[INFO] updating cached repository Parfyonator/merkle_tree
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Parfyonator/merkle_tree
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Parfyonator/merkle_tree" "work/ex/beta-1.38-1/sources/1.37.0/gh/Parfyonator/merkle_tree"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Parfyonator/merkle_tree'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Parfyonator/merkle_tree" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Parfyonator/merkle_tree"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Parfyonator/merkle_tree'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f6b7198d3fd038d998f0dc6a081148368f09ed39
[INFO] sha for GitHub repo Parfyonator/merkle_tree: f6b7198d3fd038d998f0dc6a081148368f09ed39
[INFO] validating manifest of Parfyonator/merkle_tree 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 Parfyonator/merkle_tree 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 Parfyonator/merkle_tree
[INFO] finished frobbing Parfyonator/merkle_tree
[INFO] frobbed toml for Parfyonator/merkle_tree written to work/ex/beta-1.38-1/sources/1.37.0/gh/Parfyonator/merkle_tree/Cargo.toml
[INFO] started frobbing Parfyonator/merkle_tree
[INFO] finished frobbing Parfyonator/merkle_tree
[INFO] frobbed toml for Parfyonator/merkle_tree written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Parfyonator/merkle_tree/Cargo.toml
[INFO] crate Parfyonator/merkle_tree 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 Parfyonator/merkle_tree 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-6/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/Parfyonator/merkle_tree:/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] 918470d671e986fbf46b158a16a22bee0dc20ebb2049d0cce8ac91f7da642cc9
[INFO] running `"docker" "start" "-a" "918470d671e986fbf46b158a16a22bee0dc20ebb2049d0cce8ac91f7da642cc9"`
[INFO] [stderr]    Compiling rustc-serialize v0.3.23
[INFO] [stderr]    Compiling rust-crypto v0.2.36
[INFO] [stderr]    Compiling hyper v0.10.5
[INFO] [stderr]    Compiling url v1.4.0
[INFO] [stderr] warning[E0713]: borrow may still be in use when destructor runs
[INFO] [stderr]    --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/url-1.4.0/src/form_urlencoded.rs:246:40
[INFO] [stderr]     |
[INFO] [stderr] 244 | impl<'a> Target for ::UrlQuery<'a> {
[INFO] [stderr]     |      -- lifetime `'a` defined here
[INFO] [stderr] 245 |     fn as_mut_string(&mut self) -> &mut String { &mut self.url.serialization }
[INFO] [stderr] 246 |     fn finish(self) -> &'a mut ::Url { self.url }
[INFO] [stderr]     |                                        ^^^^^^^^ - here, drop of `self` needs exclusive access to `*self.url`, because the type `UrlQuery<'_>` implements the `Drop` trait
[INFO] [stderr]     |                                        |
[INFO] [stderr]     |                                        returning this value requires that `*self.url` is borrowed for `'a`
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
[INFO] [stderr]     = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
[INFO] [stderr]     = note: for more information, try `rustc --explain E0729`
[INFO] [stderr] 
[INFO] [stderr]    Compiling merkle_tree v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: method is never used: `add_child`
[INFO] [stderr]   --> src/merkle_tree.rs:60:5
[INFO] [stderr]    |
[INFO] [stderr] 60 |     fn add_child(&mut self, new_val: String) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `has_children`
[INFO] [stderr]   --> src/merkle_tree.rs:74:5
[INFO] [stderr]    |
[INFO] [stderr] 74 |     fn has_children(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 19.21s
[INFO] running `"docker" "inspect" "918470d671e986fbf46b158a16a22bee0dc20ebb2049d0cce8ac91f7da642cc9"`
[INFO] running `"docker" "rm" "-f" "918470d671e986fbf46b158a16a22bee0dc20ebb2049d0cce8ac91f7da642cc9"`
[INFO] [stdout] 918470d671e986fbf46b158a16a22bee0dc20ebb2049d0cce8ac91f7da642cc9
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/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/Parfyonator/merkle_tree:/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] 3647aa72011ca65c3f846a3b56d5c78e820b20b974672fbf7e94e1713119969c
[INFO] running `"docker" "start" "-a" "3647aa72011ca65c3f846a3b56d5c78e820b20b974672fbf7e94e1713119969c"`
[INFO] [stderr]    Compiling merkle_tree v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: method is never used: `add_child`
[INFO] [stderr]   --> src/merkle_tree.rs:60:5
[INFO] [stderr]    |
[INFO] [stderr] 60 |     fn add_child(&mut self, new_val: String) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `has_children`
[INFO] [stderr]   --> src/merkle_tree.rs:74:5
[INFO] [stderr]    |
[INFO] [stderr] 74 |     fn has_children(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.91s
[INFO] running `"docker" "inspect" "3647aa72011ca65c3f846a3b56d5c78e820b20b974672fbf7e94e1713119969c"`
[INFO] running `"docker" "rm" "-f" "3647aa72011ca65c3f846a3b56d5c78e820b20b974672fbf7e94e1713119969c"`
[INFO] [stdout] 3647aa72011ca65c3f846a3b56d5c78e820b20b974672fbf7e94e1713119969c
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/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/Parfyonator/merkle_tree:/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] 3610b4b57d000390bdf5c805151b569560c56a50a94ac3975c39f81545f30faa
[INFO] running `"docker" "start" "-a" "3610b4b57d000390bdf5c805151b569560c56a50a94ac3975c39f81545f30faa"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.06s
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/crater/target/debug/deps/merkle_tree-b91274e39749419d
[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" "3610b4b57d000390bdf5c805151b569560c56a50a94ac3975c39f81545f30faa"`
[INFO] running `"docker" "rm" "-f" "3610b4b57d000390bdf5c805151b569560c56a50a94ac3975c39f81545f30faa"`
[INFO] [stdout] 3610b4b57d000390bdf5c805151b569560c56a50a94ac3975c39f81545f30faa