Blender 2.8 after duplicator visibility commit.
Short description of error
Crash happens in versioning code when opening file with linked particle systems.
Exact steps for others to reproduce the error
Get this two files, open scene.blend.
This is because versioning does access psys->part->foo from a do_version_280(). This do-version is called after direct linking only, meaning, pointers to library data are NOT valid. Such versioning code is to be done in do_versions_after_linking().