FIR DFA: store stability in RealVariable

As part of this change, we also extend the usage of RealVariable in more
places during DFA. Now mutable properties, property with custom getters,
delegated properties, etc are also treatd as a `RealVariable`. In
general this is needed in order to carry out smartcast computation in
order to report `SMARTCAST_IMPOSSIBLE`. It seems to also have side
effects that improves behavior of some test files.

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/FirReturnsImpliesAnalyzer.kt

@@ -156,30 +156,34 @@ object FirReturnsImpliesAnalyzer : FirControlFlowChecker() {
         variableStorage: VariableStorage,
         flow: Flow,
         context: CheckerContext
-    ): MutableTypeStatements? = when (this) {
-        is ConeBinaryLogicExpression -> {
-            val left = left.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
-            val right = right.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
-            if (left != null && right != null) {
-                if (kind == LogicOperationKind.AND) {
-                    left.apply { mergeTypeStatements(right) }
-                } else logicSystem.orForTypeStatements(left, right)
-            } else (left ?: right)
-        }
-        is ConeIsInstancePredicate -> {
+    ): MutableTypeStatements? {
+        fun buildTypeStatements(arg: ConeValueParameterReference, exactType: Boolean, type: ConeKotlinType): MutableTypeStatements? {
             val fir = function.getParameterSymbol(arg.parameterIndex, context).fir
             val realVar = variableStorage.getOrCreateRealVariable(flow, fir.symbol, fir)
-            realVar?.to(simpleTypeStatement(realVar, !isNegated, type))?.let { mutableMapOf(it) }
+                ?.takeIf {
+                    it.stability == PropertyStability.STABLE_VALUE ||
+                            // TODO: consider removing the part below
+                            it.stability == PropertyStability.LOCAL_VAR
+                }
+            return realVar?.to(simpleTypeStatement(realVar, exactType, type))?.let { mutableMapOf(it) }
         }
-        is ConeIsNullPredicate -> {
-            val fir = function.getParameterSymbol(arg.parameterIndex, context).fir
-            val realVar = variableStorage.getOrCreateRealVariable(flow, fir.symbol, fir)
-            realVar?.to(simpleTypeStatement(realVar, isNegated, context.session.builtinTypes.anyType.type))?.let { mutableMapOf(it) }
-        }
-        is ConeLogicalNot -> arg.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
-            ?.mapValuesTo(mutableMapOf()) { (_, value) -> value.invert() }
+        return when (this) {
+            is ConeBinaryLogicExpression -> {
+                val left = left.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
+                val right = right.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
+                if (left != null && right != null) {
+                    if (kind == LogicOperationKind.AND) {
+                        left.apply { mergeTypeStatements(right) }
+                    } else logicSystem.orForTypeStatements(left, right)
+                } else (left ?: right)
+            }
+            is ConeIsInstancePredicate -> buildTypeStatements(arg, !isNegated, type)
+            is ConeIsNullPredicate -> buildTypeStatements(arg, isNegated, context.session.builtinTypes.anyType.type)
+            is ConeLogicalNot -> arg.buildTypeStatements(function, logicSystem, variableStorage, flow, context)
+                ?.mapValuesTo(mutableMapOf()) { (_, value) -> value.invert() }
 
-        else -> null
+            else -> null
+        }
     }
 
     private fun ConeKotlinType.isInapplicableWith(operation: Operation, session: FirSession): Boolean {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ResolveUtils.kt

