[INFO] fetching crate sknife 0.2.2...
[INFO] checking sknife-0.2.2 against master#5e3f1b148db5bfa27fee52464ae1f5d34c49d77b for pr-75502
[INFO] extracting crate sknife 0.2.2 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate sknife 0.2.2 on toolchain 5e3f1b148db5bfa27fee52464ae1f5d34c49d77b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate sknife 0.2.2
[INFO] finished tweaking crates.io crate sknife 0.2.2
[INFO] tweaked toml for crates.io crate sknife 0.2.2 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:e18d859f9e32a1da89bc7b2d7d51e13b57342044d1295d9fc0dd0068c58eb3d1" "/opt/rustwide/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 80b93cfd87dfb2a2dc57f82e439fb20ac2fe41adc85727a2dd22ca38cfe9ad17
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "80b93cfd87dfb2a2dc57f82e439fb20ac2fe41adc85727a2dd22ca38cfe9ad17", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "80b93cfd87dfb2a2dc57f82e439fb20ac2fe41adc85727a2dd22ca38cfe9ad17", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "80b93cfd87dfb2a2dc57f82e439fb20ac2fe41adc85727a2dd22ca38cfe9ad17", kill_on_drop: false }`
[INFO] [stdout] 80b93cfd87dfb2a2dc57f82e439fb20ac2fe41adc85727a2dd22ca38cfe9ad17
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:e18d859f9e32a1da89bc7b2d7d51e13b57342044d1295d9fc0dd0068c58eb3d1" "/opt/rustwide/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b3e96957197a88f75872c5547903cbcd8b2cbf2b8947b16934b4b72b7d4b633d
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "b3e96957197a88f75872c5547903cbcd8b2cbf2b8947b16934b4b72b7d4b633d", kill_on_drop: false }`
[INFO] [stderr]     Checking sknife v0.2.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/collection/any.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/collection/count.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/collection/find.rs:39:9
[INFO] [stdout]    |
[INFO] [stdout] 39 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::*`
[INFO] [stdout]   --> src/collection/flatmap.rs:35:9
[INFO] [stdout]    |
[INFO] [stdout] 35 |     use super::*;
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std`
[INFO] [stdout]  --> src/collection/zip.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std;
[INFO] [stdout]   |     ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std`
[INFO] [stdout]  --> src/collection/zip.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std;
[INFO] [stdout]   |     ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/any.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_attributes)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/any.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/count.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/count.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/find.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/find.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/flatmap.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/flatmap.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/map.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/map.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/reduce.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/reduce.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/zip.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/zip.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 19 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/collection/any.rs:44:13
[INFO] [stdout]    |
[INFO] [stdout] 44 |         let mut list = vec![];
[INFO] [stdout]    |             ----^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/collection/any.rs:54:13
[INFO] [stdout]    |
[INFO] [stdout] 54 |         let mut list = vec![1, 2, 3, 4];
[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/collection/count.rs:32:13
[INFO] [stdout]    |
[INFO] [stdout] 32 |         let mut list: Vec<i32> = vec![];
[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]  --> tests/collections_any.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     let mut list = vec![1, 2, 3, 4];
[INFO] [stdout]   |         ----^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/collection/count.rs:38:13
[INFO] [stdout]    |
[INFO] [stdout] 38 |         let mut list = vec![1, 2, 3, 4];
[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/collection/find.rs:43:13
[INFO] [stdout]    |
[INFO] [stdout] 43 |         let mut list = vec![];
[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/collection/find.rs:53:13
[INFO] [stdout]    |
[INFO] [stdout] 53 |         let mut list = vec![1, 2, 3, 4];
[INFO] [stdout]    |             ----^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/any.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_attributes)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/any.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/count.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/count.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/find.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/find.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/flatmap.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/flatmap.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/map.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/map.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/reduce.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/reduce.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused attribute
[INFO] [stdout]  --> src/collection/zip.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: crate-level attribute should be in the root module
[INFO] [stdout]  --> src/collection/zip.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![crate_name = "sknife"]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 21 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> benches/collections_map.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 15 |         let mut slice = list.as_mut_slice();
[INFO] [stdout]    |             ----^^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> benches/collections_flatmap.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 15 |         let mut slice: &mut [i32] = list.as_mut_slice();
[INFO] [stdout]    |             ----^^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> benches/collections_map.rs:16:13
[INFO] [stdout]    |
[INFO] [stdout] 16 |         let mut plus_one = |x: i32| x + 1;
[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]   --> benches/collections_flatmap.rs:16:13
[INFO] [stdout]    |
[INFO] [stdout] 16 |         let mut plus_one = |x: &mut i32| vec![*x];
[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]   --> benches/collections_map.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |         let mut list = 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]   --> benches/collections_map.rs:23:13
[INFO] [stdout]    |
[INFO] [stdout] 23 |         let mut plus_one = |x| x + 1;
[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]  --> tests/collections_find.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     let mut list = vec![1, 3, 4, 7, 3, 9];
[INFO] [stdout]   |         ----^^^^
[INFO] [stdout]   |         |
[INFO] [stdout]   |         help: remove this `mut`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> benches/collections_flatmap.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |         let mut list = 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]   --> benches/collections_flatmap.rs:23:13
[INFO] [stdout]    |
[INFO] [stdout] 23 |         let mut plus_one = |x| vec![x];
[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]   --> benches/collections_reduce.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 15 |         let mut fact = |acc: i32, x| acc * x;
[INFO] [stdout]    |             ----^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> benches/collections_reduce.rs:21:13
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let mut list: Vec<i32> = (1..50).collect();
[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]   --> benches/collections_reduce.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |         let mut fact = |acc: i32, x| acc * x;
[INFO] [stdout]    |             ----^^^^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.95s
[INFO] running `Command { std: "docker" "inspect" "b3e96957197a88f75872c5547903cbcd8b2cbf2b8947b16934b4b72b7d4b633d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b3e96957197a88f75872c5547903cbcd8b2cbf2b8947b16934b4b72b7d4b633d", kill_on_drop: false }`
[INFO] [stdout] b3e96957197a88f75872c5547903cbcd8b2cbf2b8947b16934b4b72b7d4b633d