[INFO] cloning repository https://github.com/KyleBarton/klh
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/KyleBarton/klh" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKyleBarton%2Fklh", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKyleBarton%2Fklh'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ff6898ee6038730a5cb188fa207cc9156eae5132
[INFO] testing KyleBarton/klh against try#eafdee2dfae8c2233b74f98b123308be7ccefcc6 for pr-79296
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKyleBarton%2Fklh" "/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/KyleBarton/klh on toolchain eafdee2dfae8c2233b74f98b123308be7ccefcc6
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/KyleBarton/klh
[INFO] finished tweaking git repo https://github.com/KyleBarton/klh
[INFO] tweaked toml for git repo https://github.com/KyleBarton/klh written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/KyleBarton/klh already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded simplelog v0.8.0
[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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 285e9fa935eab3dd8aa1df7f30f96b87cb58684532e9dd7b3a2c1ba06aafe92e
[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" "285e9fa935eab3dd8aa1df7f30f96b87cb58684532e9dd7b3a2c1ba06aafe92e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "285e9fa935eab3dd8aa1df7f30f96b87cb58684532e9dd7b3a2c1ba06aafe92e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "285e9fa935eab3dd8aa1df7f30f96b87cb58684532e9dd7b3a2c1ba06aafe92e", kill_on_drop: false }`
[INFO] [stdout] 285e9fa935eab3dd8aa1df7f30f96b87cb58684532e9dd7b3a2c1ba06aafe92e
[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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3d3b257d21e8e559d05afb410f9495c700466d77422f3721062894d642487ae9
[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" "3d3b257d21e8e559d05afb410f9495c700466d77422f3721062894d642487ae9", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling libc v0.2.70
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling termcolor v1.1.0
[INFO] [stderr]    Compiling numtoa v0.1.0
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]    Compiling num-integer v0.1.43
[INFO] [stderr]    Compiling time v0.1.43
[INFO] [stderr]    Compiling termion v1.5.5
[INFO] [stderr]    Compiling termios v0.3.2
[INFO] [stderr]    Compiling chrono v0.4.13
[INFO] [stderr]    Compiling simplelog v0.8.0
[INFO] [stderr]    Compiling klh v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `index`
[INFO] [stdout]    --> src/buffer.rs:208:31
[INFO] [stdout]     |
[INFO] [stdout] 208 |   fn get_char_at_index(&self, index: i64) -> Result<char, String> {
[INFO] [stdout]     |                               ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `query_char`
[INFO] [stdout]    --> src/buffer.rs:212:31
[INFO] [stdout]     |
[INFO] [stdout] 212 |   fn get_next_for_char(&self, query_char: char) -> Result<Coordinate, String> {
[INFO] [stdout]     |                               ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_query_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/buffer.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         mem::replace(&mut self.lines[self.point.line], first_line_part);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:110:11
[INFO] [stdout]     |
[INFO] [stdout] 110 |           mem::replace(&mut self.lines[self.point.line], line);
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |         mem::replace(&mut self.lines[new_line], new_line_content);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:148:7
[INFO] [stdout]     |
[INFO] [stdout] 148 |       mem::replace(&mut self.lines[self.point.line], new_line);
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 11.08s
[INFO] running `Command { std: "docker" "inspect" "3d3b257d21e8e559d05afb410f9495c700466d77422f3721062894d642487ae9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d3b257d21e8e559d05afb410f9495c700466d77422f3721062894d642487ae9", kill_on_drop: false }`
[INFO] [stdout] 3d3b257d21e8e559d05afb410f9495c700466d77422f3721062894d642487ae9
[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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 915764c1a705ba99d5343738f9418ebc626f5ed24ecc0471622a0603ea27959d
[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" "915764c1a705ba99d5343738f9418ebc626f5ed24ecc0471622a0603ea27959d", kill_on_drop: false }`
[INFO] [stdout] warning: unused variable: `index`
[INFO] [stdout]    --> src/buffer.rs:208:31
[INFO] [stdout]     |
[INFO] [stdout] 208 |   fn get_char_at_index(&self, index: i64) -> Result<char, String> {
[INFO] [stdout]     |                               ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `query_char`
[INFO] [stdout]    --> src/buffer.rs:212:31
[INFO] [stdout]     |
[INFO] [stdout] 212 |   fn get_next_for_char(&self, query_char: char) -> Result<Coordinate, String> {
[INFO] [stdout]     |                               ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_query_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/buffer.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         mem::replace(&mut self.lines[self.point.line], first_line_part);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling klh v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:110:11
[INFO] [stdout]     |
[INFO] [stdout] 110 |           mem::replace(&mut self.lines[self.point.line], line);
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |         mem::replace(&mut self.lines[new_line], new_line_content);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:148:7
[INFO] [stdout]     |
[INFO] [stdout] 148 |       mem::replace(&mut self.lines[self.point.line], new_line);
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `index`
[INFO] [stdout]    --> src/buffer.rs:208:31
[INFO] [stdout]     |
[INFO] [stdout] 208 |   fn get_char_at_index(&self, index: i64) -> Result<char, String> {
[INFO] [stdout]     |                               ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `query_char`
[INFO] [stdout]    --> src/buffer.rs:212:31
[INFO] [stdout]     |
[INFO] [stdout] 212 |   fn get_next_for_char(&self, query_char: char) -> Result<Coordinate, String> {
[INFO] [stdout]     |                               ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_query_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/buffer.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         mem::replace(&mut self.lines[self.point.line], first_line_part);
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:110:11
[INFO] [stdout]     |
