[INFO] updating cached repository rhodium45/blockchain
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/rhodium45/blockchain
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/rhodium45/blockchain" "work/ex/beta-1.38-1/sources/1.37.0/gh/rhodium45/blockchain"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/rhodium45/blockchain'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/rhodium45/blockchain" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rhodium45/blockchain"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rhodium45/blockchain'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 32cd3a16944cd37393a311314ad157a3a7f621ab
[INFO] sha for GitHub repo rhodium45/blockchain: 32cd3a16944cd37393a311314ad157a3a7f621ab
[INFO] validating manifest of rhodium45/blockchain 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 rhodium45/blockchain 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 rhodium45/blockchain
[INFO] finished frobbing rhodium45/blockchain
[INFO] frobbed toml for rhodium45/blockchain written to work/ex/beta-1.38-1/sources/1.37.0/gh/rhodium45/blockchain/Cargo.toml
[INFO] started frobbing rhodium45/blockchain
[INFO] finished frobbing rhodium45/blockchain
[INFO] frobbed toml for rhodium45/blockchain written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rhodium45/blockchain/Cargo.toml
[INFO] crate rhodium45/blockchain 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 rhodium45/blockchain 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/rhodium45/blockchain:/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] 8b3ea17fd3552bbae58a2ab8f59532a50622705a9a131abc7f7936eb9708dc57
[INFO] running `"docker" "start" "-a" "8b3ea17fd3552bbae58a2ab8f59532a50622705a9a131abc7f7936eb9708dc57"`
[INFO] [stderr]    Compiling serde v1.0.42
[INFO] [stderr]    Compiling proc-macro2 v0.3.6
[INFO] [stderr]    Compiling digest v0.7.2
[INFO] [stderr]    Compiling sha2 v0.7.0
[INFO] [stderr]    Compiling quote v0.5.2
[INFO] [stderr]    Compiling syn v0.13.1
[INFO] [stderr]    Compiling serde_derive_internals v0.23.1
[INFO] [stderr]    Compiling serde_derive v1.0.42
[INFO] [stderr]    Compiling serde_json v1.0.16
[INFO] [stderr]    Compiling blockchain v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0308]: mismatched types
[INFO] [stderr]    --> src/blockchain.rs:171:9
[INFO] [stderr]     |
[INFO] [stderr] 169 |       pub fn hex_to_string(vec_res: &[u8]) -> String {
[INFO] [stderr]     |                                               ------ expected `std::string::String` because of return type
[INFO] [stderr] 170 |           let mut s = String::new();
[INFO] [stderr] 171 | /         for b in vec_res {
[INFO] [stderr] 172 | |             write!(&mut s, "{:x}", b).expect("unable to write");
[INFO] [stderr] 173 | |         }
[INFO] [stderr]     | |_________^ expected struct `std::string::String`, found ()
[INFO] [stderr]     |
[INFO] [stderr]     = note: expected type `std::string::String`
[INFO] [stderr]                found type `()`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0308`.
[INFO] [stderr] error: Could not compile `blockchain`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "8b3ea17fd3552bbae58a2ab8f59532a50622705a9a131abc7f7936eb9708dc57"`
[INFO] running `"docker" "rm" "-f" "8b3ea17fd3552bbae58a2ab8f59532a50622705a9a131abc7f7936eb9708dc57"`
[INFO] [stdout] 8b3ea17fd3552bbae58a2ab8f59532a50622705a9a131abc7f7936eb9708dc57