[INFO] fetching crate monotonic_solver 0.5.0...
[INFO] testing monotonic_solver-0.5.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate monotonic_solver 0.5.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate monotonic_solver 0.5.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate monotonic_solver 0.5.0
[INFO] finished tweaking crates.io crate monotonic_solver 0.5.0
[INFO] tweaked toml for crates.io crate monotonic_solver 0.5.0 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate crates.io crate monotonic_solver 0.5.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7c8faf792979756ae71261a4238a335deeabd488a8afe01cd7de4be5790d6319
[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" "7c8faf792979756ae71261a4238a335deeabd488a8afe01cd7de4be5790d6319", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7c8faf792979756ae71261a4238a335deeabd488a8afe01cd7de4be5790d6319", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7c8faf792979756ae71261a4238a335deeabd488a8afe01cd7de4be5790d6319", kill_on_drop: false }`
[INFO] [stdout] 7c8faf792979756ae71261a4238a335deeabd488a8afe01cd7de4be5790d6319
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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=warn" "-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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] da96e98058d1a9bfc555df7e4d6c8b502225cbf7eed5fc0382789d26923ae0cc
[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" "da96e98058d1a9bfc555df7e4d6c8b502225cbf7eed5fc0382789d26923ae0cc", kill_on_drop: false }`
[INFO] [stderr]    Compiling monotonic_solver v0.5.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.64s
[INFO] running `Command { std: "docker" "inspect" "da96e98058d1a9bfc555df7e4d6c8b502225cbf7eed5fc0382789d26923ae0cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "da96e98058d1a9bfc555df7e4d6c8b502225cbf7eed5fc0382789d26923ae0cc", kill_on_drop: false }`
[INFO] [stdout] da96e98058d1a9bfc555df7e4d6c8b502225cbf7eed5fc0382789d26923ae0cc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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=warn" "-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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 20e0ec3e12922efbcbb6465989c846703242d138b85fb6e986a8dcc26d079f0f
[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" "20e0ec3e12922efbcbb6465989c846703242d138b85fb6e986a8dcc26d079f0f", kill_on_drop: false }`
[INFO] [stderr]    Compiling monotonic_solver v0.5.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> examples/drama.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(box_patterns)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `monotonic_solver`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "20e0ec3e12922efbcbb6465989c846703242d138b85fb6e986a8dcc26d079f0f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "20e0ec3e12922efbcbb6465989c846703242d138b85fb6e986a8dcc26d079f0f", kill_on_drop: false }`
[INFO] [stdout] 20e0ec3e12922efbcbb6465989c846703242d138b85fb6e986a8dcc26d079f0f