Problem with dynamic linking crate 'rand'

[mverleg]

When I run this:

runner --add rand
echo "use rand;" > mwe.rs
runner mwe.rs

I get this error:

error: extern location for rand does not exist: /home/mark/.cargo/.runner/unstable/dy-cache/librand.so
error[E0463]: can't find crate for `rand`
  --> /home/user/.cargo/.runner/unstable/bin/mwe.rs:20:5
   |
20 | use rand;
   |     ^^^^ can't find crate

I think the first line means there's something going wrong with linking. I tried with -s:

runner -s mwe.rs

and indeed that works fine. I don't know how to solve it though.

P.s.: I like the tool, cool idea!

[stevedonovan]

Dynamic linking comes with some serious limitations. First, you actually have to do runner -C rand. This fails because rand has dependencies, and some of them simply can't be dynamically linked. For straightforward stuff like json crate, runner -C json does the job, but in general -s will be needed.

Dynamic linking is somewhat faster but the static case isn't too bad...

Oh yes, I do a lot of prototyping - if I'm curious about an API, I open up a little file or just do -e