[INFO] fetching crate idiom-solitaire 0.1.0...
[INFO] checking idiom-solitaire-0.1.0 against master#c5fbcd35a8217a17f6b63a22217ace06cf8f5f02 for pr-86194
[INFO] extracting crate idiom-solitaire 0.1.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate idiom-solitaire 0.1.0 on toolchain c5fbcd35a8217a17f6b63a22217ace06cf8f5f02
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate idiom-solitaire 0.1.0
[INFO] finished tweaking crates.io crate idiom-solitaire 0.1.0
[INFO] tweaked toml for crates.io crate idiom-solitaire 0.1.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] aa88c2de2604070891d93015bf6b0c66ad520b8a2de1b7737af502726530e3f5
[INFO] running `Command { std: "docker" "start" "-a" "aa88c2de2604070891d93015bf6b0c66ad520b8a2de1b7737af502726530e3f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aa88c2de2604070891d93015bf6b0c66ad520b8a2de1b7737af502726530e3f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aa88c2de2604070891d93015bf6b0c66ad520b8a2de1b7737af502726530e3f5", kill_on_drop: false }`
[INFO] [stdout] aa88c2de2604070891d93015bf6b0c66ad520b8a2de1b7737af502726530e3f5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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" "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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+c5fbcd35a8217a17f6b63a22217ace06cf8f5f02" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bf2523477b9446468f70f204e523e72f68b2396b92d092e81491fe07193bf919
[INFO] running `Command { std: "docker" "start" "-a" "bf2523477b9446468f70f204e523e72f68b2396b92d092e81491fe07193bf919", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.27
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling serde_derive v1.0.126
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]    Compiling serde v1.0.126
[INFO] [stderr]    Compiling pinyin v0.8.0
[INFO] [stderr]     Checking regex-automata v0.1.10
[INFO] [stderr]     Checking ppv-lite86 v0.2.10
[INFO] [stderr]     Checking hashbrown v0.9.1
[INFO] [stderr]     Checking itoa v0.4.7
[INFO] [stderr]     Checking fixedbitset v0.4.0
[INFO] [stderr]    Compiling indexmap v1.6.2
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_pcg v0.2.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]    Compiling syn v1.0.73
[INFO] [stderr]     Checking pathfinding v2.1.5
[INFO] [stderr]     Checking bstr v0.2.16
[INFO] [stderr]     Checking csv v1.1.6
[INFO] [stderr]     Checking idiom-solitaire v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0412]: cannot find type `NoneError` in module `std::option`
[INFO] [stdout]   --> src/errors.rs:23:24
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl From<std::option::NoneError> for Error {
[INFO] [stdout]    |                        ^^^^^^^^^ not found in `std::option`
[INFO] [stdout]    |
[INFO] [stdout] help: there is an enum variant `crate::Error::NoneError`; try using the variant's enum
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl From<crate::Error> for Error {
[INFO] [stdout]    |           ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0412]: cannot find type `NoneError` in module `std::option`
[INFO] [stdout]   --> src/errors.rs:24:29
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn from(_: std::option::NoneError) -> Self {
[INFO] [stdout]    |                             ^^^^^^^^^ not found in `std::option`
[INFO] [stdout]    |
[INFO] [stdout] help: there is an enum variant `crate::Error::NoneError`; try using the variant's enum
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn from(_: crate::Error) -> Self {
[INFO] [stdout]    |                ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0412]: cannot find type `NoneError` in module `std::option`
[INFO] [stdout]   --> src/errors.rs:23:24
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl From<std::option::NoneError> for Error {
[INFO] [stdout]    |                        ^^^^^^^^^ not found in `std::option`
[INFO] [stdout]    |
[INFO] [stdout] help: there is an enum variant `crate::Error::NoneError`; try using the variant's enum
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl From<crate::Error> for Error {
[INFO] [stdout]    |           ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0412]: cannot find type `NoneError` in module `std::option`
[INFO] [stdout]   --> src/errors.rs:24:29
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn from(_: std::option::NoneError) -> Self {
[INFO] [stdout]    |                             ^^^^^^^^^ not found in `std::option`
[INFO] [stdout]    |
[INFO] [stdout] help: there is an enum variant `crate::Error::NoneError`; try using the variant's enum
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn from(_: crate::Error) -> Self {
[INFO] [stdout]    |                ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:96:55
[INFO] [stdout]     |
[INFO] [stdout] 91  | /     pub fn solve_random(&mut self, input: &str) -> Result<Idiom> {
[INFO] [stdout] 92  | |         if let Some(s) = self.state.get_mut(&self.get_key(input)) {
[INFO] [stdout] 93  | |             if s.is_empty() {
[INFO] [stdout] 94  | |                 return Err(SolitaireNotFound);
[INFO] [stdout] 95  | |             }
[INFO] [stdout] 96  | |             let i = (0..s.len()).choose(&mut self.rng)?;
[INFO] [stdout]     | |                                                       ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 99  | |         Err(SolitaireNotFound)
[INFO] [stdout] 100 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:104:43
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout]     | |                                           ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:107:54
