diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
index bfdcba9c013..a503060981e 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/InlineCodegen.java
@@ -755,9 +755,6 @@ public class InlineCodegen extends CallGenerator {
         IncrementalCache incrementalCache = incrementalCompilationComponents.getIncrementalCache(target);
         String sourceFile = getClassFilePath(sourceDescriptor, incrementalCache);
         String targetFile = getSourceFilePath(targetDescriptor);
-        assert sourceFile != null: "No source file for inline fun: " + jvmSignature;
-        assert targetFile != null: "No target file for inline fun: " + jvmSignature;
-
         InlineRegistering inlineRegistering = incrementalCache.getInlineRegistering();
         inlineRegistering.registerInline(sourceFile, jvmSignature.toString(), targetFile);
     }
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/inlineCodegenUtils.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/inlineCodegenUtils.kt
index 3c46cfe2a06..400a0dc38db 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/inlineCodegenUtils.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/inlineCodegenUtils.kt
@@ -20,34 +20,32 @@ import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithSource
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.load.kotlin.KotlinJvmBinarySourceElement
 import org.jetbrains.kotlin.load.kotlin.VirtualFileKotlinClass
-import org.jetbrains.kotlin.load.kotlin.incremental.FileSourceElement
 import org.jetbrains.kotlin.load.kotlin.incremental.components.IncrementalCache
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
 import org.jetbrains.kotlin.resolve.source.PsiSourceElement
+import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedSimpleFunctionDescriptor
 
-public val FunctionDescriptor.sourceFilePath: String?
+public val FunctionDescriptor.sourceFilePath: String
     get() {
-        val source = source as? PsiSourceElement
-        val containingFile = source?.psi?.containingFile
-        return containingFile?.virtualFile?.canonicalPath
+        val source = source as PsiSourceElement
+        val containingFile = source.psi?.containingFile
+        return containingFile?.virtualFile?.canonicalPath!!
     }
 
-public fun FunctionDescriptor.getClassFilePath(cache: IncrementalCache): String? {
+public fun FunctionDescriptor.getClassFilePath(cache: IncrementalCache): String {
     val container = containingDeclaration as? DeclarationDescriptorWithSource
     val source = container?.source
 
     return when (source) {
-        is FileSourceElement ->
-            source.file.canonicalPath
         is KotlinJvmBinarySourceElement -> {
-            val kotlinClass = source.binaryClass as? VirtualFileKotlinClass
-            kotlinClass?.file?.canonicalPath
+            assert(this is DeserializedSimpleFunctionDescriptor) { "Expected DeserializedSimpleFunctionDescriptor, got: $this" }
+            val kotlinClass = source.binaryClass as VirtualFileKotlinClass
+            kotlinClass.file.canonicalPath!!
         }
         else -> {
-            val classId = InlineCodegenUtil.getContainerClassId(this)
-            val className = classId?.let { JvmClassName.byClassId(it) }?.internalName
-
-            if (className != null) cache.getClassFilePath(className) else null
+            val classId = InlineCodegenUtil.getContainerClassId(this)!!
+            val className = JvmClassName.byClassId(classId).internalName
+            cache.getClassFilePath(className)
         }
     }
 }
\ No newline at end of file
diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/FileSourceElement.kt b/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/FileSourceElement.kt
deleted file mode 100644
index cc3140dba3b..00000000000
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/FileSourceElement.kt
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.load.kotlin.incremental
-
-import org.jetbrains.kotlin.descriptors.SourceElement
-import java.io.File
-
-public class FileSourceElement(public val file: File) : SourceElement
\ No newline at end of file
diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackageFragmentProvider.kt b/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackageFragmentProvider.kt
index c7a19dd98b7..65433dc2c38 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackageFragmentProvider.kt
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackageFragmentProvider.kt
@@ -21,10 +21,8 @@ import org.apache.log4j.Logger
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
-import org.jetbrains.kotlin.descriptors.SourceElement
 import org.jetbrains.kotlin.descriptors.impl.PackageFragmentDescriptorImpl
 import org.jetbrains.kotlin.load.kotlin.ModuleMapping
-import org.jetbrains.kotlin.load.kotlin.PackageClassUtils
 import org.jetbrains.kotlin.load.kotlin.PackagePartClassUtils
 import org.jetbrains.kotlin.load.kotlin.incremental.components.IncrementalCache
 import org.jetbrains.kotlin.modules.Module
@@ -44,7 +42,6 @@ import org.jetbrains.kotlin.serialization.jvm.JvmProtoBufUtil
 import org.jetbrains.kotlin.storage.NotNullLazyValue
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.utils.addToStdlib.singletonOrEmptyList
-import java.io.File
 import java.util.*
 
 public class IncrementalPackageFragmentProvider(
@@ -100,14 +97,6 @@ public class IncrementalPackageFragmentProvider(
         public val target: Module
             get() = this@IncrementalPackageFragmentProvider.target
 
-        private val sourceElement: SourceElement by lazy {
-            val incrementalCache = this@IncrementalPackageFragmentProvider.incrementalCache
-            val classId = PackageClassUtils.getPackageClassId(fqName)
-            val className = JvmClassName.byClassId(classId)
-            val classFilePath = incrementalCache.getClassFilePath(className.internalName)
-            FileSourceElement(File(classFilePath))
-        }
-
         val memberScope: NotNullLazyValue<JetScope> = storageManager.createLazyValue {
             if (fqName !in fqNamesToLoad) {
                 JetScope.Empty
@@ -147,8 +136,6 @@ public class IncrementalPackageFragmentProvider(
             }
         }
 
-        override fun getSource(): SourceElement = sourceElement
-
         override fun getMemberScope(): JetScope = memberScope()
 
         private inner class IncrementalPackageScope(val packageData: PackageData) : DeserializedPackageMemberScope(