@@ -10,7 +10,10 @@ import org.jetbrains.kotlin.builtins.functions.FunctionClassKind
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.*
-import org.jetbrains.kotlin.fir.diagnostics.*
+import org.jetbrains.kotlin.fir.diagnostics.ConeDiagnostic
+import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
+import org.jetbrains.kotlin.fir.diagnostics.ConeStubDiagnostic
+import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
 import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.builder.*
 import org.jetbrains.kotlin.fir.references.FirErrorNamedReference
@@ -23,12 +26,12 @@ import org.jetbrains.kotlin.fir.resolve.calls.ImplicitDispatchReceiverValue
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnresolvedNameError
 import org.jetbrains.kotlin.fir.resolve.inference.inferenceComponents
 import org.jetbrains.kotlin.fir.resolve.inference.isBuiltinFunctionalType
-import org.jetbrains.kotlin.fir.resolve.providers.*
+import org.jetbrains.kotlin.fir.resolve.providers.getSymbolByTypeRef
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
 import org.jetbrains.kotlin.fir.resolve.transformers.ensureResolved
 import org.jetbrains.kotlin.fir.scopes.impl.delegatedWrapperData
 import org.jetbrains.kotlin.fir.scopes.impl.importedFromObjectData
-import org.jetbrains.kotlin.fir.symbols.*
+import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
@@ -247,7 +250,8 @@ private fun BodyResolveComponents.typeFromSymbol(symbol: AbstractFirBasedSymbol<
 fun BodyResolveComponents.transformQualifiedAccessUsingSmartcastInfo(
     qualifiedAccessExpression: FirQualifiedAccessExpression
 ): FirQualifiedAccessExpression {
-    val typesFromSmartCast = dataFlowAnalyzer.getTypeUsingSmartcastInfo(qualifiedAccessExpression) ?: return qualifiedAccessExpression
+    val (stability, typesFromSmartCast) = dataFlowAnalyzer.getTypeUsingSmartcastInfo(qualifiedAccessExpression)
+        ?: return qualifiedAccessExpression
     val originalType = qualifiedAccessExpression.resultType.coneType
     // For example, if (x == null) { ... },
     //   we don't want to smartcast to Nothing?, but we want to record the nullability to its own kind of node.
@@ -268,9 +272,11 @@ fun BodyResolveComponents.transformQualifiedAccessUsingSmartcastInfo(
         return buildExpressionWithSmartcastToNull {
             originalExpression = qualifiedAccessExpression
             // TODO: Use Nothing? during resolution?
-            typeRef = intersectedTypeRefWithoutNullableNothing
+            smartcastType = intersectedTypeRefWithoutNullableNothing
             // NB: Nothing? in types from smartcast in DFA is recorded here (and the expression kind itself).
             this.typesFromSmartCast = typesFromSmartCast
+            // TODO: differentiate capture local variable
+            this.smartcastStability = stability.impliedSmartcastStability ?: SmartcastStability.STABLE_VALUE
         }
     }
     val allTypes = typesFromSmartCast.also {
@@ -288,7 +294,8 @@ fun BodyResolveComponents.transformQualifiedAccessUsingSmartcastInfo(
         originalExpression = qualifiedAccessExpression
         smartcastType = intersectedTypeRef
         this.typesFromSmartCast = typesFromSmartCast
-        smartcastStability = SmartcastStability.STABLE_VALUE
+        // TODO: differentiate capture local variable
+        this.smartcastStability = stability.impliedSmartcastStability ?: SmartcastStability.STABLE_VALUE
     }
 }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzer.kt

@@ -162,7 +162,7 @@ abstract class FirDataFlowAnalyzer<FLOW : Flow>(
 
     // ----------------------------------- Requests -----------------------------------
 
-    fun getTypeUsingSmartcastInfo(qualifiedAccessExpression: FirQualifiedAccessExpression): MutableList<ConeKotlinType>? {
+    fun getTypeUsingSmartcastInfo(qualifiedAccessExpression: FirQualifiedAccessExpression): Pair<PropertyStability, MutableList<ConeKotlinType>>? {
         /*
          * DataFlowAnalyzer holds variables only for declarations that have some smartcast (or can have)
          * If there is no useful information there is no data flow variable also
@@ -170,13 +170,14 @@ abstract class FirDataFlowAnalyzer<FLOW : Flow>(
         val symbol: AbstractFirBasedSymbol<*> = qualifiedAccessExpression.symbol ?: return null
         val flow = graphBuilder.lastNode.flow
         var variable = variableStorage.getRealVariableWithoutUnwrappingAlias(symbol, qualifiedAccessExpression, flow) ?: return null
+        val stability = variable.stability
         val result = mutableListOf<ConeKotlinType>()
         flow.directAliasMap[variable]?.let {
             result.addIfNotNull(it.originalType)
             variable = it.variable
         }
         flow.getTypeStatement(variable)?.exactType?.let { result += it }
-        return result.takeIf { it.isNotEmpty() }
+        return result.takeIf { it.isNotEmpty() }?.let { stability to it }
     }
 
