[INFO] cloning repository https://github.com/Sieciechu/rust-test
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Sieciechu/rust-test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSieciechu%2Frust-test", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSieciechu%2Frust-test'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 49952d34665dec33b6a5eacec6c23918c6795805
[INFO] checking Sieciechu/rust-test against master#36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923 for pr-81863
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSieciechu%2Frust-test" "/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/Sieciechu/rust-test on toolchain 36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Sieciechu/rust-test
[INFO] finished tweaking git repo https://github.com/Sieciechu/rust-test
[INFO] tweaked toml for git repo https://github.com/Sieciechu/rust-test written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/Sieciechu/rust-test already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923" "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" "rustops/crates-build-env@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 62f8b385883ad982413fc53d23cb373fb019e480640f39359d5d7e8ceb96812d
[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" "62f8b385883ad982413fc53d23cb373fb019e480640f39359d5d7e8ceb96812d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "62f8b385883ad982413fc53d23cb373fb019e480640f39359d5d7e8ceb96812d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "62f8b385883ad982413fc53d23cb373fb019e480640f39359d5d7e8ceb96812d", kill_on_drop: false }`
[INFO] [stdout] 62f8b385883ad982413fc53d23cb373fb019e480640f39359d5d7e8ceb96812d
[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" "rustops/crates-build-env@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+36ecbc94eb6be90bc38b2d0fdd4bfac3f34d9923" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5a158903e1a1724d6fb7fd9cb5cdc9656758391333a819b74ced7fd0b6946745
[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" "5a158903e1a1724d6fb7fd9cb5cdc9656758391333a819b74ced7fd0b6946745", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_core v0.4.0
[INFO] [stderr]    Compiling autocfg v0.1.2
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling libc v0.2.48
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand_jitter v0.1.0
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling rand_pcg v0.1.1
[INFO] [stderr]     Checking rand_os v0.1.1
[INFO] [stderr]     Checking add_one v0.1.0 (/opt/rustwide/workdir/add_one)
[INFO] [stdout] error[E0594]: cannot assign to `head.next` which is behind a `&` reference
[INFO] [stdout]   --> add_one/src/lib.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut head: &Self = &self;
[INFO] [stdout]    |                               ----- help: consider changing this to be a mutable reference: `&mut self`
[INFO] [stdout] ...
[INFO] [stdout] 26 |         head.next = Some(n); // does not work
[INFO] [stdout]    |         ^^^^^^^^^ `head` is a `&` reference, so the data it refers to cannot be written
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `add_one`
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0594`.
[INFO] [stdout] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0594]: cannot assign to `head.next` which is behind a `&` reference
[INFO] [stdout]   --> add_one/src/lib.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut head: &Self = &self;
[INFO] [stdout]    |                               ----- help: consider changing this to be a mutable reference: `&mut self`
[INFO] [stdout] ...
[INFO] [stdout] 26 |         head.next = Some(n); // does not work
[INFO] [stdout]    |         ^^^^^^^^^ `head` is a `&` reference, so the data it refers to cannot be written
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0594`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "5a158903e1a1724d6fb7fd9cb5cdc9656758391333a819b74ced7fd0b6946745", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5a158903e1a1724d6fb7fd9cb5cdc9656758391333a819b74ced7fd0b6946745", kill_on_drop: false }`
[INFO] [stdout] 5a158903e1a1724d6fb7fd9cb5cdc9656758391333a819b74ced7fd0b6946745