[INFO] updating cached repository Dhole/rust_learning
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Dhole/rust_learning
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Dhole/rust_learning" "work/ex/beta-1.38-1/sources/1.37.0/gh/Dhole/rust_learning"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Dhole/rust_learning'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Dhole/rust_learning" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Dhole/rust_learning"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Dhole/rust_learning'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] d05e463827e5ebb860a379c3714631acf7e3d728
[INFO] sha for GitHub repo Dhole/rust_learning: d05e463827e5ebb860a379c3714631acf7e3d728
[INFO] validating manifest of Dhole/rust_learning 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 Dhole/rust_learning 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 Dhole/rust_learning
[INFO] finished frobbing Dhole/rust_learning
[INFO] frobbed toml for Dhole/rust_learning written to work/ex/beta-1.38-1/sources/1.37.0/gh/Dhole/rust_learning/Cargo.toml
[INFO] started frobbing Dhole/rust_learning
[INFO] finished frobbing Dhole/rust_learning
[INFO] frobbed toml for Dhole/rust_learning written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Dhole/rust_learning/Cargo.toml
[INFO] crate Dhole/rust_learning 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 Dhole/rust_learning 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-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/Dhole/rust_learning:/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] b70774fcda53b8ae07cb348a191a680eab604163d1633f2cffddcb77094fa5da
[INFO] running `"docker" "start" "-a" "b70774fcda53b8ae07cb348a191a680eab604163d1633f2cffddcb77094fa5da"`
[INFO] [stderr]    Compiling learn v0.0.1 (/opt/crater/workdir)
[INFO] [stderr] error[E0432]: unresolved import `std::rand`
[INFO] [stderr]   --> src/main.rs:53:5
[INFO] [stderr]    |
[INFO] [stderr] 53 | use std::rand;
[INFO] [stderr]    |     ^^^^^^^^^ no `rand` in the root
[INFO] [stderr] 
[INFO] [stderr] error[E0432]: unresolved import `std::rand`
[INFO] [stderr]   --> src/main.rs:54:10
[INFO] [stderr]    |
[INFO] [stderr] 54 | use std::rand::Rng;
[INFO] [stderr]    |          ^^^^ could not find `rand` in `std`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0432`.
[INFO] [stderr] error: Could not compile `learn`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "b70774fcda53b8ae07cb348a191a680eab604163d1633f2cffddcb77094fa5da"`
[INFO] running `"docker" "rm" "-f" "b70774fcda53b8ae07cb348a191a680eab604163d1633f2cffddcb77094fa5da"`
[INFO] [stdout] b70774fcda53b8ae07cb348a191a680eab604163d1633f2cffddcb77094fa5da