[JS IR] Control an inheritance of non-external entity from external

Add a special annotation @JsExternalInheritorsOnly for marking
 external interfaces and classes. The marked interface or class
 can’t be a parent for non external interfaces, classes or objects.

^KT-57423 Fixed

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirJsDiagnosticsList.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.fir.PrivateForInline
 import org.jetbrains.kotlin.fir.checkers.generator.diagnostics.model.DiagnosticList
 import org.jetbrains.kotlin.fir.checkers.generator.diagnostics.model.PositioningStrategy
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.psi.*
@@ -94,6 +95,10 @@ object JS_DIAGNOSTICS_LIST : DiagnosticList("FirJsErrors") {
             parameter<ConeKotlinType>("targetType")
         }
         val EXTERNAL_INTERFACE_AS_CLASS_LITERAL by error<KtElement>()
+        val JS_EXTERNAL_INHERITORS_ONLY by error<KtDeclaration>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT) {
+            parameter<FirClassLikeSymbol<*>>("parent")
+            parameter<FirClassLikeSymbol<*>>("kid")
+        }
     }
 
     val EXPORT by object : DiagnosticGroup("Export") {

compiler/fir/checkers/checkers.js/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/js/FirJsErrors.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.diagnostics.SourceElementPositioningStrategies
 import org.jetbrains.kotlin.diagnostics.rendering.RootDiagnosticRendererFactory
 import org.jetbrains.kotlin.fir.analysis.diagnostics.*
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.psi.KtAnonymousInitializer
@@ -78,6 +79,7 @@ object FirJsErrors {
     val CANNOT_CHECK_FOR_EXTERNAL_INTERFACE by error1<KtElement, ConeKotlinType>()
     val UNCHECKED_CAST_TO_EXTERNAL_INTERFACE by warning2<KtElement, ConeKotlinType, ConeKotlinType>()
     val EXTERNAL_INTERFACE_AS_CLASS_LITERAL by error0<KtElement>()
+    val JS_EXTERNAL_INHERITORS_ONLY by error2<KtDeclaration, FirClassLikeSymbol<*>, FirClassLikeSymbol<*>>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
 
     // Export
     val NESTED_JS_EXPORT by error0<KtElement>()

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/diagnostics/js/FirJsErrorsDefaultMessages.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.IMPLEMENTING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.INLINE_CLASS_IN_EXTERNAL_DECLARATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.INLINE_CLASS_IN_EXTERNAL_DECLARATION_WARNING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.ENUM_CLASS_IN_EXTERNAL_DECLARATION_WARNING
+import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.JS_EXTERNAL_INHERITORS_ONLY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.INLINE_EXTERNAL_DECLARATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.JS_MODULE_PROHIBITED_ON_NON_NATIVE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.JS_MODULE_PROHIBITED_ON_VAR
@@ -153,6 +154,12 @@ object FirJsErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
             "Can''t put non-external declarations in file marked with {0} annotation",
             FirDiagnosticRenderers.RENDER_TYPE
         )
+        map.put(
+            JS_EXTERNAL_INHERITORS_ONLY,
+            "External {0} can''t be a parent of non-external {1}",
+            FirDiagnosticRenderers.RENDER_CLASS_OR_OBJECT_NAME,
+            FirDiagnosticRenderers.RENDER_CLASS_OR_OBJECT_NAME
+        )
         map.put(JS_NAME_PROHIBITED_FOR_EXTENSION_PROPERTY, "@JsName is prohibited for extension properties")
         map.put(JS_NAME_IS_NOT_ON_ALL_ACCESSORS, "@JsName should be on all the property accessors")
         map.put(JS_NAME_PROHIBITED_FOR_NAMED_NATIVE, "@JsName is prohibited for external declaration with explicit name")

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/JsDeclarationCheckers.kt

@@ -36,6 +36,7 @@ object JsDeclarationCheckers : DeclarationCheckers() {
             FirJsMultipleInheritanceChecker,
             FirJsDynamicDeclarationChecker,
             FirJsInheritanceClassChecker,
+            FirJsExternalInheritorOnlyChecker
         )
 
     override val simpleFunctionCheckers: Set<FirSimpleFunctionChecker>

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/declaration/FirJsExternalInheritorOnlyChecker.kt

