diff --git a/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/inlineClassMapping.kt b/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/inlineClassMapping.kt
new file mode 100644
index 00000000000..382308fda46
--- /dev/null
+++ b/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/inlineClassMapping.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2010-2019 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.load.kotlin
+
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.ClassifierDescriptor
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.resolve.substitutedUnderlyingType
+import org.jetbrains.kotlin.resolve.unsubstitutedUnderlyingType
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.TypeUtils
+import org.jetbrains.kotlin.types.isNullable
+import org.jetbrains.kotlin.types.typeUtil.makeNullable
+import org.jetbrains.kotlin.types.typeUtil.representativeUpperBound
+
+internal fun computeUnderlyingType(inlineClassType: KotlinType): KotlinType? {
+    if (!shouldUseUnderlyingType(inlineClassType)) return null
+
+    val descriptor = inlineClassType.unsubstitutedUnderlyingType()?.constructor?.declarationDescriptor ?: return null
+    return if (descriptor is TypeParameterDescriptor)
+        descriptor.representativeUpperBound
+    else
+        inlineClassType.substitutedUnderlyingType()
+}
+
+internal fun computeExpandedTypeForInlineClass(inlineClassType: KotlinType): KotlinType? =
+    computeExpandedTypeInner(inlineClassType, hashSetOf())
+
+private fun computeExpandedTypeInner(kotlinType: KotlinType, visitedClassifiers: HashSet<ClassifierDescriptor>): KotlinType? {
+    val classifier = kotlinType.constructor.declarationDescriptor
+        ?: throw AssertionError("Type with a declaration expected: $kotlinType")
+    if (!visitedClassifiers.add(classifier)) return null
+
+    return when {
+        classifier is TypeParameterDescriptor ->
+            computeExpandedTypeInner(classifier.representativeUpperBound, visitedClassifiers)
+                ?.let { expandedUpperBound ->
+                    if (expandedUpperBound.isNullable() || !kotlinType.isMarkedNullable)
+                        expandedUpperBound
+                    else
+                        expandedUpperBound.makeNullable()
+                }
+
+        classifier is ClassDescriptor && classifier.isInline -> {
+            // kotlinType is the boxed inline class type
+
+            val underlyingType = kotlinType.substitutedUnderlyingType() ?: return null
+            val expandedUnderlyingType = computeExpandedTypeInner(underlyingType, visitedClassifiers) ?: return null
+            when {
+                !kotlinType.isNullable() -> expandedUnderlyingType
+
+                // Here inline class type is nullable. Apply nullability to the expandedUnderlyingType.
+
+                // Nullable types become inline class boxes
+                expandedUnderlyingType.isNullable() -> kotlinType
+
+                // Primitives become inline class boxes
+                KotlinBuiltIns.isPrimitiveType(expandedUnderlyingType) -> kotlinType
+
+                // Non-null reference types become nullable reference types
+                else -> expandedUnderlyingType.makeNullable()
+            }
+        }
+
+        else -> kotlinType
+    }
+}
+
+internal fun shouldUseUnderlyingType(inlineClassType: KotlinType): Boolean {
+    val underlyingType = inlineClassType.unsubstitutedUnderlyingType() ?: return false
+
+    return !inlineClassType.isMarkedNullable ||
+            !TypeUtils.isNullableType(underlyingType) && !KotlinBuiltIns.isPrimitiveType(underlyingType)
+}
diff --git a/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt b/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt
index c7b40b02031..4d2aef07e83 100644
--- a/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt
+++ b/core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt
@@ -16,10 +16,7 @@ import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
 import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType
-import org.jetbrains.kotlin.resolve.substitutedUnderlyingType
-import org.jetbrains.kotlin.resolve.unsubstitutedUnderlyingType
 import org.jetbrains.kotlin.types.*
-import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import org.jetbrains.kotlin.types.typeUtil.replaceArgumentsWithStarProjections
 import org.jetbrains.kotlin.types.typeUtil.representativeUpperBound
 import org.jetbrains.kotlin.utils.DO_NOTHING_3
@@ -238,66 +235,6 @@ private fun <T : Any> mapBuiltInType(
     return null
 }
 
-internal fun computeUnderlyingType(inlineClassType: KotlinType): KotlinType? {
-    if (!shouldUseUnderlyingType(inlineClassType)) return null
-
-    val descriptor = inlineClassType.unsubstitutedUnderlyingType()?.constructor?.declarationDescriptor ?: return null
-    return if (descriptor is TypeParameterDescriptor)
-        descriptor.representativeUpperBound
-    else
-        inlineClassType.substitutedUnderlyingType()
-}
-
-internal fun computeExpandedTypeForInlineClass(inlineClassType: KotlinType): KotlinType? =
-    computeExpandedTypeInner(inlineClassType, hashSetOf())
-
-internal fun computeExpandedTypeInner(kotlinType: KotlinType, visitedClassifiers: HashSet<ClassifierDescriptor>): KotlinType? {
-    val classifier = kotlinType.constructor.declarationDescriptor
-        ?: throw AssertionError("Type with a declaration expected: $kotlinType")
-    if (!visitedClassifiers.add(classifier)) return null
-
-    return when {
-        classifier is TypeParameterDescriptor ->
-            computeExpandedTypeInner(classifier.representativeUpperBound, visitedClassifiers)
-                ?.let { expandedUpperBound ->
-                    if (expandedUpperBound.isNullable() || !kotlinType.isMarkedNullable)
-                        expandedUpperBound
-                    else
-                        expandedUpperBound.makeNullable()
-                }
-
-        classifier is ClassDescriptor && classifier.isInline -> {
-            // kotlinType is the boxed inline class type
-
-            val underlyingType = kotlinType.substitutedUnderlyingType() ?: return null
-            val expandedUnderlyingType = computeExpandedTypeInner(underlyingType, visitedClassifiers) ?: return null
-            when {
-                !kotlinType.isNullable() -> expandedUnderlyingType
-
-                // Here inline class type is nullable. Apply nullability to the expandedUnderlyingType.
-
-                // Nullable types become inline class boxes
-                expandedUnderlyingType.isNullable() -> kotlinType
-
-                // Primitives become inline class boxes
-                KotlinBuiltIns.isPrimitiveType(expandedUnderlyingType) -> kotlinType
-
-                // Non-null reference types become nullable reference types
-                else -> expandedUnderlyingType.makeNullable()
-            }
-        }
-
-        else -> kotlinType
-    }
-}
-
-internal fun shouldUseUnderlyingType(inlineClassType: KotlinType): Boolean {
-    val underlyingType = inlineClassType.unsubstitutedUnderlyingType() ?: return false
-
-    return !inlineClassType.isMarkedNullable ||
-            !TypeUtils.isNullableType(underlyingType) && !KotlinBuiltIns.isPrimitiveType(underlyingType)
-}
-
 fun computeInternalName(
     klass: ClassDescriptor,
     typeMappingConfiguration: TypeMappingConfiguration<*> = TypeMappingConfigurationImpl,