[INFO] cloning repository https://github.com/nrish/yams_rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nrish/yams_rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnrish%2Fyams_rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnrish%2Fyams_rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 2c2c0080ca6408b36a80237871747042ef79dd36
[INFO] building nrish/yams_rs against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnrish%2Fyams_rs" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nrish/yams_rs on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/nrish/yams_rs
[INFO] finished tweaking git repo https://github.com/nrish/yams_rs
[INFO] tweaked toml for git repo https://github.com/nrish/yams_rs written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/nrish/yams_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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 38f91566645f7c338eb5d9cf2e87231e3ee946297aad42e63e8021cbe2bd84bc
[INFO] running `Command { std: "docker" "start" "-a" "38f91566645f7c338eb5d9cf2e87231e3ee946297aad42e63e8021cbe2bd84bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "38f91566645f7c338eb5d9cf2e87231e3ee946297aad42e63e8021cbe2bd84bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "38f91566645f7c338eb5d9cf2e87231e3ee946297aad42e63e8021cbe2bd84bc", kill_on_drop: false }`
[INFO] [stdout] 38f91566645f7c338eb5d9cf2e87231e3ee946297aad42e63e8021cbe2bd84bc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 110088b5b048b653acba9d3cc439601fd8c1c5923fb3bcf42b201ff927dac982
[INFO] running `Command { std: "docker" "start" "-a" "110088b5b048b653acba9d3cc439601fd8c1c5923fb3bcf42b201ff927dac982", kill_on_drop: false }`
[INFO] [stderr]    Compiling yams v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::borrow::Borrow`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::borrow::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:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::num::ParseFloatError`
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::num::ParseFloatError;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::Index`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::ops::Index;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::slice`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::slice;
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::string::ParseError`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use std::string::ParseError;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::current`
[INFO] [stdout]   --> src/main.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | use std::thread::current;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `contained` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:108:5
[INFO] [stdout]     |
[INFO] [stdout] 108 |     contained,
[INFO] [stdout]     |     ^^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Contained`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `complete` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:109:5
[INFO] [stdout]     |
[INFO] [stdout] 109 |     complete,
[INFO] [stdout]     |     ^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Complete`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `unclosed` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:110:5
[INFO] [stdout]     |
[INFO] [stdout] 110 |     unclosed
[INFO] [stdout]     |     ^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Unclosed`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::BufRead`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::io::BufRead;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `statement`
[INFO] [stdout]   --> src/main.rs:24:17
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn evaluate(statement : Statement) -> f64{
[INFO] [stdout]    |                 ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_statement`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_value`
[INFO] [stdout]   --> src/main.rs:52:13
[INFO] [stdout]    |
[INFO] [stdout] 52 |         let num_value = match str.parse::<f64>(){
[INFO] [stdout]    |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 |     let mut chars : Vec<char> = str.chars().collect();
[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: `root_node`
[INFO] [stdout]    --> src/main.rs:218:9
[INFO] [stdout]     |
[INFO] [stdout] 218 |     let root_node = evaluate(statement_str).unwrap();
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_root_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Solver` is never constructed
[INFO] [stdout]   --> src/main.rs:17:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct Solver{
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `evaluate` is never used
[INFO] [stdout]   --> src/main.rs:24:8
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl Solver{
[INFO] [stdout]    | ----------- associated function in this implementation
[INFO] [stdout] 24 |     fn evaluate(statement : Statement) -> f64{
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `org_str`, `num_value`, `variable`, and `operator` are never read
[INFO] [stdout]   --> src/main.rs:35:5
[INFO] [stdout]    |
[INFO] [stdout] 31 | struct Value {
[INFO] [stdout]    |        ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 35 |     org_str: String,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 39 |     num_value : Option<f64>,
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     variable : Option<String>,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 47 |     operator : Option<char>
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `left`, `right`, and `value` are never read
[INFO] [stdout]   --> src/main.rs:92:5
[INFO] [stdout]    |
[INFO] [stdout] 91 | struct Node {
[INFO] [stdout]    |        ---- fields in this struct
[INFO] [stdout] 92 |     left: Option<Box<Node>>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 93 |     right: Option<Box<Node>>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 94 |     value: Value
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Statement` is never constructed
[INFO] [stdout]   --> src/main.rs:99:8
[INFO] [stdout]    |
[INFO] [stdout] 99 | struct Statement{
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `statement_string` is never used
[INFO] [stdout]    --> src/main.rs:202:4
[INFO] [stdout]     |
[INFO] [stdout] 202 | fn statement_string(node : &Node) -> String{
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: structure field `statementString` should have a snake case name
[INFO] [stdout]    --> src/main.rs:100:5
[INFO] [stdout]     |
[INFO] [stdout] 100 |     statementString : String,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `statement_string`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:216:5
