diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index a9c863f1bd7..274f6e20138 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -29277,6 +29277,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperType.kt");
             }
 
+            @Test
+            @TestMetadata("extFunctionTypeAsSuperTypeRestrictionLifted.kt")
+            public void testExtFunctionTypeAsSuperTypeRestrictionLifted() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt");
+            }
+
             @Test
             @TestMetadata("findClosestCorrespondingSupertype.kt")
             public void testFindClosestCorrespondingSupertype() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
index 769ba6edc9b..870dd19eaeb 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
@@ -29277,6 +29277,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperType.kt");
             }
 
+            @Test
+            @TestMetadata("extFunctionTypeAsSuperTypeRestrictionLifted.kt")
+            public void testExtFunctionTypeAsSuperTypeRestrictionLifted() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt");
+            }
+
             @Test
             @TestMetadata("findClosestCorrespondingSupertype.kt")
             public void testFindClosestCorrespondingSupertype() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
index e56aa15bf0b..35ef3768aa4 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
@@ -29277,6 +29277,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperType.kt");
             }
 
+            @Test
+            @TestMetadata("extFunctionTypeAsSuperTypeRestrictionLifted.kt")
+            public void testExtFunctionTypeAsSuperTypeRestrictionLifted() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt");
+            }
+
             @Test
             @TestMetadata("findClosestCorrespondingSupertype.kt")
             public void testFindClosestCorrespondingSupertype() throws Exception {
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
index 2f5eeccc3b7..92fc7466a1b 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -17,6 +18,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.withSuppressedDiagnostics
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.modality
 import org.jetbrains.kotlin.fir.declarations.utils.visibility
+import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
@@ -42,7 +44,9 @@ object FirSupertypesChecker : FirClassChecker() {
                     reporter.reportOn(superTypeRef.source, FirErrors.NULLABLE_SUPERTYPE, context)
                     nullableSupertypeReported = true
                 }
-                if (!extensionFunctionSupertypeReported && coneType.isExtensionFunctionType) {
+                if (!extensionFunctionSupertypeReported && coneType.isExtensionFunctionType &&
+                    !context.session.languageVersionSettings.supportsFeature(LanguageFeature.FunctionalTypeWithExtensionAsSupertype)
+                ) {
                     reporter.reportOn(superTypeRef.source, FirErrors.SUPERTYPE_IS_EXTENSION_FUNCTION_TYPE, context)
                     extensionFunctionSupertypeReported = true
                 }
diff --git a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
index 532d612fae8..3c56ac37c8b 100644
--- a/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
@@ -15754,6 +15754,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @Test
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @Test
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
index 42ed4515c97..22cb52c9847 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
@@ -583,7 +583,9 @@ public class BodyResolver {
             if (classDescriptor != null) {
                 if (ErrorUtils.isError(classDescriptor)) continue;
 
-                if (FunctionTypesKt.isExtensionFunctionType(supertype)) {
+                if (FunctionTypesKt.isExtensionFunctionType(supertype) &&
+                    !languageVersionSettings.supportsFeature(LanguageFeature.FunctionalTypeWithExtensionAsSupertype)
+                ) {
                     trace.report(SUPERTYPE_IS_EXTENSION_FUNCTION_TYPE.on(typeReference));
                 }
                 else if (FunctionTypesKt.isSuspendFunctionType(supertype) &&
diff --git a/compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt b/compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt
new file mode 100644
index 00000000000..72e5f377313
--- /dev/null
+++ b/compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt
@@ -0,0 +1,15 @@
+// !LANGUAGE: +FunctionalTypeWithExtensionAsSupertype
+// IGNORE_BACKEND: JS, JS_IR, WASM
+
+interface I: (String) -> String
+
+class C: String.() -> String, I {
+    override fun invoke(p1: String): String = p1
+}
+
+fun box(): String {
+    val c = C()
+    if (c("OK") != "OK") return c("OK")
+    val ext: String.() -> String = c
+    return "OK".ext()
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt b/compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt
new file mode 100644
index 00000000000..05d324f32be
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt
@@ -0,0 +1,27 @@
+// FIR_IDENTICAL
+// !LANGUAGE: +FunctionalTypeWithExtensionAsSupertype
+// SKIP_TXT
+class A : Double.() -> Unit {
+    override fun invoke(p1: Double) {}
+}
+
+class B : Int.(Double) -> Unit {
+    override fun invoke(p1: Int, p2: Double) {}
+}
+
+open class C {}
+
+abstract class A0 : C.() -> Int
+abstract class A1 : C.(Int) -> Int
+abstract class A2 : C.(Int, String) -> Int
+
+open class D<T> {}
+
+abstract class B0<T> : D<T>.() -> Int
+abstract class B1<T> : D<T>.(C) -> Int
+abstract class B2<T> : D<T>.(T, C) -> T
+
+interface E<T> {}
+
+abstract class C0: C(), Int.() -> Double
+abstract class C1<T>: C(), E<T>, Int.(C) -> Double
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index ba60e33b315..08364b4a459 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -29373,6 +29373,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperType.kt");
             }
 
+            @Test
+            @TestMetadata("extFunctionTypeAsSuperTypeRestrictionLifted.kt")
+            public void testExtFunctionTypeAsSuperTypeRestrictionLifted() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/extFunctionTypeAsSuperTypeRestrictionLifted.kt");
+            }
+
             @Test
             @TestMetadata("findClosestCorrespondingSupertype.kt")
             public void testFindClosestCorrespondingSupertype() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
index a1530c7410d..2d643e27707 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
@@ -15676,6 +15676,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @Test
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @Test
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
index be1326a208f..4a5a907139e 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
@@ -15754,6 +15754,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @Test
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @Test
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index 9f5dd59475b..475076c5fba 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -12889,6 +12889,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
             runTest("compiler/testData/codegen/box/extensionFunctions/kt1061.kt");
diff --git a/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt b/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
index 2d955cae41b..dbfad9b1cbb 100644
--- a/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
+++ b/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
@@ -253,6 +253,7 @@ enum class LanguageFeature(
     InlineClasses(KOTLIN_1_3, defaultState = State.ENABLED_WITH_WARNING, kind = UNSTABLE_FEATURE),
     ProhibitComparisonOfIncompatibleClasses(sinceVersion = null, kind = BUG_FIX, defaultState = State.DISABLED),
     ExplicitBackingFields(sinceVersion = null, defaultState = State.DISABLED, kind = UNSTABLE_FEATURE),
+    FunctionalTypeWithExtensionAsSupertype(sinceVersion = KOTLIN_1_6, defaultState = State.DISABLED),
 
     ;
 
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
index cb98a76f910..74e0380c7eb 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
@@ -11408,6 +11408,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
             runTest("compiler/testData/codegen/box/extensionFunctions/kt1061.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
index 46432a78971..8aaa191c19f 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
@@ -10814,6 +10814,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
             runTest("compiler/testData/codegen/box/extensionFunctions/kt1061.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index 743b72c308b..4d4561fc2b4 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -10779,6 +10779,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
             runTest("compiler/testData/codegen/box/extensionFunctions/kt1061.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
index f0f3179f63d..42b4ed08fee 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
@@ -10075,6 +10075,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/extensionFunctions/executionOrder.kt");
         }
 
+        @TestMetadata("extensionFunctionAsSupertype.kt")
+        public void testExtensionFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/codegen/box/extensionFunctions/extensionFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt1061.kt")
         public void testKt1061() throws Exception {
             runTest("compiler/testData/codegen/box/extensionFunctions/kt1061.kt");