Compilation fails with: feature edition is required

[triska]

With the latest commit, when I do:

$ cargo install scryer-prolog

I get:

    Updating registry `https://github.com/rust-lang/crates.io-index`
  Installing scryer-prolog v0.8.89
error: failed to compile `scryer-prolog v0.8.89`, intermediate artifacts can be found at `/tmp/cargo-installqEB7Fd`

Caused by:
  unable to get packages from source

Caused by:
  failed to parse manifest at `~/.cargo/registry/src/github.com-1ecc6299db9ec823/rug-1.6.0/Cargo.toml`

Caused by:
  editions are unstable

Caused by:
  feature `edition` is required

consider adding `cargo-features = ["edition"]` to the manifest

Per rust-lang/cargo#6113, I tried:

 $ cargo install --force cargo-outdated

Which yields:

    Updating registry `https://github.com/rust-lang/crates.io-index`
error: failed to parse manifest at `/home/mt/.cargo/registry/src/github.com-1ecc6299db9ec823/cargo-outdated-0.8.0/Cargo.toml`

Caused by:
  editions are unstable

Caused by:
  feature `edition` is required

consider adding `cargo-features = ["edition"]` to the manifest

[triska]

$ cargo --version
cargo 1.28.0

Tried on a 2018 version of Ubuntu.

[mthom]

Does adding cargo-features = ["edition"] to Cargo.toml help?

[triska]

I have added this line to every section of Cargo.toml, and still get exactly the same error message.

[mthom]

I'll try it on my Ubuntu when I get home.

[XVilka]

@triska it's a problem of Ubuntu/Debian distributions. They are always too slow to update. Just use rustup, it works fine with all channels - see stable, beta, and nightly channels: #159

[triska]

@XVilka: Thank you for looking into this. Could you please suggest a patch for the README that lets us more reliably build Scryer Prolog? For example, how do I best "use rustup"?

[triska]

I have now successfully compiled Scryer Prolog with cargo 1.34, which ships with the newly released Debian buster (Debian 10), so I am closing this issue. Thank you for looking into it!