeNullability(toNullable = true)
-    }
-}
-
-fun prepareTypeElementByMakingAllTypesNullable(typeElement: KtTypeElement) {
-    typeElement.changeNullability(toNullable = true)
-}
-
-
-internal data class AnalysisContext(
-    val typeVariableOwners: List<TypeVariableOwner>,
-    val typeElementToTypeVariable: Map<KtTypeElement, TypeVariable>,
-    val declarationToTypeVariable: Map<KtCallableDeclaration, TypeVariable>
-)
-
-data class AnalysisScope(val elements: List<PsiElement>) : Iterable<PsiElement> by elements {
-    constructor(vararg elements: KtElement) : this(elements.toList())
-    constructor(file: KtFile, rangeMarker: RangeMarker?) :
-            this(rangeMarker?.let { marker ->
-                file.elementsInRange(TextRange(marker.startOffset, marker.endOffset))
-            } ?: listOf(file))
-}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/nullabilityAnalysis.kt

@@ -1,133 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.openapi.application.runWriteAction
-import com.intellij.openapi.command.CommandProcessor
-import com.intellij.psi.PsiClass
-import com.intellij.psi.PsiComment
-import com.intellij.psi.PsiElement
-import com.intellij.psi.PsiElementVisitor
-import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
-import org.jetbrains.kotlin.nj2k.asLabel
-import org.jetbrains.kotlin.nj2k.parentOfType
-import org.jetbrains.kotlin.nj2k.postProcessing.resolve
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
-import org.jetbrains.kotlin.psi.psiUtil.isAncestor
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
-
-
-internal fun TypeVariable.changeNullability(toNullable: Boolean) {
-    typeElement?.changeNullability(toNullable)
-}
-
-internal fun KtTypeElement.changeNullability(toNullable: Boolean) {
-    val factory = KtPsiFactory(this)
-    if (this is KtNullableType && !toNullable) {
-        replace(factory.createType(innerType?.text ?: return).typeElement ?: return)
-    }
-    if (this !is KtNullableType && toNullable) {
-        replace(factory.createType("$text?").typeElement ?: return)
-    }
-}
-
-
-internal fun AnalysisContext.fixTypeVariablesNullability() {
-    if (typeElementToTypeVariable.isEmpty()) return
-
-    val deepComparator = Comparator<TypeVariable> { o1, o2 ->
-        if (o1.typeElement == null || o2.typeElement == null) return@Comparator -1
-        if (o1.typeElement.isAncestor(o2.typeElement)) 1 else -1
-    }
-    for (typeVariableOwner in typeVariableOwners) {
-        for (typeVariable in (typeVariableOwner.innerTypeVariables() + typeVariableOwner.allTypeVariables).sortedWith(deepComparator)) {
-            when (typeVariable.nullability) {
-                Nullability.NOT_NULL -> typeVariable.changeNullability(toNullable = false)
-                Nullability.NULLABLE -> typeVariable.changeNullability(toNullable = true)
-                Nullability.UNKNOWN -> {
-                    if (typeVariableOwner is FunctionCallTypeArgumentTarget) {
-                        typeVariable.changeNullability(toNullable = false)
-                    } else {
-                        typeVariable.changeNullability(toNullable = true)
-                    }
-                }
-            }
-        }
-    }
-}
-
-internal fun KtTypeElement.classReference(): ClassReference {
-    val target = when (this) {
-        is KtNullableType -> innerType?.safeAs()
-        is KtUserType -> this
-        else -> null
-    }?.referenceExpression?.resolve()
-    return when (target) {
-        is KtClassOrObject -> KtClassReference(target)
-        is PsiClass -> JavaClassReference(target)
-        is KtTypeAlias -> target.getTypeReference()?.typeElement?.classReference()
-        is KtTypeParameter -> TypeParameterClassReference(target)
-        else -> null
-    } ?: UnknownClassReference(text)
-}
-
-class NullabilityAnalysisFacade(
-    private val conversionContext: NewJ2kConverterContext?,
-    private val getTypeElementNullability: (KtTypeElement) -> Nullability,
-    private val prepareTypeElement: (KtTypeElement) -> Unit,
-    private val debugPrint: Boolean
-) {
-    fun fixNullability(analysisScope: AnalysisScope) {
-        CommandProcessor.getInstance().runUndoTransparentAction {
-            runWriteAction {
-                analysisScope.prepareTypeElements(prepareTypeElement)
-                val context = ContextCreator(getTypeElementNullability).createContext(analysisScope)
-                if (debugPrint) {
-                    with(Printer(context)) {
-                        analysisScope.forEach { it.addTypeVariablesNames() }
-                    }
-                }
-
-                val constraints = ConstraintsCollector(context, conversionContext, debugPrint).collectConstraints(analysisScope)
-                Solver(context, debugPrint).solveConstraints(constraints)
-                context.fixTypeVariablesNullability()
-                analysisScope.clearUndefinedLabels()
-            }
-        }
-    }
-}
-
-private fun AnalysisScope.prepareTypeElements(prepareTypeElement: (KtTypeElement) -> Unit) {
-    val typeElements = flatMap { it.collectDescendantsOfType<KtTypeReference>() }
-    typeElements.forEach { typeReference ->
-        val typeElement = typeReference.typeElement ?: return@forEach
-        if (typeElement.parentOfType<KtSuperTypeCallEntry>() == null) {
-            prepareTypeElement(typeElement)
-        }
-    }
-}
-
-
-private fun AnalysisScope.clearUndefinedLabels() {
-    val comments = mutableListOf<PsiComment>()
-    forEach { element ->
-        element.accept(object : PsiElementVisitor() {
-            override fun visitElement(element: PsiElement) {
-                element.acceptChildren(this)
-            }
-
-            override fun visitComment(comment: PsiComment) {
-                if (comment.text.asLabel() != null) {
-                    comments += comment
-                }
-            }
-        })
-    }
-    comments.forEach { it.delete() }
-}
-
-

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/printing.kt

@@ -1,85 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.psi.KtPsiFactory
-import org.jetbrains.kotlin.psi.KtTypeElement
-import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
-
-internal class Printer(private val analysisContext: AnalysisContext) {
-    private val namer = Namer(analysisContext)
-
-    internal val TypeVariable.name: String
-        get() = namer.name(this)
-
-    private fun ClassReference.asString() =
-        when (this) {
-            is KtClassReference -> klass.name
-            is JavaClassReference -> klass.name
-            is DescriptorClassReference -> descriptor.name.toString()
-            is TypeParameterClassReference -> typeParameter.name
-            is LiteralClassReference -> "LITERAL"
-            is UnknownClassReference -> text
-            else -> error(this::class.toString())
-        }
-
-    fun BoundType.asString(): String =
-        buildString {
-            if (this@asString is TypeVariableBoundType) {
-                append(this@asString.typeVariable.name)
-                append("@")
-            }
-            append(classReference.asString())
-            if (typeParameters.isNotEmpty()) {
-                typeParameters.joinTo(this, ", ", "<", ">") { it.boundType.asString() }
-            }
-        }
-
-    private fun Constraint.asString() =
-        when (this) {
-            is EqualConstraint -> "${leftBound.asString()} := ${rightBound.asString()}"
-            is SubtypeConstraint -> "${lowerBound.asString()} <: ${upperBound.asString()}"
-            else -> error("Unknown constraint ${this::class.qualifiedName}")
-        } + ", because of '$cameFrom'"
-
-
-    private fun ConstraintBound.asString(): String =
-        when (this) {
-            is LiteralBound -> nullability.toString()
-            is TypeVariableBound -> typeVariable.name
-            else -> error("Unknown constraint bound ${this::class.qualifiedName}")
-        }
-
-
-    internal fun PsiElement.addTypeVariablesNames() {
-        val factory = KtPsiFactory(this)
-        for (typeElement in collectDescendantsOfType<KtTypeElement>()) {
-            val typeVariableName = this@Printer.analysisContext.typeElementToTypeVariable[typeElement]?.name ?: continue
-            val comment = factory.createComment("/*$typeVariableName@*/")
-            typeElement.parent.addBefore(comment, typeElement)
-        }
-    }
-
-    internal fun List<Constraint>.listConstrains() =
-        joinToString(separator = "\n") { it.asString() }
-}
-
-
-private class Namer(analysisContext: AnalysisContext) {
-    val names = run {
-        val typeVariables =
-            analysisContext.typeVariableOwners.flatMap { owner ->
-                owner.allTypeVariables.flatMap { it.innerTypeVariables() + it }
-            }
-        typeVariables.mapIndexed { index, typeVariable ->
-            typeVariable to "T$index"
-        }.toMap()
-    }
-
-    fun name(typeVariable: TypeVariable): String =
-        names.getValue(typeVariable)
-}

