[INFO] updating cached repository https://github.com/raiker/persistent-rope
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/mnt/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 7f638488c32998e1683a0a3ba8de4846c9a5dee7
[INFO] checking raiker/persistent-rope against master#c9edc02e8320a9e5799d185910ece7d491f524e6 for pr-64398
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fraiker%2Fpersistent-rope" "work/builds/worker-2/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/raiker/persistent-rope on toolchain c9edc02e8320a9e5799d185910ece7d491f524e6-alt
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/raiker/persistent-rope
[INFO] finished tweaking git repo https://github.com/raiker/persistent-rope
[INFO] tweaked toml for git repo https://github.com/raiker/persistent-rope written to work/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/raiker/persistent-rope already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/cargo-home/bin/cargo" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/mnt/big/crater/work/builds/worker-2/source:/opt/rustwide/workdir:ro,Z" "-v" "/mnt/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+c9edc02e8320a9e5799d185910ece7d491f524e6-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 205ccf4e8fe98568c181c1e4fe05873acbeebd7f37b681461cb8a4c18563218e
[INFO] running `"docker" "start" "-a" "205ccf4e8fe98568c181c1e4fe05873acbeebd7f37b681461cb8a4c18563218e"`
[INFO] [stderr]     Checking persistent-rope v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `parent`
[INFO] [stderr]    --> src/main.rs:141:69
[INFO] [stderr]     |
[INFO] [stderr] 141 |     fn rec_insert(key: K, val: V, current: &Rc<Option<TreeNode<K,V>>>, parent: Option<&Rc<Option<TreeNode<K,V>>>>) -> InsertionResultRecursion<K,V>{
[INFO] [stderr]     |                                                                        ^^^^^^ help: consider prefixing with an underscore: `_parent`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `RcSliceableString`
[INFO] [stderr]  --> src/rcstr.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | pub struct RcSliceableString {
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/rcstr.rs:10:2
[INFO] [stderr]    |
[INFO] [stderr] 10 |     pub fn new(s: String) -> RcSliceableString {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `slice`
[INFO] [stderr]   --> src/rcstr.rs:19:2
[INFO] [stderr]    |
[INFO] [stderr] 19 |     pub fn slice(&self, start: usize, len: usize) -> RcSliceableString {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `as_str`
[INFO] [stderr]   --> src/rcstr.rs:34:2
[INFO] [stderr]    |
[INFO] [stderr] 34 |     pub fn as_str(&self) -> &str {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `parent`
[INFO] [stderr]    --> src/main.rs:141:69
[INFO] [stderr]     |
[INFO] [stderr] 141 |     fn rec_insert(key: K, val: V, current: &Rc<Option<TreeNode<K,V>>>, parent: Option<&Rc<Option<TreeNode<K,V>>>>) -> InsertionResultRecursion<K,V>{
[INFO] [stderr]     |                                                                        ^^^^^^ help: consider prefixing with an underscore: `_parent`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.64s
[INFO] running `"docker" "inspect" "205ccf4e8fe98568c181c1e4fe05873acbeebd7f37b681461cb8a4c18563218e"`
[INFO] running `"docker" "rm" "-f" "205ccf4e8fe98568c181c1e4fe05873acbeebd7f37b681461cb8a4c18563218e"`
[INFO] [stdout] 205ccf4e8fe98568c181c1e4fe05873acbeebd7f37b681461cb8a4c18563218e