[INFO] cloning repository https://github.com/ukaushik-98/rust-playground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ukaushik-98/rust-playground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fukaushik-98%2Frust-playground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fukaushik-98%2Frust-playground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3540c1e27453c58e428bf91230d31269880c0a49
[INFO] checking ukaushik-98/rust-playground against try#54cf65b8d066c082e536455049b95943cf30378f for pr-151920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fukaushik-98%2Frust-playground" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/ukaushik-98/rust-playground
[INFO] finished tweaking git repo https://github.com/ukaushik-98/rust-playground
[INFO] tweaked toml for git repo https://github.com/ukaushik-98/rust-playground written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/ukaushik-98/rust-playground on toolchain 54cf65b8d066c082e536455049b95943cf30378f
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+54cf65b8d066c082e536455049b95943cf30378f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/ukaushik-98/rust-playground 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" "+54cf65b8d066c082e536455049b95943cf30378f" "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 unicode-ident v1.0.16
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+54cf65b8d066c082e536455049b95943cf30378f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a0ffbb5b4ec82a74014b9bbb526af0f7824f9df50f1c539f6f87aa7d0af81c30
[INFO] running `Command { std: "docker" "start" "-a" "a0ffbb5b4ec82a74014b9bbb526af0f7824f9df50f1c539f6f87aa7d0af81c30", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a0ffbb5b4ec82a74014b9bbb526af0f7824f9df50f1c539f6f87aa7d0af81c30", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a0ffbb5b4ec82a74014b9bbb526af0f7824f9df50f1c539f6f87aa7d0af81c30", kill_on_drop: false }`
[INFO] [stdout] a0ffbb5b4ec82a74014b9bbb526af0f7824f9df50f1c539f6f87aa7d0af81c30
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+54cf65b8d066c082e536455049b95943cf30378f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f1d1f7166d2b1b9c096239aed2c5739aef26a2889b5164b64ff58e296a5c421c
[INFO] running `Command { std: "docker" "start" "-a" "f1d1f7166d2b1b9c096239aed2c5739aef26a2889b5164b64ff58e296a5c421c", kill_on_drop: false }`
[INFO] [stderr]     Checking powerfmt v0.2.0
[INFO] [stderr]     Checking num-conv v0.1.0
[INFO] [stderr]     Checking time-core v0.1.2
[INFO] [stderr]     Checking deranged v0.3.11
[INFO] [stderr]     Checking time v0.3.37
[INFO] [stderr]     Checking rust-playground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/exercises/clock.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/exercises/gigasecond.rs:13:9
[INFO] [stdout]    |
[INFO] [stdout] 13 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Arc`, `Mutex`, `cell::Cell`, and `thread`
[INFO] [stdout]  --> src/hashmap/mod.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     cell::Cell,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 5 |     sync::{Arc, Mutex},
[INFO] [stdout]   |            ^^^  ^^^^^
[INFO] [stdout] 6 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/hashmap/mod.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `sync::Arc` and `thread`
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_cell2.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     sync::Arc,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 5 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `thread`
[INFO] [stdout]  --> src/mutex/mod.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Mutex` and `cell::Cell`
[INFO] [stdout]  --> src/send_sync/send.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     cell::Cell,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout] 3 |     sync::{Arc, Mutex},
[INFO] [stdout]   |                 ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rc::Rc`
[INFO] [stdout]  --> src/send_sync/sync.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     rc::Rc,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/static_lf/mod.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     /// foo(&x); // ❌ this is invalid since x is the T for the &T and does not live long enough
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 13 |     let y: &'static str = "hello";
[INFO] [stdout]    |     ------------------------------ rustdoc does not generate documentation for statements
[INFO] [stdout]    |
[INFO] [stdout]    = help: use `//` for a plain comment
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Arc`, `Mutex`, `cell::Cell`, and `thread`
[INFO] [stdout]  --> src/hashmap/mod.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     cell::Cell,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 5 |     sync::{Arc, Mutex},
[INFO] [stdout]   |            ^^^  ^^^^^
[INFO] [stdout] 6 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `sync::Arc` and `thread`
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_cell2.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     sync::Arc,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 5 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `thread`
[INFO] [stdout]  --> src/mutex/mod.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     thread,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Mutex` and `cell::Cell`
[INFO] [stdout]  --> src/send_sync/send.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     cell::Cell,
[INFO] [stdout]   |     ^^^^^^^^^^
[INFO] [stdout] 3 |     sync::{Arc, Mutex},
[INFO] [stdout]   |                 ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rc::Rc`
[INFO] [stdout]  --> src/send_sync/sync.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     rc::Rc,
[INFO] [stdout]   |     ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/static_lf/mod.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     /// foo(&x); // ❌ this is invalid since x is the T for the &T and does not live long enough
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 13 |     let y: &'static str = "hello";
[INFO] [stdout]    |     ------------------------------ rustdoc does not generate documentation for statements
