[FIR] Make extensionReceiver and dispatchReceiver nullable

Get rid of FirNoReceiverExpression

^KT-59650 Fixed

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirCallableReferenceAccess.kt

@@ -26,8 +26,8 @@ abstract class FirCallableReferenceAccess : FirQualifiedAccessExpression() {
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
     abstract override val explicitReceiver: FirExpression?
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
     abstract override val calleeReference: FirNamedReference
@@ -49,9 +49,9 @@ abstract class FirCallableReferenceAccess : FirQualifiedAccessExpression() {
 
     abstract override fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirComponentCall.kt

@@ -25,8 +25,8 @@ abstract class FirComponentCall : FirFunctionCall() {
     abstract override val annotations: List<FirAnnotation>
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
     abstract override val argumentList: FirArgumentList
@@ -49,9 +49,9 @@ abstract class FirComponentCall : FirFunctionCall() {
 
     abstract override fun replaceTypeArguments(newTypeArguments: List<FirTypeProjection>)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirDelegatedConstructorCall.kt

@@ -23,7 +23,7 @@ abstract class FirDelegatedConstructorCall : FirPureAbstractElement(), FirResolv
     abstract override val argumentList: FirArgumentList
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract val constructedTypeRef: FirTypeRef
-    abstract val dispatchReceiver: FirExpression
+    abstract val dispatchReceiver: FirExpression?
     abstract override val calleeReference: FirReference
     abstract val isThis: Boolean
     abstract val isSuper: Boolean
@@ -42,7 +42,7 @@ abstract class FirDelegatedConstructorCall : FirPureAbstractElement(), FirResolv
 
     abstract fun replaceConstructedTypeRef(newConstructedTypeRef: FirTypeRef)
 
-    abstract fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
     abstract override fun replaceCalleeReference(newCalleeReference: FirReference)
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirFunctionCall.kt

@@ -26,8 +26,8 @@ abstract class FirFunctionCall : FirQualifiedAccessExpression(), FirCall {
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
     abstract override val explicitReceiver: FirExpression?
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
     abstract override val argumentList: FirArgumentList
@@ -50,9 +50,9 @@ abstract class FirFunctionCall : FirQualifiedAccessExpression(), FirCall {
 
     abstract override fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirImplicitInvokeCall.kt

@@ -26,8 +26,8 @@ abstract class FirImplicitInvokeCall : FirFunctionCall() {
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
     abstract override val explicitReceiver: FirExpression?
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
     abstract override val argumentList: FirArgumentList
@@ -50,9 +50,9 @@ abstract class FirImplicitInvokeCall : FirFunctionCall() {
 
     abstract override fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirIntegerLiteralOperatorCall.kt

@@ -31,8 +31,8 @@ abstract class FirIntegerLiteralOperatorCall : FirFunctionCall() {
     abstract override val argumentList: FirArgumentList
     abstract override val calleeReference: FirNamedReference
     abstract override val origin: FirFunctionCallOrigin
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
 
     override fun <R, D> accept(visitor: FirVisitor<R, D>, data: D): R = visitor.visitIntegerLiteralOperatorCall(this, data)
 
@@ -61,9 +61,9 @@ abstract class FirIntegerLiteralOperatorCall : FirFunctionCall() {
 
     abstract override fun replaceCalleeReference(newCalleeReference: FirReference)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     abstract override fun <D> transformAnnotations(transformer: FirTransformer<D>, data: D): FirIntegerLiteralOperatorCall
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirMultiDelegatedConstructorCall.kt

@@ -22,7 +22,7 @@ abstract class FirMultiDelegatedConstructorCall : FirDelegatedConstructorCall()
     abstract override val argumentList: FirArgumentList
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val constructedTypeRef: FirTypeRef
-    abstract override val dispatchReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
     abstract override val calleeReference: FirReference
     abstract override val isThis: Boolean
     abstract override val isSuper: Boolean
@@ -42,7 +42,7 @@ abstract class FirMultiDelegatedConstructorCall : FirDelegatedConstructorCall()
 
     abstract override fun replaceConstructedTypeRef(newConstructedTypeRef: FirTypeRef)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
     abstract override fun replaceCalleeReference(newCalleeReference: FirReference)
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirPropertyAccessExpression.kt

@@ -26,8 +26,8 @@ abstract class FirPropertyAccessExpression : FirQualifiedAccessExpression() {
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
     abstract override val explicitReceiver: FirExpression?
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
 
@@ -49,9 +49,9 @@ abstract class FirPropertyAccessExpression : FirQualifiedAccessExpression() {
 
     abstract override fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirQualifiedAccessExpression.kt