[INFO] [stdout]     |
[INFO] [stdout] 216 |     stdin.read_line(&mut input_str);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 216 |     let _ = stdin.read_line(&mut input_str);
[INFO] [stdout]     |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.21s
[INFO] running `Command { std: "docker" "inspect" "110088b5b048b653acba9d3cc439601fd8c1c5923fb3bcf42b201ff927dac982", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "110088b5b048b653acba9d3cc439601fd8c1c5923fb3bcf42b201ff927dac982", kill_on_drop: false }`
[INFO] [stdout] 110088b5b048b653acba9d3cc439601fd8c1c5923fb3bcf42b201ff927dac982
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 71bd1d1e2b2c18fdaa52a9c705b37110f522fb1602b6e6e46ea92801326380af
[INFO] running `Command { std: "docker" "start" "-a" "71bd1d1e2b2c18fdaa52a9c705b37110f522fb1602b6e6e46ea92801326380af", kill_on_drop: false }`
[INFO] [stderr]    Compiling yams v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::borrow::Borrow`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::borrow::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:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::num::ParseFloatError`
[INFO] [stdout]  --> src/main.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::num::ParseFloatError;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::ops::Index`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::ops::Index;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::slice`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::slice;
[INFO] [stdout]    |     ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::string::ParseError`
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use std::string::ParseError;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::thread::current`
[INFO] [stdout]   --> src/main.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 | use std::thread::current;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `contained` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:108:5
[INFO] [stdout]     |
[INFO] [stdout] 108 |     contained,
[INFO] [stdout]     |     ^^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Contained`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `complete` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:109:5
[INFO] [stdout]     |
[INFO] [stdout] 109 |     complete,
[INFO] [stdout]     |     ^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Complete`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `unclosed` should have an upper camel case name
[INFO] [stdout]    --> src/main.rs:110:5
[INFO] [stdout]     |
[INFO] [stdout] 110 |     unclosed
[INFO] [stdout]     |     ^^^^^^^^ help: convert the identifier to upper camel case (notice the capitalization): `Unclosed`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::BufRead`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::io::BufRead;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `statement`
[INFO] [stdout]   --> src/main.rs:24:17
[INFO] [stdout]    |
[INFO] [stdout] 24 |     fn evaluate(statement : Statement) -> f64{
[INFO] [stdout]    |                 ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_statement`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_value`
[INFO] [stdout]   --> src/main.rs:52:13
[INFO] [stdout]    |
[INFO] [stdout] 52 |         let num_value = match str.parse::<f64>(){
[INFO] [stdout]    |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:148:9
[INFO] [stdout]     |
[INFO] [stdout] 148 |     let mut chars : Vec<char> = str.chars().collect();
[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: `root_node`
[INFO] [stdout]    --> src/main.rs:218:9
[INFO] [stdout]     |
[INFO] [stdout] 218 |     let root_node = evaluate(statement_str).unwrap();
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_root_node`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Solver` is never constructed
[INFO] [stdout]   --> src/main.rs:17:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct Solver{
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `evaluate` is never used
[INFO] [stdout]   --> src/main.rs:24:8
[INFO] [stdout]    |
[INFO] [stdout] 23 | impl Solver{
[INFO] [stdout]    | ----------- associated function in this implementation
[INFO] [stdout] 24 |     fn evaluate(statement : Statement) -> f64{
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `org_str`, `num_value`, `variable`, and `operator` are never read
[INFO] [stdout]   --> src/main.rs:35:5
[INFO] [stdout]    |
[INFO] [stdout] 31 | struct Value {
[INFO] [stdout]    |        ----- fields in this struct
[INFO] [stdout] ...
[INFO] [stdout] 35 |     org_str: String,
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 39 |     num_value : Option<f64>,
[INFO] [stdout]    |     ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     variable : Option<String>,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 47 |     operator : Option<char>
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `left`, `right`, and `value` are never read
[INFO] [stdout]   --> src/main.rs:92:5
[INFO] [stdout]    |
[INFO] [stdout] 91 | struct Node {
[INFO] [stdout]    |        ---- fields in this struct
[INFO] [stdout] 92 |     left: Option<Box<Node>>,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 93 |     right: Option<Box<Node>>,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 94 |     value: Value
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Statement` is never constructed
[INFO] [stdout]   --> src/main.rs:99:8
[INFO] [stdout]    |
[INFO] [stdout] 99 | struct Statement{
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `statement_string` is never used
[INFO] [stdout]    --> src/main.rs:202:4
[INFO] [stdout]     |
[INFO] [stdout] 202 | fn statement_string(node : &Node) -> String{
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: structure field `statementString` should have a snake case name
[INFO] [stdout]    --> src/main.rs:100:5
[INFO] [stdout]     |
[INFO] [stdout] 100 |     statementString : String,
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `statement_string`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:216:5
[INFO] [stdout]     |
[INFO] [stdout] 216 |     stdin.read_line(&mut input_str);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 216 |     let _ = stdin.read_line(&mut input_str);
[INFO] [stdout]     |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.18s
[INFO] running `Command { std: "docker" "inspect" "71bd1d1e2b2c18fdaa52a9c705b37110f522fb1602b6e6e46ea92801326380af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "71bd1d1e2b2c18fdaa52a9c705b37110f522fb1602b6e6e46ea92801326380af", kill_on_drop: false }`
[INFO] [stdout] 71bd1d1e2b2c18fdaa52a9c705b37110f522fb1602b6e6e46ea92801326380af