diff --git a/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/fir/Fir2IrTextTestGenerated.java b/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/fir/Fir2IrTextTestGenerated.java
index 196f6d0eea2..9d2c945c9c8 100644
--- a/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/fir/Fir2IrTextTestGenerated.java
+++ b/compiler/fir/fir2ir/tests/org/jetbrains/kotlin/fir/Fir2IrTextTestGenerated.java
@@ -126,6 +126,11 @@ public class Fir2IrTextTestGenerated extends AbstractFir2IrTextTest {
             runTest("compiler/testData/ir/irText/classes/enumWithSecondaryCtor.kt");
         }
 
+        @TestMetadata("implicitNotNullOnDelegatedImplementation.kt")
+        public void testImplicitNotNullOnDelegatedImplementation() throws Exception {
+            runTest("compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.kt");
+        }
+
         @TestMetadata("initBlock.kt")
         public void testInitBlock() throws Exception {
             runTest("compiler/testData/ir/irText/classes/initBlock.kt");
diff --git a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
index 3a3afab13cb..a1edeabfe8a 100644
--- a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
+++ b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
@@ -41,6 +41,7 @@ import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.renderer.DescriptorRendererModifier
 import org.jetbrains.kotlin.renderer.OverrideRenderingPolicy
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.DelegationResolver
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.propertyIfAccessor
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
@@ -142,8 +143,8 @@ class ClassGenerator(
     private fun generateFakeOverrideMemberDeclarations(irClass: IrClass, ktClassOrObject: KtPureClassOrObject) {
         irClass.descriptor.unsubstitutedMemberScope.getContributedDescriptors()
             .mapNotNull {
-                it.safeAs<CallableMemberDescriptor>().takeIf {
-                    it?.kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE
+                it.safeAs<CallableMemberDescriptor>().takeIf { memberDescriptor ->
+                    memberDescriptor?.kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE
                 }
             }
             .sortedByRenderer()
@@ -154,31 +155,25 @@ class ClassGenerator(
 
     private fun generateMembersDeclaredInSupertypeList(irClass: IrClass, ktClassOrObject: KtClassOrObject) {
         val ktSuperTypeList = ktClassOrObject.getSuperTypeList() ?: return
-        val delegatedMembers = irClass.descriptor.unsubstitutedMemberScope
-            .getContributedDescriptors(DescriptorKindFilter.CALLABLES)
-            .filterIsInstance<CallableMemberDescriptor>()
-            .filter { it.kind == CallableMemberDescriptor.Kind.DELEGATION }
-            .sortedByRenderer()
-        if (delegatedMembers.isEmpty()) return
-
         for (ktEntry in ktSuperTypeList.entries) {
             if (ktEntry is KtDelegatedSuperTypeEntry) {
-                generateDelegatedImplementationMembers(irClass, ktEntry, delegatedMembers)
+                generateDelegatedImplementationMembers(irClass, ktEntry)
             }
         }
     }
 
     private fun generateDelegatedImplementationMembers(
         irClass: IrClass,
-        ktEntry: KtDelegatedSuperTypeEntry,
-        delegatedMembers: List<CallableMemberDescriptor>
+        ktEntry: KtDelegatedSuperTypeEntry
     ) {
         val ktDelegateExpression = ktEntry.delegateExpression!!
         val delegateType = getTypeInferredByFrontendOrFail(ktDelegateExpression)
         val superType = getOrFail(BindingContext.TYPE, ktEntry.typeReference!!)
+
         val superTypeConstructorDescriptor = superType.constructor.declarationDescriptor
         val superClass = superTypeConstructorDescriptor as? ClassDescriptor
             ?: throw AssertionError("Unexpected supertype constructor for delegation: $superTypeConstructorDescriptor")
+
         val delegateDescriptor = IrImplementingDelegateDescriptorImpl(irClass.descriptor, delegateType, superType)
         val irDelegateField = context.symbolTable.declareField(
             ktDelegateExpression.startOffsetSkippingComments, ktDelegateExpression.endOffset,
@@ -188,10 +183,17 @@ class ClassGenerator(
         )
         irClass.addMember(irDelegateField)
 