@@ -26,8 +26,8 @@ abstract class FirQualifiedAccessExpression : FirExpression(), FirResolvable, Fi
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract val typeArguments: List<FirTypeProjection>
     abstract val explicitReceiver: FirExpression?
-    abstract val dispatchReceiver: FirExpression
-    abstract val extensionReceiver: FirExpression
+    abstract val dispatchReceiver: FirExpression?
+    abstract val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract val nonFatalDiagnostics: List<ConeDiagnostic>
 
@@ -49,9 +49,9 @@ abstract class FirQualifiedAccessExpression : FirExpression(), FirResolvable, Fi
 
     abstract fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/FirThisReceiverExpression.kt

@@ -26,8 +26,8 @@ abstract class FirThisReceiverExpression : FirQualifiedAccessExpression() {
     abstract override val contextReceiverArguments: List<FirExpression>
     abstract override val typeArguments: List<FirTypeProjection>
     abstract override val explicitReceiver: FirExpression?
-    abstract override val dispatchReceiver: FirExpression
-    abstract override val extensionReceiver: FirExpression
+    abstract override val dispatchReceiver: FirExpression?
+    abstract override val extensionReceiver: FirExpression?
     abstract override val source: KtSourceElement?
     abstract override val nonFatalDiagnostics: List<ConeDiagnostic>
     abstract override val calleeReference: FirThisReference
@@ -49,9 +49,9 @@ abstract class FirThisReceiverExpression : FirQualifiedAccessExpression() {
 
     abstract override fun replaceExplicitReceiver(newExplicitReceiver: FirExpression?)
 
-    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression)
+    abstract override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?)
 
-    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression)
+    abstract override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?)
 
     @FirImplementationDetail
     abstract override fun replaceSource(newSource: KtSourceElement?)

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirAbstractFunctionCallBuilder.kt

@@ -34,8 +34,8 @@ interface FirAbstractFunctionCallBuilder : FirQualifiedAccessExpressionBuilder,
     abstract override val contextReceiverArguments: MutableList<FirExpression>
     abstract override val typeArguments: MutableList<FirTypeProjection>
     abstract override var explicitReceiver: FirExpression?
-    abstract override var dispatchReceiver: FirExpression
-    abstract override var extensionReceiver: FirExpression
+    abstract override var dispatchReceiver: FirExpression?
+    abstract override var extensionReceiver: FirExpression?
     abstract override var source: KtSourceElement?
     abstract override val nonFatalDiagnostics: MutableList<ConeDiagnostic>
     abstract override var argumentList: FirArgumentList

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirCallableReferenceAccessBuilder.kt

@@ -20,7 +20,6 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirQualifiedAccessExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirCallableReferenceAccessImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -39,8 +38,8 @@ class FirCallableReferenceAccessBuilder : FirQualifiedAccessExpressionBuilder, F
     override val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     override val typeArguments: MutableList<FirTypeProjection> = mutableListOf()
     override var explicitReceiver: FirExpression? = null
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
     override var source: KtSourceElement? = null
     override val nonFatalDiagnostics: MutableList<ConeDiagnostic> = mutableListOf()
     lateinit var calleeReference: FirNamedReference

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirComponentCallBuilder.kt

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.fir.expressions.FirFunctionCallOrigin
 import org.jetbrains.kotlin.fir.expressions.builder.FirCallBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirComponentCallImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.references.impl.FirSimpleNamedReference
@@ -43,8 +42,8 @@ class FirComponentCallBuilder : FirCallBuilder, FirAnnotationContainerBuilder, F
     override val annotations: MutableList<FirAnnotation> = mutableListOf()
     val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     val typeArguments: MutableList<FirTypeProjection> = mutableListOf()
-    var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    var extensionReceiver: FirExpression = FirNoReceiverExpression
+    var dispatchReceiver: FirExpression? = null
+    var extensionReceiver: FirExpression? = null
     override var source: KtSourceElement? = null
     val nonFatalDiagnostics: MutableList<ConeDiagnostic> = mutableListOf()
     override var argumentList: FirArgumentList = FirEmptyArgumentList

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirDelegatedConstructorCallBuilder.kt

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.fir.expressions.FirEmptyArgumentList
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.builder.FirCallBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirDelegatedConstructorCallImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.references.impl.FirExplicitSuperReference
 import org.jetbrains.kotlin.fir.references.impl.FirExplicitThisReference
@@ -38,7 +37,7 @@ class FirDelegatedConstructorCallBuilder : FirCallBuilder, FirAnnotationContaine
     override var argumentList: FirArgumentList = FirEmptyArgumentList
     val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     lateinit var constructedTypeRef: FirTypeRef
-    var dispatchReceiver: FirExpression = FirNoReceiverExpression
+    var dispatchReceiver: FirExpression? = null
     lateinit var calleeReference: FirReference
     var isThis: Boolean by kotlin.properties.Delegates.notNull<Boolean>()
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirFunctionCallBuilder.kt

