I was trying to update my project to UE5.21, but one of my modules failed to compile with error : Severity Code Description Project File Line Suppression State
Error C3646 ‘Platform’: unknown override specifier MigJourney C:\Program Files\Epic Games\UE_5.2\Engine\Source\Runtime\RHI\Public\DataDrivenShaderPlatformInfo.h 156
to put you in context, the said module uses slats, for a async loading screen.
it seems that slats and RHIDefinitions conflict.
if you face the same error just add include “RHIDefinitions.h” before any slate related header and you should be good to go.
I hope though this will be automatically prevented in future releases, as it is very frustrating and basically no documentations available to help in the debugging process.