Simon Praetorius authored 5 years ago and Timo Koch committed 5 years ago

Due to upstream changes in dune-common. Backward-compatible with pre dune 2.7.

Constructing a geometry to get the type is always more expensive if
you just need the type. This implement the more efficient interface.

Instead of storing a nullptr and document undefined behaviour we
can actually store a this pointer and have perfectly defined behaviour.