diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/classFileUtils.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/classFileUtils.kt
index 08bbde1bb92..ea11f4e1e5a 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/classFileUtils.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/classFileUtils.kt
@@ -36,7 +36,7 @@ private fun List<PackageParts>.addCompiledParts(state: GenerationState): List<Pa
     val incrementalCache = state.incrementalCacheForThisTarget ?: return this
     val moduleMappingData = incrementalCache.getModuleMappingData() ?: return this
 
-    val mapping = ModuleMapping.create(moduleMappingData)
+    val mapping = ModuleMapping.create(moduleMappingData, "<incremental>")
 
     incrementalCache.getObsoletePackageParts().forEach {
         val i = it.lastIndexOf('/')
diff --git a/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/JvmPackagePartProvider.kt b/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/JvmPackagePartProvider.kt
index 9554078558c..1050dc4f331 100644
--- a/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/JvmPackagePartProvider.kt
+++ b/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/JvmPackagePartProvider.kt
@@ -16,7 +16,6 @@
 
 package org.jetbrains.kotlin.cli.jvm.compiler
 
-import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.util.SmartList
 import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot
 import org.jetbrains.kotlin.config.JVMConfigurationKeys
@@ -61,13 +60,13 @@ class JvmPackagePartProvider(val env: KotlinCoreEnvironment) : PackagePartProvid
         loadedModules.addAll(relevantRoots.mapNotNull {
             it.findChild("META-INF")
         }.flatMap {
-            it.children.filter<VirtualFile> { it.name.endsWith(ModuleMapping.MAPPING_FILE_EXT) }
-        }.map {
+            it.children.filter { it.name.endsWith(ModuleMapping.MAPPING_FILE_EXT) }
+        }.map { file ->
             try {
-                ModuleMapping.create(it.contentsToByteArray())
+                ModuleMapping.create(file.contentsToByteArray(), file.toString())
             }
             catch (e: EOFException) {
-                throw RuntimeException("Error on reading package parts for '$packageFqName' package in '$it', roots: $notLoadedRoots", e)
+                throw RuntimeException("Error on reading package parts for '$packageFqName' package in '$file', roots: $notLoadedRoots", e)
             }
         })
     }
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 6384523d7df..b1b9fbd1db4 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
@@ -90,7 +90,7 @@ class IncrementalPackageFragmentProvider(
                 MemberScope.Empty
             }
             else {
-                val moduleMapping = incrementalCache.getModuleMappingData()?.let { ModuleMapping.create(it) }
+                val moduleMapping = incrementalCache.getModuleMappingData()?.let { ModuleMapping.create(it, "<incremental>") }
 
                 val actualPackagePartFiles =
                         moduleMapping?.findPackageParts(fqName.asString())?.let {
diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackagePartProvider.kt b/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackagePartProvider.kt
index 2f0cb632a6b..8517b683f6c 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackagePartProvider.kt
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackagePartProvider.kt
@@ -28,7 +28,11 @@ internal class IncrementalPackagePartProvider private constructor(
         incrementalCaches: List<IncrementalCache>,
         storageManager: StorageManager
 ) : PackagePartProvider {
-    private val moduleMappings = storageManager.createLazyValue { incrementalCaches.map { ModuleMapping.create(it.getModuleMappingData()) } }
+    private val moduleMappings = storageManager.createLazyValue {
+        incrementalCaches.map { cache ->
+            ModuleMapping.create(cache.getModuleMappingData(), "<incremental>")
+        }
+    }
 
     override fun findPackageParts(packageFqName: String): List<String> {
         return (moduleMappings().mapNotNull { it.findPackageParts(packageFqName) }.flatMap { it.parts } +
diff --git a/core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/ModuleMapping.kt b/core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/ModuleMapping.kt
index c3cfc99a739..f0d8cfb51f4 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/ModuleMapping.kt
+++ b/core/descriptor.loader.java/src/org/jetbrains/kotlin/load/kotlin/ModuleMapping.kt
@@ -20,20 +20,21 @@ import org.jetbrains.kotlin.serialization.jvm.JvmPackageTable
 import java.io.ByteArrayInputStream
 import java.io.DataInputStream
 