+        val delegatesMap = DelegationResolver.getDelegates(irClass.descriptor, superClass, delegateType)
+        val delegatedMembers = delegatesMap.keys.toList().sortedByRenderer()
+
         for (delegatedMember in delegatedMembers) {
             val overriddenMember = delegatedMember.overriddenDescriptors.find { it.containingDeclaration.original == superClass.original }
             if (overriddenMember != null) {
-                generateDelegatedMember(irClass, irDelegateField, delegatedMember, overriddenMember)
+                val delegateToMember = delegatesMap[delegatedMember]
+                    ?: throw AssertionError(
+                        "No corresponding member in delegate type $delegateType for $delegatedMember overriding $overriddenMember"
+                    )
+                generateDelegatedMember(irClass, irDelegateField, delegatedMember, delegateToMember)
             }
         }
     }
@@ -200,30 +202,27 @@ class ClassGenerator(
         irClass: IrClass,
         irDelegate: IrField,
         delegatedMember: CallableMemberDescriptor,
-        overriddenMember: CallableMemberDescriptor
+        delegateToMember: CallableMemberDescriptor
     ) {
         when (delegatedMember) {
-            is FunctionDescriptor ->
-                generateDelegatedFunction(irClass, irDelegate, delegatedMember, overriddenMember as FunctionDescriptor)
-            is PropertyDescriptor ->
-                generateDelegatedProperty(irClass, irDelegate, delegatedMember, overriddenMember as PropertyDescriptor)
+            is FunctionDescriptor -> generateDelegatedFunction(irClass, irDelegate, delegatedMember, delegateToMember as FunctionDescriptor)
+            is PropertyDescriptor -> generateDelegatedProperty(irClass, irDelegate, delegatedMember, delegateToMember as PropertyDescriptor)
         }
-
     }
 
     private fun generateDelegatedProperty(
         irClass: IrClass,
         irDelegate: IrField,
-        delegated: PropertyDescriptor,
-        overridden: PropertyDescriptor
+        delegatedDescriptor: PropertyDescriptor,
+        delegateToDescriptor: PropertyDescriptor
     ) {
-        irClass.addMember(generateDelegatedProperty(irDelegate, delegated, overridden))
+        irClass.addMember(generateDelegatedProperty(irDelegate, delegatedDescriptor, delegateToDescriptor))
     }
 
     private fun generateDelegatedProperty(
         irDelegate: IrField,
         delegatedDescriptor: PropertyDescriptor,
-        overriddenDescriptor: PropertyDescriptor
+        delegateToDescriptor: PropertyDescriptor
     ): IrProperty {
         val startOffset = irDelegate.startOffset
         val endOffset = irDelegate.endOffset
@@ -233,10 +232,10 @@ class ClassGenerator(
             delegatedDescriptor
         )
 
-        irProperty.getter = generateDelegatedFunction(irDelegate, delegatedDescriptor.getter!!, overriddenDescriptor.getter!!)
+        irProperty.getter = generateDelegatedFunction(irDelegate, delegatedDescriptor.getter!!, delegateToDescriptor.getter!!)
 
         if (delegatedDescriptor.isVar) {
-            irProperty.setter = generateDelegatedFunction(irDelegate, delegatedDescriptor.setter!!, overriddenDescriptor.setter!!)
+            irProperty.setter = generateDelegatedFunction(irDelegate, delegatedDescriptor.setter!!, delegateToDescriptor.setter!!)
         }
         return irProperty
     }
@@ -244,74 +243,82 @@ class ClassGenerator(
     private fun generateDelegatedFunction(
         irClass: IrClass,
         irDelegate: IrField,
-        delegated: FunctionDescriptor,
-        overridden: FunctionDescriptor
+        delegatedDescriptor: FunctionDescriptor,
+        delegateToDescriptor: FunctionDescriptor
     ) {
-        irClass.addMember(generateDelegatedFunction(irDelegate, delegated, overridden))
+        irClass.addMember(generateDelegatedFunction(irDelegate, delegatedDescriptor, delegateToDescriptor))
     }
 
     private fun generateDelegatedFunction(
         irDelegate: IrField,
-        delegated: FunctionDescriptor,
-        overridden: FunctionDescriptor
+        delegatedDescriptor: FunctionDescriptor,
+        delegateToDescriptor: FunctionDescriptor
     ): IrSimpleFunction =
         context.symbolTable.declareSimpleFunctionWithOverrides(
             irDelegate.startOffset, irDelegate.endOffset,
             IrDeclarationOrigin.DELEGATED_MEMBER,
-            delegated
+            delegatedDescriptor
         ).buildWithScope { irFunction ->
             FunctionGenerator(declarationGenerator).generateSyntheticFunctionParameterDeclarations(irFunction)
 
