[INFO] fetching crate slog-scope-stdlog 0.2.0...
[INFO] checking slog-scope-stdlog-0.2.0 against beta-2020-07-24 for pr-75494-beta
[INFO] extracting crate slog-scope-stdlog 0.2.0 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate slog-scope-stdlog 0.2.0 on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate slog-scope-stdlog 0.2.0
[INFO] finished tweaking crates.io crate slog-scope-stdlog 0.2.0
[INFO] tweaked toml for crates.io crate slog-scope-stdlog 0.2.0 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", 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] f713e52a9d6b7f23eeb54499f1dc67e5933b9a620437748c8c4fc27b67c874d1
[INFO] running `Command { std: "docker" "start" "-a" "f713e52a9d6b7f23eeb54499f1dc67e5933b9a620437748c8c4fc27b67c874d1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f713e52a9d6b7f23eeb54499f1dc67e5933b9a620437748c8c4fc27b67c874d1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f713e52a9d6b7f23eeb54499f1dc67e5933b9a620437748c8c4fc27b67c874d1", kill_on_drop: false }`
[INFO] [stdout] f713e52a9d6b7f23eeb54499f1dc67e5933b9a620437748c8c4fc27b67c874d1
[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=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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4864767940f6d10acfcee5f0c4a96122e00063fb67c6e1dbdcd19d8b5a9ed523
[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" "4864767940f6d10acfcee5f0c4a96122e00063fb67c6e1dbdcd19d8b5a9ed523", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.76
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]     Checking crossbeam v0.2.12
[INFO] [stderr]    Compiling num-integer v0.1.43
[INFO] [stderr]    Compiling num-iter v0.1.41
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking slog-extra v0.1.2
[INFO] [stderr]     Checking slog-scope v0.2.2
[INFO] [stderr]     Checking slog-stream v1.2.1
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stderr]     Checking time v0.1.43
[INFO] [stderr]     Checking isatty v0.1.9
[INFO] [stderr]     Checking num v0.1.42
[INFO] [stderr]     Checking chrono v0.2.25
[INFO] [stderr]     Checking slog-term v1.5.0
[INFO] [stderr]     Checking slog-scope-stdlog v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |         try!(write!(f, "{}", self.info.msg()));
[INFO] [stdout]     |         ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:142:25
[INFO] [stdout]     |
[INFO] [stdout] 142 |                         try!(ser.io().write_all(", ".as_bytes()));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:143:25
[INFO] [stdout]     |
[INFO] [stdout] 143 |                         try!(v.serialize(self.info, k, &mut ser));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:147:25
[INFO] [stdout]     |
[INFO] [stdout] 147 |                         try!(ser.io().write_all(", ".as_bytes()));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:148:25
[INFO] [stdout]     |
[INFO] [stdout] 148 |                         try!(v.serialize(self.info, k, &mut ser));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:155:9
[INFO] [stdout]     |
[INFO] [stdout] 155 |         try!(res);
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:219:9
[INFO] [stdout]     |
[INFO] [stdout] 219 |         try!(write!(self.io, "{}{}{}", key, self.separator, "None"));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:223:9
[INFO] [stdout]     |
[INFO] [stdout] 223 |         try!(write!(self.io, "{}", key));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:228:9
[INFO] [stdout]     |
[INFO] [stdout] 228 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:233:9
[INFO] [stdout]     |
[INFO] [stdout] 233 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:238:9
[INFO] [stdout]     |
[INFO] [stdout] 238 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:242:9
[INFO] [stdout]     |
[INFO] [stdout] 242 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:247:9
[INFO] [stdout]     |
[INFO] [stdout] 247 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:251:9
[INFO] [stdout]     |
[INFO] [stdout] 251 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:255:9
[INFO] [stdout]     |
[INFO] [stdout] 255 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:259:9
[INFO] [stdout]     |
[INFO] [stdout] 259 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:263:9
[INFO] [stdout]     |
[INFO] [stdout] 263 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:267:9
[INFO] [stdout]     |
[INFO] [stdout] 267 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:271:9
