[INFO] cloning repository https://github.com/sergorl/merkle_hash_tree
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sergorl/merkle_hash_tree" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsergorl%2Fmerkle_hash_tree", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsergorl%2Fmerkle_hash_tree'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 27429dcf39c550bb473f4c7907ca5c3de4e5aacf
[INFO] testing sergorl/merkle_hash_tree against beta-2021-08-01 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsergorl%2Fmerkle_hash_tree" "/workspace/builds/worker-110/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-110/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sergorl/merkle_hash_tree on toolchain beta-2021-08-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sergorl/merkle_hash_tree
[INFO] finished tweaking git repo https://github.com/sergorl/merkle_hash_tree
[INFO] tweaked toml for git repo https://github.com/sergorl/merkle_hash_tree written to /workspace/builds/worker-110/source/Cargo.toml
[INFO] crate git repo https://github.com/sergorl/merkle_hash_tree already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "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-110/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-110/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" "+beta-2021-08-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6d831ae61a8306800576da24701341d516179ac088679a39385fac1b94e39479
[INFO] running `Command { std: "docker" "start" "-a" "6d831ae61a8306800576da24701341d516179ac088679a39385fac1b94e39479", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6d831ae61a8306800576da24701341d516179ac088679a39385fac1b94e39479", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6d831ae61a8306800576da24701341d516179ac088679a39385fac1b94e39479", kill_on_drop: false }`
[INFO] [stdout] 6d831ae61a8306800576da24701341d516179ac088679a39385fac1b94e39479
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-110/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-110/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=warn" "-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" "+beta-2021-08-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 110a96b1f0f08a1f60551205525bb4eb45dc55b2a2076524fd92a71e556f3f4b
[INFO] running `Command { std: "docker" "start" "-a" "110a96b1f0f08a1f60551205525bb4eb45dc55b2a2076524fd92a71e556f3f4b", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling libc v0.2.36
[INFO] [stderr]    Compiling either v1.4.0
[INFO] [stderr]    Compiling scopeguard v0.3.3
[INFO] [stderr]    Compiling rayon-core v1.3.0
[INFO] [stderr]    Compiling gcc v0.3.54
[INFO] [stderr]    Compiling lazy_static v0.2.11
[INFO] [stderr]    Compiling rustc-serialize v0.3.24
[INFO] [stderr]    Compiling coco v0.1.1
[INFO] [stderr]    Compiling rand v0.3.20
[INFO] [stderr]    Compiling num_cpus v1.8.0
[INFO] [stderr]    Compiling time v0.1.39
[INFO] [stderr]    Compiling num_cpus v0.2.13
[INFO] [stderr]    Compiling rand v0.4.2
[INFO] [stderr]    Compiling rust-crypto v0.2.36
[INFO] [stderr]    Compiling rayon v0.9.0
[INFO] [stderr]    Compiling merkle_hash_tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `num_thread`
[INFO] [stdout]    --> src/lib.rs:272:13
[INFO] [stdout]     |
[INFO] [stdout] 272 |         let num_thread: usize;
[INFO] [stdout]     |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_thread`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:255:78
[INFO] [stdout]     |
[INFO] [stdout] 255 | fn create_hash_level(hash_tree: &mut Vec<Vec<u8>>, pool: &rayon::ThreadPool, num_cpus: usize) {
[INFO] [stdout]     |                                                                              ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:305:5
[INFO] [stdout]     |
[INFO] [stdout] 305 |     num_cpus: usize,
[INFO] [stdout]     |     ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |         write!(f, "{}\n", "Tree: ");
[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]     = 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/lib.rs:161:13
[INFO] [stdout]     |
[INFO] [stdout] 161 |             write!(f, "Level {}: \n", level);
[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/lib.rs:164:17
[INFO] [stdout]     |
[INFO] [stdout] 164 |                 write!(f, "hash {}: {}\n", index, to_hex_string(hash));
[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/lib.rs:170:13
[INFO] [stdout]     |
[INFO] [stdout] 170 | /             write!(
[INFO] [stdout] 171 | |                 f,
[INFO] [stdout] 172 | |                 "{}\n",
[INFO] [stdout] 173 | |                 "--------------------------------------------------------------------"
[INFO] [stdout] 174 | |             );
[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: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `merkle_tree::to_hex_string`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use merkle_tree::to_hex_string;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `start`
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let start = PreciseTime::now();
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_start`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `end`
[INFO] [stdout]   --> src/main.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let end = PreciseTime::now();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_end`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let mut num_block: usize = 8 * 2;
[INFO] [stdout]    |         ----^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let mut size_block: usize = 32;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1m 26s
[INFO] running `Command { std: "docker" "inspect" "110a96b1f0f08a1f60551205525bb4eb45dc55b2a2076524fd92a71e556f3f4b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "110a96b1f0f08a1f60551205525bb4eb45dc55b2a2076524fd92a71e556f3f4b", kill_on_drop: false }`
