diff --git a/analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt b/analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt
index 0560c97346d..06dc82943fb 100644
--- a/analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt
+++ b/analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt
@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.analysis.api.symbols.*
 import org.jetbrains.kotlin.analysis.api.types.KtType
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.name.ClassId
@@ -341,7 +342,8 @@ private object FirToKtConversionCreator {
         FirModuleData::class,
         ExpectActualCompatibility.Incompatible::class,
         DeprecationInfo::class,
-        CallableId::class
+        CallableId::class,
+        ClassKind::class,
     )
 
     private val KType.kClass: KClass<*>
diff --git a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt
index 7f1398d965a..cc50a6cbfaf 100644
--- a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt
+++ b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt
@@ -5,13 +5,64 @@
 
 package org.jetbrains.kotlin.analysis.api.fir.diagnostics
 
+import com.intellij.psi.PsiElement
+import com.intellij.psi.impl.source.tree.LeafPsiElement
 import org.jetbrains.kotlin.fir.FirPsiSourceElement
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirPsiDiagnostic
 import org.jetbrains.kotlin.fir.analysis.diagnostics.jvm.FirJvmErrors
+import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirClass
+import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirProperty
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.declarations.FirTypeParameter
+import org.jetbrains.kotlin.fir.declarations.FirVariable
 import org.jetbrains.kotlin.fir.psi
+import org.jetbrains.kotlin.psi.KtAnnotationEntry
+import org.jetbrains.kotlin.psi.KtAnonymousInitializer
+import org.jetbrains.kotlin.psi.KtArrayAccessExpression
+import org.jetbrains.kotlin.psi.KtBackingField
+import org.jetbrains.kotlin.psi.KtBinaryExpression
+import org.jetbrains.kotlin.psi.KtBinaryExpressionWithTypeRHS
+import org.jetbrains.kotlin.psi.KtCallExpression
+import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtConstructor
+import org.jetbrains.kotlin.psi.KtConstructorDelegationCall
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtDeclarationWithBody
+import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
+import org.jetbrains.kotlin.psi.KtDestructuringDeclaration
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtEnumEntry
 import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtExpressionWithLabel
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtIfExpression
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.KtModifierListOwner
+import org.jetbrains.kotlin.psi.KtNameReferenceExpression
+import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.KtObjectDeclaration
+import org.jetbrains.kotlin.psi.KtParameter
+import org.jetbrains.kotlin.psi.KtPrimaryConstructor
+import org.jetbrains.kotlin.psi.KtProperty
+import org.jetbrains.kotlin.psi.KtPropertyAccessor
+import org.jetbrains.kotlin.psi.KtReturnExpression
+import org.jetbrains.kotlin.psi.KtSimpleNameExpression
+import org.jetbrains.kotlin.psi.KtSuperExpression
+import org.jetbrains.kotlin.psi.KtTypeAlias
+import org.jetbrains.kotlin.psi.KtTypeParameter
+import org.jetbrains.kotlin.psi.KtTypeProjection
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.psi.KtValueArgument
+import org.jetbrains.kotlin.psi.KtVariableDeclaration
+import org.jetbrains.kotlin.psi.KtWhenCondition
+import org.jetbrains.kotlin.psi.KtWhenEntry
+import org.jetbrains.kotlin.psi.KtWhenExpression
 
