How to debug `"....")`?

I have some trouble building a package ArbNumberics.jl. (See here.)

So I tried to use Debugger.jl to debug it by

Using Debugger, Pkg
1|debug> bp on error
1|debug> c

But this seems to take forever to run. If I switch to compelled mode, then code does run but it does not break on error.

Is there actually a way to debug it?