[INFO] [stdout]    |
[INFO] [stdout]    = help: use `//` for a plain comment
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]  --> src/interior_mutability/rc.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let y = Arc::clone(&x);
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/interior_mutability/rc.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let y = Arc::clone(&x);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/interior_mutability/mod.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let mut x = 5;
[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/interior_mutability/mod.rs:53:9
[INFO] [stdout]    |
[INFO] [stdout] 53 |     let mut y = Cell::new(x);
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/interior_mutability/mod.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let z = y.get();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/interior_mutability/mod.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let z = Cell::new(y);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/interior_mutability/mod.rs:89:9
[INFO] [stdout]    |
[INFO] [stdout] 89 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:98:9
[INFO] [stdout]    |
[INFO] [stdout] 98 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:109:9
[INFO] [stdout]     |
[INFO] [stdout] 109 |     let mut z = Cell::new(&mut x);
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:108:9
[INFO] [stdout]     |
[INFO] [stdout] 108 |     let y = &mut x;
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/interior_mutability/mod.rs:131:9
[INFO] [stdout]     |
[INFO] [stdout] 131 |     let mut x = String::from("");
[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/interior_mutability/mod.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut x = Dumb { inner: "" };
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:147:9
[INFO] [stdout]     |
[INFO] [stdout] 147 |     let y = &x;
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let y = x.borrow();
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/self_box/mod.rs:13:9
[INFO] [stdout]    |
[INFO] [stdout] 13 |     let mut v = vec!["hello"];
[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/self_box/mod.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let mut x = Box::new(&v);
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/send_sync/send.rs:17:22
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn foo_sync<T: Sync>(a: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/send_sync/send.rs:19:22
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn foo_send<T: Send>(a: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/send_sync/sync.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let y: &mut Vec<i32> = &mut x;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/send_sync/sync.rs:66:9
[INFO] [stdout]    |
[INFO] [stdout] 66 |     let mut x = vec![1, 2, 3];
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `z` is assigned to, but never used
[INFO] [stdout]   --> src/send_sync/sync.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let mut z = &x;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_z` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `z` is never read
[INFO] [stdout]   --> src/send_sync/sync.rs:75:5
[INFO] [stdout]    |
[INFO] [stdout] 75 |     z = &y;
[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: unused variable: `y`
[INFO] [stdout]   --> src/send_sync/sync.rs:96:13
[INFO] [stdout]    |
[INFO] [stdout] 96 |         let y = arc_mx_clone.lock();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:101:25
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn foo5<T: Send + Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:103:18
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn foo6<T: Send>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                  ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:105:18
[INFO] [stdout]     |
[INFO] [stdout] 105 | fn foo7<T: Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                  ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/send_sync/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let a = d;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/send_sync/mod.rs:16:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     let c: Cell<&Vec<i32>> = Cell::new(d);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/send_sync/mod.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let b = y;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/send_sync/mod.rs:25:22
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn foo_sync<T: Sync>(x: T) {}
[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/send_sync/mod.rs:27:22
[INFO] [stdout]    |
[INFO] [stdout] 27 | fn foo_send<T: Send>(x: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/send_sync/mod.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let mut x = vec![42];
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]  --> src/static_lf/mod.rs:7:20
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn foo<T: 'static>(x: T) {}
[INFO] [stdout]   |                    ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/variance/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let mut world: Box<&'b str>;
[INFO] [stdout]   |         ----^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `world` is assigned to, but never used
[INFO] [stdout]  --> src/variance/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let mut world: Box<&'b str>;
[INFO] [stdout]   |         ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_world` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `world` is never read
[INFO] [stdout]  --> src/variance/mod.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     world = hello;
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `garbagio` is never read
[INFO] [stdout]   --> src/variance/mod.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |         garbagio = "new garbagio";
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `base` is never used
[INFO] [stdout]  --> src/aliasing/mod.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn base<'a>(x: &'a i32, y: &'a mut i32) -> &'a mut i32 {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `base_opt` is never used
