[INFO] cloning repository https://github.com/morozik11/lessons
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/morozik11/lessons" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorozik11%2Flessons", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorozik11%2Flessons'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c4266c7c80d092361a5a0c19a712c1bb0bc0e908
[INFO] checking morozik11/lessons against try#8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8 for pr-82565
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmorozik11%2Flessons" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/morozik11/lessons on toolchain 8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/morozik11/lessons
[INFO] finished tweaking git repo https://github.com/morozik11/lessons
[INFO] tweaked toml for git repo https://github.com/morozik11/lessons written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/morozik11/lessons already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 54a15aa21d3df62b9271c5c84f0d9e29345f4cecc9cdd7fc287c7eae0b94cebb
[INFO] running `Command { std: "docker" "start" "-a" "54a15aa21d3df62b9271c5c84f0d9e29345f4cecc9cdd7fc287c7eae0b94cebb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "54a15aa21d3df62b9271c5c84f0d9e29345f4cecc9cdd7fc287c7eae0b94cebb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "54a15aa21d3df62b9271c5c84f0d9e29345f4cecc9cdd7fc287c7eae0b94cebb", kill_on_drop: false }`
[INFO] [stdout] 54a15aa21d3df62b9271c5c84f0d9e29345f4cecc9cdd7fc287c7eae0b94cebb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7782c6a9d9a483121f575d4fa74aeec4948e5b9ed8dba4be2a20a2d1d5e79183
[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" "7782c6a9d9a483121f575d4fa74aeec4948e5b9ed8dba4be2a20a2d1d5e79183", kill_on_drop: false }`
[INFO] [stderr]     Checking alg v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::mem`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `closure_annotated`
[INFO] [stdout]    --> src/main.rs:140:9
[INFO] [stdout]     |
[INFO] [stdout] 140 |     let mut closure_annotated = |x: &mut u32| {
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_closure_annotated`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:54:13
[INFO] [stdout]    |
[INFO] [stdout] 54 |         let result = self.head.as_mut().map(|vertex| vertex.push_left(elem));
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:58:13
[INFO] [stdout]    |
[INFO] [stdout] 58 |         let result = self.head.as_mut().map(|vertex| vertex.push_right(elem));
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::mem`
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:47:36
[INFO] [stdout]    |
[INFO] [stdout] 47 |     pub fn recursion<F>(&mut self, mut f: &mut F)
[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/main.rs:81:36
[INFO] [stdout]    |
[INFO] [stdout] 81 |     pub fn recursion<F>(&mut self, mut f: &mut F)
[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/main.rs:140:9
[INFO] [stdout]     |
[INFO] [stdout] 140 |     let mut closure_annotated = |x: &mut u32| {
[INFO] [stdout]     |         ----^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `closure_annotated`
[INFO] [stdout]    --> src/main.rs:140:9
[INFO] [stdout]     |
[INFO] [stdout] 140 |     let mut closure_annotated = |x: &mut u32| {
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_closure_annotated`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:54:13
[INFO] [stdout]    |
[INFO] [stdout] 54 |         let result = self.head.as_mut().map(|vertex| vertex.push_left(elem));
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:58:13
[INFO] [stdout]    |
[INFO] [stdout] 58 |         let result = self.head.as_mut().map(|vertex| vertex.push_right(elem));
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:47:36
[INFO] [stdout]    |
[INFO] [stdout] 47 |     pub fn recursion<F>(&mut self, mut f: &mut F)
[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/main.rs:81:36
[INFO] [stdout]    |
[INFO] [stdout] 81 |     pub fn recursion<F>(&mut self, mut f: &mut F)
[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/main.rs:140:9
[INFO] [stdout]     |
[INFO] [stdout] 140 |     let mut closure_annotated = |x: &mut u32| {
[INFO] [stdout]     |         ----^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.78s
[INFO] running `Command { std: "docker" "inspect" "7782c6a9d9a483121f575d4fa74aeec4948e5b9ed8dba4be2a20a2d1d5e79183", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7782c6a9d9a483121f575d4fa74aeec4948e5b9ed8dba4be2a20a2d1d5e79183", kill_on_drop: false }`
[INFO] [stdout] 7782c6a9d9a483121f575d4fa74aeec4948e5b9ed8dba4be2a20a2d1d5e79183