[INFO] fetching crate esl 0.8.0...
[INFO] testing esl-0.8.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate esl 0.8.0 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate esl 0.8.0 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 esl 0.8.0
[INFO] finished tweaking crates.io crate esl 0.8.0
[INFO] tweaked toml for crates.io crate esl 0.8.0 written to /workspace/builds/worker-13/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-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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] 44aa8d14a13c51167db401764d25da8eaea63753f44a2d9b341eeafb54d3672d
[INFO] running `Command { std: "docker" "start" "-a" "44aa8d14a13c51167db401764d25da8eaea63753f44a2d9b341eeafb54d3672d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "44aa8d14a13c51167db401764d25da8eaea63753f44a2d9b341eeafb54d3672d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "44aa8d14a13c51167db401764d25da8eaea63753f44a2d9b341eeafb54d3672d", kill_on_drop: false }`
[INFO] [stdout] 44aa8d14a13c51167db401764d25da8eaea63753f44a2d9b341eeafb54d3672d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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] 1c89326eda4dbb41feea2de0fe8acab06c599295c2cf26a0150ae261f9cdcea1
[INFO] running `Command { std: "docker" "start" "-a" "1c89326eda4dbb41feea2de0fe8acab06c599295c2cf26a0150ae261f9cdcea1", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling encoding_index_tests v0.1.4
[INFO] [stderr]    Compiling crc32fast v1.2.1
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling lexical-core v0.7.6
[INFO] [stderr]    Compiling arrayvec v0.5.2
[INFO] [stderr]    Compiling static_assertions v1.1.0
[INFO] [stderr]    Compiling bitflags v1.3.2
[INFO] [stderr]    Compiling macro-attr-2018 v1.1.1
[INFO] [stderr]    Compiling nameof v1.2.1
[INFO] [stderr]    Compiling enum-derive-2018 v1.0.2
[INFO] [stderr]    Compiling base64 v0.12.3
[INFO] [stderr]    Compiling once_cell v1.8.0
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-bigint v0.4.2
[INFO] [stderr]    Compiling nom v5.1.2
[INFO] [stderr]    Compiling encoding-index-singlebyte v1.20141219.5
[INFO] [stderr]    Compiling encoding-index-tradchinese v1.20141219.5
[INFO] [stderr]    Compiling encoding-index-korean v1.20141219.5
[INFO] [stderr]    Compiling encoding-index-simpchinese v1.20141219.5
[INFO] [stderr]    Compiling encoding-index-japanese v1.20141219.5
[INFO] [stderr]    Compiling encoding v0.2.33
[INFO] [stderr]    Compiling flate2 v1.0.21
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]    Compiling enum-ordinalize v3.1.10
[INFO] [stderr]    Compiling enumn v0.1.3
[INFO] [stderr]    Compiling educe v0.4.18
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling either v1.6.1
[INFO] [stderr]    Compiling esl v0.8.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(type_alias_impl_trait)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(stmt_expr_attributes)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(macro_attributes_in_derive_output)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `esl` due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "1c89326eda4dbb41feea2de0fe8acab06c599295c2cf26a0150ae261f9cdcea1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1c89326eda4dbb41feea2de0fe8acab06c599295c2cf26a0150ae261f9cdcea1", kill_on_drop: false }`
[INFO] [stdout] 1c89326eda4dbb41feea2de0fe8acab06c599295c2cf26a0150ae261f9cdcea1