UNION not allowed in sub-selects?

In 6.5.3, it seems that UNION is not allowed inside a sub-select:

bray=> select p.id, p.name, a.town from person* as p, address as a
bray=> where p.id in
bray-> (select id from customer union select id from supplier);
ERROR: parser: parse error at or near "union"

The same applies to EXCEPT and INTERSECT.

Is this a permanent feature, an oversight, or something already on the TODO
list?

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Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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