diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
index b8713caaeaa..5d34c893c4a 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
@@ -55,12 +55,15 @@ import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.IrErrorTypeImpl
 import org.jetbrains.kotlin.ir.util.SymbolTable
 import org.jetbrains.kotlin.ir.util.functions
+import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.psi
+import org.jetbrains.kotlin.psi.KtParameter
 import org.jetbrains.kotlin.psi.KtQualifiedExpression
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.startOffsetSkippingComments
+import org.jetbrains.kotlin.resolve.calls.util.isSingleUnderscore
 import org.jetbrains.kotlin.types.ConstantValueKind
 import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.util.OperatorNameConventions
@@ -488,16 +491,18 @@ internal fun IrDeclarationParent.declareThisReceiverParameter(
     thisType: IrType,
     thisOrigin: IrDeclarationOrigin,
     startOffset: Int = this.startOffset,
-    endOffset: Int = this.endOffset
-): IrValueParameter =
-    symbolTable.irFactory.createValueParameter(
+    endOffset: Int = this.endOffset,
+    name: Name = SpecialNames.THIS
+): IrValueParameter {
+    return symbolTable.irFactory.createValueParameter(
         startOffset, endOffset, thisOrigin, IrValueParameterSymbolImpl(),
-        SpecialNames.THIS, UNDEFINED_PARAMETER_INDEX, thisType,
+        name, UNDEFINED_PARAMETER_INDEX, thisType,
         varargElementType = null, isCrossinline = false, isNoinline = false,
         isHidden = false, isAssignable = false
     ).apply {
         this.parent = this@declareThisReceiverParameter
     }
+}
 
 fun FirClass.irOrigin(firProvider: FirProvider): IrDeclarationOrigin = when {
     firProvider.getFirClassifierContainerFileIfAny(symbol) != null -> IrDeclarationOrigin.DEFINED
@@ -615,6 +620,15 @@ fun FirSession.createFilesWithGeneratedDeclarations(): List<FirFile> {
 fun FirDeclaration?.computeIrOrigin(predefinedOrigin: IrDeclarationOrigin? = null): IrDeclarationOrigin {
     return predefinedOrigin
         ?: (this?.origin as? FirDeclarationOrigin.Plugin)?.let { IrPluginDeclarationOrigin(it.key) }
+        ?: ((this as? FirValueParameter)?.source.psi as? KtParameter)?.let {
+            if (it.isSingleUnderscore) {
+                IrDeclarationOrigin.UNDERSCORE_PARAMETER
+            } else if (it.destructuringDeclaration != null) {
+                IrDeclarationOrigin.DESTRUCTURED_OBJECT_PARAMETER
+            } else {
+                null
+            }
+        }
         ?: IrDeclarationOrigin.DEFINED
 }
 
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt
index 939b115b0ea..5c8be33e211 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt
@@ -338,12 +338,17 @@ class Fir2IrDeclarationStorage(
                     else parentPropertyReceiverType
                 if (receiverTypeRef != null) {
                     extensionReceiverParameter = receiverTypeRef.convertWithOffsets { startOffset, endOffset ->
+                        val name = (function as? FirAnonymousFunction)?.label?.name?.let {
+                            val suffix = it.takeIf(Name::isValidIdentifier) ?: "\$receiver"
+                            Name.identifier("\$this\$$suffix")
+                        } ?: SpecialNames.THIS
                         declareThisReceiverParameter(
                             symbolTable,
                             thisType = receiverTypeRef.toIrType(typeContext),
                             thisOrigin = thisOrigin,
                             startOffset = startOffset,
-                            endOffset = endOffset
+                            endOffset = endOffset,
+                            name = name
                         )
                     }
                 }
diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/Fir2IrTextTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/Fir2IrTextTestGenerated.java
index 7ae24515fde..ef170775ceb 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/Fir2IrTextTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/ir/Fir2IrTextTestGenerated.java
@@ -2462,6 +2462,12 @@ public class Fir2IrTextTestGenerated extends AbstractFir2IrTextTest {
             runTest("compiler/testData/ir/irText/lambdas/justLambda.kt");
         }
 
