It's been several times I encounter this crash.
First I type 'll' but instead of validating with <Enter>, I type '\' by mistake (cause the touch is just above). Then I type <Enter>. Zsh thinks it's a multiline command, so it displays the '>' prompt. Here, I notice my mistake so I interrupt the command with <C-c>. Finally I properly type 'll' followed by <Enter> and it crashes...
Here is a log:
prompt % ll\
> (<- here you must enter C-c)
prompt % ll
Warning: Program '/bin/zsh' crashed.
Info: my term emulator is Konsole, on ArchLinux.