[INFO] fetching crate metron_library 0.0.1...
[INFO] documenting metron_library-0.0.1 against 1.75.0 for beta-1.76-rustdoc-1
[INFO] extracting crate metron_library 0.0.1 into /workspace/builds/worker-2-tc1/source
[INFO] validating manifest of crates.io crate metron_library 0.0.1 on toolchain 1.75.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate metron_library 0.0.1
[INFO] finished tweaking crates.io crate metron_library 0.0.1
[INFO] tweaked toml for crates.io crate metron_library 0.0.1 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded metron_core v0.0.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 85e29c5317411147272e70d587b7a6d8fe2f6cacd0e9bbf1b9efa579af5297b6
[INFO] running `Command { std: "docker" "start" "-a" "85e29c5317411147272e70d587b7a6d8fe2f6cacd0e9bbf1b9efa579af5297b6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "85e29c5317411147272e70d587b7a6d8fe2f6cacd0e9bbf1b9efa579af5297b6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "85e29c5317411147272e70d587b7a6d8fe2f6cacd0e9bbf1b9efa579af5297b6", kill_on_drop: false }`
[INFO] [stdout] 85e29c5317411147272e70d587b7a6d8fe2f6cacd0e9bbf1b9efa579af5297b6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4a8f2909226146e4b8033854be0055261101f08a2796d4801a5fd17fa62c182b
[INFO] running `Command { std: "docker" "start" "-a" "4a8f2909226146e4b8033854be0055261101f08a2796d4801a5fd17fa62c182b", kill_on_drop: false }`
[INFO] [stderr]    Compiling num-traits v0.2.17
[INFO] [stderr]     Checking metron_core v0.0.1
[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-6f17d22bba15001f/metron_core-0.0.1/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(associated_type_bounds)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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-6f17d22bba15001f/metron_core-0.0.1/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(once_cell)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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-6f17d22bba15001f/metron_core-0.0.1/src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(once_cell)]
[INFO] [stdout]   |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `metron_core` (lib) due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "4a8f2909226146e4b8033854be0055261101f08a2796d4801a5fd17fa62c182b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4a8f2909226146e4b8033854be0055261101f08a2796d4801a5fd17fa62c182b", kill_on_drop: false }`
[INFO] [stdout] 4a8f2909226146e4b8033854be0055261101f08a2796d4801a5fd17fa62c182b
