[INFO] cloning repository https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/BenSandeen/sudoku-hinter-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 02a14a4d9e64deede268ed1df6b10ac0efb67e03
[INFO] checking BenSandeen/sudoku-hinter-rs against try#44f3504e96c944ae54fc72b5f5008f53f7eda001 for pr-136776
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBenSandeen%2Fsudoku-hinter-rs" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/BenSandeen/sudoku-hinter-rs on toolchain 44f3504e96c944ae54fc72b5f5008f53f7eda001
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] finished tweaking git repo https://github.com/BenSandeen/sudoku-hinter-rs
[INFO] tweaked toml for git repo https://github.com/BenSandeen/sudoku-hinter-rs written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/BenSandeen/sudoku-hinter-rs 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" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "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@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e866cfe8a03c3ec2234b96bc93253623380a099abcff098ffd63a78b1d6b45c8
[INFO] running `Command { std: "docker" "start" "-a" "e866cfe8a03c3ec2234b96bc93253623380a099abcff098ffd63a78b1d6b45c8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e866cfe8a03c3ec2234b96bc93253623380a099abcff098ffd63a78b1d6b45c8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e866cfe8a03c3ec2234b96bc93253623380a099abcff098ffd63a78b1d6b45c8", kill_on_drop: false }`
[INFO] [stdout] e866cfe8a03c3ec2234b96bc93253623380a099abcff098ffd63a78b1d6b45c8
[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" "-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@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+44f3504e96c944ae54fc72b5f5008f53f7eda001" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2571ff010fdbab14c4fbef0684fc77540081d46fef51185fb16409b116797c26
[INFO] running `Command { std: "docker" "start" "-a" "2571ff010fdbab14c4fbef0684fc77540081d46fef51185fb16409b116797c26", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling libc v0.2.74
[INFO] [stderr]    Compiling syn v1.0.38
[INFO] [stderr]    Compiling serde_derive v1.0.115
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling serde v1.0.115
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking ppv-lite86 v0.2.8
[INFO] [stderr]     Checking itoa v0.4.6
[INFO] [stderr]     Checking csv-core v0.1.10
[INFO] [stderr]     Checking regex-automata v0.1.9
[INFO] [stderr]     Checking rand_core v0.5.1
[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 bstr v0.2.13
[INFO] [stderr]     Checking csv v1.1.3
[INFO] [stderr]     Checking sudoku-hinter-rs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `BorrowMut`
[INFO] [stdout]  --> src/main.rs:5:19
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::borrow::{BorrowMut, Borrow};
[INFO] [stdout]   |                   ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Rem`
[INFO] [stdout]   --> src/main.rs:10:33
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::ops::{Index, IndexMut, Rem};
[INFO] [stdout]    |                                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `BorrowMut`
[INFO] [stdout]  --> src/main.rs:5:19
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::borrow::{BorrowMut, Borrow};
[INFO] [stdout]   |                   ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Rem`
[INFO] [stdout]   --> src/main.rs:10:33
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::ops::{Index, IndexMut, Rem};
[INFO] [stdout]    |                                 ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut rng = rand::thread_rng();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ii`
[INFO] [stdout]    --> src/main.rs:359:14
[INFO] [stdout]     |
[INFO] [stdout] 359 |         for (ii, row) in self.board.iter().enumerate() {
[INFO] [stdout]     |              ^^ help: if this is intentional, prefix it with an underscore: `_ii`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `jj`
[INFO] [stdout]    --> src/main.rs:361:18
[INFO] [stdout]     |
[INFO] [stdout] 361 |             for (jj, col) in row.iter().enumerate() {
[INFO] [stdout]     |                  ^^ help: if this is intentional, prefix it with an underscore: `_jj`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `has_unique_elements` is never used
[INFO] [stdout]   --> src/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn has_unique_elements<T>(iter: T) -> bool
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `check_intermediate_puzzle` is never used
[INFO] [stdout]    --> src/main.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 67  | impl Board{
[INFO] [stdout]     | ---------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 246 |     fn check_intermediate_puzzle(&self, last_modified_cell: Cell) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:184:17
