diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/NameGenerator.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/NameGenerator.java
index 54d0f7601d3..da85f8bdc75 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/NameGenerator.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/NameGenerator.java
@@ -23,7 +23,8 @@ public class NameGenerator {
 
     private final String ownerMethod;
 
-    private int nextIndex = 1;
+    private int nextLambdaIndex = 1;
+    private int nextWhenIndex = 1;
 
     private final Map<String, NameGenerator> subGenerators = new HashMap<String, NameGenerator>();
 
@@ -32,7 +33,11 @@ public class NameGenerator {
     }
 
     public String genLambdaClassName() {
-        return ownerMethod + "$" + nextIndex++;
+        return ownerMethod + "$" + nextLambdaIndex++;
+    }
+
+    public String genWhenClassNamePrefix() {
+        return ownerMethod + "$" + nextWhenIndex++;
     }
 
     public NameGenerator subGenerator(String inliningMethod) {
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/TransformationInfo.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/TransformationInfo.kt
index 2d1f329c6ec..470a51314d4 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/TransformationInfo.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/inline/TransformationInfo.kt
@@ -43,7 +43,7 @@ class WhenMappingTransformationInfo(
 ) : TransformationInfo {
 
     override val newClassName by lazy {
-        nameGenerator.genLambdaClassName() + oldClassName.substringAfterLast("/")
+        nameGenerator.genWhenClassNamePrefix() + TRANSFORMED_WHEN_MAPPING_MARKER + oldClassName.substringAfterLast("/").substringAfterLast(TRANSFORMED_WHEN_MAPPING_MARKER)
     }
 
     override fun shouldRegenerate(sameModule: Boolean): Boolean {
@@ -57,6 +57,10 @@ class WhenMappingTransformationInfo(
     override fun createTransformer(inliningContext: InliningContext, sameModule: Boolean): ObjectTransformer<*> {
         return WhenMappingTransformer(this, inliningContext)
     }
+
+    companion object {
+        const val TRANSFORMED_WHEN_MAPPING_MARKER = "\$wm$"
+    }
 }
 
 class AnonymousObjectTransformationInfo internal constructor(