[INFO] [stdout]   --> src/aliasing/mod.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn base_opt<'a>(x: &'a i32, y: &'a mut i32) -> &'a mut i32 {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `alias` is never used
[INFO] [stdout]   --> src/aliasing/mod.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn alias() {}
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `datetime` is never used
[INFO] [stdout]   --> src/exercises/gigasecond.rs:62:8
[INFO] [stdout]    |
[INFO] [stdout] 62 |     fn datetime(
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]   --> src/hashmap/mod.rs:11:4
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn foo(keys: Vec<&str>, data: Vec<Vec<i32>>) /* ->  HashMap<String, &Vec<i32>> */
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/hashmap/mod.rs:26:4
[INFO] [stdout]    |
[INFO] [stdout] 26 | fn foo2<'a>(keys: &'a Vec<&str>, data: &'a Vec<Vec<i32>>) -> HashMap<&'a str, &'a Vec<i32>> {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/hashmap/mod.rs:34:4
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn foo3(keys: Vec<&str>, data: Vec<Vec<i32>>) -> HashMap<String, Vec<i32>> {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/interior_mutability/mod.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn foo() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:18:4
[INFO] [stdout]    |
[INFO] [stdout] 18 | fn foo2() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:28:4
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn foo3() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:38:4
[INFO] [stdout]    |
[INFO] [stdout] 38 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo5` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn foo5(_x: &mut Vec<i32>) {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo6` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:58:4
[INFO] [stdout]    |
[INFO] [stdout] 58 | fn foo6() -> Vec<i32> {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:66:4
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn bar(mut a: Cell<&mut Vec<i32>>) {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo7` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn foo7() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo8` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:79:4
[INFO] [stdout]    |
[INFO] [stdout] 79 | fn foo8() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo9` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:88:4
[INFO] [stdout]    |
[INFO] [stdout] 88 | fn foo9() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo10` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:97:4
[INFO] [stdout]    |
[INFO] [stdout] 97 | fn foo10() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo11` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:106:4
[INFO] [stdout]     |
[INFO] [stdout] 106 | fn foo11() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo12` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn foo12() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Dumb` is never constructed
[INFO] [stdout]    --> src/interior_mutability/mod.rs:126:8
[INFO] [stdout]     |
[INFO] [stdout] 126 | struct Dumb<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbo` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:130:4
[INFO] [stdout]     |
[INFO] [stdout] 130 | fn garbo<'a>() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbo2` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:137:4
[INFO] [stdout]     |
[INFO] [stdout] 137 | fn garbo2<'a>() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar2` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn bar2() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar3` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:151:4
[INFO] [stdout]     |
[INFO] [stdout] 151 | fn bar3() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GCell2` is never constructed
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_cell2.rs:8:12
[INFO] [stdout]   |
[INFO] [stdout] 8 | pub struct GCell2<T> {
[INFO] [stdout]   |            ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `set`, `get`, and `bad_get` are never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_cell2.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl<T> GCell2<T> {
[INFO] [stdout]    | ----------------- associated items in this implementation
[INFO] [stdout] 13 |     pub fn new(value: T) -> GCell2<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 19 |     pub fn set(&self, value: T) {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 23 |     pub fn get(&self) -> T
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 30 |     fn bad_get(&self) -> &T {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `full` is never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_cell2.rs:41:4
[INFO] [stdout]    |
[INFO] [stdout] 41 | fn full() -> Vec<&'static str> {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `full2` is never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_cell2.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn full2(z: Rc<Cell<Vec<&str>>>) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRef2` is never constructed
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref2.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GRef2<'g2, T> {
[INFO] [stdout]   |            ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref2.rs:9:12
[INFO] [stdout]   |
[INFO] [stdout] 8 | impl<'g2, T> GRef2<'g2, T> {
[INFO] [stdout]   | -------------------------- associated function in this implementation
[INFO] [stdout] 9 |     pub fn new(refcell: &'g2 GRefCell2<T>) -> Self {
[INFO] [stdout]   |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `GRefCell2State` is never used
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref_cell2.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub enum GRefCell2State {
[INFO] [stdout]   |          ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRefCell2` is never constructed
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:12:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub struct GRefCell2<T> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `borrow`, and `borrow_mut` are never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:18:12
