[INFO] fetching crate runtime-attributes 0.3.0-alpha.6...
[INFO] checking runtime-attributes-0.3.0-alpha.6 against try#3e22d1f9053c0fc87629b3c6d5d9567856368e5d for pr-78714
[INFO] extracting crate runtime-attributes 0.3.0-alpha.6 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate runtime-attributes 0.3.0-alpha.6 on toolchain 3e22d1f9053c0fc87629b3c6d5d9567856368e5d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate runtime-attributes 0.3.0-alpha.6
[INFO] finished tweaking crates.io crate runtime-attributes 0.3.0-alpha.6
[INFO] tweaked toml for crates.io crate runtime-attributes 0.3.0-alpha.6 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ddc9c84db21f5df07c1fd48a9f8119d9787092cd2e9909e5e86425751e6b49ef
[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" "ddc9c84db21f5df07c1fd48a9f8119d9787092cd2e9909e5e86425751e6b49ef", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ddc9c84db21f5df07c1fd48a9f8119d9787092cd2e9909e5e86425751e6b49ef", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ddc9c84db21f5df07c1fd48a9f8119d9787092cd2e9909e5e86425751e6b49ef", kill_on_drop: false }`
[INFO] [stdout] ddc9c84db21f5df07c1fd48a9f8119d9787092cd2e9909e5e86425751e6b49ef
[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=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" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bf3c8e3571afb17f0c499213687d4019dd8c2d7d669731e468cbbdb8c76d913b
[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" "bf3c8e3571afb17f0c499213687d4019dd8c2d7d669731e468cbbdb8c76d913b", kill_on_drop: false }`
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking quote v1.0.7
[INFO] [stderr]     Checking syn v1.0.48
[INFO] [stderr]     Checking futures-executor-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking runtime-attributes v0.3.0-alpha.6 (/opt/rustwide/workdir)
[INFO] [stdout] error: unused extern crate
[INFO] [stdout]  --> src/lib.rs:8:1
[INFO] [stdout]   |
[INFO] [stdout] 8 | extern crate proc_macro;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
[INFO] [stdout]   |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]  --> src/lib.rs:4:45
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![forbid(unsafe_code, future_incompatible, rust_2018_idioms)]
[INFO] [stdout]   |                                             ^^^^^^^^^^^^^^^^
[INFO] [stdout]   = note: `#[forbid(unused_extern_crates)]` implied by `#[forbid(rust_2018_idioms)]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `runtime-attributes`
[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" "bf3c8e3571afb17f0c499213687d4019dd8c2d7d669731e468cbbdb8c76d913b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bf3c8e3571afb17f0c499213687d4019dd8c2d7d669731e468cbbdb8c76d913b", kill_on_drop: false }`
[INFO] [stdout] bf3c8e3571afb17f0c499213687d4019dd8c2d7d669731e468cbbdb8c76d913b