If .. is a spread operator, then you can’t use raw # in code mode, it just won’t compile.
The example indeed does not compile, for the above reason, and because the column number is not known. Default in 1 and x: 6 is invalid for it. You also don’t show how data is defined. It just so happen that I recognize this data structure from How do i make a cell's colspan depend on the column title (in my data)?. Otherwise, we can only pretend that it’s #let data = (carrierInfo: (tableInfo: range(5))), which will still fail for the last complex function chaining.