     fun returnExpressionsOfAnonymousFunction(function: FirAnonymousFunction): Collection<FirStatement> {
@@ -1009,7 +1010,12 @@ abstract class FirDataFlowAnalyzer<FLOW : Flow>(
         assignment: FirVariableAssignment?
     ) {
         val flow = node.flow
-        val propertyVariable = variableStorage.getOrCreateRealVariableWithoutUnwrappingAlias(flow, property.symbol, assignment ?: property)
+        val propertyVariable = variableStorage.getOrCreateRealVariableWithoutUnwrappingAlias(
+            flow,
+            property.symbol,
+            assignment ?: property,
+            if (property.isVal) PropertyStability.STABLE_VALUE else PropertyStability.LOCAL_VAR
+        )
         val isAssignment = assignment != null
         if (isAssignment) {
             logicSystem.removeLocalVariableAlias(flow, propertyVariable)
@@ -1017,13 +1023,21 @@ abstract class FirDataFlowAnalyzer<FLOW : Flow>(
             logicSystem.recordNewAssignment(flow, propertyVariable, context.newAssignmentIndex())
         }
 
-        variableStorage.getOrCreateRealVariable(flow, initializer.symbol, initializer)?.let { initializerVariable ->
-            logicSystem.addLocalVariableAlias(
-                flow, propertyVariable,
-                RealVariableAndType(initializerVariable, initializer.coneType)
-            )
-            // node.flow.addImplication((propertyVariable notEq null) implies (initializerVariable notEq null))
-        }
+        variableStorage.getOrCreateRealVariable(flow, initializer.symbol, initializer)
+            ?.let { initializerVariable ->
+                // TODO: handle capture variable
+                if ((initializerVariable.stability == PropertyStability.STABLE_VALUE || initializerVariable.stability == PropertyStability.LOCAL_VAR) &&
+                    (propertyVariable.stability == PropertyStability.STABLE_VALUE || propertyVariable.stability == PropertyStability.LOCAL_VAR)
+                ) {
+                    logicSystem.addLocalVariableAlias(
+                        flow, propertyVariable,
+                        RealVariableAndType(initializerVariable, initializer.coneType)
+                    )
+                    // node.flow.addImplication((propertyVariable notEq null) implies (initializerVariable notEq null))
+                } else {
+                    logicSystem.replaceVariableFromConditionInStatements(flow, initializerVariable, propertyVariable)
+                }
+            }
 
         variableStorage.getSyntheticVariable(initializer)?.let { initializerVariable ->
             /*

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/VariableStorage.kt

@@ -8,7 +8,9 @@ package org.jetbrains.kotlin.fir.resolve.dfa
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.FirAnonymousObject
 import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertyAccessor
 import org.jetbrains.kotlin.fir.declarations.modality
 import org.jetbrains.kotlin.fir.expressions.*
@@ -34,14 +36,24 @@ class VariableStorage(private val session: FirSession) {
 
     fun clear(): VariableStorage = VariableStorage(session)
 
-    fun getOrCreateRealVariableWithoutUnwrappingAlias(flow: Flow, symbol: AbstractFirBasedSymbol<*>, fir: FirElement): RealVariable {
+    fun getOrCreateRealVariableWithoutUnwrappingAlias(
+        flow: Flow,
+        symbol: AbstractFirBasedSymbol<*>,
+        fir: FirElement,
+        stability: PropertyStability
+    ): RealVariable {
         val realFir = fir.unwrapElement()
         val identifier = getIdentifierBySymbol(flow, symbol, realFir)
-        return _realVariables.getOrPut(identifier) { createRealVariableInternal(flow, identifier, realFir) }
+        return _realVariables.getOrPut(identifier) { createRealVariableInternal(flow, identifier, realFir, stability) }
     }
 
