Re: Proving IS NOT NULL inference for ScalarArrayOpExpr's

Hello, I gave this patch a very quick scan.  I didn't check the actual
logic behind it.

This comment seems wrong:

+ * However weak implication fails: e.g., "NULL IS NOT NULL" is false, but
+ * "NULL = ANY(ARRAY[NULL])" is NULL, so non-falsity does not imply non-falsity.

"non-falsity does not imply non-falsity"?  I suppose one of those
negations should be different ...

I think the name clause_proved_for_null_test() is a bit weird, being in
the past tense.  I'd maybe change "proved" to "proves".

s/exppresions/expresions/ in the test files.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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