[INFO] updating cached repository kuroega/rust_from_the_book
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/kuroega/rust_from_the_book
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/kuroega/rust_from_the_book" "work/ex/beta-1.38-1/sources/1.37.0/gh/kuroega/rust_from_the_book"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/kuroega/rust_from_the_book'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/kuroega/rust_from_the_book" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kuroega/rust_from_the_book"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kuroega/rust_from_the_book'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] a7f81d228dbf4042d3a2e02a087c307a20373d0d
[INFO] sha for GitHub repo kuroega/rust_from_the_book: a7f81d228dbf4042d3a2e02a087c307a20373d0d
[INFO] validating manifest of kuroega/rust_from_the_book 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 kuroega/rust_from_the_book 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 kuroega/rust_from_the_book
[INFO] finished frobbing kuroega/rust_from_the_book
[INFO] frobbed toml for kuroega/rust_from_the_book written to work/ex/beta-1.38-1/sources/1.37.0/gh/kuroega/rust_from_the_book/Cargo.toml
[INFO] started frobbing kuroega/rust_from_the_book
[INFO] finished frobbing kuroega/rust_from_the_book
[INFO] frobbed toml for kuroega/rust_from_the_book written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kuroega/rust_from_the_book/Cargo.toml
[INFO] crate kuroega/rust_from_the_book 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing kuroega/rust_from_the_book 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/kuroega/rust_from_the_book:/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] 1d54ba960fb704209c499d1d5b09d155532f1e471c91b3401150de91b4ad89d5
[INFO] running `"docker" "start" "-a" "1d54ba960fb704209c499d1d5b09d155532f1e471c91b3401150de91b4ad89d5"`
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling learn-rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.43s
[INFO] running `"docker" "inspect" "1d54ba960fb704209c499d1d5b09d155532f1e471c91b3401150de91b4ad89d5"`
[INFO] running `"docker" "rm" "-f" "1d54ba960fb704209c499d1d5b09d155532f1e471c91b3401150de91b4ad89d5"`
[INFO] [stdout] 1d54ba960fb704209c499d1d5b09d155532f1e471c91b3401150de91b4ad89d5
[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/kuroega/rust_from_the_book:/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] 147bb4f47643f23ce0cf06d5a64a8085a3d5360d5746270844db0084bc289de5
[INFO] running `"docker" "start" "-a" "147bb4f47643f23ce0cf06d5a64a8085a3d5360d5746270844db0084bc289de5"`
[INFO] [stderr]    Compiling learn-rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `s1`
[INFO] [stderr]   --> examples/ownership_demo.rs:16:9
[INFO] [stderr]    |
[INFO] [stderr] 16 |     let s1 = gives_ownership();
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_variables)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s3`
[INFO] [stderr]   --> examples/ownership_demo.rs:18:9
[INFO] [stderr]    |
[INFO] [stderr] 18 |     let s3  = takes_and_gives_back(s2);
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_s3`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never used: `username`
[INFO] [stderr]  --> examples/struct_demo3.rs:2:5
[INFO] [stderr]   |
[INFO] [stderr] 2 |     username: String,
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never used: `active`
[INFO] [stderr]  --> examples/struct_demo3.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     active: bool,
[INFO] [stderr]   |     ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.48s
[INFO] running `"docker" "inspect" "147bb4f47643f23ce0cf06d5a64a8085a3d5360d5746270844db0084bc289de5"`
[INFO] running `"docker" "rm" "-f" "147bb4f47643f23ce0cf06d5a64a8085a3d5360d5746270844db0084bc289de5"`
[INFO] [stdout] 147bb4f47643f23ce0cf06d5a64a8085a3d5360d5746270844db0084bc289de5
[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/kuroega/rust_from_the_book:/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] 4363ec46da146673fe269d7fdb328536d35948a68b3630a16dc869996c195b67
[INFO] running `"docker" "start" "-a" "4363ec46da146673fe269d7fdb328536d35948a68b3630a16dc869996c195b67"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/learn_rust-008414132ae9f736
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::it_works ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests learn_rust
[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" "4363ec46da146673fe269d7fdb328536d35948a68b3630a16dc869996c195b67"`
[INFO] running `"docker" "rm" "-f" "4363ec46da146673fe269d7fdb328536d35948a68b3630a16dc869996c195b67"`
[INFO] [stdout] 4363ec46da146673fe269d7fdb328536d35948a68b3630a16dc869996c195b67