[INFO] cloning repository https://github.com/zhangsoledad/lmdb_test
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/zhangsoledad/lmdb_test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhangsoledad%2Flmdb_test", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhangsoledad%2Flmdb_test'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8269d7b73a989da8ccdcbebb734cd51f372b037f
[INFO] testing zhangsoledad/lmdb_test against beta-2021-01-01 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhangsoledad%2Flmdb_test" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/zhangsoledad/lmdb_test on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/zhangsoledad/lmdb_test
[INFO] finished tweaking git repo https://github.com/zhangsoledad/lmdb_test
[INFO] tweaked toml for git repo https://github.com/zhangsoledad/lmdb_test written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/zhangsoledad/lmdb_test already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded conv v0.3.3
[INFO] [stderr]   Downloaded either v1.1.0
[INFO] [stderr]   Downloaded byteorder v1.1.0
[INFO] [stderr]   Downloaded gcc v0.3.53
[INFO] [stderr]   Downloaded num-traits v0.1.40
[INFO] [stderr]   Downloaded num_cpus v1.6.2
[INFO] [stderr]   Downloaded lazy_static v0.2.8
[INFO] [stderr]   Downloaded rayon-core v1.2.1
[INFO] [stderr]   Downloaded rayon v0.8.2
[INFO] [stderr]   Downloaded libc v0.2.30
[INFO] [stderr]   Downloaded serde v1.0.11
[INFO] [stderr]   Downloaded serde_derive_internals v0.15.1
[INFO] [stderr]   Downloaded serde_derive v1.0.11
[INFO] [stderr]   Downloaded magenta-sys v0.1.1
[INFO] [stderr]   Downloaded futures v0.1.15
[INFO] [stderr]   Downloaded magenta v0.1.1
[INFO] [stderr]   Downloaded tempdir v0.3.5
[INFO] [stderr]   Downloaded bincode v0.8.0
[INFO] [stderr]   Downloaded pkg-config v0.3.9
[INFO] [stderr]   Downloaded scopeguard v0.3.2
[INFO] [stderr]   Downloaded coco v0.1.1
[INFO] [stderr]   Downloaded rand v0.3.16
[INFO] [stderr]   Downloaded lmdb v0.7.1
[INFO] [stderr]   Downloaded lmdb-sys v0.7.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e9ffe83f0e1f714d4ff6034838223f35236f62f19225db67d2cacf08044cba51
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "e9ffe83f0e1f714d4ff6034838223f35236f62f19225db67d2cacf08044cba51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e9ffe83f0e1f714d4ff6034838223f35236f62f19225db67d2cacf08044cba51", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e9ffe83f0e1f714d4ff6034838223f35236f62f19225db67d2cacf08044cba51", kill_on_drop: false }`
[INFO] [stdout] e9ffe83f0e1f714d4ff6034838223f35236f62f19225db67d2cacf08044cba51
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 693aa85a136d399805810fc971c094222aa8655498fea3344baf68d5f147ebc8
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "693aa85a136d399805810fc971c094222aa8655498fea3344baf68d5f147ebc8", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling futures v0.1.15
[INFO] [stderr]    Compiling serde v1.0.11
[INFO] [stderr]    Compiling num_cpus v1.6.2
[INFO] [stderr]    Compiling lmdb-sys v0.7.1
[INFO] [stderr]    Compiling tempdir v0.3.5
[INFO] [stderr]    Compiling rayon-core v1.2.1
[INFO] [stderr]    Compiling lmdb v0.7.1
[INFO] [stderr]    Compiling rayon v0.8.2
[INFO] [stderr]    Compiling bincode v0.8.0
[INFO] [stderr]    Compiling lmdb_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Cursor`
[INFO] [stdout]  --> src/lmdb.rs:3:14
[INFO] [stdout]   |
[INFO] [stdout] 3 | use libmdb::{Cursor, Database, DatabaseFlags, Environment, Transaction, WriteFlags};
[INFO] [stdout]   |              ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rayon::prelude`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use rayon::prelude::*;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     db.clear();
[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 return value of `std::iter::Iterator::collect` that must be used
[INFO] [stdout]   --> src/main.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 | /     height
[INFO] [stdout] 23 | |         .iter()
[INFO] [stdout] 24 | |         .map(|height| { db.save_height(*height); })
[INFO] [stdout] 25 | |         .collect::<Vec<()>>();
[INFO] [stdout]    | |______________________________^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:24:25
[INFO] [stdout]    |
[INFO] [stdout] 24 |         .map(|height| { db.save_height(*height); })
[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: constant `height_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:6:7
[INFO] [stdout]   |
[INFO] [stdout] 6 | const height_key: [u8; 1] = [104];
[INFO] [stdout]   |       ^^^^^^^^^^ help: convert the identifier to upper case: `HEIGHT_KEY`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_upper_case_globals)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `head_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 | const head_key: [u8; 1] = [105];
[INFO] [stdout]   |       ^^^^^^^^ help: convert the identifier to upper case: `HEAD_KEY`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `tail_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 | const tail_key: [u8; 1] = [116];
[INFO] [stdout]   |       ^^^^^^^^ help: convert the identifier to upper case: `TAIL_KEY`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 22.74s
[INFO] running `Command { std: "docker" "inspect" "693aa85a136d399805810fc971c094222aa8655498fea3344baf68d5f147ebc8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "693aa85a136d399805810fc971c094222aa8655498fea3344baf68d5f147ebc8", kill_on_drop: false }`
