diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt
index 4c8e8ccd3ba..8d40975a121 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt
@@ -10,10 +10,8 @@ import org.jetbrains.kotlin.backend.common.ir.isOverridable
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities as OldVisibilities
 import org.jetbrains.kotlin.fir.Visibilities
-import org.jetbrains.kotlin.fir.backend.Fir2IrComponents
-import org.jetbrains.kotlin.fir.backend.FirMetadataSource
+import org.jetbrains.kotlin.fir.backend.*
 import org.jetbrains.kotlin.fir.backend.declareThisReceiverParameter
-import org.jetbrains.kotlin.fir.backend.isOverriding
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.builder.buildProperty
 import org.jetbrains.kotlin.fir.declarations.builder.buildSimpleFunction
@@ -233,6 +231,10 @@ internal class DelegatedMemberGenerator(
                     }
                     irTypeSubstitutor = IrTypeSubstitutor(substParameters, substArguments, irBuiltIns)
                 }
+                superFunction.extensionReceiverParameter?.let {
+                    val substitutedType = if (addTypeSubstitution) irTypeSubstitutor.substitute(it.type) else it.type
+                    extensionReceiverParameter = declareThisReceiverParameter(symbolTable, substitutedType, origin)
+                }
                 valueParameters = superFunction.valueParameters.map { valueParameter ->
                     val parameterDescriptor = WrappedValueParameterDescriptor()
                     val substedType = if (addTypeSubstitution) irTypeSubstitutor.substitute(valueParameter.type) else valueParameter.type
diff --git a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtValDelegationWithInlineClassParameterTypes.kt b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtValDelegationWithInlineClassParameterTypes.kt
index f7d09410c3b..c522ffff3c2 100644
--- a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtValDelegationWithInlineClassParameterTypes.kt
+++ b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtValDelegationWithInlineClassParameterTypes.kt
@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 import kotlin.test.assertEquals
 
 inline class S(val x: String)
diff --git a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtVarDelegationWithInlineClassParameterTypes.kt b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtVarDelegationWithInlineClassParameterTypes.kt
index e637e022329..7808a26a6ab 100644
--- a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtVarDelegationWithInlineClassParameterTypes.kt
+++ b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberExtVarDelegationWithInlineClassParameterTypes.kt
@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 
 import kotlin.test.assertEquals
 
diff --git a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationToInlineClassWithInlineClassParameterTypes.kt b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationToInlineClassWithInlineClassParameterTypes.kt
index 648f32a4ddd..7f9223bec32 100644
--- a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationToInlineClassWithInlineClassParameterTypes.kt
+++ b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationToInlineClassWithInlineClassParameterTypes.kt
@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 import kotlin.test.assertEquals
 
 inline class S(val x: String)
diff --git a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationWithInlineClassParameterTypes.kt b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationWithInlineClassParameterTypes.kt
index b95884783ae..69522dcf2b9 100644
--- a/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationWithInlineClassParameterTypes.kt
+++ b/compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegationWithInlineClassParameterTypes.kt
@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 import kotlin.test.assertEquals
 
