Re: Wrong results: NOT IN to anti-join with an upper-level Var in the sub-select's output

Hi Tender,

Thanks for looking. Moved the comment ahead of the test and left the one
inside the if alone, as you suggested; v2 attached. make check is still green
and the test still fails without the code change.

Just to be clear about what the check costs us: nothing that works today.
expr_is_nonnullable() already declines upper-level Vars, so the only way the
fallback was reaching one was by matching it against a local Var of an
unrelated relation -- there was never a correct conversion there to lose. And
proving an upper-level output non-null would take the outer query's range
table, which query_outputs_are_not_nullable() isn't given, so that would want a
different mechanism rather than a relaxation of this test.

Thanks,
Rui