ALTER TABLE ... SET DATA TYPE removes statistics

The current documentation does not mention that the column statistics are removed which I can see they are in src/backend/commands/tablecmds.c

ATExecAlterColumnType
	/*
	 * Drop any pg_statistic entry for the column, since it's now wrong type
	 */
	RemoveStatistics(RelationGetRelid(rel), attnum);

Although this might be obvious it tripped me up.  For example renaming and SET STATISTICS preserves statistics.  Patch attached.

Regards,

Nikolai