[INFO] [stdout]    |
[INFO] [stdout] 17 | impl<T> GRefCell2<T> {
[INFO] [stdout]    | -------------------- associated items in this implementation
[INFO] [stdout] 18 |     pub fn new(value: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<T>> {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 39 |     pub fn borrow_mut(&self) -> Option<&mut T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRefMut2` is never constructed
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref_mut2.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GRefMut2<'g2, T> {
[INFO] [stdout]   |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_mut2.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'g2, T> GRefMut2<'g2, T> {
[INFO] [stdout]    | ----------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'g2 GRefCell2<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageCell` is never constructed
[INFO] [stdout]  --> src/interior_mutability/garbage_cell.rs:3:12
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub struct GarbageCell<T> {
[INFO] [stdout]   |            ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `set`, `get`, and `bad_get` are never used
[INFO] [stdout]   --> src/interior_mutability/garbage_cell.rs:8:12
[INFO] [stdout]    |
[INFO] [stdout]  7 | impl<T> GarbageCell<T> {
[INFO] [stdout]    | ---------------------- associated items in this implementation
[INFO] [stdout]  8 |     pub fn new(value: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 14 |     pub fn set(&self, value: T) {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 18 |     pub fn get(&self) -> T
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 25 |     fn bad_get(&self) -> &T {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRef` is never constructed
[INFO] [stdout]  --> src/interior_mutability/garbage_ref.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'garbage_ref_cell, T> GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]    | ----------------------------------------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'garbage_ref_cell GarbageRefCell<T>) -> GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `RefCellState` is never used
[INFO] [stdout]  --> src/interior_mutability/garbage_ref_cell.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub enum RefCellState {
[INFO] [stdout]   |          ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefCell` is never constructed
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:12:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub struct GarbageRefCell<T> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefMut` is never constructed
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:17:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `borrow`, and `borrow_mut` are never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:22:12
[INFO] [stdout]    |
[INFO] [stdout] 21 | impl<T> GarbageRefCell<T> {
[INFO] [stdout]    | ------------------------- associated items in this implementation
[INFO] [stdout] 22 |     pub fn new(value: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<T>> {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     pub fn borrow_mut(&self) -> Option<&mut T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefMut` is never constructed
[INFO] [stdout]  --> src/interior_mutability/garbage_ref_mut.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]   |            ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_mut.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'garbage_ref_cell, T> GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]    | -------------------------------------------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'garbage_ref_cell GarbageRefCell<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/interior_mutability/rc.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn foo() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]  --> src/interior_mutability/rc.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn foo2() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbage` is never used
[INFO] [stdout]   --> src/mutex/mod.rs:76:4
[INFO] [stdout]    |
[INFO] [stdout] 76 | fn garbage<'a>(hello: &'a String) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `box_vec` is never used
[INFO] [stdout]  --> src/self_box/mod.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn box_vec(x: &mut Vec<&str>) {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `boxing` is never used
[INFO] [stdout]  --> src/self_box/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn boxing() {
[INFO] [stdout]   |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `boxing2` is never used
[INFO] [stdout]   --> src/self_box/mod.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn boxing2() {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/send_sync/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn foo<'a>(x: &'a Vec<i32>) -> Cell<&'a Vec<i32>> {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn foo2<'a>() /*  -> Cell<&Vec<i32>> */
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn bar() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_sync` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn foo_sync<T: Sync>(x: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_send` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:27:4
[INFO] [stdout]    |
[INFO] [stdout] 27 | fn foo_send<T: Send>(x: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:29:4
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn foo3() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:34:4
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `dumb` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:39:4
[INFO] [stdout]    |
[INFO] [stdout] 39 | fn dumb() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_sync` is never used
[INFO] [stdout]   --> src/send_sync/send.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn foo_sync<T: Sync>(a: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_send` is never used
[INFO] [stdout]   --> src/send_sync/send.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn foo_send<T: Send>(a: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_mut` is never used
