[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 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fricardopieper%2Frust-concurrency-tests" "/workspace/builds/worker-51/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-51/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ricardopieper/rust-concurrency-tests on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "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-51/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" "+1.60.0" "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-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 470587141d19617a03a7258541fb61d9e1ce278fd485a5788eeb7b410d239a25
[INFO] running `Command { std: "docker" "start" "-a" "470587141d19617a03a7258541fb61d9e1ce278fd485a5788eeb7b410d239a25", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "470587141d19617a03a7258541fb61d9e1ce278fd485a5788eeb7b410d239a25", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "470587141d19617a03a7258541fb61d9e1ce278fd485a5788eeb7b410d239a25", kill_on_drop: false }`
[INFO] [stdout] 470587141d19617a03a7258541fb61d9e1ce278fd485a5788eeb7b410d239a25
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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=warn" "-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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2750866ff6d68c9c3f7d6485d897834f5b91657e66e4101871ea24b0d4a8bd97
[INFO] running `Command { std: "docker" "start" "-a" "2750866ff6d68c9c3f7d6485d897834f5b91657e66e4101871ea24b0d4a8bd97", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rand_core v0.4.0
[INFO] [stderr]    Compiling autocfg v0.1.2
[INFO] [stderr]    Compiling libc v0.2.51
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.3
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[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 31.59s
[INFO] running `Command { std: "docker" "inspect" "2750866ff6d68c9c3f7d6485d897834f5b91657e66e4101871ea24b0d4a8bd97", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2750866ff6d68c9c3f7d6485d897834f5b91657e66e4101871ea24b0d4a8bd97", kill_on_drop: false }`
[INFO] [stdout] 2750866ff6d68c9c3f7d6485d897834f5b91657e66e4101871ea24b0d4a8bd97
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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=warn" "-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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 54825c0b82b1415a7479d2e16c88a1f70ba6bc371b8912a85810fe9ae370e7df
[INFO] running `Command { std: "docker" "start" "-a" "54825c0b82b1415a7479d2e16c88a1f70ba6bc371b8912a85810fe9ae370e7df", 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] [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: 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: 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: 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: 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: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.04s
[INFO] running `Command { std: "docker" "inspect" "54825c0b82b1415a7479d2e16c88a1f70ba6bc371b8912a85810fe9ae370e7df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "54825c0b82b1415a7479d2e16c88a1f70ba6bc371b8912a85810fe9ae370e7df", kill_on_drop: false }`
[INFO] [stdout] 54825c0b82b1415a7479d2e16c88a1f70ba6bc371b8912a85810fe9ae370e7df
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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=warn" "-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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] d72860b8e170535386aad5730b95bf5c7085235581c0430a23a93f01f474b1f2
[INFO] running `Command { std: "docker" "start" "-a" "d72860b8e170535386aad5730b95bf5c7085235581c0430a23a93f01f474b1f2", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]   --> src/coarse_grained_linked_set.rs:86:17
[INFO] [stderr]    |
[INFO] [stderr] 86 |                 mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stderr]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/coarse_grained_linked_set.rs:137:29
[INFO] [stderr]     |
[INFO] [stderr] 137 | ...                   mem::replace(&mut prev_node.next, Some(current_node));
[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: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/coarse_grained_linked_set.rs:141:25
[INFO] [stderr]     |
[INFO] [stderr] 141 |                         mem::replace(&mut prev_node.next, current);
[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: 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` (bin "rust-concurrency-tests") generated 3 warnings (3 duplicates)
[INFO] [stderr] warning: `rust-concurrency-tests` (bin "rust-concurrency-tests" test) generated 3 warnings (3 duplicates)
[INFO] [stderr] warning: `rust-concurrency-tests` (test "linked_set_tests") generated 7 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.70s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_concurrency_tests-9a85ce8854045df9)
[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] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_concurrency_tests-e00a10b3e52028d9)
[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] [stderr]      Running tests/linked_set_tests.rs (/opt/rustwide/target/debug/deps/linked_set_tests-d6c2a8fea9106e46)
[INFO] [stdout] 
[INFO] [stdout] running 7 tests
[INFO] [stdout] test adding_same_item_has_no_effect ... ok
[INFO] [stdout] test adds_and_removes_root ... ok
[INFO] [stdout] test adds_item ... ok
[INFO] [stdout] test adds_multiple_items_and_removes_everything_back_to_front ... ok
[INFO] [stdout] test adds_multiple_items_and_removes_everything_front_to_back ... ok
[INFO] [stdout] test adds_multiple_items_and_removes_everything_no_particular_order ... ok
[INFO] [stdout] test adds_root_and_fails_to_remove ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[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" "d72860b8e170535386aad5730b95bf5c7085235581c0430a23a93f01f474b1f2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d72860b8e170535386aad5730b95bf5c7085235581c0430a23a93f01f474b1f2", kill_on_drop: false }`
[INFO] [stdout] d72860b8e170535386aad5730b95bf5c7085235581c0430a23a93f01f474b1f2