[INFO] fetching crate superset_map 0.3.4...
[INFO] testing superset_map-0.3.4 against 1.90.0 for beta-1.91-3
[INFO] extracting crate superset_map 0.3.4 into /workspace/builds/worker-4-tc1/source
[INFO] removed /workspace/builds/worker-4-tc1/source/rust-toolchain.toml
[INFO] started tweaking crates.io crate superset_map 0.3.4
[INFO] finished tweaking crates.io crate superset_map 0.3.4
[INFO] tweaked toml for crates.io crate superset_map 0.3.4 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate superset_map 0.3.4 on toolchain 1.90.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate superset_map 0.3.4 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded zfc v0.4.4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d51d498d81a0d4d63bfc98d56a0d6b14798832c661e2071c0814310d773876a7
[INFO] running `Command { std: "docker" "start" "-a" "d51d498d81a0d4d63bfc98d56a0d6b14798832c661e2071c0814310d773876a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d51d498d81a0d4d63bfc98d56a0d6b14798832c661e2071c0814310d773876a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d51d498d81a0d4d63bfc98d56a0d6b14798832c661e2071c0814310d773876a7", kill_on_drop: false }`
[INFO] [stdout] d51d498d81a0d4d63bfc98d56a0d6b14798832c661e2071c0814310d773876a7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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=warn" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a31a41484af5c3b8bc8c6a8a3836f7a96133e00628d264c30d40f66912093f8f
[INFO] running `Command { std: "docker" "start" "-a" "a31a41484af5c3b8bc8c6a8a3836f7a96133e00628d264c30d40f66912093f8f", kill_on_drop: false }`
[INFO] [stderr]    Compiling num-integer v0.1.46
[INFO] [stderr]    Compiling num-bigint v0.4.6
[INFO] [stderr]    Compiling zfc v0.4.4
[INFO] [stderr]    Compiling superset_map v0.3.4 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:138:1
[INFO] [stdout]     |
[INFO] [stdout] 138 | #![feature(btree_cursors)]
[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 `superset_map` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "a31a41484af5c3b8bc8c6a8a3836f7a96133e00628d264c30d40f66912093f8f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a31a41484af5c3b8bc8c6a8a3836f7a96133e00628d264c30d40f66912093f8f", kill_on_drop: false }`
[INFO] [stdout] a31a41484af5c3b8bc8c6a8a3836f7a96133e00628d264c30d40f66912093f8f