[INFO] fetching crate skiplist-rust 0.3.0...
[INFO] testing skiplist-rust-0.3.0 against beta-2026-04-21 for beta-1.96-2
[INFO] extracting crate skiplist-rust 0.3.0 into /workspace/builds/worker-1-tc2/source
[INFO] removed /workspace/builds/worker-1-tc2/source/rust-toolchain.toml
[INFO] started tweaking crates.io crate skiplist-rust 0.3.0
[INFO] finished tweaking crates.io crate skiplist-rust 0.3.0
[INFO] tweaked toml for crates.io crate skiplist-rust 0.3.0 written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate skiplist-rust 0.3.0 on toolchain beta-2026-04-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 14 packages to latest compatible versions
[INFO] [stderr]       Adding rand v0.8.6 (available: v0.10.1)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ca0edbd054e1df967d58d6a3384fa8dfbc1ad2296cf06015b78979e5c85ca776
[INFO] running `Command { std: "docker" "start" "-a" "ca0edbd054e1df967d58d6a3384fa8dfbc1ad2296cf06015b78979e5c85ca776", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ca0edbd054e1df967d58d6a3384fa8dfbc1ad2296cf06015b78979e5c85ca776", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ca0edbd054e1df967d58d6a3384fa8dfbc1ad2296cf06015b78979e5c85ca776", kill_on_drop: false }`
[INFO] [stdout] ca0edbd054e1df967d58d6a3384fa8dfbc1ad2296cf06015b78979e5c85ca776
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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" "RUSTDOCFLAGS=--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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bbb40e5102d00f0a15d93bea042494c07ec18b4ff30273348a2bdf204ca8185e
[INFO] running `Command { std: "docker" "start" "-a" "bbb40e5102d00f0a15d93bea042494c07ec18b4ff30273348a2bdf204ca8185e", kill_on_drop: false }`
[INFO] [stderr]    Compiling rand_chacha v0.3.1
[INFO] [stderr]    Compiling rand v0.8.6
[INFO] [stderr]    Compiling skiplist-rust v0.3.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: struct `SkipList` is never constructed
[INFO] [stdout]    --> src/lib.rs:245:8
[INFO] [stdout]     |
[INFO] [stdout] 245 | struct SkipList<K: Ord + Debug + Default> {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `insert`, `contains`, and `iter` are never used
[INFO] [stdout]    --> src/lib.rs:254:12
[INFO] [stdout]     |
[INFO] [stdout] 253 | impl<K: Ord + Debug + Default> SkipList<K> {
[INFO] [stdout]     | ------------------------------------------ associated items in this implementation
[INFO] [stdout] 254 |     pub fn new(arena: Arena) -> Self {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 261 |     pub fn insert(&self, key: K) {
[INFO] [stdout]     |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 268 |     pub fn contains(&self, key: &K) -> bool {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/lib.rs:274:17
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<'_, K> {
[INFO] [stdout]     |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.52s
[INFO] running `Command { std: "docker" "inspect" "bbb40e5102d00f0a15d93bea042494c07ec18b4ff30273348a2bdf204ca8185e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bbb40e5102d00f0a15d93bea042494c07ec18b4ff30273348a2bdf204ca8185e", kill_on_drop: false }`
[INFO] [stdout] bbb40e5102d00f0a15d93bea042494c07ec18b4ff30273348a2bdf204ca8185e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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" "RUSTDOCFLAGS=--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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1da3270d5749cf05e7b99587fed913886ba89939669fffe43380f58c024c055a
[INFO] running `Command { std: "docker" "start" "-a" "1da3270d5749cf05e7b99587fed913886ba89939669fffe43380f58c024c055a", kill_on_drop: false }`
[INFO] [stdout] warning: struct `SkipList` is never constructed
[INFO] [stdout]    --> src/lib.rs:245:8
[INFO] [stdout]     |
[INFO] [stdout] 245 | struct SkipList<K: Ord + Debug + Default> {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `insert`, `contains`, and `iter` are never used
[INFO] [stdout]    --> src/lib.rs:254:12
[INFO] [stdout]     |
[INFO] [stdout] 253 | impl<K: Ord + Debug + Default> SkipList<K> {
[INFO] [stdout]     | ------------------------------------------ associated items in this implementation
[INFO] [stdout] 254 |     pub fn new(arena: Arena) -> Self {
[INFO] [stdout]     |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 261 |     pub fn insert(&self, key: K) {
[INFO] [stdout]     |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 268 |     pub fn contains(&self, key: &K) -> bool {
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stdout]     |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/lib.rs:274:17
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<'_, K> {