[INFO] [stdout]   --> src/send_sync/send.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn foo_mut(a: &mut &mut Vec<&str>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/send_sync/send.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn foo2() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]  --> src/send_sync/sync.rs:8:4
[INFO] [stdout]   |
[INFO] [stdout] 8 | fn foo2<'a: 'static>(x: Arc<&'a Vec<i32>>) {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn foo() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `runner` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:33:4
[INFO] [stdout]    |
[INFO] [stdout] 33 | fn runner() {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:58:4
[INFO] [stdout]    |
[INFO] [stdout] 58 | fn bar<T>(x: T)
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar2` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn bar2() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn foo3<'a, 'b, T>(x: &'a Vec<&'a str>, y: &'b Vec<&'b str>)
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:81:4
[INFO] [stdout]    |
[INFO] [stdout] 81 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo5` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn foo5<T: Send + Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo6` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn foo6<T: Send>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo7` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:105:4
[INFO] [stdout]     |
[INFO] [stdout] 105 | fn foo7<T: Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo8` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:107:4
[INFO] [stdout]     |
[INFO] [stdout] 107 | fn foo8() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/static_lf/mod.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn foo<T: 'static>(x: T) {}
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]  --> src/static_lf/mod.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn bar() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `until_char` is never used
[INFO] [stdout]   --> src/str_split/mod.rs:71:4
[INFO] [stdout]    |
[INFO] [stdout] 71 | fn until_char<'a, 'b>(s: &'a str, c: &'b str) -> &'a str {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `new_tester` is never used
[INFO] [stdout]  --> src/variance/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn new_tester<'b>() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:25:19
[INFO] [stdout]    |
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<T>> {
[INFO] [stdout]    |                   ^^^^^            ^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<'_, T>> {
[INFO] [stdout]    |                                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:29:19
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<T>> {
[INFO] [stdout]    |                   ^^^^^            ^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<'_, T>> {
[INFO] [stdout]    |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_cell2.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 |     let y = x.bad_get();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[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/interior_mutability/g2/garbage_cell2.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let mut x = vec!["hello"];
[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: `y`
[INFO] [stdout]  --> src/interior_mutability/rc.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let y = Arc::clone(&x);
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/interior_mutability/rc.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let y = Arc::clone(&x);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/interior_mutability/mod.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let mut x = 5;
[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/interior_mutability/mod.rs:53:9
[INFO] [stdout]    |
[INFO] [stdout] 53 |     let mut y = Cell::new(x);
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/interior_mutability/mod.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let z = y.get();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/interior_mutability/mod.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let z = Cell::new(y);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/interior_mutability/mod.rs:89:9
[INFO] [stdout]    |
[INFO] [stdout] 89 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:98:9
[INFO] [stdout]    |
[INFO] [stdout] 98 |     let mut x = vec![1, 2, 3];
[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/interior_mutability/mod.rs:109:9
[INFO] [stdout]     |
[INFO] [stdout] 109 |     let mut z = Cell::new(&mut x);
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:108:9
[INFO] [stdout]     |
[INFO] [stdout] 108 |     let y = &mut x;
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/interior_mutability/mod.rs:131:9
[INFO] [stdout]     |
[INFO] [stdout] 131 |     let mut x = String::from("");
[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/interior_mutability/mod.rs:138:9
[INFO] [stdout]     |
[INFO] [stdout] 138 |     let mut x = Dumb { inner: "" };
[INFO] [stdout]     |         ----^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:147:9
[INFO] [stdout]     |
[INFO] [stdout] 147 |     let y = &x;
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/interior_mutability/mod.rs:158:9
[INFO] [stdout]     |
[INFO] [stdout] 158 |     let y = x.borrow();
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/self_box/mod.rs:13:9
[INFO] [stdout]    |
[INFO] [stdout] 13 |     let mut v = vec!["hello"];
[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/self_box/mod.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let mut x = Box::new(&v);
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/send_sync/send.rs:17:22
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn foo_sync<T: Sync>(a: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/send_sync/send.rs:19:22
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn foo_send<T: Send>(a: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/send_sync/sync.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let y: &mut Vec<i32> = &mut x;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/send_sync/sync.rs:66:9
