[INFO] cloning repository https://github.com/prajwalprabhu/chatbot-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/prajwalprabhu/chatbot-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprajwalprabhu%2Fchatbot-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprajwalprabhu%2Fchatbot-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 721708c3711ddc26972ceb824ce0ca4d47eed2ef
[INFO] testing prajwalprabhu/chatbot-rs against 1.54.0 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprajwalprabhu%2Fchatbot-rs" "/workspace/builds/worker-51/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-51/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/prajwalprabhu/chatbot-rs on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/prajwalprabhu/chatbot-rs
[INFO] finished tweaking git repo https://github.com/prajwalprabhu/chatbot-rs
[INFO] tweaked toml for git repo https://github.com/prajwalprabhu/chatbot-rs written to /workspace/builds/worker-51/source/Cargo.toml
[INFO] crate git repo https://github.com/prajwalprabhu/chatbot-rs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4b644d3fe8e6c85a0145241f7122a2c34992202ee52e5699fadf387978b8ef26
[INFO] running `Command { std: "docker" "start" "-a" "4b644d3fe8e6c85a0145241f7122a2c34992202ee52e5699fadf387978b8ef26", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4b644d3fe8e6c85a0145241f7122a2c34992202ee52e5699fadf387978b8ef26", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b644d3fe8e6c85a0145241f7122a2c34992202ee52e5699fadf387978b8ef26", kill_on_drop: false }`
[INFO] [stdout] 4b644d3fe8e6c85a0145241f7122a2c34992202ee52e5699fadf387978b8ef26
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1af2b9bbfa8d2bd4e953da921208e1a5bdeaddb0e37e71da35d294b91f5f2eb6
[INFO] running `Command { std: "docker" "start" "-a" "1af2b9bbfa8d2bd4e953da921208e1a5bdeaddb0e37e71da35d294b91f5f2eb6", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling serde v1.0.125
[INFO] [stderr]    Compiling syn v1.0.69
[INFO] [stderr]    Compiling serde_derive v1.0.125
[INFO] [stderr]    Compiling serde_json v1.0.64
[INFO] [stderr]    Compiling itoa v0.4.7
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling chatbot-rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(mutex_unlock)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]    --> src/main.rs:154:5
[INFO] [stdout]     |
[INFO] [stdout] 126 | /     loop {
[INFO] [stdout] 127 | |         let result: Message = channel.recv().unwrap();
[INFO] [stdout] 128 | |         let mut members = members.lock().unwrap();
[INFO] [stdout] 129 | |         let mut stream = stream.lock().unwrap();
[INFO] [stdout] ...   |
[INFO] [stdout] 150 | |         Mutex::unlock(stream);
[INFO] [stdout] 151 | |     }
[INFO] [stdout]     | |_____- any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 154 |       Ok(())
[INFO] [stdout]     |       ^^^^^^ unreachable expression
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning 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 `chatbot-rs`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "1af2b9bbfa8d2bd4e953da921208e1a5bdeaddb0e37e71da35d294b91f5f2eb6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1af2b9bbfa8d2bd4e953da921208e1a5bdeaddb0e37e71da35d294b91f5f2eb6", kill_on_drop: false }`
[INFO] [stdout] 1af2b9bbfa8d2bd4e953da921208e1a5bdeaddb0e37e71da35d294b91f5f2eb6
