Description

When a custom event has an input whose type is a reference to an object (Actor-Reference, Player Controller - Reference, etc) and is set to pass-by-reference, passing a reference to the "self" blueprint into the custom event call causes the editor to crash.

Note:
This was discovered because dragging a node input to the custom event node will add an input that is set to pass-by-reference by default

Steps to Reproduce
  1. Open UE4 Editor
  2. Add blueprint based on Actor (MyActor)
  3. Create custom event node (MyCustomEvent)
  4. Add input pin (TestInput)
  5. Set TestInput type to Actor-Reference and check the box for Pass-by-reference
  6. Add call to MyCustomEvent
  7. Add Self reference node
  8. Wire Begin Play into MyCustomEvent and Self reference into TestInput
  9. Add instance of MyActor to the level
  10. PIE

Result:
Editor crashes immediately after starting PIE

Expected:
Self reference cannot be connected to a pin that is pass-by-reference

Callstack
LoginId:7156c35640f86204e61b8383f45dee17
EpicAccountId:e8c7fa630b6440f69a25a2c64d6c482c

Access violation - code c0000005 (first/second chance not available)

UE4Editor_CoreUObject!UObject::execSelf() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2113]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:788]
UE4Editor_CoreUObject!UObject::execVirtualFunction() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2255]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:948]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:845]
UE4Editor_CoreUObject!UObject::execVirtualFunction() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2255]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:948]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4525]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1318]
UE4Editor_Engine!AActor::ProcessEvent() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\actor.cpp:678]
UE4Editor_Engine!FInputActionHandlerDynamicSignature::Execute() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\classes\components\inputcomponent.h:108]
UE4Editor_Engine!FInputActionUnifiedDelegate::Execute() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\classes\components\inputcomponent.h:204]
UE4Editor_Engine!UPlayerInput::ProcessInputStack() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\userinterface\playerinput.cpp:1243]
UE4Editor_Engine!APlayerController::ProcessPlayerInput() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\playercontroller.cpp:2376]
UE4Editor_Engine!APlayerController::TickPlayerInput() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\playercontroller.cpp:4051]
UE4Editor_Engine!APlayerController::PlayerTick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\playercontroller.cpp:2039]
UE4Editor_Engine!APlayerController::TickActor() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\playercontroller.cpp:4133]
UE4Editor_Engine!FActorTickFunction::ExecuteTick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\actor.cpp:125]
UE4Editor_Engine!FTickFunctionTask::DoTask() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:269]
UE4Editor_Engine!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:883]
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:954]
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:701]
UE4Editor_Core!FTaskGraphImplementation::WaitUntilTasksComplete() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:1798]
UE4Editor_Engine!FTickTaskSequencer::ReleaseTickGroup() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:538]
UE4Editor_Engine!FTickTaskManager::RunTickGroup() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:1450]
UE4Editor_Engine!UWorld::RunTickGroup() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:758]
UE4Editor_Engine!UWorld::Tick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:1373]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1630]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:391]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3025]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll

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Duplicate
ComponentUE - Gameplay - Blueprint
Affects Versions4.14.34.15
Target Fix4.16
CreatedFeb 7, 2017
ResolvedMar 6, 2017
UpdatedApr 27, 2018