The most recent changes to builtin.c result in a double free in running the test suite. I have more details if you need them. - Vin zsh remote: Counting objects: 9, done. remote: Compressing objects: 100% (5/5), done. remote: Total 5 (delta 4), reused 0 (delta 0) Unpacking objects: 100% (5/5), done. >From git://zsh.git.sf.net/gitroot/zsh/zsh 5b00bfe..1e6fb1a master -> origin/master Updating 5b00bfe..1e6fb1a Fast-forward ChangeLog | 4 ++++ Src/builtin.c | 7 ++++--- 2 files changed, 8 insertions(+), 3 deletions(-) Building zsh /opt/src/zsh-2015-05-04 cd . && ./.preconfig Configuring zsh-2015-05-04 for installation prefix /opt/zsh-2015-05-04. Building zsh...done. Running tests...% print ten ten nine one print print print one two three four five six seven eight nine ten one two print mystery sequence print one print two print mystery sequence print metaphor\? shmetaphor! print metaphor! print -l metophor, Molochi, echo $(echo foo bar) again echo more $( echo $(echo foo bar) again ) done. *** Error in `zsh': double free or corruption (out): 0x00007fff694af880 ***