[INFO] fetching crate desk-exit-screen 0.2.1...
[INFO] testing desk-exit-screen-0.2.1 against 1.49.0 for beta-1.50-1
[INFO] extracting crate desk-exit-screen 0.2.1 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate desk-exit-screen 0.2.1 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 desk-exit-screen 0.2.1
[INFO] finished tweaking crates.io crate desk-exit-screen 0.2.1
[INFO] tweaked toml for crates.io crate desk-exit-screen 0.2.1 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate crates.io crate desk-exit-screen 0.2.1 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] b94edf2d61c4914b7d48d65619dc89ab4a5fdf70f30b892e6fd755f8b8787f3d
[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" "b94edf2d61c4914b7d48d65619dc89ab4a5fdf70f30b892e6fd755f8b8787f3d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b94edf2d61c4914b7d48d65619dc89ab4a5fdf70f30b892e6fd755f8b8787f3d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b94edf2d61c4914b7d48d65619dc89ab4a5fdf70f30b892e6fd755f8b8787f3d", kill_on_drop: false }`
[INFO] [stdout] b94edf2d61c4914b7d48d65619dc89ab4a5fdf70f30b892e6fd755f8b8787f3d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] 9f6821f32970e7b2a73a0dcf65a2cda72b8bbcd751f95910d0460342c6f8a694
[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" "9f6821f32970e7b2a73a0dcf65a2cda72b8bbcd751f95910d0460342c6f8a694", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.35
[INFO] [stderr]    Compiling pkg-config v0.3.18
[INFO] [stderr]    Compiling strum v0.18.0
[INFO] [stderr]    Compiling version-compare v0.0.10
[INFO] [stderr]    Compiling libc v0.2.73
[INFO] [stderr]    Compiling futures-sink v0.3.5
[INFO] [stderr]    Compiling once_cell v1.4.0
[INFO] [stderr]    Compiling anyhow v1.0.32
[INFO] [stderr]    Compiling futures-io v0.3.5
[INFO] [stderr]    Compiling gio v0.9.0
[INFO] [stderr]    Compiling pango v0.9.0
[INFO] [stderr]    Compiling gdk v0.13.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling futures-channel v0.3.5
[INFO] [stderr]    Compiling futures-task v0.3.5
[INFO] [stderr]    Compiling libdbus-sys v0.2.1
[INFO] [stderr]    Compiling gtk v0.9.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling dbus v0.8.4
[INFO] [stderr]    Compiling nix v0.17.0
[INFO] [stderr]    Compiling dirs-sys v0.3.5
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling env_logger v0.7.1
[INFO] [stderr]    Compiling directories v3.0.1
[INFO] [stderr]    Compiling syn-mid v0.5.0
[INFO] [stderr]    Compiling serde_derive v1.0.114
[INFO] [stderr]    Compiling thiserror-impl v1.0.20
[INFO] [stderr]    Compiling strum_macros v0.18.0
[INFO] [stderr]    Compiling pin-project-internal v0.4.22
[INFO] [stderr]    Compiling futures-macro v0.3.5
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.3
[INFO] [stderr]    Compiling proc-macro-error v1.0.3
[INFO] [stderr]    Compiling thiserror v1.0.20
[INFO] [stderr]    Compiling desk-logind v1.1.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/desk-logind-1.1.0/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(backtrace)]
[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 `desk-logind`
[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" "9f6821f32970e7b2a73a0dcf65a2cda72b8bbcd751f95910d0460342c6f8a694", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9f6821f32970e7b2a73a0dcf65a2cda72b8bbcd751f95910d0460342c6f8a694", kill_on_drop: false }`
[INFO] [stdout] 9f6821f32970e7b2a73a0dcf65a2cda72b8bbcd751f95910d0460342c6f8a694