nj2k/nj2k-services/src/org/jetbrains/kotlin/nj2k/nullabilityAnalysis/utils.kt

@@ -1,73 +0,0 @@
-/*
- * 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.nullabilityAnalysis
-
-import com.intellij.psi.tree.IElementType
-import org.jetbrains.kotlin.config.LanguageVersionSettingsImpl
-import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
-import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isNullExpression
-import org.jetbrains.kotlin.lexer.KtTokens
-import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.resolve.calls.callUtil.getType
-import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
-import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValue
-import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactoryImpl
-import org.jetbrains.kotlin.resolve.jvm.checkers.mustNotBeNull
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.types.isNullable
-import org.jetbrains.kotlin.util.javaslang.getOrNull
-
-internal fun KtExpression.deepestReceiver(): KtExpression =
-    generateSequence(this) {
-        if (it is KtQualifiedExpression) it.receiverExpression else null
-    }.last()
-
-internal fun KtExpression.isNullable(): Boolean =
-    getType(analyze())?.isNullable() != false
-
-internal fun KtExpression.getForcedNullability(): Nullability? {
-    val bindingContext = analyze()
-    val type = this.getType(bindingContext) ?: return null
-    if (!type.isNullable()) return Nullability.NOT_NULL
-
-    //TODO better way of getting DataFlowValueFactoryImpl
-    val dataFlowValue = DataFlowValueFactoryImpl(LanguageVersionSettingsImpl.DEFAULT)
-        .createDataFlowValue(
-            this,
-            type,
-            bindingContext,
-            getResolutionFacade().moduleDescriptor
-        )
-    val dataFlowInfo = analyze()[BindingContext.EXPRESSION_TYPE_INFO, this]?.dataFlowInfo ?: return null
-    return when {
-        dataFlowInfo.completeNullabilityInfo.get(dataFlowValue)?.getOrNull() ==
-                org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability.NOT_NULL -> Nullability.NOT_NULL
-        type.isExternallyAnnotatedNotNull(dataFlowInfo, dataFlowValue) -> Nullability.NOT_NULL
-        else -> null
-    }
-}
-
-
-private fun KotlinType.isExternallyAnnotatedNotNull(dataFlowInfo: DataFlowInfo, dataFlowValue: DataFlowValue): Boolean =
-    mustNotBeNull()?.isFromJava == true && dataFlowInfo.getStableNullability(dataFlowValue).canBeNull()
-
-private fun IElementType.isEqualsToken() =
-    this == KtTokens.EQEQ
-            || this == KtTokens.EXCLEQ
-            || this == KtTokens.EQEQEQ
-            || this == KtTokens.EXCLEQEQEQ
-
-fun KtBinaryExpression.isComaprationWithNull() =
-    operationToken.isEqualsToken() &&
-            (left.isNullExpression() || right.isNullExpression())
-
-fun KtExpression.isLiteral() =
-    this is KtStringTemplateExpression
-            || this is KtLiteralStringTemplateEntry
-            || this is KtConstantExpression
-            || isNullExpression()

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

@@ -161,6 +161,7 @@ private val removeRedundantElementsProcessingGroup =
         runSingleTime = true,
         processings = listOf(
             RemoveExplicitTypeArgumentsProcessing(),
+            RemoveJavaStreamsCollectCallTypeArgumentsProcessing(),
             generalInspectionBasedProcessing(RedundantCompanionReferenceInspection()),
             generalInspectionBasedProcessing(ExplicitThisInspection()),
             intentionBasedProcessing(RemoveEmptyClassBodyIntention())
@@ -234,7 +235,10 @@ private val cleaningUpDiagnosticBasedPostProcessingGroup =
 private val processings: List<NamedPostProcessingGroup> = listOf(
     NamedPostProcessingGroup(
         "Inferring declarations nullability",
-        listOf(nullabilityProcessing)
+        listOf(
+            nullabilityProcessing,
+            clearUndefinedLabelsProcessing
+        )
     ),
     NamedPostProcessingGroup(
         "Formatting code",

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

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.nj2k.postProcessing.processings
 
 import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiMethod
 import com.intellij.psi.search.searches.ReferencesSearch
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
@@ -41,7 +42,6 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.types.isNullable
-import org.jetbrains.kotlin.types.typeUtil.makeNotNullable
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
@@ -57,8 +57,7 @@ class RemoveExplicitPropertyTypeProcessing : ApplicabilityBasedInspectionLikePro
         val withoutExpectedType =
             initializer.analyzeInContext(initializer.getResolutionScope()).getType(initializer) ?: return false
         val descriptor = element.resolveToDescriptorIfAny() as? CallableDescriptor ?: return false
-        return if (element.isVar) withoutExpectedType == descriptor.returnType
-        else withoutExpectedType.makeNotNullable() == descriptor.returnType?.makeNotNullable()
+        return withoutExpectedType == descriptor.returnType
     }
 
     override fun apply(element: KtProperty) {
@@ -101,6 +100,26 @@ class RemoveExplicitTypeArgumentsProcessing : ApplicabilityBasedInspectionLikePr
     }
 }
 
+// the types arguments for Stream.collect calls cannot be explicitly specified in Kotlin
+// but we need them in nullability inference, so we remove it here
+class RemoveJavaStreamsCollectCallTypeArgumentsProcessing :
+    ApplicabilityBasedInspectionLikeProcessing<KtCallExpression>(KtCallExpression::class) {
+    override fun isApplicableTo(element: KtCallExpression, settings: ConverterSettings?): Boolean {
+        if (element.typeArgumentList == null) return false
+        val resolved = element.calleeExpression?.mainReference?.resolve() as? PsiMethod ?: return false
+        return resolved.getKotlinFqName()?.asString() == COLLECT_FQ_NAME
+    }
+
+    override fun apply(element: KtCallExpression) {
+        element.typeArgumentList?.delete()
+    }
+
+    companion object {
+        private const val COLLECT_FQ_NAME = "java.util.stream.Stream.collect"
+    }
+}
+
+
 class RemoveRedundantOverrideVisibilityProcessing : InspectionLikeProcessing {
     override val writeActionNeeded = true
 

