Slur inside tuplet bracket causing crash

[Andrew Bernard]

When I attempt to move the following slur inside the the tuplet bracket relese 
2.19.34 crashes with an assertion failure.

Excerpting the code to isolate the issue results in incorrect output and error 
messages, but no assertion failure.

What is going on here? In the context of my very large score, the assertion 
failure prevents me compiling it at all.

\version "2.19.34"

{
  \clef bass
  \time 1/4

  \stemUp
  \tupletDown
  \once \override TupletNumber.avoid-slur = #'around
  %\once \override TupletBracket.Y-offset = #2
  \tuplet 5/4 { gis,16( b,16. } 
  dis16 fis16. g32) c'^.^> r32
}

Log output:

Starting lilypond 2.19.34 [exp-crash.ly]...
Processing `/home/andro/work/lilypond/proportion/exp-crash.ly'
Parsing...
Interpreting music...
Preprocessing graphical objects...
programming error: minimise_least_squares ():  Nothing to minimise
This means that vertical spacing is triggered
before line breaking

continuing, cross fingers
Finding the ideal number of pages...
Fitting music on 1 page...
Drawing systems...
Layout output to `/tmp/lilypond-azboyo'...
Converting to `exp-crash.pdf'...
Deleting `/tmp/lilypond-azboyo'...
Success: compilation successfully completed
Completed successfully in 0.7”.

Commenting this out removes the error:

\once \override TupletNumber.avoid-slur = #’around

But this is what I need to achieve for the score.

This is the assertion faliure I get in the contrext of the larger score:

Preprocessing graphical objects...lilypond: 
/home/andro/src/lilypond-2.19.34/flower/include/interval.hh:227: T 
Interval_t<T>::center() const [with T = double]: Assertion `!is_empty ()' 
failed.
Exited with exit status 1.

Andrew