[INFO] cloning repository https://github.com/domsim1/rusty-old-maid
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/domsim1/rusty-old-maid" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdomsim1%2Frusty-old-maid", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdomsim1%2Frusty-old-maid'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a105dc884329ba8d8ca5ac77a80a13b515f866d1
[INFO] testing domsim1/rusty-old-maid against master#a77da2d454e6caa227a85b16410b95f93495e7e0 for pr-91031
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdomsim1%2Frusty-old-maid" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/domsim1/rusty-old-maid on toolchain a77da2d454e6caa227a85b16410b95f93495e7e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/domsim1/rusty-old-maid
[INFO] finished tweaking git repo https://github.com/domsim1/rusty-old-maid
[INFO] tweaked toml for git repo https://github.com/domsim1/rusty-old-maid written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/domsim1/rusty-old-maid already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "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-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "metadata" "--no-deps" "--format-version=1", 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] fa2cc409ca17a6ebdf8a2e5d1d4d42703d18f00da958458c98e42f33e4c3e131
[INFO] running `Command { std: "docker" "start" "-a" "fa2cc409ca17a6ebdf8a2e5d1d4d42703d18f00da958458c98e42f33e4c3e131", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fa2cc409ca17a6ebdf8a2e5d1d4d42703d18f00da958458c98e42f33e4c3e131", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fa2cc409ca17a6ebdf8a2e5d1d4d42703d18f00da958458c98e42f33e4c3e131", kill_on_drop: false }`
[INFO] [stdout] fa2cc409ca17a6ebdf8a2e5d1d4d42703d18f00da958458c98e42f33e4c3e131
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9e21d01b48f467e739b8ff553c149e176484eb7f1af32001b186677507f10830
[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" "9e21d01b48f467e739b8ff553c149e176484eb7f1af32001b186677507f10830", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.74
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling ppv-lite86 v0.2.8
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling old-maid v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/fiftytwo.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |         &self.deck.shuffle(&mut thread_rng());
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 138 |         let _ = &self.deck.shuffle(&mut thread_rng());
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/fiftytwo.rs:143:13
[INFO] [stdout]     |
[INFO] [stdout] 143 |             &self.hands.push(Vec::new());
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 143 |             let _ = &self.hands.push(Vec::new());
[INFO] [stdout]     |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 10.30s
[INFO] running `Command { std: "docker" "inspect" "9e21d01b48f467e739b8ff553c149e176484eb7f1af32001b186677507f10830", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9e21d01b48f467e739b8ff553c149e176484eb7f1af32001b186677507f10830", kill_on_drop: false }`
[INFO] [stdout] 9e21d01b48f467e739b8ff553c149e176484eb7f1af32001b186677507f10830
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 54d12fc285774d0c858e74a91bd1902cbfebd253cda0493cf5abec9cee369b36
[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" "54d12fc285774d0c858e74a91bd1902cbfebd253cda0493cf5abec9cee369b36", kill_on_drop: false }`
[INFO] [stderr]    Compiling old-maid v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/fiftytwo.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |         &self.deck.shuffle(&mut thread_rng());
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 138 |         let _ = &self.deck.shuffle(&mut thread_rng());
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/fiftytwo.rs:143:13
[INFO] [stdout]     |
[INFO] [stdout] 143 |             &self.hands.push(Vec::new());
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 143 |             let _ = &self.hands.push(Vec::new());
[INFO] [stdout]     |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.19s
[INFO] running `Command { std: "docker" "inspect" "54d12fc285774d0c858e74a91bd1902cbfebd253cda0493cf5abec9cee369b36", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "54d12fc285774d0c858e74a91bd1902cbfebd253cda0493cf5abec9cee369b36", kill_on_drop: false }`
[INFO] [stdout] 54d12fc285774d0c858e74a91bd1902cbfebd253cda0493cf5abec9cee369b36
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 1c8d7e01e57e22fbd99c9b88e6fd833f7c0985e30609c5949737eb3be489527b
[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" "1c8d7e01e57e22fbd99c9b88e6fd833f7c0985e30609c5949737eb3be489527b", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: unused borrow that must be used
[INFO] [stdout] running 0 tests
[INFO] [stderr]    --> src/fiftytwo.rs:138:9
[INFO] [stdout] 
[INFO] [stderr]     |
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 138 |         &self.deck.shuffle(&mut thread_rng());
[INFO] [stdout] 
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]     |
[INFO] [stderr] 138 |         let _ = &self.deck.shuffle(&mut thread_rng());
[INFO] [stderr]     |         +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: unused borrow that must be used
[INFO] [stderr]    --> src/fiftytwo.rs:143:13
[INFO] [stderr]     |
[INFO] [stderr] 143 |             &self.hands.push(Vec::new());
[INFO] [stderr]     |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stderr]     |
[INFO] [stderr] help: use `let _ = ...` to ignore the resulting value
[INFO] [stderr]     |
[INFO] [stderr] 143 |             let _ = &self.hands.push(Vec::new());
[INFO] [stderr]     |             +++++++
[INFO] [stderr] 
[INFO] [stderr] warning: `old-maid` (bin "old-maid" test) generated 2 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/old_maid-31adbfb2a1aed4f7)
[INFO] running `Command { std: "docker" "inspect" "1c8d7e01e57e22fbd99c9b88e6fd833f7c0985e30609c5949737eb3be489527b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1c8d7e01e57e22fbd99c9b88e6fd833f7c0985e30609c5949737eb3be489527b", kill_on_drop: false }`
[INFO] [stdout] 1c8d7e01e57e22fbd99c9b88e6fd833f7c0985e30609c5949737eb3be489527b