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

@@ -6,23 +6,33 @@
 package org.jetbrains.kotlin.nj2k.postProcessing.processings
 
 import com.intellij.codeInsight.actions.OptimizeImportsProcessor
+import com.intellij.psi.PsiComment
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.codeStyle.CodeStyleManager
+import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.core.ShortenReferences
 import org.jetbrains.kotlin.idea.core.util.range
 import org.jetbrains.kotlin.idea.formatter.commitAndUnblockDocument
-import org.jetbrains.kotlin.nj2k.nullabilityAnalysis.AnalysisScope
-import org.jetbrains.kotlin.nj2k.nullabilityAnalysis.NullabilityAnalysisFacade
-import org.jetbrains.kotlin.nj2k.nullabilityAnalysis.nullabilityByUndefinedNullabilityComment
-import org.jetbrains.kotlin.nj2k.nullabilityAnalysis.prepareTypeElementByMakingAllTypesNullableConsideringNullabilityComment
+import org.jetbrains.kotlin.nj2k.asLabel
+import org.jetbrains.kotlin.nj2k.inference.common.BoundTypeCalculatorImpl
+import org.jetbrains.kotlin.nj2k.inference.common.ByInfoSuperFunctionsProvider
+import org.jetbrains.kotlin.nj2k.inference.common.ConstraintsCollectorAggregator
+import org.jetbrains.kotlin.nj2k.inference.common.InferenceFacade
+import org.jetbrains.kotlin.nj2k.inference.common.collectors.CallExpressionConstraintCollector
+import org.jetbrains.kotlin.nj2k.inference.common.collectors.CommonConstraintsCollector
+import org.jetbrains.kotlin.nj2k.inference.common.collectors.FunctionConstraintsCollector
+import org.jetbrains.kotlin.nj2k.inference.nullability.NullabilityBoundTypeEnhancer
+import org.jetbrains.kotlin.nj2k.inference.nullability.NullabilityConstraintsCollector
+import org.jetbrains.kotlin.nj2k.inference.nullability.NullabilityContextCollector
+import org.jetbrains.kotlin.nj2k.inference.nullability.NullabilityStateUpdater
 import org.jetbrains.kotlin.nj2k.postProcessing.postProcessing
-import org.jetbrains.kotlin.psi.KtElement
-import org.jetbrains.kotlin.psi.KtImportDirective
-import org.jetbrains.kotlin.psi.KtImportList
-import org.jetbrains.kotlin.psi.KtPackageDirective
+import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.elementsInRange
 
 val formatCodeProcessing =
     postProcessing { file, rangeMarker, _ ->
+        file.commitAndUnblockDocument()
         val codeStyleManager = CodeStyleManager.getInstance(file.project)
         if (rangeMarker != null) {
             if (rangeMarker.isValid) {
@@ -35,14 +45,49 @@ val formatCodeProcessing =
 
 val nullabilityProcessing =
     postProcessing { file, rangeMarker, converterContext ->
-        NullabilityAnalysisFacade(
-            converterContext,
-            getTypeElementNullability = { nullabilityByUndefinedNullabilityComment(it, converterContext) },
-            prepareTypeElement = { prepareTypeElementByMakingAllTypesNullableConsideringNullabilityComment(it, converterContext) },
-            debugPrint = false
-        ).fixNullability(AnalysisScope(file, rangeMarker))
+        val resolutionFacade = file.getResolutionFacade()
+        val inferenceFacade = InferenceFacade(
+            NullabilityContextCollector(resolutionFacade, converterContext),
+            ConstraintsCollectorAggregator(
+                resolutionFacade,
+                listOf(
+                    CommonConstraintsCollector(),
+                    CallExpressionConstraintCollector(),
+                    FunctionConstraintsCollector(ByInfoSuperFunctionsProvider(resolutionFacade, converterContext)),
+                    NullabilityConstraintsCollector()
+                )
+            ),
+            BoundTypeCalculatorImpl(resolutionFacade, NullabilityBoundTypeEnhancer(resolutionFacade)),
+            NullabilityStateUpdater()
+        )
+        val elements = if (rangeMarker != null) {
+            file.elementsInRange(rangeMarker.range ?: return@postProcessing).filterIsInstance<KtElement>()
+        } else listOf(file)
+
+        inferenceFacade.runOn(elements)
     }
 
+val clearUndefinedLabelsProcessing =
+    postProcessing { file, _, _ ->
+        file.clearUndefinedLabels()
+    }
+
+private fun KtFile.clearUndefinedLabels() {
+    val comments = mutableListOf<PsiComment>()
+    accept(object : PsiElementVisitor() {
+        override fun visitElement(element: PsiElement) {
+            element.acceptChildren(this)
+        }
+
+        override fun visitComment(comment: PsiComment) {
+            if (comment.text.asLabel() != null) {
+                comments += comment
+            }
+        }
+    })
+    comments.forEach { it.delete() }
+}
+
 val shortenReferencesProcessing =
     postProcessing { file, rangeMarker, _ ->
         if (rangeMarker != null) {

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

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * 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
@@ -725,7 +714,9 @@ class NewCodeBuilder(context: NewJ2kConverterContext) {
 
         override fun visitArrayAccessExpressionRaw(arrayAccessExpression: JKArrayAccessExpression) {
             arrayAccessExpression.expression.accept(this)
-            printer.par(ParenthesisKind.SQUARE) { arrayAccessExpression.indexExpression.accept(this) }
+            printer.print(".get(")
+            arrayAccessExpression.indexExpression.accept(this)
+            printer.print(")")
         }
 
         override fun visitPackageAccessExpressionRaw(packageAccessExpression: JKPackageAccessExpression) {
@@ -946,9 +937,7 @@ private class JKPrinter(
 
     fun renderType(type: JKType, owner: JKTreeElement?) {
         if (type is JKNoTypeImpl) return
-        elementInfoStorage.getOrCreateInfoForElement(type).let {
-            print(it.render())
-        }
+        print(elementInfoStorage.getOrCreateInfoForElement(type).render())
         when (type) {
             is JKClassType -> {
                 renderClassSymbol(type.classReference, owner)
@@ -975,6 +964,12 @@ private class JKPrinter(
         if (type.nullability == Nullability.Nullable) {
             printWithNoIndent("?")
         }
+        // we print undefined types as nullable because we need smartcast work in nullability inference in post-processing
+        if (type.nullability == Nullability.Default
+            && owner?.safeAs<JKLambdaExpression>()?.functionalType?.type != type
+        ) {
+            printWithNoIndent("?")
+        }
     }
 
     fun renderClassSymbol(classSymbol: JKClassSymbol, owner: JKTreeElement?) {

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

@@ -36,14 +36,14 @@ class AddElementsInfoConversion(private val context: NewJ2kConverterContext) : R
         val psiMethod = function.psi<PsiMethod>() ?: return
         val descriptor = psiMethod.getJavaMethodDescriptor() ?: return
         val superDescriptorsInfo =
-            descriptor.overriddenDescriptors.map { superDescriptor ->
-                val psi = superDescriptor.findPsi() ?: return@map ExternalSuperFunctionInfo(descriptor)
-                when (val symbol = context.symbolProvider.symbolsByPsi[psi]) {
+            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(descriptor)
+                    else -> ExternalSuperFunctionInfo(superDescriptor)
                 }
             }
         context.elementsInfoStorage.addEntry(function, FunctionInfo(descriptor, superDescriptorsInfo))

