[INFO] fetching crate arcstr 1.2.0...
[INFO] checking arcstr-1.2.0 against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] extracting crate arcstr 1.2.0 into /workspace/builds/worker-2-tc2/source
[INFO] started tweaking crates.io crate arcstr 1.2.0
[INFO] finished tweaking crates.io crate arcstr 1.2.0
[INFO] tweaked toml for crates.io crate arcstr 1.2.0 written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate arcstr 1.2.0 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] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 48 packages to latest compatible versions
[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-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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] 69bac18e17b2ab2d016fa49534b01112a4213cfb33b4343658717098604a3a96
[INFO] running `Command { std: "docker" "start" "-a" "69bac18e17b2ab2d016fa49534b01112a4213cfb33b4343658717098604a3a96", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "69bac18e17b2ab2d016fa49534b01112a4213cfb33b4343658717098604a3a96", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "69bac18e17b2ab2d016fa49534b01112a4213cfb33b4343658717098604a3a96", kill_on_drop: false }`
[INFO] [stdout] 69bac18e17b2ab2d016fa49534b01112a4213cfb33b4343658717098604a3a96
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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] 8a06cc4dae36e4b738e0098c1ce161ee3fe7a5752758847d0e342f5ef695cc38
[INFO] running `Command { std: "docker" "start" "-a" "8a06cc4dae36e4b738e0098c1ce161ee3fe7a5752758847d0e342f5ef695cc38", kill_on_drop: false }`
[INFO] [stderr]     Checking arcstr v1.2.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking serde_test v1.0.177
[INFO] [stdout] error: this type will no longer be must used: Result<ArcStr, Infallible>
[INFO] [stdout]     --> src/arc_str.rs:1561:53
[INFO] [stdout]      |
[INFO] [stdout] 1561 |       fn from_str(s: &str) -> Result<Self, Self::Err> {
[INFO] [stdout]      |  _____________________________________________________^
[INFO] [stdout] 1562 | |         Ok(Self::from(s))
[INFO] [stdout] 1563 | |     }
[INFO] [stdout]      | |_____^
[INFO] [stdout]      |
[INFO] [stdout]      = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<ArcStr, Infallible>
[INFO] [stdout]     --> src/arc_str.rs:1562:9
[INFO] [stdout]      |
[INFO] [stdout] 1562 |         Ok(Self::from(s))
[INFO] [stdout]      |         ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<Substr, Infallible>
[INFO] [stdout]    --> src/substr.rs:778:53
[INFO] [stdout]     |
[INFO] [stdout] 778 |       fn from_str(s: &str) -> Result<Self, Self::Err> {
[INFO] [stdout]     |  _____________________________________________________^
[INFO] [stdout] 779 | |         Ok(Self::from(ArcStr::from(s)))
[INFO] [stdout] 780 | |     }
[INFO] [stdout]     | |_____^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<Substr, Infallible>
[INFO] [stdout]    --> src/substr.rs:779:9
[INFO] [stdout]     |
[INFO] [stdout] 779 |         Ok(Self::from(ArcStr::from(s)))
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `arcstr` (lib) due to 4 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "8a06cc4dae36e4b738e0098c1ce161ee3fe7a5752758847d0e342f5ef695cc38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8a06cc4dae36e4b738e0098c1ce161ee3fe7a5752758847d0e342f5ef695cc38", kill_on_drop: false }`
[INFO] [stdout] 8a06cc4dae36e4b738e0098c1ce161ee3fe7a5752758847d0e342f5ef695cc38