 /*
  * This file was generated automatically
@@ -446,6 +497,8 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
     }
     add(FirErrors.SEALED_SUPERTYPE_IN_LOCAL_CLASS) { firDiagnostic ->
         SealedSupertypeInLocalClassImpl(
+            firDiagnostic.a,
+            firDiagnostic.b,
             firDiagnostic as FirPsiDiagnostic,
             token,
         )
diff --git a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt
index 4f2ce931e8b..ac2c736cc8a 100644
--- a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt
+++ b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt
@@ -8,11 +8,18 @@ package org.jetbrains.kotlin.analysis.api.fir.diagnostics
 import com.intellij.psi.PsiElement
 import com.intellij.psi.impl.source.tree.LeafPsiElement
 import org.jetbrains.kotlin.analysis.api.diagnostics.KtDiagnosticWithPsi
-import org.jetbrains.kotlin.analysis.api.symbols.*
+import org.jetbrains.kotlin.analysis.api.symbols.KtCallableSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtClassLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtFunctionLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtTypeParameterSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtVariableLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtVariableSymbol
 import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.contracts.description.EventOccurrencesRange
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.EffectiveVisibility
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.diagnostics.WhenMissingCase
@@ -24,7 +31,49 @@ import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtAnnotationEntry
+import org.jetbrains.kotlin.psi.KtAnonymousInitializer
+import org.jetbrains.kotlin.psi.KtArrayAccessExpression
+import org.jetbrains.kotlin.psi.KtBackingField
+import org.jetbrains.kotlin.psi.KtBinaryExpression
+import org.jetbrains.kotlin.psi.KtBinaryExpressionWithTypeRHS
+import org.jetbrains.kotlin.psi.KtCallExpression
+import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtConstructor
+import org.jetbrains.kotlin.psi.KtConstructorDelegationCall
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtDeclarationWithBody
+import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
+import org.jetbrains.kotlin.psi.KtDestructuringDeclaration
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtEnumEntry
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtExpressionWithLabel
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtIfExpression
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.KtModifierListOwner
+import org.jetbrains.kotlin.psi.KtNameReferenceExpression
+import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.KtObjectDeclaration
+import org.jetbrains.kotlin.psi.KtParameter
+import org.jetbrains.kotlin.psi.KtPrimaryConstructor
+import org.jetbrains.kotlin.psi.KtProperty
+import org.jetbrains.kotlin.psi.KtPropertyAccessor
+import org.jetbrains.kotlin.psi.KtReturnExpression
+import org.jetbrains.kotlin.psi.KtSimpleNameExpression
+import org.jetbrains.kotlin.psi.KtSuperExpression
+import org.jetbrains.kotlin.psi.KtTypeAlias
+import org.jetbrains.kotlin.psi.KtTypeParameter
+import org.jetbrains.kotlin.psi.KtTypeProjection
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.psi.KtValueArgument
+import org.jetbrains.kotlin.psi.KtVariableDeclaration
+import org.jetbrains.kotlin.psi.KtWhenCondition
+import org.jetbrains.kotlin.psi.KtWhenEntry
+import org.jetbrains.kotlin.psi.KtWhenExpression
 import org.jetbrains.kotlin.resolve.ForbiddenNamedArgumentsTarget
 import org.jetbrains.kotlin.resolve.deprecation.DeprecationInfo
 import org.jetbrains.kotlin.resolve.multiplatform.ExpectActualCompatibility.Incompatible
@@ -329,6 +378,8 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
 
     abstract class SealedSupertypeInLocalClass : KtFirDiagnostic<KtTypeReference>() {
         override val diagnosticClass get() = SealedSupertypeInLocalClass::class
+        abstract val declarationType: String
+        abstract val sealedClassKind: ClassKind
     }
 
     abstract class SealedInheritorInDifferentPackage : KtFirDiagnostic<KtTypeReference>() {
diff --git a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
index 9bced8b2761..e7771cad897 100644
--- a/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
+++ b/analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
@@ -7,12 +7,19 @@ package org.jetbrains.kotlin.analysis.api.fir.diagnostics
 
