bug#30874: 27.0.50; Emacs crashes

[Eli Zaretskii]

> From: Jan Synacek <jsynacek@redhat.com>
> Date: Tue, 20 Mar 2018 11:24:51 +0100
> 
> 
> Emacs crashes after executing the following on the current master
> (commit b39ca55e294d3be3e4c6e142975256d7f8cdfe76):
> 
> emacs -Q --eval="(switch-to-buffer \"*scratch*\")" --eval="(insert-char 
> #x274c)" --eval="(set-fontset-font \"fontset-default\" 'unicode \"Dejavu Sans 
> Mono\")"

Please show a C-level backtrace from the crash.

Thanks.