[INFO] fetching crate components-arena 2.1.5...
[INFO] testing components-arena-2.1.5 against 1.55.0 for beta-1.56-1
[INFO] extracting crate components-arena 2.1.5 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate components-arena 2.1.5 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 crates.io crate components-arena 2.1.5
[INFO] finished tweaking crates.io crate components-arena 2.1.5
[INFO] tweaked toml for crates.io crate components-arena 2.1.5 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate components-arena 2.1.5 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-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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] 6c9212c73d644147ada3adddd651fd62e919ffdaadc56c3095497dda216d79f0
[INFO] running `Command { std: "docker" "start" "-a" "6c9212c73d644147ada3adddd651fd62e919ffdaadc56c3095497dda216d79f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6c9212c73d644147ada3adddd651fd62e919ffdaadc56c3095497dda216d79f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6c9212c73d644147ada3adddd651fd62e919ffdaadc56c3095497dda216d79f0", kill_on_drop: false }`
[INFO] [stdout] 6c9212c73d644147ada3adddd651fd62e919ffdaadc56c3095497dda216d79f0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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] a4a6660da852a08cbcbe767df67a4f32504850ac3877aa7ae276ff51eea4e49a
[INFO] running `Command { std: "docker" "start" "-a" "a4a6660da852a08cbcbe767df67a4f32504850ac3877aa7ae276ff51eea4e49a", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.98
[INFO] [stderr]    Compiling syn v1.0.74
[INFO] [stderr]    Compiling generics v0.3.2
[INFO] [stderr]    Compiling num-bigint v0.4.0
[INFO] [stderr]    Compiling getrandom v0.2.3
[INFO] [stderr]    Compiling rand_core v0.6.3
[INFO] [stderr]    Compiling rand v0.8.4
[INFO] [stderr]    Compiling enum-ordinalize v3.1.10
[INFO] [stderr]    Compiling educe v0.4.18
[INFO] [stderr]    Compiling phantom-type v0.3.1
[INFO] [stderr]    Compiling components-arena v2.1.5 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:12:32
[INFO] [stdout]    |
[INFO] [stdout] 12 | #![cfg_attr(feature="nightly", feature(const_fn_trait_bound))]
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:15:32
[INFO] [stdout]    |
[INFO] [stdout] 15 | #![cfg_attr(feature="nightly", feature(try_reserve))]
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: use of unstable library feature 'shrink_to': new API
[INFO] [stdout]    --> src/lib.rs:273:65
[INFO] [stdout]     |
[INFO] [stdout] 273 |     pub fn shrink_to(&mut self, min_capacity: usize) { self.vec.shrink_to(min_capacity) }
[INFO] [stdout]     |                                                                 ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: see issue #56431 <https://github.com/rust-lang/rust/issues/56431> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0658.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `components-arena` due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "a4a6660da852a08cbcbe767df67a4f32504850ac3877aa7ae276ff51eea4e49a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a4a6660da852a08cbcbe767df67a4f32504850ac3877aa7ae276ff51eea4e49a", kill_on_drop: false }`
[INFO] [stdout] a4a6660da852a08cbcbe767df67a4f32504850ac3877aa7ae276ff51eea4e49a