Crash on inputting Scalar Value in Grass Material Node

Crash occurs when inputting a Scalar Parameter into the New to 4,8 Grass Node.

Also reproduced in Main Promotable-CL-2535351

1. Open QAGame Editor
2. Create a New Material
3. Add the LandscapeGrassOutput Node
4. Add a Scalar Parameter
5. Attach the Scalar Parameter to the Grass Node

RESULTS: Editor Crashes

EXPECTED: NO Crash, if not possible a warning message.

Assertion failed: !CodeChunks[ResultIndex].UniformExpression || CodeChunks[ResultIndex].UniformExpression->IsConstant() [Link Removed] [Line: 817]

KERNELBASE.dll

{0x000007fefd43940d}

+ 0 bytes
UE4Editor-Core.dll!FOutputDeviceWindowsError::Serialize()

{0x000007fecf6a5a3f}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FOutputDevice::Logf__VA()

{0x000007fecf55f1e8}

+ 159 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FDebug::AssertFailed()

{0x000007fecf5303c2}

+ 65 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FHLSLMaterialTranslator::GetFixedParameterCode()

{0x000007fecae86a0a}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FHLSLMaterialTranslator::CustomOutput()

{0x000007fecae727ef}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Landscape.dll!UMaterialExpressionLandscapeGrassOutput::Compile()

{0x000007fecd5a80bc}

+ 180 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FHLSLMaterialTranslator::Translate()

{0x000007fecaec6642}

+ 22 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FMaterial::BeginCompileShaderMap()

{0x000007fecae64a55}

+ 12 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FMaterial::CacheShaders()

{0x000007fecae661b7}

+ 25 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!FMaterial::CacheShaders()

{0x000007fecae665f6}

+ 20 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!UMaterial::CacheShadersForResources()

{0x000007fecadd4162}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!UMaterial::CacheResourceShadersForRendering()

{0x000007fecadd3e4b}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Engine.dll!UMaterial::PostEditChangeProperty()

{0x000007fecae18552}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-CoreUObject.dll!UObject::PostEditChange()

{0x000007fed36c6464}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-MaterialEditor.dll!FMaterialEditor::UpdatePreviewMaterial()

{0x000007fed3ce0839}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-MaterialEditor.dll!FMaterialEditor::UpdateMaterialAfterGraphChange()

{0x000007fed3cdd7d7}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-MaterialEditor.dll!FMaterialEditorUtilities::UpdateMaterialAfterGraphChange()

{0x000007fed3cdd840}

+ 9 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-UnrealEd.dll!UMaterialGraphSchema::TryCreateConnection()

{0x000007fec845a02a}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-GraphEditor.dll!FDragConnection::DroppedOnPin()

{0x000007fec7576235}

+ 28 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-GraphEditor.dll!SGraphPin::OnDrop()

{0x000007fec75f2729}

+ 123 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Slate.dll!<lambda_13af6b42409306e44b4e7065f2966a1b>::operator()()

{0x000007fecd7c39f6}

+ 176 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FPointerEvent,<lambda_13af6b42409306e44b4e7065f2966a1b> >()

{0x000007fecd77c10d}

+ 21 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent()

{0x000007fecd838641}

+ 122 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Slate.dll!FSlateApplication::OnMouseUp()

{0x000007fecd825cc4}

+ 16 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FWindowsApplication::ProcessDeferredMessage()

{0x000007fecf69b55d}

+ 12 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FWindowsApplication::DeferMessage()

{0x000007fecf682761}

+ 74 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FWindowsApplication::ProcessMessage()

{0x000007fecf69cb6f}

+ 44 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor-Core.dll!FWindowsApplication::AppWndProc()

{0x000007fecf67c34a}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
USER32.dll

{0x0000000077329bd1}

+ 0 bytes
USER32.dll

{0x00000000773298da}

+ 0 bytes
UE4Editor-Core.dll!FWindowsPlatformMisc::PumpMessages()

{0x000007fecf69df26}

+ 48 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor.exe!FEngineLoop::Tick()

{0x000000013f97486a}

+ 8 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor.exe!GuardedMain()

{0x000000013f96581c}

+ 0 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor.exe!GuardedMainWrapper()

{0x000000013f96589a}

+ 5 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor.exe!WinMain()

{0x000000013f977428}

+ 17 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\sou
UE4Editor.exe!__tmainCRTStartup()

{0x000000013f978449}

+ 21 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
kernel32.dll

{0x00000000774259ed}

+ 0 bytes
ntdll.dll

{0x000000007755c541} + 0 bytes
ntdll.dll {0x000000007755c541}

+ 0 bytes