Unreal Engine Issues and Bug Tracker (UE-159821)

Description

This is not a regression. Tested in //UE4/Release-4.27 CL18319896

Crash when recombining Value Pin after swapping Target Wild Card pin from a Vector2D to a Vector on a Set By-Ref Var node.

Steps to Reproduce

Create or open any project
Create a new Blueprint Actor
Create a Vector variable
Create a Vector2D variable
In the Event Graph create a 'Set By-Ref Var' node
Get a reference to the Vector2D variable then connect it to the 'Target' pin
Right click the 'Value' input pin then select 'Split Struct Pin'
Disconnect the Vector2D from the 'Set By-Ref Var' node
Get a reference to the Vector variable then connect it to the 'Target' pin
Right click the 'Value' input pin then select 'Recombine Struct Pin'

Expected Results:
The pin recombines, but is now a Vector.

Actual Results:
The editor crashes:

Array index out of bounds: 2 from an array of size 2

Callstack

Error: === Critical error: ===
Error: 
Error: Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 691] 
Error: Array index out of bounds: 2 from an array of size 2
Error: 
Error: 
Error: [Callstack] 0x00007ff9298f454f UnrealEditor-BlueprintGraph.dll!UEdGraphSchema_K2::RecombinePin() [D:\build\++UE5\Sync\Engine\Source\Editor\BlueprintGraph\Private\EdGraphSchema_K2.cpp:7245]
Error: [Callstack] 0x00007ff92cc12fe0 UnrealEditor-Kismet.dll!FBlueprintEditor::OnRecombineStructPin() [D:\build\++UE5\Sync\Engine\Source\Editor\Kismet\Private\BlueprintEditor.cpp:4641]
Error: [Callstack] 0x00007ff92cbf120c UnrealEditor-Kismet.dll!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,1,void __cdecl(void),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:307]
Error: [Callstack] 0x00007ff93893b158 UnrealEditor-Slate.dll!FUICommandList::ExecuteAction() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Commands\UICommandList.cpp:99]
Error: [Callstack] 0x00007ff938a1d551 UnrealEditor-Slate.dll!SMenuEntryBlock::OnClicked() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:1148]
Error: [Callstack] 0x00007ff938a1e520 UnrealEditor-Slate.dll!SMenuEntryBlock::OnMenuItemButtonClicked() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:1108]
Error: [Callstack] 0x00007ff938a00944 UnrealEditor-Slate.dll!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,1,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:290]
Error: [Callstack] 0x00007ff938a9ba3b UnrealEditor-Slate.dll!SButton::ExecuteOnClick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:464]
Error: [Callstack] 0x00007ff938ac2df6 UnrealEditor-Slate.dll!SButton::OnMouseButtonUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:389]
Error: [Callstack] 0x00007ff938a1e60c UnrealEditor-Slate.dll!SMenuEntryButton::OnMouseButtonUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:434]
Error: [Callstack] 0x00007ff938864034 UnrealEditor-Slate.dll!<lambda_51e270ca99ea7ce852539efd04dd453f>::operator()() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4959]
Error: [Callstack] 0x00007ff938846fc6 UnrealEditor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_51e270ca99ea7ce852539efd04dd453f> >() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:405]
Error: [Callstack] 0x00007ff9388c02ee UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4945]
Error: [Callstack] 0x00007ff9388a91b1 UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5493]
Error: [Callstack] 0x00007ff93889d5dc UnrealEditor-Slate.dll!FSlateApplication::OnMouseUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5458]
Error: [Callstack] 0x00007ff99101a92e UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2210]
Error: [Callstack] 0x00007ff991009247 UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2699]
Error: [Callstack] 0x00007ff99101ce51 UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1078]
Error: [Callstack] 0x00007ff9910049a7 UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:916]
Error: [Callstack] 0x00007ff9cccb5c0d USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ff9cccb5602 USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ff99101e148 UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:138]
Error: [Callstack] 0x00007ff7216e7114 UnrealEditor.exe!FEngineLoop::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5139]
Error: [Callstack] 0x00007ff721700d9c UnrealEditor.exe!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:183]
Error: [Callstack] 0x00007ff721700e8a UnrealEditor.exe!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:147]
Error: [Callstack] 0x00007ff721703c4d UnrealEditor.exe!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:283]
Error: [Callstack] 0x00007ff721715564 UnrealEditor.exe!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:330]
Error: [Callstack] 0x00007ff721718736 UnrealEditor.exe!__scrt_common_main_seh() [d:\a01\_work\6\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
Error: [Callstack] 0x00007ff9ccb47c24 KERNEL32.DLL!UnknownFunction []
Error: [Callstack] 0x00007ff9ce54d721 ntdll.dll!UnknownFunction []

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Fixed

Component	UE - Gameplay - Blueprint
Affects Versions	5.0.3
Target Fix	5.1

Fix Commit	21209234
Main Commit	21209234

Created	Jul 18, 2022
Resolved	Jul 21, 2022
Updated	Feb 14, 2023