[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] checking mahkoh/trait-union against 1.55.0 for beta-1.56-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmahkoh%2Ftrait-union" "/workspace/builds/worker-42/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-42/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-42/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded trybuild v1.0.50
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-42/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-42/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] 7c8f5d94bf16d0713382c9c64b4c9cfef65e8ef13a73207ecc65915f00fb201c
[INFO] running `Command { std: "docker" "start" "-a" "7c8f5d94bf16d0713382c9c64b4c9cfef65e8ef13a73207ecc65915f00fb201c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7c8f5d94bf16d0713382c9c64b4c9cfef65e8ef13a73207ecc65915f00fb201c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7c8f5d94bf16d0713382c9c64b4c9cfef65e8ef13a73207ecc65915f00fb201c", kill_on_drop: false }`
[INFO] [stdout] 7c8f5d94bf16d0713382c9c64b4c9cfef65e8ef13a73207ecc65915f00fb201c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-42/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-42/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" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0c10c61e4b30dfb58cbf7b618be462cdcee1820c1035d053073b118fa3033802
[INFO] running `Command { std: "docker" "start" "-a" "0c10c61e4b30dfb58cbf7b618be462cdcee1820c1035d053073b118fa3033802", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.30
[INFO] [stderr]    Compiling syn v1.0.80
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling serde_json v1.0.68
[INFO] [stderr]    Compiling trybuild v1.0.50
[INFO] [stderr]     Checking itoa v0.4.8
[INFO] [stderr]     Checking termcolor v1.1.2
[INFO] [stderr]     Checking glob v0.3.0
[INFO] [stderr]    Compiling quote v1.0.10
[INFO] [stderr]     Checking trait-union-proc v0.1.4 (/opt/rustwide/workdir/proc)
[INFO] [stderr]     Checking trait-union v0.1.4 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking toml v0.5.8
[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" "0c10c61e4b30dfb58cbf7b618be462cdcee1820c1035d053073b118fa3033802", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c10c61e4b30dfb58cbf7b618be462cdcee1820c1035d053073b118fa3033802", kill_on_drop: false }`
[INFO] [stdout] 0c10c61e4b30dfb58cbf7b618be462cdcee1820c1035d053073b118fa3033802
