Trillspan not showing accidental & a problem with its ending

[Hans Aberg]

Two problems with the \pitchedTrill construct:

First, the accidental of the auxiliary is not shown in this  
particular code:

\version "2.11.35"
above = { \once \override Script #'script-priority = #-100 }

\relative c' {
  \key d \minor
  \time 12/16
  \set beatGrouping = #'(3 2 2 3 2)
  \set subdivideBeams = ##t
  #(override-auto-beam-setting '(end * * 12 16) 3 16)
  #(override-auto-beam-setting '(end * * 12 16) 7 16)
  #(override-auto-beam-setting '(end * * 12 16) 10 16)

  \times 3/4 {g'8 f8~} f4 ~ \pitchedTrill f8.~\startTrillSpan ges f8~ |
  \above f8.\prall^\markup{\flat} \stopTrillSpan ~f4 r8. r8 |
}

The output looks as in the first attached image below. Now, if I  
replace the first quadruplet with a rest (r8.), then the auxiliary  
accidental is shown. It looks as in the second image below. So, in  
fact, this is a minimal example for this bug. It odes not seem to  
matter what is put in the first quadruplet, though - only that it is  
there.

The second problem is that the trill spanner extends into the  
following note, in this case the first note of the second measure.  
The musical intent here is that the trill should be continued through  
last 1/8 note of the first measure, but the first note of the second  
measure should only have a pralltriller. If, in the code, I move  
forward the \stopTrillSpan to after the last note of the first  
measure, then it looks as though it should not be trilled. So here,  
there might be needed some rendering refinement, so that the trill  
spanner stops shortly shortly after the last note in the trill. Then  
there should be plenty of room for both the \prall and its accidental  
in the code.

  Hans Åberg