The whole point of introducing LOCK_temporary_tables was to protect reads in fill_global_temporary_tables() from concurrent thd->temporary_tables modifications in other threads.
Since fill_temporary_tables() is only used to read the current connection's list of temporary tables, no concurrent modifications are possible. Thus the bug is invalid.
The whole point of introducing LOCK_temporary_ tables was to protect reads in fill_global_ temporary_ tables( ) from concurrent thd->temporary_ tables modifications in other threads.
Since fill_temporary_ tables( ) is only used to read the current connection's list of temporary tables, no concurrent modifications are possible. Thus the bug is invalid.