[INFO] cloning repository https://github.com/EliasHolzmann/include_optional
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/EliasHolzmann/include_optional" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEliasHolzmann%2Finclude_optional", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEliasHolzmann%2Finclude_optional'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 301f14a169fe0ce76450629ff2d0b5dda4c4af8d
[INFO] documenting EliasHolzmann/include_optional against 1.61.0 for beta-1.62-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEliasHolzmann%2Finclude_optional" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/EliasHolzmann/include_optional on toolchain 1.61.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/EliasHolzmann/include_optional
[INFO] finished tweaking git repo https://github.com/EliasHolzmann/include_optional
[INFO] tweaked toml for git repo https://github.com/EliasHolzmann/include_optional written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/EliasHolzmann/include_optional already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded trybuild v1.0.43
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "metadata" "--no-deps" "--format-version=1", 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] dd9099563fedcccbf7cb927ba33ce5a1cd2ca45803e123c78ac108f8cd0ee46e
[INFO] running `Command { std: "docker" "start" "-a" "dd9099563fedcccbf7cb927ba33ce5a1cd2ca45803e123c78ac108f8cd0ee46e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dd9099563fedcccbf7cb927ba33ce5a1cd2ca45803e123c78ac108f8cd0ee46e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dd9099563fedcccbf7cb927ba33ce5a1cd2ca45803e123c78ac108f8cd0ee46e", kill_on_drop: false }`
[INFO] [stdout] dd9099563fedcccbf7cb927ba33ce5a1cd2ca45803e123c78ac108f8cd0ee46e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8afc0f7b89228f0869293ec9755dca5125e5cc54fe4e833842b1166e61e4e8b5
[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" "8afc0f7b89228f0869293ec9755dca5125e5cc54fe4e833842b1166e61e4e8b5", kill_on_drop: false }`
[INFO] [stderr]     Checking unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.74
[INFO] [stderr]     Checking proc-macro2 v1.0.28
[INFO] [stderr]     Checking quote v1.0.9
[INFO] [stderr]  Documenting include_optional v1.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:4:12
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(proc_macro_span, path_try_exists)]
[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:4:29
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(proc_macro_span, path_try_exists)]
[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 document `include_optional`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type proc-macro --crate-name include_optional src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=ab3aa38a82fb0ab7 -L dependency=/opt/rustwide/target/debug/deps --extern quote=/opt/rustwide/target/debug/deps/libquote-48e3b699153f2ed0.rmeta --extern syn=/opt/rustwide/target/debug/deps/libsyn-23228996d2ae54ff.rmeta --extern proc_macro --cap-lints=warn --crate-version 1.0.1` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "8afc0f7b89228f0869293ec9755dca5125e5cc54fe4e833842b1166e61e4e8b5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8afc0f7b89228f0869293ec9755dca5125e5cc54fe4e833842b1166e61e4e8b5", kill_on_drop: false }`
[INFO] [stdout] 8afc0f7b89228f0869293ec9755dca5125e5cc54fe4e833842b1166e61e4e8b5