[INFO] fetching crate stable-skiplist 0.1.1...
[INFO] checking stable-skiplist-0.1.1 against master#cfbc6d4cf1acbac5c025acf8ed68929caa551df3 for pr-75494-beta
[INFO] extracting crate stable-skiplist 0.1.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate stable-skiplist 0.1.1 on toolchain cfbc6d4cf1acbac5c025acf8ed68929caa551df3
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+cfbc6d4cf1acbac5c025acf8ed68929caa551df3" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate stable-skiplist 0.1.1
[INFO] finished tweaking crates.io crate stable-skiplist 0.1.1
[INFO] tweaked toml for crates.io crate stable-skiplist 0.1.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+cfbc6d4cf1acbac5c025acf8ed68929caa551df3" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+cfbc6d4cf1acbac5c025acf8ed68929caa551df3" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+cfbc6d4cf1acbac5c025acf8ed68929caa551df3" "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] 7cf25ddfe8ab8949ce202aca12ac539b663c2f40bb965204316e6e0203fdcd24
[INFO] running `Command { std: "docker" "start" "-a" "7cf25ddfe8ab8949ce202aca12ac539b663c2f40bb965204316e6e0203fdcd24", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7cf25ddfe8ab8949ce202aca12ac539b663c2f40bb965204316e6e0203fdcd24", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7cf25ddfe8ab8949ce202aca12ac539b663c2f40bb965204316e6e0203fdcd24", kill_on_drop: false }`
[INFO] [stdout] 7cf25ddfe8ab8949ce202aca12ac539b663c2f40bb965204316e6e0203fdcd24
[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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+cfbc6d4cf1acbac5c025acf8ed68929caa551df3" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7b47b272d50d6df4d1337b3473cd62de3087a13e7f2aabbc8cba43b4cbd5bca7
[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" "7b47b272d50d6df4d1337b3473cd62de3087a13e7f2aabbc8cba43b4cbd5bca7", kill_on_drop: false }`
[INFO] [stderr]     Checking stable-skiplist v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1415:9
[INFO] [stdout]      |
[INFO] [stdout] 1415 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1419:17
[INFO] [stdout]      |
[INFO] [stdout] 1419 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1421:13
[INFO] [stdout]      |
[INFO] [stdout] 1421 |             try!(write!(f, "{:?}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1430:9
[INFO] [stdout]      |
[INFO] [stdout] 1430 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1434:17
[INFO] [stdout]      |
[INFO] [stdout] 1434 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1436:13
[INFO] [stdout]      |
[INFO] [stdout] 1436 |             try!(write!(f, "{}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1356:9
[INFO] [stdout]      |
[INFO] [stdout] 1356 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1360:17
[INFO] [stdout]      |
[INFO] [stdout] 1360 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1362:13
[INFO] [stdout]      |
[INFO] [stdout] 1362 |             try!(write!(f, "({:?}, {:?})", k, v));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1373:9
[INFO] [stdout]      |
[INFO] [stdout] 1373 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1377:17
[INFO] [stdout]      |
[INFO] [stdout] 1377 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1379:13
[INFO] [stdout]      |
[INFO] [stdout] 1379 |             try!(write!(f, "({}, {})", k, v));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1156:9
[INFO] [stdout]      |
[INFO] [stdout] 1156 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1160:17
[INFO] [stdout]      |
[INFO] [stdout] 1160 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1162:13
[INFO] [stdout]      |
[INFO] [stdout] 1162 |             try!(write!(f, "{:?}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1171:9
[INFO] [stdout]      |
[INFO] [stdout] 1171 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1175:17
[INFO] [stdout]      |
[INFO] [stdout] 1175 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1177:13
[INFO] [stdout]      |
[INFO] [stdout] 1177 |             try!(write!(f, "{}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/ordered_skiplist.rs:44:18
[INFO] [stdout]    |
[INFO] [stdout] 44 |     compare: Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/ordered_skiplist.rs:81:24
[INFO] [stdout]    |
[INFO] [stdout] 81 |             })) as Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]    |                        ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/ordered_skiplist.rs:115:24
[INFO] [stdout]     |
[INFO] [stdout] 115 |             })) as Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]     |                        ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1415:9
[INFO] [stdout]      |
[INFO] [stdout] 1415 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1419:17
[INFO] [stdout]      |
[INFO] [stdout] 1419 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1421:13
[INFO] [stdout]      |
[INFO] [stdout] 1421 |             try!(write!(f, "{:?}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1430:9
[INFO] [stdout]      |
[INFO] [stdout] 1430 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1434:17
[INFO] [stdout]      |
[INFO] [stdout] 1434 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/ordered_skiplist.rs:1436:13
[INFO] [stdout]      |
[INFO] [stdout] 1436 |             try!(write!(f, "{}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1356:9
[INFO] [stdout]      |
[INFO] [stdout] 1356 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1360:17
[INFO] [stdout]      |
[INFO] [stdout] 1360 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1362:13
[INFO] [stdout]      |
[INFO] [stdout] 1362 |             try!(write!(f, "({:?}, {:?})", k, v));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1373:9
