[INFO] fetching crate loalang 0.1.20...
[INFO] testing loalang-0.1.20 against 1.49.0 for beta-1.50-1
[INFO] extracting crate loalang 0.1.20 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate loalang 0.1.20 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 loalang 0.1.20
[INFO] finished tweaking crates.io crate loalang 0.1.20
[INFO] tweaked toml for crates.io crate loalang 0.1.20 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate crates.io crate loalang 0.1.20 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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] 341ca55f7535142b9b7234d19a41019f49245bae4f4401cd798d06450f0bdaf5
[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" "341ca55f7535142b9b7234d19a41019f49245bae4f4401cd798d06450f0bdaf5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "341ca55f7535142b9b7234d19a41019f49245bae4f4401cd798d06450f0bdaf5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "341ca55f7535142b9b7234d19a41019f49245bae4f4401cd798d06450f0bdaf5", kill_on_drop: false }`
[INFO] [stdout] 341ca55f7535142b9b7234d19a41019f49245bae4f4401cd798d06450f0bdaf5
[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] 6756ef2980b3a55d18e027386e525d657360a547ae2b019a6e889857d18dad14
[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" "6756ef2980b3a55d18e027386e525d657360a547ae2b019a6e889857d18dad14", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]    Compiling num-bigint v0.2.2
[INFO] [stderr]    Compiling unicode-segmentation v1.5.0
[INFO] [stderr]    Compiling ngrammatic v0.3.1
[INFO] [stderr]    Compiling strum v0.17.1
[INFO] [stderr]    Compiling peekmore v0.4.0
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling num-integer v0.1.41
[INFO] [stderr]    Compiling num-complex v0.2.3
[INFO] [stderr]    Compiling num-iter v0.1.39
[INFO] [stderr]    Compiling num-rational v0.2.2
[INFO] [stderr]    Compiling bincode v1.2.0
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling serde_derive v1.0.101
[INFO] [stderr]    Compiling strum_macros v0.17.1
[INFO] [stderr]    Compiling serde v1.0.101
[INFO] [stderr]    Compiling num v0.2.0
[INFO] [stderr]    Compiling fraction v0.6.2
[INFO] [stderr]    Compiling loalang v0.1.20 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib/mod.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(box_patterns, try_trait)]
[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 `loalang`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "6756ef2980b3a55d18e027386e525d657360a547ae2b019a6e889857d18dad14", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6756ef2980b3a55d18e027386e525d657360a547ae2b019a6e889857d18dad14", kill_on_drop: false }`
[INFO] [stdout] 6756ef2980b3a55d18e027386e525d657360a547ae2b019a6e889857d18dad14