[INFO] fetching crate persist-o-vec 0.3.1...
[INFO] checking persist-o-vec-0.3.1 against master#e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682 for beta-170-4
[INFO] extracting crate persist-o-vec 0.3.1 into /workspace/builds/worker-2-tc2/source
[INFO] validating manifest of crates.io crate persist-o-vec 0.3.1 on toolchain e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate persist-o-vec 0.3.1
[INFO] finished tweaking crates.io crate persist-o-vec 0.3.1
[INFO] tweaked toml for crates.io crate persist-o-vec 0.3.1 written to /workspace/builds/worker-2-tc2/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" __CARGO_TEST_CHANNEL_OVERRIDE_DO_NOT_USE_THIS="nightly" "/workspace/cargo-home/bin/cargo" "+e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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@sha256:5ff2268d62e97bff2cde7d5815dd6ed5b47097566f13b8d0ca110b04b60e07ed" "/opt/rustwide/cargo-home/bin/cargo" "+e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4b39895d3ff170230619bf1ad16c9090dd94f38b834230bc334bee5fb37a67d9
[INFO] running `Command { std: "docker" "start" "-a" "4b39895d3ff170230619bf1ad16c9090dd94f38b834230bc334bee5fb37a67d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4b39895d3ff170230619bf1ad16c9090dd94f38b834230bc334bee5fb37a67d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b39895d3ff170230619bf1ad16c9090dd94f38b834230bc334bee5fb37a67d9", kill_on_drop: false }`
[INFO] [stdout] 4b39895d3ff170230619bf1ad16c9090dd94f38b834230bc334bee5fb37a67d9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/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@sha256:5ff2268d62e97bff2cde7d5815dd6ed5b47097566f13b8d0ca110b04b60e07ed" "/opt/rustwide/cargo-home/bin/cargo" "+e6e4f7ed1589e03bc2f6c5931c1a72e7947e8682" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4d7c4fb107e174246577a51287373cd0bba760edf618f46f4768cfebddd968a1
[INFO] running `Command { std: "docker" "start" "-a" "4d7c4fb107e174246577a51287373cd0bba760edf618f46f4768cfebddd968a1", kill_on_drop: false }`
[INFO] [stderr]     Checking bencher v0.1.5
[INFO] [stderr]     Checking persist-o-vec v0.3.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:255:29
[INFO] [stdout]     |
[INFO] [stdout] 255 |                 if let Some(mut into_used) = into_used.as_mut() {
[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/lib.rs:285:25
[INFO] [stdout]     |
[INFO] [stdout] 285 |             if let Some(mut prev) = slot.prev.as_mut() {
[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/lib.rs:286:29
[INFO] [stdout]     |
[INFO] [stdout] 286 |                 if let Some(mut next) = slot.next.as_mut() {
[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/lib.rs:293:32
[INFO] [stdout]     |
[INFO] [stdout] 293 |             } else if let Some(mut next) = slot.next.as_mut() {
[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/lib.rs:311:17
[INFO] [stdout]     |
[INFO] [stdout] 311 |             let mut slot = &mut self.entries[index];
[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/lib.rs:340:29
[INFO] [stdout]     |
[INFO] [stdout] 340 |                 if let Some(mut next) = (*slot).next.as_mut() {
[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/lib.rs:356:13
[INFO] [stdout]     |
[INFO] [stdout] 356 |         let mut slot = &mut self.entries[index];
[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] [stdout] error: couldn't read benches/bench.rs: No such file or directory (os error 2)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `persist-o-vec` (bench "bench") due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:255:29
[INFO] [stdout]     |
[INFO] [stdout] 255 |                 if let Some(mut into_used) = into_used.as_mut() {
[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/lib.rs:285:25
[INFO] [stdout]     |
[INFO] [stdout] 285 |             if let Some(mut prev) = slot.prev.as_mut() {
[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/lib.rs:286:29
[INFO] [stdout]     |
[INFO] [stdout] 286 |                 if let Some(mut next) = slot.next.as_mut() {
[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/lib.rs:293:32
[INFO] [stdout]     |
[INFO] [stdout] 293 |             } else if let Some(mut next) = slot.next.as_mut() {
[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/lib.rs:311:17
[INFO] [stdout]     |
[INFO] [stdout] 311 |             let mut slot = &mut self.entries[index];
[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/lib.rs:340:29
[INFO] [stdout]     |
[INFO] [stdout] 340 |                 if let Some(mut next) = (*slot).next.as_mut() {
[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/lib.rs:356:13
[INFO] [stdout]     |
[INFO] [stdout] 356 |         let mut slot = &mut self.entries[index];
[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] running `Command { std: "docker" "inspect" "4d7c4fb107e174246577a51287373cd0bba760edf618f46f4768cfebddd968a1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d7c4fb107e174246577a51287373cd0bba760edf618f46f4768cfebddd968a1", kill_on_drop: false }`
[INFO] [stdout] 4d7c4fb107e174246577a51287373cd0bba760edf618f46f4768cfebddd968a1
