When compiling with Clang 5.0.1 one gets two warnings about nested type specifiers that were probably not intended to be there in the first place. The first one is asking a *_t type trait for ::type and the second one is asking for Entity::Entity.
The exact warnings given by Clang were:
/duneci/modules/dune-subgrid/dune/subgrid/common/variant.hh:31:66: warning: ISO C++ specifies that qualified reference to 'type' is a constructor name rather than a type in this context, despite preceding 'typename' keyword [-Winjected-class-name] using Storage = typename std::aligned_storage_t<sizeof(Tp)>::type; ^
/duneci/modules/dune-subgrid/dune/subgrid/subgrid.hh:1190:67: warning: ISO C++ specifies that qualified reference to 'Entity' is a constructor name rather than a type in this context, despite preceding 'typename' keyword [-Winjected-class-name] typedef typename HostGrid::template Codim<0>::Entity::Entity HostGridElement; ^