[INFO] [stdout]      |
[INFO] [stdout] 1373 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1377:17
[INFO] [stdout]      |
[INFO] [stdout] 1377 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skipmap.rs:1379:13
[INFO] [stdout]      |
[INFO] [stdout] 1379 |             try!(write!(f, "({}, {})", k, v));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1156:9
[INFO] [stdout]      |
[INFO] [stdout] 1156 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1160:17
[INFO] [stdout]      |
[INFO] [stdout] 1160 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1162:13
[INFO] [stdout]      |
[INFO] [stdout] 1162 |             try!(write!(f, "{:?}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1171:9
[INFO] [stdout]      |
[INFO] [stdout] 1171 |         try!(write!(f, "["));
[INFO] [stdout]      |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1175:17
[INFO] [stdout]      |
[INFO] [stdout] 1175 |                 try!(write!(f, ", "));
[INFO] [stdout]      |                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]     --> src/skiplist.rs:1177:13
[INFO] [stdout]      |
[INFO] [stdout] 1177 |             try!(write!(f, "{}", entry));
[INFO] [stdout]      |             ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/ordered_skiplist.rs:44:18
[INFO] [stdout]    |
[INFO] [stdout] 44 |     compare: Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/ordered_skiplist.rs:81:24
[INFO] [stdout]    |
[INFO] [stdout] 81 |             })) as Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]    |                        ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/ordered_skiplist.rs:115:24
[INFO] [stdout]     |
[INFO] [stdout] 115 |             })) as Box<Fn(&T, &T) -> Ordering>,
[INFO] [stdout]     |                        ^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T, &T) -> Ordering`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/ordered_skiplist.rs:236:17
[INFO] [stdout]     |
[INFO] [stdout] 236 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/ordered_skiplist.rs:241:9
[INFO] [stdout]     |
[INFO] [stdout] 241 |         mem::replace(&mut self.head, new_head);
[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/ordered_skiplist.rs:847:21
[INFO] [stdout]     |
[INFO] [stdout] 847 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:922:21
[INFO] [stdout]     |
[INFO] [stdout] 922 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:1347:17
[INFO] [stdout]      |
[INFO] [stdout] 1347 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:308:17
[INFO] [stdout]     |
[INFO] [stdout] 308 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |         mem::replace(&mut self.head, new_head);
[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/skipmap.rs:1255:17
[INFO] [stdout]      |
[INFO] [stdout] 1255 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:94:17
[INFO] [stdout]    |
[INFO] [stdout] 94 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:99:9
[INFO] [stdout]    |
[INFO] [stdout] 99 |         mem::replace(&mut self.head, new_head);
[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/skiplist.rs:567:21
[INFO] [stdout]     |
[INFO] [stdout] 567 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:863:21
[INFO] [stdout]     |
[INFO] [stdout] 863 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:1088:17
[INFO] [stdout]      |
[INFO] [stdout] 1088 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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: 34 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/ordered_skiplist.rs:236:17
[INFO] [stdout]     |
[INFO] [stdout] 236 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/ordered_skiplist.rs:241:9
[INFO] [stdout]     |
[INFO] [stdout] 241 |         mem::replace(&mut self.head, new_head);
[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/ordered_skiplist.rs:847:21
[INFO] [stdout]     |
[INFO] [stdout] 847 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:922:21
[INFO] [stdout]     |
[INFO] [stdout] 922 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/ordered_skiplist.rs:1347:17
[INFO] [stdout]      |
[INFO] [stdout] 1347 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:308:17
[INFO] [stdout]     |
[INFO] [stdout] 308 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skipmap.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |         mem::replace(&mut self.head, new_head);
[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/skipmap.rs:1255:17
[INFO] [stdout]      |
[INFO] [stdout] 1255 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:94:17
[INFO] [stdout]    |
[INFO] [stdout] 94 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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/skiplist.rs:99:9
[INFO] [stdout]    |
[INFO] [stdout] 99 |         mem::replace(&mut self.head, new_head);
[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/skiplist.rs:567:21
[INFO] [stdout]     |
[INFO] [stdout] 567 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:863:21
[INFO] [stdout]     |
[INFO] [stdout] 863 |                     mem::replace(&mut (*prev).next, mem::replace(&mut (*node).next, None));
[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/skiplist.rs:1088:17
[INFO] [stdout]      |
[INFO] [stdout] 1088 |                 mem::replace(&mut (*node).next, mem::replace(&mut next.next, None));
[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: 34 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.91s
[INFO] running `Command { std: "docker" "inspect" "7b47b272d50d6df4d1337b3473cd62de3087a13e7f2aabbc8cba43b4cbd5bca7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7b47b272d50d6df4d1337b3473cd62de3087a13e7f2aabbc8cba43b4cbd5bca7", kill_on_drop: false }`
[INFO] [stdout] 7b47b272d50d6df4d1337b3473cd62de3087a13e7f2aabbc8cba43b4cbd5bca7
