1. `uncheckedCastChild` may generate redundant `CastExpr` like `cast( cast(XXX as Date) as Date)` 2. generate DateLiteral to replace cast(IntLiteral as Date)
1. `uncheckedCastChild` may generate redundant `CastExpr` like `cast( cast(XXX as Date) as Date)` 2. generate DateLiteral to replace cast(IntLiteral as Date)