[INFO] cloning repository https://github.com/claytonweaver/leetcode_add_strings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/claytonweaver/leetcode_add_strings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fclaytonweaver%2Fleetcode_add_strings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fclaytonweaver%2Fleetcode_add_strings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c3cfe814d1862f4e75c080d26ccacb971dc888c6
[INFO] checking claytonweaver/leetcode_add_strings 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%2Fclaytonweaver%2Fleetcode_add_strings" "/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/claytonweaver/leetcode_add_strings
[INFO] finished tweaking git repo https://github.com/claytonweaver/leetcode_add_strings
[INFO] tweaked toml for git repo https://github.com/claytonweaver/leetcode_add_strings written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/claytonweaver/leetcode_add_strings 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/claytonweaver/leetcode_add_strings 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] 1318f44f0c3eed57fd94c0a65b99b9f8d675a58818724634acfab8eee63a378d
[INFO] running `Command { std: "docker" "start" "-a" "1318f44f0c3eed57fd94c0a65b99b9f8d675a58818724634acfab8eee63a378d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1318f44f0c3eed57fd94c0a65b99b9f8d675a58818724634acfab8eee63a378d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1318f44f0c3eed57fd94c0a65b99b9f8d675a58818724634acfab8eee63a378d", kill_on_drop: false }`
[INFO] [stdout] 1318f44f0c3eed57fd94c0a65b99b9f8d675a58818724634acfab8eee63a378d
[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] 3898442b99d38c9a08c9e95e248e70966706404b26fd425e5336363518754d01
[INFO] running `Command { std: "docker" "start" "-a" "3898442b99d38c9a08c9e95e248e70966706404b26fd425e5336363518754d01", kill_on_drop: false }`
[INFO] [stderr]     Checking add_strings v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `chars`
[INFO] [stdout]   --> src/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let chars = num_str.chars();
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<char, Infallible>
[INFO] [stdout]   --> src/main.rs:24:23
[INFO] [stdout]    |
[INFO] [stdout] 24 |         let c: char = arr[i].try_into().unwrap();
[INFO] [stdout]    |                       ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `chars`
[INFO] [stdout]   --> src/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let chars = num_str.chars();
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `add_strings` (bin "add_strings" 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<char, Infallible>
[INFO] [stdout]   --> src/main.rs:24:23
[INFO] [stdout]    |
[INFO] [stdout] 24 |         let c: char = arr[i].try_into().unwrap();
[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 `add_strings` (bin "add_strings") due to 1 previous error; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "3898442b99d38c9a08c9e95e248e70966706404b26fd425e5336363518754d01", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3898442b99d38c9a08c9e95e248e70966706404b26fd425e5336363518754d01", kill_on_drop: false }`
[INFO] [stdout] 3898442b99d38c9a08c9e95e248e70966706404b26fd425e5336363518754d01