-    private fun getOrCreateRealVariable(flow: Flow, symbol: AbstractFirBasedSymbol<*>, fir: FirElement): RealVariable {
-        val variable = getOrCreateRealVariableWithoutUnwrappingAlias(flow, symbol, fir)
+    private fun getOrCreateRealVariable(
+        flow: Flow,
+        symbol: AbstractFirBasedSymbol<*>,
+        fir: FirElement,
+        stability: PropertyStability
+    ): RealVariable {
+        val variable = getOrCreateRealVariableWithoutUnwrappingAlias(flow, symbol, fir, stability)
         return flow.directAliasMap[variable]?.variable ?: variable
     }
 
@@ -69,7 +81,12 @@ class VariableStorage(private val session: FirSession) {
     /**
      * [originalFir] used for extracting expression under <when_subject> and extracting receiver
      */
-    private fun createRealVariableInternal(flow: Flow, identifier: Identifier, originalFir: FirElement): RealVariable {
+    private fun createRealVariableInternal(
+        flow: Flow,
+        identifier: Identifier,
+        originalFir: FirElement,
+        stability: PropertyStability
+    ): RealVariable {
         val receiver: FirExpression?
         val isThisReference: Boolean
         val expression: FirQualifiedAccess? = when (originalFir) {
@@ -88,12 +105,12 @@ class VariableStorage(private val session: FirSession) {
         }
 
         val receiverVariable = receiver?.let { getOrCreateVariable(flow, it) }
-        return RealVariable(identifier, isThisReference, receiverVariable, counter++)
+        return RealVariable(identifier, isThisReference, receiverVariable, counter++, stability)
     }
 
     @JvmName("getOrCreateRealVariableOrNull")
     fun getOrCreateRealVariable(flow: Flow, symbol: AbstractFirBasedSymbol<*>?, fir: FirElement): RealVariable? =
-        symbol.takeIf { it.isStable(fir) }?.let { getOrCreateRealVariable(flow, it, fir) }
+        symbol.getStability(fir)?.let { getOrCreateRealVariable(flow, symbol!!, fir, it) }
 
     fun createSyntheticVariable(fir: FirElement): SyntheticVariable =
         SyntheticVariable(fir, counter++).also { syntheticVariables[fir] = it }
@@ -101,8 +118,9 @@ class VariableStorage(private val session: FirSession) {
     fun getOrCreateVariable(flow: Flow, fir: FirElement): DataFlowVariable {
         val realFir = fir.unwrapElement()
         val symbol = realFir.symbol
-        return if (symbol.isStable(realFir)) {
-            getOrCreateRealVariable(flow, symbol!!, realFir)
+        val stability = symbol.getStability(realFir)
+        return if (stability != null) {
+            getOrCreateRealVariable(flow, symbol!!, realFir, stability)
         } else {
             syntheticVariables[realFir] ?: createSyntheticVariable(realFir)
         }
@@ -110,7 +128,7 @@ class VariableStorage(private val session: FirSession) {
 
     fun getRealVariableWithoutUnwrappingAlias(symbol: AbstractFirBasedSymbol<*>?, fir: FirElement, flow: Flow): RealVariable? {
         val realFir = fir.unwrapElement()
-        return symbol.takeIf { it.isStable(realFir) }?.let {
+        return symbol.takeIf { it.getStability(realFir) != null }?.let {
             _realVariables[getIdentifierBySymbol(flow, it, realFir.unwrapElement())]
         }
     }
@@ -126,7 +144,8 @@ class VariableStorage(private val session: FirSession) {
     fun getVariable(fir: FirElement, flow: Flow): DataFlowVariable? {
         val realFir = fir.unwrapElement()
         val symbol = realFir.symbol
-        return if (symbol.isStable(fir)) {
+        val stability = symbol.getStability(fir)
+        return if (stability != null) {
             getRealVariable(symbol, realFir, flow)
         } else {
             getSyntheticVariable(fir)
@@ -143,39 +162,40 @@ class VariableStorage(private val session: FirSession) {
     }
 
