[INFO] fetching crate cbuffer 0.3.1...
[INFO] testing cbuffer-0.3.1 against 1.90.0 for beta-1.91-3
[INFO] extracting crate cbuffer 0.3.1 into /workspace/builds/worker-2-tc1/source
[INFO] removed /workspace/builds/worker-2-tc1/source/rust-toolchain.toml
[INFO] started tweaking crates.io crate cbuffer 0.3.1
[INFO] finished tweaking crates.io crate cbuffer 0.3.1
[INFO] tweaked toml for crates.io crate cbuffer 0.3.1 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate cbuffer 0.3.1 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] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 2 packages to latest compatible versions
[INFO] [stderr]       Adding uninit v0.4.0 (available: v0.6.2)
[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]  Downloading crates ...
[INFO] [stderr]   Downloaded uninit v0.4.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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] 285bcb233861c2550056dac93cc263cd236778c1f95bda5580177113d2da97f4
[INFO] running `Command { std: "docker" "start" "-a" "285bcb233861c2550056dac93cc263cd236778c1f95bda5580177113d2da97f4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "285bcb233861c2550056dac93cc263cd236778c1f95bda5580177113d2da97f4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "285bcb233861c2550056dac93cc263cd236778c1f95bda5580177113d2da97f4", kill_on_drop: false }`
[INFO] [stdout] 285bcb233861c2550056dac93cc263cd236778c1f95bda5580177113d2da97f4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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] ee1751337066955155debde0e34ddcf1db962f2e41b4d5e7f6bc90eca985e13f
[INFO] running `Command { std: "docker" "start" "-a" "ee1751337066955155debde0e34ddcf1db962f2e41b4d5e7f6bc90eca985e13f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.176
[INFO] [stderr]    Compiling uninit v0.4.0
[INFO] [stderr]    Compiling cbuffer v0.3.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(maybe_uninit_slice)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no function or associated item named `slice_assume_init_mut` found for union `MaybeUninit` in the current scope
[INFO] [stdout]    --> src/lib.rs:138:22
[INFO] [stdout]     |
[INFO] [stdout] 138 |         MaybeUninit::slice_assume_init_mut(&mut self[..len])
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^ function or associated item not found in `MaybeUninit<_>`
[INFO] [stdout]     |
[INFO] [stdout] note: if you're trying to build a new `MaybeUninit<_>` consider using one of the following associated functions:
[INFO] [stdout]       MaybeUninit::<T>::new
[INFO] [stdout]       MaybeUninit::<T>::uninit
[INFO] [stdout]       MaybeUninit::<T>::zeroed
[INFO] [stdout]    --> /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/mem/maybe_uninit.rs:307:5
[INFO] [stdout] help: there is a method `assume_init_mut` with a similar name, but with different arguments
[INFO] [stdout]    --> /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/mem/maybe_uninit.rs:900:5
[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 `cbuffer` (lib) due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "ee1751337066955155debde0e34ddcf1db962f2e41b4d5e7f6bc90eca985e13f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ee1751337066955155debde0e34ddcf1db962f2e41b4d5e7f6bc90eca985e13f", kill_on_drop: false }`
[INFO] [stdout] ee1751337066955155debde0e34ddcf1db962f2e41b4d5e7f6bc90eca985e13f