 import com.intellij.psi.PsiElement
 import com.intellij.psi.impl.source.tree.LeafPsiElement
-import org.jetbrains.kotlin.analysis.api.symbols.*
+import org.jetbrains.kotlin.analysis.api.symbols.KtCallableSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtClassLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtFunctionLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtTypeParameterSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtVariableLikeSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtVariableSymbol
 import org.jetbrains.kotlin.analysis.api.tokens.ValidityToken
 import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.contracts.description.EventOccurrencesRange
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.EffectiveVisibility
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.diagnostics.WhenMissingCase
@@ -25,7 +32,49 @@ import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.KtAnnotationEntry
+import org.jetbrains.kotlin.psi.KtAnonymousInitializer
+import org.jetbrains.kotlin.psi.KtArrayAccessExpression
+import org.jetbrains.kotlin.psi.KtBackingField
+import org.jetbrains.kotlin.psi.KtBinaryExpression
+import org.jetbrains.kotlin.psi.KtBinaryExpressionWithTypeRHS
+import org.jetbrains.kotlin.psi.KtCallExpression
+import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtConstructor
+import org.jetbrains.kotlin.psi.KtConstructorDelegationCall
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtDeclarationWithBody
+import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
+import org.jetbrains.kotlin.psi.KtDestructuringDeclaration
+import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtEnumEntry
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtExpressionWithLabel
+import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtIfExpression
+import org.jetbrains.kotlin.psi.KtImportDirective
+import org.jetbrains.kotlin.psi.KtModifierListOwner
+import org.jetbrains.kotlin.psi.KtNameReferenceExpression
+import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.KtObjectDeclaration
+import org.jetbrains.kotlin.psi.KtParameter
+import org.jetbrains.kotlin.psi.KtPrimaryConstructor
+import org.jetbrains.kotlin.psi.KtProperty
+import org.jetbrains.kotlin.psi.KtPropertyAccessor
+import org.jetbrains.kotlin.psi.KtReturnExpression
+import org.jetbrains.kotlin.psi.KtSimpleNameExpression
+import org.jetbrains.kotlin.psi.KtSuperExpression
+import org.jetbrains.kotlin.psi.KtTypeAlias
+import org.jetbrains.kotlin.psi.KtTypeParameter
+import org.jetbrains.kotlin.psi.KtTypeProjection
+import org.jetbrains.kotlin.psi.KtTypeReference
+import org.jetbrains.kotlin.psi.KtValueArgument
+import org.jetbrains.kotlin.psi.KtVariableDeclaration
+import org.jetbrains.kotlin.psi.KtWhenCondition
+import org.jetbrains.kotlin.psi.KtWhenEntry
+import org.jetbrains.kotlin.psi.KtWhenExpression
 import org.jetbrains.kotlin.resolve.ForbiddenNamedArgumentsTarget
 import org.jetbrains.kotlin.resolve.deprecation.DeprecationInfo
 import org.jetbrains.kotlin.resolve.multiplatform.ExpectActualCompatibility.Incompatible
@@ -394,6 +443,8 @@ internal class SealedSupertypeImpl(
 ) : KtFirDiagnostic.SealedSupertype(), KtAbstractFirDiagnostic<KtTypeReference>
 
 internal class SealedSupertypeInLocalClassImpl(
+    override val declarationType: String,
+    override val sealedClassKind: ClassKind,
     override val firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,
 ) : KtFirDiagnostic.SealedSupertypeInLocalClass(), KtAbstractFirDiagnostic<KtTypeReference>
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 d4e2323c726..0a549f6f1a2 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
@@ -26271,6 +26271,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/sealed/RedundantAbstract.kt");
             }
 
+            @Test
+            @TestMetadata("sealedInheritorErrorMessage.kt")
+            public void testSealedInheritorErrorMessage() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt");
+            }
+
             @Test
             @TestMetadata("TreeWhen.kt")
             public void testTreeWhen() 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 64829c82a08..1cb774e47c3 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
@@ -26271,6 +26271,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/sealed/RedundantAbstract.kt");
             }
 
+            @Test
+            @TestMetadata("sealedInheritorErrorMessage.kt")
+            public void testSealedInheritorErrorMessage() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt");
+            }
+
             @Test
             @TestMetadata("TreeWhen.kt")
             public void testTreeWhen() 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 0978fac834b..9963a0bc5c2 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
@@ -26271,6 +26271,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/sealed/RedundantAbstract.kt");
             }
 
