Alex Behm has posted comments on this change.

Change subject: IMPALA-1286: Extract common conjuncts from disjunctions.
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Patch Set 5:

I don't agree with the argument that the new behavior with constant folding 
will be less intuitive. I think it will be more user friendly.

In your example, of CTAS I think a reasonable user can expect:

insert into t select 1 + 1

to work if t has a tinyint column.

I think the only way we can satisfy your design goal is to always defer to the 
widest type, i.e. 1 + 1 -> smallint.

For simple cases we can fold in place, but with more complicated examples we 
have to substitute against inline view expressions to even realize something is 
constant, so that doesn't seem feasible to me.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I3cf9b950afaa3fd753d1b09ba5e540b5258940ad
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Alex Behm <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Bharath Vissapragada <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
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