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis.js.checkers.declaration
+
+import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirClassChecker
+import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors
+import org.jetbrains.kotlin.fir.analysis.js.checkers.isEffectivelyExternal
+import org.jetbrains.kotlin.fir.declarations.FirClass
+import org.jetbrains.kotlin.fir.declarations.hasAnnotation
+import org.jetbrains.kotlin.fir.declarations.utils.superConeTypes
+import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
+import org.jetbrains.kotlin.fir.types.ConeClassLikeType
+import org.jetbrains.kotlin.fir.types.coneTypeSafe
+import org.jetbrains.kotlin.fir.types.toRegularClassSymbol
+import org.jetbrains.kotlin.name.JsStandardClassIds.Annotations.JsExternalInheritorsOnly
+import org.jetbrains.kotlin.utils.addToStdlib.popLast
+
+object FirJsExternalInheritorOnlyChecker : FirClassChecker() {
+    private fun FirClass.forEachParents(context: CheckerContext, f: (FirRegularClassSymbol) -> Unit) {
+        val todo = superConeTypes.toMutableList()
+        val done = hashSetOf<FirRegularClassSymbol>()
+
+        while (todo.isNotEmpty()) {
+            val classSymbol = todo.popLast().toRegularClassSymbol(context.session) ?: continue
+            if (done.add(classSymbol)) {
+                f(classSymbol)
+                classSymbol.resolvedSuperTypeRefs.mapNotNullTo(todo) { it.type as? ConeClassLikeType }
+            }
+        }
+    }
+
+    override fun check(declaration: FirClass, context: CheckerContext, reporter: DiagnosticReporter) {
+        if (!declaration.symbol.isEffectivelyExternal(context)) {
+            declaration.forEachParents(context) { parent ->
+                if (parent.hasAnnotation(JsExternalInheritorsOnly, context.session)) {
+                    reporter.reportOn(
+                        declaration.source,
+                        FirJsErrors.JS_EXTERNAL_INHERITORS_ONLY,
+                        parent,
+                        declaration.symbol,
+                        context
+                    )
+                }
+            }
+        }
+    }
+}