[INFO] [stdout]     |
[INFO] [stdout] 184 |                 &self.solve(Cell{row: (&cell).row, col: (&cell).col}, rng);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 184 |                 let _ = &self.solve(Cell{row: (&cell).row, col: (&cell).col}, rng);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: call to `.borrow()` on a reference in this situation does nothing
[INFO] [stdout]    --> src/main.rs:267:27
[INFO] [stdout]     |
[INFO] [stdout] 267 |             let col = self.borrow().get_col(col_idx);
[INFO] [stdout]     |                           ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: the type `Board` does not implement `Borrow`, so calling `borrow` on `&Board` copies the reference, which does not do anything and can be removed
[INFO] [stdout]     = note: `#[warn(noop_method_call)]` on by default
[INFO] [stdout] help: remove this redundant call
[INFO] [stdout]     |
[INFO] [stdout] 267 -             let col = self.borrow().get_col(col_idx);
[INFO] [stdout] 267 +             let col = self.get_col(col_idx);
[INFO] [stdout]     |
[INFO] [stdout] help: if you meant to clone `Board`, implement `Clone` for it
[INFO] [stdout]     |
[INFO] [stdout] 58  + #[derive(Clone)]
[INFO] [stdout] 59  | struct Board {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:360:13
[INFO] [stdout]     |
[INFO] [stdout] 360 |             write!(f, "\n");
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:362:17
[INFO] [stdout]     |
[INFO] [stdout] 362 |                 write!(f, " {} ", *col);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut rng = rand::thread_rng();
[INFO] [stdout]    |         ----^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ii`
[INFO] [stdout]    --> src/main.rs:359:14
[INFO] [stdout]     |
[INFO] [stdout] 359 |         for (ii, row) in self.board.iter().enumerate() {
[INFO] [stdout]     |              ^^ help: if this is intentional, prefix it with an underscore: `_ii`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `jj`
[INFO] [stdout]    --> src/main.rs:361:18
[INFO] [stdout]     |
[INFO] [stdout] 361 |             for (jj, col) in row.iter().enumerate() {
[INFO] [stdout]     |                  ^^ help: if this is intentional, prefix it with an underscore: `_jj`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `has_unique_elements` is never used
[INFO] [stdout]   --> src/main.rs:42:4
[INFO] [stdout]    |
[INFO] [stdout] 42 | fn has_unique_elements<T>(iter: T) -> bool
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `check_intermediate_puzzle` is never used
[INFO] [stdout]    --> src/main.rs:246:8
[INFO] [stdout]     |
[INFO] [stdout] 67  | impl Board{
[INFO] [stdout]     | ---------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 246 |     fn check_intermediate_puzzle(&self, last_modified_cell: Cell) -> bool {
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:184:17
[INFO] [stdout]     |
[INFO] [stdout] 184 |                 &self.solve(Cell{row: (&cell).row, col: (&cell).col}, rng);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 184 |                 let _ = &self.solve(Cell{row: (&cell).row, col: (&cell).col}, rng);
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: call to `.borrow()` on a reference in this situation does nothing
[INFO] [stdout]    --> src/main.rs:267:27
[INFO] [stdout]     |
[INFO] [stdout] 267 |             let col = self.borrow().get_col(col_idx);
[INFO] [stdout]     |                           ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: the type `Board` does not implement `Borrow`, so calling `borrow` on `&Board` copies the reference, which does not do anything and can be removed
[INFO] [stdout]     = note: `#[warn(noop_method_call)]` on by default
[INFO] [stdout] help: remove this redundant call
[INFO] [stdout]     |
[INFO] [stdout] 267 -             let col = self.borrow().get_col(col_idx);
[INFO] [stdout] 267 +             let col = self.get_col(col_idx);
[INFO] [stdout]     |
[INFO] [stdout] help: if you meant to clone `Board`, implement `Clone` for it
[INFO] [stdout]     |
[INFO] [stdout] 58  + #[derive(Clone)]
[INFO] [stdout] 59  | struct Board {
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:360:13
[INFO] [stdout]     |
[INFO] [stdout] 360 |             write!(f, "\n");
[INFO] [stdout]     |             ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:362:17
[INFO] [stdout]     |
[INFO] [stdout] 362 |                 write!(f, " {} ", *col);
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 17.41s
[INFO] running `Command { std: "docker" "inspect" "2571ff010fdbab14c4fbef0684fc77540081d46fef51185fb16409b116797c26", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2571ff010fdbab14c4fbef0684fc77540081d46fef51185fb16409b116797c26", kill_on_drop: false }`
[INFO] [stdout] 2571ff010fdbab14c4fbef0684fc77540081d46fef51185fb16409b116797c26