nj2k/testData/copyPaste/SeveralMethodsSample.expected.kt

@@ -1,7 +1,7 @@
 class A {
     fun someOther() = false
 
-    private fun formatElement(element: PsiElement): String {
+    private fun formatElement(element: PsiElement): String? {
         var element: PsiElement = element
         element = JetPsiUtil.ascendIfPropertyAccessor(element)
         if (element is JetNamedFunction || element is JetProperty) {
@@ -28,9 +28,9 @@ class A {
     }
 
     fun getSelected(): ArrayList<UsageInfo> {
-        val result: ArrayList<UsageInfo> = ArrayList<UsageInfo>()
+        val result: ArrayList<UsageInfo> = ArrayList<UsageInfo?>()
         for (i in 0 until myChecked.length) {
-            if (myChecked[i]) {
+            if (myChecked.get(i)) {
                 result.add(myOverridingMethods.get(i))
             }
         }

nj2k/testData/copyPastePlainText/AsExpression.expected.kt

@@ -3,5 +3,5 @@ import java.util.ArrayList
 
 
 fun foo() {
-    bar(ArrayList<String>())
+    bar(ArrayList<String?>())
 }

nj2k/testData/copyPastePlainText/AsExpressionBody.expected.kt

@@ -2,4 +2,4 @@
 import java.util.ArrayList
 
 
-fun foo() = ArrayList<String>()
+fun foo() = ArrayList<String?>()

nj2k/testData/copyPastePlainText/ImportFromTarget.expected.kt

@@ -4,7 +4,7 @@ import java.util.UUID
 
 
 class ExampleClass {
-    override fun toString(): String {
+    override fun toString(): String? {
         return UUID.randomUUID().toString()
     }
 }

nj2k/testData/copyPastePlainText/ImportResolve.expected.kt

@@ -9,7 +9,7 @@ import java.util.HashMap
 class Target {
     var listOfPlatformType: List<String> = ArrayList()
 
-    var unresolved: UnresolvedInterface<UnresolvedGeneric?>? = UnresolvedImplementation() // Should not add import
+    var unresolved: UnresolvedInterface<UnresolvedGeneric?> = UnresolvedImplementation() // Should not add import
 
 
     var hashMapOfNotImported: Map<ToBeImportedJava, ToBeImportedKotlin> = HashMap()
@@ -18,11 +18,11 @@ class Target {
 
     internal fun acceptJavaClass(tbi: ToBeImportedJava?) {}
 
-    var ambiguousKotlin: IAmbiguousKotlin? = AmbiguousKotlin() // Should not add import in case of 2 declarations in Kotlin
+    var ambiguousKotlin: IAmbiguousKotlin = AmbiguousKotlin() // Should not add import in case of 2 declarations in Kotlin
 
-    var ambiguous: IAmbiguous? = Ambiguous() // Should not add import in case of ambiguous declarations in Kotlin and in Java
+    var ambiguous: IAmbiguous = Ambiguous() // Should not add import in case of ambiguous declarations in Kotlin and in Java
 
-    var ambiguousJava: IAmbiguousJava? = AmbiguousJava()  // Should not add import in case of 2 declarations in Java
+    var ambiguousJava: IAmbiguousJava = AmbiguousJava()  // Should not add import in case of 2 declarations in Java
 
 
     internal fun workWithStatics() {

nj2k/testData/copyPastePlainText/KT13529_1.expected.kt

@@ -3,5 +3,5 @@ import java.util.ArrayList
 
 
 fun foo() {
-    bar(/*comment*/ArrayList<String>())
+    bar(/*comment*/ArrayList<String?>())
 }

nj2k/testData/copyPastePlainText/PostProcessing.expected.kt

@@ -6,7 +6,7 @@ import java.util.ArrayList
 
 class JavaClass {
     internal fun foo(file: File?, target: List<String?>?) {
-        val list = ArrayList<String?>()
+        val list = ArrayList<String>()
         if (file != null) {
             list.add(file.name)
         }

nj2k/testData/inference/common/arrayAssignment.kt

@@ -0,0 +1,8 @@
+fun test() {
+    val x: /*T2@*/Array</*T1@*/Int> = arrayOf</*T0@*/Int>()/*Array<T0@Int>*/
+    val y: /*T4@*/Array</*T3@*/Int> = x/*T2@Array<T1@Int>*/
+}
+
+//T1 := T0 due to 'INITIALIZER'
+//T3 := T1 due to 'INITIALIZER'
+//T2 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/arrayOfArrays.kt

@@ -0,0 +1,16 @@
+class Test {
+    fun foo() {
+        val x: /*T5@*/Array</*T4@*/Array</*T3@*/Int>> =
+            Array</*T2@*/Array</*T1@*/Int>>(1/*LIT*/, {
+                arrayOf</*T0@*/Int>(2/*LIT*/)/*Array<T0@Int>*/
+            }/*Function0<Int, T6@Array<T7@Int>>*/
+        )/*Array<T2@Array<T1@Int>>*/
+    }
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//T7 := T0 due to 'RETURN'
+//T1 := T7 due to 'PARAMETER'
+//T6 <: T2 due to 'PARAMETER'
+//T3 := T1 due to 'INITIALIZER'
+//T4 := T2 due to 'INITIALIZER'

nj2k/testData/inference/common/callFunctionWithTypeParamFromOuterScope.kt

@@ -0,0 +1,12 @@
+class X<T> {
+    fun x(): /*T1@*/List</*T0@*/T> {
+        TODO()
+    }
+
+    fun y() {
+        val a: /*T3@*/List</*T2@*/T> = x()/*T1@List<T0@T>*/
+    }
+}
+
+//T0 <: T2 due to 'INITIALIZER'
+//T1 <: T3 due to 'INITIALIZER'

nj2k/testData/inference/common/callWithTypeParams.kt

@@ -0,0 +1,9 @@
+fun test() {
+    foo</*T1@*/Int>(
+        listOf</*T0@*/Int>()/*List<T0@Int>*/
+    )
+}
+
+fun <T> foo (x: /*T3@*/List</*T2@*/T>) {}
+
+//T0 <: T1 due to 'PARAMETER'

nj2k/testData/inference/common/constructorCall.kt

@@ -0,0 +1,15 @@
+fun test() {
+    val x: /*T2@*/X</*T1@*/Int> = X</*T0@*/Int>(10/*LIT*/)/*X<T0@Int>*/
+    val x: /*T5@*/X</*T4@*/Int> = X</*T3@*/Int>(10/*LIT*/, 20/*LIT*/)/*X<T3@Int>*/
+}
+
+class X<T>(x: /*T6@*/T) {
+    constructor(x: /*T7@*/T, y: /*T8@*/Int): this(x/*T7@T*/)
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//T1 := T0 due to 'INITIALIZER'
+//LOWER <: T3 due to 'PARAMETER'
+//LOWER <: T8 due to 'PARAMETER'
+//T4 := T3 due to 'INITIALIZER'
+//T7 <: T6 due to 'PARAMETER'

nj2k/testData/inference/common/delegationConstructorCall.kt

@@ -0,0 +1,5 @@
+class X<T>(x: /*T0@*/T) {
+    constructor(x: /*T1@*/T, y: /*T2@*/Int): this(x/*T1@T*/)
+}
+
+//T1 <: T0 due to 'PARAMETER'

