[INFO] updating cached repository https://github.com/anderejd/extern_attrib
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a70c0caf5ddb993cde6e65d89b125f168e1d5dcc
[INFO] testing anderejd/extern_attrib against 1.45.2 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fanderejd%2Fextern_attrib" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/anderejd/extern_attrib on toolchain 1.45.2
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.45.2" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/anderejd/extern_attrib
[INFO] finished tweaking git repo https://github.com/anderejd/extern_attrib
[INFO] tweaked toml for git repo https://github.com/anderejd/extern_attrib written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/anderejd/extern_attrib already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.45.2" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] error: the lock file /workspace/builds/worker-7/source/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] [stderr] If you want to try to generate the lock file without accessing the network, use the --offline flag.
[INFO] the lockfile is outdated, regenerating it
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.45.2" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.45.2" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8028aa4273274298edacf943fad3148808dc02b36edd96bcc145ebfede8eba20
[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" "8028aa4273274298edacf943fad3148808dc02b36edd96bcc145ebfede8eba20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8028aa4273274298edacf943fad3148808dc02b36edd96bcc145ebfede8eba20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8028aa4273274298edacf943fad3148808dc02b36edd96bcc145ebfede8eba20", kill_on_drop: false }`
[INFO] [stdout] 8028aa4273274298edacf943fad3148808dc02b36edd96bcc145ebfede8eba20
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+1.45.2" "build" "--frozen" "--message-format=json", 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] 47ad5a7a7f00a22e02bc057eba8b4e0d08b1209639eeaac58af23ab219330c9c
[INFO] running `Command { std: "docker" "start" "-a" "47ad5a7a7f00a22e02bc057eba8b4e0d08b1209639eeaac58af23ab219330c9c", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v0.11.11
[INFO] [stderr]    Compiling extern_attrib v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:13:1
[INFO] [stdout]    |
[INFO] [stdout] 13 | #![feature(proc_macro)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/lib.rs:35:7
[INFO] [stdout]    |
[INFO] [stdout] 35 |       { //! This scope drops abi_opt after mutation.
[INFO] [stdout]    |  _____- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 36 | |         let abi_opt = match item.node {
[INFO] [stdout] 37 | |             ItemKind::Fn(_, _, _, ref mut opt, _, _) => opt,
[INFO] [stdout] 38 | |             _ => return input
[INFO] [stdout] 39 | |         };
[INFO] [stdout] 40 | |         modify_abi(abi_opt);
[INFO] [stdout] 41 | |     }
[INFO] [stdout]    | |_____- rustdoc does not generate documentation for expressions
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `extern_attrib`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "47ad5a7a7f00a22e02bc057eba8b4e0d08b1209639eeaac58af23ab219330c9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "47ad5a7a7f00a22e02bc057eba8b4e0d08b1209639eeaac58af23ab219330c9c", kill_on_drop: false }`
[INFO] [stdout] 47ad5a7a7f00a22e02bc057eba8b4e0d08b1209639eeaac58af23ab219330c9c