[INFO] fetching crate mattr 1.0.1...
[INFO] testing mattr-1.0.1 against 1.91.0 for beta-1.92-2
[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 1.91.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "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" "+1.91.0" "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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1eff75958596a0ec33ef6213ddb92f790ceb5b260e19be08fb8e55ed298270a5
[INFO] running `Command { std: "docker" "start" "-a" "1eff75958596a0ec33ef6213ddb92f790ceb5b260e19be08fb8e55ed298270a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1eff75958596a0ec33ef6213ddb92f790ceb5b260e19be08fb8e55ed298270a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1eff75958596a0ec33ef6213ddb92f790ceb5b260e19be08fb8e55ed298270a5", kill_on_drop: false }`
[INFO] [stdout] 1eff75958596a0ec33ef6213ddb92f790ceb5b260e19be08fb8e55ed298270a5
[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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 88964340c3885a51f9dad645a731ae7f05ed5c0ceb037875acc134bf090d444b
[INFO] running `Command { std: "docker" "start" "-a" "88964340c3885a51f9dad645a731ae7f05ed5c0ceb037875acc134bf090d444b", 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" "88964340c3885a51f9dad645a731ae7f05ed5c0ceb037875acc134bf090d444b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "88964340c3885a51f9dad645a731ae7f05ed5c0ceb037875acc134bf090d444b", kill_on_drop: false }`
[INFO] [stdout] 88964340c3885a51f9dad645a731ae7f05ed5c0ceb037875acc134bf090d444b