New J2K: fix NPEs in nullability analysis

#KT-31817 fixed

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

@@ -30,7 +30,6 @@ internal class BoundTypeStorage(private val analysisAnalysisContext: AnalysisCon
 
     fun boundTypeFor(expression: KtExpression): BoundType =
         cache.getOrPut(expression) {
-            if (expression is KtParenthesizedExpression) return@getOrPut boundTypeFor(expression.expression!!)
             val boundType =
                 when (expression) {
                     is KtParenthesizedExpression -> expression.expression?.let { boundTypeFor(it) }
@@ -131,13 +130,18 @@ internal class BoundTypeStorage(private val analysisAnalysisContext: AnalysisCon
         val descriptor =
             getResolvedCall(bindingContext)?.candidateDescriptor?.original?.safeAs<CallableDescriptor>() ?: return null
         val typeParameters =
-            if (this is KtCallElement) {
-                typeArguments.mapIndexed { index, typeArgument ->
-                    //TODO better check
-                    descriptor.typeParameters[index] to
-                            analysisAnalysisContext.typeElementToTypeVariable.getValue(typeArgument.typeReference?.typeElement!!)
-                }.toMap()
-            } else emptyMap()
+            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)
     }
 

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

@@ -80,7 +80,7 @@ internal class ConstraintsCollector(
             }
 
             expression is KtBinaryExpression && expression.asAssignment() != null -> {
-                expression.right?.addSubtypeNullabilityConstraint(expression.left!!, ConstraintCameFrom.ASSIGNMENT_TARGET)
+                expression.right?.addSubtypeNullabilityConstraint(expression.left ?: return, ConstraintCameFrom.ASSIGNMENT_TARGET)
             }
 
             expression is KtBinaryExpression && expression.isComaprationWithNull() -> {
@@ -152,7 +152,7 @@ internal class ConstraintsCollector(
                         analysisContext.typeElementToTypeVariable[typeElement]
                     }
                 if (loopParameterTypeVariable != null) {
-                    val loopRangeBoundType = boundTypeStorage.boundTypeFor(expression.loopRange!!)
+                    val loopRangeBoundType = boundTypeStorage.boundTypeFor(expression.loopRange ?: return)
                     val loopRangeType = expression.loopRange?.getType(expression.analyze()) ?: return
                     val loopRangeItemType = loopRangeType
                         .constructor
@@ -280,7 +280,7 @@ internal class ConstraintsCollector(
                 }
             }?.let { type ->
                 boundTypeStorage
-                    .boundTypeForType(type, receiverBoundType, callExpression.typeArgumentsDescriptors(descriptor))
+                    .boundTypeForType(type, receiverBoundType, callExpression.typeArgumentsDescriptors(descriptor).orEmpty())
             }
 
 
@@ -299,9 +299,12 @@ internal class ConstraintsCollector(
         }
     }
 
-    private fun KtCallExpression.typeArgumentsDescriptors(descriptor: CallableDescriptor): Map<TypeParameterDescriptor, TypeVariable> =
-        descriptor.typeParameters.zip(typeArguments) { typeParameter, typeArgument ->
-            typeParameter to
-                    this@ConstraintsCollector.analysisContext.typeElementToTypeVariable.getValue(typeArgument.typeReference?.typeElement!!)
+    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

@@ -50,7 +50,7 @@ internal class ContextCreator(
                 if (typeArguments.isNotEmpty())
                     FunctionCallTypeArgumentTarget(
                         this,
-                        typeArguments.map { it.typeReference?.typeElement?.asTypeVariable()!! }
+                        typeArguments.map { it.typeReference?.typeElement?.asTypeVariable() ?: return null }
                     )
                 else null
             else -> null

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

@@ -11,7 +11,6 @@ import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiComment
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiElementVisitor
-import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
 import org.jetbrains.kotlin.nj2k.asLabel
 import org.jetbrains.kotlin.nj2k.parentOfType
@@ -29,10 +28,10 @@ internal fun TypeVariable.changeNullability(toNullable: Boolean) {
 internal fun KtTypeElement.changeNullability(toNullable: Boolean) {
     val factory = KtPsiFactory(this)
     if (this is KtNullableType && !toNullable) {
-        replace(factory.createType(innerType!!.text).typeElement!!)
+        replace(factory.createType(innerType?.text ?: return).typeElement ?: return)
     }
     if (this !is KtNullableType && toNullable) {
-        replace(factory.createType("$text?").typeElement!!)
+        replace(factory.createType("$text?").typeElement ?: return)
     }
 }
 
@@ -70,10 +69,10 @@ internal fun KtTypeElement.classReference(): ClassReference {
     return when (target) {
         is KtClassOrObject -> KtClassReference(target)
         is PsiClass -> JavaClassReference(target)
-        is KtTypeAlias -> target.getTypeReference()?.typeElement?.classReference()!!
+        is KtTypeAlias -> target.getTypeReference()?.typeElement?.classReference()
         is KtTypeParameter -> TypeParameterClassReference(target)
-        else -> UnknownClassReference(text)
-    }
+        else -> null
+    } ?: UnknownClassReference(text)
 }
 
 class NullabilityAnalysisFacade(

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

@@ -18,7 +18,8 @@ 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.*
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.isNullable
 import org.jetbrains.kotlin.util.javaslang.getOrNull
 
 internal fun KtExpression.deepestReceiver(): KtExpression =
@@ -52,7 +53,7 @@ internal fun KtExpression.getForcedNullability(): Nullability? {
 }
 
 
-private fun KotlinType.isExternallyAnnotatedNotNull(dataFlowInfo: DataFlowInfo, dataFlowValue: DataFlowValue): Boolean=
+private fun KotlinType.isExternallyAnnotatedNotNull(dataFlowInfo: DataFlowInfo, dataFlowValue: DataFlowValue): Boolean =
     mustNotBeNull()?.isFromJava == true && dataFlowInfo.getStableNullability(dataFlowValue).canBeNull()
 
 private fun IElementType.isEqualsToken() =