[INFO] fetching crate context-attribute 1.0.0...
[INFO] testing context-attribute-1.0.0 against master#a77da2d454e6caa227a85b16410b95f93495e7e0 for pr-91031
[INFO] extracting crate context-attribute 1.0.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate context-attribute 1.0.0 on toolchain a77da2d454e6caa227a85b16410b95f93495e7e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate context-attribute 1.0.0
[INFO] finished tweaking crates.io crate context-attribute 1.0.0
[INFO] tweaked toml for crates.io crate context-attribute 1.0.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "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] f96568e3849976eae8c0e1cce9da7927b3ce956a5b63d18ffd240963904970f1
[INFO] running `Command { std: "docker" "start" "-a" "f96568e3849976eae8c0e1cce9da7927b3ce956a5b63d18ffd240963904970f1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f96568e3849976eae8c0e1cce9da7927b3ce956a5b63d18ffd240963904970f1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f96568e3849976eae8c0e1cce9da7927b3ce956a5b63d18ffd240963904970f1", kill_on_drop: false }`
[INFO] [stdout] f96568e3849976eae8c0e1cce9da7927b3ce956a5b63d18ffd240963904970f1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+a77da2d454e6caa227a85b16410b95f93495e7e0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d1d8e1e041f72534d712b8ee5b77b2f1b24c6fcdf79c592557178cde229bf299
[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" "d1d8e1e041f72534d712b8ee5b77b2f1b24c6fcdf79c592557178cde229bf299", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling syn v1.0.81
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling gimli v0.26.1
[INFO] [stderr]    Compiling adler v1.0.2
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling rustc-demangle v0.1.21
[INFO] [stderr]    Compiling miniz_oxide v0.4.4
[INFO] [stderr]    Compiling backtrace v0.3.63
[INFO] [stderr]    Compiling object v0.27.1
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling addr2line v0.17.0
[INFO] [stderr]    Compiling synstructure v0.12.6
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling context-attribute v1.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: unused extern crate
[INFO] [stdout]   --> src/lib.rs:45:1
[INFO] [stdout]    |
[INFO] [stdout] 45 | 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:39:45
[INFO] [stdout]    |
[INFO] [stdout] 39 | #![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 `context-attribute` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "d1d8e1e041f72534d712b8ee5b77b2f1b24c6fcdf79c592557178cde229bf299", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d1d8e1e041f72534d712b8ee5b77b2f1b24c6fcdf79c592557178cde229bf299", kill_on_drop: false }`
[INFO] [stdout] d1d8e1e041f72534d712b8ee5b77b2f1b24c6fcdf79c592557178cde229bf299