[INFO] [stdout]    |
[INFO] [stdout] 66 |     let mut x = vec![1, 2, 3];
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `z` is assigned to, but never used
[INFO] [stdout]   --> src/send_sync/sync.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let mut z = &x;
[INFO] [stdout]    |         ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_z` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `z` is never read
[INFO] [stdout]   --> src/send_sync/sync.rs:75:5
[INFO] [stdout]    |
[INFO] [stdout] 75 |     z = &y;
[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: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let x = Mutex::new(10);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `arc_fn` is never used
[INFO] [stdout]  --> src/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn arc_fn<'a, T>(test: Arc<&'a MutexGuard<T>>) {
[INFO] [stdout]   |    ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     drop(*test);
[INFO] [stdout]   |     ^^^^^-----^
[INFO] [stdout]   |          |
[INFO] [stdout]   |          argument has type `&std::sync::MutexGuard<'_, T>`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dropping_references)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the expression or result
[INFO] [stdout]   |
[INFO] [stdout] 7 -     drop(*test);
[INFO] [stdout] 7 +     let _ = *test;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |     let x = Mutex::new(10);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `arc_fn` is never used
[INFO] [stdout]  --> src/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn arc_fn<'a, T>(test: Arc<&'a MutexGuard<T>>) {
[INFO] [stdout]   |    ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: calls to `std::mem::drop` with a reference instead of an owned value does nothing
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 |     drop(*test);
[INFO] [stdout]   |     ^^^^^-----^
[INFO] [stdout]   |          |
[INFO] [stdout]   |          argument has type `&std::sync::MutexGuard<'_, T>`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dropping_references)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the expression or result
[INFO] [stdout]   |
[INFO] [stdout] 7 -     drop(*test);
[INFO] [stdout] 7 +     let _ = *test;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/send_sync/sync.rs:96:13
[INFO] [stdout]    |
[INFO] [stdout] 96 |         let y = arc_mx_clone.lock();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:101:25
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn foo5<T: Send + Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:103:18
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn foo6<T: Send>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                  ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/send_sync/sync.rs:105:18
[INFO] [stdout]     |
[INFO] [stdout] 105 | fn foo7<T: Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |                  ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/send_sync/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let a = d;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/send_sync/mod.rs:16:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     let c: Cell<&Vec<i32>> = Cell::new(d);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/send_sync/mod.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let b = y;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/send_sync/mod.rs:25:22
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn foo_sync<T: Sync>(x: T) {}
[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/send_sync/mod.rs:27:22
[INFO] [stdout]    |
[INFO] [stdout] 27 | fn foo_send<T: Send>(x: T) {}
[INFO] [stdout]    |                      ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/send_sync/mod.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let mut x = vec![42];
[INFO] [stdout]    |         ----^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]  --> src/static_lf/mod.rs:7:20
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn foo<T: 'static>(x: T) {}
[INFO] [stdout]   |                    ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/variance/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let mut world: Box<&'b str>;
[INFO] [stdout]   |         ----^^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `world` is assigned to, but never used
[INFO] [stdout]  --> src/variance/mod.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let mut world: Box<&'b str>;
[INFO] [stdout]   |         ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_world` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `world` is never read
[INFO] [stdout]  --> src/variance/mod.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 |     world = hello;
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `garbagio` is never read
[INFO] [stdout]   --> src/variance/mod.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |         garbagio = "new garbagio";
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `base` is never used
[INFO] [stdout]  --> src/aliasing/mod.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn base<'a>(x: &'a i32, y: &'a mut i32) -> &'a mut i32 {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `alias` is never used
[INFO] [stdout]   --> src/aliasing/mod.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn alias() {}
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/interior_mutability/mod.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn foo() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:18:4
[INFO] [stdout]    |
[INFO] [stdout] 18 | fn foo2() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:28:4
[INFO] [stdout]    |
[INFO] [stdout] 28 | fn foo3() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:38:4
[INFO] [stdout]    |
[INFO] [stdout] 38 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo5` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:51:4
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn foo5(_x: &mut Vec<i32>) {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo7` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn foo7() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo8` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:79:4
