[INFO] cloning repository https://github.com/mikeleppane/Crust-of-Rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/mikeleppane/Crust-of-Rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmikeleppane%2FCrust-of-Rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmikeleppane%2FCrust-of-Rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b4e5a00ce068794a2fef0b86a454ab48e44f4764
[INFO] checking mikeleppane/Crust-of-Rust against master#1f12b9b0fdbe735968ac002792a720f0ba4faca6 for crater-rollup-uwu
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmikeleppane%2FCrust-of-Rust" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mikeleppane/Crust-of-Rust on toolchain 1f12b9b0fdbe735968ac002792a720f0ba4faca6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/mikeleppane/Crust-of-Rust
[INFO] finished tweaking git repo https://github.com/mikeleppane/Crust-of-Rust
[INFO] tweaked toml for git repo https://github.com/mikeleppane/Crust-of-Rust written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/mikeleppane/Crust-of-Rust 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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] dcddc6d8a3d9ffdc79f0d80f76bebcd6f1ee12322d32aadf12f21bf60ee6c2b8
[INFO] running `Command { std: "docker" "start" "-a" "dcddc6d8a3d9ffdc79f0d80f76bebcd6f1ee12322d32aadf12f21bf60ee6c2b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dcddc6d8a3d9ffdc79f0d80f76bebcd6f1ee12322d32aadf12f21bf60ee6c2b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dcddc6d8a3d9ffdc79f0d80f76bebcd6f1ee12322d32aadf12f21bf60ee6c2b8", kill_on_drop: false }`
[INFO] [stdout] dcddc6d8a3d9ffdc79f0d80f76bebcd6f1ee12322d32aadf12f21bf60ee6c2b8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8d7e3a1e58a67e82fd3f90df6923f2c103709e04f6b9e89b56eed7d92d90af41
[INFO] running `Command { std: "docker" "start" "-a" "8d7e3a1e58a67e82fd3f90df6923f2c103709e04f6b9e89b56eed7d92d90af41", kill_on_drop: false }`
[INFO] [stderr]     Checking diff v0.1.13
[INFO] [stderr]     Checking yansi v0.5.1
[INFO] [stderr]     Checking pretty_assertions v1.3.0
[INFO] [stderr]     Checking crust-of-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `pretty_assertions::assert_eq`
[INFO] [stdout]   --> src/drop_check/boks.rs:41:9
[INFO] [stdout]    |
[INFO] [stdout] 41 |     use pretty_assertions::assert_eq;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `LOCKED` is never used
[INFO] [stdout]  --> src/atomics_and_memory_ordering/atomics.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | const LOCKED: bool = true;
[INFO] [stdout]   |       ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `UNLOCKED` is never used
[INFO] [stdout]  --> src/atomics_and_memory_ordering/atomics.rs:5:7
[INFO] [stdout]   |
[INFO] [stdout] 5 | const UNLOCKED: bool = false;
[INFO] [stdout]   |       ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyMutex` is never constructed
[INFO] [stdout]  --> src/atomics_and_memory_ordering/atomics.rs:7:12
[INFO] [stdout]   |
[INFO] [stdout] 7 | pub struct MyMutex<T> {
[INFO] [stdout]   |            ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `with_lock` are never used
[INFO] [stdout]   --> src/atomics_and_memory_ordering/atomics.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 14 | impl<T> MyMutex<T> {
[INFO] [stdout]    | ------------------ associated items in this implementation
[INFO] [stdout] 15 |     pub fn new(t: T) -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 22 |     fn with_lock<R>(&self, f: impl FnOnce(&mut T) -> R) -> R {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `send` is never used
[INFO] [stdout]   --> src/channels/panama.rs:33:12
[INFO] [stdout]    |
[INFO] [stdout] 32 | impl<T> Sender<T> {
[INFO] [stdout]    | ----------------- method in this implementation
[INFO] [stdout] 33 |     pub fn send(&mut self, t: T) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `channel` is never used
[INFO] [stdout]   --> src/channels/panama.rs:87:8
[INFO] [stdout]    |
[INFO] [stdout] 87 | pub fn channel<T>() -> (Sender<T>, Receiver<T>) {
[INFO] [stdout]    |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `hei` and `not_ok` are never used
[INFO] [stdout]  --> src/dispatch_and_fat_pointers/main.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait Hei {
[INFO] [stdout]   |           --- associated items in this trait
[INFO] [stdout] 2 |     fn hei(&self);
[INFO] [stdout]   |        ^^^
[INFO] [stdout] 3 |
[INFO] [stdout] 4 |     fn not_ok()
[INFO] [stdout]   |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strlen` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:31:4
[INFO] [stdout]    |
[INFO] [stdout] 31 | fn strlen(s: impl AsRef<str>) -> usize {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strlen_dyn` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:35:4
[INFO] [stdout]    |
[INFO] [stdout] 35 | fn strlen_dyn(s: Box<dyn AsRef<str>>) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bool_then` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:39:8
[INFO] [stdout]    |
[INFO] [stdout] 39 | pub fn bool_then<T>(b: bool, f: impl FnOnce() -> T) -> Option<T> {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `HeiAsRef` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:47:11
[INFO] [stdout]    |
[INFO] [stdout] 47 | pub trait HeiAsRef: Hei + AsRef<str> {}
[INFO] [stdout]    |           ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `baz` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:49:8
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn baz(s: &dyn HeiAsRef) {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `slice_of_trait_object` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:55:8
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub fn slice_of_trait_object(v: &[&dyn AsRef<str>]) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `main` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:61:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | pub fn main() {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `ny` is never used
[INFO] [stdout]   --> src/drop_check/boks.rs:32:12
[INFO] [stdout]    |
[INFO] [stdout] 31 | impl<T> Boks<T> {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] 32 |     pub fn ny(t: T) -> Self {
[INFO] [stdout]    |            ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `our_flatten` is never used
[INFO] [stdout]  --> src/iterators/iterator.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait IteratorExt: Iterator + Sized {
[INFO] [stdout]   |           ----------- method in this trait
[INFO] [stdout] 2 |     fn our_flatten(self) -> Flatten<Self>
