[INFO] fetching crate perfcnt 0.7.1...
[INFO] documenting perfcnt-0.7.1 against 1.54.0 for beta-1.55-rustdoc-1
[INFO] extracting crate perfcnt 0.7.1 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate perfcnt 0.7.1 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] removed /workspace/builds/worker-9/source/rust-toolchain
[INFO] started tweaking crates.io crate perfcnt 0.7.1
[INFO] finished tweaking crates.io crate perfcnt 0.7.1
[INFO] tweaked toml for crates.io crate perfcnt 0.7.1 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate crates.io crate perfcnt 0.7.1 already has a lockfile, it will not be regenerated
[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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded raw-cpuid v9.0.0
[INFO] [stderr]   Downloaded mmap v0.1.1
[INFO] [stderr]   Downloaded x86 v0.37.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 5e02b1f8757f896750559a902e8b02961d324599afbb632421048d37ee673e74
[INFO] running `Command { std: "docker" "start" "-a" "5e02b1f8757f896750559a902e8b02961d324599afbb632421048d37ee673e74", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5e02b1f8757f896750559a902e8b02961d324599afbb632421048d37ee673e74", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5e02b1f8757f896750559a902e8b02961d324599afbb632421048d37ee673e74", kill_on_drop: false }`
[INFO] [stdout] 5e02b1f8757f896750559a902e8b02961d324599afbb632421048d37ee673e74
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] 52bd5d2c5c560badf07f0ebcb6541b19bb45d02e82d2555451fac1221cc1f0dd
[INFO] running `Command { std: "docker" "start" "-a" "52bd5d2c5c560badf07f0ebcb6541b19bb45d02e82d2555451fac1221cc1f0dd", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.71
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling serde v1.0.112
[INFO] [stderr]    Compiling ppv-lite86 v0.2.10
[INFO] [stderr]    Compiling siphasher v0.3.3
[INFO] [stderr]    Compiling serde_json v1.0.64
[INFO] [stderr]    Compiling itoa v0.4.6
[INFO] [stderr]    Compiling version_check v0.1.5
[INFO] [stderr]     Checking remove_dir_all v0.5.3
[INFO] [stderr]     Checking bit_field v0.10.1
[INFO] [stderr]     Checking libc v0.1.12
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]     Checking raw-cpuid v9.0.0
[INFO] [stderr]    Compiling phf_shared v0.8.0
[INFO] [stderr]     Checking phf v0.8.0
[INFO] [stderr]    Compiling nom v4.2.3
[INFO] [stderr]    Compiling regex-automata v0.1.9
[INFO] [stderr]    Compiling csv-core v0.1.10
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_pcg v0.2.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]     Checking tempdir v0.3.7
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]     Checking mmap v0.1.1
[INFO] [stderr]    Compiling phf_generator v0.8.0
[INFO] [stderr]    Compiling phf_codegen v0.8.0
[INFO] [stderr]    Compiling bstr v0.2.13
[INFO] [stderr]    Compiling csv v1.1.6
[INFO] [stderr]    Compiling x86 v0.37.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/x86-0.37.0/src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(llvm_asm, core_intrinsics)]
[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 compile `x86`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "52bd5d2c5c560badf07f0ebcb6541b19bb45d02e82d2555451fac1221cc1f0dd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52bd5d2c5c560badf07f0ebcb6541b19bb45d02e82d2555451fac1221cc1f0dd", kill_on_drop: false }`
[INFO] [stdout] 52bd5d2c5c560badf07f0ebcb6541b19bb45d02e82d2555451fac1221cc1f0dd
