[INFO] cloning repository https://github.com/ezhang7423/understanding-borrowing
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ezhang7423/understanding-borrowing" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fezhang7423%2Funderstanding-borrowing", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fezhang7423%2Funderstanding-borrowing'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 03a3795c2b9e976093ec6a7bca7f8a1b65424247
[INFO] checking ezhang7423/understanding-borrowing against master#8007b506ac5da629f223b755f5a5391edd5f6d01 for pr-88041
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fezhang7423%2Funderstanding-borrowing" "/workspace/builds/worker-78/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-78/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ezhang7423/understanding-borrowing on toolchain 8007b506ac5da629f223b755f5a5391edd5f6d01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ezhang7423/understanding-borrowing
[INFO] finished tweaking git repo https://github.com/ezhang7423/understanding-borrowing
[INFO] tweaked toml for git repo https://github.com/ezhang7423/understanding-borrowing written to /workspace/builds/worker-78/source/Cargo.toml
[INFO] crate git repo https://github.com/ezhang7423/understanding-borrowing already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-78/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-78/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3cb94df290b2f8413addff0f1879efd2766a09da9b68ffb0e815f54449e33d5b
[INFO] running `Command { std: "docker" "start" "-a" "3cb94df290b2f8413addff0f1879efd2766a09da9b68ffb0e815f54449e33d5b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3cb94df290b2f8413addff0f1879efd2766a09da9b68ffb0e815f54449e33d5b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3cb94df290b2f8413addff0f1879efd2766a09da9b68ffb0e815f54449e33d5b", kill_on_drop: false }`
[INFO] [stdout] 3cb94df290b2f8413addff0f1879efd2766a09da9b68ffb0e815f54449e33d5b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-78/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-78/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ec555a910fd342ab54411526f58b887f65d0327aacc727ecfc95f081c9b2ab22
[INFO] running `Command { std: "docker" "start" "-a" "ec555a910fd342ab54411526f58b887f65d0327aacc727ecfc95f081c9b2ab22", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking understanding-borrowing v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: value assigned to `y` is never read
[INFO] [stdout]  --> src/main.rs:3:13
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut y = x;
[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 `y` is never read
[INFO] [stdout]  --> src/main.rs:3:13
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut y = x;
[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] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.94s
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "ec555a910fd342ab54411526f58b887f65d0327aacc727ecfc95f081c9b2ab22", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ec555a910fd342ab54411526f58b887f65d0327aacc727ecfc95f081c9b2ab22", kill_on_drop: false }`
[INFO] [stdout] ec555a910fd342ab54411526f58b887f65d0327aacc727ecfc95f081c9b2ab22