[INFO] cloning repository https://github.com/kylewlacy/rust-conflicting-impl-specialization
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kylewlacy/rust-conflicting-impl-specialization" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkylewlacy%2Frust-conflicting-impl-specialization", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkylewlacy%2Frust-conflicting-impl-specialization'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e31c1e5305bc801850b7266e8817cda75342a948
[INFO] testing kylewlacy/rust-conflicting-impl-specialization against beta-2021-09-08 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fkylewlacy%2Frust-conflicting-impl-specialization" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/kylewlacy/rust-conflicting-impl-specialization on toolchain beta-2021-09-08
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/kylewlacy/rust-conflicting-impl-specialization
[INFO] finished tweaking git repo https://github.com/kylewlacy/rust-conflicting-impl-specialization
[INFO] tweaked toml for git repo https://github.com/kylewlacy/rust-conflicting-impl-specialization written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/kylewlacy/rust-conflicting-impl-specialization already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-09-08" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] abd6fa096aef0eed30646e0c305e3f36b37711c31c8cd84331858aaf85137752
[INFO] running `Command { std: "docker" "start" "-a" "abd6fa096aef0eed30646e0c305e3f36b37711c31c8cd84331858aaf85137752", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "abd6fa096aef0eed30646e0c305e3f36b37711c31c8cd84331858aaf85137752", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "abd6fa096aef0eed30646e0c305e3f36b37711c31c8cd84331858aaf85137752", kill_on_drop: false }`
[INFO] [stdout] abd6fa096aef0eed30646e0c305e3f36b37711c31c8cd84331858aaf85137752
[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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e8855b3a0436039276aad1615c26cd30a174dd048eed4660e680c82c2befd621
[INFO] running `Command { std: "docker" "start" "-a" "e8855b3a0436039276aad1615c26cd30a174dd048eed4660e680c82c2befd621", kill_on_drop: false }`
[INFO] [stderr]    Compiling child v0.1.0 (/opt/rustwide/workdir/child)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> child/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(specialization)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> child/src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(specialization)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]   = help: consider using `min_specialization` instead, which is more stable and complete
[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 `child` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "e8855b3a0436039276aad1615c26cd30a174dd048eed4660e680c82c2befd621", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e8855b3a0436039276aad1615c26cd30a174dd048eed4660e680c82c2befd621", kill_on_drop: false }`
[INFO] [stdout] e8855b3a0436039276aad1615c26cd30a174dd048eed4660e680c82c2befd621