Crash removing a pin from an in-use struct, and then undo/redo

REGRESSION No

Crash occurs when the user deletes a pin from a struct that is in use, then performs undo and redo on the deleting.

1. Open QAGame in editor.
2. Create a new blueprint and open it.
3. Add a variable based on a struct (AECategories).
4. Add the variable to the level as a get.
5. Right-click the pin and select Split Struct Pin.
6. Open the struct you are using.
7. Delete a pin.
8. Undo/Redo the deleting.

RESULT

Crash.

Assertion failed: !PinRef->bWasTrashed [Link Removed] [Line: 1562]

KERNELBASE.dll!0x00000000FD73A06D
UE4Editor-Core.dll!FOutputDeviceWindowsError::Serialize() [d:\framework\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:120]
UE4Editor-Core.dll!FOutputDevice::Logf__VA() [d:\framework\engine\source\runtime\core\private\misc\outputdevice.cpp:70]
UE4Editor-Core.dll!FDebug::AssertFailed() [d:\framework\engine\source\runtime\core\private\misc\assertionmacros.cpp:349]
UE4Editor-Engine.dll!UEdGraphPin::SerializePin() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:1563]
UE4Editor-Engine.dll!UEdGraphPin::SerializePinArray() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:1513]
UE4Editor-Engine.dll!UEdGraphPin::Serialize() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:1366]
UE4Editor-Engine.dll!UEdGraphPin::SerializePin() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:1671]
UE4Editor-Engine.dll!UEdGraphPin::SerializePinArray() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphpin.cpp:1513]
UE4Editor-Engine.dll!UEdGraphNode::Serialize() [d:\framework\engine\source\runtime\engine\private\edgraph\edgraphnode.cpp:433]
UE4Editor-BlueprintGraph.dll!UK2Node::Serialize() [d:\framework\engine\source\editor\blueprintgraph\private\k2node.cpp:114]
UE4Editor-BlueprintGraph.dll!UK2Node_Variable::Serialize() [d:\framework\engine\source\editor\blueprintgraph\private\k2node_variable.cpp:29]
UE4Editor-CoreUObject.dll!StaticDuplicateObjectEx() [d:\framework\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2022]
UE4Editor-UnrealEd.dll!FEdGraphUtilities::CloneGraph() [d:\framework\engine\source\editor\unrealed\private\edgraphutilities.cpp:215]
UE4Editor-UnrealEd.dll!FEdGraphUtilities::CloneAndMergeGraphIn() [d:\framework\engine\source\editor\unrealed\private\edgraphutilities.cpp:258]
UE4Editor-KismetCompiler.dll!FKismetCompilerContext::MergeUbergraphPagesIn() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompiler.cpp:2777]
UE4Editor-KismetCompiler.dll!FKismetCompilerContext::CreateAndProcessUbergraph() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompiler.cpp:3034]
UE4Editor-KismetCompiler.dll!FKismetCompilerContext::CreateFunctionList() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompiler.cpp:3573]
UE4Editor-KismetCompiler.dll!FKismetCompilerContext::CompileClassLayout() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompiler.cpp:3832]
UE4Editor-KismetCompiler.dll!FKismet2CompilerModule::CompileBlueprintInner() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompilermodule.cpp:130]
UE4Editor-KismetCompiler.dll!FKismet2CompilerModule::CompileBlueprint() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompilermodule.cpp:231]
UE4Editor-UnrealEd.dll!FBlueprintEditorUtils::MarkBlueprintAsStructurallyModified() [d:\framework\engine\source\editor\unrealed\private\kismet2\blueprinteditorutils.cpp:2074]
UE4Editor-KismetCompiler.dll!FUserDefinedStructureCompilerUtils::CompileStruct() [d:\framework\engine\source\editor\kismetcompiler\private\userdefinedstructurecompilerutils.cpp:447]
UE4Editor-KismetCompiler.dll!FKismet2CompilerModule::CompileStructure() [d:\framework\engine\source\editor\kismetcompiler\private\kismetcompilermodule.cpp:179]
UE4Editor-UnrealEd.dll!FStructureEditorUtils::CompileStructure() [d:\framework\engine\source\editor\unrealed\private\kismet2\structureeditorutils.cpp:570]
