opt: ensure NULLs folded out of a CASE are typed #35188
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Fixes cockroachdb#34930. Previously, we could have two well-typed CASE statements that had a valid binary overload and thus would pass semantic analysis. However, via SimplifyCaseWhenConstValue, we could fold away the CASEs, leaving us with only two untyped NULLs (which will not have a valid overload). The "right" thing to do might be to change the type-checker to have the NULLs come in through the AST as typed, but this is a bigger change since the current AST has no notion of a typed null (there's only a singleton NULL). Release note (bug fix): fix a panic that could occur via certain patterns of folding CASE statements containing NULLs.
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maddyblue
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Feb 25, 2019
RaduBerinde
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complete! 1 of 0 LGTMs obtained (waiting on @rytaft)
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35188: opt: ensure NULLs folded out of a CASE are typed r=justinj a=justinj Fixes #34930. Previously, we could have two well-typed CASE statements that had a valid binary overload and thus would pass semantic analysis. However, via SimplifyCaseWhenConstValue, we could fold away the CASEs, leaving us with only two untyped NULLs (which will not have a valid overload). The "right" thing to do might be to change the type-checker to have the NULLs come in through the AST as typed, but this is a bigger change since the current AST has no notion of a typed null (there's only a singleton NULL). Release note (bug fix): fix a panic that could occur via certain patterns of folding CASE statements containing NULLs. cc @mjibson Co-authored-by: Justin Jaffray <justin@cockroachlabs.com>
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Fixes #34930.
Previously, we could have two well-typed CASE statements that had a
valid binary overload and thus would pass semantic analysis. However,
via SimplifyCaseWhenConstValue, we could fold away the CASEs, leaving us
with only two untyped NULLs (which will not have a valid overload).
The "right" thing to do might be to change the type-checker to have the
NULLs come in through the AST as typed, but this is a bigger change
since the current AST has no notion of a typed null (there's only a
singleton NULL).
Release note (bug fix): fix a panic that could occur via certain
patterns of folding CASE statements containing NULLs.
cc @mjibson