[INFO] fetching crate mattr 1.0.1...
[INFO] testing mattr-1.0.1 against 1.90.0 for beta-1.91-3
[INFO] extracting crate mattr 1.0.1 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate mattr 1.0.1
[INFO] removed 0 missing tests
[INFO] finished tweaking crates.io crate mattr 1.0.1
[INFO] tweaked toml for crates.io crate mattr 1.0.1 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate mattr 1.0.1 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] crate crates.io crate mattr 1.0.1 already has a lockfile, it will not be regenerated
[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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 10940f0daac9c556f8d50995a7238caac3501387a06742fff5dda115f03ad0e6
[INFO] running `Command { std: "docker" "start" "-a" "10940f0daac9c556f8d50995a7238caac3501387a06742fff5dda115f03ad0e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "10940f0daac9c556f8d50995a7238caac3501387a06742fff5dda115f03ad0e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "10940f0daac9c556f8d50995a7238caac3501387a06742fff5dda115f03ad0e6", kill_on_drop: false }`
[INFO] [stdout] 10940f0daac9c556f8d50995a7238caac3501387a06742fff5dda115f03ad0e6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 0fa3f0b929bbe5b33412ccb39a02f28421b9a3452bdf8882041a94ee8fb584d8
[INFO] running `Command { std: "docker" "start" "-a" "0fa3f0b929bbe5b33412ccb39a02f28421b9a3452bdf8882041a94ee8fb584d8", kill_on_drop: false }`
[INFO] [stderr]    Compiling mattr v1.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:39:1
[INFO] [stdout]    |
[INFO] [stdout] 39 | / #![feature(
[INFO] [stdout] 40 | |     const_trait_impl,
[INFO] [stdout] 41 | |     generic_const_exprs,
[INFO] [stdout] 42 | |     maybe_uninit_array_assume_init,
[INFO] [stdout] 43 | |     core_intrinsics,
[INFO] [stdout] 44 | |     const_eval_select
[INFO] [stdout] 45 | | )]
[INFO] [stdout]    | |__^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `mattr` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "0fa3f0b929bbe5b33412ccb39a02f28421b9a3452bdf8882041a94ee8fb584d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0fa3f0b929bbe5b33412ccb39a02f28421b9a3452bdf8882041a94ee8fb584d8", kill_on_drop: false }`
[INFO] [stdout] 0fa3f0b929bbe5b33412ccb39a02f28421b9a3452bdf8882041a94ee8fb584d8