[INFO] cloning repository https://github.com/IkBenOlie5/math_interpreter
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/IkBenOlie5/math_interpreter" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIkBenOlie5%2Fmath_interpreter", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIkBenOlie5%2Fmath_interpreter'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 708eba6ced439175c6961aadbe582ac64b264d3c
[INFO] testing IkBenOlie5/math_interpreter against 1.59.0 for beta-1.60-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIkBenOlie5%2Fmath_interpreter" "/workspace/builds/worker-22/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-22/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/IkBenOlie5/math_interpreter on toolchain 1.59.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/IkBenOlie5/math_interpreter
[INFO] finished tweaking git repo https://github.com/IkBenOlie5/math_interpreter
[INFO] tweaked toml for git repo https://github.com/IkBenOlie5/math_interpreter written to /workspace/builds/worker-22/source/Cargo.toml
[INFO] crate git repo https://github.com/IkBenOlie5/math_interpreter already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-22/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-22/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f069ecefb066053a725ca1041ac367f2857fdd2fe214eb751e909aa5c95f6d46
[INFO] running `Command { std: "docker" "start" "-a" "f069ecefb066053a725ca1041ac367f2857fdd2fe214eb751e909aa5c95f6d46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f069ecefb066053a725ca1041ac367f2857fdd2fe214eb751e909aa5c95f6d46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f069ecefb066053a725ca1041ac367f2857fdd2fe214eb751e909aa5c95f6d46", kill_on_drop: false }`
[INFO] [stdout] f069ecefb066053a725ca1041ac367f2857fdd2fe214eb751e909aa5c95f6d46
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-22/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-22/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 37d952bd3b00f2cc5b57b2c1d2386e83cd845798b27507b8a450cebb58b74eae
[INFO] running `Command { std: "docker" "start" "-a" "37d952bd3b00f2cc5b57b2c1d2386e83cd845798b27507b8a450cebb58b74eae", kill_on_drop: false }`
[INFO] [stderr]    Compiling math_interpreter 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(let_chains)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `let_chains` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/main.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(let_chains)]
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
[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 `math_interpreter` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "37d952bd3b00f2cc5b57b2c1d2386e83cd845798b27507b8a450cebb58b74eae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "37d952bd3b00f2cc5b57b2c1d2386e83cd845798b27507b8a450cebb58b74eae", kill_on_drop: false }`
[INFO] [stdout] 37d952bd3b00f2cc5b57b2c1d2386e83cd845798b27507b8a450cebb58b74eae