FIR: Rework receivers processing in resolution

- Put extensionReceiver to candidate even if it's explicit (for sake of clarity)
- Split CheckReceiver (dispatch part should only check nullability)

compiler/fir/analysis-tests/testData/resolveWithStdlib/plusAssignNullable.kt

@@ -0,0 +1,16 @@
+interface A {
+    val list: List<String>
+}
+
+interface B {
+    val list: MutableList<String>
+}
+
+fun B.foo(a: A?) {
+    list.plusAssign(mutableListOf(""))
+    with(a) {
+        list.plusAssign(mutableListOf(""))
+        list += mutableListOf("")
+    }
+}
+

compiler/fir/analysis-tests/testData/resolveWithStdlib/plusAssignNullable.txt

@@ -0,0 +1,19 @@
+FILE: plusAssignNullable.kt
+    public abstract interface A : R|kotlin/Any| {
+        public abstract val list: R|kotlin/collections/List<kotlin/String>|
+            public get(): R|kotlin/collections/List<kotlin/String>|
+
+    }
+    public abstract interface B : R|kotlin/Any| {
+        public abstract val list: R|kotlin/collections/MutableList<kotlin/String>|
+            public get(): R|kotlin/collections/MutableList<kotlin/String>|
+
+    }
+    public final fun R|B|.foo(a: R|A?|): R|kotlin/Unit| {
+        this@R|/foo|.R|/B.list|.R|kotlin/collections/plusAssign|<R|kotlin/String|>(R|kotlin/collections/mutableListOf|<R|kotlin/String|>(vararg(String())))
+        R|kotlin/with|<R|A?|, R|kotlin/Unit|>(R|<local>/a|, <L> = with@fun R|A?|.<anonymous>(): R|kotlin/Unit| <kind=EXACTLY_ONCE>  {
+            this@R|/foo|.R|/B.list|.R|kotlin/collections/plusAssign|<R|kotlin/String|>(R|kotlin/collections/mutableListOf|<R|kotlin/String|>(vararg(String())))
+            this@R|/foo|.R|/B.list|.R|kotlin/collections/plusAssign|<R|kotlin/String|>(R|kotlin/collections/mutableListOf|<R|kotlin/String|>(vararg(String())))
+        }
+        )
+    }

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirDiagnosticsWithStdlibTestGenerated.java

@@ -208,6 +208,11 @@ public class FirDiagnosticsWithStdlibTestGenerated extends AbstractFirDiagnostic
         runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/nullableTypeParameter.kt");
     }
 
+    @TestMetadata("plusAssignNullable.kt")
+    public void testPlusAssignNullable() throws Exception {
+        runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/plusAssignNullable.kt");
+    }
+
     @TestMetadata("problems.kt")
     public void testProblems() throws Exception {
         runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/problems.kt");

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CallKind.kt

@@ -12,8 +12,8 @@ sealed class CallKind(vararg resolutionSequence: ResolutionStage) {
         CheckExplicitReceiverConsistency,
         NoTypeArguments,
         CreateFreshTypeVariableSubstitutorStage,
-        CheckReceivers.Dispatch,
+        CheckDispatchReceiver,
-        CheckReceivers.Extension,
+        CheckExtensionReceiver,
         CheckLowPriorityInOverloadResolution,
         PostponedVariablesInitializerResolutionStage
     )
@@ -33,8 +33,8 @@ sealed class CallKind(vararg resolutionSequence: ResolutionStage) {
         CheckExplicitReceiverConsistency,
         MapTypeArguments,
         CreateFreshTypeVariableSubstitutorStage,
-        CheckReceivers.Dispatch,
+        CheckDispatchReceiver,
-        CheckReceivers.Extension,
+        CheckExtensionReceiver,
         CheckArguments,
         EagerResolveOfCallableReferences,
         CheckLowPriorityInOverloadResolution,
@@ -47,8 +47,8 @@ sealed class CallKind(vararg resolutionSequence: ResolutionStage) {
         CheckExplicitReceiverConsistency,
         MapTypeArguments,
         CreateFreshTypeVariableSubstitutorStage,
-        CheckReceivers.Dispatch,
+        CheckDispatchReceiver,
-        CheckReceivers.Extension,
+        CheckExtensionReceiver,
         CheckArguments,
         EagerResolveOfCallableReferences
     )
@@ -58,8 +58,8 @@ sealed class CallKind(vararg resolutionSequence: ResolutionStage) {
         DiscriminateSynthetics,
         NoTypeArguments,
         CreateFreshTypeVariableSubstitutorStage,
-        CheckReceivers.Dispatch,
+        CheckDispatchReceiver,
-        CheckReceivers.Extension,
+        CheckExtensionReceiver,
         CheckCallableReferenceExpectedType,
         CheckLowPriorityInOverloadResolution
     )
@@ -102,8 +102,8 @@ class ResolutionSequenceBuilder(
             if (checkExplicitReceiverConsistency) add(CheckExplicitReceiverConsistency)
             if (mapTypeArguments) add(MapTypeArguments) else add(NoTypeArguments)
             if (checkArguments || checkDispatchReceiver || checkExtensionReceiver) add(CreateFreshTypeVariableSubstitutorStage)
-            if (checkDispatchReceiver) add(CheckReceivers.Dispatch)
+            if (checkDispatchReceiver) add(CheckDispatchReceiver)
-            if (checkExtensionReceiver) add(CheckReceivers.Extension)
+            if (checkExtensionReceiver) add(CheckExtensionReceiver)
             if (checkArguments) add(CheckArguments)
             if (resolveCallableReferenceArguments) add(EagerResolveOfCallableReferences)
             if (checkLowPriorityInOverloadResolution) add(CheckLowPriorityInOverloadResolution)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Candidate.kt