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.fir.expressions.FirFunctionCallOrigin
 import org.jetbrains.kotlin.fir.expressions.builder.FirAbstractFunctionCallBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirFunctionCallImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -42,8 +41,8 @@ open class FirFunctionCallBuilder : FirAbstractFunctionCallBuilder, FirAnnotatio
     override val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     override val typeArguments: MutableList<FirTypeProjection> = mutableListOf()
     override var explicitReceiver: FirExpression? = null
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
     override var source: KtSourceElement? = null
     override val nonFatalDiagnostics: MutableList<ConeDiagnostic> = mutableListOf()
     override var argumentList: FirArgumentList = FirEmptyArgumentList

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirImplicitInvokeCallBuilder.kt

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.fir.expressions.FirImplicitInvokeCall
 import org.jetbrains.kotlin.fir.expressions.builder.FirAbstractFunctionCallBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirImplicitInvokeCallImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -42,8 +41,8 @@ open class FirImplicitInvokeCallBuilder : FirAbstractFunctionCallBuilder, FirAnn
     override val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     override val typeArguments: MutableList<FirTypeProjection> = mutableListOf()
     override var explicitReceiver: FirExpression? = null
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
     override var source: KtSourceElement? = null
     override val nonFatalDiagnostics: MutableList<ConeDiagnostic> = mutableListOf()
     override var argumentList: FirArgumentList = FirEmptyArgumentList

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirIntegerLiteralOperatorCallBuilder.kt

@@ -23,7 +23,6 @@ import org.jetbrains.kotlin.fir.expressions.FirIntegerLiteralOperatorCall
 import org.jetbrains.kotlin.fir.expressions.builder.FirAbstractFunctionCallBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.impl.FirIntegerLiteralOperatorCallImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -47,8 +46,8 @@ open class FirIntegerLiteralOperatorCallBuilder : FirAbstractFunctionCallBuilder
     override var argumentList: FirArgumentList = FirEmptyArgumentList
     override lateinit var calleeReference: FirNamedReference
     override lateinit var origin: FirFunctionCallOrigin
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
 
     override fun build(): FirIntegerLiteralOperatorCall {
         return FirIntegerLiteralOperatorCallImpl(

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirPropertyAccessExpressionBuilder.kt

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirPropertyAccessExpression
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirQualifiedAccessExpressionBuilder
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.expressions.impl.FirPropertyAccessExpressionImpl
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -39,8 +38,8 @@ class FirPropertyAccessExpressionBuilder : FirQualifiedAccessExpressionBuilder,
     override val contextReceiverArguments: MutableList<FirExpression> = mutableListOf()
     override val typeArguments: MutableList<FirTypeProjection> = mutableListOf()
     override var explicitReceiver: FirExpression? = null
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
     override var source: KtSourceElement? = null
     override val nonFatalDiagnostics: MutableList<ConeDiagnostic> = mutableListOf()
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirQualifiedAccessExpressionBuilder.kt

@@ -29,8 +29,8 @@ interface FirQualifiedAccessExpressionBuilder {
     abstract val contextReceiverArguments: MutableList<FirExpression>
     abstract val typeArguments: MutableList<FirTypeProjection>
     abstract var explicitReceiver: FirExpression?
-    abstract var dispatchReceiver: FirExpression
-    abstract var extensionReceiver: FirExpression
+    abstract var dispatchReceiver: FirExpression?
+    abstract var extensionReceiver: FirExpression?
     abstract var source: KtSourceElement?
     abstract val nonFatalDiagnostics: MutableList<ConeDiagnostic>
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/builder/FirThisReceiverExpressionBuilder.kt

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirThisReceiverExpression
 import org.jetbrains.kotlin.fir.expressions.builder.FirExpressionBuilder
 import org.jetbrains.kotlin.fir.expressions.builder.FirQualifiedAccessExpressionBuilder
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.expressions.impl.FirThisReceiverExpressionImpl
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.references.FirThisReference
@@ -65,14 +64,14 @@ class FirThisReceiverExpressionBuilder : FirQualifiedAccessExpressionBuilder, Fi
         }
 
     @Deprecated("Modification of 'dispatchReceiver' has no impact for FirThisReceiverExpressionBuilder", level = DeprecationLevel.HIDDEN)
-    override var dispatchReceiver: FirExpression
+    override var dispatchReceiver: FirExpression?
         get() = throw IllegalStateException()
         set(_) {
             throw IllegalStateException()
         }
 
