diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Arguments.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Arguments.kt
index 9c62316d0e6..adcb10f28d2 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Arguments.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/Arguments.kt
@@ -402,7 +402,7 @@ fun FirExpression.isFunctional(
             if (coneType.isBuiltinFunctionalType(session)) {
                 return true
             }
-            val classLikeExpectedFunctionType = expectedFunctionType as? ConeClassLikeType
+            val classLikeExpectedFunctionType = expectedFunctionType?.lowerBoundIfFlexible() as? ConeClassLikeType
             if (classLikeExpectedFunctionType == null || coneType is ConeIntegerLiteralType) {
                 return false
             }
diff --git a/compiler/testData/codegen/box/sam/passSubtypeOfFunctionSamConversion.kt b/compiler/testData/codegen/box/sam/passSubtypeOfFunctionSamConversion.kt
index d2b87472604..11948e9ce26 100644
--- a/compiler/testData/codegen/box/sam/passSubtypeOfFunctionSamConversion.kt
+++ b/compiler/testData/codegen/box/sam/passSubtypeOfFunctionSamConversion.kt
@@ -1,5 +1,4 @@
 // TARGET_BACKEND: JVM
-// IGNORE_BACKEND_FIR: JVM_IR
 
 // FILE: a.kt
 
diff --git a/compiler/testData/diagnostics/tests/j+k/sam/recursiveSamsAndInvoke.kt b/compiler/testData/diagnostics/tests/j+k/sam/recursiveSamsAndInvoke.kt
index f4d975f42ef..37fcf10fcc9 100644
--- a/compiler/testData/diagnostics/tests/j+k/sam/recursiveSamsAndInvoke.kt
+++ b/compiler/testData/diagnostics/tests/j+k/sam/recursiveSamsAndInvoke.kt
@@ -16,7 +16,7 @@ public interface MyListener<F extends MyFuture<?>>  {
 typealias Handler = (cause: Throwable?) -> Unit
 
 fun <T> MyFuture<T>.setup() {
-    addListener(ListenerImpl<T, MyFuture<T>>())
+    <!INAPPLICABLE_CANDIDATE!>addListener<!>(ListenerImpl<T, MyFuture<T>>())
     addListener { }
 }
 
diff --git a/compiler/testData/diagnostics/tests/samConversions/samConversionsWithSmartCasts.fir.kt b/compiler/testData/diagnostics/tests/samConversions/samConversionsWithSmartCasts.fir.kt
index a95ff868f00..329a29f52dd 100644
--- a/compiler/testData/diagnostics/tests/samConversions/samConversionsWithSmartCasts.fir.kt
+++ b/compiler/testData/diagnostics/tests/samConversions/samConversionsWithSmartCasts.fir.kt
@@ -49,11 +49,11 @@ fun test6(a: Any) {
 
 fun test7(a: (Int) -> Int) {
     a as () -> Unit
-    J().<!INAPPLICABLE_CANDIDATE!>run1<!>(a)
+    J().run1(a)
 }
 
 fun test8(a: () -> Unit) {
-    J().<!INAPPLICABLE_CANDIDATE!>run1<!>(J.id(a))
+    J().run1(J.id(a))
 }
 
 fun test9() {
diff --git a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.kt.txt b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.kt.txt
index ee1b3d61c77..85ebe18232e 100644
--- a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.kt.txt
+++ b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.kt.txt
@@ -1,24 +1,24 @@
 fun test1(a: Function0<Unit>) {
   when {
-    a is Runnable -> runStatic(r = a /*as Runnable */)
+    a is Runnable -> runStatic(r = a /*as Runnable */ /*-> Runnable? */)
   }
 }
 
 fun test2(a: Function0<Unit>) {
   when {
-    a is Runnable -> J().run1(r = a /*as Runnable */)
+    a is Runnable -> J().run1(r = a /*as Runnable */ /*-> Runnable? */)
   }
 }
 
 fun test3(a: Function0<Unit>) {
   when {
-    a is Runnable -> J().run2(r1 = a /*as Runnable */, r2 = a /*as Runnable */)
+    a is Runnable -> J().run2(r1 = a /*as Runnable */ /*-> Runnable? */, r2 = a /*as Runnable */ /*-> Runnable? */)
   }
 }
 
 fun test4(a: Function0<Unit>, b: Function0<Unit>) {
   when {
-    a is Runnable -> J().run2(r1 = a /*as Runnable */, r2 = b /*-> Runnable? */)
+    a is Runnable -> J().run2(r1 = a /*as Runnable */ /*-> Runnable? */, r2 = b /*-> Runnable? */)
   }
 }
 