@@ -15,7 +15,6 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildArgumentList
 import org.jetbrains.kotlin.fir.expressions.impl.FirExpressionStub
 import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
-import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.DoubleColonLHS
 import org.jetbrains.kotlin.fir.resolve.inference.InferenceComponents
 import org.jetbrains.kotlin.fir.resolve.inference.PostponedResolvedAtom
@@ -81,7 +80,7 @@ data class CallInfo(
 class Candidate(
     val symbol: AbstractFirBasedSymbol<*>,
     val dispatchReceiverValue: ReceiverValue?,
-    val implicitExtensionReceiverValue: ImplicitReceiverValue<*>?,
+    val extensionReceiverValue: ReceiverValue?,
     val explicitReceiverKind: ExplicitReceiverKind,
     val constraintSystemFactory: InferenceComponents.ConstraintSystemFactory,
     private val baseSystem: ConstraintStorage,
@@ -128,18 +127,11 @@ class Candidate(
 
     var passedStages: Int = 0
 
-    fun dispatchReceiverExpression(): FirExpression = when (explicitReceiverKind) {
+    fun dispatchReceiverExpression(): FirExpression =
-        ExplicitReceiverKind.DISPATCH_RECEIVER, ExplicitReceiverKind.BOTH_RECEIVERS ->
+        dispatchReceiverValue?.receiverExpression?.takeIf { it !is FirExpressionStub } ?: FirNoReceiverExpression
-            callInfo.explicitReceiver?.takeIf { it !is FirExpressionStub } ?: FirNoReceiverExpression
-        else -> dispatchReceiverValue?.receiverExpression ?: FirNoReceiverExpression
-    }
 
-    fun extensionReceiverExpression(): FirExpression = when (explicitReceiverKind) {
+    fun extensionReceiverExpression(): FirExpression =
-        ExplicitReceiverKind.EXTENSION_RECEIVER, ExplicitReceiverKind.BOTH_RECEIVERS ->
+        extensionReceiverValue?.receiverExpression?.takeIf { it !is FirExpressionStub } ?: FirNoReceiverExpression
-            callInfo.explicitReceiver?.takeIf { it !is FirExpressionStub } ?: FirNoReceiverExpression
-        else ->
-            implicitExtensionReceiverValue?.receiverExpression ?: FirNoReceiverExpression
-    }
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CandidateFactory.kt

@@ -52,11 +52,11 @@ class CandidateFactory private constructor(
         explicitReceiverKind: ExplicitReceiverKind,
         scope: FirScope?,
         dispatchReceiverValue: ReceiverValue? = null,
-        implicitExtensionReceiverValue: ImplicitReceiverValue<*>? = null,
+        extensionReceiverValue: ReceiverValue? = null,
         builtInExtensionFunctionReceiverValue: ReceiverValue? = null
     ): Candidate {
         return Candidate(
-            symbol, dispatchReceiverValue, implicitExtensionReceiverValue,
+            symbol, dispatchReceiverValue, extensionReceiverValue,
             explicitReceiverKind, context.inferenceComponents.constraintSystemFactory, baseSystem,
             builtInExtensionFunctionReceiverValue?.receiverExpression?.let {
                 callInfo.withReceiverAsArgument(it)
@@ -78,7 +78,7 @@ class CandidateFactory private constructor(
         return Candidate(
             symbol,
             dispatchReceiverValue = null,
-            implicitExtensionReceiverValue = null,
+            extensionReceiverValue = null,
             explicitReceiverKind = ExplicitReceiverKind.NO_EXPLICIT_RECEIVER,
             context.inferenceComponents.constraintSystemFactory,
             baseSystem,

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt

@@ -22,8 +22,11 @@ import org.jetbrains.kotlin.fir.scopes.FirTypeScope
 import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
-import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.fir.types.ConeKotlinErrorType
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
+import org.jetbrains.kotlin.fir.types.coneType
+import org.jetbrains.kotlin.fir.types.coneTypeSafe
 
 interface Receiver
 
@@ -51,7 +54,7 @@ abstract class AbstractExplicitReceiverValue<E : FirExpression> : AbstractExplic
         get() = explicitReceiver
 }
 
-internal class ExpressionReceiverValue(
+class ExpressionReceiverValue(
     override val explicitReceiver: FirExpression
 ) : AbstractExplicitReceiverValue<FirExpression>(), ReceiverValue
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionStages.kt

@@ -22,8 +22,8 @@ import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind.*
+import org.jetbrains.kotlin.types.AbstractNullabilityChecker
 
 abstract class ResolutionStage {
     abstract suspend fun check(candidate: Candidate, callInfo: CallInfo, sink: CheckerSink, context: ResolutionContext)
@@ -57,52 +57,44 @@ internal object CheckExplicitReceiverConsistency : ResolutionStage() {
     }
 }
 
-internal sealed class CheckReceivers : ResolutionStage() {
+object CheckExtensionReceiver : ResolutionStage() {
-    object Dispatch : CheckReceivers() {
-        override fun ExplicitReceiverKind.shouldBeCheckedAgainstImplicit(): Boolean {
-            return this == EXTENSION_RECEIVER // For NO_EXPLICIT_RECEIVER we can check extension receiver only
-        }
-
-        override fun ExplicitReceiverKind.shouldBeCheckedAgainstExplicit(): Boolean {
-            return this == DISPATCH_RECEIVER || this == BOTH_RECEIVERS
-        }
-
-        override fun Candidate.getReceiverType(context: ResolutionContext): ConeKotlinType? {
-            return dispatchReceiverValue?.type
-        }
-    }
-
-    object Extension : CheckReceivers() {
-        override fun ExplicitReceiverKind.shouldBeCheckedAgainstImplicit(): Boolean {
-            return this == DISPATCH_RECEIVER || this == NO_EXPLICIT_RECEIVER
-        }
-
-        override fun ExplicitReceiverKind.shouldBeCheckedAgainstExplicit(): Boolean {
-            return this == EXTENSION_RECEIVER || this == BOTH_RECEIVERS
-        }
-
-        override fun Candidate.getReceiverType(context: ResolutionContext): ConeKotlinType? {
-            val callableSymbol = symbol as? FirCallableSymbol<*> ?: return null
-            val callable = callableSymbol.fir
-            val receiverType = callable.receiverTypeRef?.coneType
-            if (receiverType != null) return receiverType
-            val returnTypeRef = callable.returnTypeRef as? FirResolvedTypeRef ?: return null
-            if (!returnTypeRef.type.isExtensionFunctionType(context.session)) return null
-            return (returnTypeRef.type.typeArguments.firstOrNull() as? ConeKotlinTypeProjection)?.type
-        }
-    }
-
-    abstract fun Candidate.getReceiverType(context: ResolutionContext): ConeKotlinType?
-
-    abstract fun ExplicitReceiverKind.shouldBeCheckedAgainstExplicit(): Boolean
-
-    abstract fun ExplicitReceiverKind.shouldBeCheckedAgainstImplicit(): Boolean
-
     override suspend fun check(candidate: Candidate, callInfo: CallInfo, sink: CheckerSink, context: ResolutionContext) {
-        val expectedReceiverType = candidate.getReceiverType(context)
+        val expectedReceiverType = candidate.getReceiverType(context) ?: return
-        val explicitReceiverExpression = callInfo.explicitReceiver
-        val explicitReceiverKind = candidate.explicitReceiverKind
 
