[INFO] cloning repository https://github.com/mahkoh/trait-union
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mahkoh/trait-union" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmahkoh%2Ftrait-union", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmahkoh%2Ftrait-union'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 033926a33ffa5010e40b83e924c9f346f5576c30
[INFO] testing mahkoh/trait-union against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmahkoh%2Ftrait-union" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mahkoh/trait-union on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mahkoh/trait-union
[INFO] finished tweaking git repo https://github.com/mahkoh/trait-union
[INFO] tweaked toml for git repo https://github.com/mahkoh/trait-union written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9fc66dbfcee3d3c9f4ece825aba93eec5f94741463378213c805bc45ffd6e5ba
[INFO] running `Command { std: "docker" "start" "-a" "9fc66dbfcee3d3c9f4ece825aba93eec5f94741463378213c805bc45ffd6e5ba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9fc66dbfcee3d3c9f4ece825aba93eec5f94741463378213c805bc45ffd6e5ba", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9fc66dbfcee3d3c9f4ece825aba93eec5f94741463378213c805bc45ffd6e5ba", kill_on_drop: false }`
[INFO] [stdout] 9fc66dbfcee3d3c9f4ece825aba93eec5f94741463378213c805bc45ffd6e5ba
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3223f5450d3cc4aec663d509920cc8a9112331e358e96bf4a7cbf87af7c353a7
[INFO] running `Command { std: "docker" "start" "-a" "3223f5450d3cc4aec663d509920cc8a9112331e358e96bf4a7cbf87af7c353a7", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling trait-union-proc v0.1.4 (/opt/rustwide/workdir/proc)
[INFO] [stderr]    Compiling trait-union v0.1.4 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 11.99s
[INFO] running `Command { std: "docker" "inspect" "3223f5450d3cc4aec663d509920cc8a9112331e358e96bf4a7cbf87af7c353a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3223f5450d3cc4aec663d509920cc8a9112331e358e96bf4a7cbf87af7c353a7", kill_on_drop: false }`
[INFO] [stdout] 3223f5450d3cc4aec663d509920cc8a9112331e358e96bf4a7cbf87af7c353a7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+1.55.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 94cec11cb6bc43cce5534a2323ef4848323f2d2bf7eff1ef73a00a14052bce60
[INFO] running `Command { std: "docker" "start" "-a" "94cec11cb6bc43cce5534a2323ef4848323f2d2bf7eff1ef73a00a14052bce60", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling serde_json v1.0.67
[INFO] [stderr]    Compiling itoa v0.4.8
[INFO] [stderr]    Compiling trybuild v1.0.45
[INFO] [stderr]    Compiling toml v0.5.8
[INFO] [stderr]    Compiling trait-union v0.1.4 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(test, feature(untagged_unions))]
[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 `trait-union` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "94cec11cb6bc43cce5534a2323ef4848323f2d2bf7eff1ef73a00a14052bce60", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "94cec11cb6bc43cce5534a2323ef4848323f2d2bf7eff1ef73a00a14052bce60", kill_on_drop: false }`
[INFO] [stdout] 94cec11cb6bc43cce5534a2323ef4848323f2d2bf7eff1ef73a00a14052bce60