[INFO] fetching crate btree-slab 0.2.1...
[INFO] testing btree-slab-0.2.1 against 1.54.0 for beta-1.55-1
[INFO] extracting crate btree-slab 0.2.1 into /workspace/builds/worker-29/source
[INFO] validating manifest of crates.io crate btree-slab 0.2.1 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] started tweaking crates.io crate btree-slab 0.2.1
[INFO] finished tweaking crates.io crate btree-slab 0.2.1
[INFO] tweaked toml for crates.io crate btree-slab 0.2.1 written to /workspace/builds/worker-29/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] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded cc-traits v0.4.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-29/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-29/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] d98d0f5d8d0d29e0c27257d801cd4f9b8ded6088d495982a0d9121032bdbed31
[INFO] running `Command { std: "docker" "start" "-a" "d98d0f5d8d0d29e0c27257d801cd4f9b8ded6088d495982a0d9121032bdbed31", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d98d0f5d8d0d29e0c27257d801cd4f9b8ded6088d495982a0d9121032bdbed31", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d98d0f5d8d0d29e0c27257d801cd4f9b8ded6088d495982a0d9121032bdbed31", kill_on_drop: false }`
[INFO] [stdout] d98d0f5d8d0d29e0c27257d801cd4f9b8ded6088d495982a0d9121032bdbed31
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-29/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-29/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=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" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7865079a834565d0817e8f44c1d662d574e3841a699f984e2cd6a25a525a1982
[INFO] running `Command { std: "docker" "start" "-a" "7865079a834565d0817e8f44c1d662d574e3841a699f984e2cd6a25a525a1982", kill_on_drop: false }`
[INFO] [stderr]    Compiling slab v0.4.4
[INFO] [stderr]    Compiling smallvec v1.6.1
[INFO] [stderr]    Compiling cc-traits v0.4.0
[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/cc-traits-0.4.0/src/lib.rs:103:34
[INFO] [stdout]     |
[INFO] [stdout] 103 | #![cfg_attr(feature = "nightly", feature(trait_alias, generic_associated_types))]
[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 `cc-traits`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "7865079a834565d0817e8f44c1d662d574e3841a699f984e2cd6a25a525a1982", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7865079a834565d0817e8f44c1d662d574e3841a699f984e2cd6a25a525a1982", kill_on_drop: false }`
[INFO] [stdout] 7865079a834565d0817e8f44c1d662d574e3841a699f984e2cd6a25a525a1982