+        val argumentExtensionReceiverValue = candidate.extensionReceiverValue ?: return
+        val expectedType = candidate.substitutor.substituteOrSelf(expectedReceiverType.type)
+        val argumentType = captureFromTypeParameterUpperBoundIfNeeded(
+            argumentType = argumentExtensionReceiverValue.type,
+            expectedType = expectedType,
+            session = context.session
+        )
+        candidate.resolvePlainArgumentType(
+            candidate.csBuilder,
+            argumentType = argumentType,
+            expectedType = expectedType,
+            sink = sink,
+            context = context,
+            isReceiver = true,
+            isDispatch = false,
+        )
+
+        sink.yieldIfNeed()
+    }
+
+    private fun Candidate.getReceiverType(context: ResolutionContext): ConeKotlinType? {
+        val callableSymbol = symbol as? FirCallableSymbol<*> ?: return null
+        val callable = callableSymbol.fir
+        val receiverType = callable.receiverTypeRef?.coneType
+        if (receiverType != null) return receiverType
+        val returnTypeRef = callable.returnTypeRef as? FirResolvedTypeRef ?: return null
+        if (!returnTypeRef.type.isExtensionFunctionType(context.session)) return null
+        return (returnTypeRef.type.typeArguments.firstOrNull() as? ConeKotlinTypeProjection)?.type
+    }
+}
+
+object CheckDispatchReceiver : ResolutionStage() {
+    override suspend fun check(candidate: Candidate, callInfo: CallInfo, sink: CheckerSink, context: ResolutionContext) {
+        val explicitReceiverExpression = callInfo.explicitReceiver
         if (explicitReceiverExpression.isSuperCall()) {
             val status = candidate.symbol.fir as? FirMemberDeclaration
             if (status?.modality == Modality.ABSTRACT) {
@@ -110,49 +102,17 @@ internal sealed class CheckReceivers : ResolutionStage() {
             }
         }
 
-        if (expectedReceiverType != null) {
+        val dispatchReceiverValueType = candidate.dispatchReceiverValue?.type ?: return
-            if (explicitReceiverExpression != null &&
+
-                explicitReceiverKind.shouldBeCheckedAgainstExplicit() &&
+        if (!AbstractNullabilityChecker.isSubtypeOfAny(context.session.typeContext, dispatchReceiverValueType)) {
-                !explicitReceiverExpression.isSuperReferenceExpression()
+            sink.yieldDiagnostic(InapplicableWrongReceiver)
-            ) {
-                candidate.resolvePlainExpressionArgument(
-                    candidate.csBuilder,
-                    argument = explicitReceiverExpression,
-                    expectedType = candidate.substitutor.substituteOrSelf(expectedReceiverType),
-                    sink = sink,
-                    context = context,
-                    isReceiver = true,
-                    isDispatch = this is Dispatch
-                )
-                sink.yieldIfNeed()
-            } else {
-                val argumentExtensionReceiverValue = candidate.implicitExtensionReceiverValue
-                if (argumentExtensionReceiverValue != null && explicitReceiverKind.shouldBeCheckedAgainstImplicit()) {
-                    val expectedType = candidate.substitutor.substituteOrSelf(expectedReceiverType.type)
-                    val argumentType = captureFromTypeParameterUpperBoundIfNeeded(
-                        argumentType = argumentExtensionReceiverValue.type,
-                        expectedType = expectedType,
-                        session = context.session
-                    )
-                    candidate.resolvePlainArgumentType(
-                        candidate.csBuilder,
-                        argumentType = argumentType,
-                        expectedType = expectedType,
-                        sink = sink,
-                        context = context,
-                        isReceiver = true,
-                        isDispatch = this is Dispatch
-                    )
-                    sink.yieldIfNeed()
-                }
-            }
         }
     }
+}
 
-    private fun FirExpression?.isSuperCall(): Boolean {
+private fun FirExpression?.isSuperCall(): Boolean {
-        if (this !is FirQualifiedAccessExpression) return false
+    if (this !is FirQualifiedAccessExpression) return false
-        return calleeReference is FirSuperReference
+    return calleeReference is FirSuperReference
-    }
 }
 
 private fun FirExpression.isSuperReferenceExpression(): Boolean {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolver.kt

@@ -65,9 +65,8 @@ class FirTowerResolver(
             }
             else -> {
                 if (receiver is FirQualifiedAccessExpression) {
-                    val calleeReference = receiver.calleeReference
+                    if (receiver.calleeReference is FirSuperReference) {
-                    if (calleeReference is FirSuperReference) {
+                        manager.enqueueResolverTask { mainTask.runResolverForSuperReceiver(info, receiver) }
-                        manager.enqueueResolverTask { mainTask.runResolverForSuperReceiver(info, receiver.typeRef) }
                         return
                     }
                 }
@@ -108,7 +107,7 @@ class FirTowerResolver(
                     ExplicitReceiverKind.NO_EXPLICIT_RECEIVER,
                     scope,
                     dispatchReceiver,
-                    implicitExtensionReceiverValue = null,
+                    extensionReceiverValue = null,
                     builtInExtensionFunctionReceiverValue = null
                 ),
                 context