+            @Test
+            @TestMetadata("sealedInheritorErrorMessage.kt")
+            public void testSealedInheritorErrorMessage() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt");
+            }
+
             @Test
             @TestMetadata("TreeWhen.kt")
             public void testTreeWhen() throws Exception {
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
index a2424125ad3..1715861b594 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
@@ -10,6 +10,7 @@ import com.intellij.psi.impl.source.tree.LeafPsiElement
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.contracts.description.EventOccurrencesRange
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.EffectiveVisibility
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.diagnostics.WhenMissingCase
@@ -170,7 +171,10 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val SUPERTYPE_APPEARS_TWICE by error<KtTypeReference>()
         val CLASS_IN_SUPERTYPE_FOR_ENUM by error<KtTypeReference>()
         val SEALED_SUPERTYPE by error<KtTypeReference>()
-        val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error<KtTypeReference>()
+        val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error<KtTypeReference> {
+            parameter<String>("declarationType")
+            parameter<ClassKind>("sealedClassKind")
+        }
         val SEALED_INHERITOR_IN_DIFFERENT_PACKAGE by error<KtTypeReference>()
         val SEALED_INHERITOR_IN_DIFFERENT_MODULE by error<KtTypeReference>()
         val CLASS_INHERITS_JAVA_SEALED_CLASS by error<KtTypeReference>()
diff --git a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
index dfab16418bc..56721271140 100644
--- a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
+++ b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.config.LanguageFeature.RestrictRetentionForExpressio
 import org.jetbrains.kotlin.config.LanguageFeature.RestrictionOfValReassignmentViaBackingField
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.contracts.description.EventOccurrencesRange
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.EffectiveVisibility
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.diagnostics.WhenMissingCase
@@ -174,7 +175,7 @@ object FirErrors {
     val SUPERTYPE_APPEARS_TWICE by error0<KtTypeReference>()
     val CLASS_IN_SUPERTYPE_FOR_ENUM by error0<KtTypeReference>()
     val SEALED_SUPERTYPE by error0<KtTypeReference>()
-    val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error0<KtTypeReference>()
+    val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error2<KtTypeReference, String, ClassKind>()
     val SEALED_INHERITOR_IN_DIFFERENT_PACKAGE by error0<KtTypeReference>()
     val SEALED_INHERITOR_IN_DIFFERENT_MODULE by error0<KtTypeReference>()
     val CLASS_INHERITS_JAVA_SEALED_CLASS by error0<KtTypeReference>()
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSealedSupertypeChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSealedSupertypeChecker.kt
index 8abe4b6c7d8..3d5cc9dac50 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSealedSupertypeChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSealedSupertypeChecker.kt
@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.declarations.FirAnonymousObject
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
 import org.jetbrains.kotlin.fir.declarations.utils.classId
@@ -65,10 +66,17 @@ object FirSealedSupertypeChecker : FirClassChecker() {
                 continue
             }
 
-            val classSymbol = context.session.symbolProvider.getClassLikeSymbolByClassId(classId) as? FirRegularClassSymbol ?: continue
+            val superClassSymbol = context.session.symbolProvider.getClassLikeSymbolByClassId(classId) as? FirRegularClassSymbol ?: continue
 
-            if (classSymbol.modality == Modality.SEALED) {
-                reporter.reportOn(it.source, FirErrors.SEALED_SUPERTYPE_IN_LOCAL_CLASS, context)
+            if (superClassSymbol.modality == Modality.SEALED) {
+                val declarationType = if (declaration is FirAnonymousObject) "Anonymous object" else "Local class"
+                reporter.reportOn(
+                    it.source,
+                    FirErrors.SEALED_SUPERTYPE_IN_LOCAL_CLASS,
+                    declarationType,
+                    superClassSymbol.classKind,
+                    context
+                )
                 return
             }
         }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
index d570435f790..881c513b263 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.analysis.diagnostics
 