             // TODO could possibly refer to scoped type parameters for property accessors
-            irFunction.returnType = delegated.returnType!!.toIrType()
+            irFunction.returnType = delegatedDescriptor.returnType!!.toIrType()
 
-            irFunction.body = generateDelegateFunctionBody(irDelegate, delegated, overridden, irFunction)
+            irFunction.body = generateDelegateFunctionBody(irDelegate, delegatedDescriptor, delegateToDescriptor, irFunction)
         }
 
     private fun generateDelegateFunctionBody(
         irDelegate: IrField,
-        delegated: FunctionDescriptor,
-        overridden: FunctionDescriptor,
+        delegatedDescriptor: FunctionDescriptor,
+        delegateToDescriptor: FunctionDescriptor,
         irDelegatedFunction: IrSimpleFunction
     ): IrBlockBodyImpl {
         val startOffset = irDelegate.startOffset
         val endOffset = irDelegate.endOffset
+
         val irBlockBody = IrBlockBodyImpl(startOffset, endOffset)
-        val substitutedOverridden = substituteOverriddenDescriptorForDelegate(delegated, overridden)
-        val returnType = substitutedOverridden.returnType!!
-        val irReturnType = returnType.toIrType()
-        val originalSymbol = context.symbolTable.referenceFunction(overridden.original)
+
+        val substitutedDelegateTo = substituteDelegateToDescriptor(delegatedDescriptor, delegateToDescriptor)
+        val returnType = substitutedDelegateTo.returnType!!
+
+        val delegateToSymbol = context.symbolTable.referenceFunction(delegateToDescriptor.original)
+
         val irCall = IrCallImpl(
-            startOffset, endOffset, irReturnType,
-            originalSymbol,
-            substitutedOverridden.typeParametersCount
+            startOffset, endOffset,
+            returnType.toIrType(),
+            delegateToSymbol,
+            substitutedDelegateTo.typeParametersCount
         ).apply {
-            context.callToSubstitutedDescriptorMap[this] = substitutedOverridden
-            val typeArguments = getTypeArgumentsForOverriddenDescriptorDelegatingCall(delegated, overridden)
+            context.callToSubstitutedDescriptorMap[this] = substitutedDelegateTo
+
+            val typeArguments = getTypeArgumentsForOverriddenDescriptorDelegatingCall(delegatedDescriptor, delegateToDescriptor)
             putTypeArguments(typeArguments) { it.toIrType() }
-        }
-        val dispatchReceiverParameter = irDelegatedFunction.dispatchReceiverParameter!!
-        val dispatchReceiverType = dispatchReceiverParameter.type
-        irCall.dispatchReceiver =
-            IrGetFieldImpl(
-                startOffset, endOffset,
-                irDelegate.symbol,
-                irDelegate.type,
-                IrGetValueImpl(
+
+            val dispatchReceiverParameter = irDelegatedFunction.dispatchReceiverParameter!!
+            dispatchReceiver =
+                IrGetFieldImpl(
                     startOffset, endOffset,
-                    dispatchReceiverType,
-                    dispatchReceiverParameter.symbol
+                    irDelegate.symbol,
+                    irDelegate.type,
+                    IrGetValueImpl(
+                        startOffset, endOffset,
+                        dispatchReceiverParameter.type,
+                        dispatchReceiverParameter.symbol
+                    )
                 )
-            )
-        irCall.extensionReceiver =
-            irDelegatedFunction.extensionReceiverParameter?.let { extensionReceiver ->
-                IrGetValueImpl(startOffset, endOffset, extensionReceiver.type, extensionReceiver.symbol)
+
+            extensionReceiver =
+                irDelegatedFunction.extensionReceiverParameter?.let { extensionReceiver ->
+                    IrGetValueImpl(startOffset, endOffset, extensionReceiver.type, extensionReceiver.symbol)
+                }
+
+            mapValueParameters { overriddenValueParameter ->
+                val delegatedValueParameter = delegatedDescriptor.valueParameters[overriddenValueParameter.index]
+                val irDelegatedValueParameter = irDelegatedFunction.getIrValueParameter(delegatedValueParameter)
+                IrGetValueImpl(startOffset, endOffset, irDelegatedValueParameter.type, irDelegatedValueParameter.symbol)
             }
-        irCall.mapValueParameters { overriddenValueParameter ->
-            val delegatedValueParameter = delegated.valueParameters[overriddenValueParameter.index]
-            val irDelegatedValueParameter = irDelegatedFunction.getIrValueParameter(delegatedValueParameter)
-            IrGetValueImpl(startOffset, endOffset, irDelegatedValueParameter.type, irDelegatedValueParameter.symbol)
         }
+
         if (KotlinBuiltIns.isUnit(returnType) || KotlinBuiltIns.isNothing(returnType)) {
             irBlockBody.statements.add(irCall)
         } else {
@@ -322,22 +329,23 @@ class ClassGenerator(
     }
 
