The \hideNotes and \unHideNotes is to achieve the work-around for mixing bending strings with hammer-on and pull-offs (which are engraved using normal slurs). This is just an excerpt of what I was trying to engrave... and I think it is minimal, in the sense that if you remove any one part of it then Lilypond runs fine and produces what I expected.
Martyn
From: Federico Bruni <address@hidden>
To: Martyn Quick <address@hidden>
Cc: "address@hidden" <address@hidden>
Sent: Wednesday, 30 July 2014, 23:07
Subject: Re: Strange problem with guitar bends