[INFO] crate concurrent-hashmap 0.2.2 is already in cache
[INFO] checking concurrent-hashmap-0.2.2 against master#45d050cde277b22a755847338f2acc2c7b834141 for pr-71393
[INFO] extracting crate concurrent-hashmap 0.2.2 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate concurrent-hashmap 0.2.2 on toolchain 45d050cde277b22a755847338f2acc2c7b834141
[INFO] running `"/workspace/cargo-home/bin/cargo" "+45d050cde277b22a755847338f2acc2c7b834141" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate concurrent-hashmap 0.2.2
[INFO] finished tweaking crates.io crate concurrent-hashmap 0.2.2
[INFO] tweaked toml for crates.io crate concurrent-hashmap 0.2.2 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+45d050cde277b22a755847338f2acc2c7b834141" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+45d050cde277b22a755847338f2acc2c7b834141" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+45d050cde277b22a755847338f2acc2c7b834141" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 2fd922fd6172f6c425a8ccd679cf06dc9ffb8aef497e7ae381de4de78560ccf4
[INFO] running `"docker" "start" "-a" "2fd922fd6172f6c425a8ccd679cf06dc9ffb8aef497e7ae381de4de78560ccf4"`
[INFO] [stderr]     Checking spin v0.4.8
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking concurrent-hashmap v0.2.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking rand v0.3.23
[INFO] [stderr] error[E0635]: unknown feature `step_by`
[INFO] [stderr]  --> examples/wordcount.rs:1:12
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(step_by)]
[INFO] [stderr]   |            ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0635`.
[INFO] [stderr] error: could not compile `concurrent-hashmap`.
[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] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/map.rs:537:13
[INFO] [stderr]     |
[INFO] [stderr] 537 |         let mut e = map.find_mut(&1).unwrap().get();
[INFO] [stderr]     |             ----^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/map.rs:561:21
[INFO] [stderr]     |
[INFO] [stderr] 561 |                 let mut e = tl_map.find_mut(&i).unwrap().get();
[INFO] [stderr]     |                     ----^
[INFO] [stderr]     |                     |
[INFO] [stderr]     |                     help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: 2 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "2fd922fd6172f6c425a8ccd679cf06dc9ffb8aef497e7ae381de4de78560ccf4"`
[INFO] running `"docker" "rm" "-f" "2fd922fd6172f6c425a8ccd679cf06dc9ffb8aef497e7ae381de4de78560ccf4"`
[INFO] [stdout] 2fd922fd6172f6c425a8ccd679cf06dc9ffb8aef497e7ae381de4de78560ccf4