     @Deprecated("Modification of 'extensionReceiver' has no impact for FirThisReceiverExpressionBuilder", level = DeprecationLevel.HIDDEN)
-    override var extensionReceiver: FirExpression
+    override var extensionReceiver: FirExpression?
         get() = throw IllegalStateException()
         set(_) {
             throw IllegalStateException()

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirCallableReferenceAccessImpl.kt

@@ -32,8 +32,8 @@ internal class FirCallableReferenceAccessImpl(
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var typeArguments: MutableOrEmptyList<FirTypeProjection>,
     override var explicitReceiver: FirExpression?,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
     override var source: KtSourceElement?,
     override var nonFatalDiagnostics: MutableOrEmptyList<ConeDiagnostic>,
     override var calleeReference: FirNamedReference,
@@ -45,10 +45,10 @@ internal class FirCallableReferenceAccessImpl(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
         calleeReference.accept(visitor, data)
     }
@@ -59,10 +59,10 @@ internal class FirCallableReferenceAccessImpl(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         transformCalleeReference(transformer, data)
         return this
@@ -108,11 +108,11 @@ internal class FirCallableReferenceAccessImpl(
         explicitReceiver = newExplicitReceiver
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirComponentCallImpl.kt

@@ -36,8 +36,8 @@ internal class FirComponentCallImpl(
     override var annotations: MutableOrEmptyList<FirAnnotation>,
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var typeArguments: MutableOrEmptyList<FirTypeProjection>,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
     override var source: KtSourceElement?,
     override var nonFatalDiagnostics: MutableOrEmptyList<ConeDiagnostic>,
     override var argumentList: FirArgumentList,
@@ -55,10 +55,10 @@ internal class FirComponentCallImpl(
         calleeReference.accept(visitor, data)
         explicitReceiver.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
     }
 
@@ -70,10 +70,10 @@ internal class FirComponentCallImpl(
         transformCalleeReference(transformer, data)
         explicitReceiver = explicitReceiver.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         return this
     }
@@ -114,11 +114,11 @@ internal class FirComponentCallImpl(
         typeArguments = newTypeArguments.toMutableOrEmpty()
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirDelegatedConstructorCallImpl.kt

@@ -31,7 +31,7 @@ internal class FirDelegatedConstructorCallImpl(
     override var argumentList: FirArgumentList,
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var constructedTypeRef: FirTypeRef,
-    override var dispatchReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
     override var calleeReference: FirReference,
     override val isThis: Boolean,
 ) : FirDelegatedConstructorCall() {
@@ -60,7 +60,7 @@ internal class FirDelegatedConstructorCallImpl(
     }
 
     override fun <D> transformDispatchReceiver(transformer: FirTransformer<D>, data: D): FirDelegatedConstructorCallImpl {
-        dispatchReceiver = dispatchReceiver.transform(transformer, data)
+        dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         return this
     }
 
@@ -85,7 +85,7 @@ internal class FirDelegatedConstructorCallImpl(
         constructedTypeRef = newConstructedTypeRef
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirFunctionCallImpl.kt

@@ -34,8 +34,8 @@ open class FirFunctionCallImpl @FirImplementationDetail constructor(
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var typeArguments: MutableOrEmptyList<FirTypeProjection>,
     override var explicitReceiver: FirExpression?,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
     override var source: KtSourceElement?,
     override var nonFatalDiagnostics: MutableOrEmptyList<ConeDiagnostic>,
     override var argumentList: FirArgumentList,
@@ -48,10 +48,10 @@ open class FirFunctionCallImpl @FirImplementationDetail constructor(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
         argumentList.accept(visitor, data)
         calleeReference.accept(visitor, data)
@@ -63,10 +63,10 @@ open class FirFunctionCallImpl @FirImplementationDetail constructor(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         argumentList = argumentList.transform(transformer, data)
         transformCalleeReference(transformer, data)
@@ -113,11 +113,11 @@ open class FirFunctionCallImpl @FirImplementationDetail constructor(
         explicitReceiver = newExplicitReceiver
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirImplicitInvokeCallImpl.kt

@@ -34,8 +34,8 @@ internal class FirImplicitInvokeCallImpl(
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var typeArguments: MutableOrEmptyList<FirTypeProjection>,
     override var explicitReceiver: FirExpression?,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
     override var source: KtSourceElement?,
     override var nonFatalDiagnostics: MutableOrEmptyList<ConeDiagnostic>,
     override var argumentList: FirArgumentList,
@@ -49,10 +49,10 @@ internal class FirImplicitInvokeCallImpl(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
         argumentList.accept(visitor, data)
         calleeReference.accept(visitor, data)
@@ -64,10 +64,10 @@ internal class FirImplicitInvokeCallImpl(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         argumentList = argumentList.transform(transformer, data)
         transformCalleeReference(transformer, data)
@@ -114,11 +114,11 @@ internal class FirImplicitInvokeCallImpl(
         explicitReceiver = newExplicitReceiver
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirIntegerLiteralOperatorCallImpl.kt

