[INFO] fetching crate prusto 0.3.3...
[INFO] testing prusto-0.3.3 against 1.55.0 for beta-1.56-1
[INFO] extracting crate prusto 0.3.3 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate prusto 0.3.3 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 prusto 0.3.3
[INFO] finished tweaking crates.io crate prusto 0.3.3
[INFO] tweaked toml for crates.io crate prusto 0.3.3 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate crates.io crate prusto 0.3.3 already has a lockfile, it will not be regenerated
[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]  Downloading crates ...
[INFO] [stderr]   Downloaded num-bigint v0.3.2
[INFO] [stderr]   Downloaded bigdecimal v0.2.0
[INFO] [stderr]   Downloaded derive_more v0.99.14
[INFO] [stderr]   Downloaded trybuild v1.0.42
[INFO] [stderr]   Downloaded iterable v0.4.1
[INFO] [stderr]   Downloaded prusto-macros v0.1.0
[INFO] [stderr]   Downloaded futures-async-stream-macro v0.2.5
[INFO] [stderr]   Downloaded futures-async-stream v0.2.5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 31b15c75e8bd188b06bda02de5a17ff84dca51d69b2845c41dc7eb8d0313e20c
[INFO] running `Command { std: "docker" "start" "-a" "31b15c75e8bd188b06bda02de5a17ff84dca51d69b2845c41dc7eb8d0313e20c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "31b15c75e8bd188b06bda02de5a17ff84dca51d69b2845c41dc7eb8d0313e20c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31b15c75e8bd188b06bda02de5a17ff84dca51d69b2845c41dc7eb8d0313e20c", kill_on_drop: false }`
[INFO] [stdout] 31b15c75e8bd188b06bda02de5a17ff84dca51d69b2845c41dc7eb8d0313e20c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 210da65a8db5918ca460e1d1479e0896ffe73cdc84f40316cef0f395cbc4b51f
[INFO] running `Command { std: "docker" "start" "-a" "210da65a8db5918ca460e1d1479e0896ffe73cdc84f40316cef0f395cbc4b51f", kill_on_drop: false }`
[INFO] [stderr]    Compiling tokio v1.6.0
[INFO] [stderr]    Compiling futures-util v0.3.15
[INFO] [stderr]    Compiling parking_lot_core v0.8.3
[INFO] [stderr]    Compiling signal-hook-registry v1.3.0
[INFO] [stderr]    Compiling ring v0.16.20
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling iterable v0.4.1
[INFO] [stderr]    Compiling futures-async-stream-macro v0.2.5
[INFO] [stderr]    Compiling prusto-macros v0.1.0
[INFO] [stderr]    Compiling parse-zoneinfo v0.3.0
[INFO] [stderr]    Compiling bigdecimal v0.2.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(try_trait_v2)]
[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/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(extend_one)]
[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/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(associated_type_defaults)]
[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/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(iter_map_while)]
[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/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(maybe_uninit_uninit_array)]
[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/github.com-1ecc6299db9ec823/iterable-0.4.1/src/lib.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(generic_associated_types)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 6 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 `iterable` due to 7 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/futures-async-stream-macro-0.2.5/src/lib.rs:13:1
[INFO] [stdout]    |
[INFO] [stdout] 13 | #![feature(proc_macro_def_site)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "210da65a8db5918ca460e1d1479e0896ffe73cdc84f40316cef0f395cbc4b51f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "210da65a8db5918ca460e1d1479e0896ffe73cdc84f40316cef0f395cbc4b51f", kill_on_drop: false }`
[INFO] [stdout] 210da65a8db5918ca460e1d1479e0896ffe73cdc84f40316cef0f395cbc4b51f