[INFO] cloning repository https://github.com/SDRust/png-fabuloso
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/SDRust/png-fabuloso" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSDRust%2Fpng-fabuloso", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSDRust%2Fpng-fabuloso'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ea682ace17550d1cbad67b1c27f35f6811a6a83d
[INFO] testing SDRust/png-fabuloso against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSDRust%2Fpng-fabuloso" "/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/SDRust/png-fabuloso 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/SDRust/png-fabuloso
[INFO] finished tweaking git repo https://github.com/SDRust/png-fabuloso
[INFO] tweaked toml for git repo https://github.com/SDRust/png-fabuloso written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/SDRust/png-fabuloso already has a lockfile, it will not be regenerated
[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] 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] ff4c7a046b7c5f3f2ffb06c33b5800c6ad8c190eed6b1ad192ab14affbb57830
[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" "ff4c7a046b7c5f3f2ffb06c33b5800c6ad8c190eed6b1ad192ab14affbb57830", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ff4c7a046b7c5f3f2ffb06c33b5800c6ad8c190eed6b1ad192ab14affbb57830", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ff4c7a046b7c5f3f2ffb06c33b5800c6ad8c190eed6b1ad192ab14affbb57830", kill_on_drop: false }`
[INFO] [stdout] ff4c7a046b7c5f3f2ffb06c33b5800c6ad8c190eed6b1ad192ab14affbb57830
[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] 1886873ad5d203daf27e02c8514ef92a3b5109fa42cad6a265ea937f29e2ffea
[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" "1886873ad5d203daf27e02c8514ef92a3b5109fa42cad6a265ea937f29e2ffea", kill_on_drop: false }`
[INFO] [stderr]    Compiling gcc v0.3.39
[INFO] [stderr]    Compiling crc v1.3.0
[INFO] [stderr]    Compiling miniz-sys v0.1.7
[INFO] [stderr]    Compiling flate2 v0.2.14
[INFO] [stderr]    Compiling pngstogram v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(type_ascription)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(slice_patterns)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `slice_patterns` has been stable since 1.42.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `pngstogram` due to 3 previous errors
[INFO] running `Command { std: "docker" "inspect" "1886873ad5d203daf27e02c8514ef92a3b5109fa42cad6a265ea937f29e2ffea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1886873ad5d203daf27e02c8514ef92a3b5109fa42cad6a265ea937f29e2ffea", kill_on_drop: false }`
[INFO] [stdout] 1886873ad5d203daf27e02c8514ef92a3b5109fa42cad6a265ea937f29e2ffea