[INFO] fetching crate optimal-core 0.0.0...
[INFO] checking optimal-core-0.0.0 against 1.95.0 for pr-155915
[INFO] extracting crate optimal-core 0.0.0 into /workspace/builds/worker-1-tc1/source
[INFO] started tweaking crates.io crate optimal-core 0.0.0
[INFO] finished tweaking crates.io crate optimal-core 0.0.0
[INFO] tweaked toml for crates.io crate optimal-core 0.0.0 written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate optimal-core 0.0.0 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]     Updating crates.io index
[INFO] [stderr]      Locking 16 packages to latest compatible versions
[INFO] [stderr]       Adding blanket v0.3.0 (available: v0.4.0)
[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]  Downloading crates ...
[INFO] [stderr]   Downloaded replace_with v0.1.8
[INFO] [stderr]   Downloaded blanket v0.3.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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] d3160018070cbf56921fa458ea0c0c65d93af04503a6e7e94bc140317a9ac7ee
[INFO] running `Command { std: "docker" "start" "-a" "d3160018070cbf56921fa458ea0c0c65d93af04503a6e7e94bc140317a9ac7ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d3160018070cbf56921fa458ea0c0c65d93af04503a6e7e94bc140317a9ac7ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d3160018070cbf56921fa458ea0c0c65d93af04503a6e7e94bc140317a9ac7ee", kill_on_drop: false }`
[INFO] [stdout] d3160018070cbf56921fa458ea0c0c65d93af04503a6e7e94bc140317a9ac7ee
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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] 63fb2a9f31a62d28e6cf404efb5172a1918a1604ce6a3590e6d56115ec9a0fec
[INFO] running `Command { std: "docker" "start" "-a" "63fb2a9f31a62d28e6cf404efb5172a1918a1604ce6a3590e6d56115ec9a0fec", kill_on_drop: false }`
[INFO] [stderr]     Checking streaming-iterator v0.1.9
[INFO] [stderr]     Checking replace_with v0.1.8
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stderr]    Compiling serde_derive v1.0.228
[INFO] [stderr]    Compiling blanket v0.3.0
[INFO] [stderr]     Checking optimal-core v0.0.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking serde v1.0.228
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(test, feature(unboxed_closures))]
[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 `optimal-core` (lib test) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "63fb2a9f31a62d28e6cf404efb5172a1918a1604ce6a3590e6d56115ec9a0fec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "63fb2a9f31a62d28e6cf404efb5172a1918a1604ce6a3590e6d56115ec9a0fec", kill_on_drop: false }`
[INFO] [stdout] 63fb2a9f31a62d28e6cf404efb5172a1918a1604ce6a3590e6d56115ec9a0fec
