[INFO] fetching crate loader 0.2.1...
[INFO] testing loader-0.2.1 against 1.90.0 for beta-1.91-3
[INFO] extracting crate loader 0.2.1 into /workspace/builds/worker-4-tc1/source
[INFO] started tweaking crates.io crate loader 0.2.1
[INFO] finished tweaking crates.io crate loader 0.2.1
[INFO] tweaked toml for crates.io crate loader 0.2.1 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate loader 0.2.1 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] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 1 package to latest compatible version
[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-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] 5500732c7643f4c1758524f835701a819b5dd7f45a65d7f6d70c236587d5c3be
[INFO] running `Command { std: "docker" "start" "-a" "5500732c7643f4c1758524f835701a819b5dd7f45a65d7f6d70c236587d5c3be", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5500732c7643f4c1758524f835701a819b5dd7f45a65d7f6d70c236587d5c3be", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5500732c7643f4c1758524f835701a819b5dd7f45a65d7f6d70c236587d5c3be", kill_on_drop: false }`
[INFO] [stdout] 5500732c7643f4c1758524f835701a819b5dd7f45a65d7f6d70c236587d5c3be
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] ef629e9cf63e8ac7bddcca58e145e77a4c1c185d054f3ff89b2147a5aebcd4e4
[INFO] running `Command { std: "docker" "start" "-a" "ef629e9cf63e8ac7bddcca58e145e77a4c1c185d054f3ff89b2147a5aebcd4e4", kill_on_drop: false }`
[INFO] [stderr]    Compiling loader v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:33
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![cfg_attr(feature = "unsize", feature(unsize))]
[INFO] [stdout]   |                                 ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:33
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(feature = "unsize", feature(coerce_unsized))]
[INFO] [stdout]   |                                 ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:36
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![cfg_attr(feature = "fn_traits", feature(unboxed_closures))]
[INFO] [stdout]   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:4:36
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "fn_traits", feature(fn_traits))]
[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 `loader` (lib) due to 4 previous errors
[INFO] running `Command { std: "docker" "inspect" "ef629e9cf63e8ac7bddcca58e145e77a4c1c185d054f3ff89b2147a5aebcd4e4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef629e9cf63e8ac7bddcca58e145e77a4c1c185d054f3ff89b2147a5aebcd4e4", kill_on_drop: false }`
[INFO] [stdout] ef629e9cf63e8ac7bddcca58e145e77a4c1c185d054f3ff89b2147a5aebcd4e4