[INFO] fetching crate xlsx 0.1.0...
[INFO] testing xlsx-0.1.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate xlsx 0.1.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate xlsx 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 xlsx 0.1.0
[INFO] finished tweaking crates.io crate xlsx 0.1.0
[INFO] tweaked toml for crates.io crate xlsx 0.1.0 written to /workspace/builds/worker-9/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] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 40c1cad84502c0ec41943054aaf87833a677aa0d9a8e065787cd1f1b7c765c8e
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "40c1cad84502c0ec41943054aaf87833a677aa0d9a8e065787cd1f1b7c765c8e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "40c1cad84502c0ec41943054aaf87833a677aa0d9a8e065787cd1f1b7c765c8e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "40c1cad84502c0ec41943054aaf87833a677aa0d9a8e065787cd1f1b7c765c8e", kill_on_drop: false }`
[INFO] [stdout] 40c1cad84502c0ec41943054aaf87833a677aa0d9a8e065787cd1f1b7c765c8e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 1151d95857fc0760e1b83fd6127a31f91acb48798d4566059b4553e15c5a36d7
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "1151d95857fc0760e1b83fd6127a31f91acb48798d4566059b4553e15c5a36d7", kill_on_drop: false }`
[INFO] [stderr]    Compiling podio v0.1.7
[INFO] [stderr]    Compiling xml_writer v0.1.4
[INFO] [stderr]    Compiling bzip2-sys v0.1.11+1.0.8
[INFO] [stderr]    Compiling miniz-sys v0.1.12
[INFO] [stderr]    Compiling msdos_time v0.1.6
[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/xml_writer-0.1.4/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(unicode)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 1 argument but 0 arguments were supplied
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xml_writer-0.1.4/src/xml_writer.rs:145:49
[INFO] [stdout]     |
[INFO] [stdout] 145 |                 _    => try!(self.write_slice(c.encode_utf8().as_slice()))
[INFO] [stdout]     |                                                 ^^^^^^^^^^^- supplied 0 arguments
[INFO] [stdout]     |                                                 |
[INFO] [stdout]     |                                                 expected 1 argument
[INFO] [stdout]     |
[INFO] [stdout] note: associated function defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for mutable reference `&mut str` in the current scope
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/xml_writer-0.1.4/src/xml_writer.rs:145:63
[INFO] [stdout]     |
[INFO] [stdout] 145 |                 _    => try!(self.write_slice(c.encode_utf8().as_slice()))
[INFO] [stdout]     |                                                               ^^^^^^^^ method not found in `&mut str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0061, E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0061`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `xml_writer` due to 4 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "1151d95857fc0760e1b83fd6127a31f91acb48798d4566059b4553e15c5a36d7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1151d95857fc0760e1b83fd6127a31f91acb48798d4566059b4553e15c5a36d7", kill_on_drop: false }`
[INFO] [stdout] 1151d95857fc0760e1b83fd6127a31f91acb48798d4566059b4553e15c5a36d7