[INFO] updating cached repository https://github.com/hnkz/runtime_experiment
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] d7c53f1011264ecc92fb890b2e228291a8381563
[INFO] checking hnkz/runtime_experiment against try#8810c24b0958114d8dbb32d878444e8956fce80f for pr-66063
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhnkz%2Fruntime_experiment" "/workspace/builds/worker-11/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/hnkz/runtime_experiment on toolchain 8810c24b0958114d8dbb32d878444e8956fce80f
[INFO] running `"/workspace/cargo-home/bin/cargo" "+8810c24b0958114d8dbb32d878444e8956fce80f" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/hnkz/runtime_experiment
[INFO] finished tweaking git repo https://github.com/hnkz/runtime_experiment
[INFO] tweaked toml for git repo https://github.com/hnkz/runtime_experiment written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/hnkz/runtime_experiment already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+8810c24b0958114d8dbb32d878444e8956fce80f" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=allow" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+8810c24b0958114d8dbb32d878444e8956fce80f" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] c42a00cd18e5a3b19825220b598aa43262cfa4a031ff26960c1d045f4e312e6b
[INFO] running `"docker" "start" "-a" "c42a00cd18e5a3b19825220b598aa43262cfa4a031ff26960c1d045f4e312e6b"`
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking async-datagram v2.2.0
[INFO] [stderr]    Compiling rand_chacha v0.2.0
[INFO] [stderr]     Checking getrandom v0.1.6
[INFO] [stderr]     Checking crossbeam-channel v0.3.8
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking backtrace-sys v0.1.30
[INFO] [stderr]     Checking crossbeam-deque v0.6.3
[INFO] [stderr]     Checking backtrace v0.3.32
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/async-datagram-2.2.0/src/lib.rs:43:1
[INFO] [stderr]    |
[INFO] [stderr] 43 | #![feature(futures_api)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `async-datagram`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "c42a00cd18e5a3b19825220b598aa43262cfa4a031ff26960c1d045f4e312e6b"`
[INFO] running `"docker" "rm" "-f" "c42a00cd18e5a3b19825220b598aa43262cfa4a031ff26960c1d045f4e312e6b"`
[INFO] [stdout] c42a00cd18e5a3b19825220b598aa43262cfa4a031ff26960c1d045f4e312e6b