+        @Test
+        @TestMetadata("lambdaReturningUnit.kt")
+        public void testLambdaReturningUnit() throws Exception {
+            runTest("compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt");
+        }
+
         @Test
         @TestMetadata("localFunction.kt")
         public void testLocalFunction() throws Exception {
diff --git a/compiler/testData/codegen/box/fir/noSymbolForIntRangeIterator.fir.ir.txt b/compiler/testData/codegen/box/fir/noSymbolForIntRangeIterator.fir.ir.txt
index 66126afe3e0..b092df3d6de 100644
--- a/compiler/testData/codegen/box/fir/noSymbolForIntRangeIterator.fir.ir.txt
+++ b/compiler/testData/codegen/box/fir/noSymbolForIntRangeIterator.fir.ir.txt
@@ -69,7 +69,7 @@ FILE fqName:<root> fileName:/noSymbolForIntRangeIterator.kt
                     CALL 'public final fun buildString (builderAction: @[ExtensionFunctionType] kotlin.Function1<java.lang.StringBuilder, kotlin.Unit>): kotlin.String [inline] declared in kotlin.text.StringsKt' type=kotlin.String origin=null
                       builderAction: FUN_EXPR type=kotlin.Function1<java.lang.StringBuilder, kotlin.Unit> origin=LAMBDA
                         FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:java.lang.StringBuilder) returnType:kotlin.Unit
-                          $receiver: VALUE_PARAMETER name:<this> type:java.lang.StringBuilder
+                          $receiver: VALUE_PARAMETER name:$this$buildString type:java.lang.StringBuilder
                           BLOCK_BODY
                             BLOCK type=kotlin.Unit origin=FOR_LOOP
                               VAR FOR_LOOP_ITERATOR name:tmp_2 type:kotlin.collections.IntIterator [val]
@@ -85,7 +85,7 @@ FILE fqName:<root> fileName:/noSymbolForIntRangeIterator.kt
                                     CALL 'public final fun next (): kotlin.Int [operator] declared in kotlin.collections.IntIterator' type=kotlin.Int origin=FOR_LOOP_NEXT
                                       $this: GET_VAR 'val tmp_2: kotlin.collections.IntIterator [val] declared in <root>.test.localFunc.<anonymous>' type=kotlin.collections.IntIterator origin=null
                                   CALL 'public final fun appendLine (value: kotlin.String?): java.lang.StringBuilder [inline] declared in kotlin.text.StringsKt' type=java.lang.StringBuilder origin=null
-                                    $receiver: GET_VAR '<this>: java.lang.StringBuilder declared in <root>.test.localFunc.<anonymous>' type=java.lang.StringBuilder origin=null
+                                    $receiver: GET_VAR '$this$buildString: java.lang.StringBuilder declared in <root>.test.localFunc.<anonymous>' type=java.lang.StringBuilder origin=null
                                     value: STRING_CONCATENATION type=kotlin.String
                                       CALL 'public final fun times (other: kotlin.Int): kotlin.Int [operator] declared in kotlin.Int' type=kotlin.Int origin=MUL
                                         $this: GET_VAR 'val i: kotlin.Int [val] declared in <root>.test.localFunc' type=kotlin.Int origin=null
diff --git a/compiler/testData/debug/localVariables/suspend/mergeLvt.kt b/compiler/testData/debug/localVariables/suspend/mergeLvt.kt
index 4a0e4caf66e..6fef27fdd5b 100644
--- a/compiler/testData/debug/localVariables/suspend/mergeLvt.kt
+++ b/compiler/testData/debug/localVariables/suspend/mergeLvt.kt
@@ -41,7 +41,9 @@ suspend fun box() {
 // test.kt:16 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int, $this$extensionFun$iv$iv:AtomicInt=AtomicInt, $i$f$extensionFun:int=0:int
 // test.kt:20 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int
 // test.kt:21 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int, $i$a$-suspendCoroutineUninterceptedOrReturn-TestKt$suspendBar$2$iv:int=0:int
+// EXPECTATIONS CLASSIC_FRONTEND
 // test.kt:22 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int, $i$a$-suspendCoroutineUninterceptedOrReturn-TestKt$suspendBar$2$iv:int=0:int
+// EXPECTATIONS
 // test.kt:20 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int
 // test.kt:23 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null, $i$f$suspendBar:int=0:int
 // test.kt:26 box: $continuation:kotlin.coroutines.Continuation=TestKt$box$1, $result:java.lang.Object=null
diff --git a/compiler/testData/ir/irText/classes/initValInLambda.fir.ir.txt b/compiler/testData/ir/irText/classes/initValInLambda.fir.ir.txt
index 95468c94428..236ead7c1b4 100644
--- a/compiler/testData/ir/irText/classes/initValInLambda.fir.ir.txt
+++ b/compiler/testData/ir/irText/classes/initValInLambda.fir.ir.txt
@@ -22,7 +22,7 @@ FILE fqName:<root> fileName:/initValInLambda.kt
           $receiver: CONST Int type=kotlin.Int value=1
           block: FUN_EXPR type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:kotlin.Int) returnType:kotlin.Unit
-              $receiver: VALUE_PARAMETER name:<this> type:kotlin.Int
+              $receiver: VALUE_PARAMETER name:$this$run type:kotlin.Int
               BLOCK_BODY
                 SET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:x type:kotlin.Int visibility:private [final]' type=kotlin.Unit origin=null
                   receiver: GET_VAR '<this>: <root>.TestInitValInLambdaCalledOnce declared in <root>.TestInitValInLambdaCalledOnce' type=<root>.TestInitValInLambdaCalledOnce origin=null
diff --git a/compiler/testData/ir/irText/expressions/kt37570.fir.ir.txt b/compiler/testData/ir/irText/expressions/kt37570.fir.ir.txt
index d7d0151f215..b448ab99eb9 100644
--- a/compiler/testData/ir/irText/expressions/kt37570.fir.ir.txt
+++ b/compiler/testData/ir/irText/expressions/kt37570.fir.ir.txt
@@ -26,11 +26,11 @@ FILE fqName:<root> fileName:/kt37570.kt
             $receiver: CALL 'public final fun a (): kotlin.String declared in <root>' type=kotlin.String origin=null
             block: FUN_EXPR type=kotlin.Function1<kotlin.String, kotlin.Unit> origin=LAMBDA
               FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:kotlin.String) returnType:kotlin.Unit
-                $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
+                $receiver: VALUE_PARAMETER name:$this$apply type:kotlin.String
                 BLOCK_BODY
                   SET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:b type:kotlin.String visibility:private [final]' type=kotlin.Unit origin=null
                     receiver: GET_VAR '<this>: <root>.A declared in <root>.A' type=<root>.A origin=null
-                    value: GET_VAR '<this>: kotlin.String declared in <root>.A.<anonymous>' type=kotlin.String origin=null
+                    value: GET_VAR '$this$apply: kotlin.String declared in <root>.A.<anonymous>' type=kotlin.String origin=null
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
diff --git a/compiler/testData/ir/irText/expressions/kt37570.fir.kt.txt b/compiler/testData/ir/irText/expressions/kt37570.fir.kt.txt
index 76ba6c9c5c6..ed1901631b0 100644
--- a/compiler/testData/ir/irText/expressions/kt37570.fir.kt.txt
+++ b/compiler/testData/ir/irText/expressions/kt37570.fir.kt.txt
@@ -14,9 +14,10 @@ class A {
 
   init {
     a().apply<String>(block = local fun String.<anonymous>() {
-      <this>.#b = <this>
+      <this>.#b = $this$apply
     }
 ) /*~> Unit */
   }
 
 }
+
diff --git a/compiler/testData/ir/irText/expressions/kt47082.fir.ir.txt b/compiler/testData/ir/irText/expressions/kt47082.fir.ir.txt
index bed18a2041c..edeac2f00e0 100644
--- a/compiler/testData/ir/irText/expressions/kt47082.fir.ir.txt
+++ b/compiler/testData/ir/irText/expressions/kt47082.fir.ir.txt
@@ -74,14 +74,14 @@ FILE fqName:<root> fileName:/kt47082.kt
           <E>: R of <root>.foo
           block: FUN_EXPR type=kotlin.Function1<<root>.Derived<IrErrorType(null)>, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.Derived<IrErrorType(null)>) returnType:kotlin.Unit
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.Derived<IrErrorType(null)>
+              $receiver: VALUE_PARAMETER name:$this$produce type:<root>.Derived<IrErrorType(null)>
               BLOCK_BODY
                 TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                   CALL 'public final fun toChannel <E, C> (destination: C of <root>.toChannel): C of <root>.toChannel declared in <root>' type=<root>.Derived<IrErrorType(null)> origin=null
                     <E>: R of <root>.foo
                     <C>: <root>.Derived<IrErrorType(null)>
                     $receiver: GET_VAR 'r: <root>.Receiver<R of <root>.foo> declared in <root>.foo' type=<root>.Receiver<R of <root>.foo> origin=null
-                    destination: GET_VAR '<this>: <root>.Derived<IrErrorType(null)> declared in <root>.foo.<anonymous>' type=<root>.Derived<IrErrorType(null)> origin=null
+                    destination: GET_VAR '$this$produce: <root>.Derived<IrErrorType(null)> declared in <root>.foo.<anonymous>' type=<root>.Derived<IrErrorType(null)> origin=null
   FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.String
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
diff --git a/compiler/testData/ir/irText/expressions/kt47082.fir.kt.txt b/compiler/testData/ir/irText/expressions/kt47082.fir.kt.txt
index 587511dcc94..f3b306a7ae3 100644
--- a/compiler/testData/ir/irText/expressions/kt47082.fir.kt.txt
+++ b/compiler/testData/ir/irText/expressions/kt47082.fir.kt.txt
@@ -20,7 +20,7 @@ fun <E : Any?, C : Base<E>> Receiver<E>.toChannel(destination: C): C {
 
