[INFO] fetching crate reckon 0.1.0...
[INFO] testing reckon-0.1.0 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate reckon 0.1.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate reckon 0.1.0 on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", 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-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded memchr v0.1.11
[INFO] [stderr]   Downloaded thread-id v2.0.0
[INFO] [stderr]   Downloaded thread_local v0.2.7
[INFO] [stderr]   Downloaded regex-syntax v0.3.9
[INFO] [stderr]   Downloaded utf8-ranges v0.1.3
[INFO] [stderr]   Downloaded regex v0.1.80
[INFO] [stderr]   Downloaded aho-corasick v0.5.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5bc5593b4267cb22e5e64bdbaa2a1649c5b7ccc70e79d197e7939b7211634e17
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "5bc5593b4267cb22e5e64bdbaa2a1649c5b7ccc70e79d197e7939b7211634e17", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5bc5593b4267cb22e5e64bdbaa2a1649c5b7ccc70e79d197e7939b7211634e17", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5bc5593b4267cb22e5e64bdbaa2a1649c5b7ccc70e79d197e7939b7211634e17", kill_on_drop: false }`
[INFO] [stdout] 5bc5593b4267cb22e5e64bdbaa2a1649c5b7ccc70e79d197e7939b7211634e17
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 49c0129190c6ea2bd468f4be006ac0b4c289b499267d25d4a25dedbfb3bb7412
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "49c0129190c6ea2bd468f4be006ac0b4c289b499267d25d4a25dedbfb3bb7412", kill_on_drop: false }`
[INFO] [stderr]    Compiling reckon v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta 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`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "49c0129190c6ea2bd468f4be006ac0b4c289b499267d25d4a25dedbfb3bb7412", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "49c0129190c6ea2bd468f4be006ac0b4c289b499267d25d4a25dedbfb3bb7412", kill_on_drop: false }`
[INFO] [stdout] 49c0129190c6ea2bd468f4be006ac0b4c289b499267d25d4a25dedbfb3bb7412