[INFO] crate comacro 0.0.1 is already in cache
[INFO] checking comacro-0.0.1 against try#e4dba30b9b475d8750370c4dfb49b6541990904d for pr-71393
[INFO] extracting crate comacro 0.0.1 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate comacro 0.0.1 on toolchain e4dba30b9b475d8750370c4dfb49b6541990904d
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate comacro 0.0.1
[INFO] finished tweaking crates.io crate comacro 0.0.1
[INFO] tweaked toml for crates.io crate comacro 0.0.1 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 1d15608a6994f7183a527f3c9538dd656e50a95d8a315b1d6e7c54a557fc3827
[INFO] running `"docker" "start" "-a" "1d15608a6994f7183a527f3c9538dd656e50a95d8a315b1d6e7c54a557fc3827"`
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]     Checking regex-syntax v0.6.17
[INFO] [stderr]     Checking quick-error v1.2.3
[INFO] [stderr]     Checking termcolor v1.1.0
[INFO] [stderr]     Checking thread_local v1.0.1
[INFO] [stderr]     Checking humantime v1.3.0
[INFO] [stderr]     Checking aho-corasick v0.7.10
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking regex v1.3.7
[INFO] [stderr]     Checking comacro v0.0.1 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unnecessary parentheses around pattern
[INFO] [stderr]   --> src/trace.rs:84:21
[INFO] [stderr]    |
[INFO] [stderr] 84 |                 let ((&x, rest)) = rest.split_first().unwrap();
[INFO] [stderr]    |                     ^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: use of deprecated item 'core::str::<impl str>::trim_left_matches': superseded by `trim_start_matches`
[INFO] [stderr]   --> src/matchcode.rs:58:22
[INFO] [stderr]    |
[INFO] [stderr] 58 |         let x_id = x.trim_left_matches("IDENT_");
[INFO] [stderr]    |                      ^^^^^^^^^^^^^^^^^ help: replace the use of the deprecated item: `trim_start_matches`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(deprecated)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: use of deprecated item 'core::str::<impl str>::trim_left_matches': superseded by `trim_start_matches`
[INFO] [stderr]   --> src/matchcode.rs:59:24
[INFO] [stderr]    |
[INFO] [stderr] 59 |         let x_expr = x.trim_left_matches("EXPR_");
[INFO] [stderr]    |                        ^^^^^^^^^^^^^^^^^ help: replace the use of the deprecated item: `trim_start_matches`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/repr.rs:270:29
[INFO] [stderr]     |
[INFO] [stderr] 270 |     fn push_byte(&mut self, x: u8) {}
[INFO] [stderr]     |                             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/repr.rs:271:32
[INFO] [stderr]     |
[INFO] [stderr] 271 |     fn extend_bytes(&mut self, x: &[u8]) {}
[INFO] [stderr]     |                                ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Cont`
[INFO] [stderr]   --> src/tokens.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     Cont,
[INFO] [stderr]    |     ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:41:9
[INFO] [stderr]    |
[INFO] [stderr] 41 |         write!(self.buf, "${}", x);
[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]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:47:9
[INFO] [stderr]    |
[INFO] [stderr] 47 |         write!(self.buf, "{}", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:53:9
[INFO] [stderr]    |
[INFO] [stderr] 53 |         write!(self.buf, "{}", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:59:9
[INFO] [stderr]    |
[INFO] [stderr] 59 |         write!(self.buf, "{}{{", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:65:9
[INFO] [stderr]    |
[INFO] [stderr] 65 |         write!(self.buf, "}}");
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:71:13
[INFO] [stderr]    |
[INFO] [stderr] 71 |             write!(self.buf, "\n");
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:90:9
[INFO] [stderr]    |
[INFO] [stderr] 90 |         write!(buf, "[");
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:113:13
[INFO] [stderr]     |
[INFO] [stderr] 113 |             write!(self.buf, "]");
[INFO] [stderr]     |             ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:120:9
[INFO] [stderr]     |
[INFO] [stderr] 120 |         write!(self.buf, "\"${}\"", x);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:126:9
[INFO] [stderr]     |
[INFO] [stderr] 126 |         write!(self.buf, "{}", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:132:9
[INFO] [stderr]     |