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] 106 | |             SolitaireMode::Character => target.to_string(),
[INFO] [stdout] 107 | |             SolitaireMode::Tone => target.to_pinyin()?.with_tone().to_string(),
[INFO] [stdout]     | |                                                      ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:108:55
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 108 | |             SolitaireMode::Sound => target.to_pinyin()?.plain().to_string(),
[INFO] [stdout]     | |                                                       ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:110:95
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 110 | |         let result = bfs(&first, |p| self.successors(p), |p| self.get_key(&p.idiom) == target)?;
[INFO] [stdout]     | |                                                                                               ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:133:57
[INFO] [stdout]     |
[INFO] [stdout] 114 | /     pub fn solve_greedy(&mut self, input: &str) -> Result<Idiom> {
[INFO] [stdout] 115 | |         let s = match self.state.get(&self.get_key(input)) {
[INFO] [stdout] 116 | |             Some(s) => s,
[INFO] [stdout] 117 | |             None => return Err(SolitaireNotFound),
[INFO] [stdout] ...   |
[INFO] [stdout] 133 | |         let s = self.state.get_mut(&self.get_key(input))?;
[INFO] [stdout]     | |                                                         ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout] 134 | |         return Ok(s.swap_remove(max));
[INFO] [stdout] 135 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 8 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0412.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `idiom-solitaire`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:96:55
[INFO] [stdout]     |
[INFO] [stdout] 91  | /     pub fn solve_random(&mut self, input: &str) -> Result<Idiom> {
[INFO] [stdout] 92  | |         if let Some(s) = self.state.get_mut(&self.get_key(input)) {
[INFO] [stdout] 93  | |             if s.is_empty() {
[INFO] [stdout] 94  | |                 return Err(SolitaireNotFound);
[INFO] [stdout] 95  | |             }
[INFO] [stdout] 96  | |             let i = (0..s.len()).choose(&mut self.rng)?;
[INFO] [stdout]     | |                                                       ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 99  | |         Err(SolitaireNotFound)
[INFO] [stdout] 100 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:104:43
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout]     | |                                           ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:107:54
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] 106 | |             SolitaireMode::Character => target.to_string(),
[INFO] [stdout] 107 | |             SolitaireMode::Tone => target.to_pinyin()?.with_tone().to_string(),
[INFO] [stdout]     | |                                                      ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:108:55
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 108 | |             SolitaireMode::Sound => target.to_pinyin()?.plain().to_string(),
[INFO] [stdout]     | |                                                       ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] ...   |
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:110:95
[INFO] [stdout]     |
[INFO] [stdout] 102 | /     pub fn solve_target(&mut self, input: &str, target: &str) -> Result<Vec<Idiom>> {
[INFO] [stdout] 103 | |         let first = Idiom::from(input);
[INFO] [stdout] 104 | |         let target = target.chars().next()?;
[INFO] [stdout] 105 | |         let target = match self.mode {
[INFO] [stdout] ...   |
[INFO] [stdout] 110 | |         let result = bfs(&first, |p| self.successors(p), |p| self.get_key(&p.idiom) == target)?;
[INFO] [stdout]     | |                                                                                               ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout] 111 | |         Ok(result)
[INFO] [stdout] 112 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Vec<Idiom>, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a method that returns `Result`
[INFO] [stdout]    --> src/solver/mod.rs:133:57
[INFO] [stdout]     |
[INFO] [stdout] 114 | /     pub fn solve_greedy(&mut self, input: &str) -> Result<Idiom> {
[INFO] [stdout] 115 | |         let s = match self.state.get(&self.get_key(input)) {
[INFO] [stdout] 116 | |             Some(s) => s,
[INFO] [stdout] 117 | |             None => return Err(SolitaireNotFound),
[INFO] [stdout] ...   |
[INFO] [stdout] 133 | |         let s = self.state.get_mut(&self.get_key(input))?;
[INFO] [stdout]     | |                                                         ^ use `.ok_or(...)?` to provide an error compatible with `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout] 134 | |         return Ok(s.swap_remove(max));
[INFO] [stdout] 135 | |     }
[INFO] [stdout]     | |_____- this function returns a `Result`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<std::option::Option<Infallible>>` is not implemented for `std::result::Result<Idiom, errors::Error>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 8 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0412.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "bf2523477b9446468f70f204e523e72f68b2396b92d092e81491fe07193bf919", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bf2523477b9446468f70f204e523e72f68b2396b92d092e81491fe07193bf919", kill_on_drop: false }`
[INFO] [stdout] bf2523477b9446468f70f204e523e72f68b2396b92d092e81491fe07193bf919