[INFO] fetching crate jec-rccow 0.1.0...
[INFO] checking jec-rccow-0.1.0 against try#b2f80f6008cdafc35b4472bd46afa16cc6b0cd63 for pr-79470
[INFO] extracting crate jec-rccow 0.1.0 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate jec-rccow 0.1.0 on toolchain b2f80f6008cdafc35b4472bd46afa16cc6b0cd63
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate jec-rccow 0.1.0
[INFO] finished tweaking crates.io crate jec-rccow 0.1.0
[INFO] tweaked toml for crates.io crate jec-rccow 0.1.0 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 27d57ee6a973a68ef2f78c5ec128f253263354f2e0696e67e69a2b961a22ff32
[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" "27d57ee6a973a68ef2f78c5ec128f253263354f2e0696e67e69a2b961a22ff32", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "27d57ee6a973a68ef2f78c5ec128f253263354f2e0696e67e69a2b961a22ff32", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "27d57ee6a973a68ef2f78c5ec128f253263354f2e0696e67e69a2b961a22ff32", kill_on_drop: false }`
[INFO] [stdout] 27d57ee6a973a68ef2f78c5ec128f253263354f2e0696e67e69a2b961a22ff32
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "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] bc921016f304fe11b36e76607d37d98a97e6ef689056f2d1e77b1706bc78f48c
[INFO] running `Command { std: "docker" "start" "-a" "bc921016f304fe11b36e76607d37d98a97e6ef689056f2d1e77b1706bc78f48c", kill_on_drop: false }`
[INFO] [stderr]     Checking jec-rccow v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/lib.rs:73:13
[INFO] [stdout]    |
[INFO] [stdout] 73 |         let mut a = RcCow::new(5i32);
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/lib.rs:77:13
[INFO] [stdout]    |
[INFO] [stdout] 77 |         let mut c = b.clone();
[INFO] [stdout]    |             ----^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.25s
[INFO] running `Command { std: "docker" "inspect" "bc921016f304fe11b36e76607d37d98a97e6ef689056f2d1e77b1706bc78f48c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bc921016f304fe11b36e76607d37d98a97e6ef689056f2d1e77b1706bc78f48c", kill_on_drop: false }`
[INFO] [stdout] bc921016f304fe11b36e76607d37d98a97e6ef689056f2d1e77b1706bc78f48c