[INFO] fetching crate fb_futures_01_ext 0.1.0...
[INFO] checking fb_futures_01_ext-0.1.0 against 1.95.0 for pr-155915
[INFO] extracting crate fb_futures_01_ext 0.1.0 into /workspace/builds/worker-2-tc1/source
[INFO] started tweaking crates.io crate fb_futures_01_ext 0.1.0
[INFO] finished tweaking crates.io crate fb_futures_01_ext 0.1.0
[INFO] tweaked toml for crates.io crate fb_futures_01_ext 0.1.0 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate fb_futures_01_ext 0.1.0 on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 87 packages to latest compatible versions
[INFO] [stderr]       Adding bytes v0.4.12 (available: v1.11.1)
[INFO] [stderr]       Adding futures v0.1.31 (available: v0.3.32)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "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 fb_cloned v0.1.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0495df5f7f2668d691a3c41eca30e14c7f12786d0fec9d0974f4327cde188313
[INFO] running `Command { std: "docker" "start" "-a" "0495df5f7f2668d691a3c41eca30e14c7f12786d0fec9d0974f4327cde188313", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0495df5f7f2668d691a3c41eca30e14c7f12786d0fec9d0974f4327cde188313", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0495df5f7f2668d691a3c41eca30e14c7f12786d0fec9d0974f4327cde188313", kill_on_drop: false }`
[INFO] [stdout] 0495df5f7f2668d691a3c41eca30e14c7f12786d0fec9d0974f4327cde188313
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d2cc7ac7a83426380a4d0ce07f94a909d047718a893b068506779b4b47bebe90
[INFO] running `Command { std: "docker" "start" "-a" "d2cc7ac7a83426380a4d0ce07f94a909d047718a893b068506779b4b47bebe90", kill_on_drop: false }`
[INFO] [stderr]     Checking futures v0.1.31
[INFO] [stderr]    Compiling serde v1.0.228
[INFO] [stderr]     Checking regex-syntax v0.8.10
[INFO] [stderr]    Compiling getrandom v0.4.2
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking rand_core v0.10.1
[INFO] [stderr]     Checking fb_cloned v0.1.3
[INFO] [stderr]     Checking assert_matches v1.5.0
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stderr]     Checking rand v0.10.1
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]     Checking regex-automata v0.4.14
[INFO] [stderr]     Checking tokio-io v0.1.13
[INFO] [stderr]     Checking fb_futures_01_ext v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:11:1
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![feature(never_type)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `fb_futures_01_ext` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "d2cc7ac7a83426380a4d0ce07f94a909d047718a893b068506779b4b47bebe90", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d2cc7ac7a83426380a4d0ce07f94a909d047718a893b068506779b4b47bebe90", kill_on_drop: false }`
[INFO] [stdout] d2cc7ac7a83426380a4d0ce07f94a909d047718a893b068506779b4b47bebe90