     @OptIn(ExperimentalContracts::class)
-    fun AbstractFirBasedSymbol<*>?.isStable(originalFir: FirElement): Boolean {
+    fun AbstractFirBasedSymbol<*>?.getStability(originalFir: FirElement): PropertyStability? {
         contract {
-            returns(true) implies(this@isStable != null)
+            returnsNotNull() implies (this@getStability != null)
         }
         when (this) {
-            is FirAnonymousObjectSymbol -> return false
+            is FirAnonymousObjectSymbol -> return null
             is FirFunctionSymbol<*>,
             is FirClassSymbol<*>,
-            is FirBackingFieldSymbol -> return true
-            null -> return false
+            is FirBackingFieldSymbol -> return PropertyStability.STABLE_VALUE
+            null -> return null
         }
-        if (originalFir is FirThisReceiverExpression) return true
-        if (this !is FirVariableSymbol<*>) return false
+        if (originalFir is FirThisReceiverExpression) return PropertyStability.STABLE_VALUE
+        if (this !is FirVariableSymbol<*>) return null
 
-        val property = this.fir as? FirProperty ?: return true
+        val property = this.fir as? FirProperty ?: return PropertyStability.STABLE_VALUE
 
         return when {
-            property.isLocal -> true
-            property.isVar -> false
-            property.receiverTypeRef != null -> false
-            property.getter.let { it != null && it !is FirDefaultPropertyAccessor } -> false
+            property.delegate != null -> PropertyStability.DELEGATED_PROPERTY
+            property.isLocal -> if (property.isVal) PropertyStability.STABLE_VALUE else PropertyStability.LOCAL_VAR
+            property.isVar -> PropertyStability.MUTABLE_PROPERTY
+            property.receiverTypeRef != null -> PropertyStability.PROPERTY_WITH_GETTER
+            property.getter.let { it != null && it !is FirDefaultPropertyAccessor } -> PropertyStability.PROPERTY_WITH_GETTER
+            property.moduleData.session != session -> PropertyStability.ALIEN_PUBLIC_PROPERTY
             property.modality != Modality.FINAL -> {
-                val dispatchReceiver = (originalFir.unwrapElement() as? FirQualifiedAccess)?.dispatchReceiver ?: return false
-                val receiverType = dispatchReceiver.typeRef.coneTypeSafe<ConeClassLikeType>()?.fullyExpandedType(session) ?: return false
-                val receiverSymbol = receiverType.lookupTag.toSymbol(session) ?: return false
+                val dispatchReceiver = (originalFir.unwrapElement() as? FirQualifiedAccess)?.dispatchReceiver ?: return null
+                val receiverType = dispatchReceiver.typeRef.coneTypeSafe<ConeClassLikeType>()?.fullyExpandedType(session) ?: return null
+                val receiverSymbol = receiverType.lookupTag.toSymbol(session) ?: return null
                 when (val receiverFir = receiverSymbol.fir) {
-                    is org.jetbrains.kotlin.fir.declarations.FirAnonymousObject -> true
-                    is org.jetbrains.kotlin.fir.declarations.FirRegularClass -> receiverFir.modality == Modality.FINAL
+                    is FirAnonymousObject -> PropertyStability.STABLE_VALUE
+                    is FirRegularClass -> if (receiverFir.modality == Modality.FINAL) PropertyStability.STABLE_VALUE else PropertyStability.PROPERTY_WITH_GETTER
                     else -> throw IllegalStateException("Should not be here: $receiverFir")
                 }
-
             }
-            else -> true
+            else -> PropertyStability.STABLE_VALUE
         }
     }
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/model.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.ConeClassErrorType
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.types.SmartcastStability
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.contract
 
@@ -33,11 +34,37 @@ sealed class DataFlowVariable(private val variableIndexForDebug: Int) {
     }
 }
 
