[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] checking ricardopieper/rust-concurrency-tests against master#cced03bfd61a304243a34504618ecec86c17063f for pr-157082
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fricardopieper%2Frust-concurrency-tests" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[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-3-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/ricardopieper/rust-concurrency-tests on toolchain cced03bfd61a304243a34504618ecec86c17063f
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cced03bfd61a304243a34504618ecec86c17063f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/ricardopieper/rust-concurrency-tests already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+cced03bfd61a304243a34504618ecec86c17063f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3e793bdf10248eb2ddbd6b0faebed8155c11b4589982e2893733958d93e8d540" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33
[INFO] running `Command { std: "docker" "start" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33" "/opt/rustwide/cargo-home/bin/cargo" "+cced03bfd61a304243a34504618ecec86c17063f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-w" "/opt/rustwide/workdir" "--user" "0:0" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33" "/opt/rustwide/cargo-home/bin/cargo" "+cced03bfd61a304243a34504618ecec86c17063f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]     Checking 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: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let _ = mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 137 |                             let _ = mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                             +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         let _ = mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         +++++++
[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: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let _ = mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 137 |                             let _ = mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                             +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         let _ = mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         +++++++
[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: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let _ = mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 137 |                             let _ = mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                             +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         let _ = mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         +++++++
[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: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let _ = mem::replace(&mut self.root, Some(Box::new(new_node)));
[INFO] [stdout]    |                 +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 137 |                             let _ = mem::replace(&mut prev_node.next, Some(current_node));
[INFO] [stdout]     |                             +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 141 |                         let _ = mem::replace(&mut prev_node.next, current);
[INFO] [stdout]     |                         +++++++
[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)]` (part of `#[warn(unused)]`) 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] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.45s
[INFO] running `Command { std: "docker" "inspect" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33", kill_on_drop: false }`
[INFO] [stdout] d5568f64ead4ec39eb6909ea2154cdabf16fe2bbffd8ba5c189802244a2c0a33