There are many things about this project that a compiler can't help me with. I had to read about all of the pinouts from a PDF, draw them on a circuit board, and then map those pins in the firmware.
The code only deals with that last part, and in this particular example I decided that it was safer on the whole for the code to be obvious (easy to read + compare with hardware schematic) than to go through contortions with types to make some things more checkable by computer but less-checkable by human inspection.
The main risk here is not passing the wrong value to this match, it's fat fingering the transcription from the schematic.