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerLevelHandler.kt

@@ -14,7 +14,10 @@ import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.typeContext
-import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.fir.types.ConeClassLikeType
+import org.jetbrains.kotlin.fir.types.ConeStarProjection
+import org.jetbrains.kotlin.fir.types.coneType
+import org.jetbrains.kotlin.fir.types.constructClassType
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitBuiltinTypeRef
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
@@ -68,19 +71,13 @@ internal class TowerLevelHandler {
             CallKind.CallableReference -> {
                 val stubReceiver = info.stubReceiver
                 if (stubReceiver != null) {
-                    val stubReceiverValue = ExpressionReceiverValue(stubReceiver)
                     val stubProcessor = TowerScopeLevelProcessor(
                         info.explicitReceiver,
-                        if (towerLevel is MemberScopeTowerLevel && towerLevel.dispatchReceiver is AbstractExplicitReceiver<*>) {
+                        explicitReceiverKind,
-                            ExplicitReceiverKind.DISPATCH_RECEIVER
-                        } else {
-                            ExplicitReceiverKind.EXTENSION_RECEIVER
-                        },
                         collector,
                         stubReceiverCandidateFactory!!, group
                     )
-                    val towerLevelWithStubReceiver = towerLevel.replaceReceiverValue(stubReceiverValue)
+                    towerLevel.processFunctionsAndProperties(info.name, stubProcessor)
-                    towerLevelWithStubReceiver.processFunctionsAndProperties(info.name, stubProcessor)
                     // NB: we don't perform this for implicit Unit
                     if (!collector.isSuccess() && info.explicitReceiver?.typeRef !is FirImplicitBuiltinTypeRef) {
                         towerLevel.processFunctionsAndProperties(info.name, processor)
@@ -147,18 +144,17 @@ private class TowerScopeLevelProcessor(
     override fun consumeCandidate(
         symbol: AbstractFirBasedSymbol<*>,
         dispatchReceiverValue: ReceiverValue?,
-        implicitExtensionReceiverValue: ImplicitReceiverValue<*>?,
+        extensionReceiverValue: ReceiverValue?,
         scope: FirScope,
         builtInExtensionFunctionReceiverValue: ReceiverValue?
     ) {
         // Check explicit extension receiver for default package members
         if (symbol is FirNamedFunctionSymbol && dispatchReceiverValue == null &&
-            (implicitExtensionReceiverValue == null) != (explicitReceiver == null) &&
+            extensionReceiverValue != null &&
             explicitReceiver !is FirResolvedQualifier &&
             symbol.callableId.packageName.startsWith(defaultPackage)
         ) {
-            val extensionReceiverType = explicitReceiver?.typeRef?.coneTypeSafe()
+            val extensionReceiverType = extensionReceiverValue.type as? ConeClassLikeType
-                ?: implicitExtensionReceiverValue?.type as? ConeClassLikeType
             if (extensionReceiverType != null) {
                 val declarationReceiverType = (symbol as? FirCallableSymbol<*>)?.fir?.receiverTypeRef?.coneType
                 if (declarationReceiverType is ConeClassLikeType) {
@@ -183,7 +179,7 @@ private class TowerScopeLevelProcessor(
                 explicitReceiverKind,
                 scope,
                 dispatchReceiverValue,
-                implicitExtensionReceiverValue,
+                extensionReceiverValue,
                 builtInExtensionFunctionReceiverValue
             ), candidateFactory.context
         )

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerLevels.kt

@@ -9,7 +9,6 @@ import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.declarations.isInner
 import org.jetbrains.kotlin.fir.dispatchReceiverClassOrNull
-import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildResolvedQualifier
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.*
@@ -21,9 +20,6 @@ import org.jetbrains.kotlin.fir.scopes.processClassifiersByName
 import org.jetbrains.kotlin.fir.symbols.AbstractFirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
-import org.jetbrains.kotlin.fir.types.ConeKotlinType
-import org.jetbrains.kotlin.fir.types.ConeNullability
-import org.jetbrains.kotlin.fir.types.withNullability
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.util.OperatorNameConventions
 
@@ -45,7 +41,7 @@ interface TowerScopeLevel {
         fun consumeCandidate(
             symbol: T,
             dispatchReceiverValue: ReceiverValue?,
-            implicitExtensionReceiverValue: ImplicitReceiverValue<*>?,
+            extensionReceiverValue: ReceiverValue?,
             scope: FirScope,
             builtInExtensionFunctionReceiverValue: ReceiverValue? = null
         )
@@ -69,7 +65,7 @@ abstract class SessionBasedTowerLevel(val session: FirSession) : TowerScopeLevel
 class MemberScopeTowerLevel(
     session: FirSession,
     private val bodyResolveComponents: BodyResolveComponents,
-    val dispatchReceiver: ReceiverValue,
+    val dispatchReceiverValue: ReceiverValue,
     private val extensionReceiver: ReceiverValue? = null,
     private val implicitExtensionInvokeMode: Boolean = false,
     private val scopeSession: ScopeSession
@@ -79,7 +75,7 @@ class MemberScopeTowerLevel(
         processScopeMembers: FirScope.(processor: (T) -> Unit) -> Unit
     ): ProcessorAction {
         var empty = true
-        val scope = dispatchReceiver.scope(session, scopeSession) ?: return ProcessorAction.NONE
+        val scope = dispatchReceiverValue.scope(session, scopeSession) ?: return ProcessorAction.NONE
         scope.processScopeMembers { candidate ->
             empty = false
             if (candidate is FirCallableSymbol<*> &&
@@ -89,24 +85,23 @@ class MemberScopeTowerLevel(
                 if ((fir as? FirConstructor)?.isInner == false) {
                     return@processScopeMembers
                 }
-                val dispatchReceiverValue = NotNullableReceiverValue(dispatchReceiver)
 
