[INFO] fetching crate khalas 0.2.0...
[INFO] testing khalas-0.2.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate khalas 0.2.0 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate khalas 0.2.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate khalas 0.2.0
[INFO] finished tweaking crates.io crate khalas 0.2.0
[INFO] tweaked toml for crates.io crate khalas 0.2.0 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "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" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 98308cd70a3e52681275778562e999a64ffa5dc9f5ae436b1d58c09eb51b17dd
[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" "98308cd70a3e52681275778562e999a64ffa5dc9f5ae436b1d58c09eb51b17dd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "98308cd70a3e52681275778562e999a64ffa5dc9f5ae436b1d58c09eb51b17dd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "98308cd70a3e52681275778562e999a64ffa5dc9f5ae436b1d58c09eb51b17dd", kill_on_drop: false }`
[INFO] [stdout] 98308cd70a3e52681275778562e999a64ffa5dc9f5ae436b1d58c09eb51b17dd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3117f49fa1bd49f6163c0b998802d3fcf5c09f86c595d1f276f4180e57a8945c
[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" "3117f49fa1bd49f6163c0b998802d3fcf5c09f86c595d1f276f4180e57a8945c", kill_on_drop: false }`
[INFO] [stderr]    Compiling wasm-bindgen v0.2.69
[INFO] [stderr]    Compiling pulldown-cmark v0.6.1
[INFO] [stderr]    Compiling enclose v1.1.8
[INFO] [stderr]    Compiling dbg v1.0.4
[INFO] [stderr]    Compiling seed v0.6.0
[INFO] [stderr]    Compiling wasm-bindgen-backend v0.2.69
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr]    Compiling syn v0.14.9
[INFO] [stderr]    Compiling derive_rich v0.2.2
[INFO] [stderr]    Compiling serde_json v1.0.61
[INFO] [stderr]    Compiling futures-util v0.3.8
[INFO] [stderr]    Compiling phf_codegen v0.7.24
[INFO] [stderr]    Compiling palette v0.4.1
[INFO] [stderr]    Compiling wasm-bindgen-macro-support v0.2.69
[INFO] [stderr]    Compiling wasm-bindgen-macro v0.2.69
[INFO] [stderr]    Compiling futures-executor v0.3.8
[INFO] [stderr]    Compiling palette_derive v0.4.1
[INFO] [stderr]    Compiling futures v0.3.8
[INFO] [stderr]    Compiling js-sys v0.3.46
[INFO] [stderr]    Compiling console_error_panic_hook v0.1.6
[INFO] [stderr]    Compiling web-sys v0.3.46
[INFO] [stderr]    Compiling wasm-bindgen-futures v0.4.19
[INFO] [stderr]    Compiling gloo-timers v0.2.1
[INFO] [stderr]    Compiling khalas v0.2.0 (/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(decl_macro)]
[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(bool_to_option)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 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 `khalas`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "3117f49fa1bd49f6163c0b998802d3fcf5c09f86c595d1f276f4180e57a8945c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3117f49fa1bd49f6163c0b998802d3fcf5c09f86c595d1f276f4180e57a8945c", kill_on_drop: false }`
[INFO] [stdout] 3117f49fa1bd49f6163c0b998802d3fcf5c09f86c595d1f276f4180e57a8945c