 fun <R : Any?> foo(r: Receiver<R>): R {
   return produce<R>(block = local fun Derived<ErrorType>.<anonymous>() {
-    r.toChannel<R, Derived<ErrorType>>(destination = <this>) /*~> Unit */
+    r.toChannel<R, Derived<ErrorType>>(destination = $this$produce) /*~> Unit */
   }
 )
 }
@@ -28,3 +28,4 @@ fun <R : Any?> foo(r: Receiver<R>): R {
 fun box(): String {
   return "OK"
 }
+
diff --git a/compiler/testData/ir/irText/firProblems/AllCandidates.fir.ir.txt b/compiler/testData/ir/irText/firProblems/AllCandidates.fir.ir.txt
index 6a07b6a4be9..765733157d8 100644
--- a/compiler/testData/ir/irText/firProblems/AllCandidates.fir.ir.txt
+++ b/compiler/testData/ir/irText/firProblems/AllCandidates.fir.ir.txt
@@ -61,10 +61,10 @@ FILE fqName:<root> fileName:/AllCandidates.kt
             <R>: @[FlexibleNullability] A of <root>.allCandidatesResult?
           block: FUN_EXPR type=kotlin.Function1<@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>?, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>?) returnType:kotlin.Unit
-              $receiver: VALUE_PARAMETER name:<this> type:@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>?
+              $receiver: VALUE_PARAMETER name:$this$apply type:@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>?
               BLOCK_BODY
                 CALL 'public open fun setAllCandidates (allCandidates: @[FlexibleNullability] kotlin.collections.Collection<@[FlexibleNullability] <root>.ResolvedCall<@[FlexibleNullability] D of <root>.OverloadResolutionResultsImpl?>?>?): kotlin.Unit declared in <root>.OverloadResolutionResultsImpl' type=kotlin.Unit origin=EQ
-                  $this: GET_VAR '<this>: @[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>? declared in <root>.allCandidatesResult.<anonymous>' type=@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>? origin=null
+                  $this: GET_VAR '$this$apply: @[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>? declared in <root>.allCandidatesResult.<anonymous>' type=@[FlexibleNullability] <root>.OverloadResolutionResultsImpl<@[FlexibleNullability] A of <root>.allCandidatesResult?>? origin=null
                   allCandidates: CALL 'public final fun map <T, R> (transform: kotlin.Function1<T of kotlin.collections.CollectionsKt.map, R of kotlin.collections.CollectionsKt.map>): kotlin.collections.List<R of kotlin.collections.CollectionsKt.map> [inline] declared in kotlin.collections.CollectionsKt' type=kotlin.collections.List<<root>.ResolvedCall<A of <root>.allCandidatesResult>> origin=null
                     <T>: <root>.MyCandidate
                     <R>: <root>.ResolvedCall<A of <root>.allCandidatesResult>
diff --git a/compiler/testData/ir/irText/firProblems/AllCandidates.fir.kt.txt b/compiler/testData/ir/irText/firProblems/AllCandidates.fir.kt.txt
index 5ac3b9c58f6..143474446d5 100644
--- a/compiler/testData/ir/irText/firProblems/AllCandidates.fir.kt.txt
+++ b/compiler/testData/ir/irText/firProblems/AllCandidates.fir.kt.txt
@@ -22,10 +22,11 @@ class MyCandidate {
 
 private fun <A : Any?> allCandidatesResult(allCandidates: Collection<MyCandidate>): @FlexibleNullability OverloadResolutionResultsImpl<@FlexibleNullability A?>? {
   return nameNotFound<@FlexibleNullability A?>().apply<@FlexibleNullability OverloadResolutionResultsImpl<@FlexibleNullability A?>?>(block = local fun @FlexibleNullability OverloadResolutionResultsImpl<@FlexibleNullability A?>?.<anonymous>() {
-    <this>.setAllCandidates(allCandidates = allCandidates.map<MyCandidate, ResolvedCall<A>>(transform = local fun <anonymous>(it: MyCandidate): ResolvedCall<A> {
+    $this$apply.setAllCandidates(allCandidates = allCandidates.map<MyCandidate, ResolvedCall<A>>(transform = local fun <anonymous>(it: MyCandidate): ResolvedCall<A> {
       return it.<get-resolvedCall>() as ResolvedCall<A>
     }
 ))
   }
 )
 }
+
diff --git a/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.ir.txt b/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.ir.txt
index 1eb1f603a16..2f960d9f8bd 100644
--- a/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.ir.txt
+++ b/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.ir.txt
@@ -622,31 +622,31 @@ FILE fqName:<root> fileName:/typeVariableAfterBuildMap.kt
             <V>: kotlin.Int
             builderAction: FUN_EXPR type=kotlin.Function1<kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int>, kotlin.Unit> origin=LAMBDA
               FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int>) returnType:kotlin.Unit
-                $receiver: VALUE_PARAMETER name:<this> type:kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int>
+                $receiver: VALUE_PARAMETER name:$this$buildMap type:kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int>
                 BLOCK_BODY
                   TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                     CALL 'public abstract fun put (key: K of kotlin.collections.MutableMap, value: V of kotlin.collections.MutableMap): V of kotlin.collections.MutableMap? declared in kotlin.collections.MutableMap' type=kotlin.Int? origin=null
-                      $this: GET_VAR '<this>: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
+                      $this: GET_VAR '$this$buildMap: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
                       key: GET_OBJECT 'CLASS OBJECT name:PrivateToThis modality:FINAL visibility:public superTypes:[<root>.Visibility]' type=<root>.Visibilities.PrivateToThis
                       value: CONST Int type=kotlin.Int value=0
                   TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                     CALL 'public abstract fun put (key: K of kotlin.collections.MutableMap, value: V of kotlin.collections.MutableMap): V of kotlin.collections.MutableMap? declared in kotlin.collections.MutableMap' type=kotlin.Int? origin=null
-                      $this: GET_VAR '<this>: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
+                      $this: GET_VAR '$this$buildMap: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
                       key: GET_OBJECT 'CLASS OBJECT name:Private modality:FINAL visibility:public superTypes:[<root>.Visibility]' type=<root>.Visibilities.Private
                       value: CONST Int type=kotlin.Int value=0
                   TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                     CALL 'public abstract fun put (key: K of kotlin.collections.MutableMap, value: V of kotlin.collections.MutableMap): V of kotlin.collections.MutableMap? declared in kotlin.collections.MutableMap' type=kotlin.Int? origin=null
-                      $this: GET_VAR '<this>: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
+                      $this: GET_VAR '$this$buildMap: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
                       key: GET_OBJECT 'CLASS OBJECT name:Internal modality:FINAL visibility:public superTypes:[<root>.Visibility]' type=<root>.Visibilities.Internal
                       value: CONST Int type=kotlin.Int value=1
                   TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                     CALL 'public abstract fun put (key: K of kotlin.collections.MutableMap, value: V of kotlin.collections.MutableMap): V of kotlin.collections.MutableMap? declared in kotlin.collections.MutableMap' type=kotlin.Int? origin=null
-                      $this: GET_VAR '<this>: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
+                      $this: GET_VAR '$this$buildMap: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
                       key: GET_OBJECT 'CLASS OBJECT name:Protected modality:FINAL visibility:public superTypes:[<root>.Visibility]' type=<root>.Visibilities.Protected
                       value: CONST Int type=kotlin.Int value=1
                   TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                     CALL 'public abstract fun put (key: K of kotlin.collections.MutableMap, value: V of kotlin.collections.MutableMap): V of kotlin.collections.MutableMap? declared in kotlin.collections.MutableMap' type=kotlin.Int? origin=null
-                      $this: GET_VAR '<this>: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
+                      $this: GET_VAR '$this$buildMap: kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> declared in <root>.Visibilities.ORDERED_VISIBILITIES.<anonymous>' type=kotlin.collections.MutableMap<<root>.Visibility, kotlin.Int> origin=null
                       key: GET_OBJECT 'CLASS OBJECT name:Public modality:FINAL visibility:public superTypes:[<root>.Visibility]' type=<root>.Visibilities.Public
                       value: CONST Int type=kotlin.Int value=2
       FUN DEFAULT_PROPERTY_ACCESSOR name:<get-ORDERED_VISIBILITIES> visibility:private modality:FINAL <> ($this:<root>.Visibilities) returnType:kotlin.collections.Map<<root>.Visibility, kotlin.Int>
diff --git a/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.kt.txt b/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.kt.txt
index 208bad8f60e..d6b34abc806 100644
--- a/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.kt.txt
+++ b/compiler/testData/ir/irText/firProblems/typeVariableAfterBuildMap.fir.kt.txt
@@ -163,13 +163,14 @@ object Visibilities {
 
   private val ORDERED_VISIBILITIES: Map<Visibility, Int>
     field = buildMap<Visibility, Int>(builderAction = local fun MutableMap<Visibility, Int>.<anonymous>() {
-      <this>.put(key = PrivateToThis, value = 0) /*~> Unit */
-      <this>.put(key = Private, value = 0) /*~> Unit */
-      <this>.put(key = Internal, value = 1) /*~> Unit */
-      <this>.put(key = Protected, value = 1) /*~> Unit */
-      <this>.put(key = Public, value = 2) /*~> Unit */
+      $this$buildMap.put(key = PrivateToThis, value = 0) /*~> Unit */
+      $this$buildMap.put(key = Private, value = 0) /*~> Unit */
+      $this$buildMap.put(key = Internal, value = 1) /*~> Unit */
+      $this$buildMap.put(key = Protected, value = 1) /*~> Unit */
+      $this$buildMap.put(key = Public, value = 2) /*~> Unit */
     }
 )
     private get
 
