[INFO] cloning repository https://github.com/busarovalex/mp3-meta
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/busarovalex/mp3-meta" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbusarovalex%2Fmp3-meta", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbusarovalex%2Fmp3-meta'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] dc2f9188c6fba277153926f265aebfd61e5a7f37
[INFO] testing busarovalex/mp3-meta against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbusarovalex%2Fmp3-meta" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/busarovalex/mp3-meta on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/busarovalex/mp3-meta
[INFO] finished tweaking git repo https://github.com/busarovalex/mp3-meta
[INFO] tweaked toml for git repo https://github.com/busarovalex/mp3-meta written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/busarovalex/mp3-meta already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded textwrap v0.8.0
[INFO] [stderr]   Downloaded derive_builder v0.4.7
[INFO] [stderr]   Downloaded cc v1.0.1
[INFO] [stderr]   Downloaded derive_builder_core v0.1.7
[INFO] [stderr]   Downloaded clap v2.26.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e065e62bee726bbe730e3eaf4e515efa8a790c4aeea1aa1e960884397e158393
[INFO] running `Command { std: "docker" "start" "-a" "e065e62bee726bbe730e3eaf4e515efa8a790c4aeea1aa1e960884397e158393", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e065e62bee726bbe730e3eaf4e515efa8a790c4aeea1aa1e960884397e158393", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e065e62bee726bbe730e3eaf4e515efa8a790c4aeea1aa1e960884397e158393", kill_on_drop: false }`
[INFO] [stdout] e065e62bee726bbe730e3eaf4e515efa8a790c4aeea1aa1e960884397e158393
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 72dac0f09f5630a3aba5d23ef3615897bdabc2f5978b2a65c18c7571b756602e
[INFO] running `Command { std: "docker" "start" "-a" "72dac0f09f5630a3aba5d23ef3615897bdabc2f5978b2a65c18c7571b756602e", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.31
[INFO] [stderr]    Compiling cc v1.0.1
[INFO] [stderr]    Compiling derive_builder v0.4.7
[INFO] [stderr]    Compiling syn v0.11.11
[INFO] [stderr]    Compiling memchr v1.0.1
[INFO] [stderr]    Compiling term_size v0.3.0
[INFO] [stderr]    Compiling atty v0.2.2
[INFO] [stderr]    Compiling textwrap v0.8.0
[INFO] [stderr]    Compiling aho-corasick v0.6.3
[INFO] [stderr]    Compiling miniz-sys v0.1.10
[INFO] [stderr]    Compiling clap v2.26.2
[INFO] [stderr]    Compiling regex v0.2.2
[INFO] [stderr]    Compiling derive_builder_core v0.1.7
[INFO] [stderr]    Compiling flate2 v0.2.20
[INFO] [stderr]    Compiling id3 v0.2.1 (https://github.com/jameshurst/rust-id3.git?rev=21ebef8706dd5f2b1bf6b05cc87ded3b20d54dcd#21ebef87)
[INFO] [stderr]    Compiling mp3meta 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(iterator_for_each)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `mp3meta` due to 2 previous errors
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "72dac0f09f5630a3aba5d23ef3615897bdabc2f5978b2a65c18c7571b756602e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "72dac0f09f5630a3aba5d23ef3615897bdabc2f5978b2a65c18c7571b756602e", kill_on_drop: false }`
[INFO] [stdout] 72dac0f09f5630a3aba5d23ef3615897bdabc2f5978b2a65c18c7571b756602e