[INFO] cloning repository https://github.com/ricardopieper/rust-concurrency-tests
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ricardopieper/rust-concurrency-tests" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fricardopieper%2Frust-concurrency-tests", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fricardopieper%2Frust-concurrency-tests'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bf5d96403af158bfc1ad58a705530c2211efde87
[INFO] testing ricardopieper/rust-concurrency-tests against master#62efba8a050c64249dab942951bb28f710208bc8 for pr-90799
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fricardopieper%2Frust-concurrency-tests" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ricardopieper/rust-concurrency-tests on toolchain 62efba8a050c64249dab942951bb28f710208bc8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+62efba8a050c64249dab942951bb28f710208bc8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ricardopieper/rust-concurrency-tests
[INFO] finished tweaking git repo https://github.com/ricardopieper/rust-concurrency-tests
[INFO] tweaked toml for git repo https://github.com/ricardopieper/rust-concurrency-tests written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/ricardopieper/rust-concurrency-tests already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+62efba8a050c64249dab942951bb28f710208bc8" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "+62efba8a050c64249dab942951bb28f710208bc8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 15e44bf2e2e5b44503df4944eff57bada1b1f601ce5528123ce170ba82f20de6
[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" "15e44bf2e2e5b44503df4944eff57bada1b1f601ce5528123ce170ba82f20de6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "15e44bf2e2e5b44503df4944eff57bada1b1f601ce5528123ce170ba82f20de6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "15e44bf2e2e5b44503df4944eff57bada1b1f601ce5528123ce170ba82f20de6", kill_on_drop: false }`
[INFO] [stdout] 15e44bf2e2e5b44503df4944eff57bada1b1f601ce5528123ce170ba82f20de6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "+62efba8a050c64249dab942951bb28f710208bc8" "build" "--frozen" "--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] 80a82b625986597a659e94cd268164ac87fdc45e7ce29d5bd611896fe920d63d
[INFO] running `Command { std: "docker" "start" "-a" "80a82b625986597a659e94cd268164ac87fdc45e7ce29d5bd611896fe920d63d", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.51
[INFO] [stderr]    Compiling rand_jitter v0.1.3
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling rust-concurrency-tests v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 8.66s
[INFO] running `Command { std: "docker" "inspect" "80a82b625986597a659e94cd268164ac87fdc45e7ce29d5bd611896fe920d63d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "80a82b625986597a659e94cd268164ac87fdc45e7ce29d5bd611896fe920d63d", kill_on_drop: false }`
[INFO] [stdout] 80a82b625986597a659e94cd268164ac87fdc45e7ce29d5bd611896fe920d63d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "+62efba8a050c64249dab942951bb28f710208bc8" "test" "--frozen" "--no-run" "--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] df5323fd0c738a6d758a7c2547c643d01f1fda67c74c6dd9ce636e296fd281c5
[INFO] running `Command { std: "docker" "start" "-a" "df5323fd0c738a6d758a7c2547c643d01f1fda67c74c6dd9ce636e296fd281c5", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-concurrency-tests v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> tests/linked_set_tests.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]   |         ----^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/linked_set_tests.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/linked_set_tests.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/linked_set_tests.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/linked_set_tests.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/linked_set_tests.rs:83:9
[INFO] [stdout]    |
[INFO] [stdout] 83 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/linked_set_tests.rs:108:9
[INFO] [stdout]     |
[INFO] [stdout] 108 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stdout]     |         ----^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout]     |
[INFO] [stdout] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.90s
[INFO] running `Command { std: "docker" "inspect" "df5323fd0c738a6d758a7c2547c643d01f1fda67c74c6dd9ce636e296fd281c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "df5323fd0c738a6d758a7c2547c643d01f1fda67c74c6dd9ce636e296fd281c5", kill_on_drop: false }`
[INFO] [stdout] df5323fd0c738a6d758a7c2547c643d01f1fda67c74c6dd9ce636e296fd281c5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "+62efba8a050c64249dab942951bb28f710208bc8" "test" "--frozen", 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] 8622a5f7d1ba1a6983148680616dc67fe59cc78acded594ce10ba82a884c085a
