PVS-Studio warning V570 for UnrealEngine4

enum ECubeFace;
ECubeFace CubeFace;

friend FArchive& operator<<(
  FArchive& Ar,FResolveParams& ResolveParams)
{
  ....
  if(Ar.IsLoading())
  {
    ResolveParams.CubeFace = (ECubeFace)ResolveParams.CubeFace;
  }
  ....
}

This suspicious code was found in UnrealEngine4 project by PVS-Studio static code analyzer.
Warning message is:
V570 The 'ResolveParams.CubeFace' variable is assigned to itself. rhi.h 1279

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/