[INFO] fetching crate mr_cat 0.1.0...
[INFO] checking mr_cat-0.1.0 against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] extracting crate mr_cat 0.1.0 into /workspace/builds/worker-4-tc2/source
[INFO] started tweaking crates.io crate mr_cat 0.1.0
[INFO] removed 0 missing tests
[INFO] finished tweaking crates.io crate mr_cat 0.1.0
[INFO] tweaked toml for crates.io crate mr_cat 0.1.0 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate mr_cat 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 mr_cat 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-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] 113ce353214153b27077a0f9803c59a30e31aeabb4b0754aa2db9c581d0af3ed
[INFO] running `Command { std: "docker" "start" "-a" "113ce353214153b27077a0f9803c59a30e31aeabb4b0754aa2db9c581d0af3ed", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "113ce353214153b27077a0f9803c59a30e31aeabb4b0754aa2db9c581d0af3ed", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "113ce353214153b27077a0f9803c59a30e31aeabb4b0754aa2db9c581d0af3ed", kill_on_drop: false }`
[INFO] [stdout] 113ce353214153b27077a0f9803c59a30e31aeabb4b0754aa2db9c581d0af3ed
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] 496507dd2f8b5f305faf5af48a1a7dbce171accb821b1089517b7cfafdbc18b3
[INFO] running `Command { std: "docker" "start" "-a" "496507dd2f8b5f305faf5af48a1a7dbce171accb821b1089517b7cfafdbc18b3", kill_on_drop: false }`
[INFO] [stderr]     Checking memchr v2.7.5
[INFO] [stderr]     Checking predicates-core v1.0.9
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling doc-comment v0.3.3
[INFO] [stderr]    Compiling num-traits v0.2.19
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking difflib v0.4.0
[INFO] [stderr]    Compiling assert_cmd v2.0.17
[INFO] [stderr]     Checking termtree v0.5.1
[INFO] [stderr]     Checking is-terminal v0.4.16
[INFO] [stderr]     Checking wait-timeout v0.2.1
[INFO] [stderr]     Checking normalize-line-endings v0.3.0
[INFO] [stderr]    Compiling synstructure v0.12.6
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]     Checking colored v1.9.4
[INFO] [stderr]     Checking clap v2.34.0
[INFO] [stderr]     Checking predicates v3.1.3
[INFO] [stderr]     Checking predicates-tree v1.0.12
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]     Checking float-cmp v0.8.0
[INFO] [stderr]     Checking aho-corasick v1.1.3
[INFO] [stderr]     Checking object v0.36.7
[INFO] [stderr]     Checking regex-automata v0.4.9
[INFO] [stderr]    Compiling structopt-derive v0.2.18
[INFO] [stderr]     Checking structopt v0.2.18
[INFO] [stderr]     Checking regex v1.11.1
[INFO] [stderr]     Checking bstr v1.12.0
[INFO] [stderr]     Checking predicates v1.0.8
[INFO] [stderr]     Checking backtrace v0.3.75
[INFO] [stderr]     Checking failure v0.1.8
[INFO] [stderr]     Checking exitfailure v0.5.1
[INFO] [stderr]     Checking mr_cat 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:10:10
[INFO] [stdout]    |
[INFO] [stdout] 10 | #[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 `mr_cat` (bin "mr_cat") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused import: `io::stdout`
[INFO] [stdout]  --> tests/integration_tests.rs:3:11
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::{io::stdout, process::Command};
[INFO] [stdout]   |           ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<String, Infallible>
[INFO] [stdout]   --> src/main.rs:10:10
[INFO] [stdout]    |
[INFO] [stdout] 10 | #[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 `mr_cat` (bin "mr_cat" test) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "496507dd2f8b5f305faf5af48a1a7dbce171accb821b1089517b7cfafdbc18b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "496507dd2f8b5f305faf5af48a1a7dbce171accb821b1089517b7cfafdbc18b3", kill_on_drop: false }`
[INFO] [stdout] 496507dd2f8b5f305faf5af48a1a7dbce171accb821b1089517b7cfafdbc18b3