[INFO] running `Command { std: "docker" "start" "-a" "8622a5f7d1ba1a6983148680616dc67fe59cc78acded594ce10ba82a884c085a", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout] running 0 tests
[INFO] [stderr]   --> src/coarse_grained_linked_set.rs:86:17
[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] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout] 
[INFO] [stderr]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stderr]    |
[INFO] [stdout] running 0 tests
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] 
[INFO] [stderr]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 
[INFO] [stdout] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout] 
[INFO] [stderr]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stdout] running 7 tests
[INFO] [stderr]     |
[INFO] [stdout] test adds_and_removes_root ... ok
[INFO] [stderr] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout] test adds_root_and_fails_to_remove ... ok
[INFO] [stderr]     |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] test adding_same_item_has_no_effect ... ok
[INFO] [stderr]     |
[INFO] [stdout] test adds_multiple_items_and_removes_everything_front_to_back ... ok
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] test adds_multiple_items_and_removes_everything_no_particular_order ... ok
[INFO] [stderr] 
[INFO] [stdout] test adds_multiple_items_and_removes_everything_back_to_front ... ok
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout] test adds_item ... ok
[INFO] [stderr]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stdout] 
[INFO] [stderr]     |
[INFO] [stdout] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
[INFO] [stderr] 141 |                         mem::replace(&mut prev_node.next, current);
[INFO] [stdout] 
[INFO] [stderr]     |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: `rust-concurrency-tests` (lib) generated 3 warnings
[INFO] [stderr] warning: `rust-concurrency-tests` (lib test) generated 3 warnings (3 duplicates)
[INFO] [stderr] warning: `rust-concurrency-tests` (bin "rust-concurrency-tests") generated 3 warnings (3 duplicates)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]  --> tests/linked_set_tests.rs:5:9
[INFO] [stderr]   |
[INFO] [stderr] 5 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]   |         ----^^^
[INFO] [stderr]   |         |
[INFO] [stderr]   |         help: remove this `mut`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/linked_set_tests.rs:24:9
[INFO] [stderr]    |
[INFO] [stderr] 24 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]    |         ----^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/linked_set_tests.rs:40:9
[INFO] [stderr]    |
[INFO] [stderr] 40 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]    |         ----^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/linked_set_tests.rs:49:9
[INFO] [stderr]    |
[INFO] [stderr] 49 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]    |         ----^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/linked_set_tests.rs:58:9
[INFO] [stderr]    |
[INFO] [stderr] 58 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]    |         ----^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> tests/linked_set_tests.rs:83:9
[INFO] [stderr]    |
[INFO] [stderr] 83 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]    |         ----^^^
[INFO] [stderr]    |         |
[INFO] [stderr]    |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> tests/linked_set_tests.rs:108:9
[INFO] [stderr]     |
[INFO] [stderr] 108 |     let mut set = CoarseLockLinkedSet::<i32>::new();
[INFO] [stderr]     |         ----^^^
[INFO] [stderr]     |         |
[INFO] [stderr]     |         help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: `rust-concurrency-tests` (test "linked_set_tests") generated 7 warnings
[INFO] [stderr] warning: `rust-concurrency-tests` (bin "rust-concurrency-tests" test) generated 3 warnings (3 duplicates)
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_concurrency_tests-d0a8ae70128df3a3)
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_concurrency_tests-51e064ba8971d312)
[INFO] [stderr]      Running tests/linked_set_tests.rs (/opt/rustwide/target/debug/deps/linked_set_tests-62c1fee82de5efc4)
[INFO] [stderr]    Doc-tests rust-concurrency-tests
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "8622a5f7d1ba1a6983148680616dc67fe59cc78acded594ce10ba82a884c085a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8622a5f7d1ba1a6983148680616dc67fe59cc78acded594ce10ba82a884c085a", kill_on_drop: false }`
[INFO] [stdout] 8622a5f7d1ba1a6983148680616dc67fe59cc78acded594ce10ba82a884c085a