[INFO] cloning repository https://github.com/stefanSchinkel/rustylights
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/stefanSchinkel/rustylights" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights'...
[INFO] [stderr] /workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights: No space left on device
[WARN] Retrying crate fetch in 3 seconds (attempt 1)
[INFO] cloning repository https://github.com/stefanSchinkel/rustylights
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/stefanSchinkel/rustylights" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] fb198e3bf905f36ad1f019eaa7eabb7eaab3422c
[INFO] testing stefanSchinkel/rustylights against master#1ddedbaa5919b7b3e70d984660e21e844c615c97 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 1ddedbaa5919b7b3e70d984660e21e844c615c97
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1ddedbaa5919b7b3e70d984660e21e844c615c97" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+1ddedbaa5919b7b3e70d984660e21e844c615c97" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1ddedbaa5919b7b3e70d984660e21e844c615c97" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f4b74fa1ba2b0d275f51f2dd1d7997586728eaf4ece0d455c0aba0d629e1aa3a
[INFO] running `Command { std: "docker" "start" "-a" "f4b74fa1ba2b0d275f51f2dd1d7997586728eaf4ece0d455c0aba0d629e1aa3a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f4b74fa1ba2b0d275f51f2dd1d7997586728eaf4ece0d455c0aba0d629e1aa3a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f4b74fa1ba2b0d275f51f2dd1d7997586728eaf4ece0d455c0aba0d629e1aa3a", kill_on_drop: false }`
[INFO] [stdout] f4b74fa1ba2b0d275f51f2dd1d7997586728eaf4ece0d455c0aba0d629e1aa3a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1ddedbaa5919b7b3e70d984660e21e844c615c97" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 51641b57a0073fd2c9a1057e4d2f753101f7f99c1022fd1f15749448b179a31a
[INFO] running `Command { std: "docker" "start" "-a" "51641b57a0073fd2c9a1057e4d2f753101f7f99c1022fd1f15749448b179a31a", kill_on_drop: false }`
[INFO] [stderr] error: failed to create directory `/opt/rustwide/target/debug/.fingerprint/binascii-808e92deeb271ee8`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   No space left on device (os error 28)
[INFO] running `Command { std: "docker" "inspect" "51641b57a0073fd2c9a1057e4d2f753101f7f99c1022fd1f15749448b179a31a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "51641b57a0073fd2c9a1057e4d2f753101f7f99c1022fd1f15749448b179a31a", kill_on_drop: false }`
[INFO] [stdout] 51641b57a0073fd2c9a1057e4d2f753101f7f99c1022fd1f15749448b179a31a
[INFO] testing stefanSchinkel/rustylights against try#33f1d8bb92813a1bfc23c093c9f443ab09290307 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 33f1d8bb92813a1bfc23c093c9f443ab09290307
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: write /var/lib/docker/containers/a4600ded938a7e7c7a7e94892eaf82becf6a50dd5d1278711bcf7b758e0d87bd/.tmp-hostconfig.json160753788: no space left on device
[INFO] testing stefanSchinkel/rustylights against try#33f1d8bb92813a1bfc23c093c9f443ab09290307 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 33f1d8bb92813a1bfc23c093c9f443ab09290307
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/255190ca82eb6760e9b0114e0a512678ad6d93900151a0ab7a506b0eeb7b5149/merged/opt/rustwide/workdir: no space left on device
[INFO] testing stefanSchinkel/rustylights against try#33f1d8bb92813a1bfc23c093c9f443ab09290307 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 33f1d8bb92813a1bfc23c093c9f443ab09290307
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/606c86f5c496ac4dfea77ef4236228e76828beaacd43436fef82b4be900ebd0b/merged/opt/rustwide: no space left on device
[INFO] testing stefanSchinkel/rustylights against try#33f1d8bb92813a1bfc23c093c9f443ab09290307 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 33f1d8bb92813a1bfc23c093c9f443ab09290307
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/cdea263a82c62c1d46b61127b5ddb34ab2374ba6484bd67187d6c2a721bd7b0d/merged/opt/rustwide: no space left on device
[INFO] testing stefanSchinkel/rustylights against try#33f1d8bb92813a1bfc23c093c9f443ab09290307 for pr-128400
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FstefanSchinkel%2Frustylights" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/stefanSchinkel/rustylights on toolchain 33f1d8bb92813a1bfc23c093c9f443ab09290307
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] finished tweaking git repo https://github.com/stefanSchinkel/rustylights
[INFO] tweaked toml for git repo https://github.com/stefanSchinkel/rustylights written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/stefanSchinkel/rustylights 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" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+33f1d8bb92813a1bfc23c093c9f443ab09290307" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: chown /var/lib/docker/overlay2/c8686e43d4a41d85009b165b3275165baf72c8195205d9737b94a715284d2696/work/work: no such file or directory
[ERROR] this task or one of its parent failed!
[ERROR] command failed: exit status: 1
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.