nj2k/testData/inference/common/elementOfArrayAssignment.kt

@@ -0,0 +1,14 @@
+fun test() {
+    val x: /*T4@*/Array</*T3@*/Array</*T2@*/Int>> = arrayOf</*T1@*/Array</*T0@*/Int>>()/*Array<T1@Array<T0@Int>>*/
+    val y: /*T6@*/Array</*T5@*/Int> = x/*T4@Array<T3@Array<T2@Int>>*/.get(0/*LIT*/)/*T3@Array<T2@Int>*/
+    val z: /*T7@*/Int = y/*T6@Array<T5@Int>*/.get(0/*LIT*/)/*T5@Int*/
+}
+
+//T2 := T0 due to 'INITIALIZER'
+//T3 := T1 due to 'INITIALIZER'
+//T2 := T2 due to 'RECEIVER_PARAMETER'
+//T3 := T3 due to 'RECEIVER_PARAMETER'
+//T5 := T2 due to 'INITIALIZER'
+//T3 <: T6 due to 'INITIALIZER'
+//T5 := T5 due to 'RECEIVER_PARAMETER'
+//T5 <: T7 due to 'INITIALIZER'

nj2k/testData/inference/common/elementOfListAssignment.kt

@@ -0,0 +1,14 @@
+fun test() {
+    val x: /*T4@*/List</*T3@*/List</*T2@*/Int>> = listOf</*T1@*/List</*T0@*/Int>>()/*List<T1@List<T0@Int>>*/
+    val y: /*T6@*/List</*T5@*/Int> = x/*T4@List<T3@List<T2@Int>>*/.get(0/*LIT*/)/*T3@List<T2@Int>*/
+    val z: /*T7@*/Int = y/*T6@List<T5@Int>*/.get(0/*LIT*/)/*T5@Int*/
+}
+
+//T0 <: T2 due to 'INITIALIZER'
+//T1 <: T3 due to 'INITIALIZER'
+//T2 <: T2 due to 'RECEIVER_PARAMETER'
+//T3 <: T3 due to 'RECEIVER_PARAMETER'
+//T2 <: T5 due to 'INITIALIZER'
+//T3 <: T6 due to 'INITIALIZER'
+//T5 <: T5 due to 'RECEIVER_PARAMETER'
+//T5 <: T7 due to 'INITIALIZER'

nj2k/testData/inference/common/forLoop.kt

@@ -0,0 +1,10 @@
+fun test() {
+    val x: /*T2@*/List</*T1@*/String> = listOf</*T0@*/String>()/*List<T0@String>*/
+    for (y: /*T3@*/String in x/*T2@List<T1@String>*/) {
+        val z: /*T4@*/String = x/*T2@List<T1@String>*/
+    }
+}
+
+//T0 <: T1 due to 'INITIALIZER'
+//T2 <: T4 due to 'INITIALIZER'
+//T3 <: T1 due to 'ASSIGNMENT'

nj2k/testData/inference/common/functionCall.kt

@@ -0,0 +1,10 @@
+fun test() {
+    val x: /*T1@*/List</*T0@*/Int> = nya()/*T3@List<T2@Int>*/
+}
+
+fun nya(): /*T3@*/List</*T2@*/Int> {
+    TODO()
+}
+
+//T2 <: T0 due to 'INITIALIZER'
+//T3 <: T1 due to 'INITIALIZER'

nj2k/testData/inference/common/functionReturn.kt

@@ -0,0 +1,7 @@
+fun f(): /*T1@*/Int {
+    val x: /*T0@*/Int = 42/*LIT*/
+    return x/*T0@Int*/
+}
+
+//LOWER <: T0 due to 'INITIALIZER'
+//T0 <: T1 due to 'RETURN'

nj2k/testData/inference/common/functionWithTypeParamCall.kt

@@ -0,0 +1,11 @@
+fun test() {
+    val x: /*T3@*/Map</*T1@*/String, /*T2@*/Int> = nya</*T0@*/String>()/*T6@Map<T0@String, T5@Int>*/
+}
+
+fun <T> nya(): /*T6@*/Map</*T4@*/T, /*T5@*/Int> {
+    TODO()
+}
+
+//T1 := T0 due to 'INITIALIZER'
+//T5 <: T2 due to 'INITIALIZER'
+//T6 <: T3 due to 'INITIALIZER'

nj2k/testData/inference/common/lambdaAsParameter.kt

@@ -0,0 +1,11 @@
+fun test() {
+    nya</*T2@*/Boolean>({ a: /*T0@*/Int, b: /*T1@*/Boolean -> ""/*LIT*/ }/*Function2<T0@Int, T1@Boolean, T7@String>*/)
+}
+
+fun <T> nya(x: /*T6@*/Function2</*T3@*/T, /*T4@*/Boolean, /*T5@*/String>) {
+}
+
+//LOWER <: T7 due to 'RETURN'
+//T2 <: T0 due to 'PARAMETER'
+//T4 <: T1 due to 'PARAMETER'
+//T7 <: T5 due to 'PARAMETER'

nj2k/testData/inference/common/lambdaAssign.kt

@@ -0,0 +1,8 @@
+fun test() {
+    val x: /*T5@*/Function2</*T2@*/Int, /*T3@*/String, /*T4@*/Boolean> = { a: /*T0@*/Int, b: /*T1@*/String -> true/*LIT*/ }/*Function2<T0@Int, T1@String, T6@Boolean>*/
+}
+
+//LOWER <: T6 due to 'RETURN'
+//T2 <: T0 due to 'INITIALIZER'
+//T3 <: T1 due to 'INITIALIZER'
+//T6 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/lambdaImplicitReturn.kt

@@ -0,0 +1,12 @@
+fun test() {
+    val x: /*T6@*/Function2</*T3@*/Int, /*T4@*/String, /*T5@*/Boolean> = { a: /*T0@*/Int, b: /*T1@*/String ->
+        val a: /*T2@*/Boolean = true/*LIT*/
+        a/*T2@Boolean*/
+    }/*Function2<T0@Int, T1@String, T7@Boolean>*/
+}
+
+//LOWER <: T2 due to 'INITIALIZER'
+//T2 <: T7 due to 'RETURN'
+//T3 <: T0 due to 'INITIALIZER'
+//T4 <: T1 due to 'INITIALIZER'
+//T7 <: T5 due to 'INITIALIZER'

nj2k/testData/inference/common/lambdaReturn.kt

@@ -0,0 +1,21 @@
+class Test {
+    fun foo1(r: /*T2@*/Function1</*T0@*/Int, /*T1@*/String>) {}
+    fun foo() {
+        foo1 { i: /*T3@*/Int ->
+            val str: /*T4@*/String = ""/*LIT*/
+            val str2: /*T5@*/String = ""/*LIT*/
+
+            if (i > 1) {
+                return@foo1 str/*T4@String*/
+            }
+            str2/*T5@String*/
+        }/*Function1<T3@Int, T6@String>*/
+    }
+}
+
+//LOWER <: T4 due to 'INITIALIZER'
+//LOWER <: T5 due to 'INITIALIZER'
+//T4 <: T6 due to 'RETURN'
+//T5 <: T6 due to 'RETURN'
+//T0 <: T3 due to 'PARAMETER'
+//T6 <: T1 due to 'PARAMETER'

nj2k/testData/inference/common/listAssignment.kt

@@ -0,0 +1,8 @@
+fun test() {
+    val x: /*T2@*/List</*T1@*/Int> = listOf</*T0@*/Int>()/*List<T0@Int>*/
+    val y: /*T4@*/List</*T3@*/Int> = x/*T2@List<T1@Int>*/
+}
+
+//T0 <: T1 due to 'INITIALIZER'
+//T1 <: T3 due to 'INITIALIZER'
+//T2 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/listGenerator.kt