                 output.consumeCandidate(
                     candidate, dispatchReceiverValue,
-                    implicitExtensionReceiverValue = extensionReceiver as? ImplicitReceiverValue<*>,
+                    extensionReceiverValue = extensionReceiver,
                     scope
                 )
 
                 if (implicitExtensionInvokeMode) {
                     output.consumeCandidate(
                         candidate, dispatchReceiverValue,
-                        implicitExtensionReceiverValue = null,
+                        extensionReceiverValue = null,
                         scope,
                         builtInExtensionFunctionReceiverValue = this.extensionReceiver
                     )
                 }
             } else if (candidate is FirClassLikeSymbol<*>) {
-                output.consumeCandidate(candidate, null, extensionReceiver as? ImplicitReceiverValue<*>, scope)
+                output.consumeCandidate(candidate, null, extensionReceiver, scope)
             }
         }
 
@@ -114,7 +109,7 @@ class MemberScopeTowerLevel(
             val withSynthetic = FirSyntheticPropertiesScope(session, scope)
             withSynthetic.processScopeMembers { symbol ->
                 empty = false
-                output.consumeCandidate(symbol, NotNullableReceiverValue(dispatchReceiver), null, scope)
+                output.consumeCandidate(symbol, dispatchReceiverValue, null, scope)
             }
         }
         return if (empty) ProcessorAction.NONE else ProcessorAction.NEXT
@@ -221,7 +216,7 @@ class ScopeTowerLevel(
             @Suppress("UNCHECKED_CAST")
             processor.consumeCandidate(
                 unwrappedCandidate as T, dispatchReceiverValue,
-                implicitExtensionReceiverValue = extensionReceiver as? ImplicitReceiverValue<*>,
+                extensionReceiverValue = extensionReceiver,
                 scope
             )
         }
@@ -252,7 +247,7 @@ class ScopeTowerLevel(
                 empty = false
                 processor.consumeCandidate(
                     it as T, dispatchReceiverValue = null,
-                    implicitExtensionReceiverValue = null,
+                    extensionReceiverValue = null,
                     scope = scope
                 )
             }
@@ -261,13 +256,6 @@ class ScopeTowerLevel(
     }
 }
 
-class NotNullableReceiverValue(val value: ReceiverValue) : ReceiverValue {
-    override val type: ConeKotlinType
-        get() = value.type.withNullability(ConeNullability.NOT_NULL)
-    override val receiverExpression: FirExpression
-        get() = value.receiverExpression
-}
-
 private fun FirCallableSymbol<*>.hasExtensionReceiver(): Boolean {
     return fir.receiverTypeRef != null
 }

compiler/testData/codegen/box/inlineClasses/toStringOfUnboxedNullable.kt

@@ -1,6 +1,5 @@
 // !LANGUAGE: +InlineClasses
 // IGNORE_BACKEND: JVM
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_LIGHT_ANALYSIS
 inline class IC(val x: String)
 

compiler/testData/diagnostics/tests/callableReference/bound/expressionWithNullableType.fir.kt

@@ -7,8 +7,8 @@ public interface J {
 // FILE: test.kt
 
 fun f1(x: Int?): Any = <!UNRESOLVED_REFERENCE!>x::hashCode<!>
-fun <T> f2(t: T): Any = t::hashCode
+fun <T> f2(t: T): Any = <!UNRESOLVED_REFERENCE!>t::hashCode<!>
-fun <S : String?> f3(s: S): Any = s::hashCode
+fun <S : String?> f3(s: S): Any = <!UNRESOLVED_REFERENCE!>s::hashCode<!>
 fun <U : Any> f4(u: U?): Any = <!UNRESOLVED_REFERENCE!>u::hashCode<!>
 fun f5(c: List<*>): Any = <!UNRESOLVED_REFERENCE!>c[0]::hashCode<!>
 

compiler/testData/diagnostics/tests/collectionLiterals/basicCollectionLiterals.fir.kt

@@ -14,11 +14,11 @@ fun test() {
 }
 
 fun check() {
-    [1, 2] checkType { <!INAPPLICABLE_CANDIDATE!>_<!><Array<Int>>() }
+    [1, 2] <!INAPPLICABLE_CANDIDATE!>checkType<!> { <!INAPPLICABLE_CANDIDATE!>_<!><Array<Int>>() }
-    [""] checkType { <!INAPPLICABLE_CANDIDATE!>_<!><Array<String>>() }
+    [""] <!INAPPLICABLE_CANDIDATE!>checkType<!> { <!INAPPLICABLE_CANDIDATE!>_<!><Array<String>>() }
 
     val f: IntArray = [1]
-    [f] checkType { <!INAPPLICABLE_CANDIDATE!>_<!><Array<IntArray>>() }
+    [f] <!INAPPLICABLE_CANDIDATE!>checkType<!> { <!INAPPLICABLE_CANDIDATE!>_<!><Array<IntArray>>() }
 
-    [1, ""] checkType { <!INAPPLICABLE_CANDIDATE!>_<!><Array<Any>>() }
+    [1, ""] <!INAPPLICABLE_CANDIDATE!>checkType<!> { <!INAPPLICABLE_CANDIDATE!>_<!><Array<Any>>() }
-}
+}

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_3.fir.kt

@@ -11,7 +11,7 @@ fun test() {
     const val <T> a3 = 0
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit val <T> a4 = 0<!>
     val <T> a5 by Delegate<Int>()
-    val <T> a6 by Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()
+    val <T> a6 by <!INAPPLICABLE_CANDIDATE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
 }
 
 class Delegate<F> {

compiler/testData/diagnostics/tests/declarationChecks/localVariablesWithTypeParameters_1_4.fir.kt

