[INFO] fetching crate free-algebra 0.1.0...
[INFO] checking free-algebra-0.1.0 against 1.95.0 for pr-155915
[INFO] extracting crate free-algebra 0.1.0 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate free-algebra 0.1.0
[INFO] finished tweaking crates.io crate free-algebra 0.1.0
[INFO] tweaked toml for crates.io crate free-algebra 0.1.0 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate free-algebra 0.1.0 on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "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" "+1.95.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 8 packages to latest compatible versions
[INFO] [stderr]       Adding derivative v1.0.4 (available: v2.2.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded derivative v1.0.4
[INFO] [stderr]   Downloaded maths-traits v0.2.1
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 961b2ce803aea83d81dbb4c811ffee801f7b0b65c743db0df517b57d6619c992
[INFO] running `Command { std: "docker" "start" "-a" "961b2ce803aea83d81dbb4c811ffee801f7b0b65c743db0df517b57d6619c992", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "961b2ce803aea83d81dbb4c811ffee801f7b0b65c743db0df517b57d6619c992", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "961b2ce803aea83d81dbb4c811ffee801f7b0b65c743db0df517b57d6619c992", kill_on_drop: false }`
[INFO] [stdout] 961b2ce803aea83d81dbb4c811ffee801f7b0b65c743db0df517b57d6619c992
[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=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 263f102cdf69d8f4ba8f31049a9f94fe0e14cd9b79639163267372cbab9141a1
[INFO] running `Command { std: "docker" "start" "-a" "263f102cdf69d8f4ba8f31049a9f94fe0e14cd9b79639163267372cbab9141a1", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]     Checking maths-traits v0.2.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/maths-traits-0.2.1/src/lib.rs:317:1
[INFO] [stdout]     |
[INFO] [stdout] 317 | #![feature(trait_alias)]
[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 `maths-traits` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "263f102cdf69d8f4ba8f31049a9f94fe0e14cd9b79639163267372cbab9141a1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "263f102cdf69d8f4ba8f31049a9f94fe0e14cd9b79639163267372cbab9141a1", kill_on_drop: false }`
[INFO] [stdout] 263f102cdf69d8f4ba8f31049a9f94fe0e14cd9b79639163267372cbab9141a1