@@ -39,8 +39,8 @@ internal class FirIntegerLiteralOperatorCallImpl(
     override var argumentList: FirArgumentList,
     override var calleeReference: FirNamedReference,
     override val origin: FirFunctionCallOrigin,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
 ) : FirIntegerLiteralOperatorCall() {
     override fun <R, D> acceptChildren(visitor: FirVisitor<R, D>, data: D) {
         annotations.forEach { it.accept(visitor, data) }
@@ -48,10 +48,10 @@ internal class FirIntegerLiteralOperatorCallImpl(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
         argumentList.accept(visitor, data)
         calleeReference.accept(visitor, data)
@@ -63,10 +63,10 @@ internal class FirIntegerLiteralOperatorCallImpl(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         argumentList = argumentList.transform(transformer, data)
         transformCalleeReference(transformer, data)
@@ -94,12 +94,12 @@ internal class FirIntegerLiteralOperatorCallImpl(
     }
 
     override fun <D> transformDispatchReceiver(transformer: FirTransformer<D>, data: D): FirIntegerLiteralOperatorCallImpl {
-        dispatchReceiver = dispatchReceiver.transform(transformer, data)
+        dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         return this
     }
 
     override fun <D> transformExtensionReceiver(transformer: FirTransformer<D>, data: D): FirIntegerLiteralOperatorCallImpl {
-        extensionReceiver = extensionReceiver.transform(transformer, data)
+        extensionReceiver = extensionReceiver?.transform(transformer, data)
         return this
     }
 
@@ -145,11 +145,11 @@ internal class FirIntegerLiteralOperatorCallImpl(
         replaceCalleeReference(newCalleeReference)
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 }

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirLazyDelegatedConstructorCall.kt

@@ -33,7 +33,7 @@ class FirLazyDelegatedConstructorCall @FirImplementationDetail constructor(
     override val annotations: List<FirAnnotation> get() = error("FirLazyDelegatedConstructorCall should be calculated before accessing")
     override val argumentList: FirArgumentList get() = error("FirLazyDelegatedConstructorCall should be calculated before accessing")
     override val contextReceiverArguments: List<FirExpression> get() = error("FirLazyDelegatedConstructorCall should be calculated before accessing")
-    override val dispatchReceiver: FirExpression get() = error("FirLazyDelegatedConstructorCall should be calculated before accessing")
+    override val dispatchReceiver: FirExpression? get() = error("FirLazyDelegatedConstructorCall should be calculated before accessing")
     override val isSuper: Boolean get() = !isThis
 
     override fun <R, D> acceptChildren(visitor: FirVisitor<R, D>, data: D) {
@@ -70,7 +70,7 @@ class FirLazyDelegatedConstructorCall @FirImplementationDetail constructor(
         constructedTypeRef = newConstructedTypeRef
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {}
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {}
 
     override fun replaceCalleeReference(newCalleeReference: FirReference) {
         calleeReference = newCalleeReference

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirMultiDelegatedConstructorCallImpl.kt

@@ -33,7 +33,7 @@ class FirMultiDelegatedConstructorCallImpl @FirImplementationDetail constructor(
     override val argumentList: FirArgumentList get() = delegatedConstructorCalls.last().argumentList
     override val contextReceiverArguments: List<FirExpression> get() = delegatedConstructorCalls.last().contextReceiverArguments
     override val constructedTypeRef: FirTypeRef get() = delegatedConstructorCalls.last().constructedTypeRef
-    override val dispatchReceiver: FirExpression get() = delegatedConstructorCalls.last().dispatchReceiver
+    override val dispatchReceiver: FirExpression? get() = delegatedConstructorCalls.last().dispatchReceiver
     override val calleeReference: FirReference get() = delegatedConstructorCalls.last().calleeReference
     override val isThis: Boolean get() = delegatedConstructorCalls.last().isThis
     override val isSuper: Boolean get() = !isThis
@@ -72,7 +72,7 @@ class FirMultiDelegatedConstructorCallImpl @FirImplementationDetail constructor(
 
     override fun replaceConstructedTypeRef(newConstructedTypeRef: FirTypeRef) {}
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {}
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {}
 
     override fun replaceCalleeReference(newCalleeReference: FirReference) {}
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirPropertyAccessExpressionImpl.kt

