[INFO] cloning repository https://github.com/sczero/hello-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sczero/hello-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsczero%2Fhello-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsczero%2Fhello-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7466400dccfe6a13848578f8651c76b487f984f3
[INFO] checking sczero/hello-rust against try#3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsczero%2Fhello-rust" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sczero/hello-rust on toolchain 3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sczero/hello-rust
[INFO] finished tweaking git repo https://github.com/sczero/hello-rust
[INFO] tweaked toml for git repo https://github.com/sczero/hello-rust written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/sczero/hello-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 777807f96644b797e0a9c66a38bd678dae4767fe2f3102c1efd996f10e98ba5b
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "777807f96644b797e0a9c66a38bd678dae4767fe2f3102c1efd996f10e98ba5b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "777807f96644b797e0a9c66a38bd678dae4767fe2f3102c1efd996f10e98ba5b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "777807f96644b797e0a9c66a38bd678dae4767fe2f3102c1efd996f10e98ba5b", kill_on_drop: false }`
[INFO] [stdout] 777807f96644b797e0a9c66a38bd678dae4767fe2f3102c1efd996f10e98ba5b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 68a1cac522e804fbfe3c3242688bf218a1647127eb1ece6cbf440bc0746c51ae
[INFO] running `Command { std: "docker" "start" "-a" "68a1cac522e804fbfe3c3242688bf218a1647127eb1ece6cbf440bc0746c51ae", kill_on_drop: false }`
[INFO] [stderr]     Checking hello-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `Formatter`
[INFO] [stdout]  --> src/main.rs:2:32
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::fmt::{Debug, Display, Formatter};
[INFO] [stdout]   |                                ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ErrorKind`, `Error`
[INFO] [stdout]  --> src/main.rs:4:15
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::io::{Error, ErrorKind, Read};
[INFO] [stdout]   |               ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Formatter`
[INFO] [stdout]  --> src/main.rs:2:32
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::fmt::{Debug, Display, Formatter};
[INFO] [stdout]   |                                ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `ErrorKind`, `Error`
[INFO] [stdout]  --> src/main.rs:4:15
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::io::{Error, ErrorKind, Read};
[INFO] [stdout]   |               ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     let b = &a[..];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let x: i8 = 127;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let x = 5;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let x = 5.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let x = false;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let x = 'a';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let x = "HelloWorld";
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:27:9
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let x = "HelloWorld".to_string();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let x = (1, 1.0, "tuple");
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:29:9
[INFO] [stdout]    |
[INFO] [stdout] 29 |     let x = [1, 2, 3, 4, 5];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     let x = ["init value"; 10];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> src/main.rs:33:13
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let mut x = 1;
[INFO] [stdout]    |             ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let x = if x.len() > 5 {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/main.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |     let mut v: Vec<&str> = Vec::new();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:98:9
[INFO] [stdout]    |
[INFO] [stdout] 98 |     let x = &v[1];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:105:9
[INFO] [stdout]     |
[INFO] [stdout] 105 |     let x = &v[1..v.len()];
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]    --> src/main.rs:125:13
[INFO] [stdout]     |
[INFO] [stdout] 125 |     let mut v: Vec<Cell> = vec![Cell::Int(1), Cell::Text("宋诚中".to_string()), Cell::Float(20.0)];
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:128:13
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let mut x = String::new();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:129:13
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let mut x = "HelloWorld".to_string();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let x = a.to_string() + &b + &c;  // &String -> &str , &c -> &c[..] , c引用变为c切片
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:139:9
[INFO] [stdout]     |
[INFO] [stdout] 139 |     let x = format!("{}{}{}", a, b, c);
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:158:13
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let mut x: HashMap<String, i32> = HashMap::new();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `value`
[INFO] [stdout]    --> src/main.rs:169:9
[INFO] [stdout]     |
[INFO] [stdout] 169 |     let value = score["Hello1"];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]    --> src/main.rs:190:17
[INFO] [stdout]     |
[INFO] [stdout] 190 |             let result = f.read_to_string(&mut content).unwrap_or(0);
[INFO] [stdout]     |                 ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:224:35
[INFO] [stdout]     |
[INFO] [stdout] 224 |     fn some_function2<T: Summary>(s1: &T, s2: &T) {}
[INFO] [stdout]     |                                   ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:224:43
[INFO] [stdout]     |
[INFO] [stdout] 224 |     fn some_function2<T: Summary>(s1: &T, s2: &T) {}
[INFO] [stdout]     |                                           ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:225:47
[INFO] [stdout]     |
[INFO] [stdout] 225 |     fn some_function3<T: Summary, W: Summary>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                               ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:225:55
[INFO] [stdout]     |
[INFO] [stdout] 225 |     fn some_function3<T: Summary, W: Summary>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                                       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:226:47
[INFO] [stdout]     |
[INFO] [stdout] 226 |     fn some_function4<T: Summary, W: Display>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                               ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:226:55
[INFO] [stdout]     |
[INFO] [stdout] 226 |     fn some_function4<T: Summary, W: Display>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                                       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:227:23
[INFO] [stdout]     |
[INFO] [stdout] 227 |     fn some_function5(item: &(impl Summary + Display)) {}
[INFO] [stdout]     |                       ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:228:45
[INFO] [stdout]     |
[INFO] [stdout] 228 |     fn some_function6<T: Summary + Display>(item: &T) {}
[INFO] [stdout]     |                                             ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:229:61
[INFO] [stdout]     |
[INFO] [stdout] 229 |     fn some_function7<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) {}
[INFO] [stdout]     |                                                             ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/main.rs:229:68
[INFO] [stdout]     |
[INFO] [stdout] 229 |     fn some_function7<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) {}
[INFO] [stdout]     |                                                                    ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:230:29
[INFO] [stdout]     |
[INFO] [stdout] 230 |     fn some_function8<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                             ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/main.rs:230:36
