diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
index 14b0660e6d2..4e1065053db 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt
@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.SyntheticPropertySymbol
 import org.jetbrains.kotlin.fir.resolve.providers.FirProvider
 import org.jetbrains.kotlin.fir.symbols.AccessorSymbol
+import org.jetbrains.kotlin.fir.symbols.Fir2IrClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.ir.IrElement
@@ -302,9 +303,10 @@ internal fun IrClass.findMatchingOverriddenSymbolsFromSupertypes(
     visited: MutableSet<IrClass> = mutableSetOf()
 ): List<IrSymbol> {
     for (superType in superTypes) {
-        val superTypeClass = superType.classOrNull
-        if (superTypeClass is IrClassSymbolImpl || superTypeClass is IrClassPublicSymbolImpl) {
-            superTypeClass.owner.findMatchingOverriddenSymbolsFromThisAndSupertypes(irBuiltIns, target, result, visited)
+        when (val superTypeClass = superType.classOrNull) {
+            is IrClassSymbolImpl, is IrClassPublicSymbolImpl, is Fir2IrClassSymbol -> {
+                superTypeClass.owner.findMatchingOverriddenSymbolsFromThisAndSupertypes(irBuiltIns, target, result, visited)
+            }
         }
     }
     return result
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt
index 285e76cc108..17f31e98d4f 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt
@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.resolve.firProvider
 import org.jetbrains.kotlin.fir.resolve.toSymbol
+import org.jetbrains.kotlin.fir.symbols.Fir2IrClassSymbol
 import org.jetbrains.kotlin.fir.symbols.StandardClassIds
 import org.jetbrains.kotlin.fir.symbols.impl.ConeClassLikeLookupTagImpl
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
@@ -159,15 +160,15 @@ class Fir2IrClassifierStorage(
         parent: IrDeclarationParent? = null,
         origin: IrDeclarationOrigin = IrDeclarationOrigin.DEFINED
     ): IrClass {
-        val descriptor = WrappedClassDescriptor()
         val visibility = regularClass.visibility
         val modality = if (regularClass.classKind == ClassKind.ENUM_CLASS) {
             regularClass.enumClassModality()
         } else {
             regularClass.modality ?: Modality.FINAL
         }
+        val signature = signatureComposer.composeSignature(regularClass)
         val irClass = regularClass.convertWithOffsets { startOffset, endOffset ->
-            symbolTable.declareClass(descriptor) { symbol ->
+            symbolTable.declareClass(signature, { Fir2IrClassSymbol(signature) }) { symbol ->
                 IrClassImpl(
                     startOffset,
                     endOffset,
@@ -185,8 +186,8 @@ class Fir2IrClassifierStorage(
                     isExpect = regularClass.isExpect,
                     isFun = regularClass.isFun
                 ).apply {
-                    metadata = FirMetadataSource.Class(regularClass, descriptor)
-                    descriptor.bind(this)
+                    val descriptor = symbol.descriptor
+                    metadata = FirMetadataSource.Class(regularClass, descriptor as WrappedClassDescriptor)
                 }
             }
         }
@@ -207,19 +208,19 @@ class Fir2IrClassifierStorage(
         name: Name = Name.special("<no name provided>"),
         irParent: IrDeclarationParent? = null
     ): IrClass {
-        val descriptor = WrappedClassDescriptor()
         val origin = IrDeclarationOrigin.DEFINED
         val modality = Modality.FINAL
+        val signature = signatureComposer.composeSignature(anonymousObject)
         val result = anonymousObject.convertWithOffsets { startOffset, endOffset ->
-            symbolTable.declareClass(descriptor) { symbol ->
+            symbolTable.declareClass(signature, { Fir2IrClassSymbol(signature) }) { symbol ->
                 IrClassImpl(
                     startOffset, endOffset, origin, symbol, name,
                     // NB: for unknown reason, IR uses 'CLASS' kind for simple anonymous objects
                     anonymousObject.classKind.takeIf { it == ClassKind.ENUM_ENTRY } ?: ClassKind.CLASS,
                     visibility, modality
                 ).apply {
-                    metadata = FirMetadataSource.Class(anonymousObject, descriptor)
-                    descriptor.bind(this)
+                    val descriptor = symbol.descriptor
+                    metadata = FirMetadataSource.Class(anonymousObject, descriptor as WrappedClassDescriptor)
                     setThisReceiver(anonymousObject.typeParameters)
                     if (irParent != null) {
                         this.parent = irParent
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt
index b067675f2c9..dcccc3a22e7 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt
@@ -398,6 +398,18 @@ open class SymbolTable(
         )
     }
 
+    fun declareClass(
+        sig: IdSignature,
+        symbolFactory: () -> IrClassSymbol,
+        classFactory: (IrClassSymbol) -> IrClass
+    ): IrClass {
+        return classSymbolTable.declare(
+            sig,
+            symbolFactory,
+            classFactory
+        )
+    }
+
     fun declareClassIfNotExists(descriptor: ClassDescriptor, classFactory: (IrClassSymbol) -> IrClass): IrClass {
         return classSymbolTable.declareIfNotExists(descriptor, { createClassSymbol(descriptor) }, classFactory)
     }