[INFO] updating cached repository learn-you-a-rust/return_values
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/learn-you-a-rust/return_values
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/learn-you-a-rust/return_values" "work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/learn-you-a-rust/return_values" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/learn-you-a-rust/return_values"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/learn-you-a-rust/return_values'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 909d38d1f4f6cefcc5ba7ce7d8b1454ea4bcabe1
[INFO] sha for GitHub repo learn-you-a-rust/return_values: 909d38d1f4f6cefcc5ba7ce7d8b1454ea4bcabe1
[INFO] validating manifest of learn-you-a-rust/return_values 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 learn-you-a-rust/return_values 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 learn-you-a-rust/return_values
[INFO] finished frobbing learn-you-a-rust/return_values
[INFO] frobbed toml for learn-you-a-rust/return_values written to work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values/Cargo.toml
[INFO] started frobbing learn-you-a-rust/return_values
[INFO] finished frobbing learn-you-a-rust/return_values
[INFO] frobbed toml for learn-you-a-rust/return_values written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/learn-you-a-rust/return_values/Cargo.toml
[INFO] crate learn-you-a-rust/return_values 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 learn-you-a-rust/return_values 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-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values:/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] fe3818d7e3325d2c31ec07499e3ff31225e65d4cc2292fdab135b666c6ac1ee6
[INFO] running `"docker" "start" "-a" "fe3818d7e3325d2c31ec07499e3ff31225e65d4cc2292fdab135b666c6ac1ee6"`
[INFO] [stderr]    Compiling return_values v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.30s
[INFO] running `"docker" "inspect" "fe3818d7e3325d2c31ec07499e3ff31225e65d4cc2292fdab135b666c6ac1ee6"`
[INFO] running `"docker" "rm" "-f" "fe3818d7e3325d2c31ec07499e3ff31225e65d4cc2292fdab135b666c6ac1ee6"`
[INFO] [stdout] fe3818d7e3325d2c31ec07499e3ff31225e65d4cc2292fdab135b666c6ac1ee6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values:/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] f0d026d5bdf464ac0be7ff703d22638c908aff82282df4b6c200c0f44753c00a
[INFO] running `"docker" "start" "-a" "f0d026d5bdf464ac0be7ff703d22638c908aff82282df4b6c200c0f44753c00a"`
[INFO] [stderr]    Compiling return_values v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.30s
[INFO] running `"docker" "inspect" "f0d026d5bdf464ac0be7ff703d22638c908aff82282df4b6c200c0f44753c00a"`
[INFO] running `"docker" "rm" "-f" "f0d026d5bdf464ac0be7ff703d22638c908aff82282df4b6c200c0f44753c00a"`
[INFO] [stdout] f0d026d5bdf464ac0be7ff703d22638c908aff82282df4b6c200c0f44753c00a
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/learn-you-a-rust/return_values:/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] d8656c1248602086a0c93bc6fcf3df7683fda88e9b6c2b4f81b13b8e5cfc6b59
[INFO] running `"docker" "start" "-a" "d8656c1248602086a0c93bc6fcf3df7683fda88e9b6c2b4f81b13b8e5cfc6b59"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.00s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/return_values-52b6babe4707fec5
[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" "d8656c1248602086a0c93bc6fcf3df7683fda88e9b6c2b4f81b13b8e5cfc6b59"`
[INFO] running `"docker" "rm" "-f" "d8656c1248602086a0c93bc6fcf3df7683fda88e9b6c2b4f81b13b8e5cfc6b59"`
[INFO] [stdout] d8656c1248602086a0c93bc6fcf3df7683fda88e9b6c2b4f81b13b8e5cfc6b59