UE4Editor-UnrealEd.dll!FStructureEditorUtils::OnStructureChanged() [d:\framework\engine\source\editor\unrealed\private\kismet2\structureeditorutils.cpp:582]
UE4Editor-UnrealEd.dll!UUserDefinedStructEditorData::PostEditUndo() [d:\framework\engine\source\editor\unrealed\private\userdefinedstructeditordata.cpp:102]
UE4Editor-UnrealEd.dll!FTransaction::Apply() [d:\framework\engine\source\editor\unrealed\private\editortransaction.cpp:497]
UE4Editor-UnrealEd.dll!UTransBuffer::Redo() [d:\framework\engine\source\editor\unrealed\private\editortransaction.cpp:901]
UE4Editor-UnrealEd.dll!UEditorEngine::Exec_Transaction() [d:\framework\engine\source\editor\unrealed\private\editorserver.cpp:5117]
UE4Editor-UnrealEd.dll!UEditorEngine::Exec() [d:\framework\engine\source\editor\unrealed\private\editorserver.cpp:5564]
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Exec() [d:\framework\engine\source\editor\unrealed\private\unrealedsrv.cpp:672]
UE4Editor-MainFrame.dll!FMainFrameActionCallbacks::ExecuteExecCommand() [d:\framework\engine\source\editor\mainframe\private\frame\mainframeactions.cpp:973]
UE4Editor-MainFrame.dll!TBaseStaticDelegateInstance<void __cdecl(void),FString>::ExecuteIfSafe() [d:\framework\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:1027]
UE4Editor-Slate.dll!FUICommandList::ConditionalProcessCommandBindings() [d:\framework\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:216]
UE4Editor-Slate.dll!FUICommandList::ProcessCommandBindings() [d:\framework\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:160]
UE4Editor-MainFrame.dll!FMainFrameActionCallbacks::OnUnhandledKeyDownEvent() [d:\framework\engine\source\editor\mainframe\private\frame\mainframeactions.cpp:211]
UE4Editor-MainFrame.dll!UE4Tuple_Private::TTupleImpl<TIntegerSequence<unsigned int> >::ApplyAfter<FReply (__cdecl*const & __ptr64)(FKeyEvent const & __ptr64),FKeyEvent const & __ptr64>() [d:\framework\engine\source\runtime\core\public\templates\tuple.h:497]
UE4Editor-MainFrame.dll!TBaseStaticDelegateInstance<FReply __cdecl(FKeyEvent const & __ptr64)>::Execute() [d:\framework\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:958]
UE4Editor-Slate.dll!TBaseDelegate<FReply,FKeyEvent const & __ptr64>::Execute() [d:\framework\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:537]
UE4Editor-Slate.dll!FSlateApplication::ProcessKeyDownEvent() [d:\framework\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4679]
UE4Editor-Slate.dll!FSlateApplication::OnKeyDown() [d:\framework\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4579]
UE4Editor-Core.dll!FWindowsApplication::ProcessDeferredMessage() [d:\framework\engine\source\runtime\core\private\windows\windowsapplication.cpp:1534]
UE4Editor-Core.dll!FWindowsApplication::DeferMessage() [d:\framework\engine\source\runtime\core\private\windows\windowsapplication.cpp:2122]
UE4Editor-Core.dll!FWindowsApplication::ProcessMessage() [d:\framework\engine\source\runtime\core\private\windows\windowsapplication.cpp:862]
UE4Editor-Core.dll!FWindowsApplication::AppWndProc() [d:\framework\engine\source\runtime\core\private\windows\windowsapplication.cpp:709]
USER32.dll!0x00000000778F9BBD
USER32.dll!0x00000000778F98C2
UE4Editor-Core.dll!FWindowsPlatformMisc::PumpMessages() [d:\framework\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:1009]
UE4Editor.exe!FEngineLoop::Tick() [d:\framework\engine\source\runtime\launch\private\launchengineloop.cpp:3089]
UE4Editor.exe!GuardedMain() [d:\framework\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor.exe!GuardedMainWrapper() [d:\framework\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor.exe!WinMain() [d:\framework\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor.exe!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32.dll!0x00000000777D59CD
ntdll.dll!0x0000000077A0A561
ntdll.dll!0x0000000077A0A561