[INFO] cloning repository https://github.com/PvdBerg1998/futures-executor
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/PvdBerg1998/futures-executor" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FPvdBerg1998%2Ffutures-executor", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FPvdBerg1998%2Ffutures-executor'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1c8ac9c99af48a0cff0cfc399f2943858863eafa
[INFO] testing PvdBerg1998/futures-executor against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FPvdBerg1998%2Ffutures-executor" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/PvdBerg1998/futures-executor 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 git repo https://github.com/PvdBerg1998/futures-executor
[INFO] finished tweaking git repo https://github.com/PvdBerg1998/futures-executor
[INFO] tweaked toml for git repo https://github.com/PvdBerg1998/futures-executor written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/PvdBerg1998/futures-executor 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-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] 511fb1b71e3dade1f21903adc6eda1da5e68c3c27a32830e55c9e14046ae898a
[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" "511fb1b71e3dade1f21903adc6eda1da5e68c3c27a32830e55c9e14046ae898a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "511fb1b71e3dade1f21903adc6eda1da5e68c3c27a32830e55c9e14046ae898a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "511fb1b71e3dade1f21903adc6eda1da5e68c3c27a32830e55c9e14046ae898a", kill_on_drop: false }`
[INFO] [stdout] 511fb1b71e3dade1f21903adc6eda1da5e68c3c27a32830e55c9e14046ae898a
[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] 60e9131700e0afa907255980ae46af6d8e41cecd7aa938ce8296ed1bd3890bce
[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" "60e9131700e0afa907255980ae46af6d8e41cecd7aa938ce8296ed1bd3890bce", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.55
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling slotmap v0.4.0
[INFO] [stderr]    Compiling crossbeam-utils v0.6.5
[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/slotmap-0.4.0/src/lib.rs:4:35
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "unstable", feature(untagged_unions, try_reserve))]
[INFO] [stdout]   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[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 `slotmap`
[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" "60e9131700e0afa907255980ae46af6d8e41cecd7aa938ce8296ed1bd3890bce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "60e9131700e0afa907255980ae46af6d8e41cecd7aa938ce8296ed1bd3890bce", kill_on_drop: false }`
[INFO] [stdout] 60e9131700e0afa907255980ae46af6d8e41cecd7aa938ce8296ed1bd3890bce