[INFO] fetching crate mwmatching 0.1.1...
[INFO] checking mwmatching-0.1.1 against master#936f2600b6c903b04387f74ed5cbce88bb06d243 for pr-91141
[INFO] extracting crate mwmatching 0.1.1 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate mwmatching 0.1.1 on toolchain 936f2600b6c903b04387f74ed5cbce88bb06d243
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mwmatching 0.1.1
[INFO] finished tweaking crates.io crate mwmatching 0.1.1
[INFO] tweaked toml for crates.io crate mwmatching 0.1.1 written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cb76e88b9a458e2ad640799208af3b548e201aa833780745139806ab5fe3f32c
[INFO] running `Command { std: "docker" "start" "-a" "cb76e88b9a458e2ad640799208af3b548e201aa833780745139806ab5fe3f32c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cb76e88b9a458e2ad640799208af3b548e201aa833780745139806ab5fe3f32c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cb76e88b9a458e2ad640799208af3b548e201aa833780745139806ab5fe3f32c", kill_on_drop: false }`
[INFO] [stdout] cb76e88b9a458e2ad640799208af3b548e201aa833780745139806ab5fe3f32c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9ad51c17eaa52a6411b16c3f906d855b2264e9c123e9ac417f8b016abc5b80fe
[INFO] running `Command { std: "docker" "start" "-a" "9ad51c17eaa52a6411b16c3f906d855b2264e9c123e9ac417f8b016abc5b80fe", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking mwmatching v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> src/lib.rs:1083:60
[INFO] [stdout]      |
[INFO] [stdout] 1083 |     let actual_index = if index>= 0 {index as usize} else {(v.len()-(-index) as usize)};
[INFO] [stdout]      |                                                            ^                         ^
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1083 -     let actual_index = if index>= 0 {index as usize} else {(v.len()-(-index) as usize)};
[INFO] [stdout] 1083 +     let actual_index = if index>= 0 {index as usize} else {v.len()-(-index) as usize};
[INFO] [stdout]      | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> src/lib.rs:1083:60
[INFO] [stdout]      |
[INFO] [stdout] 1083 |     let actual_index = if index>= 0 {index as usize} else {(v.len()-(-index) as usize)};
[INFO] [stdout]      |                                                            ^                         ^
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout] 1083 -     let actual_index = if index>= 0 {index as usize} else {(v.len()-(-index) as usize)};
[INFO] [stdout] 1083 +     let actual_index = if index>= 0 {index as usize} else {v.len()-(-index) as usize};
[INFO] [stdout]      | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:744:25
[INFO] [stdout]     |
[INFO] [stdout] 744 |                     let mut k = p / 2;
[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:852:29
[INFO] [stdout]     |
[INFO] [stdout] 852 |                         let mut k = p / 2;
[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:744:25
[INFO] [stdout]     |
[INFO] [stdout] 744 |                     let mut k = p / 2;
[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:852:29
[INFO] [stdout]     |
[INFO] [stdout] 852 |                         let mut k = p / 2;
[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] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0463]: can't find crate for `rand`
[INFO] [stdout]  --> examples/largedata/main.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | extern crate rand;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^ can't find crate
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0463`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `mwmatching` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "9ad51c17eaa52a6411b16c3f906d855b2264e9c123e9ac417f8b016abc5b80fe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9ad51c17eaa52a6411b16c3f906d855b2264e9c123e9ac417f8b016abc5b80fe", kill_on_drop: false }`
[INFO] [stdout] 9ad51c17eaa52a6411b16c3f906d855b2264e9c123e9ac417f8b016abc5b80fe