[INFO] [stdout]     |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling skiplist-rust v0.3.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:313:13
[INFO] [stdout]     |
[INFO] [stdout] 313 |         let mut list = SkipList::new(arena);
[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: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/lib.rs:274:17
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 274 |     pub fn iter(&self) -> SkipListIterator<'_, K> {
[INFO] [stdout]     |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 1.11s
[INFO] running `Command { std: "docker" "inspect" "1da3270d5749cf05e7b99587fed913886ba89939669fffe43380f58c024c055a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1da3270d5749cf05e7b99587fed913886ba89939669fffe43380f58c024c055a", kill_on_drop: false }`
[INFO] [stdout] 1da3270d5749cf05e7b99587fed913886ba89939669fffe43380f58c024c055a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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" "RUSTDOCFLAGS=--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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 0c2910473553f5488607a2a1b219c67aff9f96a1657803893799391dd9cb54d8
[INFO] running `Command { std: "docker" "start" "-a" "0c2910473553f5488607a2a1b219c67aff9f96a1657803893799391dd9cb54d8", kill_on_drop: false }`
[INFO] [stderr] warning: struct `SkipList` is never constructed
[INFO] [stderr]    --> src/lib.rs:245:8
[INFO] [stderr]     |
[INFO] [stderr] 245 | struct SkipList<K: Ord + Debug + Default> {
[INFO] [stderr]     |        ^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: associated items `new`, `insert`, `contains`, and `iter` are never used
[INFO] [stderr]    --> src/lib.rs:254:12
[INFO] [stderr]     |
[INFO] [stderr] 253 | impl<K: Ord + Debug + Default> SkipList<K> {
[INFO] [stderr]     | ------------------------------------------ associated items in this implementation
[INFO] [stderr] 254 |     pub fn new(arena: Arena) -> Self {
[INFO] [stderr]     |            ^^^
[INFO] [stderr] ...
[INFO] [stderr] 261 |     pub fn insert(&self, key: K) {
[INFO] [stderr]     |            ^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 268 |     pub fn contains(&self, key: &K) -> bool {
[INFO] [stderr]     |            ^^^^^^^^
[INFO] [stderr] ...
[INFO] [stderr] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stderr]     |            ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/lib.rs:274:17
[INFO] [stderr]     |
[INFO] [stderr] 274 |     pub fn iter(&self) -> SkipListIterator<K> {
[INFO] [stderr]     |                 ^^^^^     ^^^^^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                 |
[INFO] [stderr]     |                 the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 274 |     pub fn iter(&self) -> SkipListIterator<'_, K> {
[INFO] [stderr]     |                                            +++
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/lib.rs:313:13
[INFO] [stderr]     |
[INFO] [stderr] 313 |         let mut list = SkipList::new(arena);
[INFO] [stderr]     |             ----^^^^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `skiplist-rust` (lib) generated 3 warnings (run `cargo fix --lib -p skiplist-rust` to apply 1 suggestion)
[INFO] [stderr] warning: `skiplist-rust` (lib test) generated 2 warnings (1 duplicate) (run `cargo fix --lib -p skiplist-rust --tests` to apply 1 suggestion)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.03s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/skiplist_rust-a67cc26da31da22f)
[INFO] [stdout] 
[INFO] [stdout] running 11 tests
[INFO] [stdout] test arena::test::test_arena_empty ... ok
[INFO] [stdout] test tests::test_empty ... ok
[INFO] [stdout] test tests::insert_and_lookup ... ok
[INFO] [stdout] test tests::test_concurrent_write ... ok
[INFO] [stdout] test arena::test::test_arena_simple ... ok
[INFO] [stdout] test tests::concurrent_without_threads ... ok
[INFO] [stdout] test tests::concurrent_1 ... ok
[INFO] [stdout] test tests::concurrent_2 ... ok
[INFO] [stdout] test tests::concurrent_5 ... ok
[INFO] [stdout] test tests::concurrent_3 ... ok
[INFO] [stdout] test tests::concurrent_4 ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 11 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 21.44s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests skiplist_rust
[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" "0c2910473553f5488607a2a1b219c67aff9f96a1657803893799391dd9cb54d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c2910473553f5488607a2a1b219c67aff9f96a1657803893799391dd9cb54d8", kill_on_drop: false }`
[INFO] [stdout] 0c2910473553f5488607a2a1b219c67aff9f96a1657803893799391dd9cb54d8
