[INFO] cloning repository https://github.com/tiny-browserbook/exercise-rendering-tree
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tiny-browserbook/exercise-rendering-tree" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiny-browserbook%2Fexercise-rendering-tree", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiny-browserbook%2Fexercise-rendering-tree'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 52ba96b59bd81422a97a8caa975f4f04a7e8f63e
[INFO] checking tiny-browserbook/exercise-rendering-tree against master#1f12b9b0fdbe735968ac002792a720f0ba4faca6 for crater-rollup-uwu
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftiny-browserbook%2Fexercise-rendering-tree" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tiny-browserbook/exercise-rendering-tree on toolchain 1f12b9b0fdbe735968ac002792a720f0ba4faca6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/tiny-browserbook/exercise-rendering-tree
[INFO] finished tweaking git repo https://github.com/tiny-browserbook/exercise-rendering-tree
[INFO] tweaked toml for git repo https://github.com/tiny-browserbook/exercise-rendering-tree written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/tiny-browserbook/exercise-rendering-tree 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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 26a8207950e45b8e1e95e272f03b7a9a402c2d2f6a72c723376749c8f6993b49
[INFO] running `Command { std: "docker" "start" "-a" "26a8207950e45b8e1e95e272f03b7a9a402c2d2f6a72c723376749c8f6993b49", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "26a8207950e45b8e1e95e272f03b7a9a402c2d2f6a72c723376749c8f6993b49", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "26a8207950e45b8e1e95e272f03b7a9a402c2d2f6a72c723376749c8f6993b49", kill_on_drop: false }`
[INFO] [stdout] 26a8207950e45b8e1e95e272f03b7a9a402c2d2f6a72c723376749c8f6993b49
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 06b8c452c896f83c2ca3436c6c9887fde030992de665f4e3b9a10ac05f127b3f
[INFO] running `Command { std: "docker" "start" "-a" "06b8c452c896f83c2ca3436c6c9887fde030992de665f4e3b9a10ac05f127b3f", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]     Checking bytes v1.0.1
[INFO] [stderr]     Checking combine v4.5.2
[INFO] [stderr]     Checking exercise-rendering-tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `NodeType`
[INFO] [stdout]  --> src/css.rs:9:24
[INFO] [stdout]   |
[INFO] [stdout] 9 | use crate::dom::{Node, NodeType};
[INFO] [stdout]   |                        ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `NodeType`
[INFO] [stdout]  --> src/css.rs:9:24
[INFO] [stdout]   |
[INFO] [stdout] 9 | use crate::dom::{Node, NodeType};
[INFO] [stdout]   |                        ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `n`
[INFO] [stdout]   --> src/css.rs:66:27
[INFO] [stdout]    |
[INFO] [stdout] 66 |     pub fn matches(&self, n: &Box<Node>) -> bool {
[INFO] [stdout]    |                           ^ help: if this is intentional, prefix it with an underscore: `_n`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `node`
[INFO] [stdout]   --> src/style.rs:28:27
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub fn to_styled_node<'a>(node: &'a Box<Node>, stylesheet: &Stylesheet) -> Option<StyledNode<'a>> {
[INFO] [stdout]    |                           ^^^^ help: if this is intentional, prefix it with an underscore: `_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `stylesheet`
[INFO] [stdout]   --> src/style.rs:28:48
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub fn to_styled_node<'a>(node: &'a Box<Node>, stylesheet: &Stylesheet) -> Option<StyledNode<'a>> {
[INFO] [stdout]    |                                                ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_stylesheet`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `n`
[INFO] [stdout]   --> src/css.rs:66:27
[INFO] [stdout]    |
[INFO] [stdout] 66 |     pub fn matches(&self, n: &Box<Node>) -> bool {
[INFO] [stdout]    |                           ^ help: if this is intentional, prefix it with an underscore: `_n`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `node`
[INFO] [stdout]   --> src/style.rs:28:27
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub fn to_styled_node<'a>(node: &'a Box<Node>, stylesheet: &Stylesheet) -> Option<StyledNode<'a>> {
[INFO] [stdout]    |                           ^^^^ help: if this is intentional, prefix it with an underscore: `_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `stylesheet`
[INFO] [stdout]   --> src/style.rs:28:48
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub fn to_styled_node<'a>(node: &'a Box<Node>, stylesheet: &Stylesheet) -> Option<StyledNode<'a>> {
[INFO] [stdout]    |                                                ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_stylesheet`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.82s
[INFO] running `Command { std: "docker" "inspect" "06b8c452c896f83c2ca3436c6c9887fde030992de665f4e3b9a10ac05f127b3f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "06b8c452c896f83c2ca3436c6c9887fde030992de665f4e3b9a10ac05f127b3f", kill_on_drop: false }`
[INFO] [stdout] 06b8c452c896f83c2ca3436c6c9887fde030992de665f4e3b9a10ac05f127b3f