There ARE missing includes on nvidias 4.19 FleX that might trigger errors if you actually change the file (add or change actual code in it), but simply opening it wouldn’t do . What you said about manually fixing the issues by adding includes would just confirm . I’ve made PR for 4.19 FleX but Nvidia hasn’t accepted it: /pull/523. fixes at least some of the missing includes required to actually package FleX.