     @Suppress("UNCHECKED_CAST")
-    private fun <D : CallableMemberDescriptor> substituteOverriddenDescriptorForDelegate(delegated: D, overridden: D): D =
-        // PropertyAccessorDescriptor doesn't support 'substitute' right now, so we substitute the corresponding property instead.
+    private fun <D : CallableMemberDescriptor> substituteDelegateToDescriptor(delegated: D, overridden: D): D =
+        // PropertyAccessorDescriptor doesn't support 'substitute', so we substitute the corresponding property instead.
         when (overridden) {
-            is PropertyGetterDescriptor -> substituteOverriddenDescriptorForDelegate(
+            is PropertyGetterDescriptor -> substituteDelegateToDescriptor(
                 (delegated as PropertyGetterDescriptor).correspondingProperty,
                 overridden.correspondingProperty
             ).getter as D
-            is PropertySetterDescriptor -> substituteOverriddenDescriptorForDelegate(
+            is PropertySetterDescriptor -> substituteDelegateToDescriptor(
                 (delegated as PropertySetterDescriptor).correspondingProperty,
                 overridden.correspondingProperty
             ).setter as D
             else -> {
+                val delegatedTypeParameters = delegated.typeParameters
                 val substitutor =
                     TypeSubstitutor.create(
                         overridden.typeParameters.associate {
-                            val delegatedDefaultType = delegated.typeParameters[it.index].defaultType
+                            val delegatedDefaultType = delegatedTypeParameters[it.index].defaultType
                             it.typeConstructor to TypeProjectionImpl(delegatedDefaultType)
                         }
                     )
@@ -346,13 +354,13 @@ class ClassGenerator(
         }
 
     private fun getTypeArgumentsForOverriddenDescriptorDelegatingCall(
-        delegated: FunctionDescriptor,
-        overridden: FunctionDescriptor
+        delegatedDescriptor: FunctionDescriptor,
+        delegateToDescriptor: FunctionDescriptor
     ): Map<TypeParameterDescriptor, KotlinType>? {
-        val keys = overridden.propertyIfAccessor.original.typeParameters
+        val keys = delegateToDescriptor.propertyIfAccessor.original.typeParameters
         if (keys.isEmpty()) return null
 
-        val values = delegated.propertyIfAccessor.typeParameters
+        val values = delegatedDescriptor.propertyIfAccessor.typeParameters
 
         val typeArguments = newHashMapWithExpectedSize<TypeParameterDescriptor, KotlinType>(keys.size)
         for ((i, overriddenTypeParameter) in keys.withIndex()) {
diff --git a/compiler/testData/codegen/boxAgainstJava/notNullAssertions/delegation.kt b/compiler/testData/codegen/boxAgainstJava/notNullAssertions/delegation.kt
index 4b16c770283..2274ebd2326 100644
--- a/compiler/testData/codegen/boxAgainstJava/notNullAssertions/delegation.kt
+++ b/compiler/testData/codegen/boxAgainstJava/notNullAssertions/delegation.kt
@@ -1,15 +1,4 @@
-// IGNORE_BACKEND: JVM_IR
-// FILE: Delegation.java
-
-public class Delegation {
-    public static class ReturnNull {
-        public String foo() {
-            return null;
-        }
-    }
-}
-
-// FILE: 1.kt
+// FILE: delegation.kt
 
 interface Tr {
     fun foo(): String
@@ -19,8 +8,7 @@ class DelegateTo : Delegation.ReturnNull(), Tr {
     override fun foo() = super<Delegation.ReturnNull>.foo()
 }
 
