What was the rationale to recommend (and only mention) \compressMMRests instead of \compressEmptyMeasures in http://lilypond.org/doc/v2.21/Documentation/notation/writing-rests#full-measure-rests? In my opinion, it's a bit more cumbersome to use the music function syntax than the macro \compressEmptyMeasures, especially for unexperienced LilyPond users. The situation with multi-measure note durations, described in your new subsection, should be extremely rare in practice (perhaps except in cases where the user made a typo in the input). During all my years of lilypond use, I've never suffered from the problem and I've used the predecessor of \compressEmptyMeasures quite a lot.