[INFO] updating cached repository ravendyg/rust-playground
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/ravendyg/rust-playground
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/ravendyg/rust-playground" "work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/ravendyg/rust-playground" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ravendyg/rust-playground"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ravendyg/rust-playground'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f0fbaf1c751f3fbfd6b05d9779721bfa5fc7f25f
[INFO] sha for GitHub repo ravendyg/rust-playground: f0fbaf1c751f3fbfd6b05d9779721bfa5fc7f25f
[INFO] validating manifest of ravendyg/rust-playground 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 ravendyg/rust-playground 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 ravendyg/rust-playground
[INFO] finished frobbing ravendyg/rust-playground
[INFO] frobbed toml for ravendyg/rust-playground written to work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground/Cargo.toml
[INFO] started frobbing ravendyg/rust-playground
[INFO] finished frobbing ravendyg/rust-playground
[INFO] frobbed toml for ravendyg/rust-playground written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/ravendyg/rust-playground/Cargo.toml
[INFO] crate ravendyg/rust-playground 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 ravendyg/rust-playground 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-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground:/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] bfcf3e89ce89a4556d012a2c3629fe537f0844f713104ee89685e111db0bc476
[INFO] running `"docker" "start" "-a" "bfcf3e89ce89a4556d012a2c3629fe537f0844f713104ee89685e111db0bc476"`
[INFO] [stderr]    Compiling guessing v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/main.rs:60:7
[INFO] [stderr]    |
[INFO] [stderr] 60 |   let x: Option<i32> = Option::Some(5);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `q`
[INFO] [stderr]   --> src/main.rs:62:7
[INFO] [stderr]    |
[INFO] [stderr] 62 |   let q: Option<f64> = Option::Some(5f64);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_q`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `b`
[INFO] [stderr]   --> src/main.rs:71:7
[INFO] [stderr]    |
[INFO] [stderr] 71 |   let b = 10;
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_b`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/main.rs:49:3
[INFO] [stderr]    |
[INFO] [stderr] 49 |   None
[INFO] [stderr]    |   ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Result`
[INFO] [stderr]   --> src/main.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | enum Result<T, E> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.58s
[INFO] running `"docker" "inspect" "bfcf3e89ce89a4556d012a2c3629fe537f0844f713104ee89685e111db0bc476"`
[INFO] running `"docker" "rm" "-f" "bfcf3e89ce89a4556d012a2c3629fe537f0844f713104ee89685e111db0bc476"`
[INFO] [stdout] bfcf3e89ce89a4556d012a2c3629fe537f0844f713104ee89685e111db0bc476
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground:/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] 754d93d2847a93ddf92af816188b71dd3e1a6f6abbb2c876736298dda7b67709
[INFO] running `"docker" "start" "-a" "754d93d2847a93ddf92af816188b71dd3e1a6f6abbb2c876736298dda7b67709"`
[INFO] [stderr]    Compiling guessing v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]   --> src/main.rs:60:7
[INFO] [stderr]    |
[INFO] [stderr] 60 |   let x: Option<i32> = Option::Some(5);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `q`
[INFO] [stderr]   --> src/main.rs:62:7
[INFO] [stderr]    |
[INFO] [stderr] 62 |   let q: Option<f64> = Option::Some(5f64);
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_q`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `b`
[INFO] [stderr]   --> src/main.rs:71:7
[INFO] [stderr]    |
[INFO] [stderr] 71 |   let b = 10;
[INFO] [stderr]    |       ^ help: consider prefixing with an underscore: `_b`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `None`
[INFO] [stderr]   --> src/main.rs:49:3
[INFO] [stderr]    |
[INFO] [stderr] 49 |   None
[INFO] [stderr]    |   ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Result`
[INFO] [stderr]   --> src/main.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | enum Result<T, E> {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.72s
[INFO] running `"docker" "inspect" "754d93d2847a93ddf92af816188b71dd3e1a6f6abbb2c876736298dda7b67709"`
[INFO] running `"docker" "rm" "-f" "754d93d2847a93ddf92af816188b71dd3e1a6f6abbb2c876736298dda7b67709"`
[INFO] [stdout] 754d93d2847a93ddf92af816188b71dd3e1a6f6abbb2c876736298dda7b67709
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/ravendyg/rust-playground:/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] b4da5b4f51a0e8d7f80a2b003c1bdbbf147429c3ab85a1caf7e77c341fb19840
[INFO] running `"docker" "start" "-a" "b4da5b4f51a0e8d7f80a2b003c1bdbbf147429c3ab85a1caf7e77c341fb19840"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/guessing-beaee95cf8e91240
[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" "b4da5b4f51a0e8d7f80a2b003c1bdbbf147429c3ab85a1caf7e77c341fb19840"`
[INFO] running `"docker" "rm" "-f" "b4da5b4f51a0e8d7f80a2b003c1bdbbf147429c3ab85a1caf7e77c341fb19840"`
[INFO] [stdout] b4da5b4f51a0e8d7f80a2b003c1bdbbf147429c3ab85a1caf7e77c341fb19840