[INFO] updating cached repository torkeldanielsson/fraction_problems_generator
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/torkeldanielsson/fraction_problems_generator
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/torkeldanielsson/fraction_problems_generator" "work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/torkeldanielsson/fraction_problems_generator" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 4de0983a740f35130066c9eafd39386d82348861
[INFO] sha for GitHub repo torkeldanielsson/fraction_problems_generator: 4de0983a740f35130066c9eafd39386d82348861
[INFO] validating manifest of torkeldanielsson/fraction_problems_generator 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 torkeldanielsson/fraction_problems_generator 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 torkeldanielsson/fraction_problems_generator
[INFO] finished frobbing torkeldanielsson/fraction_problems_generator
[INFO] frobbed toml for torkeldanielsson/fraction_problems_generator written to work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator/Cargo.toml
[INFO] started frobbing torkeldanielsson/fraction_problems_generator
[INFO] finished frobbing torkeldanielsson/fraction_problems_generator
[INFO] frobbed toml for torkeldanielsson/fraction_problems_generator written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator/Cargo.toml
[INFO] crate torkeldanielsson/fraction_problems_generator 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 torkeldanielsson/fraction_problems_generator against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator:/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" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] a7d782669e57d7ec1a735ee4726162318cabf53ed9723dc3b7551b7b85598237
[INFO] running `"docker" "start" "-a" "a7d782669e57d7ec1a735ee4726162318cabf53ed9723dc3b7551b7b85598237"`
[INFO] [stderr]    Compiling rand v0.3.18
[INFO] [stderr]    Compiling math_gen v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:225:13
[INFO] [stderr]     |
[INFO] [stderr] 225 |         let mut a: i32 = rand::distributions::Range::new(3, 10).ind_sample(&mut rng);
[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 4.44s
[INFO] running `"docker" "inspect" "a7d782669e57d7ec1a735ee4726162318cabf53ed9723dc3b7551b7b85598237"`
[INFO] running `"docker" "rm" "-f" "a7d782669e57d7ec1a735ee4726162318cabf53ed9723dc3b7551b7b85598237"`
[INFO] [stdout] a7d782669e57d7ec1a735ee4726162318cabf53ed9723dc3b7551b7b85598237
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator:/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" "+beta-2019-08-13" "test" "--frozen" "--no-run"`
[INFO] [stdout] 66d9bb8f6ba3fe344075ee8a20128c1ac4070ab41b9ecb65edafaa32a949f925
[INFO] running `"docker" "start" "-a" "66d9bb8f6ba3fe344075ee8a20128c1ac4070ab41b9ecb65edafaa32a949f925"`
[INFO] [stderr]    Compiling math_gen v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:225:13
[INFO] [stderr]     |
[INFO] [stderr] 225 |         let mut a: i32 = rand::distributions::Range::new(3, 10).ind_sample(&mut rng);
[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 1.77s
[INFO] running `"docker" "inspect" "66d9bb8f6ba3fe344075ee8a20128c1ac4070ab41b9ecb65edafaa32a949f925"`
[INFO] running `"docker" "rm" "-f" "66d9bb8f6ba3fe344075ee8a20128c1ac4070ab41b9ecb65edafaa32a949f925"`
[INFO] [stdout] 66d9bb8f6ba3fe344075ee8a20128c1ac4070ab41b9ecb65edafaa32a949f925
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator:/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" "+beta-2019-08-13" "test" "--frozen"`
[INFO] [stdout] f0b01b10201cda4c3de0cb2024048746b3bb6cb587893d8604b5091831efd838
[INFO] running `"docker" "start" "-a" "f0b01b10201cda4c3de0cb2024048746b3bb6cb587893d8604b5091831efd838"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/math_gen-ec05029ec54b7cae
[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" "f0b01b10201cda4c3de0cb2024048746b3bb6cb587893d8604b5091831efd838"`
[INFO] running `"docker" "rm" "-f" "f0b01b10201cda4c3de0cb2024048746b3bb6cb587893d8604b5091831efd838"`
[INFO] [stdout] f0b01b10201cda4c3de0cb2024048746b3bb6cb587893d8604b5091831efd838