[INFO] fetching crate rustep 0.1.2...
[INFO] documenting rustep-0.1.2 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate rustep 0.1.2 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate rustep 0.1.2 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 rustep 0.1.2
[INFO] finished tweaking crates.io crate rustep 0.1.2
[INFO] tweaked toml for crates.io crate rustep 0.1.2 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--manifest-path" "Cargo.toml", 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]  Downloading crates ...
[INFO] [stderr]   Downloaded clang-sys v0.22.0
[INFO] [stderr]   Downloaded bindgen v0.33.2
[INFO] [stderr]   Downloaded enumflags_derive v0.4.1
[INFO] [stderr]   Downloaded enumflags v0.3.2
[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] d30053df5284f057d805fee76e0c530a74de774ed21f325a13aac8b9bf5cacae
[INFO] running `Command { std: "docker" "start" "-a" "d30053df5284f057d805fee76e0c530a74de774ed21f325a13aac8b9bf5cacae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d30053df5284f057d805fee76e0c530a74de774ed21f325a13aac8b9bf5cacae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d30053df5284f057d805fee76e0c530a74de774ed21f325a13aac8b9bf5cacae", kill_on_drop: false }`
[INFO] [stdout] d30053df5284f057d805fee76e0c530a74de774ed21f325a13aac8b9bf5cacae
[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] 1bc074f6eedb8f52eb9321bc0147f30176e5ad78f34dc976edd507e2c734ff9a
[INFO] running `Command { std: "docker" "start" "-a" "1bc074f6eedb8f52eb9321bc0147f30176e5ad78f34dc976edd507e2c734ff9a", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.1.0
[INFO] [stderr]    Compiling libc v0.2.126
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.39
[INFO] [stderr]    Compiling unicode-ident v1.0.0
[INFO] [stderr]    Compiling memchr v2.5.0
[INFO] [stderr]    Compiling syn v1.0.95
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]     Checking rustc-serialize v0.3.24
[INFO] [stderr]    Compiling cc v1.0.73
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]     Checking adler v1.0.2
[INFO] [stderr]     Checking gimli v0.26.1
[INFO] [stderr]    Compiling unicode-xid v0.2.3
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking rustc-demangle v0.1.21
[INFO] [stderr]    Compiling num-derive v0.2.5
[INFO] [stderr]     Checking enumflags v0.3.2
[INFO] [stderr]    Compiling proc-macro2 v0.2.3
[INFO] [stderr]     Checking miniz_oxide v0.5.1
[INFO] [stderr]    Compiling num-traits v0.2.15
[INFO] [stderr]    Compiling num-integer v0.1.45
[INFO] [stderr]    Compiling num-iter v0.1.43
[INFO] [stderr]    Compiling quote v0.4.2
[INFO] [stderr]    Compiling syn v0.12.15
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]     Checking object v0.28.4
[INFO] [stderr]    Compiling backtrace v0.3.65
[INFO] [stderr]    Compiling quote v1.0.18
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking memchr v1.0.2
[INFO] [stderr]     Checking nom v3.2.1
[INFO] [stderr]     Checking addr2line v0.17.0
[INFO] [stderr]     Checking num-complex v0.1.43
[INFO] [stderr]     Checking num-bigint v0.1.44
[INFO] [stderr]    Compiling synstructure v0.12.6
[INFO] [stderr]    Compiling enumflags_derive v0.4.1
[INFO] [stderr]     Checking num-rational v0.1.42
[INFO] [stderr]     Checking num v0.1.42
[INFO] [stderr]     Checking failure v0.1.8
[INFO] [stderr]  Documenting rustep v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:49:12
[INFO] [stdout]    |
[INFO] [stdout] 49 | #![feature(try_from)]
[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 `rustep`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name rustep src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=4f1ba832f389fa1f -L dependency=/opt/rustwide/target/debug/deps --extern enumflags=/opt/rustwide/target/debug/deps/libenumflags-9d54dd0f0122ec56.rmeta --extern enumflags_derive=/opt/rustwide/target/debug/deps/libenumflags_derive-e1866fc40f3e2fcb.so --extern failure=/opt/rustwide/target/debug/deps/libfailure-6cb132f99b91f1b2.rmeta --extern nom=/opt/rustwide/target/debug/deps/libnom-bb153aed95f65c5a.rmeta --extern num=/opt/rustwide/target/debug/deps/libnum-3438e0eb9e736531.rmeta --extern num_derive=/opt/rustwide/target/debug/deps/libnum_derive-e97f7eecb109fbd7.so --extern num_traits=/opt/rustwide/target/debug/deps/libnum_traits-9d0fb7f65d2860a4.rmeta --cap-lints=warn --crate-version 0.1.2` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "1bc074f6eedb8f52eb9321bc0147f30176e5ad78f34dc976edd507e2c734ff9a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1bc074f6eedb8f52eb9321bc0147f30176e5ad78f34dc976edd507e2c734ff9a", kill_on_drop: false }`
[INFO] [stdout] 1bc074f6eedb8f52eb9321bc0147f30176e5ad78f34dc976edd507e2c734ff9a