 }
+
diff --git a/compiler/testData/ir/irText/lambdas/destructuringInLambda.fir.ir.txt b/compiler/testData/ir/irText/lambdas/destructuringInLambda.fir.ir.txt
index 1f92d261a0c..dcdbccb9208 100644
--- a/compiler/testData/ir/irText/lambdas/destructuringInLambda.fir.ir.txt
+++ b/compiler/testData/ir/irText/lambdas/destructuringInLambda.fir.ir.txt
@@ -140,7 +140,7 @@ FILE fqName:<root> fileName:/destructuringInLambda.kt
       EXPRESSION_BODY
         FUN_EXPR type=kotlin.Function1<<root>.A, kotlin.Int> origin=LAMBDA
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (<destruct>:<root>.A) returnType:kotlin.Int
-            VALUE_PARAMETER name:<destruct> index:0 type:<root>.A
+            VALUE_PARAMETER DESTRUCTURED_OBJECT_PARAMETER name:<destruct> index:0 type:<root>.A
             BLOCK_BODY
               VAR name:y type:kotlin.Int [val]
                 CALL 'public final fun component2 (): kotlin.Int [operator] declared in <root>.A' type=kotlin.Int origin=COMPONENT_N(index=2)
diff --git a/compiler/testData/ir/irText/lambdas/extensionLambda.fir.ir.txt b/compiler/testData/ir/irText/lambdas/extensionLambda.fir.ir.txt
index 22aea224ecd..45026b02efd 100644
--- a/compiler/testData/ir/irText/lambdas/extensionLambda.fir.ir.txt
+++ b/compiler/testData/ir/irText/lambdas/extensionLambda.fir.ir.txt
@@ -8,8 +8,8 @@ FILE fqName:<root> fileName:/extensionLambda.kt
           $receiver: CONST String type=kotlin.String value="42"
           block: FUN_EXPR type=kotlin.Function1<kotlin.String, kotlin.Int> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:kotlin.String) returnType:kotlin.Int
-              $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
+              $receiver: VALUE_PARAMETER name:$this$run type:kotlin.String
               BLOCK_BODY
                 RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Int declared in <root>.test1'
                   CALL 'public open fun <get-length> (): kotlin.Int declared in kotlin.String' type=kotlin.Int origin=GET_PROPERTY
-                    $this: GET_VAR '<this>: kotlin.String declared in <root>.test1.<anonymous>' type=kotlin.String origin=null
+                    $this: GET_VAR '$this$run: kotlin.String declared in <root>.test1.<anonymous>' type=kotlin.String origin=null
diff --git a/compiler/testData/ir/irText/lambdas/extensionLambda.fir.kt.txt b/compiler/testData/ir/irText/lambdas/extensionLambda.fir.kt.txt
index 46b75238fa5..b353ca3f2b1 100644
--- a/compiler/testData/ir/irText/lambdas/extensionLambda.fir.kt.txt
+++ b/compiler/testData/ir/irText/lambdas/extensionLambda.fir.kt.txt
@@ -1,6 +1,7 @@
 fun test1(): Int {
   return "42".run<String, Int>(block = local fun String.<anonymous>(): Int {
-    return <this>.<get-length>()
+    return $this$run.<get-length>()
   }
 )
 }
+
diff --git a/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.ir.txt b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.ir.txt
new file mode 100644
index 00000000000..de94d045322
--- /dev/null
+++ b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.ir.txt
@@ -0,0 +1,15 @@
+FILE fqName:<root> fileName:/lambdaReturningUnit.kt
+  FUN name:flaf visibility:public modality:FINAL <> (block:kotlin.Function0<kotlin.Any?>) returnType:kotlin.Unit [inline]
+    VALUE_PARAMETER name:block index:0 type:kotlin.Function0<kotlin.Any?>
+    BLOCK_BODY
+      TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
+        CALL 'public abstract fun invoke (): R of kotlin.Function0 [operator] declared in kotlin.Function0' type=kotlin.Any? origin=INVOKE
+          $this: GET_VAR 'block: kotlin.Function0<kotlin.Any?> declared in <root>.flaf' type=kotlin.Function0<kotlin.Any?> origin=VARIABLE_AS_FUNCTION
+  FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.Unit [suspend]
+    BLOCK_BODY
+      CALL 'public final fun flaf (block: kotlin.Function0<kotlin.Any?>): kotlin.Unit [inline] declared in <root>' type=kotlin.Unit origin=null
+        block: FUN_EXPR type=kotlin.Function0<kotlin.Any?> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Any?
+            BLOCK_BODY
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Any? declared in <root>.box'
+                GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
diff --git a/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.kt.txt b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.kt.txt
new file mode 100644
index 00000000000..7f77b344a30
--- /dev/null
+++ b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.fir.kt.txt
@@ -0,0 +1,10 @@
+inline fun flaf(block: Function0<Any?>) {
+  block.invoke() /*~> Unit */
+}
+
+suspend fun box() {
+  flaf(block = local fun <anonymous>(): Any? {
+    return Unit
+  }
+)
+}
diff --git a/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.ir.txt b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.ir.txt
new file mode 100644
index 00000000000..f5440d0b590
--- /dev/null
+++ b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.ir.txt
@@ -0,0 +1,14 @@
+FILE fqName:<root> fileName:/lambdaReturningUnit.kt
+  FUN name:flaf visibility:public modality:FINAL <> (block:kotlin.Function0<kotlin.Any?>) returnType:kotlin.Unit [inline]
+    VALUE_PARAMETER name:block index:0 type:kotlin.Function0<kotlin.Any?>
+    BLOCK_BODY
+      TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
+        CALL 'public abstract fun invoke (): R of kotlin.Function0 [operator] declared in kotlin.Function0' type=kotlin.Any? origin=INVOKE
+          $this: GET_VAR 'block: kotlin.Function0<kotlin.Any?> declared in <root>.flaf' type=kotlin.Function0<kotlin.Any?> origin=VARIABLE_AS_FUNCTION
+  FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.Unit [suspend]
+    BLOCK_BODY
+      CALL 'public final fun flaf (block: kotlin.Function0<kotlin.Any?>): kotlin.Unit [inline] declared in <root>' type=kotlin.Unit origin=null
+        block: FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
+            BLOCK_BODY
+              GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
diff --git a/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt
new file mode 100644
index 00000000000..fefa6a759ec
--- /dev/null
+++ b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt
@@ -0,0 +1,12 @@
+// With FIR the type of the lambda in box is () -> Any?
+// With old frontend the type of the lambda is () -> Unit
+
+inline fun flaf(block: () -> Any?) {
+    block()
+}
+
+suspend fun box() {
+    flaf {
+        Unit
+    }
+}
diff --git a/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt.txt b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt.txt
new file mode 100644
index 00000000000..0ba7d56ae4d
--- /dev/null
+++ b/compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt.txt
@@ -0,0 +1,11 @@
+inline fun flaf(block: Function0<Any?>) {
+  block.invoke() /*~> Unit */
+}
+
+suspend fun box() {
+  flaf(block = local fun <anonymous>() {
+    Unit
+  }
+)
+}
+
diff --git a/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.ir.txt b/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.ir.txt
index 382de868b94..1a04f896442 100644
--- a/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.ir.txt
+++ b/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.ir.txt
@@ -92,7 +92,7 @@ FILE fqName:<root> fileName:/multipleImplicitReceivers.kt
           receiver: GET_OBJECT 'CLASS OBJECT name:A modality:FINAL visibility:public superTypes:[kotlin.Any]' type=<root>.A
           block: FUN_EXPR type=kotlin.Function1<<root>.A, kotlin.Int> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.A) returnType:kotlin.Int
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.A
+              $receiver: VALUE_PARAMETER name:$this$with type:<root>.A
               BLOCK_BODY
                 RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Int declared in <root>.test'
                   CALL 'public final fun with <T, R> (receiver: T of kotlin.StandardKt.with, block: @[ExtensionFunctionType] kotlin.Function1<T of kotlin.StandardKt.with, R of kotlin.StandardKt.with>): R of kotlin.StandardKt.with [inline] declared in kotlin.StandardKt' type=kotlin.Int origin=null
@@ -101,7 +101,7 @@ FILE fqName:<root> fileName:/multipleImplicitReceivers.kt
                     receiver: GET_VAR 'fooImpl: <root>.IFoo declared in <root>.test' type=<root>.IFoo origin=null
                     block: FUN_EXPR type=kotlin.Function1<<root>.IFoo, kotlin.Int> origin=LAMBDA
                       FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.IFoo) returnType:kotlin.Int
-                        $receiver: VALUE_PARAMETER name:<this> type:<root>.IFoo
+                        $receiver: VALUE_PARAMETER name:$this$with type:<root>.IFoo
                         BLOCK_BODY
                           RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Int declared in <root>.test.<anonymous>'
                             CALL 'public final fun with <T, R> (receiver: T of kotlin.StandardKt.with, block: @[ExtensionFunctionType] kotlin.Function1<T of kotlin.StandardKt.with, R of kotlin.StandardKt.with>): R of kotlin.StandardKt.with [inline] declared in kotlin.StandardKt' type=kotlin.Int origin=null
@@ -110,11 +110,11 @@ FILE fqName:<root> fileName:/multipleImplicitReceivers.kt
