The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/11/queries-table-expressions.html
Description:
in the above example it seems as though the result
CUBE(a,(b,c),d)
GROUPING SETS (
( a, b, c, d ),
( a, b, c ),
( a ),
( )
)
should include ( b, c, d )