[INFO] cloning repository https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fblack16/fractal_generator_rust_allegro" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 315f27ecabc7247880f26be83a58fe2b466ccebc
[INFO] checking fblack16/fractal_generator_rust_allegro against try#1f5783cbeb5da8b38566d718631d016891e9c912 for pr-142704
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fblack16/fractal_generator_rust_allegro on toolchain 1f5783cbeb5da8b38566d718631d016891e9c912
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] finished tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] tweaked toml for git repo https://github.com/fblack16/fractal_generator_rust_allegro written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/fblack16/fractal_generator_rust_allegro 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" "+1f5783cbeb5da8b38566d718631d016891e9c912" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking fblack16/fractal_generator_rust_allegro against try#1f5783cbeb5da8b38566d718631d016891e9c912 for pr-142704
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fblack16/fractal_generator_rust_allegro on toolchain 1f5783cbeb5da8b38566d718631d016891e9c912
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] finished tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] tweaked toml for git repo https://github.com/fblack16/fractal_generator_rust_allegro written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/fblack16/fractal_generator_rust_allegro 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" "+1f5783cbeb5da8b38566d718631d016891e9c912" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking fblack16/fractal_generator_rust_allegro against try#1f5783cbeb5da8b38566d718631d016891e9c912 for pr-142704
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fblack16/fractal_generator_rust_allegro on toolchain 1f5783cbeb5da8b38566d718631d016891e9c912
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] finished tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] tweaked toml for git repo https://github.com/fblack16/fractal_generator_rust_allegro written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/fblack16/fractal_generator_rust_allegro 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" "+1f5783cbeb5da8b38566d718631d016891e9c912" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking fblack16/fractal_generator_rust_allegro against try#1f5783cbeb5da8b38566d718631d016891e9c912 for pr-142704
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffblack16%2Ffractal_generator_rust_allegro" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fblack16/fractal_generator_rust_allegro on toolchain 1f5783cbeb5da8b38566d718631d016891e9c912
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] finished tweaking git repo https://github.com/fblack16/fractal_generator_rust_allegro
[INFO] tweaked toml for git repo https://github.com/fblack16/fractal_generator_rust_allegro written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/fblack16/fractal_generator_rust_allegro 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" "+1f5783cbeb5da8b38566d718631d016891e9c912" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded allegro-sys v0.0.43
[INFO] [stderr]   Downloaded allegro_util v0.0.43
[INFO] [stderr]   Downloaded allegro_primitives-sys v0.0.43
[INFO] [stderr]   Downloaded allegro_primitives v0.0.43
[INFO] [stderr]   Downloaded allegro v0.0.43
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] fc8c0c8e9b47cf39cce097cac1b4d8a19afc659d96a97e6ad73df5472fa0c941
[INFO] running `Command { std: "docker" "start" "-a" "fc8c0c8e9b47cf39cce097cac1b4d8a19afc659d96a97e6ad73df5472fa0c941", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fc8c0c8e9b47cf39cce097cac1b4d8a19afc659d96a97e6ad73df5472fa0c941", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fc8c0c8e9b47cf39cce097cac1b4d8a19afc659d96a97e6ad73df5472fa0c941", kill_on_drop: false }`
[INFO] [stdout] fc8c0c8e9b47cf39cce097cac1b4d8a19afc659d96a97e6ad73df5472fa0c941
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+1f5783cbeb5da8b38566d718631d016891e9c912" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 68b2f3e789a2cb2a4ab19af97ecfc066adddb4713f8a2831fa9c6a222423186f
[INFO] running `Command { std: "docker" "start" "-a" "68b2f3e789a2cb2a4ab19af97ecfc066adddb4713f8a2831fa9c6a222423186f", kill_on_drop: false }`
[INFO] [stderr]    Compiling allegro-sys v0.0.43
[INFO] [stderr]    Compiling libc v0.2.126
[INFO] [stderr]    Compiling allegro_primitives-sys v0.0.43
[INFO] [stderr]    Compiling allegro v0.0.43
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]    Compiling allegro_primitives v0.0.43
[INFO] [stderr]     Checking allegro_util v0.0.43
[INFO] [stderr]     Checking fractal_generator_rust_allegro v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `DerefMut` and `Deref`
[INFO] [stdout]  --> src/word.rs:2:16
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::ops::{Deref, DerefMut, Index, IndexMut};
[INFO] [stdout]   |                ^^^^^  ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `DerefMut` and `Deref`
[INFO] [stdout]  --> src/word.rs:2:16
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::ops::{Deref, DerefMut, Index, IndexMut};
[INFO] [stdout]   |                ^^^^^  ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `index`
[INFO] [stdout]    --> src/grammar.rs:105:14
[INFO] [stdout]     |
[INFO] [stdout] 105 |         for (index, rule) in production_rules.iter().enumerate() {
[INFO] [stdout]     |              ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `index`
[INFO] [stdout]    --> src/grammar.rs:105:14
[INFO] [stdout]     |
[INFO] [stdout] 105 |         for (index, rule) in production_rules.iter().enumerate() {
[INFO] [stdout]     |              ^^^^^ help: if this is intentional, prefix it with an underscore: `_index`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `primitives`
[INFO] [stdout]    --> src/main.rs:390:9
[INFO] [stdout]     |
[INFO] [stdout] 390 |     let primitives = PrimitivesAddon::init(&core).unwrap();
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_primitives`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `S` is never used
