[INFO] cloning repository https://github.com/hpp-playground/rust-playground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/hpp-playground/rust-playground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhpp-playground%2Frust-playground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhpp-playground%2Frust-playground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 26dc94c579620f6222d2f48f2054150f4cabbb43
[INFO] checking hpp-playground/rust-playground against master#5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhpp-playground%2Frust-playground" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/hpp-playground/rust-playground on toolchain 5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/hpp-playground/rust-playground
[INFO] finished tweaking git repo https://github.com/hpp-playground/rust-playground
[INFO] tweaked toml for git repo https://github.com/hpp-playground/rust-playground written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/hpp-playground/rust-playground already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ce199f6f66c45761c1ce436c09e4f9da7834b29babc38b7f9174a8d7f278b9e2
[INFO] running `Command { std: "docker" "start" "-a" "ce199f6f66c45761c1ce436c09e4f9da7834b29babc38b7f9174a8d7f278b9e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ce199f6f66c45761c1ce436c09e4f9da7834b29babc38b7f9174a8d7f278b9e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ce199f6f66c45761c1ce436c09e4f9da7834b29babc38b7f9174a8d7f278b9e2", kill_on_drop: false }`
[INFO] [stdout] ce199f6f66c45761c1ce436c09e4f9da7834b29babc38b7f9174a8d7f278b9e2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f229e5cec02cf4f9fac1d4cb5ef764cf35bfd88ef6e7ee9b7933cec448391239
[INFO] running `Command { std: "docker" "start" "-a" "f229e5cec02cf4f9fac1d4cb5ef764cf35bfd88ef6e7ee9b7933cec448391239", kill_on_drop: false }`
[INFO] [stderr]     Checking either v1.6.0
[INFO] [stderr]     Checking itertools v0.9.0
[INFO] [stderr]     Checking rust-playground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::collections::binary_heap::Iter`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::collections::binary_heap::Iter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/bin/iterator-learning.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |     let b: std::slice::Iter<i32> = a.iter();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Leaf`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     Leaf(Item),
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Children`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 |     Children(Vec<Node<Item>>),
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `traverse`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:9:8
[INFO] [stdout]   |
[INFO] [stdout] 9 |     fn traverse(&self, f: impl Fn(&It)) {
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::binary_heap::Iter`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::collections::binary_heap::Iter;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/bin/iterator-learning.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |     let b: std::slice::Iter<i32> = a.iter();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `traverse`
[INFO] [stdout]  --> src/bin/iterator-learning.rs:9:8
[INFO] [stdout]   |
[INFO] [stdout] 9 |     fn traverse(&self, f: impl Fn(&It)) {
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.83s
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "f229e5cec02cf4f9fac1d4cb5ef764cf35bfd88ef6e7ee9b7933cec448391239", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f229e5cec02cf4f9fac1d4cb5ef764cf35bfd88ef6e7ee9b7933cec448391239", kill_on_drop: false }`
[INFO] [stdout] f229e5cec02cf4f9fac1d4cb5ef764cf35bfd88ef6e7ee9b7933cec448391239