-class ModuleMapping private constructor(val packageFqName2Parts: Map<String, PackageParts>) {
-
+class ModuleMapping private constructor(val packageFqName2Parts: Map<String, PackageParts>, private val debugName: String) {
     fun findPackageParts(packageFqName: String): PackageParts? {
         return packageFqName2Parts[packageFqName]
     }
 
+    override fun toString() = debugName
+
     companion object {
         @JvmField
         val MAPPING_FILE_EXT: String = "kotlin_module"
 
         @JvmField
-        val EMPTY: ModuleMapping = ModuleMapping(emptyMap())
+        val EMPTY: ModuleMapping = ModuleMapping(emptyMap(), "EMPTY")
 
-        fun create(proto: ByteArray? = null): ModuleMapping {
+        fun create(proto: ByteArray?, debugName: String?): ModuleMapping {
             if (proto == null) {
                 return EMPTY
             }
@@ -52,7 +53,7 @@ class ModuleMapping private constructor(val packageFqName2Parts: Map<String, Pac
                             packageParts.parts.add(it)
                         }
                     }
-                    return ModuleMapping(packageFqNameParts)
+                    return ModuleMapping(packageFqNameParts, debugName ?: "<unknown>")
                 }
             }
             else {
diff --git a/core/descriptors.runtime/src/org/jetbrains/kotlin/load/kotlin/reflect/RuntimePackagePartProvider.kt b/core/descriptors.runtime/src/org/jetbrains/kotlin/load/kotlin/reflect/RuntimePackagePartProvider.kt
index 4dcd40eda9c..8c9a66cf23f 100644
--- a/core/descriptors.runtime/src/org/jetbrains/kotlin/load/kotlin/reflect/RuntimePackagePartProvider.kt
+++ b/core/descriptors.runtime/src/org/jetbrains/kotlin/load/kotlin/reflect/RuntimePackagePartProvider.kt
@@ -25,8 +25,9 @@ class RuntimePackagePartProvider(private val classLoader: ClassLoader) : Package
 
     fun registerModule(moduleName: String) {
         val mapping = try {
-            classLoader.getResourceAsStream("META-INF/$moduleName.${ModuleMapping.MAPPING_FILE_EXT}")?.use { stream ->
-                ModuleMapping.create(stream.readBytes())
+            val resourcePath = "META-INF/$moduleName.${ModuleMapping.MAPPING_FILE_EXT}"
+            classLoader.getResourceAsStream(resourcePath)?.use { stream ->
+                ModuleMapping.create(stream.readBytes(), resourcePath)
             }
         }
         catch (e: Exception) {
diff --git a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/vfilefinder/moduleMappingIndexes.kt b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/vfilefinder/moduleMappingIndexes.kt
index 1a3fdc711d6..b673ff20cbe 100644
--- a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/vfilefinder/moduleMappingIndexes.kt
+++ b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/vfilefinder/moduleMappingIndexes.kt
@@ -77,17 +77,16 @@ object KotlinModuleMappingIndex : FileBasedIndexExtension<String, PackageParts>(
     override fun getVersion(): Int = 1
 
     override fun getIndexer(): DataIndexer<String, PackageParts, FileContent> {
-        return object : DataIndexer<String, PackageParts, FileContent> {
-            override fun map(inputData: FileContent): Map<String, PackageParts> {
-                val content = inputData.content
-                try {
-                    val moduleMapping = ModuleMapping.create(content)
-                    return moduleMapping.packageFqName2Parts
-                } catch(e : Exception) {
-                    throw RuntimeException("Error on indexing ${inputData.file.path}", e)
-                }
+        return DataIndexer<String, PackageParts, FileContent> { inputData ->
+            val content = inputData.content
+            val file = inputData.file
+            try {
+                val moduleMapping = ModuleMapping.create(content, file.toString())
+                return@DataIndexer moduleMapping.packageFqName2Parts
+            }
+            catch(e: Exception) {
+                throw RuntimeException("Error on indexing $file", e)
             }
         }
     }
 }
-