Can redo with interface_view.cc. Can’t redo with node_geo_curve_sample.cc
(Blender fails to compile macOS (clang seg fault)) though.
Checking.
EDIT
source/blender/editors/interface/interface_view.cc:48
using TreeViewPtr = std::unique_ptr<AbstractTreeView>;
...
std::variant<TreeViewPtr> view;
is causing this.