[INFO] cloning repository https://github.com/Yos-K/immutable_list_rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Yos-K/immutable_list_rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYos-K%2Fimmutable_list_rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYos-K%2Fimmutable_list_rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 9f72ed3629b93317160352b4c5131223d11e633a
[INFO] checking Yos-K/immutable_list_rs against master#aa067fb984d36462548bb785da221bfaf38253f0 for pr-122470
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYos-K%2Fimmutable_list_rs" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Yos-K/immutable_list_rs on toolchain aa067fb984d36462548bb785da221bfaf38253f0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+aa067fb984d36462548bb785da221bfaf38253f0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Yos-K/immutable_list_rs
[INFO] finished tweaking git repo https://github.com/Yos-K/immutable_list_rs
[INFO] tweaked toml for git repo https://github.com/Yos-K/immutable_list_rs written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/Yos-K/immutable_list_rs 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" "+aa067fb984d36462548bb785da221bfaf38253f0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking Yos-K/immutable_list_rs against try#707d6562f55b55a7aab4ab3a904997116b358314 for pr-122470
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYos-K%2Fimmutable_list_rs" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Yos-K/immutable_list_rs on toolchain 707d6562f55b55a7aab4ab3a904997116b358314
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+707d6562f55b55a7aab4ab3a904997116b358314" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Yos-K/immutable_list_rs
[INFO] finished tweaking git repo https://github.com/Yos-K/immutable_list_rs
[INFO] tweaked toml for git repo https://github.com/Yos-K/immutable_list_rs written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/Yos-K/immutable_list_rs 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" "+707d6562f55b55a7aab4ab3a904997116b358314" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+707d6562f55b55a7aab4ab3a904997116b358314" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b1d6d92acc2fbc4f7676da7c2ab364c980640a9cb1eb515cb03876e174c75e50
[INFO] running `Command { std: "docker" "start" "-a" "b1d6d92acc2fbc4f7676da7c2ab364c980640a9cb1eb515cb03876e174c75e50", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b1d6d92acc2fbc4f7676da7c2ab364c980640a9cb1eb515cb03876e174c75e50", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b1d6d92acc2fbc4f7676da7c2ab364c980640a9cb1eb515cb03876e174c75e50", kill_on_drop: false }`
[INFO] [stdout] b1d6d92acc2fbc4f7676da7c2ab364c980640a9cb1eb515cb03876e174c75e50
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/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=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+707d6562f55b55a7aab4ab3a904997116b358314" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f732d4f35448131839ef89c6e3d47124aa815678337a30ef1ce71dafd56347bc
[INFO] running `Command { std: "docker" "start" "-a" "f732d4f35448131839ef89c6e3d47124aa815678337a30ef1ce71dafd56347bc", kill_on_drop: false }`
[INFO] [stderr]     Checking immutable_list_rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::ops::Index`
[INFO] [stdout]  --> src/lib.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ops::Index;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `Iterator` is imported redundantly
[INFO] [stdout]  --> src/lib.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::iter::Iterator;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/707d6562f55b55a7aab4ab3a904997116b358314/library/std/src/prelude/mod.rs:148:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `Iterator` is already defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::slice::Iter`
[INFO] [stdout]  --> src/lib.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::slice::Iter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `Iterator` is imported redundantly
[INFO] [stdout]  --> src/lib.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::iter::Iterator;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/707d6562f55b55a7aab4ab3a904997116b358314/library/std/src/prelude/mod.rs:148:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `Iterator` is already defined here
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::slice::Iter`
[INFO] [stdout]  --> src/lib.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::slice::Iter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `ImmutableList` is never constructed
[INFO] [stdout]  --> src/lib.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 | struct ImmutableList<T> {
[INFO] [stdout]   |        ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: multiple associated items are never used
[INFO] [stdout]   --> src/lib.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl<T> ImmutableList<T> where T: Clone {
[INFO] [stdout]    | --------------------------------------- associated items in this implementation
[INFO] [stdout] 13 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 17 |     pub fn len(&self) -> usize {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 27 |     pub fn index(&self, index: usize) -> Option<&T> {
[INFO] [stdout]    |            ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 35 |     pub fn is_empty(&self) -> bool {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 39 |     pub fn prepend(&self, value: T) -> Self {
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 56 |     pub fn append(&self, value: T) -> Self {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 75 |     pub fn iter(&self) -> IterList<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `IterList` is never constructed
[INFO] [stdout]   --> src/lib.rs:81:8
[INFO] [stdout]    |
[INFO] [stdout] 81 | struct IterList<'a, T>{
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::Index`
[INFO] [stdout]  --> src/lib.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::ops::Index;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.16s
[INFO] running `Command { std: "docker" "inspect" "f732d4f35448131839ef89c6e3d47124aa815678337a30ef1ce71dafd56347bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f732d4f35448131839ef89c6e3d47124aa815678337a30ef1ce71dafd56347bc", kill_on_drop: false }`
[INFO] [stdout] f732d4f35448131839ef89c6e3d47124aa815678337a30ef1ce71dafd56347bc