[INFO] fetching crate aces 0.0.13...
[INFO] testing aces-0.0.13 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate aces 0.0.13 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate aces 0.0.13 on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate aces 0.0.13
[INFO] finished tweaking crates.io crate aces 0.0.13
[INFO] tweaked toml for crates.io crate aces 0.0.13 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded partial_ref v0.3.2
[INFO] [stderr]   Downloaded varisat-formula v0.2.2
[INFO] [stderr]   Downloaded varisat v0.2.2
[INFO] [stderr]   Downloaded partial_ref_derive v0.3.2
[INFO] [stderr]   Downloaded varisat-internal-proof v0.2.2
[INFO] [stderr]   Downloaded varisat-internal-macros v0.2.2
[INFO] [stderr]   Downloaded varisat-dimacs v0.2.2
[INFO] [stderr]   Downloaded vec_mut_scan v0.3.0
[INFO] [stderr]   Downloaded varisat-checker v0.2.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8f4c811d1083bdb5885023bc55d813be6da13c76f8e4627fcada32a45532387f
[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" "8f4c811d1083bdb5885023bc55d813be6da13c76f8e4627fcada32a45532387f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8f4c811d1083bdb5885023bc55d813be6da13c76f8e4627fcada32a45532387f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8f4c811d1083bdb5885023bc55d813be6da13c76f8e4627fcada32a45532387f", kill_on_drop: false }`
[INFO] [stdout] 8f4c811d1083bdb5885023bc55d813be6da13c76f8e4627fcada32a45532387f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4d4e793cb2f2d1b9592439bd6b3dbf1495554cd03e5e080db4ed80683e53c0b2
[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" "4d4e793cb2f2d1b9592439bd6b3dbf1495554cd03e5e080db4ed80683e53c0b2", kill_on_drop: false }`
[INFO] [stderr]    Compiling varisat-formula v0.2.2
[INFO] [stderr]    Compiling rustc-hash v1.1.0
[INFO] [stderr]    Compiling vec_mut_scan v0.3.0
[INFO] [stderr]    Compiling leb128 v0.2.4
[INFO] [stderr]    Compiling bit-vec v0.6.3
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling yaml-rust v0.4.5
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling varisat v0.2.2
[INFO] [stderr]    Compiling colored v1.9.3
[INFO] [stderr]    Compiling thiserror-impl v1.0.23
[INFO] [stderr]    Compiling partial_ref_derive v0.3.2
[INFO] [stderr]    Compiling serde v1.0.118
[INFO] [stderr]    Compiling varisat-internal-macros v0.2.2
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling varisat-internal-proof v0.2.2
[INFO] [stderr]    Compiling fern v0.6.0
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling partial_ref v0.3.2
[INFO] [stderr]    Compiling thiserror v1.0.23
[INFO] [stderr]    Compiling varisat-dimacs v0.2.2
[INFO] [stderr]    Compiling ordered-float v2.0.1
[INFO] [stderr]    Compiling varisat-checker v0.2.2
[INFO] [stderr]    Compiling string_cache v0.8.1
[INFO] [stderr]    Compiling aces v0.0.13 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(bool_to_option)]
[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: could not compile `aces`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "4d4e793cb2f2d1b9592439bd6b3dbf1495554cd03e5e080db4ed80683e53c0b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d4e793cb2f2d1b9592439bd6b3dbf1495554cd03e5e080db4ed80683e53c0b2", kill_on_drop: false }`
[INFO] [stdout] 4d4e793cb2f2d1b9592439bd6b3dbf1495554cd03e5e080db4ed80683e53c0b2