@@ -11,7 +11,7 @@ fun test() {
     const val <T> a3 = 0
     <!INAPPLICABLE_LATEINIT_MODIFIER!>lateinit val <T> a4 = 0<!>
     val <T> a5 by Delegate<Int>()
-    val <T> a6 by Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()
+    val <T> a6 by <!INAPPLICABLE_CANDIDATE!>Delegate<<!UNRESOLVED_REFERENCE!>T<!>>()<!>
 }
 
 class Delegate<F> {

compiler/testData/diagnostics/tests/delegatedProperty/propertyDefferedType.fir.kt

@@ -5,7 +5,7 @@
 import kotlin.reflect.KProperty
 
 class B {
-    val c by <!INAPPLICABLE_CANDIDATE!>Delegate<!>(<!UNRESOLVED_REFERENCE!>ag<!>)
+    val c by <!INAPPLICABLE_CANDIDATE!><!INAPPLICABLE_CANDIDATE!>Delegate<!>(<!UNRESOLVED_REFERENCE!>ag<!>)<!>
 }
 
 class Delegate<T: Any>(val init: T) {

compiler/testData/diagnostics/tests/funInterface/funInterfaceConversionOnReceiver.fir.kt

@@ -5,5 +5,5 @@ fun interface Bar {
 operator fun Bar.plus(b: Bar): String = invoke() + b.invoke()
 
 fun box(): String {
-    return { "O" } + { "K" }
+    return { "O" } <!INAPPLICABLE_CANDIDATE!>+<!> { "K" }
 }

compiler/testData/diagnostics/tests/functionLiterals/kt6541_extensionForExtensionFunction.fir.kt

@@ -7,4 +7,4 @@ object Z {
     infix fun add(b : Foo.() -> Unit) : Z = Z
 }
 
-val t2 = Z <!INAPPLICABLE_CANDIDATE!>add<!> { } { }
+val t2 = Z <!INAPPLICABLE_CANDIDATE!>add<!> <!INAPPLICABLE_CANDIDATE!>{ } { }<!>

compiler/testData/diagnostics/tests/generics/nullability/functionalBound.fir.kt

@@ -1,6 +1,6 @@
 fun <E : String?, T : ((CharSequence) -> Unit)?> foo(x: E, y: T) {
     if (x != null) {
-        y(x)
+        <!INAPPLICABLE_CANDIDATE!>y<!>(x)
     }
 
     if (y != null) {
@@ -10,4 +10,4 @@ fun <E : String?, T : ((CharSequence) -> Unit)?> foo(x: E, y: T) {
     if (x != null && y != null) {
         y(x)
     }
-}
+}

compiler/testData/diagnostics/tests/generics/nullability/smartCastRefinedClass.fir.kt

@@ -1,6 +1,6 @@
 fun <T : Any?> foo(x: T) {
     if (x is String?) {
-        x.length
+        x.<!INAPPLICABLE_CANDIDATE!>length<!>
 
         if (x != null) {
             x.length

compiler/testData/diagnostics/tests/generics/nullability/smartCasts.fir.kt

@@ -24,7 +24,7 @@ fun <T : CharSequence?> foo(x: T) {
         x?.bar1()
     }
 
-    x.length
+    x.<!INAPPLICABLE_CANDIDATE!>length<!>
 
     if (x is String) {
         x.length

compiler/testData/diagnostics/tests/generics/nullability/smartCastsOnThis.fir.kt

@@ -23,7 +23,7 @@ fun <T : String?> T.foo() {
         this?.bar1()
     }
 
-    length
+    <!INAPPLICABLE_CANDIDATE!>length<!>
 
     if (this is String) {
         length
@@ -33,4 +33,4 @@ fun <T : String?> T.foo() {
         bar2()
         bar3()
     }
-}
+}

compiler/testData/diagnostics/tests/generics/nullability/useAsReceiver.fir.kt

@@ -7,7 +7,7 @@ fun CharSequence?.bar2() {}
 fun <T : CharSequence> T.bar3() {}
 
 fun <T : String?> foo(x: T) {
-    x.length
+    x.<!INAPPLICABLE_CANDIDATE!>length<!>
     x?.length
 
     if (1 == 1) {

compiler/testData/diagnostics/tests/generics/projectionsScope/typeParameterBounds.fir.kt

@@ -14,14 +14,14 @@ class A<T> {
 
 fun foo2(a: A<out CharSequence>, b: A<in CharSequence>) {
     a.<!INAPPLICABLE_CANDIDATE!>foo1<!>(Out<CharSequence>())
-    a.foo1<<!UPPER_BOUND_VIOLATED!>Out<CharSequence><!>>(Out())
+    a.<!INAPPLICABLE_CANDIDATE!>foo1<!><Out<CharSequence>>(Out())
 
     a.foo1(Out())
     a.foo1(Out<Nothing>())
 
     a.foo2(Inv())
     a.<!INAPPLICABLE_CANDIDATE!>foo2<!>(Inv<CharSequence>())
-    a.foo2<<!UPPER_BOUND_VIOLATED!>Inv<CharSequence><!>>(Inv())
+    a.<!INAPPLICABLE_CANDIDATE!>foo2<!><Inv<CharSequence>>(Inv())
 
     a.foo3(In())
     a.foo3(In<CharSequence>())
@@ -33,11 +33,11 @@ fun foo2(a: A<out CharSequence>, b: A<in CharSequence>) {
 
     b.foo2(Inv())
     b.<!INAPPLICABLE_CANDIDATE!>foo2<!>(Inv<CharSequence>())
-    b.foo2<<!UPPER_BOUND_VIOLATED!>Inv<CharSequence><!>>(Inv())
+    b.<!INAPPLICABLE_CANDIDATE!>foo2<!><Inv<CharSequence>>(Inv())
 
 
     b.<!INAPPLICABLE_CANDIDATE!>foo3<!>(In<CharSequence>())
-    b.foo3<<!UPPER_BOUND_VIOLATED!>In<CharSequence><!>>(In())
+    b.<!INAPPLICABLE_CANDIDATE!>foo3<!><In<CharSequence>>(In())
 
     b.foo3(In<Any?>())
     b.foo3(In())

