[INFO] fetching crate array-vec 0.1.3...
[INFO] testing array-vec-0.1.3 against 1.54.0 for beta-1.55-1
[INFO] extracting crate array-vec 0.1.3 into /workspace/builds/worker-66/source
[INFO] validating manifest of crates.io crate array-vec 0.1.3 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate array-vec 0.1.3
[INFO] finished tweaking crates.io crate array-vec 0.1.3
[INFO] tweaked toml for crates.io crate array-vec 0.1.3 written to /workspace/builds/worker-66/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "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" "+1.54.0" "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-66/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-66/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9ccc63b8abbf9584602ac4800c3a2cd7d14ce86ca4421a3e85f0bf1cf51345a6
[INFO] running `Command { std: "docker" "start" "-a" "9ccc63b8abbf9584602ac4800c3a2cd7d14ce86ca4421a3e85f0bf1cf51345a6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9ccc63b8abbf9584602ac4800c3a2cd7d14ce86ca4421a3e85f0bf1cf51345a6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9ccc63b8abbf9584602ac4800c3a2cd7d14ce86ca4421a3e85f0bf1cf51345a6", kill_on_drop: false }`
[INFO] [stdout] 9ccc63b8abbf9584602ac4800c3a2cd7d14ce86ca4421a3e85f0bf1cf51345a6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-66/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-66/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8e421020c662ccf1b31941f678e637b953706c2535a8a1d7f005e325c887df2a
[INFO] running `Command { std: "docker" "start" "-a" "8e421020c662ccf1b31941f678e637b953706c2535a8a1d7f005e325c887df2a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling array-vec 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(const_generics, specialization, maybe_uninit_extra, maybe_uninit_slice)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `const_generics` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(const_generics, specialization, maybe_uninit_extra, maybe_uninit_slice)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:1:28
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(const_generics, specialization, maybe_uninit_extra, maybe_uninit_slice)]
[INFO] [stdout]   |                            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]   = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no function or associated item named `first_ptr` found for union `MaybeUninit` in the current scope
[INFO] [stdout]   --> src/lib.rs:36:22
[INFO] [stdout]    |
[INFO] [stdout] 36 |         MaybeUninit::first_ptr(&self.arr)
[INFO] [stdout]    |                      ^^^^^^^^^ function or associated item not found in `MaybeUninit<_>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no function or associated item named `first_ptr_mut` found for union `MaybeUninit` in the current scope
[INFO] [stdout]   --> src/lib.rs:41:22
[INFO] [stdout]    |
[INFO] [stdout] 41 |         MaybeUninit::first_ptr_mut(&mut self.arr)
[INFO] [stdout]    |                      ^^^^^^^^^^^^^ function or associated item not found in `MaybeUninit<_>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors; 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `array-vec`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "8e421020c662ccf1b31941f678e637b953706c2535a8a1d7f005e325c887df2a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8e421020c662ccf1b31941f678e637b953706c2535a8a1d7f005e325c887df2a", kill_on_drop: false }`
[INFO] [stdout] 8e421020c662ccf1b31941f678e637b953706c2535a8a1d7f005e325c887df2a
