[INFO] fetching crate rust_demos 0.1.0...
[INFO] building rust_demos-0.1.0 against master#ad85bc524b1ad696e42061ad8338d382dffbdbe5 for pr-146237-1
[INFO] extracting crate rust_demos 0.1.0 into /workspace/builds/worker-4-tc1/source
[INFO] started tweaking crates.io crate rust_demos 0.1.0
[INFO] finished tweaking crates.io crate rust_demos 0.1.0
[INFO] tweaked toml for crates.io crate rust_demos 0.1.0 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate rust_demos 0.1.0 on toolchain ad85bc524b1ad696e42061ad8338d382dffbdbe5
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ad85bc524b1ad696e42061ad8338d382dffbdbe5" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate rust_demos 0.1.0 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" "+ad85bc524b1ad696e42061ad8338d382dffbdbe5" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+ad85bc524b1ad696e42061ad8338d382dffbdbe5" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f91bea050f376ab6b51869c8125f2aef31f6c5d09bf2fb02a0a6e491506208a3
[INFO] running `Command { std: "docker" "start" "-a" "f91bea050f376ab6b51869c8125f2aef31f6c5d09bf2fb02a0a6e491506208a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f91bea050f376ab6b51869c8125f2aef31f6c5d09bf2fb02a0a6e491506208a3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f91bea050f376ab6b51869c8125f2aef31f6c5d09bf2fb02a0a6e491506208a3", kill_on_drop: false }`
[INFO] [stdout] f91bea050f376ab6b51869c8125f2aef31f6c5d09bf2fb02a0a6e491506208a3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+ad85bc524b1ad696e42061ad8338d382dffbdbe5" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e0f8d861dfe0d8c15bd82eacc31cdf7da3f89bc254c1e640a1b875adc2757a3a
[INFO] running `Command { std: "docker" "start" "-a" "e0f8d861dfe0d8c15bd82eacc31cdf7da3f89bc254c1e640a1b875adc2757a3a", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v2.0.100
[INFO] [stderr]    Compiling smallvec v1.15.0
[INFO] [stderr]    Compiling signal-hook-registry v1.4.2
[INFO] [stderr]    Compiling serde v1.0.219
[INFO] [stderr]    Compiling parking_lot_core v0.9.10
[INFO] [stderr]    Compiling parking_lot v0.12.3
[INFO] [stderr]    Compiling serde_derive v1.0.219
[INFO] [stderr]    Compiling tokio-macros v2.5.0
[INFO] [stderr]    Compiling tokio v1.44.2
[INFO] [stderr]    Compiling serde_json v1.0.140
[INFO] [stderr]    Compiling rust_demos v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable `example` is assigned to, but never used
[INFO] [stdout]   --> src/bin/basics.rs:23:13
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut example;
[INFO] [stdout]    |             ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_example` instead
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: you might have meant to pattern match on the similarly named constant `INCR`
[INFO] [stdout]    |
[INFO] [stdout] 23 -     let mut example;
[INFO] [stdout] 23 +     let mut main::INCR;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `example` is never read
[INFO] [stdout]   --> src/bin/basics.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     example=10; 
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/basics.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut example;
[INFO] [stdout]    |         ----^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/bin/lifetime.rs:4:6
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let a:u8 = 25;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]  --> src/bin/lifetime.rs:5:6
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let p:&u8;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/bin/lifetime.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |         let b:u8 = 50;
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `must_use` that must be used
[INFO] [stdout]   --> src/bin/struct.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 |             format!{"Name is {} age is {} got {} marks",self.name,self.age,self.marks};
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 14 |             let _ = format!{"Name is {} age is {} got {} marks",self.name,self.age,self.marks};
[INFO] [stdout]    |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/sample.rs:46:19
[INFO] [stdout]    |
[INFO] [stdout] 46 | fn display_strlen(mut s:String)->(String,usize){
[INFO] [stdout]    |                   ----^
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/iterators.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut score_iter=scores.iter().clone();
[INFO] [stdout]   |         ----^^^^^^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `prime`
[INFO] [stdout]  --> src/bin/error.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let prime=match is_prime(n){
[INFO] [stdout]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_prime`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `get_username` is never used
[INFO] [stdout]   --> src/bin/slice_input.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn get_username(mail:&String)->&str{
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/unique.rs:6:6
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let mut word=input.trim().replace("\t","").replace(" ","");
[INFO] [stdout]   |         ----^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `error`