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/ReceiverNullability.fir.kt

@@ -30,7 +30,7 @@ fun A.test2() {
 }
 
 fun A?.test3() {
-    foo() // error
+    <!INAPPLICABLE_CANDIDATE!>foo<!>() // error
     <!INAPPLICABLE_CANDIDATE!>bar<!>() // error
     buzz()
 

compiler/testData/diagnostics/tests/platformTypes/nullabilityWarnings/derefenceMember.fir.kt

@@ -32,7 +32,7 @@ fun test() {
         foo()
     }
     with(platformN) {
-        foo()
+        <!INAPPLICABLE_CANDIDATE!>foo<!>()
     }
     with(platformJ) {
         foo()

compiler/testData/diagnostics/tests/typealias/kt15734.fir.kt

@@ -15,5 +15,5 @@ val test5: List<TNString?> = TODO()
 val test6: () -> List<TNString> = TODO()
 
 fun test(x: TNString) {
-    x.hashCode()
+    x.<!INAPPLICABLE_CANDIDATE!>hashCode<!>()
 }

compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/extensionReceiver.fir.kt

@@ -17,7 +17,7 @@ fun CharSequence?.isNullOrEmpty(): Boolean {
 fun smartcastOnReceiver(s: String?) {
     with(s) {
         if (isNullOrEmpty()) {
-            length
+            <!INAPPLICABLE_CANDIDATE!>length<!>
         }
         else {
             length
@@ -32,7 +32,7 @@ fun mixedReceiver(s: String?) {
         }
     } else {
         with(s) {
-            length
+            <!INAPPLICABLE_CANDIDATE!>length<!>
         }
     }
-}
+}

compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/extensionReceiver_after.fir.kt

@@ -17,7 +17,7 @@ fun CharSequence?.isNullOrEmpty(): Boolean {
 fun smartcastOnReceiver(s: String?) {
     with(s) {
         if (isNullOrEmpty()) {
-            length
+            <!INAPPLICABLE_CANDIDATE!>length<!>
         }
         else {
             length
@@ -32,7 +32,7 @@ fun mixedReceiver(s: String?) {
         }
     } else {
         with(s) {
-            length
+            <!INAPPLICABLE_CANDIDATE!>length<!>
         }
     }
-}
+}

compiler/tests-spec/testData/diagnostics/linked/overload-resolution/building-the-overload-candidate-set-ocs/operator-call/p-1/pos/2.1.fir.kt

@@ -9,17 +9,17 @@ package testPackCase1
 
 fun case1(a: A, c: C) {
 
-    <!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved"), INAPPLICABLE_CANDIDATE!>a?.b += c<!>
+    <!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>a?.b += c<!>
-    a?.b .<!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved")!><!INAPPLICABLE_CANDIDATE!>plusAssign<!>(c)<!>
+    a?.b .<!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>plusAssign(c)<!>
 
     val x = {
-        <!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved"), INAPPLICABLE_CANDIDATE!>a?.b += c<!>
+        <!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>a?.b += c<!>
-        a?.b.<!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved")!><!INAPPLICABLE_CANDIDATE!>plusAssign<!>(c)<!>
+        a?.b.<!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>plusAssign(c)<!>
     }()
 
-    <!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved"), INAPPLICABLE_CANDIDATE!>a?.b += { c }()<!>
+    <!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>a?.b += { c }()<!>
 
-    a?.b.<!DEBUG_INFO_CALL("fqName: fqName is unknown; typeCall: unresolved")!><!INAPPLICABLE_CANDIDATE!>plusAssign<!>({ c }())<!>
+    a?.b.<!DEBUG_INFO_CALL("fqName: testPackCase1.B.plusAssign; typeCall: operator function")!>plusAssign({ c }())<!>
 }
 
 class A(val b: B)

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.fir.kt

@@ -103,8 +103,8 @@ fun case_7() {
 
 // TESTCASE NUMBER: 8
 fun case_8(x: TypealiasNullableString) {
-    if (x !== null === null && <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!> != null != null) <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!>.get(0)
+    if (x !== null === null && <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!> != null != null) <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!>.<!INAPPLICABLE_CANDIDATE!>get<!>(0)
-    if (x !== null != null && <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!> != null === null) <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!>.get(0)
+    if (x !== null != null && <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!> != null === null) <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableString")!>x<!>.<!INAPPLICABLE_CANDIDATE!>get<!>(0)
 }
 
 // TESTCASE NUMBER: 9

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/23.fir.kt

@@ -20,7 +20,7 @@ inline fun <reified T, reified K> case_1(x: T) {
 inline fun <reified T, reified K> case_2(x: T) {
     x as K
     <!DEBUG_INFO_EXPRESSION_TYPE("K & T & T")!>x<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("K & T & T")!>x<!>.equals(x)
+    <!DEBUG_INFO_EXPRESSION_TYPE("K & T & T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(x)
 }
 
 /*
@@ -49,7 +49,7 @@ inline fun <reified T, reified K> case_4(x: T?) {
 inline fun <reified T, reified K> case_5(x: T) {
     if (x is K?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("K? & T & T")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("K? & T & T")!>x<!>.equals(x)
+        <!DEBUG_INFO_EXPRESSION_TYPE("K? & T & T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(x)
     }
 }
 

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/29.fir.kt

@@ -22,8 +22,8 @@ fun case_2(a: Any?) {
         }
     })()
 
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any?")!>a<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>a<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any?")!>a<!>.equals(10)
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>a<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(10)
 }
 
 // TESTCASE NUMBER: 3

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/42.fir.kt

@@ -75,7 +75,7 @@ fun <T> case_6(x: T) {
 fun <T> case_7(x: T) {
     if (x is Int? || x is Float?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>.toByte()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>toByte<!>()
     }
 }
 
