[INFO] fetching crate loader-rs 0.7.0...
[INFO] documenting loader-rs-0.7.0 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate loader-rs 0.7.0 into /workspace/builds/worker-94/source
[INFO] validating manifest of crates.io crate loader-rs 0.7.0 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] removed /workspace/builds/worker-94/source/rust-toolchain
[INFO] started tweaking crates.io crate loader-rs 0.7.0
[INFO] finished tweaking crates.io crate loader-rs 0.7.0
[INFO] tweaked toml for crates.io crate loader-rs 0.7.0 written to /workspace/builds/worker-94/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-94/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-94/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] c74d0a308aadc899958a4f848d2c42148368dcb66404602469b4311efcc83be1
[INFO] running `Command { std: "docker" "start" "-a" "c74d0a308aadc899958a4f848d2c42148368dcb66404602469b4311efcc83be1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c74d0a308aadc899958a4f848d2c42148368dcb66404602469b4311efcc83be1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c74d0a308aadc899958a4f848d2c42148368dcb66404602469b4311efcc83be1", kill_on_drop: false }`
[INFO] [stdout] c74d0a308aadc899958a4f848d2c42148368dcb66404602469b4311efcc83be1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-94/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-94/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] 036fdf479b171c26e15cda188f84d2f5e46ff975bb98e88551991c985edec833
[INFO] running `Command { std: "docker" "start" "-a" "036fdf479b171c26e15cda188f84d2f5e46ff975bb98e88551991c985edec833", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.98
[INFO] [stderr]    Compiling proc-macro-hack v0.5.19
[INFO] [stderr]     Checking futures-sink v0.3.16
[INFO] [stderr]    Compiling futures-channel v0.3.16
[INFO] [stderr]    Compiling proc-macro-nested v0.1.7
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking fnv v1.0.7
[INFO] [stderr]     Checking bytes v0.5.6
[INFO] [stderr]     Checking futures-io v0.3.16
[INFO] [stderr]     Checking pin-project-lite v0.1.12
[INFO] [stderr]     Checking matches v0.1.8
[INFO] [stderr]     Checking foreign-types-shared v0.1.1
[INFO] [stderr]     Checking bytes v1.0.1
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling crc32fast v1.2.1
[INFO] [stderr]     Checking tinyvec_macros v0.1.0
[INFO] [stderr]    Compiling strsim v0.9.3
[INFO] [stderr]     Checking hashbrown v0.11.2
[INFO] [stderr]     Checking openssl-probe v0.1.4
[INFO] [stderr]     Checking try-lock v0.2.3
[INFO] [stderr]     Checking percent-encoding v2.1.0
[INFO] [stderr]     Checking httpdate v0.3.2
[INFO] [stderr]     Checking tower-service v0.3.1
[INFO] [stderr]    Compiling event-listener v2.5.1
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]     Checking mime v0.3.16
[INFO] [stderr]    Compiling cached_proc_macro_types v0.1.0
[INFO] [stderr]     Checking ipnet v2.3.1
[INFO] [stderr]     Checking strum v0.21.0
[INFO] [stderr]    Compiling futures-macro v0.3.16
[INFO] [stderr]    Compiling futures-util v0.3.16
[INFO] [stderr]    Compiling indexmap v1.7.0
[INFO] [stderr]     Checking instant v0.1.10
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]     Checking futures-task v0.3.16
[INFO] [stderr]     Checking unicode-bidi v0.3.5
[INFO] [stderr]     Checking lock_api v0.4.4
[INFO] [stderr]     Checking tracing v0.1.26
[INFO] [stderr]     Checking httparse v1.4.1
[INFO] [stderr]     Checking encoding_rs v0.8.28
[INFO] [stderr]    Compiling pin-project-internal v1.0.8
[INFO] [stderr]     Checking want v0.3.0
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[INFO] [stderr]    Compiling darling_core v0.10.2
[INFO] [stderr]     Checking foreign-types v0.3.2
[INFO] [stderr]     Checking form_urlencoded v1.0.1
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[INFO] [stderr]     Checking http v0.2.4
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking serde_urlencoded v0.7.0
[INFO] [stderr]    Compiling strum_macros v0.21.1
[INFO] [stderr]     Checking unicode-normalization v0.1.19
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[INFO] [stderr]    Compiling mime_guess v2.0.3
[INFO] [stderr]     Checking parking_lot v0.11.1
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking async-compression v0.3.8
[INFO] [stderr]     Checking openssl v0.10.35
[INFO] [stderr]     Checking idna v0.2.3
[INFO] [stderr]     Checking tokio v0.2.25
[INFO] [stderr]    Compiling darling_macro v0.10.2
[INFO] [stderr]     Checking http-body v0.3.1
[INFO] [stderr]     Checking pin-project v1.0.8
[INFO] [stderr]     Checking url v2.2.2
[INFO] [stderr]     Checking tracing-futures v0.2.5
[INFO] [stderr]     Checking native-tls v0.2.7
[INFO] [stderr]    Compiling darling v0.10.2
[INFO] [stderr]    Compiling cached_proc_macro v0.6.0
[INFO] [stderr]     Checking tokio-util v0.3.1
[INFO] [stderr]     Checking tokio-tls v0.3.1
[INFO] [stderr]     Checking h2 v0.2.7
[INFO] [stderr]     Checking futures-executor v0.3.16
[INFO] [stderr]     Checking futures v0.3.16
[INFO] [stderr]     Checking cached v0.24.0
[INFO] [stderr]     Checking hyper v0.13.10
[INFO] [stderr]     Checking hyper-tls v0.4.3
[INFO] [stderr]     Checking reqwest v0.10.10
[INFO] [stderr]  Documenting loader-rs 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:43:1
[INFO] [stdout]    |
[INFO] [stdout] 43 | #![feature(specialization)]
[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 `loader-rs`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name loader_rs src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern cached=/opt/rustwide/target/debug/deps/libcached-67a403d56a305e9b.rmeta --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-acd7d23482fe8b54.rmeta --extern parking_lot=/opt/rustwide/target/debug/deps/libparking_lot-1e0dd886fc2f2bbe.rmeta --extern reqwest=/opt/rustwide/target/debug/deps/libreqwest-d81b1ec8f6832ab1.rmeta --extern strum=/opt/rustwide/target/debug/deps/libstrum-a08f3cd804d5d373.rmeta --extern strum_macros=/opt/rustwide/target/debug/deps/libstrum_macros-438990b33a586628.so --extern url=/opt/rustwide/target/debug/deps/liburl-f6ffcc7df1261a72.rmeta --cap-lints=warn --crate-version 0.7.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "036fdf479b171c26e15cda188f84d2f5e46ff975bb98e88551991c985edec833", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "036fdf479b171c26e15cda188f84d2f5e46ff975bb98e88551991c985edec833", kill_on_drop: false }`
[INFO] [stdout] 036fdf479b171c26e15cda188f84d2f5e46ff975bb98e88551991c985edec833