 inline class S(val x: String)
diff --git a/compiler/testData/ir/irText/classes/delegatedImplementation.fir.txt b/compiler/testData/ir/irText/classes/delegatedImplementation.fir.txt
index 2a87a8673c5..115b7bd8904 100644
--- a/compiler/testData/ir/irText/classes/delegatedImplementation.fir.txt
+++ b/compiler/testData/ir/irText/classes/delegatedImplementation.fir.txt
@@ -224,14 +224,16 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
           CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
               receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.bar' type=<root>.Test1 origin=null
-    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test1) returnType:kotlin.Unit
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test1, $receiver:kotlin.String) returnType:kotlin.Unit
       overridden:
         public abstract fun qux (): kotlin.Unit declared in <root>.IBase
       $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1
+      $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:kotlin.String
       BLOCK_BODY
         CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]' type=<root>.IBase 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
     FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
@@ -281,14 +283,16 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
           CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
               receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.bar' type=<root>.Test2 origin=null
-    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Unit
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test2, $receiver:kotlin.String) returnType:kotlin.Unit
       overridden:
         public abstract fun qux (): kotlin.Unit declared in <root>.IBase
       $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+      $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:kotlin.String
       BLOCK_BODY
         CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
             receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.qux' type=<root>.Test2 origin=null
+          $receiver: GET_VAR '<this>: kotlin.String declared in <root>.Test2.qux' type=kotlin.String origin=null
     FIELD DELEGATE name:<$$delegate_0> type:<root>.IBase visibility:local [final]
     PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [val]
       FUN DELEGATED_MEMBER name:<get-x> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.String
@@ -324,37 +328,43 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
               receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-y>' type=<root>.Test2 origin=null
             <set-?>: GET_VAR '<set-?>: kotlin.Int declared in <root>.Test2.<set-y>' type=kotlin.Int origin=null
     PROPERTY DELEGATED_MEMBER name:z1 visibility:public modality:OPEN [val]
-      FUN DELEGATED_MEMBER name:<get-z1> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
+      FUN DELEGATED_MEMBER name:<get-z1> visibility:public modality:OPEN <> ($this:<root>.Test2, $receiver:kotlin.Byte) returnType:kotlin.Int
         correspondingProperty: PROPERTY DELEGATED_MEMBER name:z1 visibility:public modality:OPEN [val]
         overridden:
           public abstract fun <get-z1> (): kotlin.Int declared in <root>.IOther
         $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:kotlin.Byte
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='public open fun <get-z1> (): kotlin.Int declared in <root>.Test2'
             CALL 'public abstract fun <get-z1> (): kotlin.Int declared in <root>.IOther' type=kotlin.Int origin=null
               $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_1> type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
                 receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-z1>' type=<root>.Test2 origin=null
+              $receiver: GET_VAR '<this>: kotlin.Byte declared in <root>.Test2.<get-z1>' type=kotlin.Byte origin=null
     PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
-      FUN DELEGATED_MEMBER name:<get-z2> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
+      FUN DELEGATED_MEMBER name:<get-z2> visibility:public modality:OPEN <> ($this:<root>.Test2, $receiver:kotlin.Byte) returnType:kotlin.Int
         correspondingProperty: PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <get-z2> (): kotlin.Int declared in <root>.IOther
         $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:kotlin.Byte
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='public open fun <get-z2> (): kotlin.Int declared in <root>.Test2'
             CALL 'public abstract fun <get-z2> (): kotlin.Int declared in <root>.IOther' type=kotlin.Int origin=null
               $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_1> type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
                 receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-z2>' type=<root>.Test2 origin=null
-      FUN DELEGATED_MEMBER name:<set-z2> visibility:public modality:OPEN <> ($this:<root>.Test2, <set-?>:kotlin.Int) returnType:kotlin.Unit
+              $receiver: GET_VAR '<this>: kotlin.Byte declared in <root>.Test2.<get-z2>' type=kotlin.Byte origin=null
+      FUN DELEGATED_MEMBER name:<set-z2> visibility:public modality:OPEN <> ($this:<root>.Test2, $receiver:kotlin.Byte, <set-?>:kotlin.Int) returnType:kotlin.Unit
         correspondingProperty: PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <set-z2> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther
         $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:kotlin.Byte
         VALUE_PARAMETER DELEGATED_MEMBER name:<set-?> index:0 type:kotlin.Int
         BLOCK_BODY
           CALL 'public abstract fun <set-z2> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther' type=kotlin.Unit origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_1> type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
               receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-z2>' type=<root>.Test2 origin=null
+            $receiver: GET_VAR '<this>: kotlin.Byte declared in <root>.Test2.<set-z2>' type=kotlin.Byte origin=null
             <set-?>: GET_VAR '<set-?>: kotlin.Int declared in <root>.Test2.<set-z2>' type=kotlin.Int origin=null
     FIELD DELEGATE name:<$$delegate_1> type:<root>.IOther visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
diff --git a/compiler/testData/ir/irText/declarations/kt35550.fir.txt b/compiler/testData/ir/irText/declarations/kt35550.fir.txt
index 26a573ae014..2a5e7545ff5 100644
--- a/compiler/testData/ir/irText/declarations/kt35550.fir.txt
+++ b/compiler/testData/ir/irText/declarations/kt35550.fir.txt
@@ -34,18 +34,20 @@ FILE fqName:<root> fileName:/kt35550.kt
           receiver: GET_VAR '<this>: <root>.A declared in <root>.A' type=<root>.A origin=null
           value: GET_VAR 'i: <root>.I declared in <root>.A.<init>' type=<root>.I origin=null
     PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
-      FUN DELEGATED_MEMBER name:<get-id> visibility:public modality:OPEN <T> ($this:<root>.A) returnType:T of <root>.I.<get-id>
+      FUN DELEGATED_MEMBER name:<get-id> visibility:public modality:OPEN <T> ($this:<root>.A, $receiver:T of <root>.A.<get-id>) returnType:T of <root>.I.<get-id>
         correspondingProperty: PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
         overridden:
           public open fun <get-id> <T> (): T of <root>.I.<get-id> declared in <root>.I
-        TYPE_PARAMETER DELEGATED_MEMBER name:T index:0 variance: superTypes:[]
+        TYPE_PARAMETER DELEGATED_MEMBER name:T index:0 variance: superTypes:[kotlin.Any?]
         $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.A
+        $receiver: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:T of <root>.A.<get-id>
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='public open fun <get-id> <T> (): T of <root>.I.<get-id> declared in <root>.A'
             CALL 'public open fun <get-id> <T> (): T of <root>.I.<get-id> declared in <root>.I' type=T of <root>.A.<get-id> origin=null
               <T>: <none>
               $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.I visibility:local [final]' type=<root>.I origin=null
                 receiver: GET_VAR '<this>: <root>.A declared in <root>.A.<get-id>' type=<root>.A origin=null
+              $receiver: GET_VAR '<this>: T of <root>.A.<get-id> declared in <root>.A.<get-id>' type=T of <root>.A.<get-id> origin=null
     FIELD DELEGATE name:<$$delegate_0> type:<root>.I visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
diff --git a/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.fir.txt b/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.fir.txt
index f7603cb53f4..3ed3b69eda8 100644
--- a/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.fir.txt
+++ b/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.fir.txt
@@ -62,7 +62,7 @@ FILE fqName:<root> fileName:/delegatedMembers.kt
     FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <X> ($this:<root>.Test<TT of <root>.Test>, t:TT of <root>.Test, x:X of <root>.Test.qux) returnType:kotlin.Unit
       overridden:
         public abstract fun qux <X> (t: T of <root>.IBase, x: X of <root>.IBase.qux): kotlin.Unit declared in <root>.IBase
-      TYPE_PARAMETER DELEGATED_MEMBER name:X index:0 variance: superTypes:[]
+      TYPE_PARAMETER DELEGATED_MEMBER name:X index:0 variance: superTypes:[kotlin.Any?]
       $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test<TT of <root>.Test>
       VALUE_PARAMETER DELEGATED_MEMBER name:t index:0 type:TT of <root>.Test
       VALUE_PARAMETER DELEGATED_MEMBER name:x index:1 type:X of <root>.Test.qux