[INFO] [stdout]     |
[INFO] [stdout] 271 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:275:9
[INFO] [stdout]     |
[INFO] [stdout] 275 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:279:9
[INFO] [stdout]     |
[INFO] [stdout] 279 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:283:9
[INFO] [stdout]     |
[INFO] [stdout] 283 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:287:9
[INFO] [stdout]     |
[INFO] [stdout] 287 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:291:9
[INFO] [stdout]     |
[INFO] [stdout] 291 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]   --> lib.rs:27:1
[INFO] [stdout]    |
[INFO] [stdout] 27 | #[macro_use]
[INFO] [stdout]    | ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:133:9
[INFO] [stdout]     |
[INFO] [stdout] 133 |         try!(write!(f, "{}", self.info.msg()));
[INFO] [stdout]     |         ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:142:25
[INFO] [stdout]     |
[INFO] [stdout] 142 |                         try!(ser.io().write_all(", ".as_bytes()));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:143:25
[INFO] [stdout]     |
[INFO] [stdout] 143 |                         try!(v.serialize(self.info, k, &mut ser));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:147:25
[INFO] [stdout]     |
[INFO] [stdout] 147 |                         try!(ser.io().write_all(", ".as_bytes()));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:148:25
[INFO] [stdout]     |
[INFO] [stdout] 148 |                         try!(v.serialize(self.info, k, &mut ser));
[INFO] [stdout]     |                         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:155:9
[INFO] [stdout]     |
[INFO] [stdout] 155 |         try!(res);
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:219:9
[INFO] [stdout]     |
[INFO] [stdout] 219 |         try!(write!(self.io, "{}{}{}", key, self.separator, "None"));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:223:9
[INFO] [stdout]     |
[INFO] [stdout] 223 |         try!(write!(self.io, "{}", key));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:228:9
[INFO] [stdout]     |
[INFO] [stdout] 228 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:233:9
[INFO] [stdout]     |
[INFO] [stdout] 233 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:238:9
[INFO] [stdout]     |
[INFO] [stdout] 238 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:242:9
[INFO] [stdout]     |
[INFO] [stdout] 242 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:247:9
[INFO] [stdout]     |
[INFO] [stdout] 247 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:251:9
[INFO] [stdout]     |
[INFO] [stdout] 251 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:255:9
[INFO] [stdout]     |
[INFO] [stdout] 255 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:259:9
[INFO] [stdout]     |
[INFO] [stdout] 259 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:263:9
[INFO] [stdout]     |
[INFO] [stdout] 263 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:267:9
[INFO] [stdout]     |
[INFO] [stdout] 267 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:271:9
[INFO] [stdout]     |
[INFO] [stdout] 271 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:275:9
[INFO] [stdout]     |
[INFO] [stdout] 275 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:279:9
[INFO] [stdout]     |
[INFO] [stdout] 279 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:283:9
[INFO] [stdout]     |
[INFO] [stdout] 283 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:287:9
[INFO] [stdout]     |
[INFO] [stdout] 287 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'try': use the `?` operator instead
[INFO] [stdout]    --> lib.rs:291:9
[INFO] [stdout]     |
[INFO] [stdout] 291 |         try!(write!(self.io, "{}{}{}", key, self.separator, val));
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]   --> lib.rs:27:1
[INFO] [stdout]    |
[INFO] [stdout] 27 | #[macro_use]
[INFO] [stdout]    | ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 25 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 25 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 9.65s
[INFO] running `Command { std: "docker" "inspect" "4864767940f6d10acfcee5f0c4a96122e00063fb67c6e1dbdcd19d8b5a9ed523", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4864767940f6d10acfcee5f0c4a96122e00063fb67c6e1dbdcd19d8b5a9ed523", kill_on_drop: false }`
[INFO] [stdout] 4864767940f6d10acfcee5f0c4a96122e00063fb67c6e1dbdcd19d8b5a9ed523
