Heh.  I made that commit before I understood the order of TH splice processing.  `translate` is used on line 219, defined on line 297.  If the `makeLenses` call is moved next to `TransInv`, `translate` defined below the splice, so not in scope at line 219.  

I think putting the splice at the end is less fragile than moving other code around, but it's not a strong feeling.  Should I make the comment more clear, or move the rest of the `TransInv` code down below the generic transformations?