[INFO] fetching crate fuzzcheck_mutators 0.4.1...
[INFO] checking fuzzcheck_mutators-0.4.1 against try#575650af7d7ca88602df28e39d27bf3e456c306e for pr-80579
[INFO] extracting crate fuzzcheck_mutators 0.4.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate fuzzcheck_mutators 0.4.1 on toolchain 575650af7d7ca88602df28e39d27bf3e456c306e
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+575650af7d7ca88602df28e39d27bf3e456c306e" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate fuzzcheck_mutators 0.4.1
[INFO] finished tweaking crates.io crate fuzzcheck_mutators 0.4.1
[INFO] tweaked toml for crates.io crate fuzzcheck_mutators 0.4.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate crates.io crate fuzzcheck_mutators 0.4.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+575650af7d7ca88602df28e39d27bf3e456c306e" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded fuzzcheck_mutators_derive v0.4.0
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+575650af7d7ca88602df28e39d27bf3e456c306e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5b565b278d88baf08789c0b2c782d56749304a6a0815ef4bfaf0b8bef10f291c
[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" "5b565b278d88baf08789c0b2c782d56749304a6a0815ef4bfaf0b8bef10f291c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5b565b278d88baf08789c0b2c782d56749304a6a0815ef4bfaf0b8bef10f291c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b565b278d88baf08789c0b2c782d56749304a6a0815ef4bfaf0b8bef10f291c", kill_on_drop: false }`
[INFO] [stdout] 5b565b278d88baf08789c0b2c782d56749304a6a0815ef4bfaf0b8bef10f291c
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+575650af7d7ca88602df28e39d27bf3e456c306e" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 64b460656974133e1fd02ea099ce48de24e526a1f4150fa95466e62e2a84d855
[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" "64b460656974133e1fd02ea099ce48de24e526a1f4150fa95466e62e2a84d855", kill_on_drop: false }`
[INFO] [stderr]     Checking fuzzcheck_traits v0.4.0
[INFO] [stderr]    Compiling fuzzcheck_mutators_derive v0.4.0
[INFO] [stderr]     Checking fastrand v1.3.4
[INFO] [stderr]     Checking fuzzcheck_mutators v0.4.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `fuzzcheck_mutators::fuzzcheck_derive_mutator`
[INFO] [stdout]  --> examples/vector_u8.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use fuzzcheck_mutators::fuzzcheck_derive_mutator;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `move_ref_pattern` has been stable since 1.48.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> examples/vector_u8.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(move_ref_pattern)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> examples/derive_struct.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |     for i in 0..10 {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `move_ref_pattern` has been stable since 1.48.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> examples/derive_enum.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(move_ref_pattern)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.65s
[INFO] running `Command { std: "docker" "inspect" "64b460656974133e1fd02ea099ce48de24e526a1f4150fa95466e62e2a84d855", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "64b460656974133e1fd02ea099ce48de24e526a1f4150fa95466e62e2a84d855", kill_on_drop: false }`
[INFO] [stdout] 64b460656974133e1fd02ea099ce48de24e526a1f4150fa95466e62e2a84d855