@@ -0,0 +1,7 @@
+fun test() {
+    val x: /*T2@*/List</*T1@*/Int> = List</*T0@*/Int>(10/*LIT*/, { 10/*LIT*/ }/*Function0<Int, T3@Int>*/)/*List<T0@Int>*/
+}
+
+//LOWER <: T3 due to 'RETURN'
+//T3 <: T0 due to 'PARAMETER'
+//T0 <: T1 due to 'INITIALIZER'

nj2k/testData/inference/common/listOfLists.kt

@@ -0,0 +1,12 @@
+fun foo() {
+    val a: /*T5@*/List</*T4@*/List</*T3@*/Int>> = listOf</*T2@*/List</*T1@*/Int>>(
+        listOf</*T0@*/Int>(
+            1/*LIT*/
+        )/*List<T0@Int>*/
+    )/*List<T2@List<T1@Int>>*/
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//T0 <: T1 due to 'PARAMETER'
+//T1 <: T3 due to 'INITIALIZER'
+//T2 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/listOfListsGenerator.kt

@@ -0,0 +1,16 @@
+fun test() {
+    val x: /*T5@*/List</*T4@*/List</*T3@*/Int>> = List</*T2@*/List</*T1@*/Int>>(13/*LIT*/, {
+             List</*T0@*/Int>(7/*LIT*/, {
+                 666/*LIT*/
+             }/*Function0<Int, T6@Int>*/)/*List<T0@Int>*/
+         }/*Function0<Int, T7@List<T8@Int>>*/
+    )/*List<T2@List<T1@Int>>*/
+}
+
+//LOWER <: T6 due to 'RETURN'
+//T6 <: T0 due to 'PARAMETER'
+//T0 <: T8 due to 'RETURN'
+//T8 <: T1 due to 'PARAMETER'
+//T7 <: T2 due to 'PARAMETER'
+//T1 <: T3 due to 'INITIALIZER'
+//T2 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/memberCall.kt

@@ -0,0 +1,16 @@
+fun test() {
+    val x: /*T2@*/X</*T1@*/Int> = X</*T0@*/Int>()/*X<T0@Int>*/
+    val y: /*T5@*/Map</*T3@*/Int, /*T4@*/String> = x/*T2@X<T1@Int>*/.foo()/*T8@Map<T1@Int, T7@String>*/
+}
+
+class X<T> {
+    fun foo(): /*T8@*/Map</*T6@*/T, /*T7@*/String> {
+        TODO()
+    }
+}
+
+//T1 := T0 due to 'INITIALIZER'
+//T1 := T1 due to 'RECEIVER_PARAMETER'
+//T3 := T1 due to 'INITIALIZER'
+//T7 <: T4 due to 'INITIALIZER'
+//T8 <: T5 due to 'INITIALIZER'

nj2k/testData/inference/common/returnFromLambda.kt

@@ -0,0 +1,16 @@
+fun test() {
+    val x: /*T6@*/Function2</*T3@*/Int, /*T4@*/String, /*T5@*/Boolean> = l@{ a: /*T0@*/Int, b: /*T1@*/String ->
+        val y: /*T2@*/Boolean = true/*LIT*/
+        if (a == 3) {
+            return@l y/*T2@Boolean*/
+        }
+        true/*LIT*/
+    }/*Function2<T0@Int, T1@String, T7@Boolean>*//*Function2<T0@Int, T1@String, T7@Boolean>*/
+}
+
+//LOWER <: T2 due to 'INITIALIZER'
+//T2 <: T7 due to 'RETURN'
+//LOWER <: T7 due to 'RETURN'
+//T3 <: T0 due to 'INITIALIZER'
+//T4 <: T1 due to 'INITIALIZER'
+//T7 <: T5 due to 'INITIALIZER'

nj2k/testData/inference/common/sequenceOfCalls.kt

@@ -0,0 +1,9 @@
+fun a(lst: /*T1@*/List</*T0@*/String>) {
+    val newList: /*T5@*/List</*T4@*/String> = lst/*T1@List<T0@String>*/
+        .asSequence</*T2@*/String>()/*Sequence<T2@String>*/
+        .toList</*T3@*/String>()/*List<T3@String>*/
+}
+
+//T0 <: T2 due to 'RECEIVER_PARAMETER'
+//T2 <: T3 due to 'RECEIVER_PARAMETER'
+//T3 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/common/sequenceOfCallsWIthLambda.kt

@@ -0,0 +1,14 @@
+fun a(lst: /*T1@*/List</*T0@*/String>) {
+    val newList: /*T8@*/List</*T7@*/Int> = lst/*T1@List<T0@String>*/
+        .asSequence</*T2@*/String>()/*Sequence<T2@String>*/
+        .map</*T4@*/String, /*T5@*/Int>({ x: /*T3@*/String -> 1/*LIT*/ }/*Function1<T3@String, T9@Int>*/)/*Sequence<T5@Int>*/
+        .toList</*T6@*/Int>()/*List<T6@Int>*/
+}
+
+//T0 <: T2 due to 'RECEIVER_PARAMETER'
+//LOWER <: T9 due to 'RETURN'
+//T2 <: T4 due to 'RECEIVER_PARAMETER'
+//T4 <: T3 due to 'PARAMETER'
+//T9 <: T5 due to 'PARAMETER'
+//T5 <: T6 due to 'RECEIVER_PARAMETER'
+//T6 <: T7 due to 'INITIALIZER'

nj2k/testData/inference/common/simpleAssignment.kt

@@ -0,0 +1,9 @@
+fun test() {
+    val x: /*T0@*/Int = 10/*LIT*/
+    val y: /*T1@*/Int = x/*T0@Int*/
+    val z: /*T2@*/Int = y/*T1@Int*/
+}
+
+//LOWER <: T0 due to 'INITIALIZER'
+//T0 <: T1 due to 'INITIALIZER'
+//T1 <: T2 due to 'INITIALIZER'

nj2k/testData/inference/common/superCall.kt

@@ -0,0 +1,14 @@
+open class A<T> {
+    open fun foo(x: /*T0@*/T, y: /*T2@*/List</*T1@*/T>) {
+    }
+}
+
+class B : A</*T6@*/Int>() {
+    override fun foo(x: /*T3@*/Int, y: /*T5@*/List</*T4@*/Int>) {
+        super/*LIT*/.foo(x/*T3@Int*/, y/*T5@List<T4@Int>*/)
+    }
+}
+
+//T3 := T6 due to 'SUPER_DECLARATION'
+//T4 := T6 due to 'SUPER_DECLARATION'
+//T2 := T5 due to 'SUPER_DECLARATION'

nj2k/testData/inference/common/superConstuctorCall.kt

@@ -0,0 +1,7 @@
+open class X<T>(x: /*T0@*/T) {
+}
+
+class Y<T>(x: /*T1@*/T) : X</*T2@*/T>(x/*T1@T*/) {
+}
+
+//T1 <: T0 due to 'PARAMETER'

nj2k/testData/inference/common/superFunctionReturnTypeWithTypeParameters.kt

@@ -0,0 +1,15 @@
+interface A<T, S> {
+    fun foo(): /*T3@*/List</*T2@*/Map</*T0@*/T, /*T1@*/S>>
+}
+
+
+open class B<X> : A</*T8@*/X, /*T9@*/Int> {
+    override fun foo(): /*T7@*/List</*T6@*/Map</*T4@*/X, /*T5@*/Int>> {
+        TODO()
+    }
+}
+
+//T4 := T8 due to 'SUPER_DECLARATION'
+//T5 := T9 due to 'SUPER_DECLARATION'
+//T2 := T6 due to 'SUPER_DECLARATION'
+//T3 := T7 due to 'SUPER_DECLARATION'

nj2k/testData/inference/common/superFunctionReturnTypeWithTypeParametersSubstitution.kt