@@ -32,8 +32,8 @@ class FirPropertyAccessExpressionImpl @FirImplementationDetail constructor(
     override var contextReceiverArguments: MutableOrEmptyList<FirExpression>,
     override var typeArguments: MutableOrEmptyList<FirTypeProjection>,
     override var explicitReceiver: FirExpression?,
-    override var dispatchReceiver: FirExpression,
-    override var extensionReceiver: FirExpression,
+    override var dispatchReceiver: FirExpression?,
+    override var extensionReceiver: FirExpression?,
     override var source: KtSourceElement?,
     override var nonFatalDiagnostics: MutableOrEmptyList<ConeDiagnostic>,
 ) : FirPropertyAccessExpression() {
@@ -44,10 +44,10 @@ class FirPropertyAccessExpressionImpl @FirImplementationDetail constructor(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
     }
 
@@ -58,10 +58,10 @@ class FirPropertyAccessExpressionImpl @FirImplementationDetail constructor(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         return this
     }
@@ -110,11 +110,11 @@ class FirPropertyAccessExpressionImpl @FirImplementationDetail constructor(
         explicitReceiver = newExplicitReceiver
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/gen/org/jetbrains/kotlin/fir/expressions/impl/FirThisReceiverExpressionImpl.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.fir.diagnostics.ConeDiagnostic
 import org.jetbrains.kotlin.fir.expressions.FirAnnotation
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirThisReceiverExpression
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.references.FirThisReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -38,8 +37,8 @@ internal class FirThisReceiverExpressionImpl(
     override val isImplicit: Boolean,
 ) : FirThisReceiverExpression() {
     override var explicitReceiver: FirExpression? = null
-    override var dispatchReceiver: FirExpression = FirNoReceiverExpression
-    override var extensionReceiver: FirExpression = FirNoReceiverExpression
+    override var dispatchReceiver: FirExpression? = null
+    override var extensionReceiver: FirExpression? = null
 
     override fun <R, D> acceptChildren(visitor: FirVisitor<R, D>, data: D) {
         annotations.forEach { it.accept(visitor, data) }
@@ -47,10 +46,10 @@ internal class FirThisReceiverExpressionImpl(
         typeArguments.forEach { it.accept(visitor, data) }
         explicitReceiver?.accept(visitor, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver.accept(visitor, data)
+            dispatchReceiver?.accept(visitor, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver.accept(visitor, data)
+            extensionReceiver?.accept(visitor, data)
         }
         calleeReference.accept(visitor, data)
     }
@@ -61,10 +60,10 @@ internal class FirThisReceiverExpressionImpl(
         transformTypeArguments(transformer, data)
         explicitReceiver = explicitReceiver?.transform(transformer, data)
         if (dispatchReceiver !== explicitReceiver) {
-            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
         }
         if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-            extensionReceiver = extensionReceiver.transform(transformer, data)
+            extensionReceiver = extensionReceiver?.transform(transformer, data)
         }
         transformCalleeReference(transformer, data)
         return this
@@ -110,11 +109,11 @@ internal class FirThisReceiverExpressionImpl(
         explicitReceiver = newExplicitReceiver
     }
 
-    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression) {
+    override fun replaceDispatchReceiver(newDispatchReceiver: FirExpression?) {
         dispatchReceiver = newDispatchReceiver
     }
 
-    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression) {
+    override fun replaceExtensionReceiver(newExtensionReceiver: FirExpression?) {
         extensionReceiver = newExtensionReceiver
     }
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirExpressionUtil.kt

@@ -15,7 +15,6 @@ import org.jetbrains.kotlin.fir.expressions.builder.buildConstExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildErrorExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildErrorLoop
 import org.jetbrains.kotlin.fir.expressions.impl.FirBlockImpl
-import org.jetbrains.kotlin.fir.expressions.impl.FirNoReceiverExpression
 import org.jetbrains.kotlin.fir.expressions.impl.FirResolvedArgumentList
 import org.jetbrains.kotlin.fir.expressions.impl.FirSingleExpressionBlock
 import org.jetbrains.kotlin.fir.references.*
@@ -135,9 +134,9 @@ private fun FirExpression.unwrapAndFlattenArgumentTo(list: MutableList<FirExpres
 
 val FirVariableAssignment.explicitReceiver: FirExpression? get() = unwrapLValue()?.explicitReceiver
 
-val FirVariableAssignment.dispatchReceiver: FirExpression get() = unwrapLValue()?.dispatchReceiver ?: FirNoReceiverExpression
+val FirVariableAssignment.dispatchReceiver: FirExpression? get() = unwrapLValue()?.dispatchReceiver
 
-val FirVariableAssignment.extensionReceiver: FirExpression get() = unwrapLValue()?.extensionReceiver ?: FirNoReceiverExpression
+val FirVariableAssignment.extensionReceiver: FirExpression? get() = unwrapLValue()?.extensionReceiver
 
 val FirVariableAssignment.calleeReference: FirReference? get() = lValue.toReference()
 
