I vaguely remember someone telling me, a long time ago, that Thomas Reps' PhD thesis

(https://ieeexplore.ieee.org/book/6267325)

showed that it wasn't practical to build this kind of editor. Perhaps that was not at all the point; it was a long time ago.

I wonder, though, can anyone explain 1) if Reps' thesis does bear on the Treefrog work 2) what it was in Reps' thesis that bears on the difficulty of making syntax-tree based code development tools?