[INFO] cloning repository https://github.com/post-rex/wasm-tests
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/post-rex/wasm-tests" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e7314091e2f08f9e4bedc982778eada4c1b0a65b
[INFO] checking post-rex/wasm-tests against master#e23ae72ac7a393961886ea62df065ebb6def7d51 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain e23ae72ac7a393961886ea62df065ebb6def7d51
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+e23ae72ac7a393961886ea62df065ebb6def7d51" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+e23ae72ac7a393961886ea62df065ebb6def7d51" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded wasmer v2.0.0
[INFO] [stderr]   Downloaded rkyv v0.6.7
[INFO] [stderr]   Downloaded inkwell_internals v0.3.0
[INFO] [stderr]   Downloaded wasmer-object v2.0.0
[INFO] [stderr]   Downloaded wasmer-engine v2.0.0
[INFO] [stderr]   Downloaded wasmer-engine-universal v2.0.0
[INFO] [stderr]   Downloaded wasmer-derive v2.0.0
[INFO] [stderr]   Downloaded wasmer-engine-dylib v2.0.0
[INFO] [stderr]   Downloaded llvm-sys v110.0.2
[INFO] [stderr]   Downloaded wasmer-compiler-llvm v2.0.0
[INFO] [stderr]   Downloaded wasmer_inkwell v0.2.0-alpha.2
[INFO] [stderr]   Downloaded wasmer-vm v2.0.0
[INFO] [stderr]   Downloaded wasmer-compiler v2.0.0
[INFO] [stderr]   Downloaded wasmer-types v2.0.0
[INFO] [stderr]   Downloaded rkyv_derive v0.6.7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+e23ae72ac7a393961886ea62df065ebb6def7d51" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 98e5d2f21e6ee3971a9642bad41b27daf44131145e2cac93f878e8aa04375eb3
[INFO] running `Command { std: "docker" "start" "-a" "98e5d2f21e6ee3971a9642bad41b27daf44131145e2cac93f878e8aa04375eb3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "98e5d2f21e6ee3971a9642bad41b27daf44131145e2cac93f878e8aa04375eb3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "98e5d2f21e6ee3971a9642bad41b27daf44131145e2cac93f878e8aa04375eb3", kill_on_drop: false }`
[INFO] [stdout] 98e5d2f21e6ee3971a9642bad41b27daf44131145e2cac93f878e8aa04375eb3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+e23ae72ac7a393961886ea62df065ebb6def7d51" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a
[INFO] running `Command { std: "docker" "start" "-a" "bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a", kill_on_drop: false }`
[INFO] [stderr] time="2024-06-19T18:52:06Z" level=error msg="error waiting for container: "
[INFO] [stderr] Error response from daemon: write /var/lib/docker/containers/bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a/hash1126903671: no space left on device
[INFO] running `Command { std: "docker" "inspect" "bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a", kill_on_drop: false }`
[INFO] [stdout] bb650021b1c61c396d3b16ece00c05ec0573641e202a7ecef0247f3d2234025a
[INFO] checking post-rex/wasm-tests against try#397f8958d101b259f6baaf92d107d770c95c3ce0 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain 397f8958d101b259f6baaf92d107d770c95c3ce0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: chown /var/lib/docker/overlay2/0b81d56ec8ae58da77454a36c599c531c855bb95ae817e5a32fa067323521847/work/work: no such file or directory
[INFO] checking post-rex/wasm-tests against try#397f8958d101b259f6baaf92d107d770c95c3ce0 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain 397f8958d101b259f6baaf92d107d770c95c3ce0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/988a61dabd8424c4a5784c661517402c51b93a156f9f6c37c5f07122d7afa7a1/merged: no space left on device
[INFO] checking post-rex/wasm-tests against try#397f8958d101b259f6baaf92d107d770c95c3ce0 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain 397f8958d101b259f6baaf92d107d770c95c3ce0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/containers/6eb36bcd0e08b2aad42936b8afb4581ed73d2d85e4387b2e56cf131835cb123d/checkpoints: no space left on device
[INFO] checking post-rex/wasm-tests against try#397f8958d101b259f6baaf92d107d770c95c3ce0 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain 397f8958d101b259f6baaf92d107d770c95c3ce0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/containers/6c0951920453ff9838fae792fe2410a0d13b020d011a411d24d201938a368941: no space left on device
[INFO] checking post-rex/wasm-tests against try#397f8958d101b259f6baaf92d107d770c95c3ce0 for pr-126571
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpost-rex%2Fwasm-tests" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/post-rex/wasm-tests on toolchain 397f8958d101b259f6baaf92d107d770c95c3ce0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] finished tweaking git repo https://github.com/post-rex/wasm-tests
[INFO] tweaked toml for git repo https://github.com/post-rex/wasm-tests written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/post-rex/wasm-tests 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" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:dff56e7819e73ed36160586b3445e93eb0be776c16704aeeded9c3fb668b2384" "/opt/rustwide/cargo-home/bin/cargo" "+397f8958d101b259f6baaf92d107d770c95c3ce0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] Error response from daemon: write /var/lib/docker/image/overlay2/layerdb/mounts/e7e1cc48080cef6caab665cedb400000f90c87dc2d7d268fc7cc0a08759c2722/parent: no space left on device
[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.