@@ -160,11 +159,11 @@ fun FirExpression.unwrapSmartcastExpression(): FirExpression =
 
 /**
  * A callable reference is bound iff
- * - one of [dispatchReceiver] or [extensionReceiver] is **not** [FirNoReceiverExpression] and
+ * - one of [dispatchReceiver] or [extensionReceiver] is **not** null and
  * - it's not referring to a static member.
  */
 val FirCallableReferenceAccess.isBound: Boolean
-    get() = (dispatchReceiver != FirNoReceiverExpression || extensionReceiver != FirNoReceiverExpression) &&
+    get() = (dispatchReceiver != null || extensionReceiver != null) &&
             calleeReference.toResolvedCallableSymbol()?.isStatic != true
 
 val FirQualifiedAccessExpression.allReceiverExpressions: List<FirExpression>

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/impl/FirNoReceiverExpression.kt

@@ -1,35 +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.fir.expressions.impl
-
-import org.jetbrains.kotlin.KtSourceElement
-import org.jetbrains.kotlin.fir.expressions.FirAnnotation
-import org.jetbrains.kotlin.fir.expressions.FirExpression
-import org.jetbrains.kotlin.fir.types.ConeKotlinType
-import org.jetbrains.kotlin.fir.visitors.FirTransformer
-import org.jetbrains.kotlin.fir.visitors.FirVisitor
-
-object FirNoReceiverExpression : FirExpression() {
-    override val source: KtSourceElement? get() = null
-    override val coneTypeOrNull: ConeKotlinType? get() = null
-    override val annotations: List<FirAnnotation> get() = emptyList()
-
-    override fun <R, D> acceptChildren(visitor: FirVisitor<R, D>, data: D) {}
-
-    override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirNoReceiverExpression {
-        return this
-    }
-
-    override fun replaceAnnotations(newAnnotations: List<FirAnnotation>) {
-        throw AssertionError("Mutating annotations of FirNoReceiverExpression is not supported")
-    }
-
-    override fun <D> transformAnnotations(transformer: FirTransformer<D>, data: D): FirExpression {
-        return this
-    }
-
-    override fun replaceConeTypeOrNull(newConeTypeOrNull: ConeKotlinType?) {}
-}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/renderer/FirRenderer.kt

@@ -662,7 +662,6 @@ class FirRenderer(
                     is FirExpressionStub -> "STUB"
                     is FirUnitExpression -> "Unit"
                     is FirElseIfTrueCondition -> "else"
-                    is FirNoReceiverExpression -> ""
                     else -> "??? ${expression.javaClass}"
                 }
             )
@@ -748,7 +747,7 @@ class FirRenderer(
         override fun visitDelegatedConstructorCall(delegatedConstructorCall: FirDelegatedConstructorCall) {
             if (delegatedConstructorCall !is FirLazyDelegatedConstructorCall) {
                 val dispatchReceiver = delegatedConstructorCall.dispatchReceiver
-                if (dispatchReceiver !is FirNoReceiverExpression) {
+                if (dispatchReceiver != null) {
                     dispatchReceiver.accept(this)
                     print(".")
                 }
@@ -996,17 +995,17 @@ class FirRenderer(
             val extensionReceiver = qualifiedAccess.extensionReceiver
             var hasSomeReceiver = true
             when {
-                dispatchReceiver !is FirNoReceiverExpression && extensionReceiver !is FirNoReceiverExpression -> {
+                dispatchReceiver != null && extensionReceiver != null -> {
                     print("(")
                     dispatchReceiver.accept(this)
                     print(", ")
                     extensionReceiver.accept(this)
                     print(")")
                 }
-                dispatchReceiver !is FirNoReceiverExpression -> {
+                dispatchReceiver != null -> {
                     dispatchReceiver.accept(this)
                 }
-                extensionReceiver !is FirNoReceiverExpression -> {
+                extensionReceiver != null -> {
                     extensionReceiver.accept(this)
                 }
                 explicitReceiver != null -> {

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

@@ -212,8 +212,7 @@ object BuilderConfigurator : AbstractBuilderConfigurator<FirTreeBuilder>(FirTree
             default("argumentList") {
                 value = "FirEmptyArgumentList"
             }
-            default("dispatchReceiver", "FirNoReceiverExpression")
-            useTypes(noReceiverExpressionType)
+            defaultNull("dispatchReceiver")
             useTypes(emptyArgumentListType)
         }
 