[INFO] [stdout]  --> src/bin/reading.rs:7:21
[INFO] [stdout]   |
[INFO] [stdout] 7 |                 unwrap_or_else(|error|{
[INFO] [stdout]   |                                 ^^^^^ help: if this is intentional, prefix it with an underscore: `_error`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `empid` is never read
[INFO] [stdout]  --> src/bin/empl_struct.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct Emp{
[INFO] [stdout]   |        --- field in this struct
[INFO] [stdout] 3 |     empid:i16,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `Emp` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 16.56s
[INFO] running `Command { std: "docker" "inspect" "e0f8d861dfe0d8c15bd82eacc31cdf7da3f89bc254c1e640a1b875adc2757a3a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e0f8d861dfe0d8c15bd82eacc31cdf7da3f89bc254c1e640a1b875adc2757a3a", kill_on_drop: false }`
[INFO] [stdout] e0f8d861dfe0d8c15bd82eacc31cdf7da3f89bc254c1e640a1b875adc2757a3a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+ad85bc524b1ad696e42061ad8338d382dffbdbe5" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 54092de94ccd5318573b8fad7f761b4e19d04851fbcc8f4d48db3ef9debf7e3c
[INFO] running `Command { std: "docker" "start" "-a" "54092de94ccd5318573b8fad7f761b4e19d04851fbcc8f4d48db3ef9debf7e3c", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust_demos v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function `get_username` is never used
[INFO] [stdout]   --> src/bin/slice_input.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn get_username(mail:&String)->&str{
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `empid` is never read
[INFO] [stdout]  --> src/bin/empl_struct.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct Emp{
[INFO] [stdout]   |        --- field in this struct
[INFO] [stdout] 3 |     empid:i16,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `Emp` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/bin/lifetime.rs:4:6
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let a:u8 = 25;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]  --> src/bin/lifetime.rs:5:6
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let p:&u8;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/bin/lifetime.rs:7:7
[INFO] [stdout]   |
[INFO] [stdout] 7 |         let b:u8 = 50;
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `must_use` that must be used
[INFO] [stdout]   --> src/bin/struct.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 |             format!{"Name is {} age is {} got {} marks",self.name,self.age,self.marks};
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 14 |             let _ = format!{"Name is {} age is {} got {} marks",self.name,self.age,self.marks};
[INFO] [stdout]    |             +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/unique.rs:6:6
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let mut word=input.trim().replace("\t","").replace(" ","");
[INFO] [stdout]   |         ----^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/bin/iterators.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let mut score_iter=scores.iter().clone();
[INFO] [stdout]   |         ----^^^^^^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `error`
[INFO] [stdout]  --> src/bin/reading.rs:7:21
[INFO] [stdout]   |
[INFO] [stdout] 7 |                 unwrap_or_else(|error|{
[INFO] [stdout]   |                                 ^^^^^ help: if this is intentional, prefix it with an underscore: `_error`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `example` is assigned to, but never used
[INFO] [stdout]   --> src/bin/basics.rs:23:13
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut example;
[INFO] [stdout]    |             ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_example` instead
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: you might have meant to pattern match on the similarly named constant `INCR`
[INFO] [stdout]    |
[INFO] [stdout] 23 -     let mut example;
[INFO] [stdout] 23 +     let mut main::INCR;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `example` is never read
[INFO] [stdout]   --> src/bin/basics.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     example=10; 
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/basics.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut example;
[INFO] [stdout]    |         ----^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `prime`
[INFO] [stdout]  --> src/bin/error.rs:3:6
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let prime=match is_prime(n){
[INFO] [stdout]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_prime`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/bin/sample.rs:46:19
[INFO] [stdout]    |
[INFO] [stdout] 46 | fn display_strlen(mut s:String)->(String,usize){
[INFO] [stdout]    |                   ----^
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 1.94s
[INFO] running `Command { std: "docker" "inspect" "54092de94ccd5318573b8fad7f761b4e19d04851fbcc8f4d48db3ef9debf7e3c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "54092de94ccd5318573b8fad7f761b4e19d04851fbcc8f4d48db3ef9debf7e3c", kill_on_drop: false }`
[INFO] [stdout] 54092de94ccd5318573b8fad7f761b4e19d04851fbcc8f4d48db3ef9debf7e3c