Worked on the TobikoData/sqlmesh repository to address a nuanced issue in SQL expression rewriting, focusing on preserving subclass casting semantics such as those for JSONCast. Using Python and SQL, implemented a targeted bug fix that prevents the rewriting of casts for specific subclasses, ensuring that intended data type handling remains intact during query generation. This approach reduced the risk of incorrect query results and improved the stability of the rewrite path for complex casts. Enhanced test coverage around edge cases in cast rewriting, validating that subclass-specific semantics are maintained. Emphasized careful testing and robust handling of SQL casting logic throughout.