[INFO] [stdout] 110 |           mem::replace(&mut self.lines[self.point.line], line);
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |         mem::replace(&mut self.lines[new_line], new_line_content);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/buffer.rs:148:7
[INFO] [stdout]     |
[INFO] [stdout] 148 |       mem::replace(&mut self.lines[self.point.line], new_line);
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.76s
[INFO] running `Command { std: "docker" "inspect" "915764c1a705ba99d5343738f9418ebc626f5ed24ecc0471622a0603ea27959d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "915764c1a705ba99d5343738f9418ebc626f5ed24ecc0471622a0603ea27959d", kill_on_drop: false }`
[INFO] [stdout] 915764c1a705ba99d5343738f9418ebc626f5ed24ecc0471622a0603ea27959d
[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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+eafdee2dfae8c2233b74f98b123308be7ccefcc6" "test" "--frozen", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 15e009b45d317e1b15f09c7a6114f04f7ea1533c92dba73dc03e9d514f97627e
[INFO] running `Command { std: "docker" "start" "-a" "15e009b45d317e1b15f09c7a6114f04f7ea1533c92dba73dc03e9d514f97627e", kill_on_drop: false }`
[INFO] [stderr] warning: unused variable: `index`
[INFO] [stderr]    --> src/buffer.rs:208:31
[INFO] [stderr]     |
[INFO] [stderr] 208 |   fn get_char_at_index(&self, index: i64) -> Result<char, String> {
[INFO] [stderr]     |                               ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `query_char`
[INFO] [stderr]    --> src/buffer.rs:212:31
[INFO] [stderr]     |
[INFO] [stderr] 212 |   fn get_next_for_char(&self, query_char: char) -> Result<Coordinate, String> {
[INFO] [stderr]     |                               ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_query_char`
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]   --> src/buffer.rs:91:9
[INFO] [stderr]    |
[INFO] [stderr] 91 |         mem::replace(&mut self.lines[self.point.line], first_line_part);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:110:11
[INFO] [stderr]     |
[INFO] [stderr] 110 |           mem::replace(&mut self.lines[self.point.line], line);
[INFO] [stderr]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:133:9
[INFO] [stderr]     |
[INFO] [stderr] 133 |         mem::replace(&mut self.lines[new_line], new_line_content);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:148:7
[INFO] [stderr]     |
[INFO] [stderr] 148 |       mem::replace(&mut self.lines[self.point.line], new_line);
[INFO] [stderr]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: 6 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `index`
[INFO] [stderr]    --> src/buffer.rs:208:31
[INFO] [stderr]     |
[INFO] [stderr] 208 |   fn get_char_at_index(&self, index: i64) -> Result<char, String> {
[INFO] [stderr]     |                               ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `query_char`
[INFO] [stderr]    --> src/buffer.rs:212:31
[INFO] [stderr]     |
[INFO] [stderr] 212 |   fn get_next_for_char(&self, query_char: char) -> Result<Coordinate, String> {
[INFO] [stderr]     |                               ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_query_char`
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]   --> src/buffer.rs:91:9
[INFO] [stderr]    |
[INFO] [stderr] 91 |         mem::replace(&mut self.lines[self.point.line], first_line_part);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:110:11
[INFO] [stderr]     |
[INFO] [stderr] 110 |           mem::replace(&mut self.lines[self.point.line], line);
[INFO] [stderr]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:133:9
[INFO] [stderr]     |
[INFO] [stderr] 133 |         mem::replace(&mut self.lines[new_line], new_line_content);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stderr]    --> src/buffer.rs:148:7
[INFO] [stderr]     |
[INFO] [stderr] 148 |       mem::replace(&mut self.lines[self.point.line], new_line);
[INFO] [stderr]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stderr] 
[INFO] [stderr] warning: 6 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.03s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/klh-045dda852ee6cdc1
[INFO] [stdout] 
[INFO] [stdout] running 22 tests
[INFO] [stdout] test buffer::test::line_buffer_should_delete_newlines ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_delete_some_chars_from_point ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_current_location_backward ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_current_location_down_a_line ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_delete_mid_line ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_in_middle_of_content ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_point_on_append ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_delete_line_mid_buffer ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_current_location_forward ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_delete_char_from_point ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_current_location_up_a_line ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_newline_in_midddle_of_content ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_move_point_across_newlines_on_append ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_newline ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_not_delete_past_beginning_of_buffer ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_not_move_current_location_past_beginning_of_buffer ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_not_move_current_location_past_end_of_buffer ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_at_point ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_consecutive_newlines ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_append_many_at_point ... ok
[INFO] [stdout] test buffer::test::line_buffer_should_not_delete_past_beginning_mid_line ... ok
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/klh-420378d46b064dc4
[INFO] [stdout] test buffer::test::line_buffer_should_append_existing_text ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 22 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests klh
[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
[INFO] [stdout] 
[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
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "15e009b45d317e1b15f09c7a6114f04f7ea1533c92dba73dc03e9d514f97627e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "15e009b45d317e1b15f09c7a6114f04f7ea1533c92dba73dc03e9d514f97627e", kill_on_drop: false }`
[INFO] [stdout] 15e009b45d317e1b15f09c7a6114f04f7ea1533c92dba73dc03e9d514f97627e