[INFO] fetching crate grrs-alec 0.1.0...
[INFO] checking grrs-alec-0.1.0 against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] extracting crate grrs-alec 0.1.0 into /workspace/builds/worker-3-tc2/source
[INFO] started tweaking crates.io crate grrs-alec 0.1.0
[INFO] finished tweaking crates.io crate grrs-alec 0.1.0
[INFO] tweaked toml for crates.io crate grrs-alec 0.1.0 written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate grrs-alec 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 grrs-alec 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-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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] 4115556df685478bab929a2c325dcbddb9dd8372419986037f1ac2a42ced5528
[INFO] running `Command { std: "docker" "start" "-a" "4115556df685478bab929a2c325dcbddb9dd8372419986037f1ac2a42ced5528", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4115556df685478bab929a2c325dcbddb9dd8372419986037f1ac2a42ced5528", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4115556df685478bab929a2c325dcbddb9dd8372419986037f1ac2a42ced5528", kill_on_drop: false }`
[INFO] [stdout] 4115556df685478bab929a2c325dcbddb9dd8372419986037f1ac2a42ced5528
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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] 459aa8a969ac2e2c5f75829ad72b1f1d011bbe300a41900aaa196b1512a102bb
[INFO] running `Command { std: "docker" "start" "-a" "459aa8a969ac2e2c5f75829ad72b1f1d011bbe300a41900aaa196b1512a102bb", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling proc-macro2 v1.0.5
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling cc v1.0.45
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling failure_derive v0.1.6
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]    Compiling unicode-segmentation v1.3.0
[INFO] [stderr]     Checking unicode-width v0.1.6
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking vec_map v0.8.1
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]     Checking atty v0.2.13
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling backtrace-sys v0.1.31
[INFO] [stderr]     Checking backtrace v0.3.38
[INFO] [stderr]    Compiling structopt-derive v0.2.18
[INFO] [stderr]    Compiling synstructure v0.12.1
[INFO] [stderr]     Checking structopt v0.2.18
[INFO] [stderr]     Checking failure v0.1.6
[INFO] [stderr]     Checking exitfailure v0.5.1
[INFO] [stderr]     Checking grrs-alec v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: this type will no longer be must used: Result<String, Infallible>
[INFO] [stdout]  --> src/main.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | #[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] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:28:7
[INFO] [stdout]    |
[INFO] [stdout] 28 |       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] 28 |       let _ = writeln!(writer, "{}", line);
[INFO] [stdout]    |       +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `grrs-alec` (bin "grrs-alec" test) due to 1 previous error; 1 warning emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error: this type will no longer be must used: Result<String, Infallible>
[INFO] [stdout]  --> src/main.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | #[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] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:28:7
[INFO] [stdout]    |
[INFO] [stdout] 28 |       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] 28 |       let _ = writeln!(writer, "{}", line);
[INFO] [stdout]    |       +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `grrs-alec` (bin "grrs-alec") due to 1 previous error; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "459aa8a969ac2e2c5f75829ad72b1f1d011bbe300a41900aaa196b1512a102bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "459aa8a969ac2e2c5f75829ad72b1f1d011bbe300a41900aaa196b1512a102bb", kill_on_drop: false }`
[INFO] [stdout] 459aa8a969ac2e2c5f75829ad72b1f1d011bbe300a41900aaa196b1512a102bb