failed assertion in 2.3.18

[Russ Ross]

I just compiled 2.3.18 on a Debian system and got this error:

lilypond: ../flower/include/array.hh:149: T& Array<T>::elem_ref(int)
const [with T = void*]: Assertion `i >=0&&i<size_' failed.

I got a similar error on 2.2.2 and 2.2.5 under Cygwin.  I was working
with a rather large source file, so I started removing parts and
deleting measures until I came up with the smallest example that still
crashed it; if I remove any more measures from this (beginning, end,
or middle), it compiles fine.  I haven't tried any changes other than
removing things, so an even simpler example may be possible.

The example is included below.

Thanks,

Russ



\version "2.3.18"

sopranoNotes =  \relative c'' {
  cis4 cis b2~ |
  b r |
  R1*4 |
  r2 e,2 |
  fis4 gis a gis |
}

sopranoLyrics = \lyricmode {
  schwe -- re B\"urd __
  wohl
  an dem Kreu -- ze
}

organoEContinuoBassNotes =  \relative c {
  e16( gis) gis( fis) fis( e) e( dis) dis( cis) cis( b) g'4~ |
  g16 d-. d( cis) cis( b) b( ais) ais4 r |
  r16 b'-. b( fis) fis( a) a( b,) b4 r |
  r16 e-. e( b) b( d) d( e,) e4 r |
  r16 a'-. a( gis) gis( fis) fis( eis) eis4 r |
  r16 fis,-. fis( a) a( cis) cis( e) dis8 e cis a |
  cis8 r dis r gis,16 gis'-. gis( fis) fis( e) e( b') |
  b4 r8 b, fis'4 r8 gis |
}

\score {
  \new StaffGroup \simultaneous {
    \context Staff = sopranoStaff
    \context Voice = sopranoVoice {
      \time 4/4
      \clef treble
      \key e \major
      \sopranoNotes
    }
    \lyricsto sopranoVoice \new Lyrics \sopranoLyrics
    \context Staff = organoEContinuoBassStaff  {
      \time 4/4
      \clef bass
      \key e \major
      \organoEContinuoBassNotes
    }
  }
  \paper {}
}