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

@@ -26,8 +26,8 @@ object FieldSets {
     val receivers by lazy {
         fieldSet(
             field("explicitReceiver", expression, nullable = true, withReplace = true).withTransform(),
-            field("dispatchReceiver", expression, withReplace = true),
-            field("extensionReceiver", expression, withReplace = true)
+            field("dispatchReceiver", expression, nullable = true, withReplace = true),
+            field("extensionReceiver", expression, nullable = true, withReplace = true)
         )
     }
 

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

@@ -234,8 +234,8 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
 
         integerLiteralOperatorCall.configure {
             // we need methods for transformation of receivers
-            +field("dispatchReceiver", expression, withReplace = true).withTransform()
-            +field("extensionReceiver", expression, withReplace = true).withTransform()
+            +field("dispatchReceiver", expression, nullable = true, withReplace = true).withTransform()
+            +field("extensionReceiver", expression, nullable = true, withReplace = true).withTransform()
         }
 
         comparisonExpression.configure {
@@ -411,7 +411,7 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
 
         delegatedConstructorCall.configure {
             +field("constructedTypeRef", typeRef, withReplace = true)
-            +field("dispatchReceiver", expression, withReplace = true).withTransform()
+            +field("dispatchReceiver", expression, nullable = true, withReplace = true).withTransform()
             +field("calleeReference", reference, withReplace = true)
             generateBooleanFields("this", "super")
         }

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

@@ -56,7 +56,6 @@ val referenceToSimpleExpressionType = generatedType("", "FirExpressionRef<FirExp
 val safeCallCheckedSubjectReferenceType = generatedType("", "FirExpressionRef<FirCheckedSafeCallSubject>")
 
 val firModuleDataType = type("fir", "FirModuleData")
-val noReceiverExpressionType = generatedType("expressions.impl", "FirNoReceiverExpression", firType = true)
 val firImplicitTypeWithoutSourceType = generatedType("types.impl", "FirImplicitTypeRefImplWithoutSource")
 val firQualifierPartType = type("fir.types", "FirQualifierPart")
 val simpleNamedReferenceType = generatedType("references.impl", "FirSimpleNamedReference")

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

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.fir.tree.generator.context
 
 import org.jetbrains.kotlin.fir.tree.generator.model.*
-import org.jetbrains.kotlin.fir.tree.generator.noReceiverExpressionType
 import org.jetbrains.kotlin.fir.tree.generator.util.DummyDelegate
 import kotlin.properties.ReadOnlyProperty
 import kotlin.reflect.KProperty
@@ -27,9 +26,7 @@ abstract class AbstractBuilderConfigurator<T : AbstractFirTreeBuilder>(val firTr
             if (!notNullExplicitReceiver) {
                 defaultNull("explicitReceiver")
             }
-            default("dispatchReceiver", "FirNoReceiverExpression")
-            default("extensionReceiver", "FirNoReceiverExpression")
-            useTypes(noReceiverExpressionType)
+            defaultNull("dispatchReceiver", "extensionReceiver")
         }
 
         fun default(field: String, value: String) {

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

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.fir.tree.generator.context
 
 import org.jetbrains.kotlin.fir.tree.generator.constructClassLikeTypeImport
 import org.jetbrains.kotlin.fir.tree.generator.model.*
-import org.jetbrains.kotlin.fir.tree.generator.noReceiverExpressionType
 import org.jetbrains.kotlin.fir.tree.generator.printer.call
 import org.jetbrains.kotlin.fir.tree.generator.standardClassIdsType
 
@@ -109,10 +108,7 @@ abstract class AbstractFirTreeImplementationConfigurator {
         }
 
         fun defaultNoReceivers() {
-            defaultNull("explicitReceiver")
-            default("dispatchReceiver", "FirNoReceiverExpression")
-            default("extensionReceiver", "FirNoReceiverExpression")
-            useTypes(noReceiverExpressionType)
+            defaultNull("explicitReceiver", "dispatchReceiver", "extensionReceiver")
         }
 
         fun default(field: String, value: String) {

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

@@ -223,7 +223,7 @@ fun SmartPrinter.printImplementation(implementation: Implementation) {
                                     println(
                                         """
                                     |if (dispatchReceiver !== explicitReceiver) {
-                                    |            dispatchReceiver = dispatchReceiver.transform(transformer, data)
+                                    |            dispatchReceiver = dispatchReceiver?.transform(transformer, data)
                                     |        }
                                 """.trimMargin(),
                                     )
@@ -232,7 +232,7 @@ fun SmartPrinter.printImplementation(implementation: Implementation) {
                                     println(
                                         """
                                     |if (extensionReceiver !== explicitReceiver && extensionReceiver !== dispatchReceiver) {
-                                    |            extensionReceiver = extensionReceiver.transform(transformer, data)
+                                    |            extensionReceiver = extensionReceiver?.transform(transformer, data)
                                     |        }
                                 """.trimMargin(),
                                     )