diff --git a/idea/src/org/jetbrains/kotlin/idea/debugger/JetPositionManager.kt b/idea/src/org/jetbrains/kotlin/idea/debugger/JetPositionManager.kt
index 1d1b00b0838..df41d245c63 100644
--- a/idea/src/org/jetbrains/kotlin/idea/debugger/JetPositionManager.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/debugger/JetPositionManager.kt
@@ -300,7 +300,7 @@ public class JetPositionManager(private val myDebugProcess: DebugProcess) : Mult
 
         return classNameForPositionAndInlinedOnes(position).map {
             className -> myDebugProcess.getRequestsManager().createClassPrepareRequest(requestor, className.replace('/', '.'))
-        }
+        }.filterNotNull()
     }
 
     TestOnly