Option to allow the system to automatically set the datatype for a line item

It would be really helpful to me when building complex formulas if I could build it up in pieces without creating lots of line items to do so. Ideally I could build it in pieces without getting plagued with "wrong data type" errors.

I'd like the option to let the system adjust the datatype for me instead of just rejecting my formula for a datatype issue.  This would allow me to more easily try a small piece of a formula to see if what I get is as expected, then add to it to see again (likely a new datatype) without me having to change the datatype myself.