[INFO] [stdout]     |
[INFO] [stdout] 230 |     fn some_function8<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                                    ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:10:9
[INFO] [stdout]    |
[INFO] [stdout] 10 |     let b = &a[..];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let x: i8 = 127;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let x = 5;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let x = 5.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let x = false;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let x = 'a';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let x = "HelloWorld";
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:27:9
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let x = "HelloWorld".to_string();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let x = (1, 1.0, "tuple");
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:29:9
[INFO] [stdout]    |
[INFO] [stdout] 29 |     let x = [1, 2, 3, 4, 5];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 |     let x = ["init value"; 10];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> src/main.rs:33:13
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let mut x = 1;
[INFO] [stdout]    |             ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let x = if x.len() > 5 {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/main.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |     let mut v: Vec<&str> = Vec::new();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:98:9
[INFO] [stdout]    |
[INFO] [stdout] 98 |     let x = &v[1];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:105:9
[INFO] [stdout]     |
[INFO] [stdout] 105 |     let x = &v[1..v.len()];
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]    --> src/main.rs:125:13
[INFO] [stdout]     |
[INFO] [stdout] 125 |     let mut v: Vec<Cell> = vec![Cell::Int(1), Cell::Text("宋诚中".to_string()), Cell::Float(20.0)];
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:128:13
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let mut x = String::new();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:129:13
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let mut x = "HelloWorld".to_string();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let x = a.to_string() + &b + &c;  // &String -> &str , &c -> &c[..] , c引用变为c切片
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:139:9
[INFO] [stdout]     |
[INFO] [stdout] 139 |     let x = format!("{}{}{}", a, b, c);
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:158:13
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let mut x: HashMap<String, i32> = HashMap::new();
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `value`
[INFO] [stdout]    --> src/main.rs:169:9
[INFO] [stdout]     |
[INFO] [stdout] 169 |     let value = score["Hello1"];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]    --> src/main.rs:190:17
[INFO] [stdout]     |
[INFO] [stdout] 190 |             let result = f.read_to_string(&mut content).unwrap_or(0);
[INFO] [stdout]     |                 ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:224:35
[INFO] [stdout]     |
[INFO] [stdout] 224 |     fn some_function2<T: Summary>(s1: &T, s2: &T) {}
[INFO] [stdout]     |                                   ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:224:43
[INFO] [stdout]     |
[INFO] [stdout] 224 |     fn some_function2<T: Summary>(s1: &T, s2: &T) {}
[INFO] [stdout]     |                                           ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:225:47
[INFO] [stdout]     |
[INFO] [stdout] 225 |     fn some_function3<T: Summary, W: Summary>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                               ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:225:55
[INFO] [stdout]     |
[INFO] [stdout] 225 |     fn some_function3<T: Summary, W: Summary>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                                       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]    --> src/main.rs:226:47
[INFO] [stdout]     |
[INFO] [stdout] 226 |     fn some_function4<T: Summary, W: Display>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                               ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:226:55
[INFO] [stdout]     |
[INFO] [stdout] 226 |     fn some_function4<T: Summary, W: Display>(s1: &T, s2: &W) {}
[INFO] [stdout]     |                                                       ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:227:23
[INFO] [stdout]     |
[INFO] [stdout] 227 |     fn some_function5(item: &(impl Summary + Display)) {}
[INFO] [stdout]     |                       ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/main.rs:228:45
[INFO] [stdout]     |
[INFO] [stdout] 228 |     fn some_function6<T: Summary + Display>(item: &T) {}
[INFO] [stdout]     |                                             ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:229:61
[INFO] [stdout]     |
[INFO] [stdout] 229 |     fn some_function7<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) {}
[INFO] [stdout]     |                                                             ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/main.rs:229:68
[INFO] [stdout]     |
[INFO] [stdout] 229 |     fn some_function7<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) {}
[INFO] [stdout]     |                                                                    ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/main.rs:230:29
[INFO] [stdout]     |
[INFO] [stdout] 230 |     fn some_function8<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                             ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/main.rs:230:36
[INFO] [stdout]     |
[INFO] [stdout] 230 |     fn some_function8<T, U>(t: &T, u: &U)
[INFO] [stdout]     |                                    ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |     let mut v: Vec<&str> = Vec::new();
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |     let mut v: Vec<&str> = Vec::new();
[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: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:125:9
[INFO] [stdout]     |
[INFO] [stdout] 125 |     let mut v: Vec<Cell> = vec![Cell::Int(1), Cell::Text("宋诚中".to_string()), Cell::Float(20.0)];
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:128:9
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let mut x = String::new();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:129:9
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let mut x = "HelloWorld".to_string();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let mut x: HashMap<String, i32> = HashMap::new();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:125:9
[INFO] [stdout]     |
[INFO] [stdout] 125 |     let mut v: Vec<Cell> = vec![Cell::Int(1), Cell::Text("宋诚中".to_string()), Cell::Float(20.0)];
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:128:9
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let mut x = String::new();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:129:9
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let mut x = "HelloWorld".to_string();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let mut x: HashMap<String, i32> = HashMap::new();
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `learn`
[INFO] [stdout]   --> src/main.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn learn() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `learn`
[INFO] [stdout]   --> src/main.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn learn() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 44 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.23s
[INFO] [stdout] warning: 44 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "68a1cac522e804fbfe3c3242688bf218a1647127eb1ece6cbf440bc0746c51ae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "68a1cac522e804fbfe3c3242688bf218a1647127eb1ece6cbf440bc0746c51ae", kill_on_drop: false }`
[INFO] [stdout] 68a1cac522e804fbfe3c3242688bf218a1647127eb1ece6cbf440bc0746c51ae