[INFO] cloning repository https://github.com/luxn/flut
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/luxn/flut" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluxn%2Fflut", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluxn%2Fflut'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 294d41a24ebe241bb75413f01d8c939f87aff1e0
[INFO] checking luxn/flut against master#6526e5c772f2da07db745c94ca6bb0a591a39ba4 for pr-80920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluxn%2Fflut" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/luxn/flut on toolchain 6526e5c772f2da07db745c94ca6bb0a591a39ba4
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/luxn/flut
[INFO] finished tweaking git repo https://github.com/luxn/flut
[INFO] tweaked toml for git repo https://github.com/luxn/flut written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/luxn/flut already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ec85dc568359cf71967c12d34f7231740065991ae9cbd19ee542d6cb3bebf686
[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" "ec85dc568359cf71967c12d34f7231740065991ae9cbd19ee542d6cb3bebf686", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ec85dc568359cf71967c12d34f7231740065991ae9cbd19ee542d6cb3bebf686", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ec85dc568359cf71967c12d34f7231740065991ae9cbd19ee542d6cb3bebf686", kill_on_drop: false }`
[INFO] [stdout] ec85dc568359cf71967c12d34f7231740065991ae9cbd19ee542d6cb3bebf686
[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=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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "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] 715f05b3173f473c1170b88c43fd2abc87d7823a95901e48ea29eaa224cf02cf
[INFO] running `Command { std: "docker" "start" "-a" "715f05b3173f473c1170b88c43fd2abc87d7823a95901e48ea29eaa224cf02cf", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde v1.0.80
[INFO] [stderr]    Compiling num-traits v0.2.6
[INFO] [stderr]     Checking half v1.3.0
[INFO] [stderr]     Checking dtoa v0.4.3
[INFO] [stderr]     Checking yaml-rust v0.4.2
[INFO] [stderr]    Compiling syn v0.15.21
[INFO] [stderr]     Checking num-integer v0.1.39
[INFO] [stderr]     Checking chrono v0.4.6
[INFO] [stderr]     Checking serde_cbor v0.9.0
[INFO] [stderr]     Checking serde_yaml v0.8.7
[INFO] [stderr]     Checking serde_json v1.0.33
[INFO] [stderr]    Compiling serde_derive v1.0.80
[INFO] [stderr]     Checking flut v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:89:17
[INFO] [stdout]    |
[INFO] [stdout] 89 |             let mut socket = UdpSocket::bind(format!("127.0.0.1:{}", port)).expect("udp socket could not get created");
[INFO] [stdout]    |                 ----^^^^^^
[INFO] [stdout]    |                 |
[INFO] [stdout]    |                 help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:89:17
[INFO] [stdout]    |
[INFO] [stdout] 89 |             let mut socket = UdpSocket::bind(format!("127.0.0.1:{}", port)).expect("udp socket could not get created");
[INFO] [stdout]    |                 ----^^^^^^
[INFO] [stdout]    |                 |
[INFO] [stdout]    |                 help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 28.73s
[INFO] running `Command { std: "docker" "inspect" "715f05b3173f473c1170b88c43fd2abc87d7823a95901e48ea29eaa224cf02cf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "715f05b3173f473c1170b88c43fd2abc87d7823a95901e48ea29eaa224cf02cf", kill_on_drop: false }`
[INFO] [stdout] 715f05b3173f473c1170b88c43fd2abc87d7823a95901e48ea29eaa224cf02cf