[INFO] fetching crate mutagen-plugin 0.1.2...
[INFO] testing mutagen-plugin-0.1.2 against 1.55.0 for beta-1.56-1
[INFO] extracting crate mutagen-plugin 0.1.2 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate mutagen-plugin 0.1.2 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 crates.io crate mutagen-plugin 0.1.2
[INFO] finished tweaking crates.io crate mutagen-plugin 0.1.2
[INFO] tweaked toml for crates.io crate mutagen-plugin 0.1.2 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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] 73cb8d6e44dccafd904957f3fcfd73088ba29a0a721ec89fad17aef02c6af4ea
[INFO] running `Command { std: "docker" "start" "-a" "73cb8d6e44dccafd904957f3fcfd73088ba29a0a721ec89fad17aef02c6af4ea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "73cb8d6e44dccafd904957f3fcfd73088ba29a0a721ec89fad17aef02c6af4ea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "73cb8d6e44dccafd904957f3fcfd73088ba29a0a721ec89fad17aef02c6af4ea", kill_on_drop: false }`
[INFO] [stdout] 73cb8d6e44dccafd904957f3fcfd73088ba29a0a721ec89fad17aef02c6af4ea
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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] 93792c83f702b8ffc45475638429b30b1ee6bbcbcd5a3588458fd875c1238652
[INFO] running `Command { std: "docker" "start" "-a" "93792c83f702b8ffc45475638429b30b1ee6bbcbcd5a3588458fd875c1238652", kill_on_drop: false }`
[INFO] [stderr]    Compiling mutagen v0.1.2
[INFO] [stderr]    Compiling mutagen-plugin v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> build.rs:15:30
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn write_binop_arm(out: &mut Write,
[INFO] [stdout]    |                              ^^^^^ help: use `dyn`: `dyn Write`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> build.rs:59:33
[INFO] [stdout]    |
[INFO] [stdout] 59 | fn write_opassign_arm(out: &mut Write,
[INFO] [stdout]    |                                 ^^^^^ help: use `dyn`: `dyn Write`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/mutagen-0.1.2/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(specialization, atomic_min_max, try_from, assoc_unix_epoch)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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] [stderr] error: could not compile `mutagen` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "93792c83f702b8ffc45475638429b30b1ee6bbcbcd5a3588458fd875c1238652", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "93792c83f702b8ffc45475638429b30b1ee6bbcbcd5a3588458fd875c1238652", kill_on_drop: false }`
[INFO] [stdout] 93792c83f702b8ffc45475638429b30b1ee6bbcbcd5a3588458fd875c1238652