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Changelog category (leave one):

• Bug Fix

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Fixed Element ... is not a constant expression error when using JSON* function result in VALUES, LIMIT or right side of IN operator.

Detailed description / Documentation draft:
JSON* functions return non-constant result for constant arguments:

select JSONExtract('{"a":[1, 2]}', 'a', 'Array(UInt32)') as a,  1 in a

Code: 36, e.displayText() = DB::Exception: Element of set in IN, VALUES or LIMIT is not a constant expression (result column is not const): JSONExtract('{a:[1, 2]}', 'a', 'Array(UInt32)') (version 20.9.1.4543 (official build))

Seems like these functions should work fine with default implementation for constant columns.