[INFO] fetching crate rust-freqdist 0.1.5...
[INFO] testing rust-freqdist-0.1.5 against 1.49.0 for beta-1.50-1
[INFO] extracting crate rust-freqdist 0.1.5 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate rust-freqdist 0.1.5 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rust-freqdist 0.1.5
[INFO] finished tweaking crates.io crate rust-freqdist 0.1.5
[INFO] tweaked toml for crates.io crate rust-freqdist 0.1.5 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 4fda722b31512c4f171a473353855051937cc8fca397def406f481621190adc9
[INFO] running `Command { std: "docker" "start" "-a" "4fda722b31512c4f171a473353855051937cc8fca397def406f481621190adc9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4fda722b31512c4f171a473353855051937cc8fca397def406f481621190adc9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4fda722b31512c4f171a473353855051937cc8fca397def406f481621190adc9", kill_on_drop: false }`
[INFO] [stdout] 4fda722b31512c4f171a473353855051937cc8fca397def406f481621190adc9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1fba4aca8a8d139f12c4c963cd5db50b6bed5cb97abc915ec3ac4b91bd233eef
[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" "1fba4aca8a8d139f12c4c963cd5db50b6bed5cb97abc915ec3ac4b91bd233eef", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-freqdist v0.1.5 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.30s
[INFO] running `Command { std: "docker" "inspect" "1fba4aca8a8d139f12c4c963cd5db50b6bed5cb97abc915ec3ac4b91bd233eef", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1fba4aca8a8d139f12c4c963cd5db50b6bed5cb97abc915ec3ac4b91bd233eef", kill_on_drop: false }`
[INFO] [stdout] 1fba4aca8a8d139f12c4c963cd5db50b6bed5cb97abc915ec3ac4b91bd233eef
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c6101bf7dc7dda1fa9a99b558f5725ad1903594611376418f93b0afca161ac1c
[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" "c6101bf7dc7dda1fa9a99b558f5725ad1903594611376418f93b0afca161ac1c", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-freqdist v0.1.5 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:29:19
[INFO] [stdout]    |
[INFO] [stdout] 29 | #![cfg_attr(test, feature(test))]
[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 `rust-freqdist`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "c6101bf7dc7dda1fa9a99b558f5725ad1903594611376418f93b0afca161ac1c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c6101bf7dc7dda1fa9a99b558f5725ad1903594611376418f93b0afca161ac1c", kill_on_drop: false }`
[INFO] [stdout] c6101bf7dc7dda1fa9a99b558f5725ad1903594611376418f93b0afca161ac1c