[INFO] [stdout]    |
[INFO] [stdout] 79 | fn foo8() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo9` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:88:4
[INFO] [stdout]    |
[INFO] [stdout] 88 | fn foo9() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo10` is never used
[INFO] [stdout]   --> src/interior_mutability/mod.rs:97:4
[INFO] [stdout]    |
[INFO] [stdout] 97 | fn foo10() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo11` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:106:4
[INFO] [stdout]     |
[INFO] [stdout] 106 | fn foo11() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo12` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn foo12() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Dumb` is never constructed
[INFO] [stdout]    --> src/interior_mutability/mod.rs:126:8
[INFO] [stdout]     |
[INFO] [stdout] 126 | struct Dumb<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbo` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:130:4
[INFO] [stdout]     |
[INFO] [stdout] 130 | fn garbo<'a>() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbo2` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:137:4
[INFO] [stdout]     |
[INFO] [stdout] 137 | fn garbo2<'a>() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar2` is never used
[INFO] [stdout]    --> src/interior_mutability/mod.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn bar2() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `get` is never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_cell2.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl<T> GCell2<T> {
[INFO] [stdout]    | ----------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 23 |     pub fn get(&self) -> T
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRef2` is never constructed
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref2.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GRef2<'g2, T> {
[INFO] [stdout]   |            ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref2.rs:9:12
[INFO] [stdout]   |
[INFO] [stdout] 8 | impl<'g2, T> GRef2<'g2, T> {
[INFO] [stdout]   | -------------------------- associated function in this implementation
[INFO] [stdout] 9 |     pub fn new(refcell: &'g2 GRefCell2<T>) -> Self {
[INFO] [stdout]   |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `GRefCell2State` is never used
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref_cell2.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub enum GRefCell2State {
[INFO] [stdout]   |          ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRefCell2` is never constructed
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:12:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub struct GRefCell2<T> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `borrow`, and `borrow_mut` are never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:18:12
[INFO] [stdout]    |
[INFO] [stdout] 17 | impl<T> GRefCell2<T> {
[INFO] [stdout]    | -------------------- associated items in this implementation
[INFO] [stdout] 18 |     pub fn new(value: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<T>> {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 39 |     pub fn borrow_mut(&self) -> Option<&mut T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GRefMut2` is never constructed
[INFO] [stdout]  --> src/interior_mutability/g2/garbage_ref_mut2.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GRefMut2<'g2, T> {
[INFO] [stdout]   |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_mut2.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'g2, T> GRefMut2<'g2, T> {
[INFO] [stdout]    | ----------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'g2 GRefCell2<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `get` is never used
[INFO] [stdout]   --> src/interior_mutability/garbage_cell.rs:18:12
[INFO] [stdout]    |
[INFO] [stdout]  7 | impl<T> GarbageCell<T> {
[INFO] [stdout]    | ---------------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 18 |     pub fn get(&self) -> T
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRef` is never constructed
[INFO] [stdout]  --> src/interior_mutability/garbage_ref.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'garbage_ref_cell, T> GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]    | ----------------------------------------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'garbage_ref_cell GarbageRefCell<T>) -> GarbageRef<'garbage_ref_cell, T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `RefCellState` is never used
[INFO] [stdout]  --> src/interior_mutability/garbage_ref_cell.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub enum RefCellState {
[INFO] [stdout]   |          ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefCell` is never constructed
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:12:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | pub struct GarbageRefCell<T> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefMut` is never constructed
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:17:8
[INFO] [stdout]    |
[INFO] [stdout] 17 | struct GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `borrow`, and `borrow_mut` are never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:22:12
[INFO] [stdout]    |
[INFO] [stdout] 21 | impl<T> GarbageRefCell<T> {
[INFO] [stdout]    | ------------------------- associated items in this implementation
[INFO] [stdout] 22 |     pub fn new(value: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<T>> {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     pub fn borrow_mut(&self) -> Option<&mut T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `GarbageRefMut` is never constructed
[INFO] [stdout]  --> src/interior_mutability/garbage_ref_mut.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | pub struct GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]   |            ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_mut.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'garbage_ref_cell, T> GarbageRefMut<'garbage_ref_cell, T> {
