[INFO] fetching crate supergit 0.2.1...
[INFO] testing supergit-0.2.1 against master#99e3aef02079e9c10583638520cd0c134dc3a01d for pr-85530
[INFO] extracting crate supergit 0.2.1 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate supergit 0.2.1 on toolchain 99e3aef02079e9c10583638520cd0c134dc3a01d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate supergit 0.2.1
[INFO] finished tweaking crates.io crate supergit 0.2.1
[INFO] tweaked toml for crates.io crate supergit 0.2.1 written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate crates.io crate supergit 0.2.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 715852e48279cfec0697b101eab82d4e07dbb679b3245ee238cdff14933a2f23
[INFO] running `Command { std: "docker" "start" "-a" "715852e48279cfec0697b101eab82d4e07dbb679b3245ee238cdff14933a2f23", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "715852e48279cfec0697b101eab82d4e07dbb679b3245ee238cdff14933a2f23", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "715852e48279cfec0697b101eab82d4e07dbb679b3245ee238cdff14933a2f23", kill_on_drop: false }`
[INFO] [stdout] 715852e48279cfec0697b101eab82d4e07dbb679b3245ee238cdff14933a2f23
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f27d746768a2d1f28737c6edc771846255d9fe4b73e1442fbd6b0174c200567d
[INFO] running `Command { std: "docker" "start" "-a" "f27d746768a2d1f28737c6edc771846255d9fe4b73e1442fbd6b0174c200567d", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.82
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling atomptr v1.0.0
[INFO] [stderr]    Compiling tinyvec v1.1.0
[INFO] [stderr]    Compiling unicode-bidi v0.3.4
[INFO] [stderr]    Compiling form_urlencoded v1.0.0
[INFO] [stderr]    Compiling jobserver v0.1.21
[INFO] [stderr]    Compiling unicode-normalization v0.1.16
[INFO] [stderr]    Compiling cc v1.0.66
[INFO] [stderr]    Compiling idna v0.2.0
[INFO] [stderr]    Compiling libz-sys v1.1.2
[INFO] [stderr]    Compiling openssl-sys v0.9.60
[INFO] [stderr]    Compiling libssh2-sys v0.2.20
[INFO] [stderr]    Compiling libgit2-sys v0.10.0
[INFO] [stderr]    Compiling url v2.2.0
[INFO] [stderr]    Compiling git2 v0.11.0
[INFO] [stderr]    Compiling supergit v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: associated function is never used: `empty`
[INFO] [stdout]    --> src/branch.rs:416:8
[INFO] [stdout]     |
[INFO] [stdout] 416 |     fn empty(&self) -> bool {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `decr_brnum`
[INFO] [stdout]    --> src/branch.rs:428:8
[INFO] [stdout]     |
[INFO] [stdout] 428 |     fn decr_brnum(&self) -> usize {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `append`
[INFO] [stdout]    --> src/branch.rs:436:8
[INFO] [stdout]     |
[INFO] [stdout] 436 |     fn append(&self, id: HashId) {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `path_segs_join`
[INFO] [stdout]   --> src/files/tree_utils.rs:41:15
[INFO] [stdout]    |
[INFO] [stdout] 41 | pub(super) fn path_segs_join(segments: Vec<&str>) -> String {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: comparison is useless due to type limits
[INFO] [stdout]    --> src/branch.rs:452:23
[INFO] [stdout]     |
[INFO] [stdout] 452 |         let next = if vec.len() < 0 {
[INFO] [stdout]     |                       ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_comparisons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 22.33s
[INFO] running `Command { std: "docker" "inspect" "f27d746768a2d1f28737c6edc771846255d9fe4b73e1442fbd6b0174c200567d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f27d746768a2d1f28737c6edc771846255d9fe4b73e1442fbd6b0174c200567d", kill_on_drop: false }`
[INFO] [stdout] f27d746768a2d1f28737c6edc771846255d9fe4b73e1442fbd6b0174c200567d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0161e0a6f87a14d84ff7d923f00586a9ff823d180c97d0e150602553bd5bb439
[INFO] running `Command { std: "docker" "start" "-a" "0161e0a6f87a14d84ff7d923f00586a9ff823d180c97d0e150602553bd5bb439", kill_on_drop: false }`
[INFO] [stdout] warning: associated function is never used: `empty`
[INFO] [stdout]    --> src/branch.rs:416:8
[INFO] [stdout]     |
[INFO] [stdout] 416 |     fn empty(&self) -> bool {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `decr_brnum`
[INFO] [stdout]    --> src/branch.rs:428:8
