So gentlemen, since this is a regular source of confusion, and it certainly has had me glued up for many days wondering what is wrong with my code, should this not be raised as a defect, or at the very least the adjetctive ‘fatal’ removed fromt he message, and replaced with ‘warning’ or something else?
As to lilypond making a best effort at producing output, I have never seen this referred to in the NR. That ought to go in somewhere. But for my preference, a serious syntax error which is just outright garbage should in my opinion not produce any output. Other types of compilers would stop. If there is such an error it neeeds attention, not PDF output I reckon. I think this is best moved to the bug list for discussion. I think aberrant behaviour that does not match ordinary expectations can fairly be classed as a bug.
Andrew