+enum class PropertyStability(val impliedSmartcastStability: SmartcastStability?) {
+    // Immutable and no custom getter or local.
+    // Smartcast is definitely safe regardless of usage.
+    STABLE_VALUE(SmartcastStability.STABLE_VALUE),
+
+    // Open or custom getter.
+    // Smartcast is always unsafe regardless of usage.
+    PROPERTY_WITH_GETTER(SmartcastStability.PROPERTY_WITH_GETTER),
+
+    // Protected / public member value from another module.
+    // Smartcast is always unsafe regardless of usage.
+    ALIEN_PUBLIC_PROPERTY(SmartcastStability.ALIEN_PUBLIC_PROPERTY),
+
+    // Smartcast may or may not be safe, depending on whether there are concurrent writes to this local variable.
+    LOCAL_VAR(null),
+
+    // Mutable member property of a class or object.
+    // Smartcast is always unsafe regardless of usage.
+    MUTABLE_PROPERTY(SmartcastStability.MUTABLE_PROPERTY),
+
+    // Delegated property of a class or object.
+    // Smartcast is always unsafe regardless of usage.
+    DELEGATED_PROPERTY(SmartcastStability.DELEGATED_PROPERTY),
+}
+
 class RealVariable(
     val identifier: Identifier,
     val isThisReference: Boolean,
     val explicitReceiverVariable: DataFlowVariable?,
-    variableIndexForDebug: Int
+    variableIndexForDebug: Int,
+    val stability: PropertyStability,
 ) : DataFlowVariable(variableIndexForDebug) {
     override fun equals(other: Any?): Boolean {
         return this === other

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/NodeConfigurator.kt

@@ -467,6 +467,8 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
             +field("originalExpression", qualifiedAccessExpression)
             +field("typesFromSmartCast", "Collection<ConeKotlinType>", null, customType = coneKotlinTypeType)
             +field("originalType", typeRef)
+            +field("smartcastType", typeRef)
+            +smartcastStability
         }
 
         safeCallExpression.configure {

compiler/testData/diagnostics/tests/inference/nestedCalls/makeNullableIfSafeCall.fir.kt

@@ -14,13 +14,13 @@ fun test(u: A?, x: A?, y: A?, z: A?, w: A, v: A?) {
     u!!.b<!UNNECESSARY_SAFE_CALL!>?.<!>foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
     x?.b!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
     // x?.b is not null
-    x!!.b<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
+    x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.b<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
 
     y?.nb?.foo()!!
     y!!.nb?.foo()!!
     z?.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
     // z?.nb is not null
-    z!!.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
+    z<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.nb!!.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
 
     w.b<!UNNECESSARY_SAFE_CALL!>?.<!>foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
     w.b<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.foo()<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>

compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModule.fir.kt

@@ -17,7 +17,7 @@ import a.X
 public fun X.gav(): Int {
     if (x != null)
         // Smart cast is not possible if definition is in another module
-        return x.length
+        return x<!UNSAFE_CALL!>.<!>length
     else
         return 0
 }
@@ -29,7 +29,7 @@ package a
 public fun X.gav(): Int {
     if (x != null)
         // Even if it's in the same package
-        return x.length
+        return x<!UNSAFE_CALL!>.<!>length
     else
         return 0
 }

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/53.fir.kt

@@ -33,7 +33,7 @@ fun case_3(x: Int) = ""
 fun case_3(x: Int?) = 10
 fun case_3() {
     if (case_3_prop != null) {
-        val z = case_3(<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>case_3_prop<!>)
+        val z = case_3(<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int?")!>case_3_prop<!>)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>z<!>
     }
 }
@@ -89,7 +89,7 @@ fun case_7(x: Int) = ""
 fun case_7(x: Int?) = 10
 fun case_7() {
     if (case_7_prop != null) {
-        val z = case_7(<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>case_7_prop<!>)
+        val z = case_7(<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int? & kotlin.Int?")!>case_7_prop<!>)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>z<!>
     }
 }