[INFO] fetching crate buffer_io 1.0.3...
[INFO] checking buffer_io-1.0.3 against beta for pr-78714
[INFO] extracting crate buffer_io 1.0.3 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate buffer_io 1.0.3 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate buffer_io 1.0.3
[INFO] finished tweaking crates.io crate buffer_io 1.0.3
[INFO] tweaked toml for crates.io crate buffer_io 1.0.3 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d77419dd5ed58f8df00e025e8a34ed00ed544c9467a3297e04d8906a4b5180d9
[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" "d77419dd5ed58f8df00e025e8a34ed00ed544c9467a3297e04d8906a4b5180d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d77419dd5ed58f8df00e025e8a34ed00ed544c9467a3297e04d8906a4b5180d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d77419dd5ed58f8df00e025e8a34ed00ed544c9467a3297e04d8906a4b5180d9", kill_on_drop: false }`
[INFO] [stdout] d77419dd5ed58f8df00e025e8a34ed00ed544c9467a3297e04d8906a4b5180d9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=forbid" "-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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", 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] 1770e0feaff0a8de8ebb31b246fe9e18b6c71dadfd6196a7b2633e65defc36c6
[INFO] running `Command { std: "docker" "start" "-a" "1770e0feaff0a8de8ebb31b246fe9e18b6c71dadfd6196a7b2633e65defc36c6", kill_on_drop: false }`
[INFO] [stderr]     Checking buffer_io v1.0.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: value assigned to `b` is never read
[INFO] [stdout]    --> src/lib.rs:211:17
[INFO] [stdout]     |
[INFO] [stdout] 211 |             let mut b: u8 = 0;
[INFO] [stdout]     |                 ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `b` is never read
[INFO] [stdout]    --> src/lib.rs:211:17
[INFO] [stdout]     |
[INFO] [stdout] 211 |             let mut b: u8 = 0;
[INFO] [stdout]     |                 ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.70s
[INFO] running `Command { std: "docker" "inspect" "1770e0feaff0a8de8ebb31b246fe9e18b6c71dadfd6196a7b2633e65defc36c6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1770e0feaff0a8de8ebb31b246fe9e18b6c71dadfd6196a7b2633e65defc36c6", kill_on_drop: false }`
[INFO] [stdout] 1770e0feaff0a8de8ebb31b246fe9e18b6c71dadfd6196a7b2633e65defc36c6