[INFO] cloning repository https://github.com/vitocchi/rust-tree
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/vitocchi/rust-tree" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvitocchi%2Frust-tree", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvitocchi%2Frust-tree'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5b45d6e8791183f5d4767ec6384f8ea62a437e65
[INFO] checking vitocchi/rust-tree against try#a7a572ce3edd6d476191fbfe92c9c1986e009b34 for pr-87190-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvitocchi%2Frust-tree" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/vitocchi/rust-tree on toolchain a7a572ce3edd6d476191fbfe92c9c1986e009b34
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a7a572ce3edd6d476191fbfe92c9c1986e009b34" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/vitocchi/rust-tree
[INFO] finished tweaking git repo https://github.com/vitocchi/rust-tree
[INFO] tweaked toml for git repo https://github.com/vitocchi/rust-tree written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/vitocchi/rust-tree already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a7a572ce3edd6d476191fbfe92c9c1986e009b34" "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-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "+a7a572ce3edd6d476191fbfe92c9c1986e009b34" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5ffebd0132bcff3bd014597aca062182f2f63341bd5f4433ac419a319ef1393b
[INFO] running `Command { std: "docker" "start" "-a" "5ffebd0132bcff3bd014597aca062182f2f63341bd5f4433ac419a319ef1393b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5ffebd0132bcff3bd014597aca062182f2f63341bd5f4433ac419a319ef1393b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5ffebd0132bcff3bd014597aca062182f2f63341bd5f4433ac419a319ef1393b", kill_on_drop: false }`
[INFO] [stdout] 5ffebd0132bcff3bd014597aca062182f2f63341bd5f4433ac419a319ef1393b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "+a7a572ce3edd6d476191fbfe92c9c1986e009b34" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 86e512c78ac633733ad8860c78013388dda7b204d1a483c13541dfea52db5522
[INFO] running `Command { std: "docker" "start" "-a" "86e512c78ac633733ad8860c78013388dda7b204d1a483c13541dfea52db5522", kill_on_drop: false }`
[INFO] [stderr] Copying to /tmp/fixit
[INFO] [stderr] Running `cargo fix --edition`
[INFO] [stderr]     Checking rustree v0.1.0 (/tmp/fixit)
[INFO] [stderr]    Migrating src/lib.rs from 2018 edition to 2021
[INFO] [stderr]        Fixed src/tree.rs (1 fix)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:17:13
[INFO] [stdout]    |
[INFO] [stdout] 17 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |             write!(f, " ");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |         writeln!(f, "{}", self.value);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `writeln` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:24:13
[INFO] [stdout]    |
[INFO] [stdout] 24 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:17:13
[INFO] [stdout]    |
[INFO] [stdout] 17 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |             write!(f, " ");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |         writeln!(f, "{}", self.value);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `writeln` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:24:13
[INFO] [stdout]    |
[INFO] [stdout] 24 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Migrating src/main.rs from 2018 edition to 2021
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 |     root.add_left_child(build_node(2));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     root.add_right_child(build_node(3));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     rroot.add_right_child(root);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     rroot.add_left_child(build_node(5));
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 |     root.add_left_child(build_node(2));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     root.add_right_child(build_node(3));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     rroot.add_right_child(root);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     rroot.add_left_child(build_node(5));
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.04s
[INFO] [stderr] Running `cargo check` to verify 2021
[INFO] [stderr]     Checking rustree v0.1.0 (/tmp/fixit)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:17:13
[INFO] [stdout]    |
[INFO] [stdout] 17 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |             write!(f, " ");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |         writeln!(f, "{}", self.value);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `writeln` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:24:13
[INFO] [stdout]    |
[INFO] [stdout] 24 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:17:13
[INFO] [stdout]    |
[INFO] [stdout] 17 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |             write!(f, " ");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |         writeln!(f, "{}", self.value);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `writeln` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/tree.rs:24:13
[INFO] [stdout]    |
[INFO] [stdout] 24 |             child.write_tree(f, depth + 1);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 |     root.add_left_child(build_node(2));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     root.add_right_child(build_node(3));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     rroot.add_right_child(root);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     rroot.add_left_child(build_node(5));
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 |     root.add_left_child(build_node(2));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     root.add_right_child(build_node(3));
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     rroot.add_right_child(root);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     rroot.add_left_child(build_node(5));
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.40s
[INFO] running `Command { std: "docker" "inspect" "86e512c78ac633733ad8860c78013388dda7b204d1a483c13541dfea52db5522", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "86e512c78ac633733ad8860c78013388dda7b204d1a483c13541dfea52db5522", kill_on_drop: false }`
[INFO] [stdout] 86e512c78ac633733ad8860c78013388dda7b204d1a483c13541dfea52db5522