[INFO] crate avl_tree 0.2.0 is already in cache
[INFO] testing avl_tree-0.2.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate avl_tree 0.2.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate avl_tree 0.2.0 on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate avl_tree 0.2.0
[INFO] finished tweaking crates.io crate avl_tree 0.2.0
[INFO] tweaked toml for crates.io crate avl_tree 0.2.0 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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=warn" "-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" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 735622fad7c13f921644f8a207fc229920ba9fdfd7f7af2ca018fccbe4496a68
[INFO] running `"docker" "start" "-a" "735622fad7c13f921644f8a207fc229920ba9fdfd7f7af2ca018fccbe4496a68"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling syn v1.0.30
[INFO] [stderr]    Compiling standback v0.2.8
[INFO] [stderr]    Compiling time v0.2.16
[INFO] [stderr]    Compiling time-macros-impl v0.1.1
[INFO] [stderr]    Compiling time-macros v0.1.0
[INFO] [stderr]    Compiling avl_tree v0.2.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(test)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![feature(collections_bound)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:5:1
[INFO] [stderr]   |
[INFO] [stderr] 5 | #![feature(rand)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary parentheses around function argument
[INFO] [stderr]    --> src/node.rs:252:20
[INFO] [stderr]     |
[INFO] [stderr] 252 |         t = insert((x as u64),1337+x-1,t)
[INFO] [stderr]     |                    ^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `max`, `min`, `to_string`
[INFO] [stderr]  --> src/tree.rs:5:33
[INFO] [stderr]   |
[INFO] [stderr] 5 | use node::{insert,delete,search,min,max,is_avl_tree, to_string, min_pair, max_pair};
[INFO] [stderr]   |                                 ^^^ ^^^              ^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors; 2 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `avl_tree`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "735622fad7c13f921644f8a207fc229920ba9fdfd7f7af2ca018fccbe4496a68"`
[INFO] running `"docker" "rm" "-f" "735622fad7c13f921644f8a207fc229920ba9fdfd7f7af2ca018fccbe4496a68"`
[INFO] [stdout] 735622fad7c13f921644f8a207fc229920ba9fdfd7f7af2ca018fccbe4496a68