[INFO] fetching crate mgrrs 0.1.0...
[INFO] checking mgrrs-0.1.0 against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] extracting crate mgrrs 0.1.0 into /workspace/builds/worker-7-tc2/source
[INFO] started tweaking crates.io crate mgrrs 0.1.0
[INFO] finished tweaking crates.io crate mgrrs 0.1.0
[INFO] tweaked toml for crates.io crate mgrrs 0.1.0 written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate mgrrs 0.1.0 on toolchain 4f260f0f20b3133d20cfb50353c0221943af5796
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate mgrrs 0.1.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 31654a183e2f7c46fd1bb0c6d78ee8884849e97eaec7e07ca58d894fea096bff
[INFO] running `Command { std: "docker" "start" "-a" "31654a183e2f7c46fd1bb0c6d78ee8884849e97eaec7e07ca58d894fea096bff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "31654a183e2f7c46fd1bb0c6d78ee8884849e97eaec7e07ca58d894fea096bff", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31654a183e2f7c46fd1bb0c6d78ee8884849e97eaec7e07ca58d894fea096bff", kill_on_drop: false }`
[INFO] [stdout] 31654a183e2f7c46fd1bb0c6d78ee8884849e97eaec7e07ca58d894fea096bff
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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 -Dunmustuse_in_always_ok" "-e" "RUSTDOCFLAGS=--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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0a419f1bd412bf80a36f552c058fa307428b1836434a866e2f9649684d318fc4
[INFO] running `Command { std: "docker" "start" "-a" "0a419f1bd412bf80a36f552c058fa307428b1836434a866e2f9649684d318fc4", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.8
[INFO] [stderr]    Compiling cc v1.0.47
[INFO] [stderr]    Compiling failure_derive v0.1.6
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling getrandom v0.1.13
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]     Checking clicolors-control v1.0.1
[INFO] [stderr]     Checking termios v0.3.1
[INFO] [stderr]     Checking ppv-lite86 v0.2.6
[INFO] [stderr]    Compiling escargot v0.3.1
[INFO] [stderr]     Checking number_prefix v0.3.0
[INFO] [stderr]     Checking remove_dir_all v0.5.2
[INFO] [stderr]     Checking console v0.9.1
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.32
[INFO] [stderr]     Checking c2-chacha v0.2.3
[INFO] [stderr]     Checking indicatif v0.13.0
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking predicates v1.0.1
[INFO] [stderr]     Checking tempfile v3.1.0
[INFO] [stderr]     Checking backtrace v0.3.40
[INFO] [stderr]    Compiling structopt-derive v0.2.18
[INFO] [stderr]    Compiling synstructure v0.12.2
[INFO] [stderr]    Compiling serde_derive v1.0.102
[INFO] [stderr]     Checking structopt v0.2.18
[INFO] [stderr]     Checking failure v0.1.6
[INFO] [stderr]     Checking exitfailure v0.5.1
[INFO] [stderr]     Checking mgrrs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/lib.rs:4:13
[INFO] [stdout]   |
[INFO] [stdout] 4 |             writeln!(writer, "{}", line);
[INFO] [stdout]   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]   |
[INFO] [stdout] 4 |             let _ = writeln!(writer, "{}", line);
[INFO] [stdout]   |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<String, Infallible>
[INFO] [stdout]  --> src/main.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 7 | #[derive(StructOpt)]
[INFO] [stdout]   |          ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout]   = note: this error originates in the derive macro `StructOpt` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `mgrrs` (bin "mgrrs") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "0a419f1bd412bf80a36f552c058fa307428b1836434a866e2f9649684d318fc4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0a419f1bd412bf80a36f552c058fa307428b1836434a866e2f9649684d318fc4", kill_on_drop: false }`
[INFO] [stdout] 0a419f1bd412bf80a36f552c058fa307428b1836434a866e2f9649684d318fc4