let (basename, suffix) = splitFilename input_fn
-- If we were given a -x flag, then use that phase to start from
- start_phase
- | Just x_phase <- mb_phase = x_phase
- | otherwise = startPhase suffix
+ start_phase = fromMaybe (startPhase suffix) mb_phase
-- We want to catch cases of "you can't get there from here" before
-- we start the pipeline, because otherwise it will just run off the