-class DelegateFrom : Tr by DelegateTo() {
-}
+class DelegateFrom : Tr by DelegateTo()
 
 fun box(): String {
     try {
@@ -31,3 +19,13 @@ fun box(): String {
         return "OK"
     }
 }
+
+// FILE: Delegation.java
+
+public class Delegation {
+    public static class ReturnNull {
+        public String foo() {
+            return null;
+        }
+    }
+}
diff --git a/compiler/testData/ir/irText/classes/delegatedImplementation.txt b/compiler/testData/ir/irText/classes/delegatedImplementation.txt
index 54da50fa0d5..4b1b3f5791e 100644
--- a/compiler/testData/ir/irText/classes/delegatedImplementation.txt
+++ b/compiler/testData/ir/irText/classes/delegatedImplementation.txt
@@ -209,7 +209,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       $this: VALUE_PARAMETER name:<this> type:<root>.Test1
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='public open fun bar (): kotlin.Int declared in <root>.Test1'
-          CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
+          CALL 'public open fun bar (): kotlin.Int declared in <root>.BaseImpl' type=kotlin.Int origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:Test1$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
               receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.bar' type=<root>.Test1 origin=null
     FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test1, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit
@@ -219,7 +219,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       VALUE_PARAMETER name:x index:0 type:kotlin.Int
       VALUE_PARAMETER name:s index:1 type:kotlin.String
       BLOCK_BODY
-        CALL 'public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+        CALL 'public open fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.BaseImpl' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:Test1$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
             receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.foo' type=<root>.Test1 origin=null
           x: GET_VAR 'x: kotlin.Int declared in <root>.Test1.foo' type=kotlin.Int origin=null
@@ -230,7 +230,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       $this: VALUE_PARAMETER name:<this> type:<root>.Test1
       $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
       BLOCK_BODY
-        CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+        CALL 'public open fun qux (): kotlin.Unit declared in <root>.BaseImpl' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:Test1$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
             receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.qux' type=<root>.Test1 origin=null
           $receiver: GET_VAR '<this>: kotlin.String declared in <root>.Test1.qux' type=kotlin.String origin=null
@@ -262,7 +262,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       $this: VALUE_PARAMETER name:<this> type:<root>.Test2
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='public open fun bar (): kotlin.Int declared in <root>.Test2'
-          CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
+          CALL 'public open fun bar (): kotlin.Int declared in <root>.BaseImpl' type=kotlin.Int origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:Test2$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
               receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.bar' type=<root>.Test2 origin=null
     FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test2, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit
@@ -272,7 +272,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       VALUE_PARAMETER name:x index:0 type:kotlin.Int
       VALUE_PARAMETER name:s index:1 type:kotlin.String
       BLOCK_BODY
-        CALL 'public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+        CALL 'public open fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.BaseImpl' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:Test2$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
             receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.foo' type=<root>.Test2 origin=null
           x: GET_VAR 'x: kotlin.Int declared in <root>.Test2.foo' type=kotlin.Int origin=null
@@ -283,7 +283,7 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       $this: VALUE_PARAMETER name:<this> type:<root>.Test2
       $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
       BLOCK_BODY
-        CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+        CALL 'public open fun qux (): kotlin.Unit declared in <root>.BaseImpl' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:Test2$IBase$delegate type:<root>.BaseImpl visibility:private [final]' type=<root>.BaseImpl origin=null
             receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.qux' type=<root>.Test2 origin=null
           $receiver: GET_VAR '<this>: kotlin.String declared in <root>.Test2.qux' type=kotlin.String origin=null
diff --git a/compiler/testData/ir/irText/classes/delegatedImplementationWithExplicitOverride.txt b/compiler/testData/ir/irText/classes/delegatedImplementationWithExplicitOverride.txt
index 42e1844d749..d8d93e215f1 100644
--- a/compiler/testData/ir/irText/classes/delegatedImplementationWithExplicitOverride.txt
+++ b/compiler/testData/ir/irText/classes/delegatedImplementationWithExplicitOverride.txt
@@ -61,7 +61,7 @@ FILE fqName:<root> fileName:/delegatedImplementationWithExplicitOverride.kt
         public abstract fun foo (): kotlin.Unit declared in <root>.IFooBar
       $this: VALUE_PARAMETER name:<this> type:<root>.C
       BLOCK_BODY
-        CALL 'public abstract fun foo (): kotlin.Unit declared in <root>.IFooBar' type=kotlin.Unit origin=null