[INFO] [stdout]   --> src/main.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 | const S: f32 = 300.0;
[INFO] [stdout]    |       ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `lhs` and `rhs` are never read
[INFO] [stdout]   --> src/grammar.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | pub struct ProductionRule<T> {
[INFO] [stdout]    |            -------------- fields in this struct
[INFO] [stdout] 12 |     lhs: Word<T>,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 13 |     rhs: Word<T>,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `lhs`, and `rhs` are never used
[INFO] [stdout]   --> src/grammar.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 22 | impl<T> ProductionRule<T> {
[INFO] [stdout]    | ------------------------- associated items in this implementation
[INFO] [stdout] 23 |     pub fn new(lhs: Word<T>, rhs: Word<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 29 |     pub fn lhs(&self) -> &Word<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 32 |     pub fn rhs(&self) -> &Word<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `GrammarError` is never used
[INFO] [stdout]   --> src/grammar.rs:64:10
[INFO] [stdout]    |
[INFO] [stdout] 64 | pub enum GrammarError {
[INFO] [stdout]    |          ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `GrammarError` has derived impls for the traits `Debug` and `Clone`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Grammar` is never constructed
[INFO] [stdout]   --> src/grammar.rs:84:12
[INFO] [stdout]    |
[INFO] [stdout] 84 | pub struct Grammar<T>
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `validate_production_rules`, and `with_production_rules` are never used
[INFO] [stdout]    --> src/grammar.rs:97:12
[INFO] [stdout]     |
[INFO] [stdout] 93  | / impl<T> Grammar<T>
[INFO] [stdout] 94  | | where
[INFO] [stdout] 95  | |     T: PartialEq,
[INFO] [stdout]     | |_________________- associated items in this implementation
[INFO] [stdout] 96  |   {
[INFO] [stdout] 97  |       pub fn new(terminals: Vec<T>, non_terminals: Vec<T>) -> Self {
[INFO] [stdout]     |              ^^^
[INFO] [stdout] ...
[INFO] [stdout] 104 |       pub fn validate_production_rules(&self, production_rules: &[ProductionRule<T>]) -> Result<(), GrammarError> {
[INFO] [stdout]     |              ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 119 |       pub fn with_production_rules(self, production_rules: Vec<ProductionRule<T>>) -> Result<Self, GrammarError> {
[INFO] [stdout]     |              ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Letter` is never used
[INFO] [stdout]   --> src/check_this.rs:37:11
[INFO] [stdout]    |
[INFO] [stdout] 37 | pub trait Letter: Copy + PartialEq {}
[INFO] [stdout]    |           ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `primitives`
[INFO] [stdout]    --> src/main.rs:390:9
[INFO] [stdout]     |
[INFO] [stdout] 390 |     let primitives = PrimitivesAddon::init(&core).unwrap();
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_primitives`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `S` is never used
[INFO] [stdout]   --> src/main.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 | const S: f32 = 300.0;
[INFO] [stdout]    |       ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `lhs` and `rhs` are never read
[INFO] [stdout]   --> src/grammar.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | pub struct ProductionRule<T> {
[INFO] [stdout]    |            -------------- fields in this struct
[INFO] [stdout] 12 |     lhs: Word<T>,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 13 |     rhs: Word<T>,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `lhs`, and `rhs` are never used
[INFO] [stdout]   --> src/grammar.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 22 | impl<T> ProductionRule<T> {
[INFO] [stdout]    | ------------------------- associated items in this implementation
[INFO] [stdout] 23 |     pub fn new(lhs: Word<T>, rhs: Word<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 29 |     pub fn lhs(&self) -> &Word<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 32 |     pub fn rhs(&self) -> &Word<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `GrammarError` is never used
[INFO] [stdout]   --> src/grammar.rs:64:10
[INFO] [stdout]    |
[INFO] [stdout] 64 | pub enum GrammarError {
[INFO] [stdout]    |          ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `GrammarError` has derived impls for the traits `Debug` and `Clone`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Grammar` is never constructed
[INFO] [stdout]   --> src/grammar.rs:84:12
[INFO] [stdout]    |
[INFO] [stdout] 84 | pub struct Grammar<T>
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `validate_production_rules`, and `with_production_rules` are never used
[INFO] [stdout]    --> src/grammar.rs:97:12
[INFO] [stdout]     |
[INFO] [stdout] 93  | / impl<T> Grammar<T>
[INFO] [stdout] 94  | | where
[INFO] [stdout] 95  | |     T: PartialEq,
[INFO] [stdout]     | |_________________- associated items in this implementation
[INFO] [stdout] 96  |   {
[INFO] [stdout] 97  |       pub fn new(terminals: Vec<T>, non_terminals: Vec<T>) -> Self {
[INFO] [stdout]     |              ^^^
[INFO] [stdout] ...
[INFO] [stdout] 104 |       pub fn validate_production_rules(&self, production_rules: &[ProductionRule<T>]) -> Result<(), GrammarError> {
[INFO] [stdout]     |              ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 119 |       pub fn with_production_rules(self, production_rules: Vec<ProductionRule<T>>) -> Result<Self, GrammarError> {
[INFO] [stdout]     |              ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Letter` is never used
[INFO] [stdout]   --> src/check_this.rs:37:11
[INFO] [stdout]    |
[INFO] [stdout] 37 | pub trait Letter: Copy + PartialEq {}
[INFO] [stdout]    |           ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.10s
[INFO] running `Command { std: "docker" "inspect" "68b2f3e789a2cb2a4ab19af97ecfc066adddb4713f8a2831fa9c6a222423186f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "68b2f3e789a2cb2a4ab19af97ecfc066adddb4713f8a2831fa9c6a222423186f", kill_on_drop: false }`
[INFO] [stdout] 68b2f3e789a2cb2a4ab19af97ecfc066adddb4713f8a2831fa9c6a222423186f
