Comment #3 on issue 2612 by [email protected]: Patch: Issues warning for negative-spanning line spanner.
http://code.google.com/p/lilypond/issues/detail?id=2612
When we don't have room for the line, like the dashed line in "cresc.---"
{b^\cresc b b2\!}
this patch gives a warning
"Line spanner's left point is to the right of its right point"
pointing to the input (e.g., \cresc) for which LilyPond was drawing a line
spanner.
I tried it on some long scores and it was helpful, not annoying.
