[INFO] cloning repository https://github.com/AJTJ/rust_problems
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/AJTJ/rust_problems" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAJTJ%2Frust_problems", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAJTJ%2Frust_problems'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 87f258cdf9eab9b23a01bba18486cecee34b3f8b
[INFO] checking AJTJ/rust_problems against master#a836d9b6413d9d593be6c09463ff8c4c70e56599 for pr-84037
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAJTJ%2Frust_problems" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/AJTJ/rust_problems on toolchain a836d9b6413d9d593be6c09463ff8c4c70e56599
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a836d9b6413d9d593be6c09463ff8c4c70e56599" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/AJTJ/rust_problems
[INFO] finished tweaking git repo https://github.com/AJTJ/rust_problems
[INFO] tweaked toml for git repo https://github.com/AJTJ/rust_problems written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/AJTJ/rust_problems already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a836d9b6413d9d593be6c09463ff8c4c70e56599" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+a836d9b6413d9d593be6c09463ff8c4c70e56599" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 04410fc2476bcd7b546e2500bada9765e932df226b6ede17a31c219549002c45
[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" "04410fc2476bcd7b546e2500bada9765e932df226b6ede17a31c219549002c45", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "04410fc2476bcd7b546e2500bada9765e932df226b6ede17a31c219549002c45", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "04410fc2476bcd7b546e2500bada9765e932df226b6ede17a31c219549002c45", kill_on_drop: false }`
[INFO] [stdout] 04410fc2476bcd7b546e2500bada9765e932df226b6ede17a31c219549002c45
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+a836d9b6413d9d593be6c09463ff8c4c70e56599" "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] 5380597298b7d2948832db36b172e1bc9a72fd863c607d5f284e5410147ef8d7
[INFO] running `Command { std: "docker" "start" "-a" "5380597298b7d2948832db36b172e1bc9a72fd863c607d5f284e5410147ef8d7", kill_on_drop: false }`
[INFO] [stderr] Checking rust_problems v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0277]: cannot add `Option