[INFO] [stdout]   |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strtok` is never used
[INFO] [stdout]  --> src/subtyping_and_variance/strtok.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub fn strtok<'a>(s: &'_ mut &'a str, delimiter: char) -> &'a str {
[INFO] [stdout]   |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `core::str::<impl str>::len` that must be used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:52:5
[INFO] [stdout]    |
[INFO] [stdout] 52 |     s.len();
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let _ = s.len();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary allocation, use `&` instead
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:66:29
[INFO] [stdout]    |
[INFO] [stdout] 66 |     slice_of_trait_object(&[Box::new("hello").as_ref()])
[INFO] [stdout]    |                             ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_allocation)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Box::<T>::from_raw` that must be used
[INFO] [stdout]   --> src/drop_check/boks.rs:10:18
[INFO] [stdout]    |
[INFO] [stdout] 10 |         unsafe { Box::from_raw(self.p) };
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: call `drop(Box::from_raw(ptr))` if you intend to drop the `Box`
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 10 |         unsafe { let _ = Box::from_raw(self.p); };
[INFO] [stdout]    |                  +++++++                      +
[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/smart_pointers_and_interior_mutability/rc.rs:64:13
[INFO] [stdout]    |
[INFO] [stdout] 64 |             drop(inner);
[INFO] [stdout]    |             ^^^^^-----^
[INFO] [stdout]    |                  |
[INFO] [stdout]    |                  argument has type `&RcInner<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] 64 -             drop(inner);
[INFO] [stdout] 64 +             let _ = inner;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 21 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `boks`
[INFO] [stdout]   --> src/drop_check/boks.rs:52:13
[INFO] [stdout]    |
[INFO] [stdout] 52 |         let boks = Boks::ny(&mut y);
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_boks`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `hei` and `not_ok` are never used
[INFO] [stdout]  --> src/dispatch_and_fat_pointers/main.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait Hei {
[INFO] [stdout]   |           --- associated items in this trait
[INFO] [stdout] 2 |     fn hei(&self);
[INFO] [stdout]   |        ^^^
[INFO] [stdout] 3 |
[INFO] [stdout] 4 |     fn not_ok()
[INFO] [stdout]   |        ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strlen` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:31:4
[INFO] [stdout]    |
[INFO] [stdout] 31 | fn strlen(s: impl AsRef<str>) -> usize {
[INFO] [stdout]    |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `strlen_dyn` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:35:4
[INFO] [stdout]    |
[INFO] [stdout] 35 | fn strlen_dyn(s: Box<dyn AsRef<str>>) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `bool_then` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:39:8
[INFO] [stdout]    |
[INFO] [stdout] 39 | pub fn bool_then<T>(b: bool, f: impl FnOnce() -> T) -> Option<T> {
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `HeiAsRef` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:47:11
[INFO] [stdout]    |
[INFO] [stdout] 47 | pub trait HeiAsRef: Hei + AsRef<str> {}
[INFO] [stdout]    |           ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `baz` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:49:8
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn baz(s: &dyn HeiAsRef) {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `slice_of_trait_object` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:55:8
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub fn slice_of_trait_object(v: &[&dyn AsRef<str>]) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `main` is never used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:61:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | pub fn main() {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `our_flatten` is never used
[INFO] [stdout]  --> src/iterators/iterator.rs:2:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub trait IteratorExt: Iterator + Sized {
[INFO] [stdout]   |           ----------- method in this trait
[INFO] [stdout] 2 |     fn our_flatten(self) -> Flatten<Self>
[INFO] [stdout]   |        ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `core::str::<impl str>::len` that must be used
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:52:5
[INFO] [stdout]    |
[INFO] [stdout] 52 |     s.len();
[INFO] [stdout]    |     ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let _ = s.len();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary allocation, use `&` instead
[INFO] [stdout]   --> src/dispatch_and_fat_pointers/main.rs:66:29
[INFO] [stdout]    |
[INFO] [stdout] 66 |     slice_of_trait_object(&[Box::new("hello").as_ref()])
[INFO] [stdout]    |                             ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_allocation)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Box::<T>::from_raw` that must be used
[INFO] [stdout]   --> src/drop_check/boks.rs:10:18
[INFO] [stdout]    |
[INFO] [stdout] 10 |         unsafe { Box::from_raw(self.p) };
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: call `drop(Box::from_raw(ptr))` if you intend to drop the `Box`
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 10 |         unsafe { let _ = Box::from_raw(self.p); };
[INFO] [stdout]    |                  +++++++                      +
[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/smart_pointers_and_interior_mutability/rc.rs:64:13
[INFO] [stdout]    |
[INFO] [stdout] 64 |             drop(inner);
[INFO] [stdout]    |             ^^^^^-----^
[INFO] [stdout]    |                  |
[INFO] [stdout]    |                  argument has type `&RcInner<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] 64 -             drop(inner);
[INFO] [stdout] 64 +             let _ = inner;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 15 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.30s
[INFO] running `Command { std: "docker" "inspect" "8d7e3a1e58a67e82fd3f90df6923f2c103709e04f6b9e89b56eed7d92d90af41", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8d7e3a1e58a67e82fd3f90df6923f2c103709e04f6b9e89b56eed7d92d90af41", kill_on_drop: false }`
[INFO] [stdout] 8d7e3a1e58a67e82fd3f90df6923f2c103709e04f6b9e89b56eed7d92d90af41