diff --git a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/CommonizationVisitor.kt b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/CommonizationVisitor.kt
index eed94b29caf..9eaf447b126 100644
--- a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/CommonizationVisitor.kt
+++ b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/core/CommonizationVisitor.kt
@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.descriptors.commonizer.core
 import org.jetbrains.kotlin.descriptors.commonizer.cir.CirType
 import org.jetbrains.kotlin.descriptors.commonizer.cir.CirTypeSignature
 import org.jetbrains.kotlin.descriptors.commonizer.mergedtree.*
-import org.jetbrains.kotlin.descriptors.commonizer.utils.CommonizedGroupMap
+import org.jetbrains.kotlin.descriptors.commonizer.utils.CommonizedGroup
 import org.jetbrains.kotlin.descriptors.commonizer.utils.internedClassId
 
 internal class CommonizationVisitor(
@@ -93,10 +93,10 @@ internal class CommonizationVisitor(
             }
 
             // find out common (and commonized) supertypes
-            val supertypesMap = CommonizedGroupMap<CirTypeSignature, CirType>(node.targetDeclarations.size)
+            val supertypesMap: MutableMap<CirTypeSignature, CommonizedGroup<CirType>> = linkedMapOf() // preserve supertype order
             node.targetDeclarations.forEachIndexed { index, clazz ->
                 for (supertype in clazz!!.supertypes) {
-                    supertypesMap[supertype.signature][index] = supertype
+                    supertypesMap.getOrPut(supertype.signature) { CommonizedGroup(node.targetDeclarations.size) }[index] = supertype
                 }
             }