Fw: [testlilyissues:issues] Moderation action required

[Trevor]

Forwarding on behalf of Jean Abou Samra as I deleted the message in 
SourceForge by mistake :( I don't know what the original subject line 
was, and the attachment is lost. Sorry! Perhaps Jean could resubmit.

Trevor

------ Forwarded Message ------
From: "Jean Abou Samra" <address@hidden>
To: address@hidden
Sent: 14/07/2019 20:23:46
Subject: [testlilyissues:issues] Moderation action required

The following submission requires approval at 
https://sourceforge.net/p/testlilyissues/issues/_discuss/moderate before it can 
be approved for posting:'t

Also reported on Mac OS (at least 10.12.6 Sierra [me] and 10.13.6 High Sierra 
[Michael Hendry]) with LilyPond 2.21.0, but _not_  LilyPond 2.19.83, quite 
surprisingly as the bug appeared with 2.19.19 on Windows. Both above examples 
are reproduced, and I can add a third one:
```
\version "2.21.0"
\relative {
c'1
\acciaccatura { bes8 } c1
}
```
Full outputs and logs on the three examples using 2.21.0, 2.19.83 and 2.18.2 
are available in the attached archive.
Two additional remarks:
* On the first example, "mis-predicted force" programming errors show up, and 
yet the output is perfectly normal, the staff doesn't protrude.
* On the last example, the bug is triggered as soon as the grace note is 
altered, no matter the alteration and no matter wether \acciaccatura or \grace 
is used.
Hope that helps!