How to debug a crash?

The easiest way to (hopefully) fix this is to do a fresh (as of a few hours ago) source build of the release-1.0 branch of Julia; as advertised here that branch will likely become Julia 1.0.1, and your crash may have already been fixed there.

If that doesn’t fix it, then you really will need to debug it. There are some very helpful gdb tips in devdocs.