[INFO] cloning repository https://github.com/corvuslabs/grammar-fuzzer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/corvuslabs/grammar-fuzzer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcorvuslabs%2Fgrammar-fuzzer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcorvuslabs%2Fgrammar-fuzzer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 2e0dd7d51a95ef0e477fdfadcd7c80e5f67e3733
[INFO] checking corvuslabs/grammar-fuzzer against try#9cfe725f0995b018340c519db1b2f3cf8a7e0631 for pr-81174
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcorvuslabs%2Fgrammar-fuzzer" "/workspace/builds/worker-5/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/corvuslabs/grammar-fuzzer on toolchain 9cfe725f0995b018340c519db1b2f3cf8a7e0631
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/corvuslabs/grammar-fuzzer
[INFO] finished tweaking git repo https://github.com/corvuslabs/grammar-fuzzer
[INFO] tweaked toml for git repo https://github.com/corvuslabs/grammar-fuzzer written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate git repo https://github.com/corvuslabs/grammar-fuzzer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 200f749522b3e013f4d26eb017ec92267fa5928855230d8712a20992c05fc1ec
[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" "200f749522b3e013f4d26eb017ec92267fa5928855230d8712a20992c05fc1ec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "200f749522b3e013f4d26eb017ec92267fa5928855230d8712a20992c05fc1ec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "200f749522b3e013f4d26eb017ec92267fa5928855230d8712a20992c05fc1ec", kill_on_drop: false }`
[INFO] [stdout] 200f749522b3e013f4d26eb017ec92267fa5928855230d8712a20992c05fc1ec
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ca8e8f2211d229bb67cb1ac5d1a3ff51270184e4d1f8c644901bd2269725ec2b
[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" "ca8e8f2211d229bb67cb1ac5d1a3ff51270184e4d1f8c644901bd2269725ec2b", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]     Checking ppv-lite86 v0.2.8
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]     Checking grammar-fuzzer v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/fuzzer.rs:65:17
[INFO] [stdout]    |
[INFO] [stdout] 65 |                 std::mem::replace(node, new_subtree);
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/fuzzer.rs:65:17
[INFO] [stdout]    |
[INFO] [stdout] 65 |                 std::mem::replace(node, new_subtree);
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 17.56s
[INFO] running `Command { std: "docker" "inspect" "ca8e8f2211d229bb67cb1ac5d1a3ff51270184e4d1f8c644901bd2269725ec2b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ca8e8f2211d229bb67cb1ac5d1a3ff51270184e4d1f8c644901bd2269725ec2b", kill_on_drop: false }`
[INFO] [stdout] ca8e8f2211d229bb67cb1ac5d1a3ff51270184e4d1f8c644901bd2269725ec2b