[INFO] updating cached repository https://github.com/michaelmelanson/wasm-kernel
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] fe497a1d55cf5915492ed3bf5b8b1b1b00f1f97d
[INFO] testing michaelmelanson/wasm-kernel against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmichaelmelanson%2Fwasm-kernel" "work/builds/worker-0/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/michaelmelanson/wasm-kernel on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/michaelmelanson/wasm-kernel
[INFO] finished tweaking git repo https://github.com/michaelmelanson/wasm-kernel
[INFO] tweaked toml for git repo https://github.com/michaelmelanson/wasm-kernel written to work/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/michaelmelanson/wasm-kernel already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-0/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] a60b593d1680db00e07fc4a819fad3137fad3afef333904880cd71aaa02e97c2
[INFO] running `"docker" "start" "-a" "a60b593d1680db00e07fc4a819fad3137fad3afef333904880cd71aaa02e97c2"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v0.15.29
[INFO] [stderr]    Compiling ucs2 v0.1.0
[INFO] [stderr]    Compiling ux v0.1.3
[INFO] [stderr]    Compiling usize_conversions v0.2.0
[INFO] [stderr]    Compiling bit_field v0.9.0
[INFO] [stderr]    Compiling os_bootinfo v0.2.1
[INFO] [stderr]    Compiling memory_units v0.3.0
[INFO] [stderr]    Compiling parity-wasm v0.31.3
[INFO] [stderr]    Compiling hashbrown v0.1.8
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/usize_conversions-0.2.0/src/lib.rs:6:1
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![feature(i128_type)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `usize_conversions`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/hashbrown-0.1.8/src/lib.rs:15:5
[INFO] [stderr]    |
[INFO] [stderr] 15 | /     feature(
[INFO] [stderr] 16 | |         alloc,
[INFO] [stderr] 17 | |         alloc_layout_extra,
[INFO] [stderr] 18 | |         allocator_api,
[INFO] [stderr] ...  |
[INFO] [stderr] 22 | |         dropck_eyepatch
[INFO] [stderr] 23 | |     )
[INFO] [stderr]    | |_____^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/parity-wasm-0.31.3/src/lib.rs:4:35
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![cfg_attr(not(feature = "std"), feature(alloc))]
[INFO] [stderr]   |                                   ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `hashbrown`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `parity-wasm`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "a60b593d1680db00e07fc4a819fad3137fad3afef333904880cd71aaa02e97c2"`
[INFO] running `"docker" "rm" "-f" "a60b593d1680db00e07fc4a819fad3137fad3afef333904880cd71aaa02e97c2"`
[INFO] [stdout] a60b593d1680db00e07fc4a819fad3137fad3afef333904880cd71aaa02e97c2