[INFO] [stdout] 693aa85a136d399805810fc971c094222aa8655498fea3344baf68d5f147ebc8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d168f9371984a2f6bd6819be6c764b0edc8de9e9664883abc7fe1b5ee1a31c32
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "d168f9371984a2f6bd6819be6c764b0edc8de9e9664883abc7fe1b5ee1a31c32", kill_on_drop: false }`
[INFO] [stderr]    Compiling lmdb_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Cursor`
[INFO] [stdout]  --> src/lmdb.rs:3:14
[INFO] [stdout]   |
[INFO] [stdout] 3 | use libmdb::{Cursor, Database, DatabaseFlags, Environment, Transaction, WriteFlags};
[INFO] [stdout]   |              ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rayon::prelude`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use rayon::prelude::*;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     db.clear();
[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 return value of `std::iter::Iterator::collect` that must be used
[INFO] [stdout]   --> src/main.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 | /     height
[INFO] [stdout] 23 | |         .iter()
[INFO] [stdout] 24 | |         .map(|height| { db.save_height(*height); })
[INFO] [stdout] 25 | |         .collect::<Vec<()>>();
[INFO] [stdout]    | |______________________________^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:24:25
[INFO] [stdout]    |
[INFO] [stdout] 24 |         .map(|height| { db.save_height(*height); })
[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: constant `height_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:6:7
[INFO] [stdout]   |
[INFO] [stdout] 6 | const height_key: [u8; 1] = [104];
[INFO] [stdout]   |       ^^^^^^^^^^ help: convert the identifier to upper case: `HEIGHT_KEY`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_upper_case_globals)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `head_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 | const head_key: [u8; 1] = [105];
[INFO] [stdout]   |       ^^^^^^^^ help: convert the identifier to upper case: `HEAD_KEY`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `tail_key` should have an upper case name
[INFO] [stdout]  --> src/lmdb.rs:8:7
[INFO] [stdout]   |
[INFO] [stdout] 8 | const tail_key: [u8; 1] = [116];
[INFO] [stdout]   |       ^^^^^^^^ help: convert the identifier to upper case: `TAIL_KEY`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.25s
[INFO] running `Command { std: "docker" "inspect" "d168f9371984a2f6bd6819be6c764b0edc8de9e9664883abc7fe1b5ee1a31c32", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d168f9371984a2f6bd6819be6c764b0edc8de9e9664883abc7fe1b5ee1a31c32", kill_on_drop: false }`
[INFO] [stdout] d168f9371984a2f6bd6819be6c764b0edc8de9e9664883abc7fe1b5ee1a31c32
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] b9ce9dbced0cee2ea75f7243cba95099fce88d46ac0c1411f777c915caa033bb
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "b9ce9dbced0cee2ea75f7243cba95099fce88d46ac0c1411f777c915caa033bb", kill_on_drop: false }`
[INFO] [stderr] warning: unused import: `Cursor`
[INFO] [stderr]  --> src/lmdb.rs:3:14
[INFO] [stderr]   |
[INFO] [stderr] 3 | use libmdb::{Cursor, Database, DatabaseFlags, Environment, Transaction, WriteFlags};
[INFO] [stderr]   |              ^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `rayon::prelude`
[INFO] [stderr]   --> src/main.rs:11:5
[INFO] [stderr]    |
[INFO] [stderr] 11 | use rayon::prelude::*;
[INFO] [stderr]    |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     db.clear();
[INFO] [stderr]    |     ^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::iter::Iterator::collect` that must be used
[INFO] [stderr]   --> src/main.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 | /     height
[INFO] [stderr] 23 | |         .iter()
[INFO] [stderr] 24 | |         .map(|height| { db.save_height(*height); })
[INFO] [stderr] 25 | |         .collect::<Vec<()>>();
[INFO] [stderr]    | |______________________________^
[INFO] [stderr]    |
[INFO] [stderr]    = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:24:25
[INFO] [stderr]    |
[INFO] [stderr] 24 |         .map(|height| { db.save_height(*height); })
[INFO] [stderr]    |                         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: constant `height_key` should have an upper case name
[INFO] [stderr]  --> src/lmdb.rs:6:7
[INFO] [stderr]   |
[INFO] [stderr] 6 | const height_key: [u8; 1] = [104];
[INFO] [stderr]   |       ^^^^^^^^^^ help: convert the identifier to upper case: `HEIGHT_KEY`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(non_upper_case_globals)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: constant `head_key` should have an upper case name
[INFO] [stderr]  --> src/lmdb.rs:7:7
[INFO] [stderr]   |
[INFO] [stderr] 7 | const head_key: [u8; 1] = [105];
[INFO] [stderr]   |       ^^^^^^^^ help: convert the identifier to upper case: `HEAD_KEY`
[INFO] [stderr] 
[INFO] [stderr] warning: constant `tail_key` should have an upper case name
[INFO] [stderr]  --> src/lmdb.rs:8:7
[INFO] [stderr]   |
[INFO] [stderr] 8 | const tail_key: [u8; 1] = [116];
[INFO] [stderr]   |       ^^^^^^^^ help: convert the identifier to upper case: `TAIL_KEY`
[INFO] [stderr] 
[INFO] [stderr] warning: 8 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.08s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/lmdb_test-0ff8242558eb4bfc
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "b9ce9dbced0cee2ea75f7243cba95099fce88d46ac0c1411f777c915caa033bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b9ce9dbced0cee2ea75f7243cba95099fce88d46ac0c1411f777c915caa033bb", kill_on_drop: false }`
[INFO] [stdout] b9ce9dbced0cee2ea75f7243cba95099fce88d46ac0c1411f777c915caa033bb