[INFO] fetching crate directory-tree 0.0.1...
[INFO] documenting directory-tree-0.0.1 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate directory-tree 0.0.1 into /workspace/builds/worker-20/source
[INFO] validating manifest of crates.io crate directory-tree 0.0.1 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate directory-tree 0.0.1
[INFO] finished tweaking crates.io crate directory-tree 0.0.1
[INFO] tweaked toml for crates.io crate directory-tree 0.0.1 written to /workspace/builds/worker-20/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c20dfdce3481d5469c7fe9bb6363efe22cd640470f136c9f8d430daa896e6d9c
[INFO] running `Command { std: "docker" "start" "-a" "c20dfdce3481d5469c7fe9bb6363efe22cd640470f136c9f8d430daa896e6d9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c20dfdce3481d5469c7fe9bb6363efe22cd640470f136c9f8d430daa896e6d9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c20dfdce3481d5469c7fe9bb6363efe22cd640470f136c9f8d430daa896e6d9c", kill_on_drop: false }`
[INFO] [stdout] c20dfdce3481d5469c7fe9bb6363efe22cd640470f136c9f8d430daa896e6d9c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-20/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dc0db2615d50656db224867a77719416bb2703003c051e7fe8f3b5c062b943ff
[INFO] running `Command { std: "docker" "start" "-a" "dc0db2615d50656db224867a77719416bb2703003c051e7fe8f3b5c062b943ff", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling neon-build v0.8.3
[INFO] [stderr]     Checking smallvec v1.6.1
[INFO] [stderr]     Checking semver-parser v0.7.0
[INFO] [stderr]    Compiling serde_json v1.0.66
[INFO] [stderr]     Checking cslice v0.2.0
[INFO] [stderr]     Checking libloading v0.6.7
[INFO] [stderr]    Compiling syn v1.0.74
[INFO] [stderr]     Checking semver v0.9.0
[INFO] [stderr]     Checking neon-runtime v0.8.3
[INFO] [stderr]    Compiling neon v0.8.3
[INFO] [stderr]    Compiling serde_derive v1.0.127
[INFO] [stderr]    Compiling neon-macros v0.8.3
[INFO] [stderr]     Checking serde v1.0.127
[INFO] [stderr]  Documenting directory-tree v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[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 `directory-tree`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type cdylib --crate-name directory_tree src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern neon=/opt/rustwide/target/debug/deps/libneon-2e6e2e9f706c47d3.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-4ab2fd0aefd2fc60.rmeta --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-67b09d911de95b76.rmeta --cap-lints=warn --crate-version 0.0.1` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "dc0db2615d50656db224867a77719416bb2703003c051e7fe8f3b5c062b943ff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dc0db2615d50656db224867a77719416bb2703003c051e7fe8f3b5c062b943ff", kill_on_drop: false }`
[INFO] [stdout] dc0db2615d50656db224867a77719416bb2703003c051e7fe8f3b5c062b943ff