                               receiver: GET_VAR 'invokeImpl: <root>.IInvoke declared in <root>.test' type=<root>.IInvoke origin=null
                               block: FUN_EXPR type=kotlin.Function1<<root>.IInvoke, kotlin.Int> origin=LAMBDA
                                 FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.IInvoke) returnType:kotlin.Int
-                                  $receiver: VALUE_PARAMETER name:<this> type:<root>.IInvoke
+                                  $receiver: VALUE_PARAMETER name:$this$with type:<root>.IInvoke
                                   BLOCK_BODY
                                     RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Int declared in <root>.test.<anonymous>.<anonymous>'
                                       CALL 'public open fun invoke (): kotlin.Int [operator] declared in <root>.IInvoke' type=kotlin.Int origin=null
-                                        $this: GET_VAR '<this>: <root>.IInvoke declared in <root>.test.<anonymous>.<anonymous>.<anonymous>' type=<root>.IInvoke origin=null
+                                        $this: GET_VAR '$this$with: <root>.IInvoke declared in <root>.test.<anonymous>.<anonymous>.<anonymous>' type=<root>.IInvoke origin=null
                                         $receiver: CALL 'public open fun <get-foo> (): <root>.B declared in <root>.IFoo' type=<root>.B origin=GET_PROPERTY
-                                          $this: GET_VAR '<this>: <root>.IFoo declared in <root>.test.<anonymous>.<anonymous>' type=<root>.IFoo origin=null
-                                          $receiver: GET_VAR '<this>: <root>.A declared in <root>.test.<anonymous>' type=<root>.A origin=null
+                                          $this: GET_VAR '$this$with: <root>.IFoo declared in <root>.test.<anonymous>.<anonymous>' type=<root>.IFoo origin=null
+                                          $receiver: GET_VAR '$this$with: <root>.A declared in <root>.test.<anonymous>' type=<root>.A origin=null
diff --git a/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.kt.txt b/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.kt.txt
index ebb433fa9a2..c44b81ee74d 100644
--- a/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.kt.txt
+++ b/compiler/testData/ir/irText/lambdas/multipleImplicitReceivers.fir.kt.txt
@@ -35,7 +35,7 @@ fun test(fooImpl: IFoo, invokeImpl: IInvoke) {
   with<A, Int>(receiver = A, block = local fun A.<anonymous>(): Int {
     return with<IFoo, Int>(receiver = fooImpl, block = local fun IFoo.<anonymous>(): Int {
       return with<IInvoke, Int>(receiver = invokeImpl, block = local fun IInvoke.<anonymous>(): Int {
-        return (<this>, (<this>, <this>).<get-foo>()).invoke()
+        return ($this$with, ($this$with, $this$with).<get-foo>()).invoke()
       }
 )
     }
@@ -43,3 +43,4 @@ fun test(fooImpl: IFoo, invokeImpl: IInvoke) {
   }
 ) /*~> Unit */
 }
+
diff --git a/compiler/testData/ir/irText/stubs/builtinMap.fir.ir.txt b/compiler/testData/ir/irText/stubs/builtinMap.fir.ir.txt
index c081da912c4..d54490ee6a5 100644
--- a/compiler/testData/ir/irText/stubs/builtinMap.fir.ir.txt
+++ b/compiler/testData/ir/irText/stubs/builtinMap.fir.ir.txt
@@ -24,11 +24,11 @@ FILE fqName:<root> fileName:/builtinMap.kt
                 p0: GET_VAR '<this>: kotlin.collections.Map<out K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.collections.Map<out K1 of <root>.plus, V1 of <root>.plus> origin=null
               block: FUN_EXPR type=kotlin.Function1<java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?>, kotlin.Unit> origin=LAMBDA
                 FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?>) returnType:kotlin.Unit
-                  $receiver: VALUE_PARAMETER name:<this> type:java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?>
+                  $receiver: VALUE_PARAMETER name:$this$apply type:java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?>
                   BLOCK_BODY
                     TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
                       CALL 'public open fun put (p0: @[FlexibleNullability] K of java.util.LinkedHashMap?, p1: @[FlexibleNullability] V of java.util.LinkedHashMap?): V of java.util.LinkedHashMap? [fake_override] declared in java.util.LinkedHashMap' type=V1 of <root>.plus? origin=null
-                        $this: GET_VAR '<this>: java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?> declared in <root>.plus.<anonymous>' type=java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?> origin=null
+                        $this: GET_VAR '$this$apply: java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?> declared in <root>.plus.<anonymous>' type=java.util.LinkedHashMap<@[FlexibleNullability] K1 of <root>.plus?, @[FlexibleNullability] V1 of <root>.plus?> origin=null
                         p0: CALL 'public final fun <get-first> (): A of kotlin.Pair declared in kotlin.Pair' type=K1 of <root>.plus origin=GET_PROPERTY
                           $this: GET_VAR 'pair: kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> origin=null
                         p1: CALL 'public final fun <get-second> (): B of kotlin.Pair declared in kotlin.Pair' type=V1 of <root>.plus origin=GET_PROPERTY
diff --git a/compiler/testData/ir/irText/stubs/builtinMap.fir.kt.txt b/compiler/testData/ir/irText/stubs/builtinMap.fir.kt.txt
index a43473a82d0..8c96621b011 100644
--- a/compiler/testData/ir/irText/stubs/builtinMap.fir.kt.txt
+++ b/compiler/testData/ir/irText/stubs/builtinMap.fir.kt.txt
@@ -2,8 +2,9 @@ fun <K1 : Any?, V1 : Any?> Map<out K1, V1>.plus(pair: Pair<K1, V1>): Map<K1, V1>
   return when {
     <this>.isEmpty() -> mapOf<K1, V1>(pair = pair)
     else -> LinkedHashMap<@FlexibleNullability K1?, @FlexibleNullability V1?>(p0 = <this>).apply<LinkedHashMap<@FlexibleNullability K1?, @FlexibleNullability V1?>>(block = local fun LinkedHashMap<@FlexibleNullability K1?, @FlexibleNullability V1?>.<anonymous>() {
-      <this>.put(p0 = pair.<get-first>(), p1 = pair.<get-second>()) /*~> Unit */
+      $this$apply.put(p0 = pair.<get-first>(), p1 = pair.<get-second>()) /*~> Unit */
     }
 )
   }
 }
+
diff --git a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.ir.txt b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.ir.txt
index 7798f101e28..a743ccd9e03 100644
--- a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.ir.txt
+++ b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.ir.txt
@@ -12,19 +12,19 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
           <T>: R of <root>.scopedFlow
           block: FUN_EXPR type=kotlin.coroutines.SuspendFunction1<<root>.FlowCollector<R of <root>.scopedFlow>, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.FlowCollector<R of <root>.scopedFlow>) returnType:kotlin.Unit [suspend]
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.FlowCollector<R of <root>.scopedFlow>
+              $receiver: VALUE_PARAMETER name:$this$flow type:<root>.FlowCollector<R of <root>.scopedFlow>
               BLOCK_BODY
                 VAR name:collector type:<root>.FlowCollector<R of <root>.scopedFlow> [val]
-                  GET_VAR '<this>: <root>.FlowCollector<R of <root>.scopedFlow> declared in <root>.scopedFlow.<anonymous>' type=<root>.FlowCollector<R of <root>.scopedFlow> origin=null
+                  GET_VAR '$this$flow: <root>.FlowCollector<R of <root>.scopedFlow> declared in <root>.scopedFlow.<anonymous>' type=<root>.FlowCollector<R of <root>.scopedFlow> origin=null
                 CALL 'public final fun flowScope <R> (block: @[ExtensionFunctionType] kotlin.coroutines.SuspendFunction1<<root>.CoroutineScope, R of <root>.flowScope>): R of <root>.flowScope [suspend] declared in <root>' type=kotlin.Unit origin=null
                   <R>: kotlin.Unit
                   block: FUN_EXPR type=kotlin.coroutines.SuspendFunction1<<root>.CoroutineScope, kotlin.Unit> origin=LAMBDA
                     FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.CoroutineScope) returnType:kotlin.Unit [suspend]
-                      $receiver: VALUE_PARAMETER name:<this> type:<root>.CoroutineScope
+                      $receiver: VALUE_PARAMETER name:$this$flowScope type:<root>.CoroutineScope
                       BLOCK_BODY
                         CALL 'public abstract fun invoke (p1: P1 of kotlin.coroutines.SuspendFunction2, p2: P2 of kotlin.coroutines.SuspendFunction2): R of kotlin.coroutines.SuspendFunction2 [suspend,operator] declared in kotlin.coroutines.SuspendFunction2' type=kotlin.Unit origin=null
                           $this: GET_VAR 'block: @[ExtensionFunctionType] kotlin.coroutines.SuspendFunction2<<root>.CoroutineScope, <root>.FlowCollector<R of <root>.scopedFlow>, kotlin.Unit> declared in <root>.scopedFlow' type=@[ExtensionFunctionType] kotlin.coroutines.SuspendFunction2<<root>.CoroutineScope, <root>.FlowCollector<R of <root>.scopedFlow>, kotlin.Unit> origin=VARIABLE_AS_FUNCTION
-                          p1: GET_VAR '<this>: <root>.CoroutineScope declared in <root>.scopedFlow.<anonymous>.<anonymous>' type=<root>.CoroutineScope origin=null
+                          p1: GET_VAR '$this$flowScope: <root>.CoroutineScope declared in <root>.scopedFlow.<anonymous>.<anonymous>' type=<root>.CoroutineScope origin=null
