[INFO] fetching crate gc_plugin 0.1.1...
[INFO] testing gc_plugin-0.1.1 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate gc_plugin 0.1.1 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate gc_plugin 0.1.1 on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate gc_plugin 0.1.1
[INFO] finished tweaking crates.io crate gc_plugin 0.1.1
[INFO] tweaked toml for crates.io crate gc_plugin 0.1.1 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 89d4523358a5132f1ffa876ca3ab61daf202a42b199479d345e5ca5c1a052ca1
[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" "89d4523358a5132f1ffa876ca3ab61daf202a42b199479d345e5ca5c1a052ca1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "89d4523358a5132f1ffa876ca3ab61daf202a42b199479d345e5ca5c1a052ca1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89d4523358a5132f1ffa876ca3ab61daf202a42b199479d345e5ca5c1a052ca1", kill_on_drop: false }`
[INFO] [stdout] 89d4523358a5132f1ffa876ca3ab61daf202a42b199479d345e5ca5c1a052ca1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--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] 590e8edfeb7735c2ddb6dca55073a5142d3e02c8569f3ccf599c9414c3606581
[INFO] running `Command { std: "docker" "start" "-a" "590e8edfeb7735c2ddb6dca55073a5142d3e02c8569f3ccf599c9414c3606581", kill_on_drop: false }`
[INFO] [stderr]    Compiling gc_plugin v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0463]: can't find crate for `syntax`
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | extern crate syntax;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^ can't find crate
[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 E0463`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `gc_plugin`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "590e8edfeb7735c2ddb6dca55073a5142d3e02c8569f3ccf599c9414c3606581", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "590e8edfeb7735c2ddb6dca55073a5142d3e02c8569f3ccf599c9414c3606581", kill_on_drop: false }`
[INFO] [stdout] 590e8edfeb7735c2ddb6dca55073a5142d3e02c8569f3ccf599c9414c3606581