Blender Version
Broken:
2.80, fa1d5586a1ad, 2019-01-25

Short description of error
editmesh_undo.c can't revert name changes on active object

Exact steps for others to reproduce the error
Open default startup .blend
With "Cube" selected, switch to edit mode
Change name of "Cube" in Outliner or Object Properties
Ctrl-Z will cause the crash.

Same crash as T60849

Crash happens in static void mesh_undosys_step_decode(struct bContext *C, UndoStep *us_p, int UNUSED(dir)) with us_p->name as "Toggle Editmode" if the name was changed in Object Properties or "Outliner selection change" for a change in Outliner.