[INFO] cloning repository https://github.com/dark64/opt-playground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/dark64/opt-playground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdark64%2Fopt-playground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdark64%2Fopt-playground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 2f7e2f4b175e0777319e3333b7c9fd1e56b52566
[INFO] testing dark64/opt-playground against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdark64%2Fopt-playground" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/dark64/opt-playground on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/dark64/opt-playground
[INFO] finished tweaking git repo https://github.com/dark64/opt-playground
[INFO] tweaked toml for git repo https://github.com/dark64/opt-playground written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/dark64/opt-playground already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 2c0963281d4b98b20c4f83b89073fb4a273fd88b8929b015f76483d59f468362
[INFO] running `Command { std: "docker" "start" "-a" "2c0963281d4b98b20c4f83b89073fb4a273fd88b8929b015f76483d59f468362", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2c0963281d4b98b20c4f83b89073fb4a273fd88b8929b015f76483d59f468362", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2c0963281d4b98b20c4f83b89073fb4a273fd88b8929b015f76483d59f468362", kill_on_drop: false }`
[INFO] [stdout] 2c0963281d4b98b20c4f83b89073fb4a273fd88b8929b015f76483d59f468362
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f69fc6e64762090e072333648e4f7161d5d10e42ff251d8dffc38295ecf08e1e
[INFO] running `Command { std: "docker" "start" "-a" "f69fc6e64762090e072333648e4f7161d5d10e42ff251d8dffc38295ecf08e1e", kill_on_drop: false }`
[INFO] [stderr]    Compiling opt-playground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `arguments`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     pub arguments: Vec<T>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] note: `Prog` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   --> src/main.rs:8:10
[INFO] [stdout]    |
[INFO] [stdout] 8  | #[derive(Debug)]
[INFO] [stdout]    |          ^^^^^
[INFO] [stdout]    = note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `statements`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     pub statements: Vec<T>
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] note: `Prog` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   --> src/main.rs:8:10
[INFO] [stdout]    |
[INFO] [stdout] 8  | #[derive(Debug)]
[INFO] [stdout]    |          ^^^^^
[INFO] [stdout]    = note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(test)]
[INFO] [stdout]   |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `opt-playground` due to 2 previous errors; 2 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "f69fc6e64762090e072333648e4f7161d5d10e42ff251d8dffc38295ecf08e1e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f69fc6e64762090e072333648e4f7161d5d10e42ff251d8dffc38295ecf08e1e", kill_on_drop: false }`
[INFO] [stdout] f69fc6e64762090e072333648e4f7161d5d10e42ff251d8dffc38295ecf08e1e