+import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.CLASS_KIND
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.RENDER_POSITION_VARIANCE
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.STRING
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.commaSeparated
@@ -614,7 +615,7 @@ class FirDefaultErrorMessages {
             map.put(SUPERTYPE_APPEARS_TWICE, "A supertype appears twice")
             map.put(CLASS_IN_SUPERTYPE_FOR_ENUM, "Enum class cannot inherit from classes")
             map.put(SEALED_SUPERTYPE, "This type is sealed, so it can be inherited by only its own nested classes or objects")
-            map.put(SEALED_SUPERTYPE_IN_LOCAL_CLASS, "Local class cannot extend a sealed class")
+            map.put(SEALED_SUPERTYPE_IN_LOCAL_CLASS, "{0} cannot extend a sealed {1}", STRING, CLASS_KIND)
             map.put(SEALED_INHERITOR_IN_DIFFERENT_PACKAGE, "A class can only inherit from a sealed class or interface declared in the same package")
             map.put(SEALED_INHERITOR_IN_DIFFERENT_MODULE, "Inheritance of sealed classes or interfaces from different module is prohibited")
             map.put(CLASS_INHERITS_JAVA_SEALED_CLASS, "Inheritance of Java sealed classes is prohibited")
diff --git a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/rendering/CommonRenderers.kt b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/rendering/CommonRenderers.kt
index 7332e95c8a6..81c7104645f 100644
--- a/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/rendering/CommonRenderers.kt
+++ b/compiler/frontend.common-psi/src/org/jetbrains/kotlin/diagnostics/rendering/CommonRenderers.kt
@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.diagnostics.rendering
 
 import com.intellij.openapi.util.text.StringUtil
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.types.Variance
 import java.io.PrintWriter
 import java.io.StringWriter
@@ -33,6 +34,18 @@ object CommonRenderers {
         }
     }
 