+        CALL 'public open fun foo (): kotlin.Unit declared in <root>.FooBarImpl' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:C$IFooBar$delegate type:<root>.FooBarImpl visibility:private [final]' type=<root>.FooBarImpl origin=null
             receiver: GET_VAR '<this>: <root>.C declared in <root>.C.foo' type=<root>.C origin=null
     FUN name:bar visibility:public modality:OPEN <> ($this:<root>.C) returnType:kotlin.Unit
diff --git a/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.fir.txt b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.fir.txt
new file mode 100644
index 00000000000..b8d342dbc0a
--- /dev/null
+++ b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.fir.txt
@@ -0,0 +1,229 @@
+FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
+  CLASS INTERFACE name:IFoo modality:ABSTRACT visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.IFoo
+    FUN name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K1 modality:FINAL visibility:public superTypes:[<root>.JFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K1
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K1 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K1 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:OPEN <> ($this:<root>.JFoo) returnType:kotlin.String [fake_override,operator]
+      overridden:
+        public open fun foo (): kotlin.String [operator] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.JFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K2 modality:FINAL visibility:public superTypes:[<root>.JFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K2
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K2 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K2 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
+    FUN name:foo visibility:public modality:FINAL <> ($this:<root>.K2) returnType:kotlin.String
+      $this: VALUE_PARAMETER name:<this> type:<root>.K2
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun foo (): kotlin.String declared in <root>.K2'
+          CALL 'public open fun foo (): kotlin.String [operator] declared in <root>.JFoo' type=kotlin.String origin=null
+            $this: ERROR_CALL 'Unresolved reference: super<R|JFoo|>' type=<root>.JFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K3 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K3
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K3 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JUnrelatedFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K3 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K4 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K4
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K4 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JUnrelatedFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K4 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]'
+    FUN name:foo visibility:public modality:FINAL <> ($this:<root>.K4) returnType:kotlin.String?
+      $this: VALUE_PARAMETER name:<this> type:<root>.K4
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public final fun foo (): kotlin.String? declared in <root>.K4'
+          CALL 'public open fun foo (): kotlin.String? [operator] declared in <root>.JUnrelatedFoo' type=kotlin.String? origin=null
+            $this: ERROR_CALL 'Unresolved reference: super<R|JUnrelatedFoo|>' type=<root>.JUnrelatedFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestJFoo modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestJFoo
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestJFoo [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestJFoo modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK1 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK1
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK1 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK1 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK2 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK2
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK2 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK2 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK3 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK3
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK3 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK3 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK4 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK4
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK4 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK4 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
diff --git a/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.kt b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.kt
new file mode 100644
index 00000000000..6a3105fd7c3
--- /dev/null
+++ b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.kt
@@ -0,0 +1,47 @@
+// FILE: implicitNotNullOnDelegatedImplementation.kt
+interface IFoo {
+    fun foo(): String
+}
+
+class K1 : JFoo()
+
+class K2 : JFoo() {
+    override fun foo() = super.foo()
+}
+
+class K3 : JUnrelatedFoo(), IFoo
+
+class K4 : JUnrelatedFoo(), IFoo {
+    override fun foo() = super.foo()
+}
+
+class TestJFoo : IFoo by JFoo() {
+    // nullability assertion in 'foo()'
+}
+
+class TestK1 : IFoo by K1() {
+    // nullability assertion in 'foo()'
+}
+
+class TestK2 : IFoo by K2() {
+    // no nullability assertion in 'foo()'
+}
+
+class TestK3 : IFoo by K3() {
+    // no nullability assertion in 'foo()'
+}
+
+class TestK4 : IFoo by K4() {
+    // nullability assertion in 'foo()'
+}
+
+
+// FILE: JFoo.java
+public class JFoo implements IFoo {
+    public String foo() { return null; }
