This seems to only come up for VS2019 Intellisense:
Error (active) E0434 a reference of type "FMeshDrawSingleShaderBindings &" (not const-qualified) cannot be initialized with a value of type "FMeshDrawSingleShaderBindings" UE4 C:\Program Files\Epic Games\UE_4.22\Engine\Source\Runtime\RenderCore\Public\VertexFactory.h 634