[INFO] fetching crate seed_style_preview 0.1.8...
[INFO] testing seed_style_preview-0.1.8 against 1.49.0 for beta-1.50-1
[INFO] extracting crate seed_style_preview 0.1.8 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate seed_style_preview 0.1.8 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate seed_style_preview 0.1.8
[INFO] finished tweaking crates.io crate seed_style_preview 0.1.8
[INFO] tweaked toml for crates.io crate seed_style_preview 0.1.8 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] acfb50fde655d0f7259479237a93b4d61e59b6df013372b9fcca0201a3e88ed1
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "acfb50fde655d0f7259479237a93b4d61e59b6df013372b9fcca0201a3e88ed1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "acfb50fde655d0f7259479237a93b4d61e59b6df013372b9fcca0201a3e88ed1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "acfb50fde655d0f7259479237a93b4d61e59b6df013372b9fcca0201a3e88ed1", kill_on_drop: false }`
[INFO] [stdout] acfb50fde655d0f7259479237a93b4d61e59b6df013372b9fcca0201a3e88ed1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fac0598588fb7ce7d894fc41771c1cadc72b45049add176d81a299e2e15d90f7
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "fac0598588fb7ce7d894fc41771c1cadc72b45049add176d81a299e2e15d90f7", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.69
[INFO] [stderr]    Compiling bumpalo v3.4.0
[INFO] [stderr]    Compiling wasm-bindgen v0.2.69
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling strsim v0.9.3
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling scopeguard v1.1.0
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling version_check v0.1.5
[INFO] [stderr]    Compiling pulldown-cmark v0.7.2
[INFO] [stderr]    Compiling traitobject v0.1.0
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling anymap v0.12.1
[INFO] [stderr]    Compiling slotmap v0.4.0
[INFO] [stderr]    Compiling enclose v1.1.8
[INFO] [stderr]    Compiling objekt v0.1.2
[INFO] [stderr]    Compiling eager v0.1.0
[INFO] [stderr]    Compiling harsh v0.1.7
[INFO] [stderr]    Compiling proc-macro-error-attr v0.4.12
[INFO] [stderr]    Compiling proc-macro-error v0.4.12
[INFO] [stderr]    Compiling seed v0.7.0
[INFO] [stderr]    Compiling indexmap v1.6.1
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling owning_ref v0.4.1
[INFO] [stderr]    Compiling getopts v0.2.21
[INFO] [stderr]    Compiling unsafe-any v0.4.2
[INFO] [stderr]    Compiling heck v0.3.2
[INFO] [stderr]    Compiling typemap v0.3.3
[INFO] [stderr]    Compiling dbg v1.0.4
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling rand_pcg v0.2.1
[INFO] [stderr]    Compiling rand v0.7.3
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling ordered-float v1.1.1
[INFO] [stderr]    Compiling wasm-bindgen-backend v0.2.69
[INFO] [stderr]    Compiling syn-mid v0.5.2
[INFO] [stderr]    Compiling darling_core v0.10.2
[INFO] [stderr]    Compiling wasm-bindgen-macro-support v0.2.69
[INFO] [stderr]    Compiling objekt-clonable-impl v0.2.2
[INFO] [stderr]    Compiling serde_derive v1.0.118
[INFO] [stderr]    Compiling pin-project-internal v1.0.2
[INFO] [stderr]    Compiling futures-macro v0.3.8
[INFO] [stderr]    Compiling time-macros-impl v0.1.1
[INFO] [stderr]    Compiling topo-macro v0.9.0
[INFO] [stderr]    Compiling derive_more v0.99.11
[INFO] [stderr]    Compiling darling_macro v0.10.2
[INFO] [stderr]    Compiling objekt-clonable v0.2.2
[INFO] [stderr]    Compiling wasm-bindgen-macro v0.2.69
[INFO] [stderr]    Compiling darling v0.10.2
[INFO] [stderr]    Compiling time-macros v0.1.1
[INFO] [stderr]    Compiling time v0.2.23
[INFO] [stderr]    Compiling illicit-macro v0.9.0
[INFO] [stderr]    Compiling cookie v0.13.3
[INFO] [stderr]    Compiling pin-project v1.0.2
[INFO] [stderr]    Compiling futures-util v0.3.8
[INFO] [stderr]    Compiling illicit v0.9.2
[INFO] [stderr]    Compiling topo v0.9.4
[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/topo-0.9.4/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(track_caller)]
[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 `topo`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "fac0598588fb7ce7d894fc41771c1cadc72b45049add176d81a299e2e15d90f7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fac0598588fb7ce7d894fc41771c1cadc72b45049add176d81a299e2e15d90f7", kill_on_drop: false }`
[INFO] [stdout] fac0598588fb7ce7d894fc41771c1cadc72b45049add176d81a299e2e15d90f7