+}
+
+// FILE: JUnrelatedFoo.java
+public class JUnrelatedFoo {
+    public String foo() { return null; }
+} 
\ No newline at end of file
diff --git a/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.txt b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.txt
new file mode 100644
index 00000000000..f69e13973b2
--- /dev/null
+++ b/compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.txt
@@ -0,0 +1,285 @@
+FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
+  CLASS INTERFACE name:IFoo modality:ABSTRACT visibility:public superTypes:[kotlin.Any]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.IFoo
+    FUN name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String declared in kotlin.Any
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K1 modality:FINAL visibility:public superTypes:[<root>.JFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K1
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K1 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K1 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:OPEN <> ($this:<root>.JFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun foo (): kotlin.String declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.JFoo
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K2 modality:FINAL visibility:public superTypes:[<root>.JFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K2
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K2 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K2 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
+    FUN name:foo visibility:public modality:OPEN <> ($this:<root>.K2) returnType:kotlin.String
+      overridden:
+        public open fun foo (): kotlin.String declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.K2
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.K2'
+          TYPE_OP type=kotlin.String origin=IMPLICIT_NOTNULL typeOperand=kotlin.String
+            CALL 'public open fun foo (): kotlin.String declared in <root>.JFoo' superQualifier='CLASS IR_EXTERNAL_JAVA_DECLARATION_STUB CLASS name:JFoo modality:OPEN visibility:public superTypes:[<root>.IFoo]' type=kotlin.String origin=null
+              $this: GET_VAR '<this>: <root>.K2 declared in <root>.K2.foo' type=<root>.K2 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.JFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K3 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K3
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K3 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JUnrelatedFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K3 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]'
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.JUnrelatedFoo
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:OPEN <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun foo (): kotlin.String? declared in <root>.JUnrelatedFoo
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.JUnrelatedFoo
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.JUnrelatedFoo
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:K4 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.K4
+    CONSTRUCTOR visibility:public <> () returnType:<root>.K4 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JUnrelatedFoo'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K4 modality:FINAL visibility:public superTypes:[<root>.JUnrelatedFoo; <root>.IFoo]'
+    FUN name:foo visibility:public modality:OPEN <> ($this:<root>.K4) returnType:kotlin.String?
+      overridden:
+        public open fun foo (): kotlin.String? declared in <root>.JUnrelatedFoo
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.K4
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String? declared in <root>.K4'
+          CALL 'public open fun foo (): kotlin.String? declared in <root>.JUnrelatedFoo' superQualifier='CLASS IR_EXTERNAL_JAVA_DECLARATION_STUB CLASS name:JUnrelatedFoo modality:OPEN visibility:public superTypes:[kotlin.Any]' type=kotlin.String? origin=null
+            $this: GET_VAR '<this>: <root>.K4 declared in <root>.K4.foo' type=<root>.K4 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.JUnrelatedFoo
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.JUnrelatedFoo
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.JUnrelatedFoo
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestJFoo modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestJFoo
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestJFoo [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestJFoo modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FIELD DELEGATE name:TestJFoo$IFoo$delegate type:<root>.JFoo visibility:private [final]
+      EXPRESSION_BODY
+        CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo' type=<root>.JFoo origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestJFoo) returnType:kotlin.String
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.TestJFoo
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestJFoo'
+          TYPE_OP type=kotlin.String origin=IMPLICIT_NOTNULL typeOperand=kotlin.String
+            CALL 'public open fun foo (): kotlin.String declared in <root>.JFoo' type=kotlin.String origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:TestJFoo$IFoo$delegate type:<root>.JFoo visibility:private [final]' type=<root>.JFoo origin=null
+                receiver: GET_VAR '<this>: <root>.TestJFoo declared in <root>.TestJFoo.foo' type=<root>.TestJFoo origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK1 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK1
