[INFO] fetching crate unmp-link 0.7.0...
[INFO] documenting unmp-link-0.7.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate unmp-link 0.7.0 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate unmp-link 0.7.0 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 crates.io crate unmp-link 0.7.0
[INFO] finished tweaking crates.io crate unmp-link 0.7.0
[INFO] tweaked toml for crates.io crate unmp-link 0.7.0 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] [stdout] af2a676d55addbb884a5c31cc6a31a94bba1f2bdc7f8f61fbc91577a6e7c8c5d
[INFO] running `Command { std: "docker" "start" "-a" "af2a676d55addbb884a5c31cc6a31a94bba1f2bdc7f8f61fbc91577a6e7c8c5d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "af2a676d55addbb884a5c31cc6a31a94bba1f2bdc7f8f61fbc91577a6e7c8c5d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "af2a676d55addbb884a5c31cc6a31a94bba1f2bdc7f8f61fbc91577a6e7c8c5d", kill_on_drop: false }`
[INFO] [stdout] af2a676d55addbb884a5c31cc6a31a94bba1f2bdc7f8f61fbc91577a6e7c8c5d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] 9b958a5cb509e510c9c45c39fd2bb658c9e6f061eea07008f2e70eca5194a1ed
[INFO] running `Command { std: "docker" "start" "-a" "9b958a5cb509e510c9c45c39fd2bb658c9e6f061eea07008f2e70eca5194a1ed", kill_on_drop: false }`
[INFO] [stderr]    Compiling futures-core v0.3.21
[INFO] [stderr]     Checking fixed-queue v0.3.11
[INFO] [stderr]    Compiling lock_api v0.4.7
[INFO] [stderr]     Checking spin v0.9.3
[INFO] [stderr]     Checking futures-intrusive v0.4.0
[INFO] [stderr]  Documenting unmp-link v0.7.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(const_btree_new)]
[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 document `unmp-link`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name unmp_link src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=0b003dd101d4c131 -L dependency=/opt/rustwide/target/debug/deps --extern cfg_if=/opt/rustwide/target/debug/deps/libcfg_if-dcce77079dd8fe1e.rmeta --extern fixed_queue=/opt/rustwide/target/debug/deps/libfixed_queue-046eb324a3033d3f.rmeta --extern futures_intrusive=/opt/rustwide/target/debug/deps/libfutures_intrusive-5e7cbf356c47387e.rmeta --extern spin=/opt/rustwide/target/debug/deps/libspin-4b698e19990ed30e.rmeta --cap-lints=warn --crate-version 0.7.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "9b958a5cb509e510c9c45c39fd2bb658c9e6f061eea07008f2e70eca5194a1ed", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9b958a5cb509e510c9c45c39fd2bb658c9e6f061eea07008f2e70eca5194a1ed", kill_on_drop: false }`
[INFO] [stdout] 9b958a5cb509e510c9c45c39fd2bb658c9e6f061eea07008f2e70eca5194a1ed