Freeflow assembly clang compiler error
/data/src/dumux/dumux/multidomain/subdomainstaggeredlocalassembler.hh:360:97: error: non-type template argument is not a constant expression
1885 static constexpr auto otherDomainIds = makeIncompleteIntegerSequence<Dune::Hybrid::size(jacRow), domainId>{};
1886 ^jacRow is indeed not a constexpr. The result of Dune::Hybrid::size can be actually a constexpr for special types and jacRow is I think a tuple so it works. But you are proabably not allowed to directly use it in a template because it might also be not a constexpr. Maybe we can try static constexpr auto size = Dune::Hybrid::size(jacRow); and then use size as a template argument?