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK1 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK1 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FIELD DELEGATE name:TestK1$IFoo$delegate type:<root>.K1 visibility:private [final]
+      EXPRESSION_BODY
+        CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K1' type=<root>.K1 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK1) returnType:kotlin.String
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.TestK1
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK1'
+          TYPE_OP type=kotlin.String origin=IMPLICIT_NOTNULL typeOperand=kotlin.String
+            CALL 'public open fun foo (): kotlin.String [fake_override] declared in <root>.K1' type=kotlin.String origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:TestK1$IFoo$delegate type:<root>.K1 visibility:private [final]' type=<root>.K1 origin=null
+                receiver: GET_VAR '<this>: <root>.TestK1 declared in <root>.TestK1.foo' type=<root>.TestK1 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK2 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK2
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK2 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK2 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FIELD DELEGATE name:TestK2$IFoo$delegate type:<root>.K2 visibility:private [final]
+      EXPRESSION_BODY
+        CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K2' type=<root>.K2 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK2) returnType:kotlin.String
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.TestK2
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK2'
+          CALL 'public open fun foo (): kotlin.String declared in <root>.K2' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:TestK2$IFoo$delegate type:<root>.K2 visibility:private [final]' type=<root>.K2 origin=null
+              receiver: GET_VAR '<this>: <root>.TestK2 declared in <root>.TestK2.foo' type=<root>.TestK2 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK3 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK3
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK3 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK3 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FIELD DELEGATE name:TestK3$IFoo$delegate type:<root>.K3 visibility:private [final]
+      EXPRESSION_BODY
+        CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K3' type=<root>.K3 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK3) returnType:kotlin.String
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.TestK3
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK3'
+          CALL 'public open fun foo (): kotlin.String [fake_override] declared in <root>.K3' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:TestK3$IFoo$delegate type:<root>.K3 visibility:private [final]' type=<root>.K3 origin=null
+              receiver: GET_VAR '<this>: <root>.TestK3 declared in <root>.TestK3.foo' type=<root>.TestK3 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+  CLASS CLASS name:TestK4 modality:FINAL visibility:public superTypes:[<root>.IFoo]
+    $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestK4
+    CONSTRUCTOR visibility:public <> () returnType:<root>.TestK4 [primary]
+      BLOCK_BODY
+        DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK4 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
+    FIELD DELEGATE name:TestK4$IFoo$delegate type:<root>.K4 visibility:private [final]
+      EXPRESSION_BODY
+        CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K4' type=<root>.K4 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK4) returnType:kotlin.String
+      overridden:
+        public abstract fun foo (): kotlin.String declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:<root>.TestK4
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK4'
+          TYPE_OP type=kotlin.String origin=IMPLICIT_NOTNULL typeOperand=kotlin.String
+            CALL 'public open fun foo (): kotlin.String? declared in <root>.K4' type=kotlin.String? origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:TestK4$IFoo$delegate type:<root>.K4 visibility:private [final]' type=<root>.K4 origin=null
+                receiver: GET_VAR '<this>: <root>.TestK4 declared in <root>.TestK4.foo' type=<root>.TestK4 origin=null
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
+      overridden:
+        public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+      VALUE_PARAMETER name:other index:0 type:kotlin.Any?
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
+      overridden:
+        public open fun hashCode (): kotlin.Int [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
+      overridden:
+        public open fun toString (): kotlin.String [fake_override] declared in <root>.IFoo
+      $this: VALUE_PARAMETER name:<this> type:kotlin.Any
diff --git a/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java b/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
index 0084f07b08a..6167f27e06c 100644
--- a/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
@@ -125,6 +125,11 @@ public class IrTextTestCaseGenerated extends AbstractIrTextTestCase {
             runTest("compiler/testData/ir/irText/classes/enumWithSecondaryCtor.kt");
         }
 
+        @TestMetadata("implicitNotNullOnDelegatedImplementation.kt")
+        public void testImplicitNotNullOnDelegatedImplementation() throws Exception {
+            runTest("compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.kt");
+        }
+
         @TestMetadata("initBlock.kt")
         public void testInitBlock() throws Exception {
             runTest("compiler/testData/ir/irText/classes/initBlock.kt");