[INFO] fetching crate lain 0.5.2...
[INFO] testing lain-0.5.2 against 1.47.0 for beta-1.48-1
[INFO] extracting crate lain 0.5.2 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate lain 0.5.2 on toolchain 1.47.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate lain 0.5.2
[INFO] finished tweaking crates.io crate lain 0.5.2
[INFO] tweaked toml for crates.io crate lain 0.5.2 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ae635226f7d7729b90eb51465d952057939988240cb48ae3256b7a04b3315d9b
[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" "ae635226f7d7729b90eb51465d952057939988240cb48ae3256b7a04b3315d9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ae635226f7d7729b90eb51465d952057939988240cb48ae3256b7a04b3315d9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ae635226f7d7729b90eb51465d952057939988240cb48ae3256b7a04b3315d9b", kill_on_drop: false }`
[INFO] [stdout] ae635226f7d7729b90eb51465d952057939988240cb48ae3256b7a04b3315d9b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "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] c93fdac44c35fc2a59ab1a4fb63fb5edf325e1035f4fdc4e3cfa77fec68e126e
[INFO] running `Command { std: "docker" "start" "-a" "c93fdac44c35fc2a59ab1a4fb63fb5edf325e1035f4fdc4e3cfa77fec68e126e", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.79
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling proc-macro-hack-impl v0.4.2
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling num-derive v0.2.5
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]    Compiling num-integer v0.1.43
[INFO] [stderr]    Compiling num-bigint v0.2.6
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling num-iter v0.1.41
[INFO] [stderr]    Compiling num-complex v0.2.4
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling proc-macro-hack v0.4.2
[INFO] [stderr]    Compiling mashup-impl v0.1.12
[INFO] [stderr]    Compiling field-offset v0.3.2
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_pcg v0.2.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling mashup v0.1.12
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling num v0.2.1
[INFO] [stderr]    Compiling lain_derive v0.5.2
[INFO] [stderr]    Compiling lain v0.5.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:101:1
[INFO] [stdout]     |
[INFO] [stdout] 101 | #![feature(specialization)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]    --> src/lib.rs:101:12
[INFO] [stdout]     |
[INFO] [stdout] 101 | #![feature(specialization)]
[INFO] [stdout]     |            ^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]     = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning 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 `lain`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "c93fdac44c35fc2a59ab1a4fb63fb5edf325e1035f4fdc4e3cfa77fec68e126e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c93fdac44c35fc2a59ab1a4fb63fb5edf325e1035f4fdc4e3cfa77fec68e126e", kill_on_drop: false }`
[INFO] [stdout] c93fdac44c35fc2a59ab1a4fb63fb5edf325e1035f4fdc4e3cfa77fec68e126e
