[INFO] cloning repository https://github.com/rust-real-time-os/os_lab
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/rust-real-time-os/os_lab" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-real-time-os%2Fos_lab", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-real-time-os%2Fos_lab'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1582d86b62794a047c7a3c6c22bea4a7f3ad8efc
[INFO] checking rust-real-time-os/os_lab/1582d86b62794a047c7a3c6c22bea4a7f3ad8efc against master#7c4ac0603e9ee5295bc802c90575391288a69a8a for pr-124728
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frust-real-time-os%2Fos_lab" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/rust-real-time-os/os_lab on toolchain 7c4ac0603e9ee5295bc802c90575391288a69a8a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7c4ac0603e9ee5295bc802c90575391288a69a8a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/rust-real-time-os/os_lab
[INFO] finished tweaking git repo https://github.com/rust-real-time-os/os_lab
[INFO] tweaked toml for git repo https://github.com/rust-real-time-os/os_lab written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/rust-real-time-os/os_lab already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7c4ac0603e9ee5295bc802c90575391288a69a8a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:99613afd962a8cfa530ec1899472a458bd015a1ab0af876cf7eb06f6006d81ea" "/opt/rustwide/cargo-home/bin/cargo" "+7c4ac0603e9ee5295bc802c90575391288a69a8a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 03f691a8f935caa870d3d53d63f7a9d9ee2c0f9e3e9ad61109991c0f25745fc0
[INFO] running `Command { std: "docker" "start" "-a" "03f691a8f935caa870d3d53d63f7a9d9ee2c0f9e3e9ad61109991c0f25745fc0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "03f691a8f935caa870d3d53d63f7a9d9ee2c0f9e3e9ad61109991c0f25745fc0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "03f691a8f935caa870d3d53d63f7a9d9ee2c0f9e3e9ad61109991c0f25745fc0", kill_on_drop: false }`
[INFO] [stdout] 03f691a8f935caa870d3d53d63f7a9d9ee2c0f9e3e9ad61109991c0f25745fc0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:99613afd962a8cfa530ec1899472a458bd015a1ab0af876cf7eb06f6006d81ea" "/opt/rustwide/cargo-home/bin/cargo" "+7c4ac0603e9ee5295bc802c90575391288a69a8a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 74a97e8e49effe1dc61828e178d43f27df0c5bae4a02c31cb9ecd0ab28ad4c6d
[INFO] running `Command { std: "docker" "start" "-a" "74a97e8e49effe1dc61828e178d43f27df0c5bae4a02c31cb9ecd0ab28ad4c6d", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.139
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking ppv-lite86 v0.2.17
[INFO] [stderr]     Checking getrandom v0.2.8
[INFO] [stderr]     Checking rand_core v0.6.4
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.5
[INFO] [stderr]     Checking linked_list v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `predicate`
[INFO] [stdout]    --> src/double_linked_list.rs:268:34
[INFO] [stdout]     |
[INFO] [stdout] 268 |     pub fn find_mut<P>(&mut self,predicate:P)->Option<&mut T> where P:Fn(&T) -> bool{
[INFO] [stdout]     |                                  ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_predicate`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]   --> src/double_linked_list.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct Node<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `predicate`
[INFO] [stdout]    --> src/double_linked_list.rs:268:34
[INFO] [stdout]     |
[INFO] [stdout] 268 |     pub fn find_mut<P>(&mut self,predicate:P)->Option<&mut T> where P:Fn(&T) -> bool{
[INFO] [stdout]     |                                  ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_predicate`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]   --> src/double_linked_list.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct Node<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.36s
[INFO] running `Command { std: "docker" "inspect" "74a97e8e49effe1dc61828e178d43f27df0c5bae4a02c31cb9ecd0ab28ad4c6d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "74a97e8e49effe1dc61828e178d43f27df0c5bae4a02c31cb9ecd0ab28ad4c6d", kill_on_drop: false }`
[INFO] [stdout] 74a97e8e49effe1dc61828e178d43f27df0c5bae4a02c31cb9ecd0ab28ad4c6d