@@ -0,0 +1,13 @@
+open class A<T> {
+    open fun foo(): /*T0@*/T {
+        TODO()
+    }
+}
+
+class B<T> : A</*T2@*/Int>() {
+    override fun foo(): /*T1@*/Int {
+        TODO()
+    }
+}
+
+//T1 := T2 due to 'SUPER_DECLARATION'

nj2k/testData/inference/common/superFunctionType.kt

@@ -0,0 +1,13 @@
+open class A {
+    open fun foo(): /*T0@*/String {
+        TODO()
+    }
+}
+
+class B : A() {
+    override fun foo(): /*T1@*/String {
+        TODO()
+    }
+}
+
+//T0 := T1 due to 'SUPER_DECLARATION'

nj2k/testData/inference/common/typeParamsBounds.kt

@@ -0,0 +1,5 @@
+class Test {
+    fun <X : /*T0@*/Any> x() {
+    }
+}
+

nj2k/testData/inference/common/varargsInCall.kt

@@ -0,0 +1,14 @@
+fun test() {
+    val x: /*T0@*/String = ""/*LIT*/
+    val y: /*T1@*/String = ""/*LIT*/
+    val z: /*T2@*/String = ""/*LIT*/
+    val e: /*T5@*/List</*T4@*/String> = listOf</*T3@*/String>(x/*T0@String*/, y/*T1@String*/, z/*T2@String*/)/*List<T3@String>*/
+}
+
+//LOWER <: T0 due to 'INITIALIZER'
+//LOWER <: T1 due to 'INITIALIZER'
+//LOWER <: T2 due to 'INITIALIZER'
+//T0 <: T3 due to 'PARAMETER'
+//T1 <: T3 due to 'PARAMETER'
+//T2 <: T3 due to 'PARAMETER'
+//T3 <: T4 due to 'INITIALIZER'

nj2k/testData/inference/nullability/arrayOfArraysOfNull.kt

@@ -0,0 +1,10 @@
+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*/)
+    }
+}
+
+//T4 := UPPER due to 'RETURN'
+//LOWER <: T3 due to 'RETURN'
+//T1 := T4 due to 'PARAMETER'
+//T3 <: T2 due to 'PARAMETER'

nj2k/testData/inference/nullability/arrayOfNulls.kt

@@ -0,0 +1,6 @@
+fun test() {
+    val x: /*T2@*/Array</*T1@*/Int?> = arrayOfNulls</*T0@*/Int?>(10/*LIT*/)/*Array<T0@Int!!U>!!L*/
+}
+
+//T1 := UPPER due to 'INITIALIZER'
+//LOWER <: T2 due to 'INITIALIZER'

nj2k/testData/inference/nullability/binaryExpressionOperand.kt

@@ -0,0 +1,7 @@
+fun test() {
+    val x: /*T0@*/Int = 10/*LIT*/
+    x/*T0@Int*/ > 0/*LIT*/
+}
+
+//LOWER <: T0 due to 'INITIALIZER'
+//T0 := LOWER due to 'USE_AS_RECEIVER'

nj2k/testData/inference/nullability/callExternallyAnnotatedJavaFunction.kt

@@ -0,0 +1,11 @@
+import java.util.Arrays.asList
+
+fun test() {
+    val x: /*T2@*/List</*T1@*/Int> = asList</*T0@*/Int>(1/*LIT*/)/*MutableList<T0@Int>!!L*/
+    val i: /*T3@*/Int = Integer/*LIT*/.valueOf(""/*LIT*/)/*Int!!L*/
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//T1 := T0 due to 'INITIALIZER'
+//LOWER <: T2 due to 'INITIALIZER'
+//LOWER <: T3 due to 'INITIALIZER'

nj2k/testData/inference/nullability/classTypeParameters.kt

@@ -0,0 +1,27 @@
+open class A<T> {
+    open fun foo(): /*T3@*/Map</*T0@*/T, /*T2@*/List</*T1@*/T>>? {
+        TODO()
+    }
+
+    open fun bar(): /*T4@*/T? {
+        return null/*NULL!!U*/
+    }
+}
+
+class B : A</*T10@*/Int>() {
+    override fun foo(): /*T8@*/Map</*T5@*/Int, /*T7@*/List</*T6@*/Int>>? {
+        return null/*NULL!!U*/
+    }
+    override fun bar(): /*T9@*/Int {
+        return 42/*LIT*/
+    }
+}
+
+//UPPER <: T4 due to 'RETURN'
+//UPPER <: T8 due to 'RETURN'
+//T5 := T10 due to 'SUPER_DECLARATION'
+//T6 := T10 due to 'SUPER_DECLARATION'
+//T2 := T7 due to 'SUPER_DECLARATION'
+//T3 := T8 due to 'SUPER_DECLARATION'
+//LOWER <: T9 due to 'RETURN'
+//T9 := T10 due to 'SUPER_DECLARATION'

nj2k/testData/inference/nullability/compareWithNull.kt

@@ -0,0 +1,19 @@
+fun a(): /*T0@*/Int? {
+    return 42/*LIT*/
+}
+
+val b: /*T1@*/Int? = 2/*LIT*/
+
+fun c(p: /*T2@*/Int?) {
+    if (p/*T2@Int*/ == null/*LIT*/);
+}
+
+fun check() {
+    if (a()/*T0@Int*/ == null/*LIT*/ || b/*T1@Int*/ == null/*LIT*//*LIT*/);
+}
+
+//LOWER <: T0 due to 'RETURN'
+//LOWER <: T1 due to 'INITIALIZER'
+//T2 := UPPER due to 'COMPARE_WITH_NULL'
+//T0 := UPPER due to 'COMPARE_WITH_NULL'
+//T1 := UPPER due to 'COMPARE_WITH_NULL'

nj2k/testData/inference/nullability/forcedNullability.kt

@@ -0,0 +1,9 @@
+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*/
+}
+
+//T0 := T0 due to 'RECEIVER_PARAMETER'
+//T1 <: T1 due to 'RECEIVER_PARAMETER'
+//LOWER <: T0 due to 'PARAMETER'
+//T2 := LOWER due to 'USE_AS_RECEIVER'
+//UPPER <: T3 due to 'RETURN'

nj2k/testData/inference/nullability/functionTypeParameterNullability.kt

@@ -0,0 +1,20 @@
+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*/
+    val lst2: /*T11@*/List</*T10@*/Int> = listOf</*T9@*/Int>(1/*LIT*/)/*List<T9@Int>!!L*/
+    foo</*T12@*/Int?, /*T13@*/Int?, /*T14@*/Int, /*T15@*/String>(null/*NULL!!U*/, lst/*T8@List<T7@Int>*/, lst2/*T11@List<T10@Int>*/, "nya"/*LIT*/)
+}
+
+//UPPER <: T6 due to 'PARAMETER'
+//T6 <: T7 due to 'INITIALIZER'
+//LOWER <: T8 due to 'INITIALIZER'
+//LOWER <: T9 due to 'PARAMETER'
+//T9 <: T10 due to 'INITIALIZER'
+//LOWER <: T11 due to 'INITIALIZER'
+//UPPER <: T12 due to 'PARAMETER'
+//T7 <: T13 due to 'PARAMETER'
+//T8 <: T2 due to 'PARAMETER'
+//T10 <: T14 due to 'PARAMETER'
+//T11 <: T4 due to 'PARAMETER'
+//LOWER <: T15 due to 'PARAMETER'

