Rust 1.22.0 prerelease testing!

No, unfortunately doesn’t:

% cargo clean
% cargo build
   Compiling core-foundation-sys v0.2.3
   ...
   Compiling qringtool v0.2.1 (file:///private/tmp/2GinlUpbELdBN/qringtool)
error: failed to link or copy `/private/tmp/2GinlUpbELdBN/qringtool/target/debug/deps/qringtool-219c27fe46a7576a.dSYM` to `/private/tmp/2GinlUpbELdBN/qringtool/target/debug/qringtool.dSYM`

Caused by:
  the source path is not an existing regular file
% cargo --version
cargo 0.23.0 (cee38cd30 2017-11-12)

but it does on nightly:

% cargo +nightly clean
% cargo +nightly build
   ...
   Compiling qringtool v0.2.1 (file:///private/tmp/2GinlUpbELdBN/qringtool)
    Finished dev [unoptimized + debuginfo] target(s) in 85.94 secs
% cargo +nightly --version
cargo 0.24.0-nightly (abd137ad1 2017-11-12)