[INFO] crate skiplist 0.3.0 is already in cache
[INFO] checking skiplist-0.3.0 against master#74e80468347471779be6060d8d7d6d04e98e467f for pr-72788
[INFO] extracting crate skiplist 0.3.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate skiplist 0.3.0 on toolchain 74e80468347471779be6060d8d7d6d04e98e467f
[INFO] running `"/workspace/cargo-home/bin/cargo" "+74e80468347471779be6060d8d7d6d04e98e467f" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate skiplist 0.3.0
[INFO] finished tweaking crates.io crate skiplist 0.3.0
[INFO] tweaked toml for crates.io crate skiplist 0.3.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+74e80468347471779be6060d8d7d6d04e98e467f" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+74e80468347471779be6060d8d7d6d04e98e467f" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+74e80468347471779be6060d8d7d6d04e98e467f" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 259ce105e2cb48f1870899e0e668d55bf18608cfc67bacafb856833f286d85c4
[INFO] running `"docker" "start" "-a" "259ce105e2cb48f1870899e0e668d55bf18608cfc67bacafb856833f286d85c4"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling rayon-core v1.7.0
[INFO] [stderr]     Checking either v1.5.3
[INFO] [stderr]    Compiling syn v1.0.30
[INFO] [stderr]    Compiling num-traits v0.2.11
[INFO] [stderr]     Checking regex-automata v0.1.9
[INFO] [stderr]     Checking clap v2.33.1
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]     Checking serde_json v1.0.53
[INFO] [stderr]    Compiling cast v0.2.3
[INFO] [stderr]     Checking itertools v0.9.0
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking bstr v0.2.13
[INFO] [stderr]     Checking rand_pcg v0.2.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rayon v1.3.0
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking plotters v0.2.15
[INFO] [stderr]     Checking skiplist v0.3.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking csv v1.1.3
[INFO] [stderr]     Checking tinytemplate v1.1.0
[INFO] [stderr]     Checking criterion-plot v0.4.2
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/ordered_skiplist.rs:249:17
[INFO] [stderr]     |
[INFO] [stderr] 249 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/ordered_skiplist.rs:254:9
[INFO] [stderr]     |
[INFO] [stderr] 254 |         mem::replace(&mut self.head, new_head);
[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/ordered_skiplist.rs:882:21
[INFO] [stderr]     |
[INFO] [stderr] 882 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:961:21
[INFO] [stderr]     |
[INFO] [stderr] 961 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:1397:17
[INFO] [stderr]      |
[INFO] [stderr] 1397 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:95:17
[INFO] [stderr]    |
[INFO] [stderr] 95 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:100:9
[INFO] [stderr]     |
[INFO] [stderr] 100 |         mem::replace(&mut self.head, new_head);
[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/skiplist.rs:583:21
[INFO] [stderr]     |
[INFO] [stderr] 583 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:886:21
[INFO] [stderr]     |
[INFO] [stderr] 886 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:1120:17
[INFO] [stderr]      |
[INFO] [stderr] 1120 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:309:17
[INFO] [stderr]     |
[INFO] [stderr] 309 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:314:9
[INFO] [stderr]     |
[INFO] [stderr] 314 |         mem::replace(&mut self.head, new_head);
[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/skipmap.rs:1293:17
[INFO] [stderr]      |
[INFO] [stderr] 1293 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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: 13 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]    Compiling serde_derive v1.0.111
[INFO] [stderr]     Checking criterion v0.3.2
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/ordered_skiplist.rs:249:17
[INFO] [stderr]     |
[INFO] [stderr] 249 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/ordered_skiplist.rs:254:9
[INFO] [stderr]     |
[INFO] [stderr] 254 |         mem::replace(&mut self.head, new_head);
[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/ordered_skiplist.rs:882:21
[INFO] [stderr]     |
[INFO] [stderr] 882 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:961:21
[INFO] [stderr]     |
[INFO] [stderr] 961 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:1397:17
[INFO] [stderr]      |
[INFO] [stderr] 1397 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:95:17
[INFO] [stderr]    |
[INFO] [stderr] 95 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:100:9
[INFO] [stderr]     |
[INFO] [stderr] 100 |         mem::replace(&mut self.head, new_head);
[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/skiplist.rs:583:21
[INFO] [stderr]     |
[INFO] [stderr] 583 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:886:21
[INFO] [stderr]     |
[INFO] [stderr] 886 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:1120:17
[INFO] [stderr]      |
[INFO] [stderr] 1120 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:309:17
[INFO] [stderr]     |
[INFO] [stderr] 309 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:314:9
[INFO] [stderr]     |
[INFO] [stderr] 314 |         mem::replace(&mut self.head, new_head);
[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/skipmap.rs:1293:17
[INFO] [stderr]      |
[INFO] [stderr] 1293 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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: 13 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 53.42s
[INFO] running `"docker" "inspect" "259ce105e2cb48f1870899e0e668d55bf18608cfc67bacafb856833f286d85c4"`
[INFO] running `"docker" "rm" "-f" "259ce105e2cb48f1870899e0e668d55bf18608cfc67bacafb856833f286d85c4"`
[INFO] [stdout] 259ce105e2cb48f1870899e0e668d55bf18608cfc67bacafb856833f286d85c4