[INFO] fetching crate multitooth 0.0.1...
[INFO] testing multitooth-0.0.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate multitooth 0.0.1 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate multitooth 0.0.1 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 multitooth 0.0.1
[INFO] finished tweaking crates.io crate multitooth 0.0.1
[INFO] tweaked toml for crates.io crate multitooth 0.0.1 written to /workspace/builds/worker-10/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-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] [stdout] 5ad33923bfce0061239f958d878f784be2fbffd422332a2096152bc9a7421cb0
[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" "5ad33923bfce0061239f958d878f784be2fbffd422332a2096152bc9a7421cb0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5ad33923bfce0061239f958d878f784be2fbffd422332a2096152bc9a7421cb0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5ad33923bfce0061239f958d878f784be2fbffd422332a2096152bc9a7421cb0", kill_on_drop: false }`
[INFO] [stdout] 5ad33923bfce0061239f958d878f784be2fbffd422332a2096152bc9a7421cb0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] aeafe1d4399b4c0324618cdd0ec994befddde3626041907bd16ddb85f22913b9
[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" "aeafe1d4399b4c0324618cdd0ec994befddde3626041907bd16ddb85f22913b9", kill_on_drop: false }`
[INFO] [stderr]    Compiling multitooth v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(slicing_syntax)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(convert)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(collections)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::os`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::os;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ErrorKind`, `Error`
[INFO] [stdout]   --> src/main.rs:11:15
[INFO] [stdout]    |
[INFO] [stdout] 11 | use std::io::{Error,ErrorKind};
[INFO] [stdout]    |               ^^^^^ ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable statement
[INFO] [stdout]   --> src/main.rs:48:25
[INFO] [stdout]    |
[INFO] [stdout] 45 |                             panic!(e);
[INFO] [stdout]    |                             ---------- any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 48 |                         unsafe { ::std::mem::forget(stdout) };
[INFO] [stdout]    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unreachable statement
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `tail` found for struct `Vec<String>` in the current scope
[INFO] [stdout]   --> src/main.rs:99:41
[INFO] [stdout]    |
[INFO] [stdout] 99 |     let matches = match opts.parse(args.tail()) {
[INFO] [stdout]    |                                         ^^^^ method not found in `Vec<String>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors; 3 warnings emitted
[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 `multitooth`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "aeafe1d4399b4c0324618cdd0ec994befddde3626041907bd16ddb85f22913b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aeafe1d4399b4c0324618cdd0ec994befddde3626041907bd16ddb85f22913b9", kill_on_drop: false }`
[INFO] [stdout] aeafe1d4399b4c0324618cdd0ec994befddde3626041907bd16ddb85f22913b9