[INFO] fetching crate koi-gc 0.1.0...
[INFO] testing koi-gc-0.1.0 against 1.99.0-beta.1 for beta-1.99-5
[INFO] extracting crate koi-gc 0.1.0 into /workspace/builds/worker-4-tc2/source
[INFO] started tweaking crates.io crate koi-gc 0.1.0
[INFO] finished tweaking crates.io crate koi-gc 0.1.0
[INFO] tweaked toml for crates.io crate koi-gc 0.1.0 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate koi-gc 0.1.0 on toolchain 1.99.0-beta.1
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.99.0-beta.1" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate koi-gc 0.1.0 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" "+1.99.0-beta.1" "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-4-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:8683fc1fc2eb5c9ac98e0d076ab094b2ffac7f99da555d2b6a2e27f346de2ec7" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7
[INFO] running `Command { std: "docker" "start" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", 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" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", 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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.1" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling koi-gc v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.46s
[INFO] running `Command { std: "docker" "inspect" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", 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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.1" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling koi-gc v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `visitor`
[INFO] [stdout]    --> src/lib.rs:486:29
[INFO] [stdout]     |
[INFO] [stdout] 486 |             fn visit(&self, visitor: &mut dyn FnMut(&dyn GcInterface)) {}
[INFO] [stdout]     |                             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_visitor`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `data` is never read
[INFO] [stdout]    --> src/lib.rs:440:9
[INFO] [stdout]     |
[INFO] [stdout] 438 |     struct Leak<T> {
[INFO] [stdout]     |            ---- field in this struct
[INFO] [stdout] 439 |         cycle: RefCell<Option<Rc<Rc<Leak<T>>>>>,
[INFO] [stdout] 440 |         data: T,
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.53s
[INFO] running `Command { std: "docker" "inspect" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", 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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-w" "/opt/rustwide/workdir" "--user" "0:0" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7" "/opt/rustwide/cargo-home/bin/cargo" "+1.99.0-beta.1" "test" "--frozen", kill_on_drop: false }`
[INFO] [stderr] warning: unused variable: `visitor`
[INFO] [stderr]    --> src/lib.rs:486:29
[INFO] [stderr]     |
[INFO] [stderr] 486 |             fn visit(&self, visitor: &mut dyn FnMut(&dyn GcInterface)) {}
[INFO] [stderr]     |                             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_visitor`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field `data` is never read
[INFO] [stderr]    --> src/lib.rs:440:9
[INFO] [stderr]     |
[INFO] [stderr] 438 |     struct Leak<T> {
[INFO] [stderr]     |            ---- field in this struct
[INFO] [stderr] 439 |         cycle: RefCell<Option<Rc<Rc<Leak<T>>>>>,
[INFO] [stderr] 440 |         data: T,
[INFO] [stderr]     |         ^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `koi-gc` (lib test) generated 2 warnings (run `cargo fix --lib -p koi-gc --tests` to apply 1 suggestion)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/koi_gc-f2660c6714e3d381)
[INFO] [stdout] 
[INFO] [stdout] running 2 tests
[INFO] [stdout] test tests::not_leaked ... ok
[INFO] [stdout] test tests::test_cycle_collection ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests koi_gc
[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" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7", kill_on_drop: false }`
[INFO] [stdout] df99a8b8bd3275c6f6ab6f73abbfaca0c48d71327c23ea1d5434eed37b8460a7