[INFO] cloning repository https://github.com/ShantanuVichare/Learning-Rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ShantanuVichare/Learning-Rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShantanuVichare%2FLearning-Rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShantanuVichare%2FLearning-Rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0108b0191fd9d82ffc044406f73331de233f40a1
[INFO] checking ShantanuVichare/Learning-Rust against try#09eeb2bacb9b40b2ed1d47f03177442c0632cda1 for pr-157710
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FShantanuVichare%2FLearning-Rust" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/ShantanuVichare/Learning-Rust
[INFO] finished tweaking git repo https://github.com/ShantanuVichare/Learning-Rust
[INFO] tweaked toml for git repo https://github.com/ShantanuVichare/Learning-Rust written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/ShantanuVichare/Learning-Rust on toolchain 09eeb2bacb9b40b2ed1d47f03177442c0632cda1
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+09eeb2bacb9b40b2ed1d47f03177442c0632cda1" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/ShantanuVichare/Learning-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" "+09eeb2bacb9b40b2ed1d47f03177442c0632cda1" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f
[INFO] running `Command { std: "docker" "start" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f" "/opt/rustwide/cargo-home/bin/cargo" "+09eeb2bacb9b40b2ed1d47f03177442c0632cda1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-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" "-w" "/opt/rustwide/workdir" "--user" "0:0" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f" "/opt/rustwide/cargo-home/bin/cargo" "+09eeb2bacb9b40b2ed1d47f03177442c0632cda1" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling libc v0.2.68
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking rust_learner v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/sm_pointers.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |         let b = Box::new(50); // b is stored on Stack where as the value 50 is stored on Heap
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list`
[INFO] [stdout]   --> src/sm_pointers.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let list = Cons(1,Box::new(Cons(2,Box::new(Cons(3,Box::new(Nil))))));
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_list`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/sm_pointers.rs:89:13
[INFO] [stdout]    |
[INFO] [stdout] 89 |         let mut a = Rc::new(Cons(5,Rc::new(Cons(6,Rc::new(Nil)))));
[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: `b`
[INFO] [stdout]   --> src/sm_pointers.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |         let b = Cons(3,Rc::clone(&a)); // Similar to a.clone() in this case but Rc::clone() is visually distinguishable
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/sm_pointers.rs:93:13
[INFO] [stdout]    |
[INFO] [stdout] 93 |         let c = Cons(4,a.clone());
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:21:10
[INFO] [stdout]    |
[INFO] [stdout] 21 |     enum List {
[INFO] [stdout]    |          ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]   --> src/sm_pointers.rs:26:12
[INFO] [stdout]    |
[INFO] [stdout] 26 |     struct MyBox<T> (T);
[INFO] [stdout]    |            ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:29:12
[INFO] [stdout]    |
[INFO] [stdout] 28 |     impl<T> MyBox<T> {
[INFO] [stdout]    |     ---------------- associated function in this implementation
[INFO] [stdout] 29 |         fn new(x: T) -> MyBox<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `run` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:50:12
[INFO] [stdout]    |
[INFO] [stdout] 50 |     pub fn run() {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:82:10
[INFO] [stdout]    |
[INFO] [stdout] 82 |     enum List {
[INFO] [stdout]    |          ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `run` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:88:12
[INFO] [stdout]    |
[INFO] [stdout] 88 |     pub fn run() {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `clone` that must be used
[INFO] [stdout]   --> src/sm_pointers.rs:95:9
[INFO] [stdout]    |
[INFO] [stdout] 95 | ...   Rc::clone(&a); // This will first increase the count, then the cloned reference will be go out of scope and decrease the count...
[INFO] [stdout]    |       ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: cloning is often expensive and is not expected to have side effects
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 95 |         let _ = Rc::clone(&a); // This will first increase the count, then the cloned reference will be go out of scope and decrease the count, so count will remain unchanged
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/sm_pointers.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |         let b = Box::new(50); // b is stored on Stack where as the value 50 is stored on Heap
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list`
[INFO] [stdout]   --> src/sm_pointers.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let list = Cons(1,Box::new(Cons(2,Box::new(Cons(3,Box::new(Nil))))));
[INFO] [stdout]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_list`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/sm_pointers.rs:89:13
[INFO] [stdout]    |
[INFO] [stdout] 89 |         let mut a = Rc::new(Cons(5,Rc::new(Cons(6,Rc::new(Nil)))));
[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: `b`
[INFO] [stdout]   --> src/sm_pointers.rs:91:13
[INFO] [stdout]    |
[INFO] [stdout] 91 |         let b = Cons(3,Rc::clone(&a)); // Similar to a.clone() in this case but Rc::clone() is visually distinguishable
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/sm_pointers.rs:93:13
[INFO] [stdout]    |
[INFO] [stdout] 93 |         let c = Cons(4,a.clone());
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:21:10
[INFO] [stdout]    |
[INFO] [stdout] 21 |     enum List {
[INFO] [stdout]    |          ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MyBox` is never constructed
[INFO] [stdout]   --> src/sm_pointers.rs:26:12
[INFO] [stdout]    |
[INFO] [stdout] 26 |     struct MyBox<T> (T);
[INFO] [stdout]    |            ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:29:12
[INFO] [stdout]    |
[INFO] [stdout] 28 |     impl<T> MyBox<T> {
[INFO] [stdout]    |     ---------------- associated function in this implementation
[INFO] [stdout] 29 |         fn new(x: T) -> MyBox<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `run` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:50:12
[INFO] [stdout]    |
[INFO] [stdout] 50 |     pub fn run() {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:82:10
[INFO] [stdout]    |
[INFO] [stdout] 82 |     enum List {
[INFO] [stdout]    |          ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `run` is never used
[INFO] [stdout]   --> src/sm_pointers.rs:88:12
[INFO] [stdout]    |
[INFO] [stdout] 88 |     pub fn run() {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `clone` that must be used
[INFO] [stdout]   --> src/sm_pointers.rs:95:9
[INFO] [stdout]    |
[INFO] [stdout] 95 | ...   Rc::clone(&a); // This will first increase the count, then the cloned reference will be go out of scope and decrease the count...
[INFO] [stdout]    |       ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: cloning is often expensive and is not expected to have side effects
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 95 |         let _ = Rc::clone(&a); // This will first increase the count, then the cloned reference will be go out of scope and decrease the count, so count will remain unchanged
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.03s
[INFO] running `Command { std: "docker" "inspect" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f", kill_on_drop: false }`
[INFO] [stdout] 6afd2515fa74897dff2a47b2550eb5ff8607a44478da9c70e6a17bb11de6482f
