Note: Probably affects other versions, but I haven't tested them.

Running {{/locate }}in a world without structure generation enabled stops entities from moving, spawning, or despawning; prevents item deletion in the creative inventory; and prevents commands from being run.

Normally, this occurs for just a few seconds after running /locate before the requested structure is found; on these types of worlds, structures can never be found, so the game continues looking until the it's forced to close (logging out keeps the game on the "Saving world..." screen until force closed).

The game output log is attached. The exact command I ran was /locate Nether_Fossil and it was run within the Nether on a superflat world without generated structures. At the end, I forced the game to crash with F3+C.