[INFO] crate tail 0.3.0 is already in cache
[INFO] extracting crate tail 0.3.0 into work/ex/beta-1.37-6/sources/1.36.0/reg/tail/0.3.0
[INFO] extracting crate tail 0.3.0 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tail/0.3.0
[INFO] validating manifest of tail-0.3.0 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of tail-0.3.0 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing tail-0.3.0
[INFO] finished frobbing tail-0.3.0
[INFO] frobbed toml for tail-0.3.0 written to work/ex/beta-1.37-6/sources/1.36.0/reg/tail/0.3.0/Cargo.toml
[INFO] started frobbing tail-0.3.0
[INFO] finished frobbing tail-0.3.0
[INFO] frobbed toml for tail-0.3.0 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tail/0.3.0/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing tail-0.3.0 against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tail/0.3.0:/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-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 0cf74df6110922d92dc41fac5e56eafcd6c8c11f2473bee9de3df27cf9559501
[INFO] running `"docker" "start" "-a" "0cf74df6110922d92dc41fac5e56eafcd6c8c11f2473bee9de3df27cf9559501"`
[INFO] [stderr]    Compiling tail v0.3.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:88:13
[INFO] [stderr]    |
[INFO] [stderr] 88 |         let mut wd = watcher.add_watch(Path::new(&file_name), WatchMask::MODIFY)
[INFO] [stderr]    |             ----^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:90:13
[INFO] [stderr]    |
[INFO] [stderr] 90 |         let mut fd = File::open(&file_name)
[INFO] [stderr]    |             ----^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.69s
[INFO] running `"docker" "inspect" "0cf74df6110922d92dc41fac5e56eafcd6c8c11f2473bee9de3df27cf9559501"`
[INFO] running `"docker" "rm" "-f" "0cf74df6110922d92dc41fac5e56eafcd6c8c11f2473bee9de3df27cf9559501"`
[INFO] [stdout] 0cf74df6110922d92dc41fac5e56eafcd6c8c11f2473bee9de3df27cf9559501
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tail/0.3.0:/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-2019-07-23" "test" "--frozen" "--no-run"`
[INFO] [stdout] e0d220130ac17ad6e30aa2e103ca2a2a0c7da65d499453996932f4867ccb8e08
[INFO] running `"docker" "start" "-a" "e0d220130ac17ad6e30aa2e103ca2a2a0c7da65d499453996932f4867ccb8e08"`
[INFO] [stderr]    Compiling tail v0.3.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:88:13
[INFO] [stderr]    |
[INFO] [stderr] 88 |         let mut wd = watcher.add_watch(Path::new(&file_name), WatchMask::MODIFY)
[INFO] [stderr]    |             ----^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:90:13
[INFO] [stderr]    |
[INFO] [stderr] 90 |         let mut fd = File::open(&file_name)
[INFO] [stderr]    |             ----^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.13s
[INFO] running `"docker" "inspect" "e0d220130ac17ad6e30aa2e103ca2a2a0c7da65d499453996932f4867ccb8e08"`
[INFO] running `"docker" "rm" "-f" "e0d220130ac17ad6e30aa2e103ca2a2a0c7da65d499453996932f4867ccb8e08"`
[INFO] [stdout] e0d220130ac17ad6e30aa2e103ca2a2a0c7da65d499453996932f4867ccb8e08
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tail/0.3.0:/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-2019-07-23" "test" "--frozen"`
[INFO] [stdout] d741100a6ee45bdc688d77141b1fd62cad6686f8aa13a76a01c1a06c2c649b67
[INFO] running `"docker" "start" "-a" "d741100a6ee45bdc688d77141b1fd62cad6686f8aa13a76a01c1a06c2c649b67"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/tail-9c6610b1a8ea51fb
[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] [stderr]      Running /opt/crater/target/debug/deps/tail-1c0cade297c31f03
[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] [stderr]    Doc-tests tail
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test src/lib.rs - BackwardsReader (line 23) ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/lib.rs - BackwardsReader (line 23) stdout ----
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `BufWriter`
[INFO] [stdout]  --> src/lib.rs:24:18
[INFO] [stdout]   |
[INFO] [stdout] 3 | let mut writer = BufWriter::new(std::io::stdout());
[INFO] [stdout]   |                  ^^^^^^^^^ use of undeclared type or module `BufWriter`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `BackwardsReader`
[INFO] [stdout]  --> src/lib.rs:25:18
[INFO] [stdout]   |
[INFO] [stdout] 4 | let mut reader = BackwardsReader::new(10, &mut writer);
[INFO] [stdout]   |                  ^^^^^^^^^^^^^^^ use of undeclared type or module `BackwardsReader`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0433`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/lib.rs - BackwardsReader (line 23)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr] error: test failed, to rerun pass '--doc'
[INFO] running `"docker" "inspect" "d741100a6ee45bdc688d77141b1fd62cad6686f8aa13a76a01c1a06c2c649b67"`
[INFO] running `"docker" "rm" "-f" "d741100a6ee45bdc688d77141b1fd62cad6686f8aa13a76a01c1a06c2c649b67"`
[INFO] [stdout] d741100a6ee45bdc688d77141b1fd62cad6686f8aa13a76a01c1a06c2c649b67