find-definition does not work in *read-only* projects like rust-source

[colin-kiegel]

find-definiton works fine in my projects even on std-library use std::collections::HashMap; - it jumps directly into my rust-source at /usr/local/src/rust/src/. However this is readonly - and I would like to keep it that way.

If I want to explore rust-source by use of find-definition it does not work unless I make it writable for my current user.

I understand that racer needs to have some temporary files. But shouldn't it be possible to explore read-only repositories? I think racer could use a standard-temporary directory like /var or /tmp in that case (or even in general).

What do you think?