@@ -86,7 +86,7 @@ fun <T> case_7(x: T) {
 inline fun <reified T> case_8(x: T) {
     if (x is Int? || x is Float?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>.toByte()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & T & T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>toByte<!>()
     }
 }
 

compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/9.fir.kt

@@ -8,7 +8,7 @@ fun <T, K> case_1(x: T?, y: K?) {
     y as K
     val z = <!DEBUG_INFO_EXPRESSION_TYPE("T & T?")!>x<!> ?: <!DEBUG_INFO_EXPRESSION_TYPE("K & K?")!>y<!>
 
-    <!DEBUG_INFO_EXPRESSION_TYPE("T & T?")!>x<!>.equals(10)
+    <!DEBUG_INFO_EXPRESSION_TYPE("T & T?")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(10)
     <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>z<!>
     <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>z<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(10)
 }
@@ -18,5 +18,5 @@ inline fun <reified T: Any, reified K: T?> case_2(y: K?) {
     y as K
 
     <!DEBUG_INFO_EXPRESSION_TYPE("K & K?")!>y<!>
-    <!DEBUG_INFO_EXPRESSION_TYPE("K & K?")!>y<!>.equals(10)
+    <!DEBUG_INFO_EXPRESSION_TYPE("K & K?")!>y<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(10)
 }

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/13.fir.kt

@@ -8,7 +8,7 @@ fun <T> case_1(x: T) {
 
     if (y != x) {
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.equals(null)
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>propAny<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.propNullableT
@@ -17,7 +17,7 @@ fun <T> case_1(x: T) {
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>funAny<!>()
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.funNullableT()
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.funNullableAny()
-        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { equals(null) }
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { <!INAPPLICABLE_CANDIDATE!>equals<!>(null) }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { propT }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { <!INAPPLICABLE_CANDIDATE!>propAny<!> }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { propNullableT }
@@ -25,8 +25,8 @@ fun <T> case_1(x: T) {
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { funT() }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { <!INAPPLICABLE_CANDIDATE!>funAny<!>() }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { funNullableT() }
-        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { funNullableAny(); <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.equals(null) }
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.apply { funNullableAny(); <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null) }
-        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.also { <!DEBUG_INFO_EXPRESSION_TYPE("T")!>it<!>.equals(null) }
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.also { <!DEBUG_INFO_EXPRESSION_TYPE("T")!>it<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null) }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.also { <!DEBUG_INFO_EXPRESSION_TYPE("T")!>it<!>.propT }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.also { <!DEBUG_INFO_EXPRESSION_TYPE("T")!>it<!>.<!INAPPLICABLE_CANDIDATE!>propAny<!> }
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.also { <!DEBUG_INFO_EXPRESSION_TYPE("T")!>it<!>.propNullableT }
@@ -51,7 +51,7 @@ fun <T> case_2(x: T?, y: Nothing?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.<!INAPPLICABLE_CANDIDATE!>funAny<!>()
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.funNullableT()
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.funNullableAny()
-        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.apply { equals(null) }
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.apply { <!INAPPLICABLE_CANDIDATE!>equals<!>(null) }
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.apply { propT }
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.apply { <!INAPPLICABLE_CANDIDATE!>propAny<!> }
         <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x<!>.apply { propNullableT }

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/16.fir.kt

@@ -334,7 +334,7 @@ fun <T> case_24(x: Inv<out T?>?, y: Nothing?) {
 fun case_25(x: Int?) {
     val x = (l@ {
         if (x == null) return@l
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int & kotlin.Int")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int & kotlin.Int?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int & kotlin.Int?")!>x<!>.inv()
     })()
 }
@@ -660,7 +660,7 @@ fun case_44(x: Inv<out Inv<out Inv<out Inv<out Inv<out Inv<out Inv<out Number>>>
 fun <T> case_45(x: T) {
     val y = (l@ {
         if (x == null) return@l
-        <!DEBUG_INFO_EXPRESSION_TYPE("T!! & T!!")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T!! & T")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("T!! & T")!>x<!>.equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("T!! & T")!>x<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("T!! & T")!>x<!>.propAny
@@ -677,7 +677,7 @@ fun <T> case_45(x: T) {
 fun <T> case_46(x: T?) {
     (l@ {
         if (x === null) return@l
-        <!DEBUG_INFO_EXPRESSION_TYPE("T?!! & T?!!")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?!! & T?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("T?!! & T?")!>x<!>.equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("T?!! & T?")!>x<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("T?!! & T?")!>x<!>.propAny

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/18.fir.kt

@@ -244,7 +244,7 @@ fun <T>case_18(x: T, f: Boolean) {
     while (f) {
         if (false || false || false || x == nullableNothingProperty) break
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.equals(null)
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.<!INAPPLICABLE_CANDIDATE!>propAny<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("T")!>x<!>.propNullableT
@@ -261,7 +261,7 @@ fun <K, V>case_19(map: MutableMap<K, V>, y: Nothing?) {
     for ((k, v) in map) {
         if (k !== implicitNullableNothingProperty && true && v != y) else { break }
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.equals(null)
+        <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.<!INAPPLICABLE_CANDIDATE!>propAny<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.propNullableT
@@ -271,7 +271,7 @@ fun <K, V>case_19(map: MutableMap<K, V>, y: Nothing?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.funNullableT()
         <!DEBUG_INFO_EXPRESSION_TYPE("K")!>k<!>.funNullableAny()
         <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>.equals(null)
+        <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>.<!INAPPLICABLE_CANDIDATE!>equals<!>(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>.propT
         <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>.<!INAPPLICABLE_CANDIDATE!>propAny<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("V")!>v<!>.propNullableT

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/resolver/SingleCandidateResolver.kt

@@ -68,7 +68,11 @@ class SingleCandidateResolver(
             resolutionParameters.callableSymbol,
             explicitReceiverKind = explicitReceiverKind,
             dispatchReceiverValue = dispatchReceiverValue,
-            implicitExtensionReceiverValue = implicitExtensionReceiverValue,
+            extensionReceiverValue =
+            if (explicitReceiverKind.isExtensionReceiver)
+                callInfo.explicitReceiver?.let { ExpressionReceiverValue(it) }
+            else
+                implicitExtensionReceiverValue,
             scope = null,
         )