[INFO] [stdout]    | -------------------------------------------------------------- associated function in this implementation
[INFO] [stdout] 10 |     pub fn new(refcell: &'garbage_ref_cell GarbageRefCell<T>) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/interior_mutability/rc.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn foo() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]  --> src/interior_mutability/rc.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn foo2() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `garbage` is never used
[INFO] [stdout]   --> src/mutex/mod.rs:76:4
[INFO] [stdout]    |
[INFO] [stdout] 76 | fn garbage<'a>(hello: &'a String) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `box_vec` is never used
[INFO] [stdout]  --> src/self_box/mod.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn box_vec(x: &mut Vec<&str>) {
[INFO] [stdout]   |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `boxing` is never used
[INFO] [stdout]  --> src/self_box/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn boxing() {
[INFO] [stdout]   |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `boxing2` is never used
[INFO] [stdout]   --> src/self_box/mod.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn boxing2() {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/send_sync/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn foo<'a>(x: &'a Vec<i32>) -> Cell<&'a Vec<i32>> {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:12:4
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn foo2<'a>() /*  -> Cell<&Vec<i32>> */
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn bar() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_sync` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn foo_sync<T: Sync>(x: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_send` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:27:4
[INFO] [stdout]    |
[INFO] [stdout] 27 | fn foo_send<T: Send>(x: T) {}
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:29:4
[INFO] [stdout]    |
[INFO] [stdout] 29 | fn foo3() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:34:4
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `dumb` is never used
[INFO] [stdout]   --> src/send_sync/mod.rs:39:4
[INFO] [stdout]    |
[INFO] [stdout] 39 | fn dumb() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo_mut` is never used
[INFO] [stdout]   --> src/send_sync/send.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn foo_mut(a: &mut &mut Vec<&str>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo2` is never used
[INFO] [stdout]  --> src/send_sync/sync.rs:8:4
[INFO] [stdout]   |
[INFO] [stdout] 8 | fn foo2<'a: 'static>(x: Arc<&'a Vec<i32>>) {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:19:4
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn foo() {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `runner` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:33:4
[INFO] [stdout]    |
[INFO] [stdout] 33 | fn runner() {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:58:4
[INFO] [stdout]    |
[INFO] [stdout] 58 | fn bar<T>(x: T)
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar2` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:65:4
[INFO] [stdout]    |
[INFO] [stdout] 65 | fn bar2() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo3` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:70:4
[INFO] [stdout]    |
[INFO] [stdout] 70 | fn foo3<'a, 'b, T>(x: &'a Vec<&'a str>, y: &'b Vec<&'b str>)
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo4` is never used
[INFO] [stdout]   --> src/send_sync/sync.rs:81:4
[INFO] [stdout]    |
[INFO] [stdout] 81 | fn foo4() {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo5` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn foo5<T: Send + Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo6` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:103:4
[INFO] [stdout]     |
[INFO] [stdout] 103 | fn foo6<T: Send>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo7` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:105:4
[INFO] [stdout]     |
[INFO] [stdout] 105 | fn foo7<T: Sync>(a: Arc<Mutex<T>>) {}
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo8` is never used
[INFO] [stdout]    --> src/send_sync/sync.rs:107:4
[INFO] [stdout]     |
[INFO] [stdout] 107 | fn foo8() {
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `foo` is never used
[INFO] [stdout]  --> src/static_lf/mod.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn foo<T: 'static>(x: T) {}
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bar` is never used
[INFO] [stdout]  --> src/static_lf/mod.rs:9:4
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn bar() {
[INFO] [stdout]   |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `new_tester` is never used
[INFO] [stdout]  --> src/variance/mod.rs:5:4
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn new_tester<'b>() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/interior_mutability/g2/garbage_ref_cell2.rs:25:19
[INFO] [stdout]    |
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<T>> {
[INFO] [stdout]    |                   ^^^^^            ^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 25 |     pub fn borrow(&self) -> Option<GRef2<'_, T>> {
[INFO] [stdout]    |                                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/interior_mutability/garbage_ref_cell.rs:29:19
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<T>> {
[INFO] [stdout]    |                   ^^^^^            ^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                   |
[INFO] [stdout]    |                   the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn borrow(&self) -> Option<GarbageRef<'_, T>> {
[INFO] [stdout]    |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.12s
[INFO] running `Command { std: "docker" "inspect" "f1d1f7166d2b1b9c096239aed2c5739aef26a2889b5164b64ff58e296a5c421c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f1d1f7166d2b1b9c096239aed2c5739aef26a2889b5164b64ff58e296a5c421c", kill_on_drop: false }`
[INFO] [stdout] f1d1f7166d2b1b9c096239aed2c5739aef26a2889b5164b64ff58e296a5c421c