[INFO] [stdout]     |
[INFO] [stdout] 428 |     fn decr_brnum(&self) -> usize {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `append`
[INFO] [stdout]    --> src/branch.rs:436:8
[INFO] [stdout]     |
[INFO] [stdout] 436 |     fn append(&self, id: HashId) {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `path_segs_join`
[INFO] [stdout]   --> src/files/tree_utils.rs:41:15
[INFO] [stdout]    |
[INFO] [stdout] 41 | pub(super) fn path_segs_join(segments: Vec<&str>) -> String {
[INFO] [stdout]    |               ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: comparison is useless due to type limits
[INFO] [stdout]    --> src/branch.rs:452:23
[INFO] [stdout]     |
[INFO] [stdout] 452 |         let next = if vec.len() < 0 {
[INFO] [stdout]     |                       ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_comparisons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling supergit v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: associated function is never used: `empty`
[INFO] [stdout]    --> src/branch.rs:416:8
[INFO] [stdout]     |
[INFO] [stdout] 416 |     fn empty(&self) -> bool {
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `decr_brnum`
[INFO] [stdout]    --> src/branch.rs:428:8
[INFO] [stdout]     |
[INFO] [stdout] 428 |     fn decr_brnum(&self) -> usize {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `append`
[INFO] [stdout]    --> src/branch.rs:436:8
[INFO] [stdout]     |
[INFO] [stdout] 436 |     fn append(&self, id: HashId) {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: comparison is useless due to type limits
[INFO] [stdout]    --> src/branch.rs:452:23
[INFO] [stdout]     |
[INFO] [stdout] 452 |         let next = if vec.len() < 0 {
[INFO] [stdout]     |                       ^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_comparisons)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.48s
[INFO] running `Command { std: "docker" "inspect" "0161e0a6f87a14d84ff7d923f00586a9ff823d180c97d0e150602553bd5bb439", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0161e0a6f87a14d84ff7d923f00586a9ff823d180c97d0e150602553bd5bb439", kill_on_drop: false }`
[INFO] [stdout] 0161e0a6f87a14d84ff7d923f00586a9ff823d180c97d0e150602553bd5bb439
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+99e3aef02079e9c10583638520cd0c134dc3a01d" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 9fdc45ef76a3fde29ba76b8ea52d836d0c1ab8044b0e9498beee0e4b4872dc55
[INFO] running `Command { std: "docker" "start" "-a" "9fdc45ef76a3fde29ba76b8ea52d836d0c1ab8044b0e9498beee0e4b4872dc55", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: associated function is never used: `empty`
[INFO] [stdout] running 7 tests
[INFO] [stderr]    --> src/branch.rs:416:8
[INFO] [stdout] test files::tree_utils::empty_path ... ok
[INFO] [stderr]     |
[INFO] [stderr] 416 |     fn empty(&self) -> bool {
[INFO] [stderr]     |        ^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `decr_brnum`
[INFO] [stderr]    --> src/branch.rs:428:8
[INFO] [stderr]     |
[INFO] [stderr] 428 |     fn decr_brnum(&self) -> usize {
[INFO] [stderr]     |        ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `append`
[INFO] [stderr]    --> src/branch.rs:436:8
[INFO] [stderr]     |
[INFO] [stderr] 436 |     fn append(&self, id: HashId) {
[INFO] [stderr]     |        ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `path_segs_join`
[INFO] [stderr]   --> src/files/tree_utils.rs:41:15
[INFO] [stderr]    |
[INFO] [stderr] 41 | pub(super) fn path_segs_join(segments: Vec<&str>) -> String {
[INFO] [stderr]    |               ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: comparison is useless due to type limits
[INFO] [stderr]    --> src/branch.rs:452:23
[INFO] [stderr]     |
[INFO] [stderr] 452 |         let next = if vec.len() < 0 {
[INFO] [stderr]     |                       ^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_comparisons)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 5 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `empty`
[INFO] [stderr]    --> src/branch.rs:416:8
[INFO] [stderr]     |
[INFO] [stderr] 416 |     fn empty(&self) -> bool {
[INFO] [stderr]     |        ^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `decr_brnum`
