[INFO] cloning repository https://github.com/ula-lang/ula
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ula-lang/ula" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fula-lang%2Fula", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fula-lang%2Fula'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 13578eead1253ff798653507cf45fb39fbe17743
[INFO] documenting ula-lang/ula against 1.46.0 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fula-lang%2Fula" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ula-lang/ula on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ula-lang/ula
[INFO] finished tweaking git repo https://github.com/ula-lang/ula
[INFO] tweaked toml for git repo https://github.com/ula-lang/ula written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/ula-lang/ula already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5245a2092904c68b7bd0e723a0f9d94c7fd0c14528245656933077842685dafe
[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" "5245a2092904c68b7bd0e723a0f9d94c7fd0c14528245656933077842685dafe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5245a2092904c68b7bd0e723a0f9d94c7fd0c14528245656933077842685dafe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5245a2092904c68b7bd0e723a0f9d94c7fd0c14528245656933077842685dafe", kill_on_drop: false }`
[INFO] [stdout] 5245a2092904c68b7bd0e723a0f9d94c7fd0c14528245656933077842685dafe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "RUSTDOCFLAGS=--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" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4c16138636fef073242b4febcbc6e3997b8824153d22f3b2edfed04456812ba7
[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" "4c16138636fef073242b4febcbc6e3997b8824153d22f3b2edfed04456812ba7", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.20
[INFO] [stderr]    Compiling bit-vec v0.4.4
[INFO] [stderr]    Compiling vec_map v0.6.0
[INFO] [stderr]    Compiling lalr v0.0.2
[INFO] [stderr]     Checking getrandom v0.1.13
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]    Compiling bit-set v0.4.0
[INFO] [stderr]    Compiling redfa v0.0.2
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]    Compiling quote v0.6.8
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling syn v0.14.9
[INFO] [stderr]    Compiling derivative v1.0.3
[INFO] [stderr]    Compiling plex v0.2.3
[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/plex-0.2.3/src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(proc_macro_diagnostic)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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/plex-0.2.3/src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(proc_macro_span)]
[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 `plex`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "4c16138636fef073242b4febcbc6e3997b8824153d22f3b2edfed04456812ba7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4c16138636fef073242b4febcbc6e3997b8824153d22f3b2edfed04456812ba7", kill_on_drop: false }`
[INFO] [stdout] 4c16138636fef073242b4febcbc6e3997b8824153d22f3b2edfed04456812ba7