[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#b2f80f6008cdafc35b4472bd46afa16cc6b0cd63 for pr-79470
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcorvuslabs%2Fgrammar-fuzzer" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/corvuslabs/grammar-fuzzer on toolchain b2f80f6008cdafc35b4472bd46afa16cc6b0cd63
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "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-4/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" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded lexical-core v0.6.7
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 48e14dc2a607acab01b08ee7f42f39b9c546a0286fd03b822570d7a661dade28
[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" "48e14dc2a607acab01b08ee7f42f39b9c546a0286fd03b822570d7a661dade28", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "48e14dc2a607acab01b08ee7f42f39b9c546a0286fd03b822570d7a661dade28", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "48e14dc2a607acab01b08ee7f42f39b9c546a0286fd03b822570d7a661dade28", kill_on_drop: false }`
[INFO] [stdout] 48e14dc2a607acab01b08ee7f42f39b9c546a0286fd03b822570d7a661dade28
[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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+b2f80f6008cdafc35b4472bd46afa16cc6b0cd63" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 15c4cb81f907108cf3328771747be6b47d3020a370e9b842e56583d681c07a17
[INFO] running `Command { std: "docker" "start" "-a" "15c4cb81f907108cf3328771747be6b47d3020a370e9b842e56583d681c07a17", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling libc v0.2.71
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]     Checking arrayvec v0.4.12
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[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 12.31s
[INFO] running `Command { std: "docker" "inspect" "15c4cb81f907108cf3328771747be6b47d3020a370e9b842e56583d681c07a17", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "15c4cb81f907108cf3328771747be6b47d3020a370e9b842e56583d681c07a17", kill_on_drop: false }`
[INFO] [stdout] 15c4cb81f907108cf3328771747be6b47d3020a370e9b842e56583d681c07a17