[INFO] fetching crate messenger 0.1.0...
[INFO] testing messenger-0.1.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate messenger 0.1.0 into /workspace/builds/worker-88/source
[INFO] validating manifest of crates.io crate messenger 0.1.0 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate messenger 0.1.0
[INFO] finished tweaking crates.io crate messenger 0.1.0
[INFO] tweaked toml for crates.io crate messenger 0.1.0 written to /workspace/builds/worker-88/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a6c037ed3d0e26a10489846dd31071d68810d10d85e6567db1adb85756c094a1
[INFO] running `Command { std: "docker" "start" "-a" "a6c037ed3d0e26a10489846dd31071d68810d10d85e6567db1adb85756c094a1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a6c037ed3d0e26a10489846dd31071d68810d10d85e6567db1adb85756c094a1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a6c037ed3d0e26a10489846dd31071d68810d10d85e6567db1adb85756c094a1", kill_on_drop: false }`
[INFO] [stdout] a6c037ed3d0e26a10489846dd31071d68810d10d85e6567db1adb85756c094a1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 84386325a789ca89235090101977f2f41450b33288e53f9c5305b73e542950b9
[INFO] running `Command { std: "docker" "start" "-a" "84386325a789ca89235090101977f2f41450b33288e53f9c5305b73e542950b9", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling futures v0.1.31
[INFO] [stderr]    Compiling messenger 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:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(integer_atomics)]
[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:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(conservative_impl_trait)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `conservative_impl_trait` has been stable since 1.26.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/messenger.rs:9:24
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Callback<T> = Box<Fn(Vec<T>)>;
[INFO] [stdout]   |                        ^^^^^^^^^^ help: use `dyn`: `dyn Fn(Vec<T>)`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/messenger.rs:12:31
[INFO] [stdout]    |
[INFO] [stdout] 12 | type Subscribe<T> = (u32, Box<Fn(&T) -> Option<T>>);
[INFO] [stdout]    |                               ^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&T) -> Option<T>`
[INFO] [stdout]    |
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/messenger.rs:16:17
[INFO] [stdout]    |
[INFO] [stdout] 16 |     sender: Box<Sender<Item = Message<T>>>,
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sender<Item = Message<T>>`
[INFO] [stdout]    |
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: anonymous parameters are deprecated and will be removed in the next edition.
[INFO] [stdout]  --> src/sender.rs:6:20
[INFO] [stdout]   |
[INFO] [stdout] 6 |     fn send(&self, Self::Item) -> Result<(), Self::Item>;
[INFO] [stdout]   |                    ^^^^^^^^^^ help: try naming the parameter or explicitly ignoring it: `_: Self::Item`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(anonymous_parameters)]` on by default
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
[INFO] [stdout]   = note: for more information, see issue #41686 <https://github.com/rust-lang/rust/issues/41686>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 4 warnings 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 `messenger` due to 3 previous errors; 4 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "84386325a789ca89235090101977f2f41450b33288e53f9c5305b73e542950b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "84386325a789ca89235090101977f2f41450b33288e53f9c5305b73e542950b9", kill_on_drop: false }`
[INFO] [stdout] 84386325a789ca89235090101977f2f41450b33288e53f9c5305b73e542950b9