compiler/testData/diagnostics/testsWithJsStdLib/jsExternalInheritorsOnly.kt

@@ -0,0 +1,135 @@
+// FIR_IDENTICAL
+
+@OptIn(ExperimentalStdlibApi::class)
+@JsExternalInheritorsOnly
+external interface ExternalInterfaceX {
+    val x: String
+}
+
+@OptIn(ExperimentalStdlibApi::class)
+@JsExternalInheritorsOnly
+external open class ExternalOpenClassX {
+    val x: String
+}
+
+// check interfaces
+
+external interface ExternalInterfaceXY : ExternalInterfaceX {
+    val y: String
+}
+
+interface <!JS_EXTERNAL_INHERITORS_ONLY!>InterfaceXY<!> : ExternalInterfaceX {
+    val y: String
+}
+
+interface <!JS_EXTERNAL_INHERITORS_ONLY!>InterfaceXYZ<!> : ExternalInterfaceXY {
+    val z: String
+}
+
+// check objects
+
+external object ExternalObjectXY : ExternalInterfaceX {
+    override val x: String
+    val y: String
+}
+
+external object ExternalObjectXYZ : ExternalInterfaceXY {
+    override val x: String
+    override val y: String
+    val z: String
+}
+
+external object ExternalObjectXZ : ExternalOpenClassX {
+    val z: String
+}
+
+<!JS_EXTERNAL_INHERITORS_ONLY!>object ObjectXY<!> : ExternalInterfaceX {
+    override val x: String = "X"
+    val y: String = "Y"
+}
+
+<!JS_EXTERNAL_INHERITORS_ONLY!>object ObjectXYZ<!> : ExternalInterfaceXY {
+    override val x: String = "X"
+    override val y: String = "Y"
+    val z: String = "Z"
+}
+
+<!JS_EXTERNAL_INHERITORS_ONLY!>object ObjectXZ<!> : ExternalOpenClassX() {
+    val z: String = "Z"
+}
+
+// check classes
+
+external class ExternalClassXY : ExternalInterfaceX {
+    override val x: String
+    val y: String
+}
+
+external class ExternalClassXYZ : ExternalInterfaceXY {
+    override val x: String
+    override val y: String
+    val z: String
+}
+
+external open class ExternalOpenClassXZ : ExternalOpenClassX {
+    val z: String
+}
+
+class <!JS_EXTERNAL_INHERITORS_ONLY!>ClassXY<!> : ExternalInterfaceX {
+    override val x: String = "X"
+    val y: String = "Y"
+}
+
+class <!JS_EXTERNAL_INHERITORS_ONLY!>ClassXYZ<!> : ExternalInterfaceXY {
+    override val x: String = "X"
+    override val y: String = "Y"
+    val z: String = "Z"
+}
+
+class <!JS_EXTERNAL_INHERITORS_ONLY!>ClassXZ<!> : ExternalOpenClassX() {
+    val z: String = "Z"
+}
+
+class <!JS_EXTERNAL_INHERITORS_ONLY!>ClassXZY<!> : ExternalOpenClassXZ() {
+    val y: String = "Y"
+}
+
+// check nested
+
+external class ExternalClassNameSpace {
+    @OptIn(ExperimentalStdlibApi::class)
+    @JsExternalInheritorsOnly
+    interface NestedInterfaceX {
+        val x: String
+    }
+
+    interface NestedInterfaceXY : NestedInterfaceX {
+        val y: String
+    }
+}
+
+external interface ExternalInterfaceXY2 : ExternalClassNameSpace.NestedInterfaceX {
+    val y: String
+}
+
+external interface ExternalInterfaceXYZ2 : ExternalClassNameSpace.NestedInterfaceXY {
+    val z: String
+}
+
+interface <!JS_EXTERNAL_INHERITORS_ONLY!>InterfaceXY2<!> : ExternalClassNameSpace.NestedInterfaceX {
+    val y: String
+}
+
+interface <!JS_EXTERNAL_INHERITORS_ONLY!>InterfaceXYZ2<!> : ExternalClassNameSpace.NestedInterfaceXY {
+    val z: String
+}
+
+// multiple inheritance
+
+external class ExternalClassXY2 : ExternalInterfaceX, ExternalOpenClassX {
+    val y: String
+}
+
+class <!JS_EXTERNAL_INHERITORS_ONLY, JS_EXTERNAL_INHERITORS_ONLY!>ClassXY2<!> : ExternalInterfaceX, ExternalOpenClassX() {
+    val y: String = "Y"
+}

