diff --git a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/approximationKeys.kt b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/approximationKeys.kt
index 53ad4f7a998..69073237d41 100644
--- a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/approximationKeys.kt
+++ b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/mergedtree/approximationKeys.kt
@@ -8,16 +8,19 @@ package org.jetbrains.kotlin.descriptors.commonizer.mergedtree
 import org.jetbrains.kotlin.descriptors.ConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
+import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.descriptors.commonizer.cir.CirTypeSignature
 import org.jetbrains.kotlin.descriptors.commonizer.core.Commonizer
 import org.jetbrains.kotlin.descriptors.commonizer.utils.intern
 import org.jetbrains.kotlin.descriptors.commonizer.utils.signature
+import org.jetbrains.kotlin.descriptors.commonizer.utils.hashCode
+import org.jetbrains.kotlin.descriptors.commonizer.utils.appendHashCode
 import org.jetbrains.kotlin.name.Name
 
 /** Used for approximation of [PropertyDescriptor]s before running concrete [Commonizer]s */
 data class PropertyApproximationKey(
-    val name: Name,
-    val extensionReceiverParameter: CirTypeSignature?
+    private val name: Name,
+    private val extensionReceiverParameterType: CirTypeSignature?
 ) {
     constructor(property: PropertyDescriptor) : this(
         property.name.intern(),
@@ -26,23 +29,49 @@ data class PropertyApproximationKey(
 }
 
 /** Used for approximation of [SimpleFunctionDescriptor]s before running concrete [Commonizer]s */
-data class FunctionApproximationKey(
-    val name: Name,
-    val valueParameters: List<CirTypeSignature>,
-    val extensionReceiverParameter: CirTypeSignature?
+class FunctionApproximationKey(
+    private val name: Name,
+    private val valueParametersTypes: Array<CirTypeSignature>,
+    private val extensionReceiverParameterType: CirTypeSignature?
 ) {
     constructor(function: SimpleFunctionDescriptor) : this(
         function.name.intern(),
-        function.valueParameters.map { it.type.signature },
+        function.valueParameters.toTypeSignatures(),
         function.extensionReceiverParameter?.type?.signature
     )
+
+    override fun equals(other: Any?): Boolean {
+        if (other !is FunctionApproximationKey)
+            return false
+
+        return name == other.name
+                && valueParametersTypes.contentEquals(other.valueParametersTypes)
+                && extensionReceiverParameterType == other.extensionReceiverParameterType
+    }
+
+    override fun hashCode() = hashCode(name)
+        .appendHashCode(valueParametersTypes)
+        .appendHashCode(extensionReceiverParameterType)
 }
 
 /** Used for approximation of [ConstructorDescriptor]s before running concrete [Commonizer]s */
-data class ConstructorApproximationKey(
-    val valueParameters: List<CirTypeSignature>
+class ConstructorApproximationKey(
+    private val valueParametersTypes: Array<CirTypeSignature>
 ) {
     constructor(constructor: ConstructorDescriptor) : this(
-        constructor.valueParameters.map { it.type.signature }
+        constructor.valueParameters.toTypeSignatures()
     )
-}
\ No newline at end of file
+
+    override fun equals(other: Any?): Boolean {
+        if (other !is ConstructorApproximationKey)
+            return false
+
+        return valueParametersTypes.contentEquals(other.valueParametersTypes)
+    }
+
+    override fun hashCode() = hashCode(valueParametersTypes)
+}
+
+@Suppress("NOTHING_TO_INLINE")
+private inline fun List<ValueParameterDescriptor>.toTypeSignatures(): Array<CirTypeSignature> =
+    Array(size) { index -> this[index].type.signature }
diff --git a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/utils/misc.kt b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/utils/misc.kt
index 739a9eba795..bb13a9a2d9a 100644
--- a/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/utils/misc.kt
+++ b/native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/utils/misc.kt
@@ -31,5 +31,11 @@ internal fun Any?.isNull(): Boolean = this == null
 @Suppress("NOTHING_TO_INLINE")
 inline fun hashCode(value: Any?): Int = value.hashCode()
 
+@Suppress("NOTHING_TO_INLINE")
+inline fun hashCode(array: Array<*>?): Int = array?.contentHashCode() ?: 0
+
 @Suppress("NOTHING_TO_INLINE")
 inline fun Int.appendHashCode(value: Any?): Int = 31 * this + hashCode(value)
+
+@Suppress("NOTHING_TO_INLINE")
+inline fun Int.appendHashCode(array: Array<*>?): Int = 31 * this + hashCode(array)