[INFO] fetching crate writedown 0.1.0...
[INFO] testing writedown-0.1.0 against 1.90.0 for beta-1.91-3
[INFO] extracting crate writedown 0.1.0 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate writedown 0.1.0
[INFO] finished tweaking crates.io crate writedown 0.1.0
[INFO] tweaked toml for crates.io crate writedown 0.1.0 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate writedown 0.1.0 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 writedown 0.1.0 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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded libc v0.2.91
[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] 9e2a3dd695e2e80981a8ed534c692f7f5f76c2bb7ba857bf934b190f31bc9daa
[INFO] running `Command { std: "docker" "start" "-a" "9e2a3dd695e2e80981a8ed534c692f7f5f76c2bb7ba857bf934b190f31bc9daa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9e2a3dd695e2e80981a8ed534c692f7f5f76c2bb7ba857bf934b190f31bc9daa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9e2a3dd695e2e80981a8ed534c692f7f5f76c2bb7ba857bf934b190f31bc9daa", kill_on_drop: false }`
[INFO] [stdout] 9e2a3dd695e2e80981a8ed534c692f7f5f76c2bb7ba857bf934b190f31bc9daa
[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] a50d9b03cfb96acb8bf100d3d936d1190d2aed9410c2ff20807886d5d6f83490
[INFO] running `Command { std: "docker" "start" "-a" "a50d9b03cfb96acb8bf100d3d936d1190d2aed9410c2ff20807886d5d6f83490", kill_on_drop: false }`
[INFO] [stderr]    Compiling writedown v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(assert_matches)]
[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 `writedown` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "a50d9b03cfb96acb8bf100d3d936d1190d2aed9410c2ff20807886d5d6f83490", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a50d9b03cfb96acb8bf100d3d936d1190d2aed9410c2ff20807886d5d6f83490", kill_on_drop: false }`
[INFO] [stdout] a50d9b03cfb96acb8bf100d3d936d1190d2aed9410c2ff20807886d5d6f83490