[INFO] fetching crate cex 0.5.0...
[INFO] checking cex-0.5.0 against beta for pr-78714
[INFO] extracting crate cex 0.5.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate cex 0.5.0 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 cex 0.5.0
[INFO] finished tweaking crates.io crate cex 0.5.0
[INFO] tweaked toml for crates.io crate cex 0.5.0 written to /workspace/builds/worker-3/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c25d40bd68efc04db939ac1c8eb772a45f92a62d23a21faf165390496f05d05e
[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" "c25d40bd68efc04db939ac1c8eb772a45f92a62d23a21faf165390496f05d05e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c25d40bd68efc04db939ac1c8eb772a45f92a62d23a21faf165390496f05d05e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c25d40bd68efc04db939ac1c8eb772a45f92a62d23a21faf165390496f05d05e", kill_on_drop: false }`
[INFO] [stdout] c25d40bd68efc04db939ac1c8eb772a45f92a62d23a21faf165390496f05d05e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bc859fdb676454eb432e30bf16d9be976551e22221d29424ce106d20be261806
[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" "bc859fdb676454eb432e30bf16d9be976551e22221d29424ce106d20be261806", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling hashbrown v0.9.1
[INFO] [stderr]    Compiling indexmap v1.6.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling syn v1.0.48
[INFO] [stderr]    Compiling enumx_derive v0.4.0
[INFO] [stderr]    Compiling cex_derive v0.5.0
[INFO] [stderr]     Checking enumx v0.4.1
[INFO] [stderr]     Checking cex v0.5.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> tests/syntax.rs:1:20
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![cfg_attr( test, feature( proc_macro_hygiene, stmt_expr_attributes, try_blocks ))]
[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 `cex`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "bc859fdb676454eb432e30bf16d9be976551e22221d29424ce106d20be261806", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bc859fdb676454eb432e30bf16d9be976551e22221d29424ce106d20be261806", kill_on_drop: false }`
[INFO] [stdout] bc859fdb676454eb432e30bf16d9be976551e22221d29424ce106d20be261806