[INFO] fetching crate rx 0.0.1...
[INFO] testing rx-0.0.1 against 1.60.0 for beta-1.61-1
[INFO] extracting crate rx 0.0.1 into /workspace/builds/worker-41/source
[INFO] validating manifest of crates.io crate rx 0.0.1 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rx 0.0.1
[INFO] finished tweaking crates.io crate rx 0.0.1
[INFO] tweaked toml for crates.io crate rx 0.0.1 written to /workspace/builds/worker-41/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-41/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-41/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 05145ea685d70f78ba9d41d6cbf70ba658f7262a9cfde2d426325ee96a8c7bd1
[INFO] running `Command { std: "docker" "start" "-a" "05145ea685d70f78ba9d41d6cbf70ba658f7262a9cfde2d426325ee96a8c7bd1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "05145ea685d70f78ba9d41d6cbf70ba658f7262a9cfde2d426325ee96a8c7bd1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "05145ea685d70f78ba9d41d6cbf70ba658f7262a9cfde2d426325ee96a8c7bd1", kill_on_drop: false }`
[INFO] [stdout] 05145ea685d70f78ba9d41d6cbf70ba658f7262a9cfde2d426325ee96a8c7bd1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-41/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-41/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" "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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0ca1d5c8b5612b45468f01696c2a799454d506d2376c5ba17d6ad184550a608d
[INFO] running `Command { std: "docker" "start" "-a" "0ca1d5c8b5612b45468f01696c2a799454d506d2376c5ba17d6ad184550a608d", kill_on_drop: false }`
[INFO] [stderr]    Compiling rx v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:16:1
[INFO] [stdout]    |
[INFO] [stdout] 16 | #![feature(fn_traits, unboxed_closures)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/subject.rs:17:24
[INFO] [stdout]    |
[INFO] [stdout] 17 |     observers: Vec<Box<BoxedObserver<T, E>>>,
[INFO] [stdout]    |                        ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 17 -     observers: Vec<Box<BoxedObserver<T, E>>>,
[INFO] [stdout] 17 +     observers: Vec<Box<dyn BoxedObserver<T, E>>>,
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rx` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "0ca1d5c8b5612b45468f01696c2a799454d506d2376c5ba17d6ad184550a608d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0ca1d5c8b5612b45468f01696c2a799454d506d2376c5ba17d6ad184550a608d", kill_on_drop: false }`
[INFO] [stdout] 0ca1d5c8b5612b45468f01696c2a799454d506d2376c5ba17d6ad184550a608d