[INFO] cloning repository https://github.com/nebula-technologies/singleton-manager
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nebula-technologies/singleton-manager" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnebula-technologies%2Fsingleton-manager", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnebula-technologies%2Fsingleton-manager'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5e233ee937d2ec3d5bc78a8a42f8f2890879eeb5
[INFO] testing nebula-technologies/singleton-manager against 1.90.0 for beta-1.91-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnebula-technologies%2Fsingleton-manager" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] removed /workspace/builds/worker-6-tc1/source/rust-toolchain
[INFO] started tweaking git repo https://github.com/nebula-technologies/singleton-manager
[INFO] finished tweaking git repo https://github.com/nebula-technologies/singleton-manager
[INFO] tweaked toml for git repo https://github.com/nebula-technologies/singleton-manager written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/nebula-technologies/singleton-manager on toolchain 1.90.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/nebula-technologies/singleton-manager already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: unused manifest key: dependencies.uuid.versio
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded libc v0.2.99
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8eb0c6ea849edfdbac69089753337dfc6e87fc4d594b5ebb7bfc49a2ffee0fc7
[INFO] running `Command { std: "docker" "start" "-a" "8eb0c6ea849edfdbac69089753337dfc6e87fc4d594b5ebb7bfc49a2ffee0fc7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8eb0c6ea849edfdbac69089753337dfc6e87fc4d594b5ebb7bfc49a2ffee0fc7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8eb0c6ea849edfdbac69089753337dfc6e87fc4d594b5ebb7bfc49a2ffee0fc7", kill_on_drop: false }`
[INFO] [stdout] 8eb0c6ea849edfdbac69089753337dfc6e87fc4d594b5ebb7bfc49a2ffee0fc7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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" "RUSTDOCFLAGS=--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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 05685f34b418bc1ec1fc3f4c6af34beea0e35132504f262ea7e1bbaf23658fdb
[INFO] running `Command { std: "docker" "start" "-a" "05685f34b418bc1ec1fc3f4c6af34beea0e35132504f262ea7e1bbaf23658fdb", kill_on_drop: false }`
[INFO] [stderr] warning: unused manifest key: dependencies.uuid.versio
[INFO] [stderr]    Compiling libc v0.2.99
[INFO] [stderr]    Compiling getrandom v0.2.3
[INFO] [stderr]    Compiling uuid v0.8.2
[INFO] [stderr]    Compiling singleton-manager v0.1.3 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(fn_traits)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `singleton-manager` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "05685f34b418bc1ec1fc3f4c6af34beea0e35132504f262ea7e1bbaf23658fdb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "05685f34b418bc1ec1fc3f4c6af34beea0e35132504f262ea7e1bbaf23658fdb", kill_on_drop: false }`
[INFO] [stdout] 05685f34b418bc1ec1fc3f4c6af34beea0e35132504f262ea7e1bbaf23658fdb