@@ -32,7 +32,7 @@ fun test5x(a: Any) {
   when {
     a is Runnable -> { // BLOCK
       a /*as Runnable */ as Function0<Unit> /*~> Unit */
-      J().run1(r = a /*as Runnable */)
+      J().run1(r = a /*as Runnable */ /*-> Runnable? */)
     }
   }
 }
@@ -44,11 +44,11 @@ fun test6(a: Any) {
 
 fun test7(a: Function1<Int, Int>) {
   a as Function0<Unit> /*~> Unit */
-  error("") /* ErrorCallExpression */a /*as Function0<Unit> */;
+  J().run1(r = a /*as Function0<Unit> */ /*-> Runnable? */)
 }
 
 fun test8(a: Function0<Unit>) {
-  error("") /* ErrorCallExpression */id<Function0<Unit>?>(x = a);
+  J().run1(r = id<Function0<Unit>?>(x = a) /*-> Runnable? */)
 }
 
 fun test9() {
diff --git a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
index 40cc1ac952e..5a22093c4e2 100644
--- a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
+++ b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
@@ -7,8 +7,9 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test1' type=kotlin.Function0<kotlin.Unit> origin=null
           then: CALL 'public open fun runStatic (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
-            r: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-              GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test1' type=kotlin.Function0<kotlin.Unit> origin=null
+            r: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+              TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test1' type=kotlin.Function0<kotlin.Unit> origin=null
   FUN name:test2 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
@@ -18,8 +19,9 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test2' type=kotlin.Function0<kotlin.Unit> origin=null
           then: CALL 'public open fun run1 (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
             $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
-            r: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-              GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test2' type=kotlin.Function0<kotlin.Unit> origin=null
+            r: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+              TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test2' type=kotlin.Function0<kotlin.Unit> origin=null
   FUN name:test3 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
@@ -29,10 +31,12 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
           then: CALL 'public open fun run2 (r1: java.lang.Runnable?, r2: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
             $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
-            r1: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-              GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
-            r2: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-              GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
+            r1: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+              TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
+            r2: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+              TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
   FUN name:test4 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>, b:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     VALUE_PARAMETER name:b index:1 type:kotlin.Function0<kotlin.Unit>
@@ -43,8 +47,9 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test4' type=kotlin.Function0<kotlin.Unit> origin=null
           then: CALL 'public open fun run2 (r1: java.lang.Runnable?, r2: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
             $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
-            r1: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-              GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test4' type=kotlin.Function0<kotlin.Unit> origin=null
+            r1: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+              TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test4' type=kotlin.Function0<kotlin.Unit> origin=null
             r2: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
               GET_VAR 'b: kotlin.Function0<kotlin.Unit> declared in <root>.test4' type=kotlin.Function0<kotlin.Unit> origin=null
   FUN name:test5 visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
@@ -72,8 +77,9 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
                   GET_VAR 'a: kotlin.Any declared in <root>.test5x' type=kotlin.Any origin=null
             CALL 'public open fun run1 (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
               $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
-              r: TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
-                GET_VAR 'a: kotlin.Any declared in <root>.test5x' type=kotlin.Any origin=null
+              r: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+                TYPE_OP type=java.lang.Runnable origin=IMPLICIT_CAST typeOperand=java.lang.Runnable
+                  GET_VAR 'a: kotlin.Any declared in <root>.test5x' type=kotlin.Any origin=null
   FUN name:test6 visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
@@ -91,16 +97,20 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
       TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
         TYPE_OP type=kotlin.Function0<kotlin.Unit> origin=CAST typeOperand=kotlin.Function0<kotlin.Unit>
           GET_VAR 'a: kotlin.Function1<kotlin.Int, kotlin.Int> declared in <root>.test7' type=kotlin.Function1<kotlin.Int, kotlin.Int> origin=null
-      ERROR_CALL 'Unresolved reference: <Inapplicable(INAPPLICABLE): /J.run1>#' type=kotlin.Unit
-        TYPE_OP type=kotlin.Function0<kotlin.Unit> origin=IMPLICIT_CAST typeOperand=kotlin.Function0<kotlin.Unit>
-          GET_VAR 'a: kotlin.Function1<kotlin.Int, kotlin.Int> declared in <root>.test7' type=kotlin.Function1<kotlin.Int, kotlin.Int> origin=null
+      CALL 'public open fun run1 (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
+        $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
+        r: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+          TYPE_OP type=kotlin.Function0<kotlin.Unit> origin=IMPLICIT_CAST typeOperand=kotlin.Function0<kotlin.Unit>
+            GET_VAR 'a: kotlin.Function1<kotlin.Int, kotlin.Int> declared in <root>.test7' type=kotlin.Function1<kotlin.Int, kotlin.Int> origin=null
   FUN name:test8 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
-      ERROR_CALL 'Unresolved reference: <Inapplicable(INAPPLICABLE): /J.run1>#' type=kotlin.Unit
-        CALL 'public open fun id <T> (x: T of <root>.J.id?): T of <root>.J.id? declared in <root>.J' type=kotlin.Function0<kotlin.Unit>? origin=null
-          <T>: kotlin.Function0<kotlin.Unit>?
-          x: GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test8' type=kotlin.Function0<kotlin.Unit> origin=null
+      CALL 'public open fun run1 (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
+        $this: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.J' type=<root>.J origin=null
+        r: TYPE_OP type=java.lang.Runnable? origin=SAM_CONVERSION typeOperand=java.lang.Runnable?
+          CALL 'public open fun id <T> (x: T of <root>.J.id?): T of <root>.J.id? declared in <root>.J' type=kotlin.Function0<kotlin.Unit>? origin=null
+            <T>: kotlin.Function0<kotlin.Unit>?
+            x: GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test8' type=kotlin.Function0<kotlin.Unit> origin=null
   FUN name:test9 visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY
       CALL 'public open fun run1 (r: java.lang.Runnable?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null