[INFO] [stdout] 110a96b1f0f08a1f60551205525bb4eb45dc55b2a2076524fd92a71e556f3f4b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-110/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-110/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=warn" "-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" "+beta-2021-08-01" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 37fc00a96a6c4135db22a9b939cb5e512d4cb62d465c17ea3ca6087ede43cc4b
[INFO] running `Command { std: "docker" "start" "-a" "37fc00a96a6c4135db22a9b939cb5e512d4cb62d465c17ea3ca6087ede43cc4b", kill_on_drop: false }`
[INFO] [stdout] warning: unused variable: `num_thread`
[INFO] [stdout]    --> src/lib.rs:272:13
[INFO] [stdout]     |
[INFO] [stdout] 272 |         let num_thread: usize;
[INFO] [stdout]     |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_thread`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:255:78
[INFO] [stdout]     |
[INFO] [stdout] 255 | fn create_hash_level(hash_tree: &mut Vec<Vec<u8>>, pool: &rayon::ThreadPool, num_cpus: usize) {
[INFO] [stdout]     |                                                                              ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:305:5
[INFO] [stdout]     |
[INFO] [stdout] 305 |     num_cpus: usize,
[INFO] [stdout]     |     ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |         write!(f, "{}\n", "Tree: ");
[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]     = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling merkle_hash_tree v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:161:13
[INFO] [stdout]     |
[INFO] [stdout] 161 |             write!(f, "Level {}: \n", level);
[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/lib.rs:164:17
[INFO] [stdout]     |
[INFO] [stdout] 164 |                 write!(f, "hash {}: {}\n", index, to_hex_string(hash));
[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/lib.rs:170:13
[INFO] [stdout]     |
[INFO] [stdout] 170 | /             write!(
[INFO] [stdout] 171 | |                 f,
[INFO] [stdout] 172 | |                 "{}\n",
[INFO] [stdout] 173 | |                 "--------------------------------------------------------------------"
[INFO] [stdout] 174 | |             );
[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: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `merkle_tree::to_hex_string`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use merkle_tree::to_hex_string;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `start`
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let start = PreciseTime::now();
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_start`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `end`
[INFO] [stdout]   --> src/main.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let end = PreciseTime::now();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_end`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let mut num_block: usize = 8 * 2;
[INFO] [stdout]    |         ----^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let mut size_block: usize = 32;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> tests/test.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(test)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `merkle_tree::to_hex_string`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use merkle_tree::to_hex_string;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `start`
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let start = PreciseTime::now();
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_start`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `end`
[INFO] [stdout]   --> src/main.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let end = PreciseTime::now();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_end`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let mut num_block: usize = 8 * 2;
[INFO] [stdout]    |         ----^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let mut size_block: usize = 32;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `merkle_hash_tree` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `num_thread`
[INFO] [stdout]    --> src/lib.rs:272:13
[INFO] [stdout]     |
[INFO] [stdout] 272 |         let num_thread: usize;
[INFO] [stdout]     |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_thread`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:255:78
[INFO] [stdout]     |
[INFO] [stdout] 255 | fn create_hash_level(hash_tree: &mut Vec<Vec<u8>>, pool: &rayon::ThreadPool, num_cpus: usize) {
[INFO] [stdout]     |                                                                              ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_cpus`
[INFO] [stdout]    --> src/lib.rs:305:5
[INFO] [stdout]     |
[INFO] [stdout] 305 |     num_cpus: usize,
[INFO] [stdout]     |     ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_cpus`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |         write!(f, "{}\n", "Tree: ");
[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]     = 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/lib.rs:161:13
[INFO] [stdout]     |
[INFO] [stdout] 161 |             write!(f, "Level {}: \n", level);
[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/lib.rs:164:17
[INFO] [stdout]     |
[INFO] [stdout] 164 |                 write!(f, "hash {}: {}\n", index, to_hex_string(hash));
[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/lib.rs:170:13
[INFO] [stdout]     |
[INFO] [stdout] 170 | /             write!(
[INFO] [stdout] 171 | |                 f,
[INFO] [stdout] 172 | |                 "{}\n",
[INFO] [stdout] 173 | |                 "--------------------------------------------------------------------"
[INFO] [stdout] 174 | |             );
[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: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "37fc00a96a6c4135db22a9b939cb5e512d4cb62d465c17ea3ca6087ede43cc4b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "37fc00a96a6c4135db22a9b939cb5e512d4cb62d465c17ea3ca6087ede43cc4b", kill_on_drop: false }`
[INFO] [stdout] 37fc00a96a6c4135db22a9b939cb5e512d4cb62d465c17ea3ca6087ede43cc4b