                           p2: GET_VAR 'val collector: <root>.FlowCollector<R of <root>.scopedFlow> [val] declared in <root>.scopedFlow.<anonymous>' type=<root>.FlowCollector<R of <root>.scopedFlow> origin=null
   FUN name:onCompletion visibility:public modality:FINAL <T> ($receiver:<root>.Flow<T of <root>.onCompletion>, action:@[ExtensionFunctionType] kotlin.coroutines.SuspendFunction2<<root>.FlowCollector<T of <root>.onCompletion>, @[ParameterName(name = 'cause')] kotlin.Throwable?, kotlin.Unit>) returnType:<root>.Flow<T of <root>.onCompletion>
     TYPE_PARAMETER name:T index:0 variance: superTypes:[kotlin.Any?]
@@ -36,12 +36,12 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
           <T>: T of <root>.onCompletion
           block: FUN_EXPR type=kotlin.coroutines.SuspendFunction1<<root>.FlowCollector<T of <root>.onCompletion>, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.FlowCollector<T of <root>.onCompletion>) returnType:kotlin.Unit [suspend]
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.FlowCollector<T of <root>.onCompletion>
+              $receiver: VALUE_PARAMETER name:$this$unsafeFlow type:<root>.FlowCollector<T of <root>.onCompletion>
               BLOCK_BODY
                 VAR name:safeCollector type:<root>.SafeCollector<T of <root>.onCompletion> [val]
                   CONSTRUCTOR_CALL 'public constructor <init> (collector: <root>.FlowCollector<T of <root>.SafeCollector>) [primary] declared in <root>.SafeCollector' type=<root>.SafeCollector<T of <root>.onCompletion> origin=null
                     <class: T>: T of <root>.onCompletion
-                    collector: GET_VAR '<this>: <root>.FlowCollector<T of <root>.onCompletion> declared in <root>.onCompletion.<anonymous>' type=<root>.FlowCollector<T of <root>.onCompletion> origin=null
+                    collector: GET_VAR '$this$unsafeFlow: <root>.FlowCollector<T of <root>.onCompletion> declared in <root>.onCompletion.<anonymous>' type=<root>.FlowCollector<T of <root>.onCompletion> origin=null
                 CALL 'public final fun invokeSafely <T> (action: @[ExtensionFunctionType] kotlin.coroutines.SuspendFunction2<<root>.FlowCollector<T of <root>.invokeSafely>, @[ParameterName(name = 'cause')] kotlin.Throwable?, kotlin.Unit>): kotlin.Unit [suspend] declared in <root>' type=kotlin.Unit origin=null
                   <T>: T of <root>.onCompletion
                   $receiver: GET_VAR 'val safeCollector: <root>.SafeCollector<T of <root>.onCompletion> [val] declared in <root>.onCompletion.<anonymous>' type=<root>.SafeCollector<T of <root>.onCompletion> origin=null
@@ -74,7 +74,7 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
           $receiver: GET_VAR '<this>: <root>.Flow<T of <root>.onCompletion> declared in <root>.onCompletion' type=<root>.Flow<T of <root>.onCompletion> origin=null
           action: FUN_EXPR type=kotlin.coroutines.SuspendFunction2<<root>.FlowCollector<T of <root>.onCompletion>, @[ParameterName(name = 'cause')] kotlin.Throwable?, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.FlowCollector<T of <root>.onCompletion>, it:@[ParameterName(name = 'cause')] kotlin.Throwable?) returnType:kotlin.Unit [suspend]
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.FlowCollector<T of <root>.onCompletion>
+              $receiver: VALUE_PARAMETER name:$this$onCompletion type:<root>.FlowCollector<T of <root>.onCompletion>
               VALUE_PARAMETER name:it index:0 type:@[ParameterName(name = 'cause')] kotlin.Throwable?
               BLOCK_BODY
                 CALL 'public abstract fun invoke (p1: P1 of kotlin.coroutines.SuspendFunction1): R of kotlin.coroutines.SuspendFunction1 [suspend,operator] declared in kotlin.coroutines.SuspendFunction1' type=kotlin.Unit origin=null
@@ -90,12 +90,12 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
           $receiver: GET_VAR '<this>: <root>.CoroutineScope declared in <root>.asFairChannel' type=<root>.CoroutineScope origin=null
           block: FUN_EXPR type=kotlin.coroutines.SuspendFunction1<<root>.ProducerScope<kotlin.Any>, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.ProducerScope<kotlin.Any>) returnType:kotlin.Unit [suspend]
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.ProducerScope<kotlin.Any>
+              $receiver: VALUE_PARAMETER name:$this$produce type:<root>.ProducerScope<kotlin.Any>
               BLOCK_BODY
                 VAR name:channel type:<root>.ChannelCoroutine<kotlin.Any> [val]
                   TYPE_OP type=<root>.ChannelCoroutine<kotlin.Any> origin=CAST typeOperand=<root>.ChannelCoroutine<kotlin.Any>
                     CALL 'public abstract fun <get-channel> (): <root>.SendChannel<E of <root>.ProducerScope> declared in <root>.ProducerScope' type=<root>.SendChannel<kotlin.Nothing> origin=GET_PROPERTY
-                      $this: GET_VAR '<this>: <root>.ProducerScope<kotlin.Any> declared in <root>.asFairChannel.<anonymous>' type=<root>.ProducerScope<kotlin.Nothing> origin=null
+                      $this: GET_VAR '$this$produce: <root>.ProducerScope<kotlin.Any> declared in <root>.asFairChannel.<anonymous>' type=<root>.ProducerScope<kotlin.Nothing> origin=null
                 CALL 'public final fun collect <T> (action: kotlin.coroutines.SuspendFunction1<@[ParameterName(name = 'value')] T of <root>.collect, kotlin.Unit>): kotlin.Unit [inline,suspend] declared in <root>' type=kotlin.Unit origin=null
                   <T>: kotlin.Any?
                   $receiver: GET_VAR 'flow: <root>.Flow<*> declared in <root>.asFairChannel' type=<root>.Flow<*> origin=null
@@ -128,7 +128,7 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
           $receiver: GET_VAR '<this>: <root>.CoroutineScope declared in <root>.asChannel' type=<root>.CoroutineScope origin=null
           block: FUN_EXPR type=kotlin.coroutines.SuspendFunction1<<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any>, kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any>) returnType:kotlin.Unit [suspend]
-              $receiver: VALUE_PARAMETER name:<this> type:<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any>
+              $receiver: VALUE_PARAMETER name:$this$produce type:<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any>
               BLOCK_BODY
                 CALL 'public final fun collect <T> (action: kotlin.coroutines.SuspendFunction1<@[ParameterName(name = 'value')] T of <root>.collect, kotlin.Unit>): kotlin.Unit [inline,suspend] declared in <root>' type=kotlin.Unit origin=null
                   <T>: kotlin.Any?
@@ -140,7 +140,7 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
                         RETURN type=kotlin.Nothing from='local final fun <anonymous> (value: @[ParameterName(name = 'value')] kotlin.Any?): kotlin.Unit [suspend] declared in <root>.asChannel.<anonymous>'
                           CALL 'public abstract fun send (e: E of <root>.SendChannel): kotlin.Unit [suspend] declared in <root>.SendChannel' type=kotlin.Unit origin=null
                             $this: CALL 'public abstract fun <get-channel> (): <root>.SendChannel<E of <root>.ProducerScope> declared in <root>.ProducerScope' type=<root>.SendChannel<@[ParameterName(name = 'value')] kotlin.Any> origin=GET_PROPERTY
-                              $this: GET_VAR '<this>: <root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any> declared in <root>.asChannel.<anonymous>' type=<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any> origin=null
+                              $this: GET_VAR '$this$produce: <root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any> declared in <root>.asChannel.<anonymous>' type=<root>.ProducerScope<@[ParameterName(name = 'value')] kotlin.Any> origin=null
                             e: BLOCK type=@[ParameterName(name = 'value')] kotlin.Any origin=ELVIS
                               VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:@[ParameterName(name = 'value')] kotlin.Any? [val]
                                 GET_VAR 'value: @[ParameterName(name = 'value')] kotlin.Any? declared in <root>.asChannel.<anonymous>.<anonymous>' type=@[ParameterName(name = 'value')] kotlin.Any? origin=null
diff --git a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.kt.txt b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.kt.txt
index b5f21f95346..96ea9b1f064 100644
--- a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.kt.txt
+++ b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.kt.txt
@@ -1,9 +1,9 @@
 @OptIn(markerClass = [ExperimentalTypeInference::class])
 fun <R : Any?> scopedFlow(@BuilderInference block: @ExtensionFunctionType SuspendFunction2<CoroutineScope, FlowCollector<R>, Unit>): Flow<R> {
   return flow<R>(block = local suspend fun FlowCollector<R>.<anonymous>() {
-    val collector: FlowCollector<R> = <this>
+    val collector: FlowCollector<R> = $this$flow
     flowScope<Unit>(block = local suspend fun CoroutineScope.<anonymous>() {
-      block.invoke(p1 = <this>, p2 = collector)
+      block.invoke(p1 = $this$flowScope, p2 = collector)
     }
 )
   }
@@ -12,7 +12,7 @@ fun <R : Any?> scopedFlow(@BuilderInference block: @ExtensionFunctionType Suspen
 