compiler/testData/diagnostics/testsWithJsStdLib/jsExternalInheritorsOnly.txt

@@ -0,0 +1,238 @@
+package
+
+public final class ClassXY : ExternalInterfaceX {
+    public constructor ClassXY()
+    public open override /*1*/ val x: kotlin.String = "X"
+    public final val y: kotlin.String = "Y"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class ClassXY2 : ExternalInterfaceX, ExternalOpenClassX {
+    public constructor ClassXY2()
+    public final override /*2*/ /*fake_override*/ val x: kotlin.String
+    public final val y: kotlin.String = "Y"
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class ClassXYZ : ExternalInterfaceXY {
+    public constructor ClassXYZ()
+    public open override /*1*/ val x: kotlin.String = "X"
+    public open override /*1*/ val y: kotlin.String = "Y"
+    public final val z: kotlin.String = "Z"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class ClassXZ : ExternalOpenClassX {
+    public constructor ClassXZ()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.String
+    public final val z: kotlin.String = "Z"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class ClassXZY : ExternalOpenClassXZ {
+    public constructor ClassXZY()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.String
+    public final val y: kotlin.String = "Y"
+    public final override /*1*/ /*fake_override*/ val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final external class ExternalClassNameSpace {
+    public constructor ExternalClassNameSpace()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    @kotlin.OptIn(markerClass = {kotlin.ExperimentalStdlibApi::class}) @kotlin.js.JsExternalInheritorsOnly public interface NestedInterfaceX {
+        public abstract val x: kotlin.String
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public interface NestedInterfaceXY : ExternalClassNameSpace.NestedInterfaceX {
+        public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+        public abstract val y: kotlin.String
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final external class ExternalClassXY : ExternalInterfaceX {
+    public constructor ExternalClassXY()
+    public open override /*1*/ val x: kotlin.String
+    public final val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final external class ExternalClassXY2 : ExternalInterfaceX, ExternalOpenClassX {
+    public constructor ExternalClassXY2()
+    public final override /*2*/ /*fake_override*/ val x: kotlin.String
+    public final val y: kotlin.String
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final external class ExternalClassXYZ : ExternalInterfaceXY {
+    public constructor ExternalClassXYZ()
+    public open override /*1*/ val x: kotlin.String
+    public open override /*1*/ val y: kotlin.String
+    public final val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+@kotlin.OptIn(markerClass = {kotlin.ExperimentalStdlibApi::class}) @kotlin.js.JsExternalInheritorsOnly public external interface ExternalInterfaceX {
+    public abstract val x: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external interface ExternalInterfaceXY : ExternalInterfaceX {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external interface ExternalInterfaceXY2 : ExternalClassNameSpace.NestedInterfaceX {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external interface ExternalInterfaceXYZ2 : ExternalClassNameSpace.NestedInterfaceXY {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract override /*1*/ /*fake_override*/ val y: kotlin.String
+    public abstract val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external object ExternalObjectXY : ExternalInterfaceX {
+    private constructor ExternalObjectXY()
+    public open override /*1*/ val x: kotlin.String
+    public final val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external object ExternalObjectXYZ : ExternalInterfaceXY {
+    private constructor ExternalObjectXYZ()
+    public open override /*1*/ val x: kotlin.String
+    public open override /*1*/ val y: kotlin.String
+    public final val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public external object ExternalObjectXZ : ExternalOpenClassX {
+    private constructor ExternalObjectXZ()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.String
+    public final val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+@kotlin.OptIn(markerClass = {kotlin.ExperimentalStdlibApi::class}) @kotlin.js.JsExternalInheritorsOnly public open external class ExternalOpenClassX {
+    public constructor ExternalOpenClassX()
+    public final val x: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open external class ExternalOpenClassXZ : ExternalOpenClassX {
+    public constructor ExternalOpenClassXZ()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.String
+    public final val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface InterfaceXY : ExternalInterfaceX {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface InterfaceXY2 : ExternalClassNameSpace.NestedInterfaceX {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract val y: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface InterfaceXYZ : ExternalInterfaceXY {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract override /*1*/ /*fake_override*/ val y: kotlin.String
+    public abstract val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface InterfaceXYZ2 : ExternalClassNameSpace.NestedInterfaceXY {
+    public abstract override /*1*/ /*fake_override*/ val x: kotlin.String
+    public abstract override /*1*/ /*fake_override*/ val y: kotlin.String
+    public abstract val z: kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public object ObjectXY : ExternalInterfaceX {
+    private constructor ObjectXY()
+    public open override /*1*/ val x: kotlin.String = "X"
+    public final val y: kotlin.String = "Y"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public object ObjectXYZ : ExternalInterfaceXY {
+    private constructor ObjectXYZ()
+    public open override /*1*/ val x: kotlin.String = "X"
+    public open override /*1*/ val y: kotlin.String = "Y"
+    public final val z: kotlin.String = "Z"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public object ObjectXZ : ExternalOpenClassX {
+    private constructor ObjectXZ()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.String
+    public final val z: kotlin.String = "Z"
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticsTestWithJsStdLibGenerated.java

@@ -36,6 +36,12 @@ public class DiagnosticsTestWithJsStdLibGenerated extends AbstractDiagnosticsTes
         runTest("compiler/testData/diagnostics/testsWithJsStdLib/implementingFunction.kt");
     }
 
+    @Test
+    @TestMetadata("jsExternalInheritorsOnly.kt")
+    public void testJsExternalInheritorsOnly() throws Exception {
+        runTest("compiler/testData/diagnostics/testsWithJsStdLib/jsExternalInheritorsOnly.kt");
+    }
+
     @Test
     @TestMetadata("localClassMetadata.kt")
     public void testLocalClassMetadata() throws Exception {