[INFO] updating cached repository syntheticsh/binary-play
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/syntheticsh/binary-play
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/syntheticsh/binary-play" "work/ex/beta-1.38-1/sources/1.37.0/gh/syntheticsh/binary-play"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/syntheticsh/binary-play'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/syntheticsh/binary-play" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/syntheticsh/binary-play"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/syntheticsh/binary-play'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 2ef5ff608528a7ce2e4a22f44bd1871aab525fd7
[INFO] sha for GitHub repo syntheticsh/binary-play: 2ef5ff608528a7ce2e4a22f44bd1871aab525fd7
[INFO] validating manifest of syntheticsh/binary-play 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 syntheticsh/binary-play 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 syntheticsh/binary-play
[INFO] finished frobbing syntheticsh/binary-play
[INFO] frobbed toml for syntheticsh/binary-play written to work/ex/beta-1.38-1/sources/1.37.0/gh/syntheticsh/binary-play/Cargo.toml
[INFO] started frobbing syntheticsh/binary-play
[INFO] finished frobbing syntheticsh/binary-play
[INFO] frobbed toml for syntheticsh/binary-play written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/syntheticsh/binary-play/Cargo.toml
[INFO] crate syntheticsh/binary-play 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 syntheticsh/binary-play 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-2/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/syntheticsh/binary-play:/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] 06e051f035d844a76eb10a3044b162ba69d2bce2b1b9efcd908f9610188d7865
[INFO] running `"docker" "start" "-a" "06e051f035d844a76eb10a3044b162ba69d2bce2b1b9efcd908f9610188d7865"`
[INFO] [stderr]    Compiling binary v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/lib.rs:222:26
[INFO] [stderr]     |
[INFO] [stderr] 222 |                     let (mut detached_head, mut right) = head_tree.take_right();
[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/lib.rs:222:45
[INFO] [stderr]     |
[INFO] [stderr] 222 |                     let (mut detached_head, mut right) = head_tree.take_right();
[INFO] [stderr]     |                                             ----^^^^^
[INFO] [stderr]     |                                             |
[INFO] [stderr]     |                                             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:41:13
[INFO] [stderr]    |
[INFO] [stderr] 41 |         let mut left = branch.as_mut();
[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:46:13
[INFO] [stderr]    |
[INFO] [stderr] 46 |         let mut right = branch.as_mut();
[INFO] [stderr]    |             ----^^^^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.57s
[INFO] running `"docker" "inspect" "06e051f035d844a76eb10a3044b162ba69d2bce2b1b9efcd908f9610188d7865"`
[INFO] running `"docker" "rm" "-f" "06e051f035d844a76eb10a3044b162ba69d2bce2b1b9efcd908f9610188d7865"`
[INFO] [stdout] 06e051f035d844a76eb10a3044b162ba69d2bce2b1b9efcd908f9610188d7865
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/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/syntheticsh/binary-play:/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" "test" "--frozen" "--no-run"`
[INFO] [stdout] 6c59ffa6b3d46c5748537f71c73a61bac7735937d1c6fb97790d242cc0f5ad25
[INFO] running `"docker" "start" "-a" "6c59ffa6b3d46c5748537f71c73a61bac7735937d1c6fb97790d242cc0f5ad25"`
[INFO] [stderr]    Compiling binary v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:41:13
[INFO] [stderr]    |
[INFO] [stderr] 41 |         let mut left = branch.as_mut();
[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:46:13
[INFO] [stderr]    |
[INFO] [stderr] 46 |         let mut right = branch.as_mut();
[INFO] [stderr]    |             ----^^^^^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/lib.rs:222:26
[INFO] [stderr]     |
[INFO] [stderr] 222 |                     let (mut detached_head, mut right) = head_tree.take_right();
[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/lib.rs:222:45
[INFO] [stderr]     |
[INFO] [stderr] 222 |                     let (mut detached_head, mut right) = head_tree.take_right();
[INFO] [stderr]     |                                             ----^^^^^
[INFO] [stderr]     |                                             |
[INFO] [stderr]     |                                             help: remove this `mut`
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.89s
[INFO] running `"docker" "inspect" "6c59ffa6b3d46c5748537f71c73a61bac7735937d1c6fb97790d242cc0f5ad25"`
[INFO] running `"docker" "rm" "-f" "6c59ffa6b3d46c5748537f71c73a61bac7735937d1c6fb97790d242cc0f5ad25"`
[INFO] [stdout] 6c59ffa6b3d46c5748537f71c73a61bac7735937d1c6fb97790d242cc0f5ad25
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/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/syntheticsh/binary-play:/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" "test" "--frozen"`
[INFO] [stdout] 7169e13c5b2661287dfc326ae13e9bebc92e3ad89c7d889b047c8038cc18ae8a
[INFO] running `"docker" "start" "-a" "7169e13c5b2661287dfc326ae13e9bebc92e3ad89c7d889b047c8038cc18ae8a"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.03s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/binary-20842ecd66f6cb89
[INFO] [stderr]      Running /opt/crater/target/debug/deps/binary-962d5cacb4cd699b
[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] [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 binary
[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" "7169e13c5b2661287dfc326ae13e9bebc92e3ad89c7d889b047c8038cc18ae8a"`
[INFO] running `"docker" "rm" "-f" "7169e13c5b2661287dfc326ae13e9bebc92e3ad89c7d889b047c8038cc18ae8a"`
[INFO] [stdout] 7169e13c5b2661287dfc326ae13e9bebc92e3ad89c7d889b047c8038cc18ae8a