[INFO] cloning repository https://github.com/shubhxms/nocap [INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/shubhxms/nocap" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap", kill_on_drop: false }` [INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap'... [INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }` [INFO] [stdout] c1a42c8f86ad96e82267b7699c84dccc19a056c6 [INFO] checking shubhxms/nocap against master#8387315ab3c26a57a1f53a90f188f0bc88514bca for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain 8387315ab3c26a57a1f53a90f188f0bc88514bca [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+8387315ab3c26a57a1f53a90f188f0bc88514bca" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc1/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+8387315ab3c26a57a1f53a90f188f0bc88514bca" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+8387315ab3c26a57a1f53a90f188f0bc88514bca" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 735e9263d4348710dab60995690a30532c458b1cc5dea07eea615de22fb47b74 [INFO] running `Command { std: "docker" "start" "-a" "735e9263d4348710dab60995690a30532c458b1cc5dea07eea615de22fb47b74", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "735e9263d4348710dab60995690a30532c458b1cc5dea07eea615de22fb47b74", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "735e9263d4348710dab60995690a30532c458b1cc5dea07eea615de22fb47b74", kill_on_drop: false }` [INFO] [stdout] 735e9263d4348710dab60995690a30532c458b1cc5dea07eea615de22fb47b74 [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+8387315ab3c26a57a1f53a90f188f0bc88514bca" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }` [INFO] [stdout] e6633f4ac3ad2058b32fa8fa99ba2321c8438fc64db55a5c3f61d14720c2765c [INFO] running `Command { std: "docker" "start" "-a" "e6633f4ac3ad2058b32fa8fa99ba2321c8438fc64db55a5c3f61d14720c2765c", kill_on_drop: false }` [INFO] [stderr] Compiling libc v0.2.139 [INFO] [stderr] Compiling getrandom v0.1.16 [INFO] [stderr] Checking cfg-if v1.0.0 [INFO] [stderr] Checking ppv-lite86 v0.2.17 [INFO] [stderr] Checking unicode-segmentation v1.10.0 [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 convert_case v0.6.0 [INFO] [stderr] Checking nocap v0.1.0 (/opt/rustwide/workdir) [INFO] [stderr] Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.17s [INFO] running `Command { std: "docker" "inspect" "e6633f4ac3ad2058b32fa8fa99ba2321c8438fc64db55a5c3f61d14720c2765c", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "e6633f4ac3ad2058b32fa8fa99ba2321c8438fc64db55a5c3f61d14720c2765c", kill_on_drop: false }` [INFO] [stdout] e6633f4ac3ad2058b32fa8fa99ba2321c8438fc64db55a5c3f61d14720c2765c [INFO] checking shubhxms/nocap against try#fcc50f77e1a14e407d895972348a0ff09eafc210 for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain fcc50f77e1a14e407d895972348a0ff09eafc210 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] dc7ffa92899dd45758be18f5517e6583fb0697907c4773d00c19da975b41c6e0 [INFO] running `Command { std: "docker" "start" "-a" "dc7ffa92899dd45758be18f5517e6583fb0697907c4773d00c19da975b41c6e0", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "dc7ffa92899dd45758be18f5517e6583fb0697907c4773d00c19da975b41c6e0", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "dc7ffa92899dd45758be18f5517e6583fb0697907c4773d00c19da975b41c6e0", kill_on_drop: false }` [INFO] [stdout] dc7ffa92899dd45758be18f5517e6583fb0697907c4773d00c19da975b41c6e0 [INFO] checking shubhxms/nocap against try#fcc50f77e1a14e407d895972348a0ff09eafc210 for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain fcc50f77e1a14e407d895972348a0ff09eafc210 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/120adf439c5df47b469a0ebb8726a719c9c38de5fb2e4c1a4f160846267620ec-init/merged/dev/shm: no space left on device [INFO] checking shubhxms/nocap against try#fcc50f77e1a14e407d895972348a0ff09eafc210 for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain fcc50f77e1a14e407d895972348a0ff09eafc210 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/57030f4ceda1af73db3f94f92f5bf171d796187eb7c68602998d7677cd51b0ff-init: no space left on device [INFO] checking shubhxms/nocap against try#fcc50f77e1a14e407d895972348a0ff09eafc210 for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain fcc50f77e1a14e407d895972348a0ff09eafc210 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/12fa360b85403fb7d7fa0dc940e4c009ed435e77c658194d3db22c4528d30ee7-init: no space left on device [INFO] checking shubhxms/nocap against try#fcc50f77e1a14e407d895972348a0ff09eafc210 for pr-124605 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshubhxms%2Fnocap" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/shubhxms/nocap on toolchain fcc50f77e1a14e407d895972348a0ff09eafc210 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/shubhxms/nocap [INFO] finished tweaking git repo https://github.com/shubhxms/nocap [INFO] tweaked toml for git repo https://github.com/shubhxms/nocap written to /workspace/builds/worker-1-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/shubhxms/nocap 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" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:59a85a07ab18ca8720692f8e61effa1c651d9e2ca591e072c2b212bb91a6b8b5" "/opt/rustwide/cargo-home/bin/cargo" "+fcc50f77e1a14e407d895972348a0ff09eafc210" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] f35843300810222777d943a1a8b9f4adf793784ad111c5932ca99dbeba959372 [INFO] running `Command { std: "docker" "start" "-a" "f35843300810222777d943a1a8b9f4adf793784ad111c5932ca99dbeba959372", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "f35843300810222777d943a1a8b9f4adf793784ad111c5932ca99dbeba959372", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "f35843300810222777d943a1a8b9f4adf793784ad111c5932ca99dbeba959372", kill_on_drop: false }` [INFO] [stdout] f35843300810222777d943a1a8b9f4adf793784ad111c5932ca99dbeba959372 [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.