nj2k/testData/inference/nullability/functions.kt

@@ -0,0 +1,40 @@
+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() {
+    notNullParameters({ i: /*T12@*/Int, j: /*T13@*/Int ->
+                          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 ->
+                          if (i/*T14@Int*/ == null/*LIT*/) ""/*LIT*/ else ""/*LIT*/
+                      }/*Function2<T14@Int, T15@Int, T19@String>!!L*/)
+
+    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*/)
+}
+
+//T12 := LOWER due to 'USE_AS_RECEIVER'
+//T13 := LOWER due to 'USE_AS_RECEIVER'
+//LOWER <: T18 due to 'RETURN'
+//T0 <: T12 due to 'PARAMETER'
+//T1 <: T13 due to 'PARAMETER'
+//T18 <: T2 due to 'PARAMETER'
+//LOWER <: T3 due to 'PARAMETER'
+//T14 := UPPER due to 'COMPARE_WITH_NULL'
+//LOWER <: T19 due to 'RETURN'
+//T4 <: T14 due to 'PARAMETER'
+//T5 <: T15 due to 'PARAMETER'
+//T19 <: T6 due to 'PARAMETER'
+//LOWER <: T7 due to 'PARAMETER'
+//T16 := LOWER due to 'USE_AS_RECEIVER'
+//UPPER <: T20 due to 'RETURN'
+//LOWER <: T20 due to 'RETURN'
+//T8 <: T16 due to 'PARAMETER'
+//T9 <: T17 due to 'PARAMETER'
+//T20 <: T10 due to 'PARAMETER'
+//LOWER <: T11 due to 'PARAMETER'

nj2k/testData/inference/nullability/ifCondition.kt

@@ -0,0 +1,5 @@
+fun test(a: /*T0@*/Boolean) {
+    if (a/*T0@Boolean*/) {}
+}
+
+//T0 := LOWER due to 'USE_AS_RECEIVER'

nj2k/testData/inference/nullability/javaStream.kt

@@ -0,0 +1,25 @@
+// RUNTIME_WITH_FULL_JDK
+
+import java.util.stream.Collector
+import java.util.stream.Collectors
+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>*/
+
+}
+
+//T0 <: T0 due to 'RECEIVER_PARAMETER'
+//T1 := LOWER due to 'USE_AS_RECEIVER'
+//T2 := LOWER due to 'USE_AS_RECEIVER'
+//LOWER <: T10 due to 'RETURN'
+//T0 := T0 due to 'RECEIVER_PARAMETER'
+//T0 <: T2 due to 'PARAMETER'
+//T10 <: T3 due to 'PARAMETER'
+//T3 := T3 due to 'RECEIVER_PARAMETER'
+//T3 := T4 due to 'PARAMETER'
+//T5 := T4 due to 'PARAMETER'
+//T5 <: T8 due to 'INITIALIZER'
+//T6 <: T9 due to 'INITIALIZER'

nj2k/testData/inference/nullability/lambdaReturnNull.kt

@@ -0,0 +1,23 @@
+class Test {
+    fun foo1(r: /*T2@*/Function1</*T0@*/Int, /*T1@*/String?>) {}
+    fun foo() {
+        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*/
+                 }
+                 ""/*LIT*/
+             }/*Function1<T4@Int, T6@String>!!L*/)
+    }
+}
+
+//LOWER <: T5 due to 'RETURN'
+//T0 <: T3 due to 'PARAMETER'
+//T5 <: T1 due to 'PARAMETER'
+//LOWER <: T2 due to 'PARAMETER'
+//T4 := LOWER due to 'USE_AS_RECEIVER'
+//UPPER <: T6 due to 'RETURN'
+//LOWER <: T6 due to 'RETURN'
+//T0 <: T4 due to 'PARAMETER'
+//T6 <: T1 due to 'PARAMETER'
+//LOWER <: T2 due to 'PARAMETER'

nj2k/testData/inference/nullability/listOfWithNullLiteral.kt

@@ -0,0 +1,9 @@
+fun test() {
+    val x: /*T2@*/List</*T1@*/Int?> = listOf</*T0@*/Int?>(1/*LIT*/, null/*NULL!!U*/, 3/*LIT*/)/*List<T0@Int>!!L*/
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//UPPER <: T0 due to 'PARAMETER'
+//LOWER <: T0 due to 'PARAMETER'
+//T0 <: T1 due to 'INITIALIZER'
+//LOWER <: T2 due to 'INITIALIZER'

nj2k/testData/inference/nullability/loopIterator.kt

@@ -0,0 +1,8 @@
+fun test(a: /*T1@*/List</*T0@*/Int>) {
+    for (i: /*T2@*/Int in a/*T1@List<T0@Int>*/) {
+
+    }
+}
+
+//T2 <: T0 due to 'ASSIGNMENT'
+//T1 := LOWER due to 'USE_AS_RECEIVER'

nj2k/testData/inference/nullability/loops.kt

@@ -0,0 +1,31 @@
+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*/) {
+            println(value/*T10@Int*/ + 1/*LIT*//*LIT*/)
+        }
+    }
+
+    for (i: /*T11@*/Int in list1/*T4@List<T3@Int>*/) {
+        i/*T11@Int*/ + 1/*LIT*/
+    }
+
+    for (i: /*T12@*/String? in list2/*T6@List<T5@String>*/) {
+        i/*T12@String*/ == null
+    }
+}
+
+//T2 := LOWER due to 'USE_AS_RECEIVER'
+//T9 := LOWER due to 'USE_AS_RECEIVER'
+//T8 <: T10 due to 'INITIALIZER'
+//T9 := LOWER due to 'USE_AS_RECEIVER'
+//T7 := UPPER due to 'COMPARE_WITH_NULL'
+//T10 := LOWER due to 'USE_AS_RECEIVER'
+//T0 := T7 due to 'ASSIGNMENT'
+//T1 := T8 due to 'ASSIGNMENT'
+//T11 := LOWER due to 'USE_AS_RECEIVER'
+//T11 <: T3 due to 'ASSIGNMENT'
+//T4 := LOWER due to 'USE_AS_RECEIVER'
+//T12 := UPPER due to 'COMPARE_WITH_NULL'
+//T12 <: T5 due to 'ASSIGNMENT'
+//T6 := LOWER due to 'USE_AS_RECEIVER'

nj2k/testData/inference/nullability/notNullCallSequence.kt

@@ -0,0 +1,16 @@
+// RUNTIME_WITH_FULL_JDK
+
+fun main() {
+    val list: /*T5@*/List</*T4@*/String?> =
+        listOf</*T0@*/String?>(""/*LIT*/, null/*NULL!!U*/)/*List<T0@String>!!L*/
+            .map</*T2@*/String?, /*T3@*/String?>({ x: /*T1@*/String? -> x/*T1@String*/ }/*Function1<T1@String, T6@String>!!L*/)/*List<T3@String>!!L*/
+}
+
+//LOWER <: T0 due to 'PARAMETER'
+//UPPER <: T0 due to 'PARAMETER'
+//T1 <: T6 due to 'RETURN'
+//T0 <: T2 due to 'RECEIVER_PARAMETER'
+//T2 <: T1 due to 'PARAMETER'
+//T6 <: T3 due to 'PARAMETER'
+//T3 <: T4 due to 'INITIALIZER'
+//LOWER <: T5 due to 'INITIALIZER'