 fun <T : Any?> Flow<T>.onCompletion(action: @ExtensionFunctionType SuspendFunction2<FlowCollector<T>, @ParameterName(name = "cause") Throwable?, Unit>): Flow<T> {
   return unsafeFlow<T>(block = local suspend fun FlowCollector<T>.<anonymous>() {
-    val safeCollector: SafeCollector<T> = SafeCollector<T>(collector = <this>)
+    val safeCollector: SafeCollector<T> = SafeCollector<T>(collector = $this$unsafeFlow)
     safeCollector.invokeSafely<T>(action = action)
   }
 )
@@ -36,7 +36,7 @@ fun <T : Any?> Flow<T>.onCompletion(action: SuspendFunction1<@ParameterName(name
 
 private fun CoroutineScope.asFairChannel(flow: Flow<*>): ReceiveChannel<Any> {
   return <this>.produce<Any>(block = local suspend fun ProducerScope<Any>.<anonymous>() {
-    val channel: ChannelCoroutine<Any> = <this>.<get-channel>() as ChannelCoroutine<Any>
+    val channel: ChannelCoroutine<Any> = $this$produce.<get-channel>() as ChannelCoroutine<Any>
     flow.collect<Any?>(action = local suspend fun <anonymous>(value: @ParameterName(name = "value") Any?) {
       return channel.sendFair(element = { // BLOCK
         val <elvis>: @ParameterName(name = "value") Any? = value
@@ -54,7 +54,7 @@ private fun CoroutineScope.asFairChannel(flow: Flow<*>): ReceiveChannel<Any> {
 private fun CoroutineScope.asChannel(flow: Flow<*>): ReceiveChannel<Any> {
   return <this>.produce<@ParameterName(name = "value") Any>(block = local suspend fun ProducerScope<@ParameterName(name = "value") Any>.<anonymous>() {
     flow.collect<Any?>(action = local suspend fun <anonymous>(value: @ParameterName(name = "value") Any?) {
-      return <this>.<get-channel>().send(e = { // BLOCK
+      return $this$produce.<get-channel>().send(e = { // BLOCK
         val <elvis>: @ParameterName(name = "value") Any? = value
         when {
           EQEQ(arg0 = <elvis>, arg1 = null) -> Any()
@@ -141,3 +141,4 @@ interface SendChannel<in E : Any?> {
   abstract suspend fun send(e: E)
 