[INFO] [stderr]    --> src/branch.rs:428:8
[INFO] [stderr]     |
[INFO] [stderr] 428 |     fn decr_brnum(&self) -> usize {
[INFO] [stderr]     |        ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `append`
[INFO] [stderr]    --> src/branch.rs:436:8
[INFO] [stderr]     |
[INFO] [stderr] 436 |     fn append(&self, id: HashId) {
[INFO] [stderr]     |        ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: comparison is useless due to type limits
[INFO] [stderr]    --> src/branch.rs:452:23
[INFO] [stderr]     |
[INFO] [stderr] 452 |         let next = if vec.len() < 0 {
[INFO] [stderr]     |                       ^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_comparisons)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 4 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/supergit-9db8147245fb1f19)
[INFO] [stdout] test files::tree_utils::pair_iterator ... ok
[INFO] [stdout] test files::tree_utils::nested_path ... ok
[INFO] [stdout] test files::tree_utils::one_path ... ok
[INFO] [stdout] test files::tree::s_enumerate ... ok
[INFO] [stdout] test files::tree::s_history ... ok
[INFO] [stdout] test files::tree::s_resolve ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s
[INFO] [stdout] 
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/test-ea70e3eeaa9c5e03)
[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] [stderr]    Doc-tests supergit
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test src/lib.rs - (line 14) ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/lib.rs - (line 14) stdout ----
[INFO] [stdout] error[E0277]: `Branch` doesn't implement `Debug`
[INFO] [stdout]  --> src/lib.rs:17:18
[INFO] [stdout]   |
[INFO] [stdout] 6 | println!("{:?}", r.branches());
[INFO] [stdout]   |                  ^^^^^^^^^^^^ `Branch` cannot be formatted using `{:?}` because it doesn't implement `Debug`
[INFO] [stdout]   |
[INFO] [stdout]   = help: the trait `Debug` is not implemented for `Branch`
[INFO] [stdout]   = note: required because of the requirements on the impl of `Debug` for `Vec<Branch>`
[INFO] [stdout]   = note: 1 redundant requirements hidden
[INFO] [stdout]   = note: required because of the requirements on the impl of `Debug` for `Result<Vec<Branch>, supergit::repo::GitError>`
[INFO] [stdout]   = note: required by `std::fmt::Debug::fmt`
[INFO] [stdout]   = note: this error originates in the macro `$crate::format_args_nl` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]  --> src/lib.rs:19:23
[INFO] [stdout]   |
[INFO] [stdout] 8 | let branch = r.branch("main").unwrap();
[INFO] [stdout]   |                       ^^^^^^
[INFO] [stdout]   |                       |
[INFO] [stdout]   |                       expected struct `String`, found `&str`
[INFO] [stdout]   |                       help: try using a conversion method: `"main".to_string()`
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `id` found for struct `supergit::Commit` in the current scope
[INFO] [stdout]   --> src/lib.rs:21:25
[INFO] [stdout]    |
[INFO] [stdout] 10 | println!("{}: {}", head.id(), head.summary().unwrap_or("".into()));
[INFO] [stdout]    |                         ^^-- help: remove the arguments
[INFO] [stdout]    |                         |
[INFO] [stdout]    |                         field, not a method
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `unwrap_or` found for struct `String` in the current scope
[INFO] [stdout]   --> src/lib.rs:21:46
[INFO] [stdout]    |
[INFO] [stdout] 10 | println!("{}: {}", head.id(), head.summary().unwrap_or("".into()));
[INFO] [stdout]    |                                              ^^^^^^^^^ method not found in `String`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0308, E0599.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/lib.rs - (line 14)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.34s
[INFO] [stdout] 
[INFO] [stderr] error: test failed, to rerun pass '--doc'
[INFO] running `Command { std: "docker" "inspect" "9fdc45ef76a3fde29ba76b8ea52d836d0c1ab8044b0e9498beee0e4b4872dc55", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9fdc45ef76a3fde29ba76b8ea52d836d0c1ab8044b0e9498beee0e4b4872dc55", kill_on_drop: false }`
[INFO] [stdout] 9fdc45ef76a3fde29ba76b8ea52d836d0c1ab8044b0e9498beee0e4b4872dc55