"Assertion failed!" errors

[Daniel Rosen]

Running LilyPond 2.19.21 on 64-bit Windows 7, I get an odd pop-up error dialog 
in a number of different circumstances. Below are two examples.

EXAMPLE #1 (see 
http://lists.gnu.org/archive/html/lilypond-user/2015-06/msg00278.html)

Given the following code,

\version "2.19.21"
\new Voice \with { \consists "Balloon_engraver" }
{
  \balloonGrobText #'Stem #'(3 . 3) \markup { "I'm a Stem" }
  g1
}

I get the error dialog seen in attachment "Ex1."

%%%%%%%%%%%%%

EXAMPLE #2 (see 
http://lists.gnu.org/archive/html/lilypond-user/2015-06/msg00282.html)

This code,

\version "2.19.21"
\new Staff \with { \remove "Time_signature_engraver" }
{
  \once \override TextScript.self-alignment-X = 0
  g^"TextTextTextTextText"
}

Yields attachment "Ex2."

DR

Ex1.png
Description: Ex1.png

Ex2.png
Description: Ex2.png