[INFO] [stderr] 132 |         write!(self.buf, "\"{}\"", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:138:9
[INFO] [stderr]     |
[INFO] [stderr] 138 |         write!(self.buf, "[\"{}\"", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:143:9
[INFO] [stderr]     |
[INFO] [stderr] 143 |         write!(self.buf, "]");
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: 19 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Checking env_logger v0.5.13
[INFO] [stderr] warning: unnecessary parentheses around pattern
[INFO] [stderr]   --> src/trace.rs:84:21
[INFO] [stderr]    |
[INFO] [stderr] 84 |                 let ((&x, rest)) = rest.split_first().unwrap();
[INFO] [stderr]    |                     ^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: use of deprecated item 'core::str::<impl str>::trim_left_matches': superseded by `trim_start_matches`
[INFO] [stderr]   --> src/matchcode.rs:58:22
[INFO] [stderr]    |
[INFO] [stderr] 58 |         let x_id = x.trim_left_matches("IDENT_");
[INFO] [stderr]    |                      ^^^^^^^^^^^^^^^^^ help: replace the use of the deprecated item: `trim_start_matches`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(deprecated)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: use of deprecated item 'core::str::<impl str>::trim_left_matches': superseded by `trim_start_matches`
[INFO] [stderr]   --> src/matchcode.rs:59:24
[INFO] [stderr]    |
[INFO] [stderr] 59 |         let x_expr = x.trim_left_matches("EXPR_");
[INFO] [stderr]    |                        ^^^^^^^^^^^^^^^^^ help: replace the use of the deprecated item: `trim_start_matches`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/repr.rs:270:29
[INFO] [stderr]     |
[INFO] [stderr] 270 |     fn push_byte(&mut self, x: u8) {}
[INFO] [stderr]     |                             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/repr.rs:271:32
[INFO] [stderr]     |
[INFO] [stderr] 271 |     fn extend_bytes(&mut self, x: &[u8]) {}
[INFO] [stderr]     |                                ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Cont`
[INFO] [stderr]   --> src/tokens.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     Cont,
[INFO] [stderr]    |     ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:41:9
[INFO] [stderr]    |
[INFO] [stderr] 41 |         write!(self.buf, "${}", x);
[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]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:47:9
[INFO] [stderr]    |
[INFO] [stderr] 47 |         write!(self.buf, "{}", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:53:9
[INFO] [stderr]    |
[INFO] [stderr] 53 |         write!(self.buf, "{}", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:59:9
[INFO] [stderr]    |
[INFO] [stderr] 59 |         write!(self.buf, "{}{{", s);
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:65:9
[INFO] [stderr]    |
[INFO] [stderr] 65 |         write!(self.buf, "}}");
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:71:13
[INFO] [stderr]    |
[INFO] [stderr] 71 |             write!(self.buf, "\n");
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/repr.rs:90:9
[INFO] [stderr]    |
[INFO] [stderr] 90 |         write!(buf, "[");
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:113:13
[INFO] [stderr]     |
[INFO] [stderr] 113 |             write!(self.buf, "]");
[INFO] [stderr]     |             ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:120:9
[INFO] [stderr]     |
[INFO] [stderr] 120 |         write!(self.buf, "\"${}\"", x);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:126:9
[INFO] [stderr]     |
[INFO] [stderr] 126 |         write!(self.buf, "{}", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:132:9
[INFO] [stderr]     |
[INFO] [stderr] 132 |         write!(self.buf, "\"{}\"", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:138:9
[INFO] [stderr]     |
[INFO] [stderr] 138 |         write!(self.buf, "[\"{}\"", s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/repr.rs:143:9
[INFO] [stderr]     |
[INFO] [stderr] 143 |         write!(self.buf, "]");
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: 19 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 14.56s
[INFO] running `"docker" "inspect" "1d15608a6994f7183a527f3c9538dd656e50a95d8a315b1d6e7c54a557fc3827"`
[INFO] running `"docker" "rm" "-f" "1d15608a6994f7183a527f3c9538dd656e50a95d8a315b1d6e7c54a557fc3827"`
[INFO] [stdout] 1d15608a6994f7183a527f3c9538dd656e50a95d8a315b1d6e7c54a557fc3827