I think complete support for F2008 and F2018 in nvfortran is deferred until new-flang (llvm flang) is ready for prime time. At the rate (or lack of) that new FLANG is progressing, I doubt it will be anytime soon. It’s disappointing (at least to me) that I can’t do a sudo apt install llvm-flang etc and get a working (as in generate an executable binary) compiler