[INFO] fetching crate sudokugen 0.3.1...
[INFO] checking sudokugen-0.3.1 against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] extracting crate sudokugen 0.3.1 into /workspace/builds/worker-2-tc1/source
[INFO] validating manifest of crates.io crate sudokugen 0.3.1 on toolchain ceab6128fa48a616bfd3e3adf4bc80133b8ee223
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate sudokugen 0.3.1
[INFO] finished tweaking crates.io crate sudokugen 0.3.1
[INFO] tweaked toml for crates.io crate sudokugen 0.3.1 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 67 packages
[INFO] [stderr]       Adding bitflags v1.3.2 (latest: v2.5.0)
[INFO] [stderr]       Adding clap v2.34.0 (latest: v4.5.4)
[INFO] [stderr]       Adding criterion v0.3.6 (latest: v0.5.1)
[INFO] [stderr]       Adding criterion-plot v0.4.5 (latest: v0.5.0)
[INFO] [stderr]       Adding half v1.8.3 (latest: v2.4.0)
[INFO] [stderr]       Adding hermit-abi v0.1.19 (latest: v0.3.9)
[INFO] [stderr]       Adding itertools v0.10.5 (latest: v0.12.1)
[INFO] [stderr]       Adding textwrap v0.11.0 (latest: v0.16.1)
[INFO] [stderr]       Adding wasi v0.11.0+wasi-snapshot-preview1 (latest: v0.13.0+wasi-0.2.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6f7d0fd4f5db3fcc715107acb43a1a0ac624682b6cb4491280cf5f1f8780b5ac
[INFO] running `Command { std: "docker" "start" "-a" "6f7d0fd4f5db3fcc715107acb43a1a0ac624682b6cb4491280cf5f1f8780b5ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6f7d0fd4f5db3fcc715107acb43a1a0ac624682b6cb4491280cf5f1f8780b5ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6f7d0fd4f5db3fcc715107acb43a1a0ac624682b6cb4491280cf5f1f8780b5ac", kill_on_drop: false }`
[INFO] [stdout] 6f7d0fd4f5db3fcc715107acb43a1a0ac624682b6cb4491280cf5f1f8780b5ac
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 58468dc6cb876e4f38796da4fc67ab25c1e503b8f34aa850cf811f72cc4842bd
[INFO] running `Command { std: "docker" "start" "-a" "58468dc6cb876e4f38796da4fc67ab25c1e503b8f34aa850cf811f72cc4842bd", kill_on_drop: false }`
[INFO] [stderr]     Checking criterion v0.3.6
[INFO] [stderr]     Checking sudokugen v0.3.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `TryInto` is imported redundantly
[INFO] [stdout]   --> src/board.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | use std::convert::TryInto;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   --> /rustc/ceab6128fa48a616bfd3e3adf4bc80133b8ee223/library/std/src/prelude/mod.rs:148:13
[INFO] [stdout]    |
[INFO] [stdout]    = note: the item `TryInto` is already defined here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `block` is never read
[INFO] [stdout]   --> src/solver/candidate_cache.rs:62:9
[INFO] [stdout]    |
[INFO] [stdout] 60 | pub struct Candidates<'a> {
[INFO] [stdout]    |            ---------- field in this struct
[INFO] [stdout] 61 |     pub value: &'a u8,
[INFO] [stdout] 62 |     pub block: &'a Block,
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `TryInto` is imported redundantly
[INFO] [stdout]   --> src/board.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | use std::convert::TryInto;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   --> /rustc/ceab6128fa48a616bfd3e3adf4bc80133b8ee223/library/std/src/prelude/mod.rs:148:13
[INFO] [stdout]    |
[INFO] [stdout]    = note: the item `TryInto` is already defined here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `block` is never read
[INFO] [stdout]   --> src/solver/candidate_cache.rs:62:9
[INFO] [stdout]    |
[INFO] [stdout] 60 | pub struct Candidates<'a> {
[INFO] [stdout]    |            ---------- field in this struct
[INFO] [stdout] 61 |     pub value: &'a u8,
[INFO] [stdout] 62 |     pub block: &'a Block,
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.10s
[INFO] running `Command { std: "docker" "inspect" "58468dc6cb876e4f38796da4fc67ab25c1e503b8f34aa850cf811f72cc4842bd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "58468dc6cb876e4f38796da4fc67ab25c1e503b8f34aa850cf811f72cc4842bd", kill_on_drop: false }`
[INFO] [stdout] 58468dc6cb876e4f38796da4fc67ab25c1e503b8f34aa850cf811f72cc4842bd