[INFO] updating cached repository KuabeM/working-time-calculator
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/KuabeM/working-time-calculator
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/KuabeM/working-time-calculator" "work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/KuabeM/working-time-calculator" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/KuabeM/working-time-calculator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/KuabeM/working-time-calculator'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] ae8e54c25caec34c3fbb549d8e2c321abe6004e0
[INFO] sha for GitHub repo KuabeM/working-time-calculator: ae8e54c25caec34c3fbb549d8e2c321abe6004e0
[INFO] validating manifest of KuabeM/working-time-calculator on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of KuabeM/working-time-calculator on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing KuabeM/working-time-calculator
[INFO] finished frobbing KuabeM/working-time-calculator
[INFO] frobbed toml for KuabeM/working-time-calculator written to work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator/Cargo.toml
[INFO] started frobbing KuabeM/working-time-calculator
[INFO] finished frobbing KuabeM/working-time-calculator
[INFO] frobbed toml for KuabeM/working-time-calculator written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/KuabeM/working-time-calculator/Cargo.toml
[INFO] crate KuabeM/working-time-calculator already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing KuabeM/working-time-calculator against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 3ea996101f46a54704b28b5cfbec425cdfa87c6503d7c1da60a06678a3742875
[INFO] running `"docker" "start" "-a" "3ea996101f46a54704b28b5cfbec425cdfa87c6503d7c1da60a06678a3742875"`
[INFO] [stderr]    Compiling working-time-calc v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: value assigned to `content` is never read
[INFO] [stderr]    --> src/main.rs:117:13
[INFO] [stderr]     |
[INFO] [stderr] 117 |     let mut content = String::new();
[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: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:108:9
[INFO] [stderr]     |
[INFO] [stderr] 108 |     let mut content_opt = match read_file_to_string( &file_name) {
[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]     Finished dev [unoptimized + debuginfo] target(s) in 1.67s
[INFO] running `"docker" "inspect" "3ea996101f46a54704b28b5cfbec425cdfa87c6503d7c1da60a06678a3742875"`
[INFO] running `"docker" "rm" "-f" "3ea996101f46a54704b28b5cfbec425cdfa87c6503d7c1da60a06678a3742875"`
[INFO] [stdout] 3ea996101f46a54704b28b5cfbec425cdfa87c6503d7c1da60a06678a3742875
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] f0c7d9dd0f555d60ab385f62da391ecf5109190659079eac2347081c307d6334
[INFO] running `"docker" "start" "-a" "f0c7d9dd0f555d60ab385f62da391ecf5109190659079eac2347081c307d6334"`
[INFO] [stderr]    Compiling working-time-calc v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: value assigned to `content` is never read
[INFO] [stderr]    --> src/main.rs:117:13
[INFO] [stderr]     |
[INFO] [stderr] 117 |     let mut content = String::new();
[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: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:108:9
[INFO] [stderr]     |
[INFO] [stderr] 108 |     let mut content_opt = match read_file_to_string( &file_name) {
[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]     Finished dev [unoptimized + debuginfo] target(s) in 0.56s
[INFO] running `"docker" "inspect" "f0c7d9dd0f555d60ab385f62da391ecf5109190659079eac2347081c307d6334"`
[INFO] running `"docker" "rm" "-f" "f0c7d9dd0f555d60ab385f62da391ecf5109190659079eac2347081c307d6334"`
[INFO] [stdout] f0c7d9dd0f555d60ab385f62da391ecf5109190659079eac2347081c307d6334
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/KuabeM/working-time-calculator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "test" "--frozen"`
[INFO] [stdout] e95d1e271f239008fdac1273410b526c79c278512b985de66fea6eb883ca3b3d
[INFO] running `"docker" "start" "-a" "e95d1e271f239008fdac1273410b526c79c278512b985de66fea6eb883ca3b3d"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/working_time_calc-c9436cd237ceb98c
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "e95d1e271f239008fdac1273410b526c79c278512b985de66fea6eb883ca3b3d"`
[INFO] running `"docker" "rm" "-f" "e95d1e271f239008fdac1273410b526c79c278512b985de66fea6eb883ca3b3d"`
[INFO] [stdout] e95d1e271f239008fdac1273410b526c79c278512b985de66fea6eb883ca3b3d