[INFO] fetching crate meio 0.23.0...
[INFO] checking meio-0.23.0 against beta for pr-78714
[INFO] extracting crate meio 0.23.0 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate meio 0.23.0 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate meio 0.23.0
[INFO] finished tweaking crates.io crate meio 0.23.0
[INFO] tweaked toml for crates.io crate meio 0.23.0 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", 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] 357261bb21ede015b095ad3c1f2b6485e02ce1462241b1430ad47b461098e00e
[INFO] running `Command { std: "docker" "start" "-a" "357261bb21ede015b095ad3c1f2b6485e02ce1462241b1430ad47b461098e00e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "357261bb21ede015b095ad3c1f2b6485e02ce1462241b1430ad47b461098e00e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "357261bb21ede015b095ad3c1f2b6485e02ce1462241b1430ad47b461098e00e", kill_on_drop: false }`
[INFO] [stdout] 357261bb21ede015b095ad3c1f2b6485e02ce1462241b1430ad47b461098e00e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1f9aa3480aab9bad95e4b12c1d179c41d405d2717ee4473f56455eb1c3a99311
[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" "1f9aa3480aab9bad95e4b12c1d179c41d405d2717ee4473f56455eb1c3a99311", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]    Compiling anyhow v1.0.34
[INFO] [stderr]     Checking regex-syntax v0.6.21
[INFO] [stderr]     Checking memchr v2.3.4
[INFO] [stderr]     Checking signal-hook-registry v1.2.2
[INFO] [stderr]     Checking getrandom v0.1.15
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking tracing v0.1.21
[INFO] [stderr]     Checking want v0.3.0
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking aho-corasick v0.7.15
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking uuid v0.8.1
[INFO] [stderr]     Checking regex v1.4.2
[INFO] [stderr]     Checking env_logger v0.7.1
[INFO] [stderr]    Compiling pin-project-internal v1.0.1
[INFO] [stderr]    Compiling futures-macro v0.3.8
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling pin-project-internal v0.4.27
[INFO] [stderr]    Compiling async-trait v0.1.41
[INFO] [stderr]    Compiling derive_more v0.99.11
[INFO] [stderr]     Checking tokio v0.2.23
[INFO] [stderr]     Checking pin-project v1.0.1
[INFO] [stderr]     Checking futures-util v0.3.8
[INFO] [stderr]     Checking pin-project v0.4.27
[INFO] [stderr]     Checking tracing-futures v0.2.4
[INFO] [stderr]     Checking tokio-util v0.3.1
[INFO] [stderr]     Checking futures-executor v0.3.8
[INFO] [stderr]     Checking h2 v0.2.7
[INFO] [stderr]     Checking futures v0.3.8
[INFO] [stderr]     Checking meio v0.23.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> src/lib.rs:13:1
[INFO] [stdout]    |
[INFO] [stdout] 13 | #![feature(generators)]
[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 `meio`
[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" "1f9aa3480aab9bad95e4b12c1d179c41d405d2717ee4473f56455eb1c3a99311", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1f9aa3480aab9bad95e4b12c1d179c41d405d2717ee4473f56455eb1c3a99311", kill_on_drop: false }`
[INFO] [stdout] 1f9aa3480aab9bad95e4b12c1d179c41d405d2717ee4473f56455eb1c3a99311