+    @JvmField
+    val CLASS_KIND = Renderer { classKind: ClassKind ->
+        when (classKind) {
+            ClassKind.CLASS -> "class"
+            ClassKind.INTERFACE -> "interface"
+            ClassKind.ENUM_CLASS -> "enum class"
+            ClassKind.ENUM_ENTRY -> "enum entry"
+            ClassKind.ANNOTATION_CLASS -> "annotation class"
+            ClassKind.OBJECT -> "object"
+        }
+    }
+
     @JvmStatic
     fun <T> commaSeparated(itemRenderer: DiagnosticParameterRenderer<T>) = ContextDependentRenderer<Collection<T>> { collection, context ->
         buildString {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
index 0a93c1144fd..db534890bb3 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
@@ -445,7 +445,7 @@ public interface Errors {
     // Sealed-specific
     DiagnosticFactory0<KtCallExpression> SEALED_CLASS_CONSTRUCTOR_CALL = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> SEALED_SUPERTYPE = DiagnosticFactory0.create(ERROR);
-    DiagnosticFactory0<KtTypeReference> SEALED_SUPERTYPE_IN_LOCAL_CLASS = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory2<KtTypeReference, String, ClassKind> SEALED_SUPERTYPE_IN_LOCAL_CLASS = DiagnosticFactory2.create(ERROR);
     DiagnosticFactory2<KtTypeReference, FqName, FqName> SEALED_INHERITOR_IN_DIFFERENT_PACKAGE = DiagnosticFactory2.create(ERROR);
     DiagnosticFactory0<KtTypeReference> SEALED_INHERITOR_IN_DIFFERENT_MODULE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> CLASS_INHERITS_JAVA_SEALED_CLASS = DiagnosticFactory0.create(ERROR);
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
index 305ec4009bc..725ecd2430f 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
@@ -658,7 +658,7 @@ public class DefaultErrorMessages {
         MAP.put(FINAL_SUPERTYPE, "This type is final, so it cannot be inherited from");
         MAP.put(DATA_CLASS_CANNOT_HAVE_CLASS_SUPERTYPES, "Data class inheritance from other classes is forbidden");
         MAP.put(SEALED_SUPERTYPE, "This type is sealed, so it can be inherited by only its own nested classes or objects");
-        MAP.put(SEALED_SUPERTYPE_IN_LOCAL_CLASS, "Local class cannot extend a sealed class");
+        MAP.put(SEALED_SUPERTYPE_IN_LOCAL_CLASS, "{0} cannot extend a sealed {1}", STRING, CLASS_KIND);
         MAP.put(SEALED_INHERITOR_IN_DIFFERENT_PACKAGE, "Inheritor of sealed class or interface declared in package {0} but it must be in package {1} where base class is declared", TO_STRING, TO_STRING);
         MAP.put(SEALED_INHERITOR_IN_DIFFERENT_MODULE, "Inheritance of sealed classes or interfaces from different module is prohibited");
         MAP.put(CLASS_INHERITS_JAVA_SEALED_CLASS, "Inheritance of java sealed classes is prohibited");
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
index b647f0fba41..966083f477d 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
@@ -33,6 +33,7 @@ import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
 import org.jetbrains.kotlin.diagnostics.Errors;
 import org.jetbrains.kotlin.lexer.KtTokens;
+import org.jetbrains.kotlin.name.SpecialNames;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.psi.psiUtil.PsiUtilsKt;
 import org.jetbrains.kotlin.resolve.calls.CallResolver;
@@ -669,7 +670,13 @@ public class BodyResolver {
                         }
                     }
                     else {
-                        trace.report(SEALED_SUPERTYPE_IN_LOCAL_CLASS.on(typeReference));
+                        String declarationName;
+                        if (supertypeOwner.getName() == SpecialNames.NO_NAME_PROVIDED) {
+                            declarationName = "Anonymous object";
+                        } else {
+                            declarationName = "Local class";
+                        }
+                        trace.report(SEALED_SUPERTYPE_IN_LOCAL_CLASS.on(typeReference, declarationName, classDescriptor.getKind()));
                     }
                 }
                 else if (ModalityUtilsKt.isFinalOrEnum(classDescriptor)) {
diff --git a/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt b/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt
new file mode 100644
index 00000000000..2d1bac010c6
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt
@@ -0,0 +1,16 @@
+// FIR_IDENTICAL
+// ISSUE: KT-46285
+
+sealed class SealedClass {
+    fun test() {
+        val anon = object : <!SEALED_SUPERTYPE_IN_LOCAL_CLASS("Anonymous object; class")!>SealedClass<!>() {}
+        class Local : <!SEALED_SUPERTYPE_IN_LOCAL_CLASS("Local class; class")!>SealedClass<!>()
+    }
+}
+
+sealed interface SealedInterface {
+    fun test() {
+        val anon = object : <!SEALED_SUPERTYPE_IN_LOCAL_CLASS("Anonymous object; interface")!>SealedInterface<!> {}
+        class Local : <!SEALED_SUPERTYPE_IN_LOCAL_CLASS("Local class; interface")!>SealedInterface<!>
+    }
+}
diff --git a/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.txt b/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.txt
new file mode 100644
index 00000000000..00c144e71a3
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.txt
@@ -0,0 +1,17 @@
+package
+
+public sealed class SealedClass {
+    protected constructor SealedClass()
+    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 final fun test(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public sealed interface SealedInterface {
+    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 fun test(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
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 cf011e8c224..3363d832aa7 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
@@ -26361,6 +26361,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/sealed/RedundantAbstract.kt");
             }
 
+            @Test
+            @TestMetadata("sealedInheritorErrorMessage.kt")
+            public void testSealedInheritorErrorMessage() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/sealed/sealedInheritorErrorMessage.kt");
+            }
+
             @Test
             @TestMetadata("TreeWhen.kt")
             public void testTreeWhen() throws Exception {