[INFO] cloning repository https://github.com/phillipsj/learn-grss
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/phillipsj/learn-grss" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fphillipsj%2Flearn-grss", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fphillipsj%2Flearn-grss'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0081e3f733dfef00a7dd5cf4dc04ccc32b1dcad9
[INFO] checking phillipsj/learn-grss against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fphillipsj%2Flearn-grss" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/phillipsj/learn-grss
[INFO] finished tweaking git repo https://github.com/phillipsj/learn-grss
[INFO] tweaked toml for git repo https://github.com/phillipsj/learn-grss written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/phillipsj/learn-grss 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 git repo https://github.com/phillipsj/learn-grss 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-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] 27c9e4eae099633d1acc4ae1167440852d596cbba1d72918b9a44f4a99490a6c
[INFO] running `Command { std: "docker" "start" "-a" "27c9e4eae099633d1acc4ae1167440852d596cbba1d72918b9a44f4a99490a6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "27c9e4eae099633d1acc4ae1167440852d596cbba1d72918b9a44f4a99490a6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "27c9e4eae099633d1acc4ae1167440852d596cbba1d72918b9a44f4a99490a6c", kill_on_drop: false }`
[INFO] [stdout] 27c9e4eae099633d1acc4ae1167440852d596cbba1d72918b9a44f4a99490a6c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] e11843c8d033879dac750f37ca0bc707766a77f304eb5c69b31cbb90e3e7154e
[INFO] running `Command { std: "docker" "start" "-a" "e11843c8d033879dac750f37ca0bc707766a77f304eb5c69b31cbb90e3e7154e", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling syn v1.0.39
[INFO] [stderr]    Compiling libc v0.2.76
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]     Checking gimli v0.22.0
[INFO] [stderr]    Compiling serde_derive v1.0.115
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]     Checking miniz_oxide v0.4.1
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]    Compiling serde v1.0.115
[INFO] [stderr]     Checking object v0.20.0
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling serde_json v1.0.57
[INFO] [stderr]     Checking thread_local v1.0.1
[INFO] [stderr]    Compiling escargot v0.3.1
[INFO] [stderr]     Checking itoa v0.4.6
[INFO] [stderr]     Checking ppv-lite86 v0.2.9
[INFO] [stderr]     Checking regex-syntax v0.6.18
[INFO] [stderr]     Checking predicates-core v1.0.0
[INFO] [stderr]     Checking remove_dir_all v0.5.3
[INFO] [stderr]     Checking aho-corasick v0.7.13
[INFO] [stderr]     Checking predicates-tree v1.0.0
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking float-cmp v0.8.0
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking tempfile v3.1.0
[INFO] [stderr]     Checking regex v1.3.9
[INFO] [stderr]     Checking addr2line v0.13.0
[INFO] [stderr]     Checking backtrace v0.3.50
[INFO] [stderr]     Checking predicates v1.0.5
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling structopt-derive v0.4.9
[INFO] [stderr]     Checking failure v0.1.8
[INFO] [stderr]     Checking exitfailure v0.5.1
[INFO] [stderr]     Checking structopt v0.3.16
[INFO] [stderr]     Checking grss 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:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     pattern: String,
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `grss` (bin "grss") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "e11843c8d033879dac750f37ca0bc707766a77f304eb5c69b31cbb90e3e7154e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e11843c8d033879dac750f37ca0bc707766a77f304eb5c69b31cbb90e3e7154e", kill_on_drop: false }`
[INFO] [stdout] e11843c8d033879dac750f37ca0bc707766a77f304eb5c69b31cbb90e3e7154e