[INFO] fetching crate reckon 0.1.0...
[INFO] testing reckon-0.1.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate reckon 0.1.0 into /workspace/builds/worker-79/source
[INFO] validating manifest of crates.io crate reckon 0.1.0 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 reckon 0.1.0
[INFO] finished tweaking crates.io crate reckon 0.1.0
[INFO] tweaked toml for crates.io crate reckon 0.1.0 written to /workspace/builds/worker-79/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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] 35bf567297306dbdce4f025e3d76281d830862f4cb5306977e64bc758050613a
[INFO] running `Command { std: "docker" "start" "-a" "35bf567297306dbdce4f025e3d76281d830862f4cb5306977e64bc758050613a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "35bf567297306dbdce4f025e3d76281d830862f4cb5306977e64bc758050613a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "35bf567297306dbdce4f025e3d76281d830862f4cb5306977e64bc758050613a", kill_on_drop: false }`
[INFO] [stdout] 35bf567297306dbdce4f025e3d76281d830862f4cb5306977e64bc758050613a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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] 47920dc2dd797d837f33e2bf4177c469b6824c6bbfe9917c3b98577c3b6b7ae5
[INFO] running `Command { std: "docker" "start" "-a" "47920dc2dd797d837f33e2bf4177c469b6824c6bbfe9917c3b98577c3b6b7ae5", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]    Compiling winapi v0.2.8
[INFO] [stderr]    Compiling utf8-ranges v0.1.3
[INFO] [stderr]    Compiling regex-syntax v0.3.9
[INFO] [stderr]    Compiling memchr v0.1.11
[INFO] [stderr]    Compiling aho-corasick v0.5.3
[INFO] [stderr]    Compiling kernel32-sys v0.2.2
[INFO] [stderr]    Compiling thread-id v2.0.0
[INFO] [stderr]    Compiling thread_local v0.2.7
[INFO] [stderr]    Compiling regex v0.1.80
[INFO] [stderr]    Compiling reckon v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![feature(io)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `chars` found for mutable reference `&mut ChildStdout` in the current scope
[INFO] [stdout]    --> src/base.rs:154:28
[INFO] [stdout]     |
[INFO] [stdout] 154 |         let mut c = stdout.chars();
[INFO] [stdout]     |                            ^^^^^ method not found in `&mut ChildStdout`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `reckon` due to 3 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "47920dc2dd797d837f33e2bf4177c469b6824c6bbfe9917c3b98577c3b6b7ae5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "47920dc2dd797d837f33e2bf4177c469b6824c6bbfe9917c3b98577c3b6b7ae5", kill_on_drop: false }`
[INFO] [stdout] 47920dc2dd797d837f33e2bf4177c469b6824c6bbfe9917c3b98577c3b6b7ae5