[INFO] fetching crate fuzzcheck_mutators 0.6.0...
[INFO] checking fuzzcheck_mutators-0.6.0 against try#4a04890980766cc79878135f5ade8c0c4321e943 for pr-65819
[INFO] extracting crate fuzzcheck_mutators 0.6.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate fuzzcheck_mutators 0.6.0 on toolchain 4a04890980766cc79878135f5ade8c0c4321e943
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate fuzzcheck_mutators 0.6.0
[INFO] finished tweaking crates.io crate fuzzcheck_mutators 0.6.0
[INFO] tweaked toml for crates.io crate fuzzcheck_mutators 0.6.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate crates.io crate fuzzcheck_mutators 0.6.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "fetch" "--locked" "--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-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9a3e28eb35fbc0ae2af8d3e7a51efa6df750d58808798831c7015125f85de424
[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" "9a3e28eb35fbc0ae2af8d3e7a51efa6df750d58808798831c7015125f85de424", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9a3e28eb35fbc0ae2af8d3e7a51efa6df750d58808798831c7015125f85de424", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9a3e28eb35fbc0ae2af8d3e7a51efa6df750d58808798831c7015125f85de424", kill_on_drop: false }`
[INFO] [stdout] 9a3e28eb35fbc0ae2af8d3e7a51efa6df750d58808798831c7015125f85de424
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 89ecf5dd71d10dae5127389d1af76e70d2bfc13a9ba50ae06942c4855e3441d9
[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" "89ecf5dd71d10dae5127389d1af76e70d2bfc13a9ba50ae06942c4855e3441d9", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling decent-synquote-alternative v0.3.0
[INFO] [stderr]    Compiling fuzzcheck_mutators_derive v0.6.0
[INFO] [stderr]     Checking fuzzcheck_mutators v0.6.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the feature `generic_associated_types` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(generic_associated_types)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `generic_associated_types` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(generic_associated_types)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `int_bits_const` has been stable since 1.53.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(int_bits_const)]
[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: the feature `int_bits_const` has been stable since 1.53.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(int_bits_const)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> examples/vector_u8.rs:16:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     let mut m = Vec::<u8>::default_mutator();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> examples/derive_enum_check_results.rs:34:9
[INFO] [stdout]    |
[INFO] [stdout] 34 |     let mut m = X::default_mutator();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> examples/derive_struct.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut m = S::<u8, u8, u8>::default_mutator();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> examples/derive_enum.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut m = Vec::<SampleData<u8, Option<u8>, bool>>::default_mutator();
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` 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 12.95s
[INFO] running `Command { std: "docker" "inspect" "89ecf5dd71d10dae5127389d1af76e70d2bfc13a9ba50ae06942c4855e3441d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89ecf5dd71d10dae5127389d1af76e70d2bfc13a9ba50ae06942c4855e3441d9", kill_on_drop: false }`
[INFO] [stdout] 89ecf5dd71d10dae5127389d1af76e70d2bfc13a9ba50ae06942c4855e3441d9