ALTER INDEX not working in 9.5.1?

The commands "ALTER INDEX ... RENAME TO..." and "ALTER INDEX ... SET
TABLESPACE ..." seem to work as expected in PostgreSQL 9.4.5 but in 9.5.1
they fail with "ERROR: <index_name> is an index".

I can't find anything in the docs which would explain this.

Sample code:

CREATE TABLE test AS SELECT 1 AS x; --Works fine
CREATE INDEX test_idx ON test(x); --Works fine
ALTER INDEX test_idx RENAME TO other_idx; --Works fine in 9.4.5, throws
"is an index" error in 9.5.1
ALTER INDEX test_idx SET TABLESPACE other_tablespace; --Works fine in
9.4.5, throws "is an index" error in 9.5.1