Yes this is a good idea. dplyr has something similar with `mutate` & `transmute`. This could _mostly_ be enforced by PRQL. There's a case where we transpile to

Yes this is a good idea. dplyr has something similar with `mutate` & `transmute`. This could _mostly_ be enforced by PRQL. There's a case where we transpile to: select *, x+1 as x_plus_one ...where we don't know whether or not we're overwriting an existing column. But it's a minority of cases, and the contract could stand within PRQL. I opened an issue here: https://github.com/max-sixty/prql/issues/6 https://github.com/max-sixty/prql/issues/6