 }
+
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ir/IrTextTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ir/IrTextTestGenerated.java
index 21324fc91b2..51681a53842 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ir/IrTextTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ir/IrTextTestGenerated.java
@@ -2462,6 +2462,12 @@ public class IrTextTestGenerated extends AbstractIrTextTest {
             runTest("compiler/testData/ir/irText/lambdas/justLambda.kt");
         }
 
+        @Test
+        @TestMetadata("lambdaReturningUnit.kt")
+        public void testLambdaReturningUnit() throws Exception {
+            runTest("compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt");
+        }
+
         @Test
         @TestMetadata("localFunction.kt")
         public void testLocalFunction() throws Exception {
diff --git a/compiler/tests-common-new/tests/org/jetbrains/kotlin/test/backend/handlers/DebugRunner.kt b/compiler/tests-common-new/tests/org/jetbrains/kotlin/test/backend/handlers/DebugRunner.kt
index 6d7fcf661a9..bbbb8fc1392 100644
--- a/compiler/tests-common-new/tests/org/jetbrains/kotlin/test/backend/handlers/DebugRunner.kt
+++ b/compiler/tests-common-new/tests/org/jetbrains/kotlin/test/backend/handlers/DebugRunner.kt
@@ -11,6 +11,8 @@ import com.sun.jdi.request.EventRequest.SUSPEND_ALL
 import com.sun.jdi.request.StepRequest
 import com.sun.tools.jdi.SocketAttachingConnector
 import org.jetbrains.kotlin.test.TargetBackend
+import org.jetbrains.kotlin.test.model.FrontendKind
+import org.jetbrains.kotlin.test.model.FrontendKinds
 import org.jetbrains.kotlin.test.model.TestModule
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.assertEqualsToFile
 import org.jetbrains.kotlin.test.services.TestServices
@@ -27,12 +29,15 @@ abstract class DebugRunner(testServices: TestServices) : JvmBoxRunner(testServic
         const val FORCE_STEP_INTO_MARKER = "// FORCE_STEP_INTO"
         const val JVM_EXPECTATIONS_MARKER = "$EXPECTATIONS_MARKER JVM"
         const val JVM_IR_EXPECTATIONS_MARKER = "$EXPECTATIONS_MARKER JVM_IR"
+        const val CLASSIC_FRONTEND_EXPECTATIONS_MARKER = "$EXPECTATIONS_MARKER CLASSIC_FRONTEND"
+        const val FIR_EXPECTATIONS_MARKER = "$EXPECTATIONS_MARKER FIR"
 
         val BOX_MAIN_FILE_CLASS_NAME = BOX_MAIN_FILE_NAME.replace(".kt", "Kt")
     }
 
     private var wholeFile = File("")
     private var backend = TargetBackend.JVM
+    private var frontend: FrontendKind<*> = FrontendKinds.ClassicFrontend
 
     abstract fun storeStep(loggedItems: ArrayList<LoggedData>, event: Event)
 
@@ -42,8 +47,9 @@ abstract class DebugRunner(testServices: TestServices) : JvmBoxRunner(testServic
         classPath: List<URL>,
         mainClassAndArguments: List<String>
     ): Process {
-        // Extract target backend and the full test file used to extract test expectations.
+        // Extract target backend, frontend, and the full test file used to extract test expectations.
         backend = module.targetBackend ?: backend
+        frontend = module.frontendKind
         wholeFile = module.files.single { it.name == "test.kt" }.originalFile
 
         // Setup the java process to suspend waiting for debugging connection on a free port.
@@ -187,6 +193,7 @@ abstract class DebugRunner(testServices: TestServices) : JvmBoxRunner(testServic
         }
 
         var currentBackend = TargetBackend.ANY
+        var currentFrontend = frontend
         for (line in lineIterator) {
             if (line.isEmpty()) {
                 actual.add(line)
@@ -198,11 +205,22 @@ abstract class DebugRunner(testServices: TestServices) : JvmBoxRunner(testServic
                     EXPECTATIONS_MARKER -> TargetBackend.ANY
                     JVM_EXPECTATIONS_MARKER -> TargetBackend.JVM
                     JVM_IR_EXPECTATIONS_MARKER -> TargetBackend.JVM_IR
+                    CLASSIC_FRONTEND_EXPECTATIONS_MARKER -> currentBackend
+                    FIR_EXPECTATIONS_MARKER -> currentBackend
+                    else -> error("Expected JVM backend: $line")
+                }
+                currentFrontend = when (line) {
+                    EXPECTATIONS_MARKER -> frontend
+                    JVM_EXPECTATIONS_MARKER -> currentFrontend
+                    JVM_IR_EXPECTATIONS_MARKER -> currentFrontend
+                    CLASSIC_FRONTEND_EXPECTATIONS_MARKER -> FrontendKinds.ClassicFrontend
+                    FIR_EXPECTATIONS_MARKER -> FrontendKinds.FIR
                     else -> error("Expected JVM backend: $line")
                 }
                 continue
             }
-            if (currentBackend == TargetBackend.ANY || currentBackend == backend) {
+            if ((currentBackend == TargetBackend.ANY || currentBackend == backend) &&
+                currentFrontend == frontend) {
                 if (actualLineNumbersIterator.hasNext()) {
                     actual.add(actualLineNumbersIterator.next())
                 }
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/ir/KlibTextTestCaseGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/ir/KlibTextTestCaseGenerated.java
index 09afbabd6ff..beaa84139e7 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/ir/KlibTextTestCaseGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/ir/KlibTextTestCaseGenerated.java
@@ -1831,6 +1831,11 @@ public class KlibTextTestCaseGenerated extends AbstractKlibTextTestCase {
             runTest("compiler/testData/ir/irText/lambdas/justLambda.kt");
         }
 
+        @TestMetadata("lambdaReturningUnit.kt")
+        public void testLambdaReturningUnit() throws Exception {
+            runTest("compiler/testData/ir/irText/lambdas/lambdaReturningUnit.kt");
+        }
+
         @TestMetadata("localFunction.kt")
         public void testLocalFunction() throws Exception {
             runTest("compiler/testData/ir/irText/lambdas/localFunction.kt");