This is a common crash occurring for users in 4.16
User Descriptions
Source Context
266 /** 267 * @return true if this object is of the specified type. 268 */ 269 #if UCLASS_FAST_ISA_COMPARE_WITH_OUTERWALK || UCLASS_FAST_ISA_IMPL == UCLASS_ISA_OUTERWALK 270 bool UObjectBaseUtility::IsA( const UClass* SomeBase ) const 271 { 272 UE_CLOG(!SomeBase, LogObj, Fatal, TEXT("IsA(NULL) cannot yield meaningful results")); 273 274 UClass* ThisClass = GetClass(); 275 276 bool bOldResult = false; 277 ***** for ( UClass* TempClass=ThisClass; TempClass; TempClass=TempClass->GetSuperClass() ) 278 { 279 if ( TempClass == SomeBase ) 280 { 281 bOldResult = true; 282 break; 283 } 284 }
repro steps currently unknown
Access violation - code c0000005 (first/second chance not available) UE4Editor_CoreUObject!UObjectBaseUtility::IsA() [uobjectbaseutility.cpp:278] UE4Editor_Engine!FUniformExpressionSet::CreateUniformBuffer() [materialuniformexpressions.cpp:370] UE4Editor_Engine!FMaterialRenderProxy::EvaluateUniformExpressions() [materialshared.cpp:1962] UE4Editor_Renderer!FMaterialShader::SetParameters<FRHIVertexShader * __ptr64>() [shaderbaseclasses.cpp:236] UE4Editor_Renderer!TBasePassVertexShaderPolicyParamType<FUniformLightMapPolicyShaderParametersType>::SetParameters() [basepassrendering.h:377] UE4Editor_Renderer!TBasePassDrawingPolicy<FUniformLightMapPolicy>::SetSharedState() [basepassrendering.h:1127] UE4Editor_Renderer!FDrawBasePassDynamicMeshAction::Process<FUniformLightMapPolicy>() [basepassrendering.cpp:610] UE4Editor_Renderer!ProcessBasePassMesh<FDrawBasePassDynamicMeshAction>() [basepassrendering.h:1557] UE4Editor_Renderer!FBasePassOpaqueDrawingPolicyFactory::DrawDynamicMesh() [basepassrendering.cpp:665] UE4Editor_Renderer!FRendererModule::DrawTileMesh() [renderer.cpp:151] UE4Editor_Engine!FTileRenderer::DrawTile() [tilerendering.cpp:197] UE4Editor_Engine!FCanvasTileRendererItem::Render_RenderThread() [tilerendering.cpp:263] UE4Editor_Engine!FCanvas::Flush_RenderThread() [canvas.cpp:702] UE4Editor_GraphEditor!FPreviewElement::DrawRenderThread() [sgraphnodematerialbase.cpp:247] UE4Editor_SlateRHIRenderer!FSlateRHIRenderingPolicy::DrawElements() [slaterhirenderingpolicy.cpp:707] UE4Editor_SlateRHIRenderer!FSlateRHIRenderer::DrawWindow_RenderThread() [slaterhirenderer.cpp:766] UE4Editor_SlateRHIRenderer!TGraphTask<TEnqueueUniqueRenderCommandType<`FSlateRHIRenderer::DrawWindows_Private'::`29'::SlateDrawWindowsCommandName,<lambda_43e86ee7c51f39979e9a39d40b280024> > >::ExecuteTask() [taskgraphinterfaces.h:883] UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [taskgraph.cpp:954] UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [taskgraph.cpp:701] UE4Editor_RenderCore!RenderingThreadMain() [renderingthread.cpp:327] UE4Editor_RenderCore!FRenderingThread::Run() [renderingthread.cpp:461] UE4Editor_Core!FRunnableThreadWin::Run() [windowsrunnablethread.cpp:76]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-47258 in the post.