[INFO] updating cached repository https://github.com/ghotiphud/rust-intro
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c72640c3eb4a803d29bd3eb29798bcb85e9b4054
[INFO] checking ghotiphud/rust-intro against try#e4dba30b9b475d8750370c4dfb49b6541990904d for pr-71393
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fghotiphud%2Frust-intro" "/workspace/builds/worker-7/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ghotiphud/rust-intro on toolchain e4dba30b9b475d8750370c4dfb49b6541990904d
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/ghotiphud/rust-intro
[INFO] finished tweaking git repo https://github.com/ghotiphud/rust-intro
[INFO] tweaked toml for git repo https://github.com/ghotiphud/rust-intro written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/ghotiphud/rust-intro already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+e4dba30b9b475d8750370c4dfb49b6541990904d" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 63a719673205fa67d8e49def367a72f20a452947201203c7f1eb538e08ebf16b
[INFO] running `"docker" "start" "-a" "63a719673205fa67d8e49def367a72f20a452947201203c7f1eb538e08ebf16b"`
[INFO] [stderr]     Checking rust_intro v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]  --> src/safety.rs:3:9
[INFO] [stderr]   |
[INFO] [stderr] 3 |     let y = &x[0]; //Borrow(Reference) the first element of x
[INFO] [stderr]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]  --> src/safety.rs:2:9
[INFO] [stderr]   |
[INFO] [stderr] 2 |     let mut x = vec![10, 20]; //Create vec owned by x
[INFO] [stderr]   |         ----^
[INFO] [stderr]   |         |
[INFO] [stderr]   |         help: remove this `mut`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `y` is never read
[INFO] [stderr]   --> src/types.rs:17:9
[INFO] [stderr]    |
[INFO] [stderr] 17 |     let mut y = x as i64;
[INFO] [stderr]    |         ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary `unsafe` block
[INFO] [stderr]   --> src/types.rs:71:9
[INFO] [stderr]    |
[INFO] [stderr] 71 |         unsafe {
[INFO] [stderr]    |         ^^^^^^ unnecessary `unsafe` block
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_unsafe)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/types.rs:54:16
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Two`
[INFO] [stderr]   --> src/types.rs:54:27
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                           ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Three`
[INFO] [stderr]   --> src/types.rs:54:32
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                                ^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `y` is never read
[INFO] [stderr]   --> src/types.rs:17:9
[INFO] [stderr]    |
[INFO] [stderr] 17 |     let mut y = x as i64;
[INFO] [stderr]    |         ^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary `unsafe` block
[INFO] [stderr]   --> src/types.rs:71:9
[INFO] [stderr]    |
[INFO] [stderr] 71 |         unsafe {
[INFO] [stderr]    |         ^^^^^^ unnecessary `unsafe` block
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_unsafe)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/types.rs:54:16
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Two`
[INFO] [stderr]   --> src/types.rs:54:27
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                           ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Three`
[INFO] [stderr]   --> src/types.rs:54:32
[INFO] [stderr]    |
[INFO] [stderr] 54 | enum Options { None, One, Two, Three }
[INFO] [stderr]    |                                ^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: 2 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: 5 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: 5 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::iter::Iterator::collect` that must be used
[INFO] [stderr]    --> src/concurrent.rs:140:5
[INFO] [stderr]     |
[INFO] [stderr] 140 |     handles.into_iter().map(|h| h.join().unwrap()).collect::<Vec<_>>();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]  --> src/main.rs:5:9
[INFO] [stderr]   |
[INFO] [stderr] 5 |     let y = &x[0]; //Borrow(Reference) the first element of x
[INFO] [stderr]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator`
[INFO] [stderr]  --> src/main.rs:9:4
[INFO] [stderr]   |
[INFO] [stderr] 9 | fn iterator() {
[INFO] [stderr]   |    ^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `sum_pos`
[INFO] [stderr]   --> src/main.rs:16:4
[INFO] [stderr]    |
[INFO] [stderr] 16 | fn sum_pos(v: &Vec<i32>) -> i32 {
[INFO] [stderr]    |    ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused return value of `std::iter::Iterator::collect` that must be used
[INFO] [stderr]    --> src/concurrent.rs:140:5
[INFO] [stderr]     |
[INFO] [stderr] 140 |     handles.into_iter().map(|h| h.join().unwrap()).collect::<Vec<_>>();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: if you really need to exhaust the iterator, consider `.for_each(drop)` instead
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]  --> src/main.rs:5:9
[INFO] [stderr]   |
[INFO] [stderr] 5 |     let y = &x[0]; //Borrow(Reference) the first element of x
[INFO] [stderr]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `iterator`
[INFO] [stderr]  --> src/main.rs:9:4
[INFO] [stderr]   |
[INFO] [stderr] 9 | fn iterator() {
[INFO] [stderr]   |    ^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `sum_pos`
[INFO] [stderr]   --> src/main.rs:16:4
[INFO] [stderr]    |
[INFO] [stderr] 16 | fn sum_pos(v: &Vec<i32>) -> i32 {
[INFO] [stderr]    |    ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `y`
[INFO] [stderr]  --> src/safety.rs:3:9
[INFO] [stderr]   |
[INFO] [stderr] 3 |     let y = &x[0]; //Borrow(Reference) the first element of x
[INFO] [stderr]   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 3 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]  --> src/safety.rs:2:9
[INFO] [stderr]   |
[INFO] [stderr] 2 |     let mut x = vec![10, 20]; //Create vec owned by x
[INFO] [stderr]   |         ----^
[INFO] [stderr]   |         |
[INFO] [stderr]   |         help: remove this `mut`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 3 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: 2 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.52s
[INFO] running `"docker" "inspect" "63a719673205fa67d8e49def367a72f20a452947201203c7f1eb538e08ebf16b"`
[INFO] running `"docker" "rm" "-f" "63a719673205fa67d8e49def367a72f20a452947201203c7f1eb538e08ebf16b"`
[INFO] [stdout] 63a719673205fa67d8e49def367a72f20a452947201203c7f1eb538e08ebf16b