[INFO] fetching crate mason 0.0.0...
[INFO] checking mason-0.0.0 against beta for pr-78714
[INFO] extracting crate mason 0.0.0 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate mason 0.0.0 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 mason 0.0.0
[INFO] finished tweaking crates.io crate mason 0.0.0
[INFO] tweaked toml for crates.io crate mason 0.0.0 written to /workspace/builds/worker-6/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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 1377f03c480d891c5d4d3c13bc6571930fc32593ff314099a96cd066e2c21a91
[INFO] running `Command { std: "docker" "start" "-a" "1377f03c480d891c5d4d3c13bc6571930fc32593ff314099a96cd066e2c21a91", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1377f03c480d891c5d4d3c13bc6571930fc32593ff314099a96cd066e2c21a91", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1377f03c480d891c5d4d3c13bc6571930fc32593ff314099a96cd066e2c21a91", kill_on_drop: false }`
[INFO] [stdout] 1377f03c480d891c5d4d3c13bc6571930fc32593ff314099a96cd066e2c21a91
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 5361fc1ee619d9f4b161c47e7cf66f9774fe424edc4be3f356a140784b786825
[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" "5361fc1ee619d9f4b161c47e7cf66f9774fe424edc4be3f356a140784b786825", kill_on_drop: false }`
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]     Checking async-ready v3.0.0
[INFO] [stderr]     Checking async-datagram v3.0.0
[INFO] [stderr]     Checking crossbeam-utils v0.6.6
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]     Checking futures-executor-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-timer v0.3.0
[INFO] [stderr]     Checking runtime-raw v0.3.0-alpha.5
[INFO] [stderr]     Checking romio v0.3.0-alpha.10
[INFO] [stderr]     Checking juliex v0.3.0-alpha.8
[INFO] [stderr]     Checking runtime-native v0.3.0-alpha.6
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling runtime-attributes v0.3.0-alpha.6
[INFO] [stderr]     Checking runtime v0.3.0-alpha.4
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/runtime-0.3.0-alpha.4/src/lib.rs:88:1
[INFO] [stdout]    |
[INFO] [stdout] 88 | #![feature(async_await)]
[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 `runtime`
[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" "5361fc1ee619d9f4b161c47e7cf66f9774fe424edc4be3f356a140784b786825", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5361fc1ee619d9f4b161c47e7cf66f9774fe424edc4be3f356a140784b786825", kill_on_drop: false }`
[INFO] [stdout] 5361fc1ee619d9f4b161c47e7cf66f9774fe424edc4be3f356a140784b786825