Unreal Engine Issues and Bug Tracker (UE-51260)

Description

When you add an Interface to a Blueprint that contains a variable with the same name as one of the Interface's functions, the editor will crash upon compiling the blueprint. In 4.16, this only caused an error to occur and for the compilation of the blueprint to fail.

The error thrown in 4.16 is as follows:

 Error Interface name collision in blueprint: Blueprint /Game/NewBlueprint.NewBlueprint, interface: BlueprintGeneratedClass /Game/NewInterface.NewInterface_C, name: TestName

Error Name collision - function and property have the same name - 'TestName'.  <None>

Regression?: Yes
This crash did not occur in 4.16.3
This crash does occur in 4.17.2

Steps to Reproduce

Create a new Blueprint Interface
Rename the first function in it to TestName
Compile/Save the Interface
Create a new Blueprint Actor
Add a new variable also called TestName
In the Class Defaults, add the Interface made in step 1
Compile the Blueprint Actor
Result: The Editor crashes
Expected: An error is thrown, saying that there is a collision in the two names.

Callstack

Fatal error: [File:D:\Build\++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 2310] Objects have the same fully qualified name but different paths. New Object: Function /Game/MyActor.SKEL_MyActor_C.HelloWorld Existing Object: BoolProperty /Game/MyActor.SKEL_MyActor_C:HelloWorld

UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:414]
UE4Editor_CoreUObject!StaticAllocateObject() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2305]
UE4Editor_CoreUObject!StaticConstructObject_Internal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:3145]
UE4Editor_Kismet!<lambda_13e5a315ee63cc970f4093a0b1c24681>::operator()() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:1529]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::FastGenerateSkeletonClass() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:1892]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::FlushCompilationQueueImpl() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:577]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::CompileSynchronouslyImpl() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprintcompilationmanager.cpp:198]
UE4Editor_UnrealEd!FKismetEditorUtilities::CompileBlueprint() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:745]
UE4Editor_Kismet!FBlueprintEditor::Compile() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:3181]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper<void> __cdecl(void)>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:327]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl(void)>::ExecuteIfSafe() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:434]
UE4Editor_Slate!FUICommandList::ExecuteAction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:97]
UE4Editor_Slate!SToolBarButtonBlock::OnClicked() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\multibox\stoolbarbuttonblock.cpp:300]
UE4Editor_Slate!TMemberFunctionCaller<SToolBarButtonBlock,FReply (__cdecl SToolBarButtonBlock::*)(void) __ptr64>::operator()<>() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstanceinterface.h:165]
UE4Editor_Slate!UE4Tuple_Private::TTupleImpl<TIntegerSequence<unsigned int> >::ApplyAfter<TMemberFunctionCaller<SToolBarButtonBlock,FReply (__cdecl SToolBarButtonBlock::*)(void) __ptr64> >() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\templates\tuple.h:497]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SToolBarButtonBlock,0,FReply __cdecl(void)>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:327]
UE4Editor_Slate!TBaseDelegate<FReply>::Execute() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:537]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:282]
UE4Editor_Slate!<lambda_1002768c627006711ef2f351a87ec0e7>::operator()() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5263]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_1002768c627006711ef2f351a87ec0e7> >() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:234]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5252]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5750]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5730]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1725]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2171]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:888]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:725]
user32
user32
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:129]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3220]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build\++ue4+release-4.18+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:253]
kernel32
ntdll

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Fixed

Component	UE - Gameplay - Blueprint Compiler
Affects Versions	4.17, 4.18, 4.19
Target Fix	4.18

Fix Commit	3687527
Release Commit	3687527

Created	Oct 13, 2017
Resolved	Oct 13, 2017
Updated	Apr 27, 2018

View Jira Issue

UE-51260

Crash upon adding an Interface to a Blueprint that has a function name that matches the name of a variable in the Blueprint.

Crash upon adding an Interface to a Blueprint that has a function name that matches the name of a variable in the Blueprint.

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